retro commissioning report - texas a&m university...the retro commissioning (rc) process...

RETRO COMMISSIONING REPORT

For The

Veterinary Medicine Large Animal Clinic (BLDG 1194)

SUBMITTED TO:

Office of Energy Management

Physical Plant Department

Texas A&M University

PREPARED BY:

Energy Systems Laboratory

Texas A&M University

FEBRUARY 15, 2008

EXECUTIVE SUMMARY

The building assessed in this report is the Veterinary Medicine Large Animal Clinic (Building 1194). It is a two-story building and is located on the main campus at Texas A&M University. The total area is about 140,865 square feet, which consists primarily of equine medical and surgery wards, equine exam rooms, food animal complex, intensive care unit, pharmacy, radiology section, veterinary classrooms and offices. The HVAC system consists of seven single duct variable air volume units four constant air volume outside air units and ten fan coil units. A Siemens controls system operates the equipment.

The Retro Commissioning (RC) activities began on July 23, 2007. A thorough investigation and evaluation of current building conditions and operation, including field measurements, sensor verification and control review, have been performed. The causes of a number of comfort and energy efficiency problems in the building were identified. The major RC measures recommended include:

1. Reactivate and optimize heat recovery system for AHUs HW1-4.

2. Optimize damper and return fan controls for AHUs HP1-7.

3. Optimize discharge air temperature setpoint for AHUs HP1-7.

4. Improve static pressure set point scheduling for AHUs HP1-5 and 7.

5. Optimize the minimum air flow set points for VAV boxes.

6. Optimize CHW system control.

7. Optimize HHW system control.

8. Optimize RHW system control

9. Optimize FCU control.

10. Optimize steam boiler control.

11. Optimize the discharge air temperature control for AHU HW4.

12. Optimize preheat temperature setpoint for AHUs HP1-6.

13. Program the AHU valve and damper command values to reflect actual measured spring ranges.

At the time of submittal of this report, 11 out of 13 RC measures have been implemented. However, because post RC data are not accumulated sufficiently to perform the savings analysis, this report does not contain measured savings results and will be updated in the future. Based on the understanding of the current system situation and engineering calculation, it is estimated that implementation of the recommended RC measures would result in an approximate $75,000 annual energy cost avoidance indicating large energy savings potentials. The value was based on a rate of

$9.602/MMBtu for chilled water, $13.099/MMBtu for hot water, and $0.092/kWh for electricity.

During the RC process, a list of maintenance issues were accumulated and submitted to the routine weekly meetings with Area Maintenance (AM) and Office of Energy Management (OEM). At time of the submittal of this report, these items have been substantially completed. The list of maintenance items can be found in Table 17.

Main comfort issues in this building were temperature fluctuation and high humidity in some areas of this building. It is anticipated that these issues were resolved by implementing the RC measures listed above and maintenance issues that have been resolved during the process.

ACKNOWLEDGEMENTS

The Retro Commissioning (RC) process detailed in this report is a collaborative effort among the building proctor, the Office of Energy Management (OEM), Area Maintenance (AM), and the Energy Systems Laboratory (ESL) at Texas A&M University. Many persons from each entity were responsible for the work done in the building, from the field and comfort measurements and RC measures determination, to the maintenance and controls items implemented. This document is designed to serve as a deliverable from ESL to OEM, and primarily details the RC activities and measures.

For information concerning the Office of Energy Management, please contact Homer L. Bruner, Jr. at (979)862-2794. The lead RC investigator for this building was Hui Li. For additional information regarding the information in this report or the overall Continuous Commissioning® program at the Energy Systems Laboratory, please contact Song Deng at (979)862-1234.

TABLE OF CONTENTS

EXECUTIVE SUMMARY .................................................................................................. i

ACKNOWLEDGEMENTS ............................................................................................... iii

TABLE OF CONTENTS ................................................................................................... iv

LIST OF FIGURES ............................................................................................................. v

LIST OF TABLES ............................................................................................................. vi

BACKGROUND ................................................................................................................. 1

SITE DESCRIPTION ......................................................................................................... 1

General Facility Description ........................................................................................... 1

General HVAC System Description ............................................................................... 2

Energy and Comfort Baselines ........................................................................................ 2

RETRO COMMISSIONING MEASURES ........................................................................ 8

Retro Commissioning Measures ..................................................................................... 8

Retro Commissioning Results ....................................................................................... 22

MAINTENANCE ISSUES ............................................................................................... 23

Observed Maintenance Related Issues .......................................................................... 23

CONCLUSIONS ............................................................................................................... 25

APPENDIX A – HVAC As-Built Information ................................................................. 27

APPENDIX B – Field Measurement Records .................................................................. 28

APPENDIX C – Pre-RC Control Settings ........................................................................ 43

LIST OF FIGURES

Figure 1. Veterinary Medicine Large Animal Clinic. ....................................................... 1

Figure 2. Building location. ............................................................................................... 1

Figure 3. Time series for Veterinary Medicine Large Animal Hospital (#1194). Period covered is the baseline model time frame: 8/1/2006 to 7/31/2007. ........................... 3

Figure 4. Electricity vs. outside air dry-bulb temperature of the baseline during weekdays for Veterinary Medicine Large Animal Hospital (#1194). Baseline Period: 8/1/2006 to 7/31/2007. ................................................................................... 4

Figure 5. Electricity vs. outside air dry-bulb temperature of the baseline during weekends for Veterinary Medicine Large Animal Hospital (#1194). Baseline Period: 8/1/2006 to 7/31/2007. ................................................................................... 4

Figure 6. Chilled water vs. outside air dry-bulb temperature of the baseline for Veterinary Medicine Large Animal Hospital (#1194). Baseline Period: 8/1/2006 to 7/31/2007. ................................................................................................................... 5

Figure 7. Hot water vs. outside air dry-bulb temperature of the baseline for Veterinary Medicine Large Animal Hospital (#1194). Baseline Period: 10/25/2006 to 7/31/2007. ................................................................................................................... 5

Figure 8. Trended temperature for Front Reception, ICU and Pharmacy zone ................. 7

Figure 9. Trended humidity for Front Reception, ICU and Pharmacy zone ...................... 7

LIST OF TABLES

Table 1. Summary of annual energy use based on the baseline period. ............................. 6

Table 2. Recommended RC measures with priority level and implementation status. ...... 8

Table 3. Pre-RC dampers and return fan control sequence for AHUs HP 1-7 ................ 10

Table 4. Proposed dampers and return fan control sequence for AHUs HP 1-7 .............. 11

Table 5. Discharge air temperature set point schedule for AHUs HP 1-7 ....................... 12

Table 6. Pre-RC Static pressure set point schedule for four AHUs. ................................ 13

Table 7. Proposed static pressure set point control for AHUs HP1-5, 7 .......................... 14

Table 8. Minimum air flow set points for non-hospital function areas ............................ 14

Table 9. Pre-RC CHW secondary loop differential pressure set point control. ............... 15

Table 10. Pre-RC CHW secondary loop differential pressure set point control. ............. 16

Table 11. Pre-RC HHW secondary loop differential pressure set point control. ............. 17

Table 12. Proposed HHW secondary loop differential pressure set point. ...................... 17

Table 13. Steam pressure requirement for steam equipment. .......................................... 20

Table 14. Pre-RC preheat and discharge air temperature set points for AHU HW4 ....... 20

Table 15. Pre-RC preheat set points for AHUs HP 1-6 ................................................... 21

Table 16. Programmed and measured AHU valve spring ranges .................................... 21

Table 17. Observed maintenance related issues. .............................................................. 23

Table A - 1. Building pumping information ................................................................... 27

