testing of belimo pressure independent...

TESTING OF BELIMO PRESSURE INDEPENDENT

CHARACTERIZED CONTROL VALVES

November, 2005

Submitted by: Iowa Energy Center

Address: DMACC, 2006 S. Ankeny Blvd. Ankeny, IA 50021 Phone: 515.965.7055 Fax: 515.965.7056 Web Site: http://www.energy.iastate.edu/

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Conditions Iowa State University, the Iowa Energy Center, and the National Building Controls Information Program (NBCIP) logos may not be used in any advertising or publicity, or otherwise to indicate Iowa State University’s, the Iowa Energy Center’s or NBCIP’s endorsement of or affiliation with any Belimo product or service.

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Executive Summary The objective of the testing described in this report was to evaluate the performance of Belimo pressure independent characterized control valves (PICCV) against conventional globe control valves for terminal reheat and chilled water cooling coil applications in a commercial office building. Testing compared the PICCV to Siemens Powermite MT series globe valves. Testing was performed at the Iowa Energy Center Energy Resource Station (ERS). A brief description of the testing and findings are provided below. Terminal Reheat Open Loop Test: The purpose of this test was to measure the water flow rate through the test valves as a function of the valve position (i.e., % open) and the differential pressure across the valve. Open-loop tests were conducted on a Belimo PICCV-15-003 and a correctly sized Siemens Powermite MT 599-02036 globe valve. Consistent with the manufacturer’s literature, for a differential pressure range of 5 to 30 psi (34.5 to 206.8 kPa), the flow rate through the Belimo PICCV was essentially independent of differential pressure for a fixed valve position. As expected, the flow rate through the Siemens valve increased as the differential pressure increased for a fixed valve position; however, the flow rate though the Siemens valve with the valve fully open was 13 to 15% higher than expected based on the manufacturer’s literature. Testing also revealed that the Belimo valve has an equal percentage characteristic curve, while the Siemens valve has a nearly linear characteristic curve. Terminal Reheat Closed Loop Test – Effect of Valve Sizing on Valve Performance: The purpose of this test was to evaluate the control performance of the PICCV in comparison to a correctly sized and two oversized conventional globe valves. The three Siemens valves included a correctly sized valve (Powermite MT 599-02036 with Cv = 1.6), an oversized valve (Powermite MT 599-02038 with Cv = 2.5), and a very oversized valve (Powermite MT 599-02041 with Cv = 4.0). Control performance was evaluated in terms of the temperature control, actuator travel, actuator starts and stops, actuator reversals, and the cumulative change in the water flow rate. Actuator travel, actuator reversals, and the cumulative change in the water flow rate were consistently and significantly less for the Belimo valve in comparison to the Siemens valves. The Belimo valve also tended to have fewer starts and stops, although there were three cases out of seven where the Belimo valve had a slightly higher number of starts and stops. These results confirm what can be visually observed from plots of the feedback signals of the valves, flow rates through the valves, and temperature responses associated with the valves. Specifically, the Belimo valve control was more stable than the Siemens valve control for the tests conducted and the tuning parameters utilized. The temperature control of the Belimo and Siemens valves was similar, with the exception occurring for operation at low flow rates. The Belimo valve provided stable control under all test conditions (even for the test designated CL 2.4 in which the inlet pressure to the Belimo valve was much more oscillatory than the inlet pressure to the Siemens valve) and was capable of producing stable flow rates below 0.2 GPM (0.013 L/s). By contrast, the Siemens valve had difficulty providing stable flow at low flow rates and instead would tend to open and close periodically with resultant flow rates that fluctuated between 0 and 0.25 GPM (0.016 L/s). As a result, the temperature being controlled tended to fluctuate as well.

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The impact of valve sizing on control performance was made especially apparent by considering the cumulative change in the water flow rate. This parameter, which represents the sum of the change in the water flow rate from the current sampling time to the previous sampling time, increased significantly as the flow coefficient of the Siemens valve increased and the valve authority decreased. Terminal Reheat Closed Loop Test – System Performance Test: The purpose of this test was to compare energy use, control stability, start-up time and other relevant performance characteristics of Belimo PICCVs to correctly sized Siemens Powermite MT globe valves under normal system operating conditions. Based on 19 days of test data, the temperature control of the two valves was comparable, although the Siemens valves were more aggressive and resulted in temperatures that fluctuated around the room setpoint temperature to a greater extent than was seen for the Belimo valves. The difference in the control performance was quantified using the cumulative change in the flow rate. For the perimeter rooms, this parameter was generally two to five times greater for the Siemens valves than for the Belimo valves, indicating superior control on the part of the Belimo valves. There was not a significant difference seen in energy use of the terminal reheat coils controlled by the different brands of valves. The heating water loop pump energy was directly affected by the system differential pressure setpoint. In CL 3.1 and CL 3.2, a higher setpoint was used on the system equipped with Belimo valves and higher energy use resulted. In CL 3.3, the setpoint was the same for the two systems and the energy use was also the same. At low loads, the system equipped with Belimo PICCVs had heating water temperature drops across the reheat coils of the perimeter rooms that were 5 to 9ºF (2.8 to 5ºC) higher than the system with Siemens globe valves with the same system differential setpoint was used for the two heating water loops. The higher temperature drops associated with the Belimo system were accompanied by lower heating water flow rates, although the differences in the flow rates between the Belimo and Siemens systems were small when compared to the design flow rate of the systems. Finally, there was no difference observed in the system startup time between the Belimo and Siemens systems. This finding and the lack of any pumping energy difference may be due in part to the small number of zones served by the ERS test systems and the fact that the ERS systems have a reverse return piping arrangement. AHU Chilled Water Open Loop Test: The purpose of this test was to quantify the water flow rate through the AHU chilled water cooling coil test valves as a function of the valve position (i.e., % open) and the differential pressure across the valve. This test mimicked the Terminal Reheat Open Loop Test. Open-loop tests were conducted on a Belimo PICCV-32-026-PT and a correctly sized Siemens Powermite MT 599-02046 globe valve. Consistent with the manufacturer’s literature, for a differential pressure range of 7 to 15 psi (48.3 to 103.4 kPa), the flow rate through the Belimo PICCV was nearly independent of differential pressure for a fixed valve position. As expected, the flow rate through the Siemens valve increased as the differential pressure increased for a fixed valve position; however, the flow rate though the Siemens valve

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with the valve fully open was 21% lower than expected based on the manufacturer’s literature. Testing also revealed that, like the smaller valves used for the terminal reheat application, the Belimo valve has an equal percentage characteristic curve, while the Siemens valve has a nearly linear characteristic curve. AHU Chilled Water Closed Loop Test – Control Performance: The purpose of this test was to evaluate the control performance of the Belimo PICCV in comparison to a correctly sized conventional globe valve for an AHU chilled water cooling coil application. Testing was conducted on a Belimo PICCV-32-026-PT and a correctly sized Siemens Powermite MT 599-02046 globe valve. Control performance was evaluated in terms of the temperature control, actuator travel, actuator starts and stops, actuator reversals, and the cumulative change in the water flow rate as disturbances were introduced via changes to the supply air temperature setpoint and primary chilled water pump speed. The test was performed twice, first with the Belimo PICCV installed in AHU-A and the Siemens valve in AHU-B for CL 5.1, and then with the Siemens valve installed in AHU-A and the Belimo PICCV in AHU-B for CL 5.2. In both CL 5.1 and CL 5.2, the Belimo PICCV exhibited stable control over the entire test and was capable of providing stable flow as low as 0.99 GPM (0.062 L/s), whereas the Siemens valve exhibited unstable control at flow rates below 4 GPM (0.252 L/s). The inability of the Siemens valve to provide stable flow at low loads resulted in significantly higher values of certain control performance parameters compared to the Belimo valve. For instance, the Siemens valve made three to six times more reversals than the Belimo valve, and the cumulative change in water flow rate associated with the Siemens valve was four or more times that for the Belimo PICCV. The temperature control of the Belimo and Siemens valves was similar, with the exception occurring for operation at low flow rates, where unstable flow rates associated with the Siemens valve led to unstable supply air temperatures. In addition, although the Belimo PICCV demonstrated more stable control than the Siemens valve and produced slightly higher temperature rises across the cooling coil at low load conditions, any pumping energy savings resulting from the improved control performance was not distinguishable in this test. Overall Findings: The tests described above were performed to verify performance characteristics of the Belimo PICCV in comparison to conventional globe valves. A summary of those characteristics and findings from the tests are provided in the table on the following pages.

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Performance Characteristic Findings

Ability to maintain perfect valve authority

The PICCV provided stable control under all operating conditions, even in circumstances where the inlet pressure was very unstable due to unstable control of the heating water loop pump (see Figure 3-14 and accompanying results, particularly the stable water flow rate in Figure 3-15a), and even at very low flow rates (see Figures 3-5a and 3-16a for the terminal reheat application, and Figure 6-8a for the chilled water cooling coil application). In contrast, the conventional globe valve was unable to provide stable flow at low flow rates and instead cycled between closed and slightly open at low flow rates (see Figures 3-5b and 3-16b for the terminal reheat application, and Figure 6-8b for the chilled water cooling coil application), with resultant temperature responses that also cycled (see Figures 3-6b, 3-17b and Figure 6-9b). For the globe valves, the control performance deteriorated as the valve size increased and the valve authority decreased.

Decreased start-up time (i.e., time required to bring the temperature in all rooms up to the occupied heating setpoint from night setback conditions) resulting from the prevention of overflow and underflow to individual terminal reheat coils

There was no difference observed in the start-up time between the system equipped with PICCV for the terminal reheat valves and the system equipped with conventional globe valves. This may be due in part to the small test system and the fact that the test system is a reverse return system. Plots of the room temperatures for the two systems are provided in Figure 4-3 and the corresponding heating water flow rates to the rooms are shown in Figure 4-4.

Reduction in pumping costs

Terminal Reheat Application: When the heating water loop pumps were controlled to maintain equivalent differential pressure setpoints between the supply and return mains, the pumping energy use of the system equipped with PICCVs was approximately equal to that of the system equipped with conventional globe valves. Although a reduction in water flow rate was seen at low loads in the system with PICCVs, the reduction was small and did not produce measurable pumping energy savings. This may be due in part to the small test system and the fact that the test system is a reverse return system. A comparison of the system heating water flow rate and heating water loop pumping power is shown in Figure 4-6. Chilled Water Cooling Coil Application: Although the Belimo PICCV demonstrated more stable control than the Siemens valve and produced slightly higher temperature rises across the cooling coil at low load conditions, any pumping energy savings resulting from the improved control performance was indistinguishable. A comparison of the pumping energy use is shown in Figure 6-17.

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Increased water-side temperature differential across the terminal reheat coil and AHU chilled water cooling coil, and resulting effect on boiler and chiller efficiency

Terminal Reheat Application: At low loads, the system equipped with PICCVs had heating water temperature drops across the reheat coils of the perimeter rooms that were 5 to 9ºF (2.8 to 5ºC) higher than the system with globe valves. It was not possible to measure any improvement in the boiler efficiency because the system performance of the PICCVs and globe valves was evaluated simultaneously and the heating water loops on the two systems was served by a common boiler. Chilled Water Cooling Coil Application: At low loads, the AHU equipped with the PICCV generally had a slightly higher chilled water temperature rise across the cooling coil on average than the AHU equipped with the globe valve. The temperature rise across each coil is plotted in Figure 6-15 for CL 5.1 and CL 5.2. The difference in the temperature rise is approximately 1 to 2ºF (0.56 to 1.11ºC) at low loads (the second half of the test). It was not possible to measure any improvement in the chiller efficiency because the performance of the PICCV and globe valve was evaluated simultaneously and the chilled water loops on the two AHUs was served by a common chiller.

Automatic, dynamic system balancing, particularly at low loads

This characteristic actually produces the three previous characteristics (i.e., decreased start-up time, reduced pumping costs, and increased water-side temperature differential), although the start-up time phenomenon is associated with high loads, whereas the pumping cost savings and increased temperature differential are expected to be more pronounced at low loads. The increased temperature differential was observed in this testing, but the other two characteristics were not.

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Table of Contents Table of Contents......................................................................................................................... viii List of Figures ................................................................................................................................. x List of Tables ............................................................................................................................... xiv 1 Introduction............................................................................................................................... 1

1.1 Objective .......................................................................................................................... 1 1.2 Scope................................................................................................................................ 1 1.3 Test Facility ..................................................................................................................... 3

2 Terminal Reheat Open Loop Test............................................................................................. 5

2.1 Test Valves....................................................................................................................... 5 2.2 Test Set-Up ...................................................................................................................... 5 2.3 Test Conditions and Procedure ........................................................................................ 7 2.4 Instrumentation ................................................................................................................ 7 2.5 Results.............................................................................................................................. 8 2.6 Conclusions.................................................................................................................... 13

3 Terminal Reheat Closed Loop Test – Effect of Valve Sizing on Valve Performance ........... 14

3.1 Test Units ....................................................................................................................... 14 3.2 Test Set-Up .................................................................................................................... 14

3.2.1 Room Temperature Control with Fixed Inlet Pressure to Control Valve .......... 14 3.2.2 Discharge Air Temperature Control with Fixed Inlet Pressure to Control

Valve .................................................................................................................. 18 3.2.3 Room Temperature Control with Variable Inlet Pressure to Control Valve ..... 19

3.3 Test Conditions and Procedure ...................................................................................... 19 3.4 Instrumentation .............................................................................................................. 21 3.5 Results............................................................................................................................ 21 3.6 Conclusions.................................................................................................................... 32

4 Terminal Reheat Closed Loop Test – System Performance Test ........................................... 33

4.1 Test Units ....................................................................................................................... 33 4.2 Test Set-Up .................................................................................................................... 33 4.3 Test Conditions and Procedure ...................................................................................... 36 4.4 Instrumentation .............................................................................................................. 37 4.5 Results............................................................................................................................ 37 4.6 Conclusions.................................................................................................................... 45

5 Air-Handling Unit Chilled Water Open Loop Test ................................................................ 47

5.1 Test Units ....................................................................................................................... 47 5.2 Test Set-Up .................................................................................................................... 47 5.3 Test Conditions and Procedure ...................................................................................... 49

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5.4 Instrumentation .............................................................................................................. 49 5.5 Results............................................................................................................................ 50 5.6 Conclusions.................................................................................................................... 53

6 Air-Handling Unit Chilled Water Closed Loop Test – Control Performance ........................ 54

6.1 Test Units ....................................................................................................................... 54 6.2 Test Set-Up .................................................................................................................... 54 6.3 Test Conditions and Procedure ...................................................................................... 55 6.4 Instrumentation .............................................................................................................. 56 6.5 Results............................................................................................................................ 56 6.6 Conclusions.................................................................................................................... 63

A. Appendix A: Test Suite 2 Results.......................................................................................... 65

A.1. Plotted Results for CL 2.1.............................................................................................. 65 A.2. Plotted Results for CL 2.2.............................................................................................. 68 A.3. Plotted Results for CL 2.3.............................................................................................. 71 A.4. Plotted Results for CL 2.4.............................................................................................. 74 A.5. Plotted Results for CL 2.5.............................................................................................. 77 A.6. Plotted Results for CL 2.6.............................................................................................. 80 A.7. Plotted Results for CL 2.7.............................................................................................. 83

B. Appendix B: Test Suite 3 Results .......................................................................................... 86

B.1. Tabulated Results for CL 3.1 ......................................................................................... 86 B.2. Tabulated Results for CL 3.2 ......................................................................................... 90 B.3. Tabulated Results for CL 3.3 ......................................................................................... 93

C. Appendix C: Test Suite 5 Results .......................................................................................... 95

C.1. Plotted Results for CL 5.1.............................................................................................. 95 C.2. Plotted Results for CL 5.2.............................................................................................. 99

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List of Figures Figure 1-1: Schematic of the side-by-side test rooms of the Energy Resource Station............. 3 Figure 2-1: Schematic of heating water Loop-A and instrumentation setup for Test Suite 1. .. 6 Figure 2-2: Flow rate through the Belimo PICCV as a function of differential pressure

and commanded signal to the valve. ....................................................................... 8 Figure 2-3: Relationship between the commanded and scaled feedback signals for the

Belimo PICCV. ....................................................................................................... 9 Figure 2-4: Flow rate through the Siemens Powermite MT globe valve as a function of

differential pressure and commanded signal to the valve. .................................... 11 Figure 2-5: Relationship between the commanded and scaled feedback signals for the

Siemens Powermite MT globe valve. The unscaled feedback signal ranges from 0.2 to 103.98% closed. The scaled feedback signal ranges from 0 to 100% open. ........................................................................................................... 12

Figure 2-6: Flow rate through the Belimo PICCV and Siemens Powermite MT globe valve as a function of the scaled valve feedback signal at a differential pressure of 5 psi (34.5 kPa)................................................................................... 12

Figure 3-1: Schematic of heating water Loop-A and Loop-B and instrumentation setup for Test Suite 2. ........................................................................................... 16

Figure 3-2: Typical control sequence at the ERS for a pressure- independent VAV box with hydronic reheat. ..................................................................................... 20

Figure 3-3: Room airflow setpoint and room temperature setpoint schedules for CL 2.1, CL 2.2 and CL 2.3................................................................................................. 24

Figure 3-4: Valve position feedback signal for CL 2.2. .......................................................... 25 Figure 3-5: Heating water flow rate for CL 2.2. ...................................................................... 25 Figure 3-6: Room temperature control for CL 2.2................................................................... 26 Figure 3-7: Room airflow control for CL 2.2. ......................................................................... 26 Figure 3-8: Inlet pressure to control valves for CL 2.2. .......................................................... 26 Figure 3-9: Entering air temperature to reheat coil for CL 2.2................................................ 26 Figure 3-10: Accumulated room temperature error for CL 2.2. ................................................ 27 Figure 3-11: Accumulated actuator travel for CL 2.2. .............................................................. 27 Figure 3-12: Accumulated starts and stops for CL 2.2. ............................................................. 27 Figure 3-13: Accumulated reversals for CL 2.2. ....................................................................... 27 Figure 3-14: Inlet pressure to control valves for CL 2.4. .......................................................... 28 Figure 3-15: Valve position feedback signal for CL 2.4. .......................................................... 28 Figure 3-16: Heating water flow rate for CL 2.4. ...................................................................... 29 Figure 3-17: Discharge air temperature control for CL 2.4. ...................................................... 30 Figure 3-18: Accumulated discharge air temperature error for CL 2.4. .................................... 30 Figure 3-19: Accumulated actuator travel for CL 2.4. .............................................................. 30 Figure 3-20: Accumulated starts and stops for CL 2.4. ............................................................. 30 Figure 3-21: Accumulated reversals for CL 2.4. ....................................................................... 30 Figure 4-1: Schematic of heating water Loop-A and Loop-B and instrumentation setup for

Test Suite 3. .......................................................................................................... 35 Figure 4-2: Pumping performance for January 18, 2005 (CL 3.1). ......................................... 41 Figure 4-3: Room temperature control for January 18, 2005 (CL 3.1) ................................... 42

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Figure 4-4: Heating water flow rate for January 18, 2005 (CL 3.1)........................................ 43 Figure 4-5: Cumulative change in heating water flow rate for January 18, 2005 (CL 3.1)..... 43 Figure 4-6: Pumping performance for February 6, 2005 (CL 3.3). ......................................... 43 Figure 5-1: Schematic of chilled water loop and instrumentation setup for Test Suite 4........ 48 Figure 5-2: Flow rate through the Belimo PICCV as a function of differential pressure

and commanded signal to the valve. ..................................................................... 50 Figure 5-3: Flow rate through the Siemens Powermite MT globe valve as a function of

differential pressure and commanded signal to the valve. .................................... 51 Figure 5-4: Flow rate through the Belimo PICCV and Siemens Powermite MT globe

valve as a function of the scaled valve feedback signal at a differential pressure of 7 psi (48.3 kPa)................................................................................... 52

Figure 6-1: Schematic of chilled water system and instrumentation setup for Test Suite 5.... 55 Figure 6-2: Supply air temperature setpoint and primary chilled water pump speed

profiles for CL 5.1 and CL 5.2.............................................................................. 56 Figure 6-3: Chilled water cooling coil entering air temperatures for CL 5.1. ......................... 57 Figure 6-4: Airflow rates across the chilled water cooling coils for CL 5.1 ........................... 57 Figure 6-5: Chilled water cooling coil entering water temperatures for CL 5.1. .................... 58 Figure 6-6: Chilled water cooling coil valve control signal for CL 5.1................................... 59 Figure 6-7: Chilled water cooling coil valve feedback signal for CL 5.1. .............................. 59 Figure 6-8: Chilled water flow rate for CL 5.1........................................................................ 59 Figure 6-9: Supply air temperature control for CL 5.1............................................................ 60 Figure 6-10: Accumulated supply air temperature error for CL 5.1.......................................... 60 Figure 6-11: Accumulated actuator travel for CL 5.1. .............................................................. 60 Figure 6-12: Accumulated starts and stops for CL 5.1. ............................................................. 60 Figure 6-13: Accumulated reversals for CL 5.1. ....................................................................... 60 Figure 6-14: Cumulative change in chilled water flow rate for CL 5.1..................................... 61 Figure 6-15: Temperature rise across the chilled water cooling coil for CL 5.1 and CL 5.2. ... 63 Figure 6-16: Averaged chilled water flow rate for CL 5.1 and CL 5.2. .................................... 64 Figure 6-17: Secondary chilled water pump power for CL 5.1 and CL 5.2. ............................. 64 Figure A-1: Valve control signal for CL 2.1. ............................................................................65 Figure A-2: Valve position feedback signal for CL 2.1. .......................................................... 65 Figure A-3: Heating water flow rate for CL 2.1. ...................................................................... 66 Figure A-4: Room temperature control for CL 2.1................................................................... 66 Figure A-5: Room airflow control for CL 2.1. ......................................................................... 66 Figure A-6: Inlet pressure to valve for CL 2.1. ........................................................................ 67 Figure A-7: Differential pressure across valve for CL 2.1. ...................................................... 67 Figure A-8: Accumulated room temperature error for CL 2.1. ................................................ 67 Figure A-9: Accumulated actuator travel for CL 2.1. .............................................................. 67 Figure A-10: Accumulated starts and stops for CL 2.1. ............................................................. 67 Figure A-11: Accumulated reversals for CL 2.1. ....................................................................... 67 Figure A-12: Valve control signal for CL 2.2. ........................................................................... 68 Figure A-13: Valve position feedback signal for CL 2.2. .......................................................... 68 Figure A-14: Heating water flow rate for CL 2.2. ...................................................................... 69 Figure A-15: Room temperature control for CL 2.2................................................................... 69 Figure A-16: Room airflow control for CL 2.2. ......................................................................... 69 Figure A-17: Inlet pressure to valve for CL 2.2. ........................................................................ 70

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Figure A-18: Differential pressure across valve for CL 2.2. ...................................................... 70 Figure A-19: Accumulated room temperature error for CL 2.2. ................................................ 70 Figure A-20: Accumulated actuator travel for CL 2.2. .............................................................. 70 Figure A-21: Accumulated starts and stops for CL 2.2. ............................................................. 70 Figure A-22: Accumulated reversals for CL 2.2. ....................................................................... 70 Figure A-23: Valve control signal for CL 2.3. ........................................................................... 71 Figure A-24: Valve position feedback signal for CL 2.3. .......................................................... 71 Figure A-25: Heating water flow rate for CL 2.3. ...................................................................... 72 Figure A-26: Room temperature control for CL 2.3................................................................... 72 Figure A-27: Room airflow control for CL 2.3. ......................................................................... 72 Figure A-28: Inlet pressure to valve for CL 2.3. ........................................................................ 73 Figure A-29: Differential pressure across valve for CL 2.3. ...................................................... 73 Figure A-30: Accumulated room temperature error for CL 2.3. ................................................ 73 Figure A-31: Accumulated actuator travel for CL 2.3. .............................................................. 73 Figure A-32: Accumulated starts and stops for CL 2.3. ............................................................. 73 Figure A-33: Accumulated reversals for CL 2.3. ....................................................................... 73 Figure A-34: Valve control signal for CL 2.4. ........................................................................... 74 Figure A-35: Valve position feedback signal for CL 2.4. .......................................................... 74 Figure A-36: Heating water flow rate for CL 2.4. ...................................................................... 75 Figure A-37: Discharge air temperature control for CL 2.4. ...................................................... 75 Figure A-38: Inlet pressure to valve for CL 2.4. ........................................................................ 75 Figure A-39: Differential pressure across valve for CL 2.4. ...................................................... 75 Figure A-40: Accumulated room temperature error for CL 2.4. ................................................ 76 Figure A-41: Accumulated actuator travel for CL 2.4. .............................................................. 76 Figure A-42: Accumulated starts and stops for CL 2.4. ............................................................. 76 Figure A-43: Accumulated reversals for CL 2.4. ....................................................................... 76 Figure A-44: Valve control signal for CL 2.5. ........................................................................... 77 Figure A-45: Valve position feedback signal for CL 2.5. .......................................................... 77 Figure A-46: Heating water flow rate for CL 2.5. ...................................................................... 78 Figure A-47: Discharge air temperature control for CL 2.5. ...................................................... 78 Figure A-48: Inlet pressure to valve for CL 2.5. ........................................................................ 78 Figure A-49: Differential pressure across valve for CL 2.5. ...................................................... 78 Figure A-50: Accumulated room temperature error for CL 2.5. ................................................ 79 Figure A-51: Accumulated actuator travel for CL 2.5. .............................................................. 79 Figure A-52: Accumulated starts and stops for CL 2.5. ............................................................. 79 Figure A-53: Accumulated reversals for CL 2.5. ....................................................................... 79 Figure A-54: Valve control signal for CL 2.6. ........................................................................... 80 Figure A-55: Valve position feedback signal for CL 2.6. .......................................................... 80 Figure A-56: Heating water flow rate for CL 2.6. ...................................................................... 81 Figure A-57: Room temperature control for CL 2.6................................................................... 81 Figure A-58: Room airflow control for CL 2.6. ......................................................................... 81 Figure A-59: Inlet pressure to valve for CL 2.6. ........................................................................ 82 Figure A-60: Differential pressure across valve for CL 2.6. ...................................................... 82 Figure A-61: Accumulated room temperature error for CL 2.6. ................................................ 82 Figure A-62: Accumulated actuator travel for CL 2.6. .............................................................. 82 Figure A-63: Accumulated starts and stops for CL 2.6. ............................................................. 82

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Figure A-64: Accumulated reversals for CL 2.6. ....................................................................... 82 Figure A-65: Valve control signal for CL 2.7. ........................................................................... 83 Figure A-66: Valve position feedback signal for CL 2.7. .......................................................... 83 Figure A-67: Heating water flow rate for CL 2.7. ...................................................................... 84 Figure A-68: Room temperature control for CL 2.7................................................................... 84 Figure A-69: Room airflow control for CL 2.7. ......................................................................... 84 Figure A-70: Inlet pressure to valve for CL 2.7. ........................................................................ 85 Figure A-71: Differential pressure across valve for CL 2.7. ...................................................... 85 Figure A-72: Accumulated room temperature error for CL 2.7. ................................................ 85 Figure A-73: Accumulated actuator travel for CL 2.7. .............................................................. 85 Figure A-74: Accumulated starts and stops for CL 2.7. ............................................................. 85 Figure A-75: Accumulated reversals for CL 2.7. ....................................................................... 85 Figure C-1: Valve control signal for CL 5.1. ........................................................................... 95 Figure C-2: Valve position feedback signal for CL 5.1. .......................................................... 95 Figure C-3: Chilled water flow rate for CL 5.1........................................................................ 96 Figure C-4: Supply air temperature control for CL 5.1............................................................ 96 Figure C-5: Sum of room airflow rates for CL 5.1................................................................... 96 Figure C-6: Temperature rise across cooling coil for CL 5.1................................................... 97 Figure C-7: Inlet pressure to valve for CL 5.1. ....................................................................... 97 Figure C-8: Differential pressure across valve for CL 5.1. ...................................................... 97 Figure C-9: Accumulated supply air temperature error for CL 5.1.......................................... 97 Figure C-10: Accumulated actuator travel for CL 5.1. .............................................................. 97 Figure C-11: Accumulated starts and stops for CL 5.1. ............................................................ 98 Figure C-12: Accumulated reversals for CL 5.1. ....................................................................... 98 Figure C-13: Cumulative change in flow rate for CL 5.1. ......................................................... 98 Figure C-14: Secondary pump power for CL 5.1....................................................................... 98 Figure C-15: Valve control signal for CL 5.2. ........................................................................... 99 Figure C-16: Valve position feedback signal for CL 5.2. .......................................................... 99 Figure C-17: Chilled water flow rate for CL 5.2...................................................................... 100 Figure C-18: Supply air temperature control for CL 5.2.......................................................... 100 Figure C-19: Sum of room airflow rates for CL 5.2................................................................. 100 Figure C-20: Temperature rise across cooling coil for CL 5.2................................................. 101 Figure C-21: Inlet pressure to valve for CL 5.2. ..................................................................... 101 Figure C-22: Differential pressure across valve for CL 5.2. .................................................... 101 Figure C-23: Accumulated supply air temperature error for CL 5.2........................................ 101 Figure C-24: Accumulated actuator travel for CL 5.2. ............................................................ 101 Figure C-25: Accumulated starts and stops for CL 5.2. .......................................................... 102 Figure C-26: Accumulated reversals for CL 5.2. ..................................................................... 102 Figure C-27: Cumulative change in flow rate for CL 5.2. ....................................................... 102 Figure C-28: Secondary pump power for CL 5.2..................................................................... 102

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List of Tables Table 1-1: Summary of tests performed for the VAV terminal reheat application..................... 2 Table 1-2: Summary of tests performed for the AHU chilled water cooling coil application. ... 3 Table 2-1: Specifications for valves used for Test Suite 1.......................................................... 5 Table 3-1: Valve specifications for Test Suite 2. ...................................................................... 15 Table 3-2: Test set-up for room air temperature control with constant inlet pressure

to control valve and variable heating water loop pump speed................................. 17 Table 3-3: Test set-up for discharge air temperature control with constant inlet pressure

to control valve and variable heating water loop pump speed................................. 18 Table 3-4: Test set-up for room air temperature control with variable inlet pressure to

control valve and constant heating water loop pump speed. ................................... 19 Table 3-5: Summary of control performance parameters for Test Suite 2................................ 24 Table 4-1: Valve specifications for Test Suite 3. ...................................................................... 34 Table 4-2: Test set-up for Test Suite 3. ..................................................................................... 37 Table 4-3: Daily average energy use and temperature control characterization for the

occupied period of Test Suite 3. .............................................................................. 40 Table 4-4: Daily average heating water flow control characterization for Test Suite 3............ 40 Table 4-5: Summary of system balancing performance at low loads for CL 3.3. The

A test rooms are served by Belimo PICCV and the B test rooms by Siemens globe valves. ............................................................................................................ 45

Table 5-1: Specifications for valves used for Test Suite 4 and Test Suite 5. ............................ 47 Table 6-1: Summary of control performance parameters for Test Suite 5................................ 62 Table B-1: Daily reheat energy use, cumulative temperature error, and cumulative

change in water flow rate for test rooms East-A and East-B for CL 3.1. .................86 Table B-2: Daily reheat energy use, cumulative temperature error, and cumulative

change in water flow rate for test rooms Interior-A and Interior-B for CL 3.1. ...... 87 Table B-3: Daily reheat energy use, cumulative temperature error, and cumulative

change in water flow rate for test rooms South-A and South-B for CL 3.1. ........... 88 Table B-4: Daily reheat energy use, cumulative temperature error, and cumulative

change in water flow rate for test rooms West-A and West-B for CL 3.1. ............. 89 Table B-5: Daily reheat energy use, cumulative temperature error, and cumulative

change in water flow rate for test rooms East-A and East-B for CL 3.2. ................ 90 Table B-6: Daily reheat energy use, cumulative temperature error, and cumulative


change in water flow rate for test rooms South-A and South-B for CL 3.2. ........... 91 Table B-8: Daily reheat energy use, cumulative temperature error, and cumulative

change in water flow rate for test rooms West-A and West-B for CL 3.2. ............. 92 Table B-9: Daily reheat energy use, cumulative temperature error, and cumulative

change in water flow rate for test rooms East-A and East-B for CL 3.3. ................ 93 Table B-10: Daily reheat energy use, cumulative temperature error, and cumulative


change in water flow rate for test rooms South-A and South-B for CL 3.3. ........... 94

xv

Table B-12: Daily reheat energy use, cumulative temperature error, and cumulative change in water flow rate for test rooms West-A and West-B for CL 3.3. ............. 94

1

1 Introduction 1.1 Objective The objective of the testing described in this report was to evaluate the performance of Belimo pressure independent characterized control valves (PICCV) against conventional globe control valves for terminal reheat and air-handling unit (AHU) chilled water cooling coil applications in a commercial office building. Specifically, testing was performed to verify the performance of the PICCV with respect to the following characteristics:

• Ability to maintain perfect valve authority; • Decreased start-up time (i.e., time required to bring the temperature in all rooms up to the

occupied heating setpoint from night setback conditions) resulting from the prevention of overflow and underflow to individual terminal reheat coils;

• Reduction in pumping costs; • Increased water-side temperature differential across the terminal reheat coil and AHU

chilled water cooling coil, and resulting effect on boiler efficiency; and • Automatic, dynamic system balancing, particularly at low loads.

1.2 Scope This report describes the results of a series of tests undertaken to evaluate the performance of the Belimo PICCV in comparison to a conventional globe valve. Tests were performed for a variable-air-volume (VAV) terminal reheat application and an AHU chilled water cooling coil application. The tests consisted of the following:

1. Terminal Reheat Open Loop Test: The purpose of this test was to quantify the water flow rate through the terminal reheat test valves as a function of valve position (i.e., % open) and the differential pressure across the valves.

2. Terminal Reheat Closed Loop Test – Effect of Valve Sizing on Valve Performance: The purpose of this test was to evaluate the control performance of the PICCV in comparison to a correctly sized and two oversized conventional globe valves for a terminal reheat application.

3. Terminal Reheat Closed Loop Test – System Performance Test: The purpose of this test was to compare energy use, control stability, start-up time and other relevant performance characteristics as the test valves were utilized under normal system operating conditions for a terminal reheat application.

4. AHU Chilled Water Open Loop Test: The purpose of this test was to quantify the water flow rate through the AHU chilled water cooling coil test valves as a function of valve position (i.e., % open) and the differential pressure across the valves.

5. AHU Chilled Water Closed Loop Test – Control Performance: The purpose of this test was to evaluate the control performance of the PICCV in comparison to a correctly sized conventional globe valve for an AHU chilled water cooling coil application.

Summaries of the tests are provided for reference in Table 1-1 and Table 1-2.

2

Table 1-1: Summary of tests performed for the VAV terminal reheat application.

Test Description Test Number

System A Test Room Configuration

System B Test Room Configuration

OL 1.1 Belimo PICCV-15-003 Not used Open-loop test to determine flow rate through test valve as a function of the

differential pressure across the valve and the degree to which the valve is open.

Tests performed in South A Test Room. OL 1.2 Correctly sized globe valve:

Siemens Powermite MT 599-02036 (Cv = 1.6)

Not used

CL 2.1 Belimo PICCV-15-003

Correctly sized globe valve: Siemens Powermite

MT 599-02036 (Cv = 1.6)


Oversized globe valve: Siemens Powermite

MT 599-02038 (Cv = 2.5)

Closed-loop room air temperature control with constant inlet pressure to control valve and variable heating water loop

pump speed. Tests performed in South A and South B Test Rooms.


Very oversized globe valve: Siemens Powermite

MT 599-02041 (Cv = 4.0)

CL 2.4 Correctly sized globe valve:


Belimo PICCV-15-003 Closed-loop discharge air temperature control with constant inlet pressure to

control valve and variable heating water loop pump speed. Tests performed in

South A and South B Test Rooms. CL 2.5 Belimo PICCV-15-003 Correctly sized globe valve:


CL 2.6 Correctly sized globe valve:


Belimo PICCV-15-003 Closed-loop room air temperature control with variable inlet pressure to control valve and constant heating water loop

pump speed. Tests performed in South A and South B Test Rooms. CL 2.7

Very oversized globe valve: Siemens Powermite

MT 599-02041 (Cv = 4.0) Belimo PICCV-15-003

Closed-loop system comparison under normal operation with PICCV installed in

one system and correctly sized globe valves installed in second system. Tests

performed using all test rooms for System A and System B.

CL 3.1

Perimeter Rooms: Belimo PICCV-15-003

Interior Room: Belimo PICCV-15-001+

Perimeter Rooms: Siemens Powermite MT 599-02036

Interior Room: Siemens Powermite MT 599-02032

Same as CL 3.1, except PICCVs are installed in System B and globe valves

are installed in System A. Tests performed using all test rooms for

System A and System B.

CL 3.2





Same as CL 3.1, except the differential pressure setpoint (used to control the

heating water loop pump) between the supply and return lines for the heating

water loop is the same for both systems, whereas in CL 3.1 and CL 3.2 it was not. Tests performed using all test rooms for

System A and System B.

CL 3.3





3

Table 1-2: Summary of tests performed for the AHU chilled water cooling coil application.

Test Description Test Number

AHU-A Chilled Water Cooling Coil Set-up

AHU-B Chilled Water Cooling Coil Set-up

OL 4.1 Belimo PICCV-32-026-PT Not used Open-loop test to determine flow rate through test valve as a function of the

differential pressure across the valve and the degree to which the valve is open. Tests performed using AHU-A chilled

water cooling coil. OL 4.2


MT 599-02046 (Cv = 10.0) Not used

CL 5.1 Belimo PICCV-32-026-PT


MT 599-02046 (Cv = 10.0) Closed-loop supply air temperature

control with a variable inlet pressure to control valve. Tests performed using

chilled water cooling coils for AHU-A and AHU-B.

CL 5.2


MT 599-02046 (Cv = 10.0) Belimo PICCV-32-026-PT

1.3 Test Facility Testing was performed at the Iowa Energy Center, Energy Resource Station (ERS). A schematic of the facility is shown in Figure 1-1. The facility consists of four matched pairs (“A” and “B”) of test rooms facing east, south, west and in the interior. Side A of each test room pair is isolated from side B and is served by a separate heating, ventilating and air-conditioning system. The

Figure 1-1: Schematic of the side-by-side test rooms of the Energy Resource Station.

4

paired rooms are identical in their construction and heating and cooling loads. This design enables side-by-side comparisons of the systems and/or the algorithms that control them. Additional information on the ERS, including an online virtual tour of the facility, can be viewed at the following web site: http://www.energy.iastate.edu/ers/.

5

2 Terminal Reheat Open Loop Test The purpose of this suite of tests, which is designated Test Suite 1, was to evaluate the pressure independent feature of the Belimo PICCV. The test consisted of measuring the water flow rate through the test valve as a function of valve position and pressure drop across the valve for a VAV terminal reheat application.

2.1 Test Valves Testing compared the performance of one Belimo PICCV and one correctly sized Siemens Powermite MT series globe valve and actuator assembly. The selection of the valves was based on the design flow rate of the terminal reheat coil of an exterior room in the ERS. This design flow rate is 3 GPM (0.19 L/s). The globe valve was sized to produce a pressure drop of 4 psi (27.6 kPa) with the valve wide open. Detailed specifications for the valve and actuator assemblies are provided in Table 2-1.

Table 2-1: Specifications for valves used for Test Suite 1.

Designation Belimo PICCV Siemens Powermite MT

Manufacturer Belimo Siemens Model PICCV-15-003 Powermite MT 599-02036 Type PICCV Globe (Stroke 7/32") Line Size 1/2 " 1/2 " Cv N/A 1.6 Design Flow Rate 3 GPM (0.19 L/s) N/A

Valve

Close-Off Pressure 200 PSI (1379 kPa) 160 PSI (1103 kPa) Manufacturer Belimo Siemens

Model LR24-MFT US+NO+P-10028 SQS65U 264-02036

Type Fail-in-Place, DA/RA (adjustable) Fail-in-Place, RA

Force 35 in-lbf (4 N-m) min. torque 90 lbf (400 N)

Run-Time 100 seconds 30 second Input Signal 0 - 10 VDC 0 - 10 VDC Feedback Output 0 - 10 VDC 0 - 10 VDC

Actuator

Power 24VAC±20%, 24VDC±10% 24VAC, +20%, -15%

The valves are normally open and the actuators do not have spring return.

2.2 Test Set-Up The test valve was installed on the return side of the reheat coil in the South-A test room as shown in Figure 2-1. An Endress Hauser model Cerabar M PMC 41 single-point pressure

6

HeatingWaterBoiler

F

A

C VFD

Interior ATest Room

East ATest Room

South ATest Room

West ATest Room

Test valve:- Belimo PICCV- CGCV

P1

DP

HC

TT

F

A

HC

TT

F

AExisting valveCLOSED

HC

TT

F

A

HC

TT

Existing valveCLOSED


VFD

LEGEND

A

F

P

DP

- Pressure Independent Characterized Control Valve

- Conventional Globe Control Valve

- Actuator (Analog)

- Flow Meter

- Temperature Sensor

- Pressure Sensor

- Differential Pressure Sensor

- Variable Frequency Drive

- Controller

PICCV

CGCV

T

C

Figure 2-1: Schematic of heating water Loop-A and instrumentation setup for Test Suite 1.

transducer (0 – 100 psig [0 - 689.5 kPa] calibrated span; accuracy of ±0.2 % of calibrated span) was used to measure the valve inlet pressure. An Endress Hauser model Deltabar S PMD 235 differential pressure transducer (0 – 43 psig [0 – 296.5 kPa] calibrated span; accuracy of ±0.1 % of calibrated span) was used to measure the pressure drop across the valve. The water flow rate was measured using a Badger Meter model MagnetoflowTM electromagnetic flow meter (0.1 – 33 fps [0.03 - 10.06 m/s]; accuracy of ±0.25% of flow rate). The reheat coil in South-A (and all other perimeter test rooms) is a single-row plate fin type coil with a design water flow rate of 3 GPM (0.19 L/s) and a design water pressure drop through the coil of 1.4 ft. of water (4.19 kPa). Two pumps were used to achieve the desired pressure drop across the test valve for each test condition. The Loop-A heating water pump is normally used to circulate water to the VAV

7

terminal reheat coils. A second pump, designated the booster pump, was installed to enable higher pressures to be achieved. The speed of each pump was controlled via a variable frequency drive. To minimize pressure disturbances during testing, the reheat coil valves for the remaining three test rooms on Loop-A (East-A, West-A and Interior-A) were overridden to remain closed for the duration of the test.

2.3 Test Conditions and Procedure The first test was performed on the Belimo PICCV on November 24, 2004. The valve was tested at all combinations of the following conditions:

Commanded Signal to Valve: 10, 15, 20, 25, 30, 35, 40, 60, 80, 100, and 40% open (20% open corresponds to a commanded signal to the valve of 2 VDC for a 0 to 10 VDC output range)

Differential Pressure Across Valve: 5, 10, 15, 20, and 30 psi (34.5, 69, 103.4, 137.9, and

206.9 kPa); achieved by adjusting the speeds of the circulating and booster pumps for Loop-A

The initial test point was a commanded signal of 10% open and a differential pressure across the valve of 5 psi (34.5 kPa). The commanded signal was then increased to the next test condition (i.e., 15% open) while the differential pressure was held constant. Conditions were typically allowed to stabilize for three to five minutes between test points. Testing continued in this way until the commanded signal was 100% open. The final test point at a given differential pressure was a commanded signal of 40% open. This point was recorded to enable the test valve hysteresis to be evaluated. The procedure was then repeated at differential pressures of 10, 15, 20, and 30 psi (69, 103.4, 137.9, and 206.9 kPa). After completing the test of the Belimo PICCV, the Siemens Powermite MT globe valve was installed in its place and the test procedure repeated on November 28-29, 2004. The two tests were designated as follows: OL1.1 – Belimo PICCV OL1.2 – Siemens Powermite MT

2.4 Instrumentation The following list of measurement and control points were monitored and recorded during the test:

1. Inlet pressure to test valve (psig); note that throughout this report, inlet pressures are measured relative to atmospheric pressure

2. Differential pressure across the test valve (psi) 3. Water flow rate (gallons per minute) 4. Commanded signal to test valve (% open) 5. Valve position feedback (% open) 6. Heating water pump speed (% of maximum or Hz) 7. Reheat coil entering water temperature (°F) 8. Reheat coil leaving water temperature (i.e., temperature at the valve, °F)

8

Each of these eight points was recorded at 10 second intervals using a National Instruments data acquisition system.

2.5 Results The water flow rate through the Belimo PICCV as a function of the differential pressure across the valve and the commanded (or input) signal to the valve is shown in Figure 2-2. The commanded signal has units of “% open”; for example, 35% open corresponds to a commanded signal of 3.5 VDC. The data points in Figure 2-2 and subsequent figures in this chapter are one minute averages obtained from the 10 second data. The curves in Figure 2-2 indicate that the flow rate through the Belimo PICCV is nearly independent of the differential pressure across the valve for a given commanded signal to the valve. At the design condition (i.e., commanded signal of 100% open), the flow rate varies from 3.12 GPM at 5 psi to 3.19 GPM at 30 psi (0.197 L/s at 34.5 kPa to 0.201 L/s at 206.9 kPa). The maximum flow rate over this pressure range is 3.21 GPM at 15 psi (0.203 L/s at 103.4 kPa). In general, the flow rate varies by less than 0.11 GPM (0.007 L/s) over the range of pressures tested for a given commanded signal. The only exception occurs at a commanded signal of 40% open, where the variation in flow rate is slightly greater. Figure 2-2 contains two curves corresponding to a commanded signal of 40% open. The first curve corresponds to data obtained with the commanded signal increasing from 35% open to

Differential Pressure Across Valve (psi)

0 5 10 15 20 25 30 35

Hea

ting

Wat

er F

low

Rat

e (G

PM)

0.0

0.5

1.0

1.5

2.0

2.5

3.0

3.5

Hea

ting

Wat

er F

low

Rat

e (L

/s)

0.00

0.02

0.04

0.06

0.08

0.10

0.12

0.14

0.16

0.18

0.20

0.22

Differential Pressure Across Valve (kPa)

0 20 40 60 80 100 120 140 160 180 200 220 240

hysteresis data

10% open15% open20% open25% open30% open 35% open40% open 60% open 80% open 100% open40% open

Figure 2-2: Flow rate through the Belimo PICCV as a function of differential pressure and

commanded signal to the valve.

9

40% open and the second curve (labeled hysteresis data) corresponds to data obtained with the commanded signal decreasing from 100% open to 40% open. The flow rates are significantly different for the two curves (0.28 to 0.43 GPM [0.018 to 0.027 L/s] for the first curve and 0.45 to 0.65 GPM [0.028 to 0.041 L/s] for the second curve). Based on the feedback signal from the actuator, a commanded signal results in consistent positioning of the valve (i.e., the position feedback corresponding to a commanded signal of 35% open is 43.8% open, independent of the differential pressure across the valve). The relationship between the commanded signal and the feedback signal is shown in Figure 2-3. The feedback signal has been scaled to range from 0 to 100% open. The unscaled feedback ranges from approximately 4.9 to 73% open. Note in Figure 2-3 that there are five data points corresponding to five differential pressures for each commanded signal. The only exception is a commanded signal of 40% open, which has ten data points. Because they overlap one another, multiple data points appear to be a single point in Figure 2-3. The data in Figure 2-3 indicates that the hysteresis observed in the data in Figure 2-2 is not due to inconsistent positioning of the control valve. With this assumption, the most likely source of the hysteresis is the pressure regulator device in the PICCV, which must respond to pressure changes that occur as the valve is opened and closed. Although some hysteresis is observed, it could be argued that it is unimportant because a feedback application will simply reposition the valve as necessary to achieve the desired process condition.

Valve Commanded Signal (% Open)

0 10 20 30 40 50 60 70 80 90 100

Sca

led

Val

ve F

eedb

ack

Sig

nal (

% O

pen)

0

10

20

30

40

50

60

70

80

90

100

Figure 2-3: Relationship between the commanded and scaled feedback signals for the Belimo PICCV.

10

The performance of the valve is consistent with Belimo literature on the PICCV. Although some slight pressure dependencies can be observed in the data (the flow rate increases slightly at higher differential pressures), the variations are less than 6.5% of the design flow of 3 GPM (0.19 L/s). The water flow rate through the Siemens Powermite MT globe valve as a function of the differential pressure across the valve and the commanded signal to the valve is shown in Figure 2-4. The commanded signal again has units of “% open” and 35% open corresponds to a commanded signal of 3.5 VDC. Figure 2-4 consists of data obtained with the balancing valve 42% closed (solid lines) as well as data obtained with the balancing valve fully open (dashed lines). Because the balancing valve is located upstream of locations where the inlet pressure and differential pressure measurements are made, the balancing valve will not affect the flow rate through the control valve at a specific differential pressure and valve position. Partially closing the balancing valve will, however, limit the ability of the pumps to achieve high differential pressures when the valve is fully open or nearly fully open. Specifically, the pumps were unable to provide enough head to produce the higher pressure drops when the Siemens valve was 80% open (20 and 30 psi [137.9 and 206.9 kPa] could not be achieved) and 100% open (15, 20 and 30 psi [103.4, 137.9 and 206.9 kPa] could not be achieved) and the balancing valve was 42% closed. As a consequence, these curves are incomplete. The missing data points were obtained through retesting with the balancing valve 100% open. Additional data points were also collected with the balancing valve 100% open (dashed curves in Figure 2-4) to demonstrate that the balancing valve does not influence the flow rate at a specific differential pressure and commanded signal to the valve. This assertion is borne out by the data. The curves in Figure 2-4 indicate that the flow rate through the Siemens valve increases as the differential pressure across the valve increases for a fixed commanded signal to the valve. This is consistent with Siemens literature on the Powermite MT series valve. The flow rates measured when the valve was fully open are 13 to 15% higher than expected based on Siemens literature. For example, for a differential pressure of 5 psi (34.5 kPa), a flow rate of 4.14 GPM (0.261 L/s) was measured and for a differential pressure of 10 psi (69 kPa), a flow rate of 5.76 GPM (0.363 L/s) was measured. The Siemens literature indicates the flow rates should be approximately 3.6 GPM at 5 psi and 5.1 GPM at 10 psi (0.227 L/s at 34.5 kPa and 0.322 L/s at 69 kPa). Based on the measured flow rates, the Siemens valve has a flow coefficient (Cv) of approximately 1.82, whereas the manufacturer stated flow coefficient is 1.6. It was noted in Section 2.1 that the globe valve was sized to produce a 4 psi (27.6 kPa) pressure drop across the valve when it is fully open. This sizing practice is common in the field and the calculated flow coefficient based on this criteria is Cv = 1.5. The Siemens Powermite MT 599-02036, with a flow coefficient of 1.6, was closest to the desired value of Cv = 1.5. ASHRAE sizing criteria, which states that the control valve pressure drop should be at least 25 to 50 percent of the system loop pressure drop, suggests a valve with a flow coefficient of Cv = 1.14 is appropriate for this application. Thus, based on actual performance, the “correctly sized” conventional globe valve was 21 to 60% oversized depending on which of these two criteria are used for selection.

11


0 5 10 15 20 25 30 35

Hea

ting

Wat

er F

low

Rat

e (G

PM)

0

1

2

3

4

5

6

7

8

9

10

11

Hea

ting

Wat

er F

low

Rat

e (L

/s)

0.0

0.1

0.2

0.3

0.4

0.5

0.6


0 20 40 60 80 100 120 140 160 180 200 220 240

10% open15% open20% open25% open30% open 35% open40% open 60% open 80% open 100% open40% open10% open * 40% open * 80% open * 100% open *

* balancing valve 100% open

hysteresisdata

Figure 2-4: Flow rate through the Siemens Powermite MT globe valve as a function of differential pressure and commanded signal to the valve.

The Siemens globe valve was tested for hysteresis in the same manner as the Belimo PICCV. At 5 psi (34.5 kPa), a flow rate of 1.12 GPM (0.071 L/s) was obtained with the valve position increasing and a flow rate of 1.08 GPM (0.068 L/s) was obtained with the valve position decreasing. At 30 psi (206.9 kPa), a flow rate of 2.74 GPM (0.173 L/s) was obtained with the valve position increasing and a flow rate of 2.64 GPM (0.167 L/s) was obtained with the valve position decreasing. Thus, the Siemens valve displays very little hysteresis. A comparison of the scaled feedback signal to the commanded input signal is shown in Figure 2-5. These data indicate a commanded signal results in consistent positioning of the valve. Figure 2-6 shows a comparison of the flow rate through the Belimo PICCV and Siemens globe valve as a function of the feedback signal from each valve at a differential pressure of 5 psi (34.5 kPa). This plot shows that the Belimo valve has the characteristic of an equal percentage valve whereas the Siemens valve demonstrates a nearly linear flow characteristic. The Siemens literature refers to the valve characteristic as a modified equal percentage characteristic.

12

Valve Commanded Signal (% Open)

0 10 20 30 40 50 60 70 80 90 100

Sca

led

Val

ve F

eedb

ack

Sig

nal (

% O

pen)

0

10

20

30

40

50

60

70

80

90

100

Figure 2-5: Relationship between the commanded and scaled feedback signals for the Siemens Powermite MT globe valve. The unscaled feedback signal ranges from 0.2 to 103.98% closed.

The scaled feedback signal ranges from 0 to 100% open.

Scaled Valve Feedback Signal (% Open)

0 10 20 30 40 50 60 70 80 90 100

Hea

ting

Wat

er F

low

Rat

e (G

PM)

0

1

2

3

4

5H

eatin

g W

ater

Flo

w R

ate

(L/s

)

0.00

0.05

0.10

0.15

0.20

0.25

0.30

Globe Valve

PICCV

Figure 2-6: Flow rate through the Belimo PICCV and Siemens Powermite MT globe valve as a function of the scaled valve feedback signal at a differential pressure of 5 psi (34.5 kPa).

13

2.6 Conclusions Open-loop tests were conducted to quantify the water flow rate through a Belimo PICCV-15-003 and a correctly sized Siemens Powermite MT 599-02036 globe valve as a function of differential pressure across the valve and the commanded signal to the valve. Consistent with the manufacturer’s literature, for a differential pressure range of 5 to 30 psi (34.5 to 206.8 kPa), the flow rate through the Belimo PICCV was nearly independent of differential pressure for a fixed valve position. As expected, the flow rate through the Siemens valve increased as the differential pressure increased for a fixed valve position; however, the flow rate though the Siemens valve with the valve fully open was 13 to 15% higher than expected based on the manufacturer’s literature. Furthermore, the valve is oversized by approximately 21% based on sizing that is intended to produce a 4 psi pressure drop at the design flow of 3 GPM (0.19 L/s), and the valve is oversized by approximately 60% based on ASHRAE sizing criteria. Testing also revealed that the Belimo valve has an equal percentage characteristic curve, while the Siemens valve has a nearly linear characteristic curve.

14

3 Terminal Reheat Closed Loop Test – Effect of Valve Sizing on Valve Performance

The purpose of this suite of tests, which is designated Test Suite 2, was to compare the control performance of the Belimo PICCV to three conventional globe valves, each having a different flow coefficient (Cv), for a VAV terminal reheat application. The conventional globe valves were from the Siemens Powermite MT valve series and consisted of one correctly sized valve (the same valve used in the open-loop tests described in Chapter 2) and two oversized valves. The tests consisted of evaluating control characteristics, such as stability and ability to maintain the room or discharge air temperature at setpoint, as scheduled disturbances were imposed on the process being controlled.