Table A - 2. HVAC system AHU airflow design information. ....................................... 27

Table C - 1. Pre-RC CHW secondary loop differential pressure set point control. ........ 43

Table C - 2. Pre-RC HHW secondary loop differential pressure set point control. ........ 43

Table C - 3. Pre-RC dampers and return fan control sequence for AHUs HP 1-7.......... 43

Table C - 4. Discharge air temperature set point schedule for AHUs HP 1-7 ................ 44

Table C - 5. Pre-RC Static pressure set point schedule for four AHUs. ......................... 44

Table C - 6. Pre-RC preheat set points for AHUs HP 1-6 .............................................. 45

1

BACKGROUND

Retro Commissioning is an ongoing process to resolve operating problems, improve comfort, optimize energy use, and identify retrofits for existing commercial and institutional buildings and central plant facilities. The Energy Systems Laboratory has been under contract with the Physical Plant at Texas A&M University since 1997 to systematically commission the campus buildings as requested. During the time period since this began, more than 70 buildings have been commissioned, resulting in energy savings to Texas A&M University of millions of dollars. For the year 2007, 25 buildings (totaling 2.5 million square feet) have been identified to be commissioned, including the Veterinary Medicine Large Animal Clinic. This building was identified as a prime candidate for Retro Commissioning due to its high energy cost per square foot and comfort problems. Commissioning began on July 23, 2007.

SITE DESCRIPTION

General Facility Description

Figure 1. Veterinary Medicine Large Animal Clinic. Figure 2. Building location.

The Veterinary Medicine Large Animal Clinic, pictured above in Figure 1, was originally constructed in 1993 and is located on the main campus of Texas A&M University (see Figure 2 above). It consists primarily of equine medical and surgery wards, equine exam rooms, food animal complex, intensive care unit, pharmacy, radiology section, veterinary classrooms and offices. The building has a main floor and a second office floor. The total area is about 140,865 square feet. All areas are open 24 hours a day 7 days a week.

2

General HVAC System Description

Mechanical

The chilled water system in the building utilizes two identical pumps, each 50 hp and 1,320 gpm, with VFDs under EMCS control. The building piping system is variable flow with two-way piping. The heating water system in the building utilizes two identical pumps, each 25 hp and 450 gpm, under EMCS control. The piping system is variable flow with a combination of two-way and three-way piping. A summary of the building pumping information is shown in Table A-1 in the Appendix.

The HVAC system in the building consists of seven single duct variable air volume units (AHU HP system), four constant air volume outside air units (AHU HW system) and ten fan coil units (FCU system). The total design supply flow is 137,700 cfm for the AHU HP system while 55,450 cfm for the AHU HW system. All AHUs except the HP7 have glycol heat recovery systems. Tables A-2 and A-3 in the Appendix provide an overview of the air handling units and exhaust fans comprising the building HVAC system, with their design information.

Controls

The control system for the building is DDC controlled with pneumatic actuators and is powered by Siemens Apogee.

The pre-RC operation of CHW/HHW pumps staged the pumps on according to building demand. The pumps and control valves were controlled to maintain the secondary loop differential pressures set points. These set points were reset based on the outside air dry-bulb temperature.

All HVAC equipment runs 24 hours a day, seven days a week. The heat recovery systems were enabled based on the outside air dry bulb temperature or the differential temperature of outside air dry bulb temperature and return air temperature. Each HP system had a temperature economizer control. The supply fan speeds for these units were modulated to maintain the end static pressure set points and return fan speeds were modulated to maintain the return air flow set points. The control valves for HP cooling/heating coils were controlled to maintain the discharge air temperature set points which were reset based on outside air dry bulb temperature.

Energy and Comfort Baselines

The baseline period was from August 1st, 2006 to July 31st, 2007. Figure 4 shows the time series plots for the consumptions of Electricity, CHW and HHW, and the outside air dry-bulb temperature by using daily data. Figures 5-7 then show the consumption as it relates to average daily outdoor dry bulb temperature during the baseline data. HHW consumption has near 0 values for data between 8/15/2006 to 9/18/2006.

3

Veterinary Medicine Large Animal Hospital TAMU / BLDG #: 1194

0

1,000

2,000

3,000

4,000

5,000

6,000

7,000

8,000

9,000

07/02/2006 08/21/2006 10/10/2006 11/29/2006 01/18/2007 03/09/2007 04/28/2007 06/17/2007 08/06/2007 09/25/2007

Wbe

le (k

Wh/

day)

0

10

20

30

40

50

60

70

80

07/02/2006 08/21/2006 10/10/2006 11/29/2006 01/18/2007 03/09/2007 04/28/2007 06/17/2007 08/06/2007 09/25/2007

Wbc

ool (

MM

Btu

/day

)

0.0

10.0

20.0

30.0

40.0

50.0

60.0

07/02/2006 08/21/2006 10/10/2006 11/29/2006 01/18/2007 03/09/2007 04/28/2007 06/17/2007 08/06/2007 09/25/2007

Wbh

eat (

MM

Btu

/day

)

0

20

40

60

80

100

120

07/02/2006 08/21/2006 10/10/2006 11/29/2006 01/18/2007 03/09/2007 04/28/2007 06/17/2007 08/06/2007 09/25/2007

Ave

rage

Tdb

(°F)

Figure 3. Time series for Veterinary Medicine Large Animal Hospital (#1194). Period covered is the baseline model time frame: 8/1/2006 to 7/31/2007.

4

Veterinary Medicine Large Animal Hospital TAMU# 1194Baseline: 8/1/2006 - 7/31/2007

0

1000

2000

3000

4000

5000

6000

7000

8000

9000

10000

0 20 40 60 80 100Tdb [°F]

Wee

kday

s El

ectri

city

Con

sum

ptio

n [k

Wh/

day]

Figure 4. Electricity vs. outside air dry-bulb temperature of the baseline during weekdays for Veterinary Medicine Large Animal Hospital (#1194). Baseline Period: 8/1/2006 to 7/31/2007.


0

1000

2000

3000

4000

5000

6000

7000

8000

9000

10000

0 20 40 60 80 100Tdb [°F]

Wee

kend

s El

ectri

city

Con

sum

ptio

n [k

Wh/

day]

Figure 5. Electricity vs. outside air dry-bulb temperature of the baseline during weekends for Veterinary Medicine Large Animal Hospital (#1194). Baseline Period: 8/1/2006 to 7/31/2007.

5


0

10

20

30

40

50

60

70

80

90

100

0 20 40 60 80 100Tdb [°F]

Chi

lled

Wat

er C

onsu

mpt

ion

[MM

Btu

/day

]

Figure 6. Chilled water vs. outside air dry-bulb temperature of the baseline for Veterinary Medicine Large Animal Hospital (#1194). Baseline Period: 8/1/2006 to 7/31/2007.


0

10

20

30

40

50

60

0 20 40 60 80 100Tdb [°F]

Hot

Wat

er C

onsu

mpt

ion

[MM

Btu

/day

]

Figure 7. Hot water vs. outside air dry-bulb temperature of the baseline for Veterinary Medicine Large Animal Hospital (#1194). Baseline Period: 10/25/2006 to 7/31/2007.

6

The annual energy consumption for the building during the baseline period is summarized in Table 1.

Table 1. Summary of annual energy use based on the baseline period.