3.1 Test Units Testing compared the performance of one Belimo PICCV and three Siemens Powermite MT series globe valve and actuator assemblies. The three Siemens valves consisted of one correctly sized valve with a Cv equal to 1.6, and two oversized valves, with flow coefficients equal to 2.5 and 4, respectively. The selection of the correctly sized valve (Cv = 1.6) was based on the design flow rate of the terminal reheat coil of an exterior room in the Energy Resource Station. This design flow rate is 3 GPM (0.19 L/s). Detailed specifications for the valve and actuator assemblies are listed in Table 3-1.

3.2 Test Set-Up Figure 3-1 is a schematic of the test set-up for Test Suite 2. The Belimo PICCV and Siemens globe valves were installed and tested simultaneously on the return side of the reheat coils in the South-A and South-B test rooms. Endress Hauser model Cerabar M PMC 41 single-point pressure transducers were used to measure the inlet pressure to each valve. Endress Hauser model Deltabar S PMD 235 differential pressure transducers were used to measure the pressure drop across each valve. Specifications for the Endress Hauser pressure transducers are provided in Section 2.2. The water flow rates were measured using Badger Meter model MagnetoflowTM electromagnetic flow meters (0.1 – 33 fps [0.03 - 10.06 m/s]; accuracy of ±0.25% of flow rate). Test Suite 2 consists of three sets of tests that are described in subsequent sections. Throughout all the tests, the balancing valves on the test rooms were 100% open. In addition, to minimize the effect of thermal stratification in the test rooms, a single diffuser was used and a box fan was attached to the ceiling of each test room and operated on high speed to promote mixing.

3.2.1 Room Temperature Control with Fixed Inlet Pressure to Control Valve The first set of tests compared the performance of the test valves for a room temperature control application in which the inlet pressure to the control valve was controlled to a fixed setpoint. Three tests, designated CL 2.1, CL 2.2, and CL 2.3 were conducted. Key differences among the tests are summarized in Table 3-2. In each test the speed of the heating water loop pump was controlled via a variable frequency drive to maintain a fixed inlet pressure to the test valve. The strategy for determining the inlet pressure setpoint for each test follows:

15

Table 3-1: Valve specifications for Test Suite 2.

Designation Belimo PICCV Siemens Powermite MT

Siemens Powermite MT

Siemens Powermite MT

Manufacturer Belimo Siemens Siemens Siemens

Model PICCV-15-003 Powermite MT 599-02036

Powermite MT 599-02038


Type PICCV Globe (Stroke 7/32")

Globe (Stroke 7/32")


Line Size 1/2 " 1/2 " 1/2 " 1/2 " Cv N/A 1.6 2.5 4 Design Flow Rate 3 GPM (0.19 L/s) N/A N/A N/A

Valve

Close-Off Pressure 200 PSI (1379 kPa) 160 psi (1103 kPa) 85 psi (586 kPa) 85 psi (586 kPa) Manufacturer Belimo Siemens Siemens Siemens

Model LR24-MFT US+NO+P-10028 SQS65U 264-02036 SQS65U 264-02038 SQS65U 264-02041

Type Fail-in-Place, DA/RA (adjustable) Fail-in-Place, RA Fail-in-Place, RA Fail-in-Place, RA

Force 35 in-lbf (4 N-m) min. torque 90 lbf (400 N) 90 lbf (400 N) 90 lbf (400 N)

Run-Time 100 seconds 30 second 30 second 30 second Input Signal 0 - 10 VDC 0 - 10 VDC 0 - 10 VDC 0 - 10 VDC Feedback Output 0 - 10 VDC 0 - 10 VDC 0 - 10 VDC 0 - 10 VDC

Actuator

Power 24VAC±20%, 24VDC±10% 24VAC, +20%, -15% 24VAC, +20%, -15% 24VAC, +20%, -15%

16


- Pressure Sensor

LEGEND



PICCV

CGCV

HeatingWaterBoiler

F

A

C VFD

Interior ATest Room

East ATest Room

South ATest Room

West ATest Room

Test valve:- Belimo PICCV

P1

DP

HC

TT

F

A

HC

TT

F

AExisting valveCLOSED

H

CTT

F

A

HC

TT



F

A

CVFD

Interior BTest Room

East BTest Room

South BTest Room

West BTest Room

Test valve:- CGCV

P1

DP

H

CT T

F

A

H

CT T

F

AExisting valve

CLOSED

H

CT T

F

A

H

CT T



A

F

- Actuator (Analog)

- Flow Meter P

T - Differential Pressure Sensor


- Controller

VFD

DP

C Figure 3-1: Schematic of heating water Loop-A and Loop-B and instrumentation setup for Test Suite 2.

17

Table 3-2: Test set-up for room air temperature control with constant inlet pressure to control valve and variable heating water loop pump speed.

Test Designation1 Description South-A Test Room

Configuration South-B Test Room

Configuration

Test Valve Belimo PICCV-15-003 Siemens Powermite MT 599-02036 (Cv = 1.6) CL 2.1

Inlet Pressure Setpoint 29 psi (200 kPa) 25 psi (172.4 kPa)


Inlet Pressure Setpoint 29 psi (200 kPa) 25.6 psi (176.5 kPa)


Inlet Pressure Setpoint 29 psi (200 kPa) 25.3 psi (174.4 kPa) 1 CL 2.1 was conducted from January 23, 2005 at 19:30 until January 24, 2005 at 06:00.

CL 2.2 was conducted from January 25, 2005 at 19:30 until January 26, 2005 at 06:00. CL 2.3 was conducted from January 26, 2005 at 19:30 until January 27, 2005 at 06:00.

• CL 2.1 o Belimo PICCV: The inlet pressure setpoint was established to provide sufficient

differential pressure across the valve to ensure that the design flow rate could be achieved with the valve 100% open.

o Siemens Powermite MT 599-02036: The inlet pressure setpoint was adjusted to provide a flow rate with the valve 100% open that was nearly equal to the Belimo PICCV design flow rate.

• CL 2.2 and CL 2.3

o Belimo PICCV: The inlet pressure setpoint was established to provide sufficient differential pressure across the valve to ensure that the design flow rate could be achieved with the valve 100% open.

o Siemens Powermite MT 599-02038 and Powermite MT 599-02041: With the valve fully open, the inlet pressure setpoint was adjusted to produce a differential pressure across the valve that was nearly equal to the differential pressure across the fully open Siemens Powermite MT 599-02036 in CL 2.1.

Feedback control using a proportional-integral control law was used to control the speed of the heating water loop pump. To minimize pressure disturbances, the reheat coil valves for the remaining three test rooms on Loop-A (East-A, West-A and Interior-A) and the remaining three test rooms on Loop-B (East-B, West-B and Interior-B) were overridden to a closed position for the duration of the test.

18

3.2.2 Discharge Air Temperature Control with Fixed Inlet Pressure to Control Valve

The second set of tests compared the performance of the test valves for a discharge air temperature control application in which the inlet pressure to the control valve was controlled to a fixed setpoint. Two tests, designated CL 2.4 and CL 2.5, were conducted. Key differences among the tests are summarized in Table 3-3. In each of the tests, the speed of the heating water loop pump was controlled via a variable frequency drive to maintain a fixed inlet pressure to the test valve. The strategy for determining the inlet pressure setpoint for each test was as follows:



o Siemens Powermite MT 599-02036: With the valve 100% open, the inlet pressure setpoint was adjusted to produce a differential pressure across the valve that was nearly equal to the differential pressure across the 100% open Siemens Powermite MT 599-02036 in CL 2.1.



o Siemens Powermite MT 599-02036: With the valve 100% open, the inlet pressure was adjusted to provide a flow rate that was nearly equal to the Belimo PICCV design flow rate.

Feedback control using a proportional-integral control law was used to control the speed of the heating water loop pump. To minimize pressure disturbances, the reheat coil valves for the remaining three test rooms on Loop-A (East-A, West-A and Interior-A) and the remaining three test rooms on Loop-B (East-B, West-B and Interior-B) were overridden to a fixed position for the duration of the test.

Table 3-3: Test set-up for discharge air temperature control with constant inlet pressure to control valve and variable heating water loop pump speed.



Configuration

Test Valve Siemens Powermite MT 599-02036 (Cv = 1.6) Belimo PICCV-15-003

CL 2.4 Inlet Pressure Setpoint 23.7 psi (163.4 kPa) 29 psi (200 kPa)

Test Valve Belimo PICCV-15-003 Siemens Powermite MT 599-02036 (Cv = 1.6)

CL 2.5 Inlet Pressure Setpoint 29 psi (200 kPa) 24.5 psi (168.9 kPa)

1 CL 2.4 was conducted from January 28, 2005 at 10:00 until January 28, 2005 at 16:00. CL 2.5 was conducted from December 13, 2004 at 21:00 until December 14, 2004 at 03:00.

19

3.2.3 Room Temperature Control with Variable Inlet Pressure to Control Valve The third set of tests compared the performance of the test valves for a room temperature control application in which the heating water loop pump speed was constant and the inlet pressure to the control valve was allowed to vary. Two tests, designated CL 2.6 and CL 2.7, were conducted. Key differences among the tests are summarized in Table 3-4. The tests described in the previous two sections controlled the heating water loop pump speed to maintain a fixed inlet pressure at the test valves. This is not a strategy that is typically employed for pump speed control in terminal reheat applications. This strategy was utilized to create repeatable inlet pressure conditions at the test valves. Controlling to a fixed inlet pressure diminishes the impact of the pressure-independent feature of the Belimo PICCV. CL 2.6 and CL 2.7 were designed to more closely mimic operating conditions that result in a variable inlet pressure to the control valve and thereby examine the impact of the pressure independent feature of the Belimo PICCV. Consistent with the tests described in the previous two sections, the reheat coil valves for the remaining three test rooms on Loop-A (East-A, West-A and Interior-A) and the remaining three test rooms on Loop-B (East-B, West-B and Interior-B) were overridden to a fixed position for the duration of the test.

3.3 Test Conditions and Procedure In each test conducted in Test Suite 2, the test valve was controlled by a proportional-integral control algorithm running inside a Johnson Controls DX 9100 controller. The test valve modulates the flow of heating water through the coil to maintain the room temperature at the heating setpoint according to the control sequence in the controller. The control sequence commonly used to control the pressure-independent VAV terminal units at the ERS is shown graphically in Figure 3-2. A heating setpoint, cooling setpoint, maximum airflow rate and minimum airflow rate are specified. As the room temperature increases above the cooling setpoint, the airflow rate to the room increases proportionally. This is accomplished by resetting the setpoint value of the airflow rate upward and modulating the damper to achieve this flow

Table 3-4: Test set-up for room air temperature control with variable inlet pressure to control valve and constant heating water loop pump speed.



Configuration


CL 2.6 Heating Water Loop Pump Speed 63 % 63 %


CL 2.7 Heating Water Loop Pump Speed 63 % 63 %

1 CL 2.6 was conducted from January 28, 2005 at 22:00 until January 29, 2005 at 08:30. CL 2.7 was conducted from February 27, 2005 at 21:30 until February 28, 2005 at 08:00.

20

AirflowSetpoint

HeatingSet

Point

CoolingSet

Point

RoomTemperature

ValvePosition

Maximum

Minimum

FullyOpen

FullyClosed

Airflow Set Point

Valve

AirflowSetpoint

HeatingSet

Point

CoolingSet

Point

RoomTemperature

ValvePosition

Maximum

Minimum

FullyOpen

FullyClosed

Airflow Set Point

Valve

Figure 3-2: Typical control sequence at the ERS for a pressure- independent VAV box with hydronic reheat.

rate. As the room temperature decreases toward the cooling setpoint, the airflow rate set point is decreased and the damper gradually closes until it is providing the minimum flow rate. At this point the room temperature is equal to the cooling setpoint. If the zone temperature continues to decrease and reaches the heating setpoint, the reheat valve will begin to open and will attempt to raise the room temperature to the heating setpoint. In Test Suite 2, scheduled disturbances were introduced in the room airflow rate and the room (or discharge) air temperature setpoint in order to exercise the test valves over their full range of operation. The airflow rate was adjusted by setting the minimum and maximum airflow setpoints for a particular room to the same value and scheduling these parameters to change periodically. Identical airflow rate and room (or discharge) air temperature setpoint profiles were established in the South-A and South-B test rooms. The air-handling units (AHUs) serving the South-A and South-B test rooms were controlled to provide supply air at 55°F (12.8°C). The heating water supply temperature was controlled to a setpoint value of 140ºF (60°C). To minimize the influence of solar loads and increase the use of reheat, the tests involving the room temperature control were conducted overnight and concluded by 8:30 AM local time at the latest. The performance of any valve controlled with a proportional-integral control algorithm is dependent on the controller gains, the proportional band and the reset action in Johnson Controls controllers. Values of the proportional band and reset action used in Test Suite 2 are provided below: Room Temperature Control Application: CL 2.1, CL 2.2, CL 2.3, CL 2.6 and CL 2.7

• Proportional Band: -3 • Reset Action: 0.01 repeats per minute

21

Discharge Air Temperature Control Application: CL 2.4, CL 2.5 • Proportional Band: -30 • Reset Action: 0.5 repeats per minute

For a specific test (e.g., CL 2.2), the same controller gains were used for both the Belimo and Siemens valves. The controller gains used for the room temperature application are the same values typically used at the ERS. The controller gains used for the discharge air temperature control application were determined through trial and error tuning; however, discussions with personnel from Johnson Controls revealed that these values were comparable to default values commonly used for this application. The performance of a valve with a given set of controller gains is also dependent on the run-time (or stroke-time) of the valve. This refers to the time required for the valve to stroke from fully open to fully closed. The minimum run-time of the Belimo PICCV-15-003 configured with MFT settings of 20% and 70% is approximately 50 s. The run-time of the Siemens Powermite MT series globe valves is approximately 30 s.

3.4 Instrumentation The following list of measurement and control points were monitored and recorded during Test Suite 2:

1. Inlet pressure to test valve (psi) 2. Differential pressure across the test valve (psi) 3. Water flow rate (gallons per minute) 4. Commanded signal to test valve (% open) 5. Valve position feedback (% open) 6. Heating water pump speed (% of maximum or Hz) 7. Reheat coil entering water temperature (°F) 8. Reheat coil leaving water temperature (i.e., temperature at the valve, °F)

Each of these eight points was recorded at 10 second intervals using a National Instruments data acquisition system. In addition, these measurement and control points and all the remaining measurement and control points normally collected at the ERS were recorded at 1 minute intervals using the Johnson Control Metasys trending capabilities.

3.5 Results The focus of Test Suite 2 was to evaluate the control performance of the test valves. To do this, a number of performance parameters are defined: Average Temperature Error: The average temperature error, e , is given by

( ) TT n1 e

n

iispti∑

=−=

1 (1)

where

22

isptT = room or discharge air temperature setpoint at the ith data point (ºF),

iT = room or discharge air temperature at the ith data point (ºF), and n = number of data points. Average Absolute Value of Temperature Error: The average absolute value of the temperature error, e , is useful for identifying unstable control that produces oscillations in the temperature response, and is calculated from

∑=

−=n

iispt TT

n1 e

i1

. (2)

Accumulated Actuator Travel: Accumulated actuator travel, trav, is another useful measure for evaluating control performance and is calculated from

∑=

−−=n

iii vv ravt

21 (3)

where iv = feedback signal from the valve at the ith data point (% open). At each time step, the actuator travel is computed using the current feedback signal and the previous value. If the travel is less than 0.5% (i.e., 0.05 VDC for a 0 to 10 VDC feedback signal), the travel for that time increment is set to zero. Actuator Starts and Stops and Actuator Reversals: Actuator starts and stops, and actuator reversals are also used to quantify the control performance. These are integer values computed using the following algorithm:

1. At each time step, compute the direction of travel according to the following rules:

• If 1−− ii vv > 0.5%, direction = +1 • If 1−− ii vv < -0.5%, direction = -1 • Otherwise, direction = 0

2. At each time step, determine if the actuator has started or stopped according to the

following rules:

• If current direction = +1 or –1 and previous direction = 0, the actuator has started, so increment the number of starts and stops by 1

• If current direction = 0 and previous direction = +1 or -1, the actuator has stopped, so increment the number of starts and stops by 1

23

3. At each time step, determine if the actuator has reversed direction according to the

following rules:

• If current direction = +1 and the most recent nonzero value for direction was –1, the actuator has reversed direction, so increment the number of reversals by 1

• If current direction = -1 and the most recent nonzero value for direction was +1, the actuator has reversed direction, so increment the number of reversals by 1

As an example, an array of direction values given by [0 0 –1 –1 0 +1 +1 -1 0 -1 0 +1 +1 0] would have eight starts and stops and three reversals. Cumulative Change in Water Flow Rate: The cumulative change in the water flow rate, ΔQ, is calculated from

( )∑=

−−=Δ

n

iww ii

QQQ2

1 . (4)

ΔQ is effective for evaluating the control stability the terminal reheat control valves. Table 3-5 provides a summary of the results for Test Suite 2. In general, the Siemens valves maintained the temperature being controlled (either the room temperature or discharge air temperature) slightly closer to the setpoint than the Belimo valve; however, the Siemens valves also exhibited significantly greater actuator travel, number of reversals, and cumulative change in water flow rate in comparison to the Belimo valve. To better understand the results in Table 3-5, plots of representative tests are presented next. A complete set of plots for Test Suite 2 is presented in Appendix A. The first set of plots is for CL 2.2. This test compares the performance of the Belimo PICCV with an oversized Siemens valve (Cv = 2.5) for a room temperature control application with a constant inlet pressure to the control valve. Figure 3-3 shows the disturbance schedule utilized for CL 2.2 as well as CL 2.1 and CL 2.3. The first part of the test involved testing with room airflow disturbances and a fixed room setpoint temperature (71ºF, 21.7ºC), whereas the latter part of the test involved room setpoint temperature changes and a fixed room airflow rate (400 CFM, 189 L/s). Figure 3-4 shows the feedback position signal for the Belimo PICCV and the oversized Siemens globe valve. The Siemens valve actuates considerably more than the Belimo PICCV, as indicated by the greater thickness of the plotted data in Figure 3-4b in comparison to Figure 3-4a. The data in Table 3-5 shows that the actuator travel for the Siemens valve is 2.5 times that of the Belimo PICCV. As a result, the flow rate through the Siemens valve shows considerably more variability than the flow rate through the Belimo PICCV (see Figure 3-5). The data in Table 3-5 reveal that the cumulative change in the water flow rate of the Siemens valve is more than six times higher than that of the PICCV. The room temperature response in the two rooms is comparable, although the effect of the fluctuating water flow rate associated with the Siemens valve can be seen in the room temperature response in Figure 3-6b. The room airflow rate for the two test rooms, the inlet pressure to the control valves, and the entering air temperatures to the

24

Table 3-5: Summary of control performance parameters for Test Suite 2.

Average Temperature

Error 1

Average Absolute Value of Temperature

Error 1

Cumulative Change in Water

Flow Rate Test Valve

[ºF] [ºC] [ºF] [ºC]

Accumu-lated

Actuator Travel

[%]

Actuator Reversals

Actuator Starts

and Stops [GPM] [L/s]

Belimo 0.11 0.06 0.23 0.13 2178.3 937 1359 59.0 3.72 CL 2.1

Siemens 0.16 0.09 0.33 0.18 4342.9 1356 1348 176.2 11.12

Belimo 0.12 0.07 0.25 0.14 2117.8 960 1426 35.0 2.21 CL 2.2

Siemens 0.07 0.04 0.21 0.12 5328.8 1480 1393 218.0 13.76

Belimo 0.09 0.05 0.28 0.16 2143.0 1074 1389 40.3 2.54 CL 2.3

Siemens 0.04 0.02 0.24 0.13 5197.4 1601 1378 670.4 42.30

Belimo 0.11 0.06 0.37 0.21 215.4 21 183 22.1 1.39 CL 2.4

Siemens 0.14 0.08 0.51 0.28 598.2 143 467 41.7 2.63

Belimo 0.16 0.09 0.50 0.28 222.6 26 254 14.9 0.94 CL 2.5

Siemens 0.14 0.08 0.54 0.30 358.4 99 348 49.5 3.12

Belimo 0.06 0.03 0.24 0.13 1717.3 736 1132 43.9 2.77 CL 2.6

Siemens 0.02 0.01 0.22 0.12 5701.5 1659 1514 305.4 19.27

Belimo 0.06 0.03 0.23 0.13 1816.3 792 1150 42.6 2.69 CL 2.7

Siemens 0.04 0.02 0.18 0.10 5060.5 1472 1475 452.7 28.57 1 The temperature error of interest is the room temperature error for CL 2.1, CL 2.2, CL 2.3, CL 2.6 and CL 2.7,

and the discharge air temperature error for CL 2.4 and CL 2.5.

Time (h)

0 1 2 3 4 5 6 7 8 9 10 11

Roo

m A

irflo

w R

ate

Setp

oint

(CFM

)

0

100

200

300

400

500

600

700

800

900

1000

Roo

m A

irflo

w R

ate

Setp

oint

(L/s

)

0

50

100

150

200

250

300

350

400

450

Time (h)

0 1 2 3 4 5 6 7 8 9 10 11

Roo

m A

ir Te

mpe

ratu

re S

etpo

int (

F)

70

71

72

73

74

75R

oom

Air

Tem

pera

ture

Set

poni

t (C

)

21.5

22.0

22.5

23.0

23.5

Figure 3-3: Room airflow setpoint and room temperature setpoint schedules

for CL 2.1, CL 2.2 and CL 2.3.

25

reheat coils are shown in Figures 3-7 to 3-9 to demonstrate that these parameters were well controlled and did not contribute to differences in the performance of the test valves. The accumulated absolute value of the temperature error is shown in Figure 3-10. Note that this parameter is simply the result of Equation 2 multiplied by the number of data points. Most of the difference seen between the accumulated temperature error for the two rooms appears to be due to the temperature dip in the South-A test room that occurs in the first three hours of the test (see Figure 3-6a). The accumulated actuator travel, starts and stops, and reversals are shown in Figures 3-11 to 3-13. Note that the Siemens valve makes approximately 1.5 times more reversals than the Belimo PICCV, but that the number of starts and stops are nearly the same. These numbers are obviously affected by the magnitude of the threshold that is used to determine whether or not the valve is moving. The calculations in this report are all based on a threshold of 0.5% (i.e., valve position is considered stationary if the feedback signal from the valve changes by less than 0.05 VDC from one measurement to the next). Sensitivity studies were conducted to

Time (h)

0 1 2 3 4 5 6 7 8 9 10 11

Val

ve F

eedb

ack

Sig

nal (

% O

pen)

0

10

20

30

40

50

60

70

80

90

100

Time (h)

0 1 2 3 4 5 6 7 8 9 10 11

Sca

led

Val

ve F

eedb

ack

Sig

nal (

% O

pen)

0

10

20

30

40

50

60

70

80

90

100

(a) South-A: Belimo (b) South-B: Siemens

Figure 3-4: Valve position feedback signal for CL 2.2.

Time (h)

0 1 2 3 4 5 6 7 8 9 10 11

Hea

ting

Wat

er F

low

Rat

e (G

PM

)

0

1

2

3

4

5

6

Hea

ting

Wat

er F

low

Rat

e (L

/s)

0.00

0.05

0.10

0.15

0.20

0.25

0.30

0.35

Time (h)

0 1 2 3 4 5 6 7 8 9 10 11

Hea

ting

Wat

er F

low

Rat

e (L

/s)

0.00

0.05

0.10

0.15

0.20

0.25

0.30

0.35

Hea

ting

Wat

er F

low

Rat

e (G

PM)

0

1

2

3

4

5

6


Figure 3-5: Heating water flow rate for CL 2.2.

26

Time (h)

0 1 2 3 4 5 6 7 8 9 10 11

Roo

m A

ir Te

mpe

ratu

re (F

)

70

71

72

73

74

75

Roo

m A

ir Te

mpe

ratu

re (C

)

21.5

22.0

22.5

23.0

23.5

Measurement

Setpoint

Time (h)

0 1 2 3 4 5 6 7 8 9 10 11

Roo

m A

ir Te

mpe

ratu

re (F

)

70

71

72

73

74

75

Roo

m A

ir Te

mpe

ratu

re (C

)

21.5

22.0

22.5

23.0

23.5

Measurement

Setpoint


Figure 3-6: Room temperature control for CL 2.2.

Time (h)

0 1 2 3 4 5 6 7 8 9 10 11

Roo

m A

irflo

w R

ate

(CFM

)

0

200

400

600

800

1000R

oom

Airf

low

Rat

e (L

/s)

0

100

200

300

400

Setpoint

Measurement

Time (h)

0 1 2 3 4 5 6 7 8 9 10 11

Roo

m A

irflo

w R

ate

(CFM

)

0

200

400

600

800

1000

Roo

m A

irflo

w R

ate

(L/s

)

0

100

200

300

400

Setpoint

Measurement


Figure 3-7: Room airflow control for CL 2.2.

Time (h)

0 1 2 3 4 5 6 7 8 9 10 11

Inle

t Pre

ssur

e to

Val

ve (p

si)

20

22

24

26

28

30

32

Inle

t Pre

ssur

e to

Val

ve (k

Pa)

140

150

160

170

180

190

200

210

220

PICCV

Globe Valve

Figure 3-8: Inlet pressure to

control valves for CL 2.2.

Time (h)

0 1 2 3 4 5 6 7 8 9 10 11

Inle

t Air

Tem

pera

ture

to R

ehea

t Coi

l (C

)

13.0

13.5

14.0

Inle

t Air

Tem

pera

ture

to R

ehea

t Coi

l (F)

55.0

55.5

56.0

56.5

57.0

57.5

58.0

Coil with PICCV

Coil withGlobe Valve

Figure 3-9: Entering air temperature

to reheat coil for CL 2.2.

27

Time (h)

0 1 2 3 4 5 6 7 8 9 10 11

Acc

umul

ated

Abs

olut

e V

alue

of R

oom

Tem

pera

ture

Err

or (F

-min

)

0

50

100

150

200

250

Acc

umul

ated

Abs

olut

e V

alue

of R

oom

Tem

pera

ture

Err

or (C

-min

)

0

20

40

60

80

100

120

Globe Valve

PICCV

Figure 3-10: Accumulated room

temperature error for CL 2.2.

Time (h)

0 1 2 3 4 5 6 7 8 9 10 11

Acc

umul

ated

Act

uato

r Tra

vel

0

500

1000

1500

2000

2500

3000

3500

4000

4500

5000

5500

6000

PICCV

Globe Valve

Figure 3-11: Accumulated actuator

travel for CL 2.2.

Time (h)

0 1 2 3 4 5 6 7 8 9 10 11

Star

ts a

nd S

tops

0

200

400

600

800

1000

1200

1400

1600

1800

2000

PICCV

Globe Valve

Figure 3-12: Accumulated starts

and stops for CL 2.2.

Time (h)

0 1 2 3 4 5 6 7 8 9 10 11

Rev

ersa

ls

0

200

400

600

800

1000

1200

1400

1600

1800

2000

PICCV

Globe Valve

Figure 3-13: Accumulated reversals

for CL 2.2.

see how the results are affected by a threshold change and indicated that although the magnitudes of the performance parameters (e.g., starts and stops, reversals) change, the changes are relatively small in comparison to the differences observed between the parameters for the two valves. The next set of plots to consider is for the test CL 2.4. In this test the performance of the Belimo PICCV is compared to a correctly sized Siemens globe valve for a discharge air temperature control application with a constant inlet pressure to the control valve. This test was chosen because the inlet pressure for the Belimo PICCV is relatively unstable in comparison to the inlet pressure for the Siemens valve. This can be seen in Figure 3-14 and results from unstable control of the Loop-B heating water pump that serves this valve. A more stable inlet pressure should make stable flow control more achievable. Thus, the conditions for this test favor the Siemens valve.

28

Time (h)

0 1 2 3 4 5 6 7In

let P

ress

ure

to V

alve

(psi

)

20

22

24

26

28

30

32

Inle

t Pre

ssur

e to

Val

ve (k

Pa)

140

150

160

170

180

190

200

210

220

PICCV

Globe Valve

Figure 3-14: Inlet pressure to control valves for CL 2.4.

In CL 2.4, the airflow rate to the test rooms was a constant value of 400 CFM (189 L/s). The discharge air temperature setpoint was adjusted hourly in 5ºF (2.8ºC) increments from 60ºF (15.6ºC) to 85ºF (29.4ºC). The feedback position of the valves is shown in Figure 3-15. The most interesting thing to note about the feedback position is the fact that the Siemens valve feedback indicates it is closed for the first 75 minutes of the test. During the next hour, the Siemens valve fluctuates between 0 and 5% open. As the test continues, the position fluctuations decrease as the valve opens further. By contrast, the Belimo PICCV position feedback signal does not fluctuate, indicating it provides more stable control despite the less stable inlet pressure conditions that it experiences. The heating water flow rates for the valves are shown in Figure 3-16. Although the position feedback for the Siemens valve indicated it was closed for the first 75 minutes of the test, the water flow rate was nonzero during this period. Comparing the two plots, it is clear that the flow rate through the Belimo PICCV is more stable than that through the Siemens valve. The data in Table 3-5 support this. Note that the cumulative change in the water flow rate for the Siemens valve is approximately twice the value for the PICCV (41.7 GPM [2.63 L/s] versus 22.1 GPM [1.39 L/s]). In addition, the PICCV is able to provide stable flow even when the water flow rate

Time (h)

0 1 2 3 4 5 6 7

Val

ve F

eedb

ack

Sig

nal (

% O

pen)

0

10

20

30

40

50

60

70

80

90

100

Time (h)

0 1 2 3 4 5 6 7

Scal

ed V

alve

Fee

dbac

k S

igna

l (%

Ope

n)

0

10

20

30

40

50

60

70

80

90

100

(a) South-B: Belimo (b) South-A: Siemens

Figure 3-15: Valve position feedback signal for CL 2.4.

29

Time (h)

0 1 2 3 4 5 6 7

Hea

ting

Wat

er F

low

Rat

e (L

/s)

0.00

0.05

0.10

0.15

0.20

0.25

0.30

0.35

Hea

ting

Wat

er F

low

Rat

e (G

PM

)

0

1

2

3

4

5

6

Time (h)

0 1 2 3 4 5 6 7

Hea

ting

Wat

er F

low

Rat

e (G

PM

)

0

1

2

3

4

5

6

Hea

ting

Wat

er F

low

Rat

e (L

/s)

0.00

0.05

0.10

0.15

0.20

0.25

0.30

0.35


Figure 3-16: Heating water flow rate for CL 2.4.

is less than 0.2 GPM (0.013 L/s). The importance of having stable flow at such low flow rates will become more evident when the results in Section 4.5 are considered, but suffice it to say that that the low load conditions that lead to such low flow rates are common in terminal reheat applications. For the current tests, the ability to deliver stable control at low water flow rates results in stable temperature control when the discharge air temperature setpoint is 60 and 65ºF (15.6 and 18.3ºC). This can be seen in Figure 3-17a. By contrast, the Siemens valve produces a temperature response that fluctuates considerably at these low air temperature setpoints. Although discharge air temperature control is not the typical application for reheat coil valves, it is common for the valves to operate at low heating water flow rates. If the valve is unable to deliver low flow rates, the room temperature response will tend to mimic the response seen in the first two hours of Figure 3-17b. The accumulated discharge air temperature error for CL 2.4 is shown in Figure 3-18. The difference in the accumulated error between the Belimo and Siemens valves can be attributed primarily to oscillations in temperature associated with the Siemens valve control at setpoint values of 60 and 65ºF (15.6 and 18.3ºC) (see Figure 3-17b). Accumulated actuator travel, starts and stops, and reversals are plotted in Figures 3-19 to 3-21. Although water flow and discharge air temperature measurements indicate the Siemens valve is opening and closing while the discharge air temperature is controlled to 60ºF (15.6ºC), the feedback signal from the Siemens valve indicates it is closed during this time. As a result, the accumulated actuator travel, starts and stops, and reversals remain equal to zero for the Siemens valve until the setpoint is increased to 65ºF (18.3ºC). If the feedback signal for the Siemens valve reflected the actual operation of the valve at low flow rates, the disparity in actuator travel, starts and stops, and reversals would be even more pronounced than it currently is. Even so, the Siemens valve travel is approximately 2.8 times greater than that of the Belimo valve, the starts and stops is approximately 2.5 times greater, and the reversals is approximately seven times greater.

30

Time (h)

0 1 2 3 4 5 6 7

Dis

char

ge A

ir Te

mpe

ratu

re (F

)

55

60

65

70

75

80

85

90

Dis

char

ge A

ir Te

mpe

ratu

re (C

)

14

16

18

20

22

24

26

28

30

32

Measurement

Setpoint

Time (h)

0 1 2 3 4 5 6 7

Dis

char

ge A

ir Te

mpe

ratu

re (F

)

55

60

65

70

75

80

85

90

Dis

char

ge A

ir Te

mpe

ratu

re (C

)

14

16

18

20

22

24

26

28

30

32

Measurement

Setpoint


Figure 3-17: Discharge air temperature control for CL 2.4.

Time (h)

0 1 2 3 4 5 6 7

Accu

mul

ated

Abs

olut

e Va

lue

of D

isch

arge

Tem

pera

ture

Erro

r (F-

min

)

0

50

100

150

200

250Ac

cum

ulat

ed A

bsol

ute

Valu

eof

Dis

char

ge T

empe

ratu

re E

rror

(C-m

in)

0

20

40

60

80

100

120

Globe Valve

PICCV

Figure 3-18: Accumulated discharge

air temperature error for CL 2.4.

Time (h)

0 1 2 3 4 5 6 7

Acc

umul

ated

Act

uato

r Tra

vel

0

100

200

300

400

500

600

PICCV

Globe Valve


travel for CL 2.4.

Time (h)

0 1 2 3 4 5 6 7

Sta

rts a

nd S

tops

0

100

200

300

400

500

PICCV

Globe Valve

Figure 3-20: Accumulated starts


Time (h)

0 1 2 3 4 5 6 7

Rev

ersa

ls

0

50

100

150

200

PICCV

Globe Valve


for CL 2.4.

31

CL 2.6 and CL 2.7 examined the control performance of the Belimo PICCV and two Siemens valves of different sizes (different Cv values) for a room temperature control application with variable inlet pressure to the control valve. Previous tests with fixed inlet pressures negated the pressure-independent aspect of the Belimo PICCV. The results in Table 3-5 indicate that there is little difference in the temperature control between the Belimo and Siemens valves; however, the Belimo PICCV accomplishes the temperature control with approximately three times less actuator travel, approximately 20% fewer starts and stops, and approximately half as many reversals. Furthermore, the cumulative change in the water flow rate of the Belimo PICCV was seven to eleven times less than that for the Siemens valve. The plotted results for CL 2.6 and CL 2.7 are very similar to those for CL 2.2. For this reason, the plotted results for the two tests are presented only in the Appendix A. One of the objectives of Test Suite 2 was to examine the impact of valve sizing on control performance. Three Siemens valves, each having a different flow coefficient, were compared with the Belimo PICCV in CL 2.1 (Cv = 1.6 for the correctly sized Siemens valve), CL 2.2 (Cv = 2.5), and CL 2.3 (Cv = 4.0). Control performance is expected to deteriorate as the valve size increases (as Cv increases) because the valve authority decreases. Considering only the temperature errors in Table 3-5, differences in control performance are difficult to distinguish between the three tests. It could even be concluded based on the average temperature errors in Table 3-5 that the temperature control improves as the valve size increases. This should not be interpreted as a general result. The explanation of this result stems from the fact that most of the temperature error is accumulated immediately after a step change in the disturbance variable (either the airflow rate or the room temperature setpoint). The oversized valves are able to deliver higher flow rates than the correctly sized valve, thereby reducing the temperature error more quickly and producing lower average temperature errors. The cumulative change in the water flow rate is a more effective parameter for drawing out the control performance differences for these tests. Note that the ratio of the cumulative change in water flow rate for the Siemens valve to the Belimo valve increases from 3.0 for CL 2.1, to 6.2 for CL 2.2, to 16.6 for CL 2.3. There are two caveats to consider when analyzing the results of these tests: • The inlet pressure to the Siemens valve for CL 2.3 is less stable than that for the Belimo

valve (see Figure A-28). Although the performance parameters will be skewed to favor the Belimo valve for this test, the difference in the inlet pressure does not account for the extreme differences in actuator travel, actuator reversals, and the cumulative change in the water flow rate.

• As noted in Section 2.5, the “correctly sized” Siemens valve is oversized by approximately

21% based on sizing that is intended to produce a 4 psi pressure drop at the design flow of 3 GPM (0.19 L/s), and by approximately 60% based on ASHRAE criteria. Differences in the control performance of the three Siemens valves are likely to be more difficult to identify since all the valves are in fact oversized.

A comment about controller gains is appropriate before concluding the discussion of Test Suite 2. Recall that for a specific test (e.g., CL 2.2), the same controller gains were used for both the Belimo and Siemens valves. The controller gains used for the room temperature application are the same values typically used for this application at the ERS. The controller gains used for

32

the discharge air temperature control application were determined through trial and error tuning and are comparable to default values recommended by Johnson Controls for this type of application. Nonetheless, the stroke time of the valves is not the same (recall the stroke time is approximately 50 s for the PICCV and approximately 30 s for the globe valve). The shorter stroke time of the Siemens valve means that it will respond more quickly than the Belimo valve, making the Siemens valve more prone to stability problems whereas the Belimo valve is more prone to having a sluggish response. Tuning specific to the valve and application is ultimately necessary to obtain the best performance from either valve.

3.6 Conclusions Closed-loop tests were conducted to quantify the control performance of the Belimo PICCV-15-003 and three Siemens Powermite MT valves having different Cv values. The three Siemens valves included a correctly sized valve (Powermite MT 599-02036 with Cv = 1.6), an oversized valve (Powermite MT 599-02038 with Cv = 2.5), and a very oversized valve (Powermite MT 599-02041 with Cv = 4.0). Test Suite 2 was performed to exercise the valves and analyze how they performed over a broad range of conditions. Test Suite 2 consisted of the following: 1) room temperature control application with fixed inlet pressure to control valve and variable heating water loop pump speed; 2) discharge air temperature control application with fixed inlet pressure to control valve and variable heating water loop pump speed; and 3) room temperature control application with variable inlet pressure to control valve and constant heating water loop pump speed. Control performance was evaluated in terms of the temperature control, actuator travel, actuator starts and stops, actuator reversals, and the cumulative change in the water flow rate. Actuator travel, actuator reversals, and the cumulative change in the water flow rate were consistently and significantly less for the Belimo valve in comparison to the Siemens valves. The Belimo valve also tended to have fewer starts and stops, although there were three cases (CL 2.1, CL 2.2, and CL 2.3) where the Belimo valve had a slightly higher number of starts and stops. These results confirm what can be visually observed from plots of the valve feedback signals, flow rates through the valves, and temperature responses associated with the valves. Specifically, the Belimo valve control was more stable than the Siemens valve control for the tests conducted and the tuning parameters utilized. The temperature control of the Belimo and Siemens valves was similar, with the exception occurring for operation at low flow rates. The Belimo valve provided stable control under all test conditions (even CL 2.4 when the inlet pressure to the Belimo valve was much more oscillatory than the inlet pressure to the Siemens valve) and was capable of producing stable flow rates below 0.2 GPM (0.013 L/s). By contrast, the Siemens valve had difficulty providing stable flow at low flow rates and instead would tend to open and close periodically with resultant flow rates that fluctuated between 0 and 0.25 GPM (0.016 L/s). As a result, the temperature being controlled tended to fluctuate as well. The impact of valve sizing on control performance was made especially apparent by considering the cumulative change in the water flow rate. This parameter, which represents the sum of the change in the water flow rate from the current sampling time to the previous sampling time, increased significantly as the flow coefficient of the Siemens valve increased and the valve authority decreased.

33

4 Terminal Reheat Closed Loop Test – System Performance Test

The purpose of this suite of tests, which is designated Test Suite 3, was to compare the system performance characteristics of Belimo PICCVs to correctly sized Siemens Powermite MT globe valves for a VAV terminal reheat application. The test consisted of evaluating energy consumption and control characteristics as AHU-A and AHU-B and associated test rooms were operated normally.

4.1 Test Units Testing compared the performance of four Belimo PICCVs and four correctly sized Siemens Powermite MT series globe valve and actuator assemblies, as outlined in Table 4-1.

4.2 Test Set-Up Figure 4-1 is a schematic of the test set-up for the closed loop system performance testing. Three identical Belimo PICCVs were installed in the perimeter test rooms on Test System A. The fourth Belimo PICCV was installed in the interior test room on Test System A. Likewise, three identical Siemens Powermite MT valves were installed in the perimeter test rooms on Test System B and a fourth Siemens Powermite MT valve was installed in the interior test room on Test System B. The valves were sized to meet design loads in the test rooms. The heating coils in the perimeter test rooms are single-row plate fin type coils with a design water flow rate of 3 GPM (0.19 L/s) and a design water pressure drop of 1.4 ft. of water (4.19 kPa). The heating coils in the interior test rooms are single-row plate fin type coils with a design water flow rate of 1.2 GPM (0.076 L/s) and a design water pressure drop of 2.34 ft. of water (7.0 kPa). An Endress Hauser model Cerabar M PMC 41 single-point pressure transducer and a model Deltabar S PMD 235 differential pressure transducer were used to measure the inlet pressure and pressure drop, respectively, of the South-A and South-B valves. Specifications for these instruments are provided in Section 2.2. Dwyer Series 619 single-point pressure transmitters (0 – 50 psig [0 – 344.8 kPa] range; accuracy of ±0.5 % of full scale) and Series 629 differential pressure transmitters (0 – 25 psig [0 – 172.4 kPa] range; accuracy of ±0.5 % of full scale) were used to measure the inlet pressure and pressure drop, respectively, of the valves in the remaining test rooms. The speeds of the Loop-A and Loop-B heating water pumps were controlled via separate variable frequency drives to maintain a fixed differential pressure between the heating water supply and return line for each loop. The differential pressure was measured with a Dwyer Series 629 differential pressure transmitter installed between the South and East test rooms on each loop. Test Suite 3 consisted of three tests. For two of the tests, designated CL 3.1 and CL 3.2, the differential pressure setpoint was determined such that the design flow of each loop could be achieved and resulted in different setpoints being used for Loop-A and Loop-B depending on which set of valves was installed on a particular loop. For the third test (designated CL 3.3), the differential pressure setpoint utilized was the same for the two loops. The procedure employed to determine the appropriate differential pressure setpoint in each loop is outlined as follows:

34

Table 4-1: Valve specifications for Test Suite 3.

Perimeter Test Rooms Interior Test Rooms Designation

Belimo PICCV Siemens Powermite MT Belimo PICCV Siemens Powermite

MT Manufacturer Belimo Siemens Belimo Siemens

Model PICCV-15-003 Powermite MT 599-02036 PICCV-15-001+


Type PICCV Globe (Stroke 7/32") PICCV


Line Size 1/2 " 1/2 " 1/2 " 1/2 " Cv N/A 1.6 N/A 0.63 Design Flow Rate 3 GPM (0.19 L/s) N/A 1.5 GPM (0.095 L/s) N/A

Valve

Close-Off Pressure 200 PSI (1379 kPa) 160 PSI (1103 kPa) 200 PSI (1379 kPa) 160 PSI (1103 kPa) Manufacturer Belimo Siemens Belimo Siemens

Model LR24-MFT US+NO+P-10028 SQS65U 264-02036

LR24-MFT US+NO+P-10028 SQS65U 264-02032


Fail-in-Place, DA/RA (adjustable) Fail-in-Place, RA

Force 35 in-lbf (4 N-m) min. torque 90 lbf (400 N)

35 in-lbf (4 N-m) min. torque 90 lbf (400 N)

Run-Time 100 seconds 30 second 100 seconds 30 second Input Signal 0 - 10 VDC 0 - 10 VDC 0 - 10 VDC 0 - 10 VDC Feedback Output 0 - 10 VDC 0 - 10 VDC 0 - 10 VDC 0 - 10 VDC

Actuator

Power 24VAC±20%, 24VDC±10% 24VAC, +20%, -15%

24VAC±20%, 24VDC±10% 24VAC, +20%, -15%

35

LEGEND



PICCV

CGCV

HeatingWaterBoiler

F

A

C VFD

Interior ATest Room

East ATest Room

South ATest Room

West ATest Room


HC

TT

F

A

HC

TT

F

A

HC

TT

F

A

HC

TT

F

A

CVFD

Interior BTest Room

East BTest Room

South BTest Room

West BTest Room

Test valve:- CGCV

HC

T T

F

A

H

CT T

F

A

H

CT T

F

A

H

CT T

A

F

- Actuator (Analog)

- Flow Meter


- Pressure SensorP

T - Differential Pressure Sensor


- Controller

VFD

DP

C




P1

DP

P1

DP

P1 DP

P1

DP

DP

Test valve:- CGCV

Test valve:- CGCV

Test valve:- CGCV

DP

P1

DP

P1DP

P1

DP

P1

DP

Figure 4-1: Schematic of heating water Loop-A and Loop-B and instrumentation setup for Test Suite 3.

36

1. Open all balancing valves on Loop-A to 100% open. 2. Open all control valves on Loop-A to 100% open and set heating water pump speed for

Loop-A to 100%. Check to ensure that the design flow rate of 10.2 GPM (0.64 L/s) is being achieved and that each test room is achieving design flow (3 GPM [0.19 L/s for perimeter rooms, 1.2 GPM [0.076 L/s] for interior room).

3. Decrease Loop-A heating water pump speed until loop flow rate begins to decrease below design.

4. Increase Loop-A heating water pump speed until loop flow rate is achieved and check that all test rooms achieve design flow. The corresponding Loop-A differential pressure represents the minimum pressure difference that will achieve the design flow.

5. Multiply the minimum pressure difference from step 4 by 1.1 to determine the Loop-A differential pressure setpoint.

6. Repeat steps 1 through 5 for Loop-B. The proportional band and reset action currently used at the ERS for the terminal reheat coil control valves (proportional band = -3, reset action = 0.01 repeats per minute) were used for both the Belimo and Siemens valves. The A and B test systems at the ERS were set up identically. The systems operated in an occupied mode from 6:00 am until 6:00 pm. and operated in a night setback mode otherwise. During the occupied period, the room cooling and heating setpoints were set to 72°F (22.2°C) and 70°F (21.1°C), respectively. Baseboard heating and lighting loads were scheduled to provide variable internal thermal gains. AHU-A and AHU-B supply air temperature and static pressure setpoints were constant values of 55°F (12.8°C) and 1.2 in of water (2.99 kPa), respectively. The night setback cooling and heating setpoints were set to 60°F (15.6°C) and 85°F (29.4°C), respectively.

4.3 Test Conditions and Procedure The three tests conducted as part of Test Suite 3 are summarized in Table 4-2. CL 3.1 and CL 3.2 are essentially identical in the manner in which they were set-up. The only difference in the tests was that in CL 3.1, the Belimo valves were installed in the test rooms for System A, whereas for CL 3.2 they were installed in the test rooms for System B. The procedure described in Section 4.2 was used to determine the differential pressure setpoint that was used to control the Loop-A and Loop-B heating water pumps. Differences in the test valves resulted in significantly different setpoint values in the two systems. CL 3.3 was identical to CL 3.2 except that the differential pressure setpoint was the same for the two systems. The setpoint value selected (7.7 psi or 53.09 kPa) was higher than necessary for the Siemens valves with all the balancing valves open and, therefore, produced higher than the design flow rate for the system. The setpoint for CL 3.3 was somewhat lower than the value used for the Belimo valves in CL 3.1 and CL 3.2, but was determined to be large enough to achieve the design flow rate of the system in which the Belimo valves were installed. For all the tests, the ERS test systems were operated according to the test setup and schedules described in Section 4.2.

37

Table 4-2: Test set-up for Test Suite 3.

Test Designation1 Description System A Test Room

Configuration System B Test Room

Configuration

Test Valves

Perimeter Rooms: Belimo PICCV-15-003 Interior Room: Belimo PICCV-15-001+

Perimeter Rooms: Siemens Powermite MT 599-02036 Interior Room: Siemens Powermite MT 599-02032 CL 3.1

Differential Pressure Setpoint 9.1 psi (62.74 kPa) 5.2 psi (35.85 kPa)

Test Valves

Perimeter Rooms: Siemens Powermite MT 599-02036 Interior Room: Siemens PowermiteMT 599-02032

Perimeter Rooms: Belimo PICCV-15-003 Interior Room: Belimo PICCV-15-001+ CL 3.2


Test Valves

Perimeter Rooms: Siemens Powermite MT 599-02036 Interior Room: Siemens Powermite MT 599-02032

Perimeter Rooms: Belimo PICCV-15-003 Interior Room: Belimo PICCV-15-001+ CL 3.3


1 CL 3.1 was conducted over 9 days from January 12, 2005 until January 20, 2005. CL 3.2 was conducted over 6 days from January 30, 2005 until February 4, 2005. CL 3.3 was conducted over 4 days from February 5, 2005 until February 8, 2005.

4.4 Instrumentation The measurement and control points normally collected at the ERS were recorded at 1-minute intervals. In addition, the inlet pressure to each control valve, the differential pressure across each control valve, and the system differential pressure for Loop-A and Loop-B were monitored and trended at 1-minute intervals.

4.5 Results The results of Test Suite 3 are quantified in terms of energy use and control performance. The energy use characterization is restricted to the heating water loop pump and the energy transferred in the reheat coils in the test rooms since these quantities are directly impacted by the reheat coil valves. The control performance is characterized by the cumulative temperature error in the test rooms and the cumulative change in the water flow rate to the test rooms. Each of these parameters is described in further detail below. Heating Water Loop Pump Energy: The power used by the circulating pumps on Loop-A and Loop-B is measured at 1-minute intervals using a watt transducer. The 1-minute power measurements are converted to BTU/min and summed over the occupied period to determine the total energy use in BTUs.

38

Water-side Energy Transfer Rate: The energy transferred from the heating water in the terminal reheat coils, wq& , is given in units of BTU/min by ( ) 60 500 / TTQq ewlwww −=& (5) where

wQ = heating water flow rate (GPM), lwT = leaving water temperature (ºF), and ewT = entering water temperature (ºF).

The water-side energy transfer rate will be a negative quantity since heat is transferred from the water. Air-side Energy Transfer Rate: The energy transferred to the air passing over the terminal reheat coils, aq& , is given in units of BTU/min by ( ) 60 / .081 eadaaa TTQq −=& (6) where

aQ = airflow rate to the test room (CFM), daT = discharge air temperature (ºF), and eaT = entering air temperature (ºF).

The air-side energy transfer rate will be a positive quantity since heat is transferred to the air. Cumulative Temperature Error: The cumulative temperature error, E, is calculated from

( )∑=

−=n

iihspt TTE

i1

0,max (7)

where

ihsptT = room heating setpoint at the ith data point (ºF),

iT = room air temperature at the ith data point (ºF), and n = number of data points. If the room temperature is above the heating setpoint, the error for that measurement is set equal to zero. The assumption is that if the temperature is above the heating setpoint, the terminal reheat valve is closed and therefore does not have any influence over the room temperature.

39

Thus, the calculation in Equation 7 is an attempt to limit the cumulative temperature error to include only that part of the operation over which the terminal reheat valve has control. Cumulative Change in Water Flow Rate: The cumulative change in the water flow rate is calculated from Equation 4 given in Section 3.5. Results from Test Suite 3 are summarized in Tables 4-3 and 4-4. Table 4-3 provides the daily occupied period averages for CL 3.1, CL 3.2, and CL 3.3 for the heating water loop pump energy, the energy transferred from the water in all the terminal reheat coils for a particular system (i.e., the sum of the energy transferred in East-A, South-A, West-A, and Interior-A), the energy transferred to the air in the terminal reheat coils for all rooms of a particular system, and the cumulative temperature error of all the test rooms of a particular system. Table 4-3 also includes a column providing the energy balance error between the water-side and the air-side of the terminal reheat coil. The energy balance error is computed from

( )aw

aweb qq

qqe

5.0

+

−= (8)

where wq = water-side energy transfer (BTU), and aq = air-side energy transfer (BTU). The water-side and air-side energy transfer values in columns 4 and 5 of Table 4-3 were used to compute the energy balance error. Table 4-4 provides the daily occupied period averages for CL 3.1, CL 3.2, and CL 3.3 for the cumulative change in the water flow rate in each of the eight terminal reheat coils. Rooms that have Belimo PICCVs are shaded gray in Table 4-4. The results in Table 4-3 indicate that for CL 3.1 and CL 3.2, the system controlled by the Belimo PICCVs used more energy to operate the heating water loop pump, slightly less heating energy in the terminal reheat coils, had a higher cumulative temperature error, and had more stable control of the water flow rate and room air temperature. Discussion of these results follows:

• The higher loop pump energy use stems from the higher system differential pressure that the Belimo loop pump had to maintain in CL 3.1 and CL 3.2 (see conditions in Table 4-2). The procedure utilized to establish the system differential pressure setpoints was considered to be representative of how a test and balance contractor would determine appropriate system setpoint values. The higher setpoints associated with the system served by the Belimo valves resulted in loop pumping energy that was 50 to 60% higher than that of the other system. The heating water loop flow rate and pumping power are shown in Figure 4-2 for January 18, 2005. Recall that the system design flow rate is

40

Table 4-3: Daily average energy use and temperature control characterization for the occupied period of Test Suite 3.

Heating Water Loop Pump Energy Water-Side Energy1 Air-Side Energy1 Cumulative

Temperature Error1 Test System / Valve

[BTU] [kJ] [BTU] [kJ] [BTU] [kJ]

Energy Balance Error [%] [°F] [°C]

A / Belimo 10560 11141 -137,435 -144,994 141,788 149,586 -3.12 767.3 426.8 CL 3.1

B / Siemens 6507 6865 -147,344 -155,448 147,242 155,340 0.07 610.0 338.9

B / Belimo 9054 9552 -108,573 -114,545 113,353 119,587 -4.31 345.4 191.9 CL 3.2

A / Siemens 6096 6431 -109,482 -115,504 116,754 123,175 -6.43 261.7 145.4

B / Belimo 8358 8818 -109,581 -115,608 114,818 121,133 -4.67 430.6 239.2 CL 3.3

A / Siemens 8137 8585 -109,590 -115,617 118,782 125,315 -8.05 304.5 169.2 1 The water-side energy, air-side energy, and cumulative temperature error are computed by summing the appropriate minute by minute values during

the occupied period for each test room on a given system.

Table 4-4: Daily average heating water flow control characterization for Test Suite 3.