Annual Use

Unit Cost

Energy Cost

Baseline Period

ELE 17.6009 (kWh/ft2/yr) 0.092 ($/kWh) 1.6193 ($/ft2/yr) 8/1/2006 to 7/31/2007

CHW 0.0869 (mmBtu/ft2/yr) 9.602 ($/mmBtu) 0.8345 ($/ft2/yr) 8/1/2006 to 7/31/2007

HHW 0.0344 (mmBtu/ft2/yr) 13.099 ($/mmBtu) 0.4507 ($/ft2/yr) 10/25/2006 to 7/31/2007

The baseline Energy Usage Index (EUI) was 181.4 mBtu/ft2-year. The baseline Energy Cost Index (ECI) was $2.9045/ft2-year.

Several comfort complaints in the building were discussed during the kick-off meeting. The building proctor indicated that temperature fluctuations and high humidity complaints were particularly prevalent in the building. To further investigate these complaints, data loggers were left in the building over a period of time during the investigation. The temperature and humidity trended represent three rooms served by different AHUs, as well as outside air temperature and humidity. According to the trended data during the specific period, temperature fluctuations are not apparent except that the temperature of the front reception zone fluctuates largely, as shown in Figure 8 and Figure 9. The humidity of the rooms also stays at an acceptable level except that the humidity of the ICU zone accidentally increases due to the spray water. Since the trended data is just over several days and cannot reflect the conditions throughout the entire year, the potential causes and solutions for temperature fluctuations and high humidity complaints are still discussed in the following sections of this report.

7

60

65

70

75

80

85

90

95

100

8/6/07 0:00 8/6/07 12:00 8/7/07 0:00 8/7/07 12:00 8/8/07 0:00 8/8/07 12:00 8/9/07 0:00

Tem

pera

ture

, F

Front Reception (AHU HP1) Pharm 103 (AHU HP6)ICU 116 (AHU HP3) Outside Air DB Temperature

Figure 8. Trended temperature for Front Reception, ICU and Pharmacy zone

30

40

50

60

70

80

90

100

110

8/6/07 0:00 8/6/07 12:00 8/7/07 0:00 8/7/07 12:00 8/8/07 0:00 8/8/07 12:00 8/9/07 0:00

Rel

ativ

e H

umid

ity, %

Front Reception (AHU HP1) Pharm 103 (AHU HP6)ICU 116 (AHU HP3) Outside Air Relative Humidity

Figure 9. Trended humidity for Front Reception, ICU and Pharmacy zone

8

RETRO COMMISSIONING MEASURES

The Retro Commissioning process involved a thorough evaluation of current building conditions and operation, including field measurements, remote monitoring, and control review. From the investigation performed, the causes of a number of comfort and energy efficiency problems in the building were identified. RC measures have been implemented to aid in allowing this building to operate more efficiently and to provide better comfort. Additionally, maintenance issues that were noted during the RC process have been documented. The sections that follow describe the conditions found in the building at the time of RC, the RC measures recommended for improved building performance, and the results achieved thus far from those measures that have been implemented.

Retro Commissioning Measures

A total of thirteen RC measures have been identified through the RC process. These RC measures are summarized in Table 2, with their priorities and implementation status as of the report submittal date. As can be seen in the table, eleven of the recommended RC measures have been implemented as of the submittal of this report. Detailed findings and explanations of the measures are provided following the table.

Table 2. Recommended RC measures with priority level and implementation status.

No# Brief RC Measure Description Priority Implementation Status

RC1 Reactivate and optimize heat recovery system for AHUs HW1-4 High Completed

RC2 Optimize damper and return fan control for AHUs HP1-7 High Completed

RC3 Optimize discharge air temperature setpoint for AHUs HP1-7 High Completed

RC4 Improve static pressure set point scheduling for AHUs HP1-5, 7 High Completed

RC5 Optimize the minimum air flow set points for VAV boxes High In Process

RC6 Optimize CHW system control High Completed

RC7 Optimize HHW system control High Completed

RC8 Optimize RHW system control Medium Completed

RC9 Optimize FCU control Medium Completed

9

RC10 Optimize steam boiler control Medium In Process

RC11 Optimize the discharge air temperature control for AHU HW4 Low Completed

RC12 Optimize preheat temperature setpoint for AHUs HP1-6 Low Completed

RC13 Program the AHU valve and damper command values to reflect actual measured spring ranges. Low Completed

RC1. Reactivate and optimize heat recovery system for AHUs HW1-4

Units HW 1-4 were designed with a sensible heat recovery system. The heat recovery systems use glycol to cool or heat outside air with exhaust air. At the beginning of the Commissioning process, the heat recovery systems did not work due to broken pumps. It was recommended that the heat recovery system be reactivated to save energy as soon as the recovery pumps have been repaired.

According to the existing PPCL program, the heat recovery system for AHU HW 4 would be enabled when the outside air dry bulb temperature was above 82°F or below 53°F, while the heat recovery systems for units HW 1-3 would be activated when the difference between the exhaust air temperature and outside air temperature was more than 10°F, and turned off when the difference fell below 9°F.

It is recommended that the heat recovery system for AHUs HW1-4 be turned on when the difference between the exhaust air temperature and outside air temperature is greater than 8°F, and turned off when the difference in temperature is less than 6°F.

At the submittal of this report, the pumps have been repaired and the recommended measure has been implemented.

RC2. Optimize damper and return fan control for AHUs HP1-7

For AHUs HP 1-6, it was found that each unit has minimum and maximum OA dampers. The minimum OA damper is on/off controlled. The maximum OA damper is modulating controlled when the economizer is in operation. AHU HP 7 has one on/off controlled OA damper only. Each unit has relief and return dampers with coupled control. Return fan speeds are controlled to maintain return air flow set points. The existing controls of the dampers and return fans are shown in Table 3.

10

Table 3. Pre-RC dampers and return fan control sequence for AHUs HP 1-7

AHU # Condition Max OA

damper control Relief and return damper control

Min OA

damper control

Return fan SS control

Return fan speed

control

HP

1/2/3/6

OA T<65°F Loop

control(MixT, DTSP)

if max OA damper>7psi, loop

control (MinOAFlow, MinOAFlow.Setpoint)

on/off control;

if supply fan is

on, then on, else

off

if supply fan is on, then

on, else off

loop control(SA-

$FixExhaust-$FixOffset)

OA T>65°F 1 psi 1 psi

HP 4

OA T<65°F Loop

control(MixT, DTSP)

Same as HP 1/2/3/6

OA T>65°F

if return fan speed=4 HZ,

Damper= 9 psi, if return fan

speed>5.5 HZ, damper=1psi

1 psi

HP 5

OA T<65°F Loop

control(MixT, DTSP)

Same as HP 1/2/3/6

OA T>65°F

if return fan speed<=4.2 HZ, Damper=12.8psi,

if return fan speed>4.5 HZ, damper=1psi

1 psi

HP 7

OA T<65°F if supply fan is

on, then on (max damper

position), else off (min damper

position)

Loop control (MixT, DTSP)

/ OA T>65°F 1 psi

To further improve the existing control, it was recommended the following economizer control strategy (as shown in Table 4) being implemented.

11

Table 4. Proposed dampers and return fan control sequence for AHUs HP 1-7

AHU # Condition

Max OA Damper control

Relief and return damper

control

Min OA damper control


Return fan speed

control

AHUs HP 1-

6

TOA < TRA and HOA<28 Btu/lb

dry air

Loop control(DT, DTSP-1): Max OA damper, relief dampers and return damper could be couple

control to maintain discharge air temperature at 1°F lower than the

DTSP.

on/off control; if supply fan is on, then on, else off

if supply fan is

on, then on, else

off

loop control(SA-

$FixExhaust-$FixOffset)

TOA > TRA or HOA>28 Btu/lb

dry air 1 psi

AHU HP 7

60°F <TOA < TRA and

HOA<28 Btu/lb dry air

On (Max damper

position)

Loop control (DT, DTSP-1)

/ TOA > TRA or TOA <60°F

or HOA>28 Btu/lb dry air

1 psi (Min damper

position) 1 psi

It was recommended that the economizer for AHUs HP 1-6 be enabled when the outside air temperature is lower than the return air temperature and the outside air enthalpy is lower than 28 Btu/lb dry air for 10 minutes. Because of the bad location of the mixed air temperature sensors, it is recommended that discharge air temperature sensor reading be used as the controlled variable. To eliminate chilled water valve hunting and unnecessary mechanical cooling, the maximum OA damper, relief dampers and return damper should be couple controlled to maintain the discharge air temperature at 1°F lower than the discharge air temperature set points. The control valves would be modulated as needed to maintain the discharge air temperature set points. For AHU HP7, it was recommended that the economizer be enabled when outside air enthalpy is lower than 28 Btu/lb dry air and outside air temperature is lower than the return air temperature but higher than 60°F. Under this circumstance, the OA damper should be opened to its maximum position. Relief dampers and return dampers should be couple controlled to maintain the discharge air temperature 1°F lower than the discharge air temperature set point. A retrofit option also can be considered to convert the OA damper on HP 7 to be able to modulate. This would then allow the damper to be programmed to control in the same way as the maximum dampers on units HP 1-6.

Under non-economizer mode, it was recommended that the maximum OA damper, return damper and relief dampers for AHUs HP 1-7 be commanded to 1 psi, as shown in

12

Table 4.

At the submittal of this report, the recommended measure has been implemented.

RC3. Optimize the discharge air temperature set point for AHUs HP1-7

The discharge air temperature set points for AHUs HP 1 through 7 at the start of commissioning were reset based on the outside air dry bulb temperature, as shown in Table 5.

Table 5. Discharge air temperature set point schedule for AHUs HP 1-7

Units Outside Air Dry Bulb Temperature (°F)

Discharge Air Temperature Setpoint (°F)

AHU HP1-6

55 65 65 63 70 60 80 58 90 55

AHU HP7

50 65 52 63 55 62 70 60 80 58 90 55

It was recommended the following demand based reset schedule be implemented to achieve energy savings.

It was recommended that the discharge air temperature set point should not be allowed to exceed 57°F if the outside air dew point temperature is higher than 55°F. When the outside air dew point temperature is lower than 55°F and the fan speed is below 12 mA for AHU HP 1/3/4/5/6 and below 10 mA for AHU HP 2/7, the discharge temperature set point should be raised half a degree every 10 minutes, but should not exceed 65 °F. When the fan speed is higher than 15.5 mA, the discharge temperature should be dropped half a degree every 10 minutes, but not to fall below 55 °F. When AHU HP 1/3/4/5/6 fan speeds between 12 mA and 15.5 mA, and AHU HP 2/7 fan speeds between 10 mA and 15.5 mA, the discharge air temperature should remain where it is.


RC4. Improve static pressure set point scheduling for AHUs HP1-5, 7

The static pressure set points in place for AHUs HP 1 through 7 at the start of commissioning were reset based on the outside air dry bulb temperature, as shown in Table 6.

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Table 6. Pre-RC Static pressure set point schedule for four AHUs.

Units

Outside Air Dry Bulb

Temperature (°F)

End Static Pressure ST2 Set Point (in. W.C.)

Discharge Air Static Pressure

ST1 Set Point (in. W.C.)

Supply Fan VFD Speed Control

AHU HP1

40 1

2.25

VFD speed=Min(loop control (ST2, ST2

setpoint),loop control (ST1, ST1 setpoint))

65 1.2 75 1.3 85 1.5

AHU HP2

45 0.85

2.95 65 0.95 75 1 85 1.15

AHU HP3

40 0.8

2.0 65 0.9 75 1 85 1.1

AHU HP4

40 1.2

3.0 65 1.4 75 1.6 85 1.8

AHU HP5 / 1.35 3.0

AHU HP6

40 1

3.0 65 1.1 75 1.2 85 1.4

AHU HP7

40 0.9

2.0 65 1.1 75 1.25 85 1.4

As can be seen in the table, every unit except AHU HP5 had an end static pressure reset schedule based solely on the outside air temperature. However, the discharge static pressure set point did not have a reset schedule. The end static pressure control loop and discharge pressure control loop were used to maintain the corresponding set points separately. The minimum loop output was used to control the fan speed.

It was recommended that supply fan speeds be modulated to maintain the optimal end static pressure set points. For protection of the system, there should be an upper limit to discharge static pressure to avoid over pressurization of the ductwork. Recommended static pressure set points and supply fan control strategies are shown in Table 7.

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Table 7. Proposed static pressure set point control for AHUs HP1-5, 7

AHU #

End Static Pressure ST2 Set Point

(in. W.C.)

Discharge Static Pressure ST1 Upper limit

(in. W.C.)


HP1 0.40 2.25

VFD speed=min(loop control (ST2, ST2 setpoint), loop control(ST1,

ST1 Upper limit))

HP2 0.95 2.6

HP3 0.90 2.0

HP4 0.40 3.0

HP5 0.90 2.3

HP7 0.75 2.0


RC5. Optimize the minimum air flow set points for VAV boxes

More than 150 terminal boxes serve different areas in the building. Based on a previous investigation report, more than 90% of the boxes had minimum air flow set points that are greater than 50% of their maximum air flow set points. It might be necessary to have high minimum flows for animal hospital function rooms, such as quarantine, diagnostic, surgery, ICU, x-ray, pharmacy, and animal housing rooms. However, non-hospital function areas such as general offices, conference rooms, corridors, restrooms, and lockers do not need such high minimum air flows. Moreover, when these spaces are occupied, heat loads from the occupants and lighting cause airflow to increase, thus allowing ventilation. Therefore, it is recommended to lower the minimum air flow set points for the following 64 terminal boxes serving non-critical areas (see Table 8). A significant energy savings could be anticipated through the measure. Since all the boxes are pneumatically controlled, the minimum flow settings will have to be physically adjusted on the boxes. It is suggested that AM, OEM and ESL could work together to implement this measure.

Table 8. Minimum air flow set points for non-hospital function areas

Box #

Pre-RC Max CFM

Pre-RC Min CFM

Proposed Min CFM

Box #

Pre-RC Max CFM

Pre-RC Min CFM

Proposed Min CFM

1-11 530 265 140 6-11 450 360 60 1-12 460 230 70 6-12 225 225 40 1-13 450 575 50 6-16 930 465 90 1-14 565 285 80 6-17 225 225 20 1-15 825 415 150 6-19 2,605 1,565 260 1-16 800 400 150 6-24 540 540 50 1-17 660 660 70 6-31 2,610 1,305 260 1-20 1,400 1,400 260 6-32 340 170 60 2-7 2,020 2,400 200 6-35 800 760 110 2-8 2,640 1,320 260 6-36 225 225 60

15

2-9 1,980 990 200 6-46 300 150 40 2-10 720 360 70 7-1 480 275 110 3-2 510 300 50 7-2 1,480 715 240 3-3 745 375 240 7-3 1,850 925 300 3-9 395 395 40 7-4 1,330 795 270 3-13 1,470 1,470 150 7-5 630 315 120 3-15 395 395 40 7-6 2,300 1,150 360 3-16 230 205 50 7-7 1,600 800 160 3-23 590 590 60 7-8 875 440 270 3-24 860 400 220 7-9 875 440 280 3-26 220 110 70 7-11 935 470 300 3-27 810 600 80 7-12 640 320 210 4-2 540 270 90 7-13 825 415 280 4-5 250 125 60 7-15 1,000 500 200 4-8 745 370 100 7-16 1,120 560 330 4-13 565 285 100 7-17 930 465 290 4-16 670 465 150 7-18 385 300 150 5-2 1,250 450 160 7-19 250 250 140 5-4 1,020 510 120 7-20 870 435 300 5-6 1,000 500 120 7-21 465 270 170 6-3 600 450 60 7-22 885 445 240 6-9 540 540 320 7-23 710 355 110

RC6. Optimize CHW system control

RC6.1 Implement CHW secondary differential pressure set point reset schedules.