Cumulative Change in Water Flow Rate [GPM] Cumulative Change in Water Flow Rate [L/s] Test

EA EB IA IB SA SB WA WB EA EB IA IB SA SB WA WB

CL 3.1 12.66 58.60 5.74 6.33 14.29 34.03 19.47 47.35 0.80 3.70 0.36 0.40 0.90 2.15 1.23 2.99

CL 3.2 35.95 15.72 8.15 6.54 36.80 13.41 48.76 17.66 2.27 0.99 0.51 0.41 2.32 0.85 3.08 1.11

CL 3.3 50.33 17.06 9.20 6.36 51.83 14.76 65.00 18.49 3.18 1.08 0.58 0.40 3.27 0.93 4.10 1.17

41

Time (h)

0 4 8 12 16 20 24

Hea

ting

Wat

er L

oop

Flow

Rat

e (G

PM)

0

1

2

3

4

5

6

7

8

9

10

Hea

ting

Wat

er L

oop

Flow

Rat

e (L

/s)

0.0

0.1

0.2

0.3

0.4

0.5

0.6Globe Valve

PICCV

Time (h)

0 4 8 12 16 20 24

Hea

ting

Wat

er L

oop

Pum

ping

Pow

er (W

)

100

200

300

400

500

600

Globe Valve

PICCV

(a) Heating water loop flow rate. (b) Heating water loop pumping power.

Figure 4-2: Pumping performance for January 18, 2005 (CL 3.1).

10.2 GPM (0.644 L/s), so Figure 4-2 is representative of a low-load condition. These results are typical of the pumping performance observed for CL 3.1 and CL 3.2.

• The differences in the terminal reheat energy use between the two systems are small, and

measurement uncertainty associated with the air and water flow rates and temperatures are significant, particularly at water flow rates below 0.5 GPM (0.032 L/s). Note that the energy balance error between the air and water-sides of the terminal reheat coils can exceed 6% in CL 3.1 and CL 3.2. Thus, it cannot be concluded from these tests that the Belimo PICCV results in lower energy use in the terminal reheat coils in comparison to the Siemens Powermite MT series globe valves.

• The higher cumulative temperature errors for the test rooms controlled with Belimo

valves is somewhat misleading. If the cumulative error is averaged over four test rooms and 12 hours of operation (i.e., 12 hours X 60 minutes per hour X 4 test rooms = 2880 minutes), the differences in Table 4-3 become insignificant. For instance, the average errors for CL 3.1 are 0.27°F (0.15°C) for the Belimo rooms and 0.21°F (0.12°C) for the Siemens rooms. The differences are even less significant in the other tests in Test Suite 3. The higher cumulative temperature errors do, however, point out an apparent difference in the performance of the Belimo and Siemens valves. Closer inspection of the test data indicates that the Belimo valves demonstrate less aggressive control. This was seen in the results in Chapter 3 and could be due to the difference in the stroke times of the valves, or perhaps to the manner in which the two valves respond to their input signal.

Figure 4-3 shows the room temperature response in the eight test rooms for the occupied period on January 18, 2005. The responses for the Belimo and Siemens rooms are comparable – all rooms are maintained near the heating setpoint of 70°F (21.1°C), except when the heating loads in the rooms decrease and the terminal unit control switches over to the cooling mode. The main difference in the responses is that the temperature of the rooms controlled by the Siemens valves fluctuates more around the heating setpoint. In addition, although it is difficult to distinguish in Figure 4-3, the Siemens valves seemed

42

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Figure 4-3: Room temperature control for January 18, 2005 (CL 3.1)

to respond somewhat more aggressively to disturbances. This is more apparent in Figure 4-4, where the heating water flow rate to each room is plotted for the occupied period. At hour 10 (4:00 PM) in Figure 4-4, the baseboard heating in all the test rooms is turned off. This represents a considerable load, and the terminal reheat coil valves respond by increasing the water flow rate through the coils. Note the spike at hour 10 in Figure 4-4b. The Siemens valves respond aggressively to the disturbance and, although not distinguishable in Figure 4-3, maintain the temperatures in the System B test rooms closer to the heating setpoint than the Belimo valves do in the System A test rooms.

• The more stable control exhibited by the Belimo valves is evident from Figure 4-4, in which it can be seen that the heating water flow rate through the Siemens valves fluctuates considerably more than the flow rate through the Belimo valves. The difference is particularly noticeable at flow rates less than 0.3 GPM (0.019 L/s). This is significant because 35 to 45% of the time that the Belimo valves in the perimeter rooms were modulating during CL 3.1, CL 3.2 and CL 3.3, the heating water flow rate through an individual valve was between 0.1 and 0.3 GPM (0.006 and 0.019 L/s). Figure 4-5 shows the cumulative change in flow rate for the occupied period on January 18, 2005. The more unstable the flow rate, the larger this parameter will be. With the exception of the interior rooms, the cumulative change in flow rate for the Siemens rooms is two to five times greater than that for the Belimo rooms. This particular day of operation is representative of the average results summarized in Table 4-4.

The results for CL 3.3 are essentially the same as those for CL 3.1 and CL 3.2, with the exception that the loop pump energy use is now the same for the two systems. The heating water loop flow rate and pumping power are shown in Figure 4-6 for February 6, 2005, a day that is representative of a low-load condition. These results are typical of the pumping performance observed for CL 3.3. Recall that in CL 3.3 the same system differential pressure setpoint was used to control the loop pumps in the two systems. This system differential pressure setpoint was higher than necessary for the Siemens valves and somewhat lower than the value used for the system controlled by Belimo valves in CL 3.1 and CL 3.2. There were no adverse affects observed from the change in the system differential pressure setpoint.

43

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Figure 4-4: Heating water flow rate for January 18, 2005 (CL 3.1)

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Figure 4-5: Cumulative change in heating water flow rate for January 18, 2005 (CL 3.1)

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Figure 4-6: Pumping performance for February 6, 2005 (CL 3.3).

44

Morning startup is often problematic in systems using conventional control valves because, if not properly balanced, the branches with the smaller pressure drops will have water flow rates in excess of the design values for these branches, whereas the branches with the higher pressure drops will have flow rates that are less than the design values. The problem is more pronounced in systems having a direct return piping arrangement for the terminal reheat coils. This phenomenon, in which the branches with the lowest pressure drop “steal” water from other branches, is difficult to replicate at the test facility because the ERS has a reverse return piping arrangement, the systems are well balanced, and the ERS has only four zones on each heating water loop. To simulate improper balancing, the balancing valves on all the ERS test rooms were 100% open throughout Test Suite 3. Nonetheless, there was no indication during testing that the flow rate to any of the test rooms served by the Siemens valves was above design flow at startup. Figure 4-4b shows that at startup, the three perimeter rooms served by Siemens valves are all receiving approximately 3 GPM (0.19 L/s) of heating water. In a terminal reheat application, the reheat coil provides heat to an airstream entering the room being controlled in an amount that will satisfy the room temperature setpoint. The heating load of the room can be satisfied by a range of heating water flow rates, provided the appropriate temperature difference across the coil can be achieved. As the heating water flow rate increases, the temperature drop of the heating water through the coil decreases. In many systems, there is a tendency at low loads to have higher flow rates coupled with lower temperature drops across the coils. This happens in part because at low loads, the pressure drop introduced by balancing valves in a particular branch is a smaller fraction of the total pressure drop in that branch at design flow. The PICCV is intended to help prevent this situation because the pressure regulator in the valve automatically adjusts to pressure changes in order to provide a constant flow rate for a given commanded signal to the valve. This characteristic of the PICCV is important primarily because lower flow rates translate into less pumping energy. Additionally, higher temperature drops across the reheat coils leads to a lower return water temperature to the hydronic boiler, which is expected to improve the efficiency in newer generation condensing boilers. Table 4-5 provides a summary of the actual “balancing” performance of the Belimo PICCV and the Siemens globe valves for low load conditions in CL 3.3. All data in Table 4-5 are averages obtained by first filtering the data to eliminate any data points that were not considered to be representative of operation at a low load. Filtering retained only data points for which the following conditions were satisfied:

• heating water flow rate is greater than 0.1 GPM (0.006 L/s) and less than 1.0 GPM (0.063 L/s)

• rate of heat transfer from the water is greater than 1000 BTU/h (293 W) and less than 6000 BTU/h (1759 W)

Daily averages obtained from the filtered values were then averaged again to obtain the four-day averages shown in Table 4-5. The columns of data consist of the average heating water temperature drop across the reheat coil, the standard deviation of the temperature drop across the reheat coil, the heating water flow rate, the rate of heat transfer from the heating water, and the number of data points in each data set. Each row in the table represents the results for a different test room. Test rooms utilizing Belimo PICCVs are shaded gray in Table 4-5.

45

Table 4-5: Summary of system balancing performance at low loads for CL 3.3. The A test rooms are served by Belimo PICCV and the B test rooms by Siemens globe valves.

Average Heating Water

Temperature Drop Across Coil

Standard Deviation of Temperature Drop

Across Coil

Heating Water Flow Rate

Rate of Heat Transfer by Heating

Water Room

[°F] [°C] [°F] [°C] [GPM] [L/s] [BTU/h] [W]

No. of Data

Points

East-A 30.0 16.7 4.9 2.7 0.35 0.022 5089.0 1491.6 160 East-B 39.0 21.7 5.9 3.3 0.26 0.016 4817.3 1412.0 225

Interior-A 49.5 27.5 4.9 2.7 0.11 0.007 2699.7 791.3 24 Interior-B 51.6 28.7 5.4 3.0 0.11 0.007 2749.8 806.0 16 South-A 34.4 19.1 6.3 3.5 0.29 0.018 4820.6 1412.9 93 South-B 39.6 22.0 6.1 3.4 0.25 0.016 4719.2 1383.2 245 West-A 30.2 16.8 6.2 3.5 0.35 0.022 5026.6 1473.3 111 West-B 38.4 21.3 7.1 3.9 0.26 0.016 4663.1 1366.8 257

The results in Table 4-5 reveal that the Belimo rooms have consistently higher heating water temperature drops across the reheat coils than the Siemens rooms. The difference on average is 9ºF in the East test rooms, 8.2ºF in the West test rooms, 5.2ºF in the South test rooms, and 2.1ºF in the interior test rooms. The higher temperature drops in the Belimo rooms are coupled with lower average heating water flow rates in comparison to the Siemens rooms, with the difference ranging from 0.11 GPM (0.007 L/s) in the East and West test rooms to essentially no difference in the interior test rooms. Although the magnitude of the difference is small in absolute terms, it represents a reduction in flow rate of as much as 34% at low load conditions. Despite the lower average flow rates achieved in CL 3.3 in the system controlled by the Belimo PICCVs, this test did not reveal any pumping energy savings associated with the use of the PICCVs (see Figure 4-6 for the pumping energy use for one day during CL 3.3). It is important to remember that the design flow rate of the A and B test systems is 10.2 GPM (0.64 L/s), so the differences in the flow rates observed at low loads are small when compared to this. Note that summing the flow rates for all the A test rooms produces an average system flow rate of 1.1 GPM (0.069 L/s) for the Siemens rooms compared to 0.88 GPM (0.056 L/s) for the Belimo rooms. The difference of 0.22 GPM (0.014 L/s) is only 2% of the design flow rate. The lack of pumping energy savings may be due to the fact that testing was performed on a system with a limited number of zones.

4.6 Conclusions The purpose of this suite of tests, designated Test Suite 3, was to compare the system performance characteristics of Belimo PICCVs to correctly sized Siemens Powermite MT globe valves. Based on 19 days of test data, the temperature control of the two valves was comparable, although the Siemens valves were more aggressive and resulted in temperatures that fluctuated around the room setpoint temperature to a greater extent than was seen for the Belimo valves. The difference in the control performance was quantified using the cumulative change in the flow rate. For the perimeter rooms, this parameter was generally two to five times greater for the

46

Siemens valves than for the Belimo valves, indicating superior control on the part of the Belimo valves. There was not a significant difference seen in energy use of the terminal reheat coils controlled by the different brands of valves. The heating water loop pump energy was directly affected by the system differential pressure setpoint. In CL 3.1 and CL 3.2, a higher setpoint was used on the system equipped with Belimo valves and higher energy use resulted. In CL 3.3, the setpoint was the same for the two systems and the energy use was also the same. At low loads, the system equipped with Belimo PICCVs had heating water temperature drops across the reheat coils of the perimeter rooms that were 5 to 9ºF (2.8 to 5ºC) higher than the system with Siemens globe valves with the same system differential setpoint was used for the two heating water loops. The higher temperature drops associated with the Belimo system were accompanied by lower heating water flow rates, although the differences in the flow rates between the Belimo and Siemens systems were small when compared to the design flow rate of the systems. Finally, there was no difference observed in the system startup time between the Belimo and Siemens systems. This finding and the lack of any pumping energy difference may be due in part to the small number of zones served by the ERS test systems and the fact that the ERS systems have a reverse return piping arrangement.

47

5 Air-Handling Unit Chilled Water Open Loop Test The purpose of this suite of tests, designated Test Suite 4, was to evaluate the pressure independent feature of the Belimo PICCV for an AHU chilled water cooling coil application. The tests mimicked Test Suite 1 (see Section 2), which were performed on smaller terminal reheat valves. Like Test Suite 1, the tests described here consisted of measuring the water flow rate through the test valve as a function of valve position and pressure drop across the valve.

5.1 Test Units Testing compared the performance of one Belimo PICCV and one correctly sized Siemens Powermite MT series globe valve and actuator assembly. The selection of the valves was based on a design flow rate of 21 GPM (1.32 L/s). The globe valve was sized to produce a pressure drop of 4 psi (27.6 kPa) with the valve wide open. Detailed specifications for the valve and actuator assemblies are provided in Table 5-1.

5.2 Test Set-Up The test valves were installed on the return line of the chilled water cooling coil in AHU-A. A schematic diagram of the test set-up is shown in Figure 5-1. An Endress Hauser model Cerabar M PMC 41 single-point pressure transducer was installed to measure the valve inlet pressure, and an Endress Hauser model Deltabar S PMD 235 differential pressure transducer was installed

Table 5-1: Specifications for valves used for Test Suite 4 and Test Suite 5.

Designation Belimo PICCV Siemens Powermite MT Manufacturer Belimo Siemens Model PICCV-32-026-PT Powermite MT 599-02046 Type PICCV Globe (Stroke 7/32") Line Size 1-1/4" 1" Cv N/A 10.0 Design Flow Rate 22 GPM (1.39 L/s) N/A

Valve

Close-Off Pressure 200 PSI (1379 kPa) 70 PSI (483 kPa) Manufacturer Belimo Siemens

Model NMQ24-MFT US, GPM 21 SQS65U 264-02046


Force 35 in-lbf (4 N-m) min. torque 90 lbf (400 N) Run-Time 30 seconds 30 seconds Input Signal 0 - 10 VDC 0 - 10 VDC Feedback Output 0 - 10 VDC 0 - 10 VDC

Actuator

Power 24VAC±20%, 24VDC±10% 24VAC, +20%, -15% The valves are normally open and the actuators do not have spring return.

48

AHU-ACHW CoilF

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ACCAHUCHWPTES

- Air Cooled Chiller- Air Handling Unit- Chilled Water Pump- Thermal Energy Storage

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Figure 5-1: Schematic of chilled water loop and instrumentation setup for Test Suite 4.

to measure the pressure drop across the valve. The water flow rate was measured using an existing Brooks Meter model Wafer-MagTM electromagnetic flow meter. The range and accuracy of these instruments are provided below.

• Single-point pressure transducer: Endress Hauser model Cerabar M PMC 41 0 – 100 psig (0 - 689.5 kPa) calibrated span; accuracy of ±0.2 % of calibrated span

• Differential-point pressure transducer: Endress Hauser model Deltabar S PMD 235 0 – 43 psig (0 – 296.5 kPa) calibrated span; accuracy of ±0.1 % of calibrated span

• Flow meter: Brooks Meter model Wafer-MagTM 0 - 18 GPM (0 – 1.14 L/s), accuracy of ±0.09 GPM (±0.0057 L/s); 18-180 GPM (1.14 – 11.4 L/s), accuracy 0.5 % of flow rate plus 0.03 GPM (0.0019 L/s)

A nominal ten ton reciprocating air-cooled chiller was controlled to provide chilled water to the coil at a supply temperature of 45ºF (7.2ºC) throughout Test Suite 4. The chilled water was circulated through a thermal energy storage tank that was charged with ice to smooth temperature fluctuations that are inherent due to compressor cycling. Two pumps arranged in series were used to control the inlet water pressure to the test valve. To minimize pressure fluctuations in the chilled water line, valves connecting other circuits to the chilled water supply main were closed.

49

5.3 Test Conditions and Procedure The PICCV was tested at all combinations of the following conditions:

Commanded Signal to Valve: 10, 15, 20, 25, 30, 35, 40, 60, 80, 95, and 30% open

Differential Pressure Across Valve: 7, 9, 11, 13 and 15 psi The globe valve was tested at all combinations of the following conditions:

Commanded Signal to Valve: 10, 15, 20, 25, 30, 35, 40, 60, 80, 100, and 30% open Differential Pressure Across Valve: 7, 9, 11, 13 and 15 psi

Because the inlet pressure to the valve was controlled and not the differential pressure across the valve, the actual differential pressure varied slightly from the conditions stated above. Note also that the “full open” commanded signal for the PICCV and globe valve differs. For the PICCV, the design flow of 21 GPM (1.32 L/s) was achieved with a control signal of 95% open instead of 100% open. This was a result of coupling the PICCV with the NMQ24-MFT US, GPM 21 actuator. This actuator was selected because it has a 30 second run time, which is the same as the run time of the Siemens actuator. The initial test point was a commanded signal of 10% open and a differential pressure across the valve of 7 psi. The commanded signal was then increased to the next test condition (15% open) while the differential pressure was held constant. Conditions were allowed to stabilize for approximately ten minutes between test points. Testing continued in this way until the valve was fully open. The final test point at a given inlet pressure was a commanded signal of 30% open. This point enabled the hysteresis of the test valve to be evaluated. The tests of the PICCV and globe valve were designated as follows: OL 4.1 – Belimo PICCV OL 4.2 – Siemens Powermite MT

5.4 Instrumentation The following list of measurement and control points were monitored and recorded during the test:

1. Inlet pressure to test valve (psi) 2. Differential pressure across the test valve (psi) 3. Water flow rate (gallons per minute) 4. Commanded signal to test valve (% open) 5. Valve position feedback (% open) 6. Cooling coil entering water temperature (°F) 7. Cooling coil leaving water temperature (temperature at the valve, °F) 8. Chilled water pump speed (% of maximum or Hz)

50

Each of these eight points was recorded at 10 second intervals.

5.5 Results The water flow rate through the Belimo PICCV as a function of the differential pressure across the valve and the commanded signal to the valve is shown in Figure 5-2. The data points in Figure 5-2 and subsequent figures in this chapter are one minute averages obtained from the 10 second data. The curves in Figure 5-2 reveal that the flow rate through the Belimo PICCV is nearly independent of the differential pressure across the valve for a given commanded signal to the valve. This result is consistent with findings reported in Section 2.5 for a smaller PICCV, and the performance expected based on Belimo literature. At the design condition (i.e., commanded signal of 95% open), the flow rate varies from 20.26 GPM at 7 psi to 20.75 GPM at 15 psi (1.28 L/s at 48.3 kPa to 1.31 L/s at 103.4 kPa). The minimum flow rate over this pressure range is 20.01 GPM at 9 psi (1.26 L/s at 62.1 kPa). For a commanded signal of 95% open, the minimum and maximum flows differ by only 3.6% of the average flow corresponding to this commanded signal (20.33 GPM [1.28 L/s]). The largest variation of flow rates relative to the average flow rate at a given commanded signal is 8.5%. This corresponds to a commanded signal of 40% open and an average flow rate of 1.31 GPM (0.083 L/s).


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Figure 5-2: Flow rate through the Belimo PICCV as a function of differential pressure and

commanded signal to the valve.

51

Figure 5-2 contains two curves corresponding to a commanded signal of 30% open. The first curve corresponds to data obtained with the commanded signal increasing from 25% open to 30% open and the second curve (labeled hysteresis data) corresponds to data obtained with the commanded signal decreasing from 95% open to 30% open. The flow rates are significantly different for the two curves (0.57 to 0.62 GPM [0.036 to 0.039 L/s] for the first curve and 1.06 to 1.11 GPM [0.067 to 0.07 L/s] for the second curve). The most likely source of the hysteresis observed in the data is the pressure regulator device in the PICCV, which must respond to pressure changes that occur as the valve is opened and closed. The water flow rate through the Siemens Powermite MT globe valve as a function of the differential pressure across the valve and the commanded signal to the valve is shown in Figure 5-3. The curves in Figure 5-3 indicate that the flow rate through the Siemens valve increases as the differential pressure across the valve increases for a fixed commanded signal to the valve. This is consistent with Siemens literature on the Powermite MT series valve; however, the flow rates measured when the valve was fully open are approximately 21% lower than expected based on Siemens literature. For example, for a differential pressure of 7 psi (48.3 kPa), a flow rate of 20.94 GPM (1.32 L/s) was measured and for a differential pressure of 9 psi (62.1 kPa), a flow rate of 23.57 GPM (1.49 L/s) was measured. The Siemens literature indicates the flow rates should be 26.5 GPM at 7 psi and 30 GPM at 9 psi (1.67 L/s at 48.3 kPa and 1.89 L/s at 62.1 kPa). Based on the measured flow rates, the Siemens valve has a flow coefficient (Cv) of approximately 7.9, whereas the manufacturer stated flow coefficient is 10.0. It was noted


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Figure 5-3: Flow rate through the Siemens Powermite MT globe valve as a function of

differential pressure and commanded signal to the valve.

52

in Section 5.1 that the globe valve was sized to produce a 4 psi (27.6 kPa) pressure drop across the valve when it is fully open. The calculated flow coefficient based on this criteria is Cv = 10.5. The Siemens Powermite MT 599-02046, with a flow coefficient of 10.0, was closest to the desired value of Cv = 10.5. ASHRAE sizing criteria, which states that the control valve pressure drop should be at least 25 to 50 percent of the system loop pressure drop, suggests a valve with a flow coefficient of Cv = 6.8 is appropriate for this application. Thus, based on actual performance, the conventional globe valve performance falls between these two criteria. The Siemens globe valve was tested for hysteresis in the same manner as the Belimo PICCV. At 7 psi (48.3 kPa), a flow rate of 4.7 GPM (0.3 L/s) was obtained with the valve position increasing and a flow rate of 4.52 GPM (0.29 L/s) was obtained with the valve position decreasing. At 15 psi (103.4 kPa), a flow rate of 6.7 GPM (0.42 L/s) was obtained with the valve position increasing and a flow rate of 6.51 GPM (0.41 L/s) was obtained with the valve position decreasing. Thus, the Siemens valve displays very little hysteresis. Figure 5-4 shows a comparison of the flow rates through the Belimo PICCV and Siemens globe valve as a function of the scaled feedback signal from each valve at a differential pressure of 7 psi (48.3 kPa). This plot is similar to Figure 2-6. Once again the Belimo valve was found to have the characteristic of an equal percentage valve, whereas the Siemens valve demonstrated a nearly linear flow characteristic.

Scaled Valve Feedback Signal (% Open)

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Figure 5-4: Flow rate through the Belimo PICCV and Siemens Powermite MT globe valve as a

function of the scaled valve feedback signal at a differential pressure of 7 psi (48.3 kPa).

53

5.6 Conclusions Open-loop tests were conducted to quantify the water flow rate through a Belimo PICCV-32-026-PT and a correctly sized Siemens Powermite MT 599-02046 globe valve as a function of differential pressure across the valve and the commanded signal to the valve. Consistent with the manufacturer’s literature, for a differential pressure range of 7 to 15 psi (48.3 to 103.4 kPa), the flow rate through the Belimo PICCV was nearly independent of differential pressure for a fixed valve position. As expected, the flow rate through the Siemens valve increased as the differential pressure increased for a fixed valve position; however, the flow rate though the Siemens valve with the valve fully open was 21% lower than expected based on the manufacturer’s literature. Based on actual measurements, the Siemens valve has a flow coefficient of 7.9, which falls between the recommended valve size calculated assuming a 4 psi pressure drop across the valve (Cv = 10.5), and the size calculated using ASHRAE sizing criteria (Cv = 6.8). Thus, the Siemens valve should control better than the “correctly” sized valve used in the terminal reheat application, which turned out to be oversized by both sizing criteria. Testing also revealed that the Belimo valve has an equal percentage characteristic curve, while the Siemens valve has a nearly linear characteristic curve.

54

6 Air-Handling Unit Chilled Water Closed Loop Test – Control Performance

The purpose of this suite of tests, which is designated Test Suite 5, was to compare the control performance of the Belimo PICCV to a conventional globe valve for a chilled water cooling coil application. The test evaluated various control characteristics, such as stability and ability to maintain the supply air temperature at the setpoint, as scheduled disturbances were imposed on the cooling coil and control valve.

6.1 Test Units Testing compared the performance of one Belimo PICCV and one Siemens Powermite MT series globe valve and actuator assembly. The same valves used in Test Suite 4 were used for this test. Detailed specifications for the valve and actuator assemblies are provided in Table 5-1.

6.2 Test Set-Up Figure 6-1 is a schematic of the test set-up for the closed loop testing. The Belimo PICCV and Siemens Powermite test valves were installed and tested simultaneously on the return side of the chilled water cooling coils in AHU-A and AHU-B. The instrumentation used to measure the inlet pressure to the valves, differential pressure across the valves, and chilled water flow rate through the valves are identical to those used in Test Suite 4. Range and accuracy specifications for these instruments are provided in Section 5.2. Chilled water was provided to each cooling coil by a single 10-ton reciprocating air-cooled chiller. To minimize temperature fluctuations, the chilled water was circulated through a charged thermal energy storage (TES) tank prior to its distribution to the AHUs. The TES mixing valve shown in Figure 6.1 was controlled to produce chilled water at 44ºF (6.7ºC). The secondary loop circulating pumps, AHU-A CHWP and AHU-B CHWP, operated at constant speed. The primary chilled water pump (CHWP-CH) was operated according to a fixed schedule that is described in the next section. To minimize uncontrolled pressure disturbances, other chillers and AHUs that tie into the piping network shown in Figure 6.1 were isolated from the system by closing manual valves. Throughout Test Suite 5, the test rooms were controlled in a manner that produced uniform and equal air conditions at the inlet to the cooling coils for AHU-A and AHU-B. This was accomplished through the following set-up:

• The heating setpoint and cooling setpoint for all test rooms was 71.6ºF (22ºC) and 73.4ºF (23ºC), respectively;

• The return dampers in each test room were closed and the test room doors were opened to force the test room air to mix with the air in the rest of the building;

• The AHU dampers were set for 100% recirculated air (i.e., no outdoor air); and • Well mixed air from the building was drawn into AHU-A and AHU-B through access

doors located upstream of the cooling coil.

55

AHU-ACHW CoilF

P T

T

W

AHU-A CHWP

AHU-BCHW CoilF

PW

AHU-B CHWP

TES Tank

T

ACC - CH10 Ton

AA

P

TTT

CH

WR

-CH

CHWS-CH

TES MixingValveTES Bypass

ValveW

VFD

ACCAHUCHWPTES

- Air Cooled Chiller- Air Handling Unit- Chilled Water Pump- Thermal Energy Storage

A

F

P

T

W

VFD

- Actuator (Analog)- Differential Pressure Sensor- Flow Meter- Pressure Sensor- Temperature Sensor- Watt Meter- Variable Frequency Drive

LEGEND

T

A

P

T

TA

PDP

CH

WS-

CH

F

Test Valve: - CL 5.1: Globe Valve - CL 5.2: PICCV

Test Valve: - CL 5.1: PICCV - CL 5.2: Globe Valve

DP

CHWP-CH

DP

Figure 6-1: Schematic of chilled water system and instrumentation setup for Test Suite 5.

In addition, to minimize load variations in the test room loads, all testing was performed at night.

6.3 Test Conditions and Procedure In each test conducted in Test Suite 5, the test valve was controlled by a proportional-integral control algorithm running inside a Johnson Controls DCM 140 controller. The test valve modulates the flow of chilled water through the valve to maintain the supply air temperature at a setpoint value according to the control sequence in the controller. Controller gains used at the ERS for supply air temperature control for summer conditions were utilized for both test valves. Values of the controller gains are provided below:

• Proportional Band: -45.7 • Integral Time: 120 s

Throughout the test, the occupied minimum and maximum airflow rate to each perimeter test room was set equal to 700 CFM (330.4 L/s), and the occupied minimum and maximum airflow

56

rate to each interior room was set equal to 300 CFM (141.6 L/s). The result was a total airflow rate across each cooling coil of 2400 CFM (1132.7 L/s). Figure 6-2 shows the disturbance schedule utilized for Test Suite 5. The intent of the disturbances was to force the chilled water valves to operate over a significant range and to respond to changing pressure conditions. The supply air temperature setpoint was initially 56ºF (13.3ºC) and the value was increased by 4ºF (2.2ºC) at 100 minute intervals until it reached 68ºF (20.0ºC). To simulate pressure fluctuations that are typical in a chilled water loop serving multiple air-handling units, the speed of the primary chilled water pump (CHWP-CH) was varied at 25 minute intervals from 85% to 70%, then to 100%, and finally back to 85%. This cycle was repeated every 100 minutes when the supply air temperature setpoint was changed.

6.4 Instrumentation The following measurement and control points were monitored and recorded at 10 second intervals during the test:

1. Inlet pressure to test valve (psi) 2. Differential pressure across the test valve (psi) 3. Water flow rate through cooling coil (gallons per minute) 4. Control signal to test valve (% open) 5. Valve position feedback (% open)

In addition, all the measurement and control points normally collected at the ERS, including the points above, were recorded at 1-minute intervals.

6.5 Results To obtain a meaningful comparison of the test valves, it is important that the air and chilled water conditions entering the cooling coils of AHU-A and AHU-B are the same. The entering air conditions of relevance are the temperature, relative humidity, and airflow rate. The entering air temperature and relative humidity to the chilled water cooling coils was expected to be the same since each AHU draws its air from the mechanical room through an access panel upstream of the

Time (h)

0 1 2 3 4 5 6 7

Sup

ply

Air T

empe

ratu

re S

etpo

int (

F)

50

55

60

65

70

75

Supp

ly A

ir Te

mpe

ratu

re S

etpo

nit (

C)

10

12

14

16

18

20

22

Time (h)

0 1 2 3 4 5 6 7

Prim

ary

Chi

lled

Wat

er P

ump

Spe

ed(%

of M

axim

um)

65

70

75

80

85

90

95

100

Figure 6-2: Supply air temperature setpoint and primary chilled water pump speed profiles for

CL 5.1 and CL 5.2.

57

cooling coil (see Section 6.2 for a description of the test setup). Therefore, any differences in temperature or relative humidity would be due to poor mixing of the air in the mechanical room and/or localized heat or moisture sources or sinks. The airflow rates across the cooling coils of AHU-A and AHU-B were expected to be the same since the AHUs were controlled to provide constant and equal airflow rates to the test rooms (see Section 6.2). The entering water conditions were expected to be the same since both AHUs receive chilled water from a common supply header. Thus, any differences in conditions would be due to differences in heat gain between the supply header and the respective AHU cooling coils. Since the chilled water piping is insulated, these differences were expected to be insignificant. The chilled water cooling coil entering air temperatures, airflow rates, and entering water temperatures for Test CL 5.1 are shown in Figures 6-3 through 6-5. The mean values and standard deviations of the entering air temperature to the cooling coils are 72.41ºF and 0.21ºF (22.45ºC and 0.12ºC) for AHU-A, and 72.17ºF and 0.27ºF (22.32ºC and 0.15ºC) for AHU-B. The mean values and standard deviations of the sum of the airflow rates to the test rooms (assumed to be equal to the airflow rate across the cooling coil) are 2399.9 CFM and 5.0 CFM (1132.6 L/s and 2.4 L/s) for AHU-A, and 2399.9 CFM and 9.1 CFM (1132.6 L/s and 4.3 L/s) for

Time (h)

0 1 2 3 4 5 6 7

Coo

ling

Coi

l Ent

erin

g A

ir Te

mpe

ratu

re (F

)

70

71

72

73

74

75

Coo

ling

Coi

l Ent

erin

g A

ir Te

mpe

ratu

re (C

)

21.5

22.0

22.5

23.0

23.5

PICCV (AHU-A)

Globe Valve (AHU-B)

Figure 6-3: Chilled water cooling coil entering air temperatures for CL 5.1.

Time (h)

0 1 2 3 4 5 6 7

Sum

of R

oom

Airf

low

Rat

es (C

FM)

2370

2380

2390

2400

2410

2420

2430

Sum

of R

oom

Airf

low

Rat

es (L

/s)

1120

1125

1130

1135

1140

1145

Figure 6-4: Airflow rates across the chilled water cooling coils for CL 5.1

58

Time (h)

0 1 2 3 4 5 6 7C

hille

d W

ater

Ent

erin

g Te

mpe

ratu

re (F

)

40

41

42

43

44

45

46

47

48

49

50

Chi

lled

Wat

er E

nter

ing

Tem

pera

ture

(C)

5

6

7

8

9

10

Globe Valve(AHU-B)

PICCV (AHU-A)

Figure 6-5: Chilled water cooling coil entering water temperatures for CL 5.1.

AHU-B. Finally, the mean values and standard deviations of the entering water temperature to the cooling coils are 43.18ºF and 0.89ºF (6.21ºC and 0.49ºC) for AHU-A, and 43.33ºF and 0.80ºF (6.29ºC and 0.44ºC) for AHU-B. These results show that the entering conditions to the cooling coils for AHU-A and AHU-B are in close agreement. Similar results were obtained for CL 5.2. A comparison of the chilled water cooling coil entering air relative humidity is not provided because this measurement was not available on AHU-B. However, because both AHUs draw air from the mechanical room, the assumption that the entering air relative humidity was the same for each AHU is justified. Plots of the control response and performance parameters for CL 5.1 are shown in Figures 6-6 through 6-14. Figures 6-6 and 6-7 are plots of the control (commanded) and scaled feedback signals to the valves, respectively. The response of the Belimo PICCV to the setpoint and pressure changes is evident in the plots. Decreases in the control signal are associated with increases in the supply air temperature setpoint and increases in the primary chilled water pump speed, whereas increases in the control signal are associated with reductions in the primary chilled water pump speed. The PICCV has a stable control and feedback signal over the entire test. The Siemens valve exhibits stable control initially; however, as the valve approaches a fully closed position, the control signal begins to oscillate. The feedback signal for the Siemens valve captures the oscillations initially, however, it indicates the valve is essentially closed from hour five forward (there is little or no change in the feedback signal), which corresponds to a supply air temperature of 68ºF (20ºC). Figure 6-8 and 6-9 are plots of the chilled water flow rate and supply air temperature control for CL 5.1. Figure 6-8a shows that the Belimo PICCV provides stable flow throughout the test, including at flow rates as low as 0.99 GPM (0.062 L/s). This leads to stable control of the supply air temperature with one or two minor overshoots and undershoots at each setpoint value, as seen in Figure 6-9a. On the other hand, it can be seen in Figure 6-8b that the flow through the Siemens valve is very unstable at flow rates below 4 GPM (0.252 L/s). The impact of unstable flow rate can be seen in the supply air temperature control in Figure 6-9b. The supply air temperature corresponding to the Siemens valve oscillates significantly at the low load conditions simulated by increasing the supply air temperature setpoint to 64ºF (17.78ºC) and then 68ºF (20ºC). Finally, although the feedback signal from the Siemens valve indicates it is

59

Time (h)

0 1 2 3 4 5 6 7

Con

trol S

igna

l (%

Ope

n)

0

10

20

30

40

50

60

70

80

90

100

Time (h)

0 1 2 3 4 5 6 7

Con

trol S

igna

l (%

Ope

n)

0

10

20

30

40

50

60

70

80

90

100

(a) AHU-A: Belimo (b) AHU-B: Siemens

Figure 6-6: Chilled water cooling coil valve control signal for CL 5.1.

Time (h)

0 1 2 3 4 5 6 7

Val

ve F

eedb

ack

Sig

nal (

% O

pen)

0

10

20

30

40

50

60

70

80

90

100

Time (h)

0 1 2 3 4 5 6 7

Sca

led

Val

ve F

eedb

ack

Sig

nal (

% O

pen)

0

10

20

30

40

50

60

70

80

90

100


Figure 6-7: Chilled water cooling coil valve feedback signal for CL 5.1.

Time (h)

0 1 2 3 4 5 6 7

Chi

lled

Wat

er F

low

Rat

e (G

PM)

0

1

2

3

4

5

6

7

89

10

11

12

Chi

lled

Wat

er F

low

Rat

e (L

/s)

0.0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

Time (h)

0 1 2 3 4 5 6 7

Chi

lled

Wat

er F

low

Rat

e (G

PM)

0

1

2

3

4

5

6

7

89

10

11

12

Chi

lled

Wat

er F

low

Rat

e (L

/s)

0.0

0.1

0.2

0.3

0.4

0.5

0.6

0.7


Figure 6-8: Chilled water flow rate for CL 5.1.

60

Time (h)

0 1 2 3 4 5 6 7

Sup

ply

Air T

empe

ratu

re (F

)

50

55

60

65

70

75

Sup

ply

Air T

empe

ratu

re (C

)

10

12

14

16

18

20

22

Measurement

Setpoint

Time (h)

0 1 2 3 4 5 6 7

Sup

ply

Air T

empe

ratu

re (F

)

50

55

60

65

70

75

Sup

ply

Air T

empe

ratu

re (C

)

10

12

14

16

18

20

22

MeasurementSetpoint


Figure 6-9: Supply air temperature control for CL 5.1.

Time (h)

0 1 2 3 4 5 6 7

Accu

mul

ated

Abs

olut

e Va

lue

of S

uppl

y Ai

r Tem

pera

ture

Err

or (F

-min

)

0

50

100

150

200

250

Accu

mul

ated

Abs

olut

e Va

lue

of S

uppl

y Ai

r Tem

pera

ture

Err

or (C

-min

)

0

20

40

60

80

100

120

Globe Valve

PICCV

Figure 6-10: Accumulated supply air


Time (h)

0 1 2 3 4 5 6 7

Acc

umul

ated

Act

uato

r Tra

vel

0

20

40

60

80

100

120

140

160

180

200

PICCV

Globe Valve


travel for CL 5.1.

Time (h)

0 1 2 3 4 5 6 7

Sta

rts a

nd S

tops

0

25

50

75

100

125

150

175

200

225

250

PICCV

Globe Valve

Figure 6-12: Accumulated starts and

stops for CL 5.1.

Time (h)

0 1 2 3 4 5 6 7

Rev

ersa

ls

0

10

20

30

40

50

60

70

80

90

100

PICCV

Globe Valve


for CL 5.1.

61

Time (h)

0 1 2 3 4 5 6 7

Cum

ulat

ive

Cha

nge

in F

low

Rat

e (G

PM

)

0

50

100

150

200

250

300

350

400

450

500

Cum

ulat

ive

Cha

nge

in F

low

Rat

e (L

/s)

0

5

10

15

20

25

30

PICCV

Globe Valve

Figure 6-14: Cumulative change in chilled

water flow rate for CL 5.1. essentially closed at a supply air temperature setpoint of 68ºF (20ºC), Figures 6-8b and 6-9b prove that the valve position is changing during this period because the chilled water flow rate and supply air temperature are obviously changing. Figures 6-10 through 6-14 are plots of the accumulated supply air temperature error (defined by Equation 2 in Section 3.5, where the temperature error of interest in Test Suite 5 is the difference between the supply air temperature setpoint and the supply air temperature), accumulated actuator travel (Equation 3), actuator starts and stops, actuator reversals, and the cumulative change in the chilled water flow rate (Equation 4). The accumulated supply air temperature error indicates that the control performance of the two valves is comparable. Although the supply air temperature affected by the Siemens valve (AHU-B) oscillated significantly at low loads, it was very responsive to setpoint changes, as evidenced by the fact that the temperature response curve almost lies on top of the setpoint curve when the setpoint changes. The Belimo PICCV is less responsive than the Siemens valve to setpoint changes and, as noted previously, the PICCV also overshoots and undershoots once or twice at each setpoint value and generally does not completely eliminate the error at a given setpoint value. The other control performance parameters in Figures 6-11 through 6-14 reveal that the Belimo PICCV has a superior control performance to the Siemens valve. Note that the Siemens actuator travel, starts and stops, and reversals all plateau near the end of the test. This is because the calculation of these parameters is based on the feedback signal and the Siemens feedback signal indicates the valve is essentially closed from hour five forward (see Figure 6-7b). Nonetheless, the control performance parameters corresponding to the Belimo PICCV are smaller than those of the Siemens valve, indicating superior performance by the PICCV. For instance, the Belimo PICCV has 37% less actuator travel and nearly six times fewer reversals than the Siemens valve. The cumulative change in the water flow rate is calculated directly from measurements of the flow rate and, therefore, is not affected by the valve feedback signal. The value corresponding to the Siemens valve is more than four times that of the Belimo PICCV. Note that the slope of the curve corresponding to the Siemens valve changes significantly midway through the test. This is due to the onset of the oscillations in the flow rate.

62

A complete set of plots for CL 5.1 and CL 5.2, including the inlet pressure to the valves and differential pressure across the valves, is provided in Appendix C. Table 6-1 provides a summary of the control performance results for Test Suite 5. The control performance is characterized by the average temperature error (defined by Equation 1 of Section 3.5, where the temperature error of interest in Test Suite 5 is the difference between the supply air temperature setpoint and the supply air temperature), average absolute value of the temperature error (Equation 2), accumulated actuator travel (Equation 3), actuator reversals, actuator starts and stops, and the cumulative change in the chilled water flow rate (Equation 4). Table 6-1 indicates that the control performance of the valves is comparable when the temperature errors are considered. The Siemens valve had a smaller average temperature error (by approximately 0.03ºF); however, the average absolute value of the temperature error was larger for the Siemens valve (by approximately 0.06ºF) due to the oscillatory response at low flow rates. These results support the conclusion that the Siemens valve is more responsive and the Belimo PICCV is more stable. This conclusion is also supported by the results for the number of actuator reversals and the cumulative change in the chilled water flow rate. The Siemens valve makes three to six times more reversals than the Belimo valve, and the cumulative change in water flow rate associated with the Siemens valve is four or more times that for the Belimo PICCV. The results for CL 5.2 for the actuator travel and number of starts and stops appear to challenge the conclusion that the Belimo PICCV is more stable than the Siemens valve. For this test, the actuator travel and actuator starts and stops for the Belimo PICCV exceed those of the Siemens valve. For actuator travel, this is due to the fact that the feedback signal from the Siemens valve indicates it is closed for the last 100 minutes of the test, so the travel parameter stops increasing. Finally, for Test Suite 5, the actuator starts and stops do not appear to be an effective parameter for evaluating control performance. Improved control at low flow rates observed for the Belimo PICCV is expected to lead to a higher temperature rise on average across the chilled water cooling coil, and a lower chilled water flow rate on average through the coil. Lower chilled water flow rates result in lower pumping energy. The temperature rise across the cooling coil for CL 5.1 and CL 5.2 is shown in Figure 6-15. The chilled water flow rate, averaged at 25 minute intervals (i.e., every 25 minutes,

Table 6-1: Summary of control performance parameters for Test Suite 5.

Average Temperature

Error 1

Average Absolute Value of Temperature

Error 1

Cumulative Change in Water

Flow Rate Test Valve

[ºF] [ºC] [ºF] [ºC]

Accumu-lated

Actuator Travel

[%]

Actuator Reversals

Actuator Starts

and Stops [GPM] [L/s]

Belimo 0.087 0.048 0.43 0.24 118.8 17 232 106.0 6.69 CL 5.1

Siemens 0.050 0.028 0.50 0.28 188.2 98 246 465.9 29.39

Belimo 0.086 0.048 0.41 0.23 109.1 15 206 98.8 6.23 CL 5.2

Siemens 0.059 0.033 0.46 0.26 98.5 44 126 398.2 25.12

63

Time (h)

0 1 2 3 4 5 6 7

Tem

pera

ture

Ris

e A

cros

s C

oolin

g C

oil (

F)

10

12

14

16

18

20

22

24

26

28

30

Tem

pera

ture

Ris

e Ac

ross

Coo

ling

Coi

l (C

)

6

7

8

9

10

11

12

13

14

15

16

PICCV(AHU-A)

Globe Valve(AHU-B)

Time (h)

0 1 2 3 4 5 6 7

Tem

pera

ture

Ris

e A

cros

s C

oolin

g C

oil (

F)

10

12

14

16

18

20

22

24

26

28

30

Tem

pera

ture

Ris

e Ac

ross

Coo

ling

Coi

l (C

)

6

7

8

9

10

11

12

13

14

15

16

PICCV(AHU-B)

Globe Valve(AHU-A)

(a) CL 5.1 (b) CL 5.2

Figure 6-15: Temperature rise across the chilled water cooling coil for CL 5.1 and CL 5.2.

a new average is computed based on the previous 25 minutes of data), is shown in Figure 6-16. The secondary pumping power for CL 5.1 and CL 5.2 is shown in Figure 6-17. The plots in Figure 6-15 indicate that the cooling coil equipped with the PICCV (AHU-A in CL 5.1 and AHU-B in CL 5.2) has a higher temperature rise across the cooling coil over the second half of the test, which corresponds to low load (i.e., low flow rates) conditions. However, the average chilled water flow rates at low flow conditions are nearly indistinguishable for the two valves. Furthermore, the pumping energy indicates that the secondary pump for AHU-A uses approximately 5 to 7% less energy than the secondary pump for AHU-B, regardless of which valves are installed in AHU-A and AHU-B. Thus, although the Belimo PICCV demonstrates more stable control than the Siemens valve, any pumping energy savings resulting from the improved control performance is not distinguishable in this test.

6.6 Conclusions The purpose of this suite of tests, designated Test Suite 5, was to compare the control performance of the Belimo PICCV-32-026-PT and a Siemens Powermite MT 599-02046 globe valve for a chilled water cooling coil application. Control performance was evaluated in terms of the temperature control, actuator travel, actuator starts and stops, actuator reversals, and the cumulative change in the water flow rate as disturbances were introduced via changes to the supply air temperature setpoint and primary chilled water pump speed. The test was performed twice, first with the Belimo PICCV installed in AHU-A and the Siemens valve in AHU-B for CL 5.1, and then with the Siemens valve installed in AHU-A and the Belimo PICCV in AHU-B for CL 5.2. In both CL 5.1 and CL 5.2, the Belimo PICCV exhibited stable control over the entire test and was capable of providing stable flow as low as 0.99 GPM (0.062 L/s), whereas the Siemens valve exhibited unstable control at flow rates below 4 GPM (0.252 L/s). The inability of the Siemens valve to provide stable flow at low loads resulted in significantly higher values of

64

Time (h)

0 1 2 3 4 5 6 7

Aver

age

Chi

lled

Wat

er F

low

Rat

e (G

PM

)

0

1

2

3

4

5

6

7

89

10

11

12

Aver

age

Chi

lled

Wat

er F

low

Rat

e (L

/s)

0.0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

Globe Valve(AHU-B)

PICCV (AHU-A)

Time (h)

0 1 2 3 4 5 6 7

Aver

age

Chi

lled

Wat

er F

low

Rat

e (G

PM

)

0

1

2

3

4

5

6

7

89

10

11

12

Aver

age

Chi

lled

Wat

er F

low

Rat

e (L

/s)

0.0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

Globe Valve(AHU-A)

PICCV(AHU-B)

(a) CL 5.1 (b) CL 5.2

Figure 6-16: Averaged chilled water flow rate for CL 5.1 and CL 5.2.

Time (h)

0 1 2 3 4 5 6 7

Sec

onda

ry C

hille

d W

ater

Pum

p P

ower

(W)

250

260

270

280

290

300

310

320

330

340

Globe Valve(AHU-B)

PICCV(AHU-A)

Time (h)

0 1 2 3 4 5 6 7

Sec

onda

ry C

hille

d W

ater

Pum

p P

ower

(W)

250

260

270

280

290

300

310

320

330

340

Globe Valve(AHU-A)

PICCV (AHU-B)

(a) CL 5.1 (b) CL 5.2

Figure 6-17: Secondary chilled water pump power for CL 5.1 and CL 5.2.

certain control performance parameters compared to the Belimo valve. For instance, the Siemens valve made three to six times more reversals than the Belimo valve, and the cumulative change in water flow rate associated with the Siemens valve was four or more times that for the Belimo PICCV. The temperature control of the Belimo and Siemens valves was similar, with the exception occurring for operation at low flow rates, where unstable flow rates associated with the Siemens valve led to unstable supply air temperatures. In addition, although the Belimo PICCV demonstrated more stable control than the Siemens valve and produced slightly higher temperature rises across the cooling coil at low load conditions, any pumping energy savings resulting from the improved control performance was not distinguishable in this test.

65

A. Appendix A: Test Suite 2 Results A.1. Plotted Results for CL 2.1 Summary of CL 2.1:

• Room air temperature control with constant inlet pressure to control valve and variable heating water loop pump speed.

• Belimo PICCV-15-003 installed in South-A test room. • Siemens Powermite MT 599-02036 (Cv = 1.6) installed in South-B test room.

Time (h)

0 1 2 3 4 5 6 7 8 9 10 11

Con

trol S

igna

l (%

Ope

n)

0

10

20

30

40

50

60

70

80

90

100

Time (h)

0 1 2 3 4 5 6 7 8 9 10 11

Con

trol S

igna

l (%

Ope

n)

0

10

20

30

40

50

60

70

80

90

100

(a) Belimo (b) Siemens

Figure A-1: Valve control signal for CL 2.1.

Time (h)

0 1 2 3 4 5 6 7 8 9 10 11

Valv

e Fe

edba

ck S

igna

l (%

Ope

n)

0

10

20

30

40

50

60

70

80

90

100

Time (h)

0 1 2 3 4 5 6 7 8 9 10 11

Scal

ed V

alve

Fee

dbac

k S

igna

l (%

Ope

n)

0

10

20

30

40

50

60

70

80

90

100


Figure A-2: Valve position feedback signal for CL 2.1.

66

Time (h)

0 1 2 3 4 5 6 7 8 9 10 11

Hea

ting

Wat

er F

low

Rat

e (G

PM

)

0

1

2

3

4

5

6

Hea

ting

Wat

er F

low

Rat

e (L

/s)

0.00

0.05

0.10

0.15

0.20

0.25

0.30

0.35

Time (h)

0 1 2 3 4 5 6 7 8 9 10 11

Hea

ting

Wat

er F

low

Rat

e (L

/s)

0.00

0.05

0.10

0.15

0.20

0.25

0.30

0.35

Hea

ting

Wat

er F

low

Rat

e (G

PM

)

0

1

2

3

4

5

6


Figure A-3: Heating water flow rate for CL 2.1.

Time (h)

0 1 2 3 4 5 6 7 8 9 10 11

Roo

m A

ir Te

mpe

ratu

re (F

)

70

71

72

73

74

75

Roo

m A

ir Te

mpe

ratu

re (C

)

21.5

22.0

22.5

23.0

23.5

Measurement

Setpoint

Time (h)

0 1 2 3 4 5 6 7 8 9 10 11

Roo

m A

ir Te

mpe

ratu

re (F

)

70

71

72

73

74

75

Roo

m A

ir Te

mpe

ratu

re (C

)

21.5

22.0

22.5

23.0

23.5

Measurement

Setpoint


Figure A-4: Room temperature control for CL 2.1.

Time (h)

0 1 2 3 4 5 6 7 8 9 10 11

Roo

m A

irflo

w R

ate

(CFM

)

0

100

200

300

400

500

600

700

800

900

1000

Roo

m A

irflo

w R

ate

(L/s

)

0

50

100

150

200

250

300

350

400

450

Setpoint

Measurement

Time (h)

0 1 2 3 4 5 6 7 8 9 10 11

Roo

m A

irflo

w R

ate

(CFM

)

0

100

200

300

400

500

600

700

800

900

1000

Roo

m A

irflo

w R

ate

(L/s

)

0

50

100

150

200

250

300

350

400

450

Setpoint

Measurement


Figure A-5: Room airflow control for CL 2.1.

67

Time (h)

0 1 2 3 4 5 6 7 8 9 10 11

Inle

t Pre

ssur

e to

Val

ve (p

si)

20

22

24

26

28

30

32

Inle

t Pre

ssur

e to

Val

ve (k

Pa)

140

150

160

170

180

190

200

210

220

PICCV

Globe Valve

Figure A-6: Inlet pressure to

valve for CL 2.1.

Time (h)

0 1 2 3 4 5 6 7 8 9 10 11

Diff

eren

tial P

ress

ure

Acr

oss

Val

ve (p

si)

0

2

4

6

8

10

12

Diff

eren

tial P

ress

ure

Acr

oss

Valv

e (k

Pa)

0

10

20

30

40

50

60

70

80

Globe Valve

PICCV

Figure A-7: Differential pressure

across valve for CL 2.1.

Time (h)

0 1 2 3 4 5 6 7 8 9 10 11

Acc

umul

ated

Abs

olut

e V

alue

of R

oom

Tem

pera

ture

Err

or (F

-min

)

0

50

100

150

200

250

Acc

umul

ated

Abs

olut

e V

alue

of R

oom

Tem

pera

ture

Err

or (C

-min

)

0

20

40

60

80

100

120

Globe Valve

PICCV

Figure A-8: Accumulated room


Time (h)

0 1 2 3 4 5 6 7 8 9 10 11

Acc

umul

ated

Act

uato

r Tra

vel

0

500

1000

1500

2000

2500

3000

3500

4000

4500

5000

5500

6000

PICCV

Globe Valve

Figure A-9: Accumulated actuator

travel for CL 2.1.

Time (h)

0 1 2 3 4 5 6 7 8 9 10 11

Star

ts a

nd S

tops

0

200

400

600

800

1000

1200

1400

1600

1800

2000

PICCV

Globe Valve

Figure A-10: Accumulated starts


Time (h)

0 1 2 3 4 5 6 7 8 9 10 11

Rev

ersa

ls

0

200

400

600

800

1000

1200

1400

1600

1800

2000

PICCV

Globe Valve

Figure A-11: Accumulated

reversals for CL 2.1.