At the start of commissioning, the CHW secondary differential pressure set point (DPSP) was reset based on the outside air dry bulb temperature (OADBT), as shown in Table 9, which did not always fully reflect building demand. It was found in the field that excessive pressure was reduced by the CHW control valves, as shown in Table 10, thereby resulting in energy waste.

Table 9. Pre-RC CHW secondary DPSP control.

OADBT (°F) CHW Secondary DPSP (psi) 20 5

50 14

65 15

75 16

85 18

16

Table 10. Pre-RC CHW side pressure investigation for AHUs

AHU CHW side pressure (psig)

before coil after coil after valve HP1 47 46 33 HP2 45 42 34 HP3 47 46 34 HP4 47 46 33 HP5 47.5 47 33.5 HP6 47 46 35 HP7 47 46 34 HW1 49 47 35 HW2 49 47 35 HW3 51 50 34 HW4 49 44 34

It was recommended the CHW secondary DPSP be reset based on the CHW control valve position of AHU HP1-7 and HW1-4. The valves should be sampled periodically, e.g. every 5 minutes, to determine their position, and the differential pressure set point CWDPSP should be raised or lowered, for example 0.5 psi each time, to maintain the maximum open valve between 80 and 90 percent open. The upper and lower limits for CHW secondary differential pressure should be 18 psi to 4 psi.


RC6.2 Optimize CHW pump staging control.

There are two identical chilled water pumps in the building with VFDs. The PPCL programming shows that when the CWLP is above 110, the lead pump is activated. When the CWLP is above 190, the lag pump is brought on and commanded to the same speed as the lead pump. Both pumps remain in operation until the CWLP falls below 160, after which the lag pump is turned off. When the CWLP is below 90, the lead pump is also turned off. Then the CHW return control valve modulates based on the CWLP. This control strategy may result in unsteady lag pump operation when the lag pump is brought on after the CWLP reaches 190 and turned off after the CWLP falls below 160.

It was recommended that when the CWLP is above 110, the lead pump should be activated at minimum speed and the CHW return control valve should be modulated based on the CWLP to maintain the secondary differential pressure setpoint. When the return control valve exceeds 90% for 5 minutes, then the control valve remains 100% open and the lead pump begins to modulate to maintain the secondary DPSP. When the lead pump speed exceeds 90% for 5 minutes, the lag pump should be brought on and commanded to the same speed as the lead pump. Both pumps should remain in operation until they fall below 40% speed, after which the lag pump should be turned off. Then when the CWLP falls below 100, the lead pump should also be turned off. After that the

17

CHW return control valve should be modulated based on the CWLP to maintain the secondary differential pressure setpoint.


RC7. Optimize HHW system control

RC7.1 Implement HHW secondary DPSP reset schedules.

At the start of commissioning, the HHW secondary DPSP was reset based on OADBT, as shown in Table 11, which did not completely reflect the demand. In addition, the HHW secondary DPSP has currently been overridden to 20 psi.

Table 11. Pre-RC HHW secondary loop DPSP control.

OADBT (°F) HHW DPSP (psi) 40 16

65 14

75 13

85 13

It was recommended that the HHW DPSP be reset based on the HHW flow rate as shown in Table 12. The HHW flow rate should be sampled periodically, such as every 5 minutes. The upper and lower limits for HHW secondary differential pressure should be 20 psi and 6 psi, respectively.


Table 12. Proposed HHW secondary loop DPSP.

HHW Flow Rate (gpm) HHW DPSP (psi) 30 6

50 9

80 12

120 15

160 18

210 20

RC7.2 Optimize HHW pump staging control.

There are two identical hot water pumps in the building with VFDs. The PPCL shows that when the HWLP is above 110, the lead pump is activated. When the HWLP is

18

above 190, the lag pump is brought on and commanded to the same speed as the lead pump. Both pumps remain in operation until the HWLP falls below 160, after which the lag pump is turned off. When the HWLP is below 85, the lead pump is also turned off. Then the HHW return control valve is modulated based on the HWLP. This control strategy may result in unsteady lag pump operation when the lag pump is brought on after the HWLP reaches 190 and turned off after the HWLP falls below 160.

It was recommended that when the HWLP is above 110, the lead pump should be activated at minimum speed and the HHW return control valve should be modulated based on HWLP to maintain the secondary differential pressure setpoint. When the return control valve exceeds 90% for 5 minutes, then the control valve remains 100% open and the lead pump begins to modulate to maintain the secondary DPSP. When the lead pump speed exceeds 90% for 5 minutes, the lag pump should be brought on and commanded at the same speed as the lead pump. Both pumps should remain in operation until they fall below 40% speed, after which the lag pump should be turned off. When HWLP falls below 100, the lead pump should also be turned off. After that the HHW return control valve should be modulated based on the HWLP to maintain the secondary differential pressure setpoint.


RC8. Optimize RHW system control

RC8.1 Implement RHW secondary DPSP reset schedules.

At the start of commissioning, the RHW secondary DPSP was fixed at 20 psi, which did not always reflect the actual flow demand and sometimes caused the RHW pump to operate unnecessarily. It was recommended that a new reset schedule be implemented to more optimally run the pumps.

The RHW secondary DPSP can be reset based on the secondary differential temperature. The supply and return temperatures should be sampled periodically, such as every 10 minutes, to determine the differential temperature. The secondary DPSP should be raised or lowered, for example 0.5 psi each time, to maintain the secondary differential temperature between 35°F and 40°F. The upper and lower limits for RHW secondary differential pressure should be 18 psi and 4 psi, respectively.


RC8.2 Optimize RHW pump staging control.

There are two identical reheat water pumps in the building with VFDs. The PPCL shows that one pump is used as a backup pump. The active pump speed is modulated to maintain a fixed secondary DPSP. The return control valve is modulated to maintain the secondary supply temperature at its set point, and the supply temperature set point is

19

adjusted to maintain the secondary return temperature at its set point, which is reset based on outside air dry bulb temperature.

It was recommended that when the variable $DPLP is above 110, the return control valve remain 100% open and the duty pump be activated and modulated to maintain the secondary DPSP. When $DPLP falls below 90, the duty pump should be turned off. After that, the RHW return control valve should be modulated based on $DPLP to maintain the secondary differential pressure set point.


RC9. Optimize FCU control

Five FCUs serve the mechanical rooms. At the start of commissioning, when the space temperature in the mechanical rooms started beyond the temperature range, from 70°F to 78°F, the exhaust fans would be turned off while the supply fans would be turned on, and the heating and cooling coil valves would be controlled by coupled control to maintain the space temperature set point of 75°F. When the space temperature fell between 73°F to 75°F, the supply fans would be turned off and the cooling and heating valves would be set to 8 psi.

It was recommended that the exhaust fans be turned on when the space temperature in the mechanical rooms exceeds 85°F, outside air temperature falls below 82°F, and the outside air enthalpy is lower than 32 Btu/lb dry air for 10 minutes. Otherwise, the exhaust fans should be shut off. When exhaust fans are off and the space temperature in the mechanical rooms exceeds 85°F, the supply fan for FCU should be turned on, and the cooling coil valves should be fully opened until the space temperature drops to 80°F. When the space temperature drops below 60°F, the supply fan for FCU should be turned on and the heating coil valves should be fully opened until space temperature rises to 65°F.