68

A.2. Plotted Results for CL 2.2 Summary of CL 2.2:



Time (h)

0 1 2 3 4 5 6 7 8 9 10 11

Con

trol S

igna

l (%

Ope

n)

0

10

20

30

40

50

60

70

80

90

100

Time (h)

0 1 2 3 4 5 6 7 8 9 10 11

Con

trol S

igna

l (%

Ope

n)

0

10

20

30

40

50

60

70

80

90

100



Time (h)

0 1 2 3 4 5 6 7 8 9 10 11

Val

ve F

eedb

ack

Sig

nal (

% O

pen)

0

10

20

30

40

50

60

70

80

90

100

Time (h)

0 1 2 3 4 5 6 7 8 9 10 11

Sca

led

Val

ve F

eedb

ack

Sig

nal (

% O

pen)

0

10

20

30

40

50

60

70

80

90

100



69

Time (h)

0 1 2 3 4 5 6 7 8 9 10 11

Hea

ting

Wat

er F

low

Rat

e (G

PM

)

0

1

2

3

4

5

6

Hea

ting

Wat

er F

low

Rat

e (L

/s)

0.00

0.05

0.10

0.15

0.20

0.25

0.30

0.35

Time (h)

0 1 2 3 4 5 6 7 8 9 10 11

Hea

ting

Wat

er F

low

Rat

e (L

/s)

0.00

0.05

0.10

0.15

0.20

0.25

0.30

0.35

Hea

ting

Wat

er F

low

Rat

e (G

PM)

0

1

2

3

4

5

6



Time (h)

0 1 2 3 4 5 6 7 8 9 10 11

Roo

m A

ir Te

mpe

ratu

re (F

)

70

71

72

73

74

75

Roo

m A

ir Te

mpe

ratu

re (C

)

21.5

22.0

22.5

23.0

23.5

Measurement

Setpoint

Time (h)

0 1 2 3 4 5 6 7 8 9 10 11

Roo

m A

ir Te

mpe

ratu

re (F

)

70

71

72

73

74

75

Roo

m A

ir Te

mpe

ratu

re (C

)

21.5

22.0

22.5

23.0

23.5

Measurement

Setpoint



Time (h)

0 1 2 3 4 5 6 7 8 9 10 11

Roo

m A

irflo

w R

ate

(CFM

)

0

200

400

600

800

1000

Roo

m A

irflo

w R

ate

(l/s)

0

100

200

300

400

Setpoint

Measurement

Time (h)

0 1 2 3 4 5 6 7 8 9 10 11

Roo

m A

irflo

w R

ate

(CFM

)

0

200

400

600

800

1000

Roo

m A

irflo

w R

ate

(l/s)

0

100

200

300

400

Setpoint

Measurement



70

Time (h)

0 1 2 3 4 5 6 7 8 9 10 11

Inle

t Pre

ssur

e to

Val

ve (p

si)

20

22

24

26

28

30

32

Inle

t Pre

ssur

e to

Val

ve (k

Pa)

140

150

160

170

180

190

200

210

220

PICCV

Globe Valve


valve for CL 2.2.

Time (h)

0 1 2 3 4 5 6 7 8 9 10 11

Diff

eren

tial P

ress

ure

Acr

oss

Val

ve (p

si)

0

2

4

6

8

10

12

Diff

eren

tial P

ress

ure

Acr

oss

Valv

e (k

Pa)

0

10

20

30

40

50

60

70

80

PICCV

Globe Valve



Time (h)

0 1 2 3 4 5 6 7 8 9 10 11

Acc

umul

ated

Abs

olut

e V

alue

of R

oom

Tem

pera

ture

Err

or (F

-min

)

0

50

100

150

200

250

Acc

umul

ated

Abs

olut

e V

alue

of R

oom

Tem

pera

ture

Err

or (C

-min

)

0

20

40

60

80

100

120

Globe Valve

PICCV



Time (h)

0 1 2 3 4 5 6 7 8 9 10 11

Acc

umul

ated

Act

uato

r Tra

vel

0

50010001500

2000

250030003500

40004500

500055006000

PICCV

Globe Valve


travel for CL 2.2.

Time (h)

0 1 2 3 4 5 6 7 8 9 10 11

Star

ts a

nd S

tops

0

200

400

600

800

1000

1200

1400

1600

1800

2000

PICCV

Globe Valve



Time (h)

0 1 2 3 4 5 6 7 8 9 10 11

Rev

ersa

ls

0

200

400

600

800

1000

1200

1400

1600

1800

2000

PICCV

Globe Valve



71




Time (h)

0 1 2 3 4 5 6 7 8 9 10 11

Con

trol S

igna

l (%

Ope

n)

0

10

20

30

40

50

60

70

80

90

100

Time (h)

0 1 2 3 4 5 6 7 8 9 10 11

Con

trol S

igna

l (%

Ope

n)

0

10

20

30

40

50

60

70

80

90

100



Time (h)

0 1 2 3 4 5 6 7 8 9 10 11

Val

ve F

eedb

ack

Sig

nal (

% O

pen)

0

10

20

30

40

50

60

70

80

90

100

Time (h)

0 1 2 3 4 5 6 7 8 9 10 11

Sca

led

Val

ve F

eedb

ack

Sig

nal (

% O

pen)

0

10

20

30

40

50

60

70

80

90

100



72

Time (h)

0 1 2 3 4 5 6 7 8 9 10 11

Hea

ting

Wat

er F

low

Rat

e (G

PM

)

0

1

2

3

4

5

6

Hea

ting

Wat

er F

low

Rat

e (L

/s)

0.00

0.05

0.10

0.15

0.20

0.25

0.30

0.35

Time (h)

0 1 2 3 4 5 6 7 8 9 10 11

Hea

ting

Wat

er F

low

Rat

e (L

/s)

0.00

0.05

0.10

0.15

0.20

0.25

0.30

0.35

Hea

ting

Wat

er F

low

Rat

e (G

PM

)

0

1

2

3

4

5

6



Time (h)

0 1 2 3 4 5 6 7 8 9 10 11

Roo

m A

ir Te

mpe

ratu

re (F

)

70

71

72

73

74

75

Roo

m A

ir Te

mpe

ratu

re (C

)

21.5

22.0

22.5

23.0

23.5

Measurement

Setpoint

Time (h)

0 1 2 3 4 5 6 7 8 9 10 11

Roo

m A

ir Te

mpe

ratu

re (F

)

70

71

72

73

74

75

Roo

m A

ir Te

mpe

ratu

re (C

)

21.5

22.0

22.5

23.0

23.5

Measurement

Setpoint



Time (h)

0 1 2 3 4 5 6 7 8 9 10 11

Roo

m A

irflo

w R

ate

(CFM

)

0

200

400

600

800

1000

Roo

m A

irflo

w R

ate

(L/s

)

0

100

200

300

400

Setpoint

Measurement

Time (h)

0 1 2 3 4 5 6 7 8 9 10 11

Roo

m A

irflo

w R

ate

(CFM

)

0

200

400

600

800

1000

Roo

m A

irflo

w R

ate

(L/s

)

0

100

200

300

400

Setpoint

Measurement



73

Time (h)

0 1 2 3 4 5 6 7 8 9 10 11

Inle

t Pre

ssur

e to

Val

ve (p

si)

20

22

24

26

28

30

32

Inle

t Pre

ssur

e to

Val

ve (k

Pa)

140

150

160

170

180

190

200

210

220

PICCV

Globe Valve


valve for CL 2.3.

Time (h)

0 1 2 3 4 5 6 7 8 9 10 11

Diff

eren

tial P

ress

ure

Acr

oss

Val

ve (p

si)

0

2

4

6

8

10

12

Diff

eren

tial P

ress

ure

Acr

oss

Val

ve (k

Pa)

0

10

20

30

40

50

60

70

80

PICCV

Globe Valve



Time (h)

0 1 2 3 4 5 6 7 8 9 10 11

Accu

mul

ated

Abs

olut

e V

alue

of R

oom

Tem

pera

ture

Err

or (F

-min

)

0

50

100

150

200

250

Accu

mul

ated

Abs

olut

e V

alue

of R

oom

Tem

pera

ture

Err

or (C

-min

)

0

20

40

60

80

100

120

Globe Valve

PICCV



Time (h)

0 1 2 3 4 5 6 7 8 9 10 11

Acc

umul

ated

Act

uato

r Tra

vel

0

50010001500

2000

250030003500

40004500

500055006000

PICCV

Globe Valve


travel for CL 2.3.

Time (h)

0 1 2 3 4 5 6 7 8 9 10 11

Sta

rts a

nd S

tops

0

200

400

600

800

1000

1200

1400

1600

1800

2000

PICCV

Globe Valve



Time (h)

0 1 2 3 4 5 6 7 8 9 10 11

Rev

ersa

ls

0

200

400

600

800

1000

1200

1400

1600

1800

2000

PICCVGlobe Valve



74


• Discharge air temperature control with constant inlet pressure to control valve and variable heating water loop pump speed.

• Belimo PICCV-15-003 installed in South-B test room. • Siemens Powermite MT 599-02036 (Cv = 1.6) installed in South-A test room.

Time (h)

0 1 2 3 4 5 6 7

Con

trol S

igna

l (%

Ope

n)

0

10

20

30

40

50

60

70

80

90

100

Time (h)

0 1 2 3 4 5 6 7

Con

trol S

igna

l (%

Ope

n)

0

10

20

30

40

50

60

70

80

90

100



Time (h)

0 1 2 3 4 5 6 7

Val

ve F

eedb

ack

Sig

nal (

% O

pen)

0

10

20

30

40

50

60

70

80

90

100

Time (h)

0 1 2 3 4 5 6 7

Con

trol S

igna

l (%

Ope

n)

0

10

20

30

40

50

60

70

80

90

100



75

Time (h)

0 1 2 3 4 5 6 7

Hea

ting

Wat

er F

low

Rat

e (L

/s)

0.00

0.05

0.10

0.15

0.20

0.25

0.30

0.35

Hea

ting

Wat

er F

low

Rat

e (G

PM

)

0

1

2

3

4

5

6

Time (h)

0 1 2 3 4 5 6 7

Hea

ting

Wat

er F

low

Rat

e (G

PM

)

0

1

2

3

4

5

6

Hea

ting

Wat

er F

low

Rat

e (L

/s)

0.00

0.05

0.10

0.15

0.20

0.25

0.30

0.35



Time (h)

0 1 2 3 4 5 6 7

Dis

char

ge A

ir Te

mpe

ratu

re (F

)

55

60

65

70

75

80

85

90

Dis

char

ge A

ir Te

mpe

ratu

re (C

)

14

16

18

20

22

24

26

28

30

32

Measurement

Setpoint

Time (h)

0 1 2 3 4 5 6 7

Dis

char

ge A

ir Te

mpe

ratu

re (F

)

55

60

65

70

75

80

85

90

Dis

char

ge A

ir Te

mpe

ratu

re (C

)

14

16

18

20

22

24

26

28

30

32

Measurement

Setpoint


Figure A-37: Discharge air temperature control for CL 2.4.

Time (h)

0 1 2 3 4 5 6 7

Inle

t Pre

ssur

e to

Val

ve (p

si)

20

22

24

26

28

30

32

Inle

t Pre

ssur

e to

Val

ve (k

Pa)

140

150

160

170

180

190

200

210

220

PICCV

Globe Valve


valve for CL 2.4.

Time (h)

0 1 2 3 4 5 6 7

Diff

eren

tial P

ress

ure

Acr

oss

Val

ve (p

si)

0

2

4

6

8

10

12

Diff

eren

tial P

ress

ure

Acr

oss

Valv

e (k

Pa)

0

10

20

30

40

50

60

70

80

Globe Valve

PICCV



76

Time (h)

0 1 2 3 4 5 6 7

Accu

mul

ated

Abs

olut

e V

alue

of D

isch

arge

Tem

pera

ture

Err

or (F

-min

)

0

50

100

150

200

250

Accu

mul

ated

Abs

olut

e V

alue

of D

isch

arge

Tem

pera

ture

Err

or (C

-min

)

0

20

40

60

80

100

120

Globe Valve

PICCV



Time (h)

0 1 2 3 4 5 6 7

Acc

umul

ated

Act

uato

r Tra

vel

0

100

200

300

400

500

600

PICCV

Globe Valve


travel for CL 2.4.

Time (h)

0 1 2 3 4 5 6 7

Sta

rts a

nd S

tops

0

100

200

300

400

500

PICCV

Globe Valve



Time (h)

0 1 2 3 4 5 6 7

Rev

ersa

ls

0

50

100

150

200

PICCV

Globe Valve



77


• Discharge air temperature control with constant inlet pressure to control valve and variable heating water loop pump speed.


Time (h)

0 1 2 3 4 5 6 7

Con

trol S

igna

l (%

Ope

n)

0

10

20

30

40

50

60

70

80

90

100

Time (h)

0 1 2 3 4 5 6 7

Con

trol S

igna

l (%

Ope

n)

0

10

20

30

40

50

60

70

80

90

100



Time (h)

0 1 2 3 4 5 6 7

Val

ve F

eedb

ack

Sig

nal (

% O

pen)

0

10

20

30

40

50

60

70

80

90

100

Time (h)

0 1 2 3 4 5 6 7

Sca

led

Val

ve F

eedb

ack

Sig

nal (

% O

pen)

0

10

20

30

40

50

60

70

80

90

100



78

Time (h)

0 1 2 3 4 5 6 7

Hea

ting

Wat

er F

low

Rat

e (G

PM

)

0

1

2

3

4

5

6

Hea

ting

Wat

er F

low

Rat

e (L

/s)

0.00

0.05

0.10

0.15

0.20

0.25

0.30

0.35

Time (h)

0 1 2 3 4 5 6 7

Hea

ting

Wat

er F

low

Rat

e (G

PM

)

0

1

2

3

4

5

6

Hea

ting

Wat

er F

low

Rat

e (L

/s)

0.00

0.05

0.10

0.15

0.20

0.25

0.30

0.35



Time (h)

0 1 2 3 4 5 6 7

Dis

char

ge A

ir Te

mpe

ratu

re (F

)

55

60

65

70

75

80

85

90

Dis

char

ge A

ir Te

mpe

ratu

re (C

)

14

16

18

20

22

24

26

28

30

32Setpoint

Measurement

Time (h)

0 1 2 3 4 5 6 7

Dis

char

ge A

ir Te

mpe

ratu

re (F

)

55

60

65

70

75

80

85

90

Dis

char

ge A

ir Te

mpe

ratu

re (C

)

14

16

18

20

22

24

26

28

30

32Setpoint

Measurement


Figure A-47: Discharge air temperature control for CL 2.5.

Time (h)

0 1 2 3 4 5 6 7

Inle

t Pre

ssur

e to

Val

ve (p

si)

20

22

24

26

28

30

32

Inle

t Pre

ssur

e to

Val

ve (k

Pa)

140

150

160

170

180

190

200

210

220

Globe Valve

PICCV


valve for CL 2.5.

Time (h)

0 1 2 3 4 5 6 7

Diff

eren

tial P

ress

ure

Acr

oss

Val

ve (p

si)

0

2

4

6

8

10

12

Diff

eren

tial P

ress

ure

Acr

oss

Valv

e (k

Pa)

0

10

20

30

40

50

60

70

80

Globe Valve

PICCV



79

Time (h)

0 1 2 3 4 5 6 7

Accu

mul

ated

Abs

olut

e V

alue

of D

isch

arge

Tem

pera

ture

Err

or (F

-min

)

0

50

100

150

200

250

Accu

mul

ated

Abs

olut

e V

alue

of D

isch

arge

Tem

pera

ture

Err

or (C

-min

)

0

20

40

60

80

100

120Globe Valve

PICCV



Time (h)

0 1 2 3 4 5 6 7

Acc

umul

ated

Act

uato

r Tra

vel

0

100

200

300

400

500

600

PICCV

Globe Valve


travel for CL 2.5.

Time (h)

0 1 2 3 4 5 6 7

Sta

rts a

nd S

tops

0

100

200

300

400

500

PICCV

Globe Valve



Time (h)

0 1 2 3 4 5 6 7

Rev

ersa

ls

0

50

100

150

200

PICCV

Globe Valve



80


• Room air temperature control with variable inlet pressure to control valve and constant heating water loop pump speed.


Time (h)

0 1 2 3 4 5 6 7 8 9 10 11

Con

trol S

igna

l (%

Ope

n)

0

10

20

30

40

50

60

70

80

90

100

Time (h)

0 1 2 3 4 5 6 7 8 9 10 11

Con

trol S

igna

l (%

Ope

n)

0

10

20

30

40

50

60

70

80

90

100



Time (h)

0 1 2 3 4 5 6 7 8 9 10 11

Val

ve F

eedb

ack

Sig

nal (

% O

pen)

0

10

20

30

40

50

60

70

80

90

100

Time (h)

0 1 2 3 4 5 6 7 8 9 10 11

Sca

led

Val

ve F

eedb

ack

Sig

nal (

% O

pen)

0

10

20

30

40

50

60

70

80

90

100



81

Time (h)

0 1 2 3 4 5 6 7 8 9 10 11

Hea

ting

Wat

er F

low

Rat

e (G

PM

)

0

1

2

3

4

5

6

Hea

ting

Wat

er F

low

Rat

e (L

/s)

0.00

0.05

0.10

0.15

0.20

0.25

0.30

0.35

Time (h)

0 1 2 3 4 5 6 7 8 9 10 11

Hea

ting

Wat

er F

low

Rat

e (G

PM

)

0

1

2

3

4

5

6

Hea

ting

Wat

er F

low

Rat

e (L

/s)

0.00

0.05

0.10

0.15

0.20

0.25

0.30

0.35



Time (h)

0 1 2 3 4 5 6 7 8 9 10 11

Roo

m A

ir Te

mpe

ratu

re (F

)

70

71

72

73

74

75

Roo

m A

ir Te

mpe

ratu

re (C

)

21.5

22.0

22.5

23.0

23.5Setpoint

Measurement

Time (h)

0 1 2 3 4 5 6 7 8 9 10 11

Roo

m A

ir Te

mpe

ratu

re (F

)

70

71

72

73

74

75

Roo

m A

ir Te

mpe

ratu

re (C

)

21.5

22.0

22.5

23.0

23.5Setpoint

Measurement



Time (h)

0 1 2 3 4 5 6 7 8 9 10 11

Roo

m A

irflo

w R

ate

(CFM

)

0

100

200

300

400

500

600

700

800

900

1000

Roo

m A

irflo

w R

ate

(L/s

)

0

50

100

150

200

250

300

350

400

450

Setpoint

Measurement

Time (h)

0 1 2 3 4 5 6 7 8 9 10 11

Roo

m A

irflo

w R

ate

(CFM

)

0

100

200

300

400

500

600

700

800

900

1000

Roo

m A

irflo

w R

ate

(L/s

)

0

50

100

150

200

250

300

350

400

450

Measurement

Setpoint



82

Time (h)

0 1 2 3 4 5 6 7 8 9 10 11

Inle

t Pre

ssur

e to

Val

ve (p

si)

20

22

24

26

28

30

32

Inle

t Pre

ssur

e to

Val

ve (k

Pa)

140

150

160

170

180

190

200

210

220

PICCV

Globe Valve


valve for CL 2.6.

Time (h)

0 1 2 3 4 5 6 7 8 9 10 11

Diff

eren

tial P

ress

ure

Acr

oss

Val

ve (p

si)

0

2

4

6

8

10

12

Diff

eren

tial P

ress

ure

Acr

oss

Valv

e (k

Pa)

0

10

20

30

40

50

60

70

80

PICCV

Globe Valve



Time (h)

0 1 2 3 4 5 6 7 8 9 10 11

Acc

umul

ated

Abs

olut

e V

alue

of R

oom

Tem

pera

ture

Err

or (F

-min

)

0

50

100

150

200

250

Acc

umul

ated

Abs

olut

e V

alue

of R

oom

Tem

pera

ture

Err

or (C

-min

)

21.5

22.0

22.5

23.0

23.5

PICCV

Globe Valve



Time (h)

0 1 2 3 4 5 6 7 8 9 10 11

Acc

umul

ated

Act

uato

r Tra

vel

0

500

1000

1500

2000

2500

3000

3500

4000

4500

5000

5500

6000

PICCV

Globe Valve


travel for CL 2.6.

Time (h)

0 1 2 3 4 5 6 7 8 9 10 11

Star

ts a

nd S

tops

0

200

400

600

800

1000

1200

1400

1600

1800

2000

PICCV

Globe Valve



Time (h)

0 1 2 3 4 5 6 7 8 9 10 11

Rev

ersa

ls

0

200

400

600

800

1000

1200

1400

1600

1800

2000

PICCV

Globe Valve



83


• Room air temperature control with variable inlet pressure to control valve and constant heating water loop pump speed.


Time (h)

0 1 2 3 4 5 6 7 8 9 10 11

Con

trol S

igna

l (%

Ope

n)

0

10

20

30

40

50

60

70

80

90

100

Time (h)

0 1 2 3 4 5 6 7 8 9 10 11

Con

trol S

igna

l (%

Ope

n)

0

10

20

30

40

50

60

70

80

90

100



Time (h)

0 1 2 3 4 5 6 7 8 9 10 11

Val

ve F

eedb

ack

Sig

nal (

% O

pen)

0

10

20

30

40

50

60

70

80

90

100

Time (h)

0 1 2 3 4 5 6 7 8 9 10 11

Sca

led

Val

ve F

eedb

ack

Sig

nal (

% O

pen)

0

10

20

30

40

50

60

70

80

90

100



84

Time (h)

0 1 2 3 4 5 6 7 8 9 10 11

Hea

ting

Wat

er F

low

Rat

e (G

PM

)

0

1

2

3

4

5

6

Hea

ting

Wat

er F

low

Rat

e (L

/s)

0.00

0.05

0.10

0.15

0.20

0.25

0.30

0.35

Time (h)

0 1 2 3 4 5 6 7 8 9 10 11

Hea

ting

Wat

er F

low

Rat

e (G

PM

)

0

1

2

3

4

5

6

Hea

ting

Wat

er F

low

Rat

e (L

/s)

0.00

0.05

0.10

0.15

0.20

0.25

0.30

0.35



Time (h)

0 1 2 3 4 5 6 7 8 9 10 11

Roo

m A

ir Te

mpe

ratu

re (F

)

70

71

72

73

74

75R

oom

Air

Tem

pera

ture

(C)

21.5

22.0

22.5

23.0

23.5Setpoint

Measurement

Time (h)

0 1 2 3 4 5 6 7 8 9 10 11

Roo

m A

ir Te

mpe

ratu

re (F

)

70

71

72

73

74

75

Roo

m A

ir Te

mpe

ratu

re (C

)

21.5

22.0

22.5

23.0

23.5Setpoint

Measurement



Time (h)

0 1 2 3 4 5 6 7 8 9 10 11

Roo

m A

irflo

w R

ate

(CFM

)

0

100

200

300

400

500

600

700

800

900

1000

Roo

m A

irflo

w R

ate

(L/s

)

0

50

100

150

200

250

300

350

400

450

Setpoint

Measurement

Time (h)

0 1 2 3 4 5 6 7 8 9 10 11

Roo

m A

irflo

w R

ate

(CFM

)

0

100

200

300

400

500

600

700

800

900

1000

Roo

m A

irflo

w R

ate

(L/s

)

0

50

100

150

200

250

300

350

400

450

Measurement

Setpoint



85

Time (h)

0 1 2 3 4 5 6 7 8 9 10 11

Inle

t Pre

ssur

e to

Val

ve (p

si)

20

22

24

26

28

30

32

Inle

t Pre

ssur

e to

Val

ve (k

Pa)

140

150

160

170

180

190

200

210

220

PICCV

Globe Valve


valve for CL 2.7.

Time (h)

0 1 2 3 4 5 6 7 8 9 10 11

Diff

eren

tial P

ress

ure

Acr

oss

Val

ve (p

si)

0

2

4

6

8

10

12

Diff

eren

tial P

ress

ure

Acr

oss

Valv

e (k

Pa)

0

10

20

30

40

50

60

70

80

PICCV

Globe Valve



Time (h)

0 1 2 3 4 5 6 7 8 9 10 11

Accu

mul

ated

Abs

olut

e V

alue

of R

oom

Tem

pera

ture

Err

or (F

-min

)

0

50

100

150

200

250

Accu

mul

ated

Abs

olut

e V

alue

of R

oom

Tem

pera

ture

Err

or (C

-min

)

0

20

40

60

80

100

120

PICCV

Globe Valve



Time (h)

0 1 2 3 4 5 6 7 8 9 10 11

Acc

umul

ated

Act

uato

r Tra

vel

0

500

1000

1500

2000

2500

3000

3500

4000

4500

5000

5500

6000

PICCV

Globe Valve

Figure A-73: Accumulated actuator travel for CL 2.7.

Time (h)

0 1 2 3 4 5 6 7 8 9 10 11

Star

ts a

nd S

tops

0

200

400

600

800

1000

1200

1400

1600

1800

2000

PICCV

Globe Valve



Time (h)

0 1 2 3 4 5 6 7 8 9 10 11

Rev

ersa

ls

0

200

400

600

800

1000

1200

1400

1600

1800

2000

PICCV

Globe Valve

Figure A-75: Accumulated reversals

for CL 2.7.

86

B. Appendix B: Test Suite 3 Results B.1. Tabulated Results for CL 3.1 Summary of CL 3.1:

• Belimo PICCV installed in System-A test rooms. Loop-A differential pressure setpoint = 9.1 psi. Belimo values highlighted in tables.

• Siemens Powermite MT series globe valves installed in System-B test rooms. Loop-B differential pressure setpoint = 5.2 psi.

Table B-1: Daily reheat energy use, cumulative temperature error, and cumulative change in water flow rate for test rooms East-A and East-B for CL 3.1.

Water-Side Energy Air-Side Energy Cumulative

Temperature Error Cumulative Change in

Water Flow Rate Date Room [BTU] [kJ] [BTU] [kJ]

Energy Balance Error

[%] [F] [C] [GPM] [L/s]

EA -37422 -39480 42176 44495 -11.94 180.4 100.2 12.80 0.81 20050112 EB -50686 -53473 50681 53468 0.01 114.6 63.7 64.63 4.08 EA -36844 -38870 41599 43887 -12.12 248.6 138.1 12.52 0.79

20050113 EB -50918 -53718 49625 52354 2.57 172.5 95.9 57.59 3.63 EA -48592 -51264 52851 55758 -8.40 323.2 179.5 15.12 0.95

20050114 EB -68813 -72597 64808 68373 5.99 257.3 142.9 63.49 4.01 EA -43619 -46018 47815 50445 -9.18 310.3 172.4 14.50 0.91

20050115 EB -62540 -65980 58358 61568 6.92 263.4 146.3 58.51 3.69 EA -34994 -36919 39357 41522 -11.74 313.8 174.3 11.66 0.74

20050116 EB -51893 -54747 49144 51847 5.44 274.3 152.4 54.72 3.45 EA -38667 -40794 42900 45260 -10.38 340.6 189.2 13.47 0.85

20050117 EB -57407 -60564 53461 56401 7.12 298.4 165.8 57.16 3.61 EA -38480 -40596 42966 45329 -11.02 273.0 151.6 11.50 0.73

20050118 EB -54490 -57486 52354 55234 4.00 193.5 107.5 55.13 3.48 EA -32872 -34680 37656 39727 -13.57 182.3 101.3 11.19 0.71

20050119 EB -46976 -49560 45241 47729 3.76 108.5 60.3 55.17 3.48 EA -36355 -38355 41334 43608 -12.82 205.3 114.0 11.18 0.71

20050120 EB -52759 -55661 51297 54118 2.81 135.5 75.3 61.05 3.85

EA -38649 -40775 43184 45559 -11.08 264.2 146.8 12.66 0.80 9-day Averages EB -55164 -58198 52774 55677 4.43 202.0 112.2 58.60 3.70

87

Table B-2: Daily reheat energy use, cumulative temperature error, and cumulative change in water flow rate for test rooms Interior-A and Interior-B for CL 3.1.





[%] [F] [C] [GPM] [L/s]

IA -4347 -4586 7105 7496 -48.17 23.7 13.2 5.52 0.35 20050112 IB -4820 -5085 7065 7454 -37.78 69.4 38.5 6.23 0.39 IA -5082 -5361 7650 8071 -40.34 26.4 14.7 5.50 0.35

20050113 IB -5448 -5748 7610 8028 -33.10 71.3 39.6 6.57 0.41 IA -5298 -5589 7702 8126 -36.99 26.0 14.4 6.17 0.39

20050114 IB -5507 -5810 7525 7938 -30.97 73.0 40.6 6.18 0.39 IA -5405 -5702 7860 8293 -37.02 28.6 15.9 5.69 0.36

20050115 IB -5799 -6118 7866 8298 -30.25 71.6 39.8 6.32 0.40 IA -5076 -5356 7656 8078 -40.53 26.9 15.0 5.95 0.38

20050116 IB -5410 -5708 7419 7827 -31.31 71.2 39.5 6.50 0.41 IA -5280 -5571 7763 8190 -38.07 30.4 16.9 6.10 0.38

20050117 IB -5515 -5819 7525 7939 -30.83 71.5 39.7 6.39 0.40 IA -4591 -4843 7300 7702 -45.57 25.2 14.0 5.29 0.33

20050118 IB -4841 -5108 7067 7455 -37.38 68.4 38.0 6.50 0.41 IA -4926 -5197 7430 7839 -40.52 27.7 15.4 6.38 0.40

20050119 IB -4843 -5109 7087 7476 -37.62 68.7 38.2 6.12 0.39 IA -4632 -4887 7347 7751 -45.33 26.1 14.5 5.02 0.32

20050120 IB -4979 -5253 7266 7666 -37.36 69.9 38.8 6.20 0.39

IA -4960 -5232 7535 7949 -41.22 26.8 14.9 5.74 0.36 9-day Averages IB -5240 -5529 7381 7787 -33.92 70.6 39.2 6.33 0.40

88

Table B-3: Daily reheat energy use, cumulative temperature error, and cumulative change in water flow rate for test rooms South-A and South-B for CL 3.1.