RC10. Optimize steam boiler control

Currently, the steam boiler is cycled on at 80 psig and off at 85 psig. There are two regulated pressures leaving the boiler, 80 psig and 15 psig. The 15 psig line is shut and no longer in use. The 80 psig line is still in use and distributes steam to the equipment shown in Table 13.

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Table 13. Steam pressure requirement for steam equipment.

Steam Equipment

Room #

Min Steam Pressure

(psig)

Max Safety Pressure

(psig) Steam Requirements Notes

AMSCO 470 Parts Washer 106 30 80 Steam quality >97% /

AMSCO Parts Dryer 106 NA NA NA Generates its own

steam. AMSCO 3041

Auto Clave 107 50 80 Steam quality >97% /

AMSCO 3043 Auto Clave 107 50 80 Steam quality >97% /

AMSCO 3012 Auto Clave 134 50 80 Steam quality >97% /

As can be seen in the table, the minimum steam pressure requirement is about 50 psig. Additionally, according to the boiler manufacture representative, it is safe to drop the pressure setpoint to 50 psig. Considering the pressure drop across the pressure regulator and steam lines, it is recommended that the boiler be cycled on at 60 psig and off at 65 psig. Field test should be conducted before implementing this measure. ESL will work together with OEM to perform the test and implement this measure.

RC11. Optimize discharge air temperature control for AHU HW4

When commissioning began, the PPCL programming showed that the discharge air temperature set point for AHU HW 4 was reset based on outside air dry bulb temperature, and that the reheat valves were modulated to maintain the space temperature set points, as shown in Table 14.

Table 14. Pre-RC preheat and discharge air temperature set points for AHU HW4

AHU #

Outside Air Dry Bulb Temperature

(°F)

Preheat Temperature Set point (°F)

Discharge Air Temperature Set point (°F)

HW4 40 64 67 55 60 63 90 60 58

Since HW4 terminal boxes have full DDC control, it was recommended that a discharge air temperature reset schedule for HW4 could be based on terminal box valve positions to minimize reheat and reduce chilled water consumption. The valves should be sampled periodically, e.g. at five minute intervals, to determine their positions, and the discharge air temperature set point should be raised or lowered as needed to maintain the minimum open valve between 10 and 20 percent open. The discharge air temperature set point should be reset between its upper and lower limits. The lower limit should be 52 °F. The upper limit of the set point should be based on the outside air dew point temperature.

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When the outside air dew point temperature is higher than 55 °F, the upper limit should be 57 °F. When the outside air dew point temperature is lower than 55 °F, the upper limit should be 65 °F.


RC12. Optimize preheat temperature setpoint for AHUs HP1-6

The preheat temperature set points for AHUs HP 1 through 6 and HW4 at the start of commissioning were reset based on outside air dry bulb temperature, as shown in Table 15.

Table 15. Pre-RC preheat set points for AHUs HP 1-6


Preheat Temperature Setpoint (°F)

HP 1/3/4

55 60 65 58 70 55 80 53 90 50

HP 2/5 / 50 HP 6 / 55

These preheat set points may cause simultaneous heating and cooling, thereby resulting in energy waste. It was recommended that these preheat temperature set points be set to 40°F. Preheat valves should be modulated to maintain the preheat temperature set points.


RC13. Program the AHU valve and damper command values to reflect actual measured spring ranges

The spring ranges for each of the AHU valves and max OA damper actuators were measured and compared with the ranges in place in the PPCL programming at the start of commissioning. Table 16 below shows the results of this comparison.

Table 16. Programmed and measured AHU valve spring ranges

AHU # % Open

CHW PHW Max OA Damper

Pre-RC PPCL (psi)

Measured (psi)

Pre-RC PPCL (psi)

Measured (psi)

Pre-RC PPCL (psi)

Measured (psi)

HP1 0 15 12 15 8 7 5

22

100 8 3 1 3 14 18

HP2 0 18 17 18 10 7 8

100 0 9 1 4 14 16

HP3 0 18 13 18 9 7 5

100 1 3 1 3 14 13

HP4 0 / / 18 9 7 8

100 / / 1 4 14 13

HP5 0 18 13 18 9 7 NA

100 1 3 1 4 14 NA

HP6 0 / / / / 7 8

100 / / / / 14 15.5

HP7 0 18 11 / / 7 3

100 1 2 / / 14 13

HW1 0 18 12 18 11 / /

100 1 3 1 4 / /

HW2 0 18 12 15 11 / /

100 7 3 4 4 / /

HW3 0 14 14 15 11 / /

100 7 3 4 4 / /

HW4 0 18 10 13 9 / /

100 1 2 4 3 / /

It was recommended that the ranges given in the PPCL programming be updated for all valves and damper actuators where this is needed in order to allow the valves and dampers to fully open and close. This might have a preventive maintenance impact since the valves and dampers would not be as likely to wear out as quickly if they are able to fully open and close.


Retro Commissioning Results

Savings Analysis

At the time of submittal of this report, 11 out of 13 RC measures have been implemented. However, because post RC data are not accumulated sufficiently to perform the savings analysis, this report does not contain measured savings results and will be updated in the future. Based on the understanding of the current system situation and engineering calculation, it is estimated that implementation of the recommended RC measures would result in about $75,000 annual energy cost savings. The value was based on a rate of $9.602/MMBtu for chilled water, $13.099/MMBtu for hot water, and $0.092/kWh for electricity.

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Comfort Improvements

One of the primary objectives of Retro Commissioning is to improve occupant comfort levels in buildings. The major comfort issues indicated by the building proctor in this building before commissioning were temperature fluctuation and high humidity. It is believed that the comfort complaints were related to the AHU discharge air temperature and static pressure set point reset strategy described previously. The pre-RC AHU discharge air temperature and static pressure set points were reset based on OA temperature only, which can not reflect the demand and especially not the dehumidification demand. Therefore, this set point may cause the temperature fluctuation and high humidity. RC measure 3 and 4 address this issue, and should help eliminate these comfort complaints.

MAINTENANCE ISSUES

Observed Maintenance Related Issues

During the RC process several maintenance related issues were observed that potentially waste energy, cause comfort problems, and/or prevent certain RC measures from being implemented. In order to improve building comfort and maximize potential energy savings, it was recommended that these issues be addressed. The items found are summarized in Table 17 with priority ratings and implementation status as of the report submittal date.

Table 17. Observed maintenance related issues.

# Maintenance Related Issues Priority Completion Date

1

Calibrate the following sensors: CHW primary supply/return pressure sensors (Supply: apogee 50.78psi, field 43psi; Return: apogee 40.99, field 38); CHW secondary supply pressure sensors(apogee 55.97, field 51); HW secondary supply/return pressure sensor(Supply: apogee 57.88, field 60; Return: apogee 37.8, field 40);

1 12/10/2007

2

Calibrate the following flow sensors: HP1 OA flow sensor(Apogee: 1,250cfm, field 1,885cfm) (flow tubes is very dirty), HP1 supply air flow sensor(Apogee: 17,281cfm, field 14,100cfm)

1 12/10/2007

3

Calibrate the following sensors: HP3 return air temperature sensor(apogee 72.28, field 69.3); HP6A OA temperature sensor(apogee 85.6, field 79.8); HW-2 OA temperature sensor(apogee 88.78, field 85)

1 12/10/2007

4 Calibrate HP7 mixed air temperature sensor (apogee 77.8, field 82.1). 1 12/10/2007

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5

Calibrate the following discharge static pressure sensors: HP1 (Apogee 2.21'', field 1.72''); HP4 (Apogee 1.83'', field 2.07''); HP7 (Apogee 1.33'', field 1.53'') and an end static pressure sensors: HP4 (Apogee 1.80'', field 1.53'')

1 12/10/2007

6 HP2 OA damper sticks. Its CHW coil is partially stopped up with 7 psi DP. 1 9/14/2007

7

HP5 min. OA filters are missing. Its OA heat recovery coil is very dirty. There is condensate leaking on the floor, but its P-trap is ok. 3 of the EP switches serving this AHU are leaking air. Its preheat pump coupler is broken.

1 9/28/2007

8 HP2 HHW coil is partially stopped up with 8 psi DP. RA and OA filters and recovery coils are very dirty. 1 9/14/2007

9 HP6A HHW coil stopped up with 18 psi DP. Relief air damper stuck in closed position. 1 10/1/2007

10 HP7 filters are dirty. OA damper stick during operation. 1 9/14/2007

11 HW3 heat recovery motor defective. All filters and heat recovery coils are dirty. Both CHW and HHW are partially stopped up with 8 psi DP.

1 9/24/2007

12 Check and clean the following recovery coil: HP1/3/4/6A; HW2 2 9/14/2007

13 Filters of HP1/3/6; HP4 pre filters; HW2 return filter and OA pre filter are dirty; 2 9/14/2007

14 Clean the following strainer: HP4 HHW strainer(Valve 100% open, DP cross strainer 17 psi); 1 9/12/2007

15

Check and repair the following items: HP1 min-OA Damper (stuck); belt loose on HP1 return fan; HP1 HW control valve (100% open, DP 12 psi); HP3 CHW valve stem broke; HP6A return damper housing is very loose from duct wall; Max. OA damper stuck in closed position.

2 10/5/2007

16 HW-2 heat recovery pump doesn't work. 1 9/25/2007

17 Water is dripping out of corner of AHU W1 and drain line is open. Its mech. room has 1"-2" of water on the floor. Drain ok, but the drain is at highest part of mech. room.

2 9/12/2007

18 Cleaned preheat coil on HP3 3 8/29/2007

25


19 HP5 condensate leaking on the floor 2 8/12/2007

20 The supply flow monitors on HP 1-7 need to be cleaned 2 9/21/2007

21 HW3 heat recovery pump motor is defective, needs to be worked on. 1 10/4/2007

22 HW4 filters, recovery coil, preheat coil, and CHW coil are very dirty. 1 11/2/2007

23 Replaced a total of 24 EP switches on HP/HW units 2 9/28/2007

24

Check the VFD for CHW pump # 2. It was field found that the VFD was in "auto", and when Apogee signal turned on the pump, VFD output signal in the field always stayed about 40%-42% speed and won't response to any signal changes either from Apogee or manual override.

1 12/6/2007

25 Replaced coupler on HP3 preheat pump 8/30/2007

26 Cleaned preheat coil on HP3 8/29/2007

27 Replaced leaking EP's on HP3 8/31/2007

28 Replaced a total of 24 EP switches on HP/HW units 9/28/2007

29 Replaced EP switches on HW4 11/6/2007

CONCLUSIONS

The Veterinary Medicine Large Animal Clinic has been a part of the A&M system since 1993. High energy consumption and comfort problems in the building made it a good candidate for Retro Commissioning. Thus far eleven of the thirteen recommended RC measures and twenty-nine maintenance related issues have been implemented in the building. It was predicted that implementation of the proposed RC measures would reduce costs by about $75,000 per year. The value is based on a rate of $9.602/MMBtu for chilled water, $13.099/MMBtu for hot water, and $0.092/kWh for electricity. After complete implementation of these measures, better energy efficiency will occur in the building, as well as an increase in the productivity of occupants who will be more comfortable in their working environment. Additionally, a number of maintenance issues were identified and implemented throughout the commissioning process. The

26

resolution of these maintenance issues helped maximize energy savings and comfort levels in the building. In this way, the Retro Commissioning process has helped the Texas A&M University campus move forward in its quest for energy efficiency.

27

APPENDIX A – HVAC AS-BUILT INFORMATION Table A - 1. Building pumping information

Building CHW System HW System

Number of pumps 2 2

Pump control source Apogee Apogee

Pump speed control VFD VFD

Pump speed control method ΔP ΔP

Bldg Valve control method ΔP ΔP

Piping system type a variable flow with two-way piping

a combination of two-way piping and three-way piping with bypass

Nameplate GPM 1320 450 Nameplate Head (ft) 110 85

Nameplate HP 50 25

Table A - 2. HVAC system AHU airflow design information.

Unit

Design Maximum Supply &

Maximum OA CFM

Design Minimum OA CFM

Supply Motor

HP

Relief Motor HP Service

HP-1 19,300 4,630 30 7.5 Administrative area HP-2 13,300 3,725 20 5 Administrative and EQX area HP-3 15,400 4,620 25 7.5 ICU area HP-4 9,500 2,850 15 5 RAD area HP-5 14,000 4,480 20 7.5 FAU area HP-6 43,200 12,960 76 20 EQS, PHM, CSS, FAS and EWSHP-7 23,000 3,220 20 10 Office area (second floor) HW-1 16,000 - 10 7.5 ESW area HW-2 16,000 - 10 7.5 EMW area HW-3 16,000 - 10 7.5 FAW area HW-4 7,450 - 10 2 ISO area Total 193,150 36,485 246 87

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APPENDIX B – FIELD MEASUREMENT RECORDS

CHW WATER LOOP INFORMATION

LOOP SIDE MEASUREMENTS

LOCATION TEMPERATURE (°F) PRESSURE (psi) COMENTSApogee Field Apogee Field

Primary Supply 43.9 50.78 43 Primary Return 60.6 40.99 38

Secondary Supply 44.09 44.7 55.97 51

Secondary Return 61.13 61.0 39.2 41

PUMPS AND VALVE POSITIONS: # 1 □ CONSTANT X VFD Running: X Yes □ No Speed 58%(A), 67%(F) # 2 □ CONSTANT X VFD Running: □ Yes X No Speed # □ CONSTANT □ VFD Running: □ Yes □ No Speed # □ CONSTANT □ VFD Running: □ Yes □ No Speed # □ CONSTANT □ VFD Running: □ Yes □ No Speed # □ CONSTANT □ VFD Running: □ Yes □ No Speed

VALVE POSITION COMMENTS: N.O.

CONDITION

VALVE POSITION COMMENTS:

CONDITION Additional comments:

29

HW WATER LOOP INFORMATION

CHWS

CHWR

P1

P2

PrimaryReturn Temp.

PrimaryReturn Pressure

SecondaryReturn Pressure

SecondarySupply Pressure

PrimarySupply Pressure

PrimarySupply Temp.

LOOP SIDE MEASUREMENTS LOCATION TEMPERATURE (°F) PRESSURE (psi) COMENTS

Apogee Field Apogee Field Primary Supply 134.55 133.8 43 Primary Return 105.1 39

Secondary Supply 134.7 57.88 60


PUMPS AND VALVE POSITIONS: # 1 □ CONSTANT X VFD Running: □ Yes X No Speed # 2 □ CONSTANT X VFD Running: XYes □ No Speed 38%(A), 45%(F) # □ CONSTANT □ VFD Running: □ Yes □ No Speed # □ CONSTANT □ VFD Running: □ Yes □ No Speed # □ CONSTANT □ VFD Running: □ Yes □ No Speed # □ CONSTANT □ VFD Running: □ Yes □ No Speed


CONDITION


CONDITION Additional comments:

30

RHW WATER LOOP INFORMATION

HWS

HWR

P1

P2

PrimaryReturn Temp.