[%] [F] [C] [GPM] [L/s]

SA -48922 -51613 48061 50704 1.78 116.2 64.6 16.05 1.01 20050112 SB -44665 -47122 44872 47340 -0.46 71.8 39.9 53.03 3.35 SA -31760 -33507 29806 31446 6.35 154.3 85.7 13.89 0.88

20050113 SB -29063 -30661 29071 30670 -0.03 89.1 49.5 27.13 1.71 SA -42734 -45084 40961 43214 4.24 308.7 171.5 16.26 1.03

20050114 SB -41095 -43355 40743 42984 0.86 195.6 108.7 25.72 1.62 SA -40230 -42443 37152 39195 7.96 308.5 171.4 15.35 0.97

20050115 SB -39090 -41240 37876 39959 3.16 194.3 107.9 27.53 1.74 SA -32672 -34469 29779 31417 9.26 270.4 150.2 11.77 0.74

20050116 SB -31324 -33047 30679 32367 2.08 185.2 102.9 23.46 1.48 SA -35151 -37084 32160 33929 8.89 308.2 171.2 14.55 0.92

20050117 SB -33217 -35044 32967 34780 0.76 198.6 110.3 23.39 1.48 SA -47785 -50413 46028 48559 3.75 331.0 183.9 15.93 1.01

20050118 SB -46829 -49405 46283 48829 1.17 193.6 107.6 50.59 3.19 SA -33274 -35104 31700 33443 4.85 123.6 68.6 11.60 0.73

20050119 SB -30739 -32430 30857 32555 -0.38 61.6 34.2 34.01 2.15 SA -43290 -45671 42106 44422 2.77 158.8 88.2 13.22 0.83

20050120 SB -39809 -41999 39686 41868 0.31 87.0 48.3 41.42 2.61

SA -38362 -40472 36211 38203 5.77 245.4 136.4 14.29 0.90 9-day Averages SB -37315 -39367 37004 39039 0.84 141.9 78.8 34.03 2.15

89

Table B-4: Daily reheat energy use, cumulative temperature error, and cumulative change in water flow rate for test rooms West-A and West-B for CL 3.1.





[%] [F] [C] [GPM] [L/s]

WA -50328 -53097 49929 52675 0.80 112.8 62.7 19.46 1.23 20050112 WB -44823 -47288 46710 49280 -4.12 83.3 46.3 53.12 3.35 WA -53609 -56557 53395 56331 0.40 246.5 137.0 18.22 1.15 20050113 WB -45316 -47809 46183 48723 -1.89 129.5 72.0 45.54 2.87 WA -59032 -62278 57911 61096 1.92 355.6 197.5 21.04 1.33 20050114 WB -55213 -58250 54582 57584 1.15 302.6 168.1 50.94 3.21 WA -62752 -66203 61290 64661 2.36 308.1 171.2 21.55 1.36 20050115 WB -58179 -61379 57452 60611 1.26 296.8 164.9 47.77 3.01 WA -60198 -63509 58884 62122 2.21 316.3 175.7 14.94 0.94 20050116 WB -54827 -57843 54068 57042 1.39 278.9 154.9 47.80 3.02 WA -58971 -62214 57867 61050 1.89 330.1 183.4 23.11 1.46 20050117 WB -54091 -57066 53936 56902 0.29 299.5 166.4 45.69 2.88 WA -55893 -58967 54877 57896 1.83 223.3 124.0 22.57 1.42 20050118 WB -54875 -57893 55797 58865 -1.67 186.6 103.6 54.34 3.43 WA -41793 -44092 41855 44157 -0.15 163.8 91.0 16.16 1.02 20050119 WB -37248 -39297 38836 40972 -4.17 90.4 50.2 37.80 2.38 WA -46039 -48571 45863 48386 0.38 151.6 84.2 18.21 1.15 20050120 WB -42048 -44361 43181 45556 -2.66 92.7 51.5 43.14 2.72

WA -54291 -57277 53541 56486 1.39 245.3 136.3 19.47 1.23 9-day Averages WB -49625 -52354 50083 52837 -0.92 195.6 108.7 47.35 2.99

90

B.2. Tabulated Results for CL 3.2 Summary of CL 3.2:

• Belimo PICCV installed in System-B test rooms. Loop-B differential pressure setpoint = 8.44 psi. Belimo values highlighted in tables.

• Siemens Powermite MT series globe valves installed in System-A test rooms. Loop-A differential pressure setpoint = 5.36 psi.






[%] [F] [C] [GPM] [L/s]

EA -41552 -43838 46716 49286 -11.70 80.9 44.9 45.03 2.84 20050130 EB -51607 -54445 50775 53567 1.63 146.0 81.1 19.14 1.21 EA -36606 -38619 41808 44108 -13.27 65.0 36.1 37.92 2.39

20050131 EB -46247 -48791 46210 48751 0.08 101.7 56.5 19.37 1.22 EA -35807 -37776 40502 42730 -12.31 58.2 32.3 36.43 2.30

20050201 EB -44526 -46975 44749 47211 -0.50 95.4 53.0 16.73 1.06 EA -32103 -33869 36906 38936 -13.92 58.6 32.6 30.14 1.90

20050202 EB -40876 -43125 41335 43609 -1.12 96.2 53.5 16.77 1.06 EA -19958 -21055 25776 27194 -25.44 79.3 44.1 32.64 2.06

20050203 EB -24863 -26231 25623 27032 -3.01 134.5 74.7 11.02 0.70 EA -16192 -17082 22032 23243 -30.56 67.2 37.3 33.52 2.11

20050204 EB -19769 -20856 20805 21950 -5.11 111.9 62.2 11.28 0.71

EA -30370 -32040 35623 37583 -15.92 68.2 37.9 35.95 2.27 6-day Averages EB -37982 -40071 38250 40353 -0.70 114.3 63.5 15.72 0.99

91






[%] [F] [C] [GPM] [L/s]

IA -6655 -7021 9485 10007 -35.07 69.5 38.6 8.06 0.51 20050130 IB -7838 -8269 9939 10485 -23.64 30.0 16.6 7.83 0.49 IA -5471 -5772 8610 9084 -44.59 64.3 35.7 8.01 0.51

20050131 IB -6724 -7094 8950 9442 -28.40 25.7 14.3 6.83 0.43 IA -5573 -5879 8556 9026 -42.23 64.6 35.9 8.21 0.52

20050201 IB -6417 -6770 8858 9345 -31.96 24.7 13.7 6.38 0.40 IA -5401 -5698 8437 8901 -43.88 64.1 35.6 8.37 0.53

20050202 IB -6306 -6653 8649 9125 -31.34 23.8 13.2 6.27 0.40 IA -5418 -5716 8322 8779 -42.26 61.6 34.2 8.14 0.51

20050203 IB -6057 -6390 8382 8843 -32.21 24.5 13.6 6.11 0.39 IA -5068 -5347 8112 8558 -46.18 61.3 34.1 8.10 0.51

20050204 IB -5576 -5883 8121 8568 -37.17 21.2 11.8 5.82 0.37

IA -5598 -5905 8587 9059 -42.15 64.2 35.7 8.15 0.51 6-day Averages IB -6486 -6843 8817 9301 -30.46 25.0 13.9 6.54 0.41






[%] [F] [C] [GPM] [L/s]

SA -43727 -46132 41974 44283 4.09 56.1 31.2 51.43 3.24 20050130 SB -40899 -43149 40766 43008 0.33 94.6 52.6 17.56 1.11 SA -42001 -44311 40782 43025 2.94 56.6 31.5 50.01 3.16

20050131 SB -39396 -41563 39434 41603 -0.10 78.8 43.8 16.30 1.03 SA -41829 -44130 40693 42931 2.75 51.3 28.5 45.16 2.85

20050201 SB -39206 -41363 39159 41313 0.12 76.1 42.3 18.21 1.15 SA -29428 -31047 28199 29750 4.27 46.3 25.7 30.88 1.95

20050202 SB -26537 -27997 27151 28644 -2.28 81.0 45.0 10.80 0.68 SA -19763 -20850 18451 19466 6.87 58.5 32.5 23.65 1.49

20050203 SB -17387 -18343 17828 18808 -2.50 110.2 61.2 9.35 0.59 SA -15086 -15916 13482 14223 11.23 36.8 20.4 19.64 1.24

20050204 SB -13028 -13745 13611 14360 -4.38 84.9 47.2 8.22 0.52

SA -31972 -33731 30597 32280 4.40 50.9 28.3 36.80 2.32 6-day Averages SB -29409 -31026 29658 31289 -0.84 87.6 48.7 13.41 0.85

92






[%] [F] [C] [GPM] [L/s]

WA -55256 -58295 55438 58487 -0.33 103.5 57.5 68.22 4.30 20050130 WB -46872 -49450 47927 50563 -2.23 188.5 104.7 23.17 1.46 WA -51018 -53824 50948 53750 0.14 81.7 45.4 58.43 3.69

20050131 WB -43695 -46098 44648 47104 -2.16 97.3 54.0 22.78 1.44 WA -48268 -50923 48421 51084 -0.32 71.6 39.8 53.91 3.40

20050201 WB -39512 -41685 42200 44521 -6.58 90.4 50.2 19.58 1.24 WA -33737 -35593 34097 35972 -1.06 60.1 33.4 39.56 2.50

20050202 WB -27135 -28628 30296 31962 -11.01 84.7 47.1 14.69 0.93 WA -33862 -35725 34997 36922 -3.30 85.7 47.6 38.69 2.44

20050203 WB -28591 -30164 30293 31959 -5.78 134.6 74.8 14.24 0.90 WA -27116 -28607 27778 29306 -2.41 67.4 37.4 33.75 2.13

20050204 WB -22375 -23606 24408 25751 -8.69 115.4 64.1 11.50 0.73

WA -41543 -43828 41946 44253 -0.97 78.3 43.5 48.76 3.08 6-day Averages WB -34697 -36605 36629 38643 -5.42 118.5 65.8 17.66 1.11

93

B.3. Tabulated Results for CL 3.3 Summary of CL 3.3:

• Belimo PICCV installed in System-B test rooms. Loop-B differential pressure setpoint = 7.7 psi. Belimo values highlighted in tables.

• Siemens Powermite MT series globe valves installed in System-A test rooms. Loop-A differential pressure setpoint = 7.7 psi.






[%] [F] [C] [GPM] [L/s] EA -18639 -19664 24645 26001 -27.75 53.1 29.5 45.03 2.84

20050205 EB -22626 -23870 23842 25154 -5.24 117.6 65.3 19.14 1.21 EA -27266 -28765 32096 33862 -16.27 71.9 39.9 72.75 4.59

20050206 EB -33303 -35135 34989 36913 -4.94 84.0 46.7 13.02 0.82 EA -34674 -36581 40736 42976 -16.08 64.8 36.0 41.73 2.63

20050207 EB -44255 -46689 44646 47102 -0.88 130.4 72.4 16.31 1.03 EA -38508 -40626 43827 46237 -12.92 124.7 69.3 41.80 2.64

20050208 EB -50988 -53792 50036 52788 1.88 162.6 90.3 19.76 1.25 EA -29772 -31409 35326 37269 -17.06 78.6 43.7 50.33 3.18 4-day

Averages EB -37793 -39872 38378 40489 -1.54 123.6 68.7 17.06 1.08






[%] [F] [C] [GPM] [L/s] IA -5127 -5409 8187 8638 -45.97 56.3 31.3 8.06 0.51

20050205 IB -5734 -6049 8305 8761 -36.63 21.8 12.1 7.83 0.49 IA -4554 -4805 7838 8269 -53.00 56.4 31.4 9.13 0.58

20050206 IB -5109 -5390 7876 8309 -42.61 19.8 11.0 5.37 0.34 IA -5447 -5747 8538 9007 -44.20 58.9 32.7 9.90 0.62

20050207 IB -6490 -6847 8804 9288 -30.26 25.7 14.3 6.45 0.41 IA -5263 -5552 8221 8673 -43.88 59.2 32.9 9.72 0.61

20050208 IB -6084 -6418 8517 8985 -33.33 23.8 13.2 5.81 0.37 IA -5098 -5378 8196 8647 -46.61 57.7 32.0 9.20 0.58 4-day

Averages IB -5854 -6176 8375 8836 -35.44 22.8 12.6 6.36 0.40

94






[%] [F] [C] [GPM] [L/s] SA -17985 -18974 17769 18746 1.21 40.9 22.7 51.43 3.24

20050205 SB -16900 -17830 17588 18555 -3.99 110.0 61.1 17.56 1.11 SA -31436 -33165 30691 32379 2.40 54.9 30.5 74.01 4.67

20050206 SB -30830 -32526 31234 32952 -1.30 89.3 49.6 12.76 0.80 SA -37257 -39306 37040 39077 0.58 64.6 35.9 41.57 2.62

20050207 SB -34228 -36110 35037 36964 -2.34 136.9 76.1 13.55 0.85 SA -44276 -46711 44199 46630 0.17 124.1 69.0 40.32 2.54

20050208 SB -41065 -43323 41362 43637 -0.72 215.7 119.8 15.16 0.96 SA -32738 -34539 32425 34208 0.96 71.1 39.5 51.83 3.27 4-day

Averages SB -30756 -32447 31305 33027 -1.77 138.0 76.7 14.76 0.93






[%] [F] [C] [GPM] [L/s] WA -26473 -27930 27677 29199 -4.44 58.9 32.7 68.22 4.30

20050205 WB -22695 -23943 24598 25951 -8.05 133.8 74.3 23.17 1.46 WA -37739 -39814 37959 40047 -0.58 48.9 27.2 73.73 4.65

20050206 WB -30028 -31679 32513 34302 -7.95 104.2 57.9 12.16 0.77 WA -46944 -49525 48120 50767 -2.48 106.3 59.1 54.13 3.42

20050207 WB -39528 -41702 40538 42767 -2.52 168.3 93.5 16.45 1.04 WA -56773 -59896 57585 60752 -1.42 174.3 96.9 63.92 4.03

20050208 WB -48463 -51128 49387 52103 -1.89 178.6 99.2 22.18 1.40 WA -41982 -44291 42835 45191 -2.01 97.1 54.0 65.00 4.10 4-day

Averages WB -35178 -37113 36759 38781 -4.39 146.2 81.2 18.49 1.17

95

C. Appendix C: Test Suite 5 Results C.1. Plotted Results for CL 5.1 Summary of CL 5.1:

• Belimo PICCV installed in chilled water return of AHU-A cooling coil. • Siemens Powermite MT series globe valve installed in chilled water return of AHU-B

cooling coil.

Time (h)

0 1 2 3 4 5 6 7

Con

trol S

igna

l (%

Ope

n)

0

10

20

30

40

50

60

70

80

90

100

Time (h)

0 1 2 3 4 5 6 7

Con

trol S

igna

l (%

Ope

n)

0

10

20

30

40

50

60

70

80

90

100


Figure C-1: Valve control signal for CL 5.1.

Time (h)

0 1 2 3 4 5 6 7

Val

ve F

eedb

ack

Sig

nal (

% O

pen)

0

10

20

30

40

50

60

70

80

90

100

Time (h)

0 1 2 3 4 5 6 7

Sca

led

Val

ve F

eedb

ack

Sig

nal (

% O

pen)

0

10

20

30

40

50

60

70

80

90

100


Figure C-2: Valve position feedback signal for CL 5.1.

96

Time (h)

0 1 2 3 4 5 6 7

Chi

lled

Wat

er F

low

Rat

e (G

PM)

0

1

2

3

4

5

6

7

89

10

11

12

Chi

lled

Wat

er F

low

Rat

e (L

/s)

0.0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

Time (h)

0 1 2 3 4 5 6 7

Chi

lled

Wat

er F

low

Rat

e (G

PM)

0

1

2

3

4

5

6

7

89

10

11

12

Chi

lled

Wat

er F

low

Rat

e (L

/s)

0.0

0.1

0.2

0.3

0.4

0.5

0.6

0.7


Figure C-3: Chilled water flow rate for CL 5.1.

Time (h)

0 1 2 3 4 5 6 7

Sup

ply

Air T

empe

ratu

re (F

)

50

55

60

65

70

75

Sup

ply

Air T

empe

ratu

re (C

)

10

12

14

16

18

20

22

Measurement

Setpoint

Time (h)

0 1 2 3 4 5 6 7

Sup

ply

Air T

empe

ratu

re (F

)

50

55

60

65

70

75

Sup

ply

Air T

empe

ratu

re (C

)

10

12

14

16

18

20

22

MeasurementSetpoint


Figure C-4: Supply air temperature control for CL 5.1.

Time (h)

0 1 2 3 4 5 6 7

Sum

of R

oom

Airf

low

Rat

es (C

FM)

2350

2360

2370

2380

2390

2400

2410

2420

2430

2440

2450

Sum

of R

oom

Airf

low

Rat

es (L

/s)

1110

1115

1120

1125

1130

1135

1140

1145

1150

1155

Time (h)

0 1 2 3 4 5 6 7

Sum

of R

oom

Airf

low

Rat

es (C

FM)

2350

2360

2370

2380

2390

2400

2410

2420

2430

2440

2450

Sum

of R

oom

Airf

low

Rat

es (L

/s)

1110

1115

1120

1125

1130

1135

1140

1145

1150

1155


Figure C-5: Sum of room airflow rates for CL 5.1.

97

Time (h)

0 1 2 3 4 5 6 7

Tem

pera

ture

Ris

e A

cros

s C

oolin

g C

oil (

F)

10

12

14

16

18

20

22

24

26

28

30

Tem

pera

ture

Ris

e Ac

ross

Coo

ling

Coi

l (C

)

6

7

8

9

10

11

12

13

14

15

16

Time (h)

0 1 2 3 4 5 6 7

Tem

pera

ture

Ris

e A

cros

s C

oolin

g C

oil (

F)

10

12

14

16

18

20

22

24

26

28

30

Tem

pera

ture

Ris

e Ac

ross

Coo

ling

Coi

l (C

)

6

7

8

9

10

11

12

13

14

15

16


Figure C-6: Temperature rise across cooling coil for CL 5.1.

Time (h)

0 1 2 3 4 5 6 7

Inle

t Pre

ssur

e to

Val

ve (p

si)

15

20

25

30

35

40

Inle

t Pre

ssur

e to

Val

ve (k

Pa)

120

140

160

180

200

220

240

260

PICCV

Globe Valve

Figure C-7: Inlet pressure to

valve for CL 5.1.

Time (h)

0 1 2 3 4 5 6 7

Diff

eren

tial P

ress

ure

Acr

oss

Val

ve (p

si)

25

30

35

40

45

50

55

Diff

eren

tial P

ress

ure

Acr

oss

Valv

e (k

Pa)

180

200

220

240

260

280

300

320

340

360

Figure C-8: Differential pressure


Time (h)

0 1 2 3 4 5 6 7

Accu

mul

ated

Abs

olut

e Va

lue

of S

uppl

y A

ir Te

mpe

ratu

re E

rror

(F-m

in)

0

50

100

150

200

250

Accu

mul

ated

Abs

olut

e Va

lue

of S

uppl

y A

ir Te

mpe

ratu

re E

rror

(C-m

in)

0

20

40

60

80

100

120

Globe Valve

PICCV

Figure C-9: Accumulated supply air


Time (h)

0 1 2 3 4 5 6 7

Acc

umul

ated

Act

uato

r Tra

vel

0

20

40

60

80

100

120

140

160

180

200

PICCV

Globe Valve

Figure C-10: Accumulated actuator

travel for CL 5.1.

98

Time (h)

0 1 2 3 4 5 6 7

Sta

rts a

nd S

tops

0

25

50

75

100

125

150

175

200

225

250

PICCV

Globe Valve

Figure C-11: Accumulated starts


Time (h)

0 1 2 3 4 5 6 7

Rev

ersa

ls

0

10

20

30

40

50

60

70

80

90

100

PICCV

Globe Valve

Figure C-12: Accumulated reversals

for CL 5.1.

Time (h)

0 1 2 3 4 5 6 7

Cum

ulat

ive

Cha

nge

in F

low

Rat

e (G

PM

)

0

50

100

150

200

250

300

350

400

450

500C

umul

ativ

e C

hang

e in

Flo

w R

ate

(L/s

)

0

5

10

15

20

25

30

PICCV

Globe Valve

Figure C-13: Cumulative change in flow rate for CL 5.1.

Time (h)

0 1 2 3 4 5 6 7

Sec

onda

ry C

hille

d W

ater

Pum

p P

ower

(W)

250

260

270

280

290

300

310

320

330

340

Globe Valve

PICCV

Figure C-14: Secondary pump power

for CL 5.1.

99

C.2. Plotted Results for CL 5.2 Summary of CL 5.2:

• Belimo PICCV installed in chilled water return of AHU-B cooling coil. • Siemens Powermite MT series globe valve installed in chilled water return of AHU-A

cooling coil.

Time (h)

0 1 2 3 4 5 6 7

Con

trol S

igna

l (%

Ope

n)

0

10

20

30

40

50

60

70

80

90

100

Time (h)

0 1 2 3 4 5 6 7C

ontro

l Sig

nal (

% O

pen)

0

10

20

30

40

50

60

70

80

90

100

(a) Siemens (b) Belimo

Figure C-15: Valve control signal for CL 5.2.

Time (h)

0 1 2 3 4 5 6 7

Sca

led

Val

ve F

eedb

ack

Sig

nal (

% O

pen)

0

10

20

30

40

50

60

70

80

90

100

Time (h)

0 1 2 3 4 5 6 7

Val

ve F

eedb

ack

Sig

nal (

% O

pen)

0

10

20

30

40

50

60

70

80

90

100


Figure C-16: Valve position feedback signal for CL 5.2.

100

Time (h)

0 1 2 3 4 5 6 7

Chi

lled

Wat

er F

low

Rat

e (G

PM)

0

1

2

3

4

5

6

7

89

10

11

12

Chi

lled

Wat

er F

low

Rat

e (L

/s)

0.0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

Time (h)

0 1 2 3 4 5 6 7

Chi

lled

Wat

er F

low

Rat

e (G

PM)

0

1

2

3

4

5

6

7

89

10

11

12

Chi

lled

Wat

er F

low

Rat

e (L

/s)

0.0

0.1

0.2

0.3

0.4

0.5

0.6

0.7


Figure C-17: Chilled water flow rate for CL 5.2.

Time (h)

0 1 2 3 4 5 6 7

Sup

ply

Air T

empe

ratu

re (F

)

50

55

60

65

70

75

Sup

ply

Air T

empe

ratu

re (C

)

10

12

14

16

18

20

22

Measurement

Setpoint

Time (h)

0 1 2 3 4 5 6 7

Sup

ply

Air T

empe

ratu

re (F

)

50

55

60

65

70

75

Sup

ply

Air T

empe

ratu

re (C

)

10

12

14

16

18

20

22

MeasurementSetpoint


Figure C-18: Supply air temperature control for CL 5.2.

Time (h)

0 1 2 3 4 5 6 7

Sum

of R

oom

Airf

low

Rat

es (C

FM)

2350

2360

2370

2380

2390

2400

2410

2420

2430

2440

2450

Sum

of R

oom

Airf

low

Rat

es (L

/s)

1110

1115

1120

1125

1130

1135

1140

1145

1150

1155

Time (h)

0 1 2 3 4 5 6 7

Sum

of R

oom

Airf

low

Rat

es (C

FM)

2350

2360

2370

2380

2390

2400

2410

2420

2430

2440

2450

Sum

of R

oom

Airf

low

Rat

es (L

/s)

1110

1115

1120

1125

1130

1135

1140

1145

1150

1155


Figure C-19: Sum of room airflow rates for CL 5.2.

101

Time (h)

0 1 2 3 4 5 6 7

Tem

pera

ture

Ris

e A

cros

s C

oolin

g C

oil (

F)

10

12

14

16

18

20

22

24

26

28

30

Tem

pera

ture

Ris

e Ac

ross

Coo

ling

Coi

l (C

)

6

7

8

9

10

11

12

13

14

15

16

Time (h)

0 1 2 3 4 5 6 7

Tem

pera

ture

Ris

e A

cros

s C

oolin

g C

oil (

F)

10

12

14

16

18

20

22

24

26

28

30

Tem

pera

ture

Ris

e Ac

ross

Coo

ling

Coi

l (C

)

6

7

8

9

10

11

12

13

14

15

16


Figure C-20: Temperature rise across cooling coil for CL 5.2.

Time (h)

0 1 2 3 4 5 6 7

Inle

t Pre

ssur

e to

Val

ve (p

si)

15

20

25

30

35

40

Inle

t Pre

ssur

e to

Val

ve (k

Pa)

120

140

160

180

200

220

240

260

PICCV

Globe Valve

Figure C-21: Inlet pressure to

valve for CL 5.2.

Time (h)

0 1 2 3 4 5 6 7

Diff

eren

tial P

ress

ure

Acr

oss

Val

ve (p

si)

25

30

35

40

45

50

55

Diff

eren

tial P

ress

ure

Acr

oss

Valv

e (k

Pa)

180

200

220

240

260

280

300

320

340

360

Figure C-22: Differential pressure


Time (h)

0 1 2 3 4 5 6 7

Accu

mul

ated

Abs

olut

e Va

lue

of S

uppl

y A

ir Te

mpe

ratu

re E

rror

(F-m

in)

0

50

100

150

200

250

Accu

mul

ated

Abs

olut

e Va

lue

of S

uppl

y A

ir Te

mpe

ratu

re E

rror

(C-m

in)

0

20

40

60

80

100

120

Globe Valve

PICCV

Figure C-23: Accumulated supply air


Time (h)

0 1 2 3 4 5 6 7

Accu

mul

ated

Act

uato

r Tra

vel

0

20

40

60

80

100

120

140

160

180

200

PICCV

Globe Valve

Figure C-24: Accumulated actuator

travel for CL 5.2.

102

Time (h)

0 1 2 3 4 5 6 7

Sta

rts a

nd S

tops

0

25

50

75

100

125

150

175

200

225

250

PICCV

Globe Valve

Figure C-25: Accumulated starts


Time (h)

0 1 2 3 4 5 6 7

Rev

ersa

ls

0

10

20

30

40

50

60

70

80

90

100

PICCV

Globe Valve

Figure C-26: Accumulated reversals

for CL 5.2.

Time (h)

0 1 2 3 4 5 6 7

Cum

ulat

ive

Cha

nge

in F

low

Rat

e (G

PM

)

0

50

100

150

200

250

300

350

400

450

500

Cum

ulat

ive

Cha

nge

in F

low

Rat

e (L

/s)

0

5

10

15

20

25

30

PICCV

Globe Valve

Figure C-27: Cumulative change in

flow rate for CL 5.2.

Time (h)

0 1 2 3 4 5 6 7

Seco

ndar

y C

hille

d W

ater

Pum

p Po

wer

(W)

250

260

270

280

290

300

310

320

330

340

Globe Valve

PICCV

Figure C-28: Secondary pump power

for CL 5.2.

testing of belimo pressure independent...

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