PrimaryReturn Pressure

SecondaryReturn Pressure

SecondarySupply Pressure

PrimarySupply Pressure

PrimarySupply Temp.

CV

DP

LOOP SIDE MEASUREMENTS LOCATION TEMPERATURE (°F) PRESSURE (psi) COMENTS

Apogee Field Apogee Field Primary Supply 139.4 52 Primary Return 105.4 32

Secondary Supply 130.7 129.5 72.7 74


PUMPS AND VALVE POSITIONS: # 1 □ CONSTANT X VFD Running: X Yes □ No Speed 78% # 2 □ CONSTANT X VFD Running: □ Yes X No Speed # □ CONSTANT □ VFD Running: □ Yes □ No Speed # □ CONSTANT □ VFD Running: □ Yes □ No Speed # □ CONSTANT □ VFD Running: □ Yes □ No Speed # □ CONSTANT □ VFD Running: □ Yes □ No Speed

VALVE POSITION COMMENTS: Return valve DDC

CONDITION Good


CONDITION Additional comments: D.P. set point - 20

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AHU Information AHU: HP1

AIR-SIDE MEASUREMENTS

POSITION FLOW (CFM) TEMP (°F) S.P. (in WG) CO2 (PPM) RH (%) # Desc Apog. Field Apog. Field Apog. Field Apog. Field Apog Field 1 1250 1885 87.3 -0.16 2 0 3 Closed 4 Closed 5 0.12 6 73.34 72.7 -0.89 7 -0.65 8 75.75 75.6 -0.79 9 -0.80

10 75.41 75.9 3.15 11 2.65 12 17281 14100 54.53 52.5 2.25 WATER-SIDE MEASUREMENTS FAN MEASUREMENTS

LOCATION TEMPERATURE PRESSURE VFD FAN SPEED Apogee Field 1 2 Apogee Field

CHWS 44.9 44 Supply 18.19 mA 82% CHWR 54.2 *38 **36 Return 14.57 mA 69% HHWS 138.1 48 Exhaust HHWR 115.1 48 **36

CHW VALVE %OPEN 100% *Measurement taken before valve HHW VALVE %OPEN 100% **Measurement taken after valve CHW

Valve HHW Valve

OA Damper 1 OA Damper

2

RA Damper 1 RA Damper 2

Normal Status N/O N/O N/C N/C N/C N/C Valve Range 3-12 3-8 6.5-16 5-18 7.5-16 8-14

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Notes: Flow tubes very dirty in blower suction area (return fan??); In economizer RA damper closes before OA damper opens and trips supply fan on static; OA Damper 2 (Max OA damper) sticks, or is stuck; Condensate leaking on floor; Belt loose on return fan; Filters dirty; Min OA damper broke

33

AHU Information AHU: HP-2


POSITION FLOW (CFM) TEMP (°F) S.P. (in WG) CO2 (PPM) RH (%) # Description Apog. Field Apog. Field Apog Field Apog Field Apog. Field

1 3227 3190 82.1 -0.018 2 82.1 -0.511 3 -1.28 4 77.97 76.4 -1.318 5 75.44 76.9 -1.398 6 -1.97 7 9659 11000 56.27 55.9 3.10 8 9 8242 6700 75.5 74.6 -0.054

10 -0.22 WATER-SIDE MEASUREMENTS FAN MEASUREMENTS

LOCATION TEMPERATURE PRESSURE VFD FAN SPEED

Apogee Field 1 2 Apogee Field

CHWS 45.4 45 psi Supply 98%

CHWR 55.5 38 *35 psi Return 24%

HHWS 146.1 48 Exhaust HHWR 123.3 45 *35

CHW VALVE %OPEN 100% *Measurement taken after the valve HHW VALVE %OPEN 100% CHW

Valve HHW Valve

OA Damper 1 OA Damper 2

RA Damper 1 RA Damper

2

Return Damper

Status N/O N/O N/O N/C N/C N/C N/C Range 9-17 psi 4-10 7-16 8-16 8-16 8-17 8-17

Notes: Outside air filters very dirty; OA coil dirty; Preheat pump coupler broke; OA damper needs to be worked on; hard to open

34


AIR-SIDE MEASUREMENTS POSITION FLOW (CFM) TEMP (°F) S.P. (in WG) CO2 (PPM) RH (%)

# Description Apog. Field Apog. Field Apog. Field Apog. Field Apog. Field 1 -0.015 2 1913 2070 89.8 -0.320 3 0 4 0 5 -0.508 6 6600 72.28 69.3 0.384 7 -0.560 8 81.59 79.6 -0.605 9 -0.651

10 95.5 85.3 3.120 11 2.501 12 12545 56.44 57.95 2.057

WATER-SIDE MEASUREMENTS FAN MEASUREMENTS


CHWS 45.1 45 Supply 18.27 mA 54 Hz CHWR 53.6 41 38 Return 14.8 74% HHWS 137.9 *39 39 Exhaust HHWR 113.5 **34 38

CHW VALVE %OPEN 100% *Measurement taken before strainer HHW VALVE %OPEN 100% **Measurement taken after valve

CHW

Valve HHW Valve

OA Damper 1

OA Damper 2

RA Damper 1

Ra Damper 2

Return Damper

Status N/O N/O N/O N/C N/C N/C N/O Range 3-13 3-9 8-15 5-13 9-12 8-13 9-14 Notes: CHW valve stem broke; Filters dirty;

35



POSITION FLOW (CFM) TEMP (°F) S.P. (in WG) CO2 (PPM) RH (%) # Description Apog. Field Apog. Field Apog. Field Apog. Field Apog. Field 1 932 950 2 8800 74.56 73.9 -0.84 3 74.8 73.6 -0.86 4 5 56.8 56.3 2.33 6 69.88 70.7 -0.30 7 0.21 8 2800 9 4530 10 6350 11 2.70 12 -1.48 WATER-SIDE MEASUREMENTS FAN MEASUREMENTS


CHWS 46.2 42 Supply 84% CHWR 54.7 36/35 Return 77% HHWS 51/34 Exhaust HHWR 33/32

CHW VALVE %OPEN 100% HHW VALVE %OPEN 100%

CHW

Valve HHW Valve

OA Damper 1 OA Damper 2 RA Damper 1 Ra Damper 2

Normal Status N/O N/C N/C N/C Valve Range 4-9 8-13 8-13 8-13

36



POSITION FLOW (CFM) TEMP (°F) S.P. (in WG) CO2 (PPM) RH (%) # Descri. Apog Field Apog. Field Apog. Field Apog. Field Apog Field 1 2139 610 2 3 Mixed air 73.34 72.1 -0.830 4 5 Preheat 72.91 71.1 -0.900 6 6943 -1.10 7 Discharge 54.6 1.95 8 Aft. HEPA 56.1 1.78 9 Return Air 70.8 70.5 -0.250

10 Discharge -0.255 WATER-SIDE MEASUREMENTS FAN MEASUREMENTS


CHWS 44.6 42 psi Supply 72% CHWR 52.0 37 *35 psi Return 30% HHWS 126.6 46 Exhaust HHWR 107.9 44 *38

CHW VALVE %OPEN 100% *Measurement taken after valve HHW VALVE %OPEN 100% CHW Valve HHW Valve OA Damper 1 OA Damper 2 RA Damper 1 Ra Damper 2

Normal Status N/O N/O N/C N/C Valve Range 3-13 psi 4-9 9-17 7-16

Notes: Condensate leaking on floor; 3 – EP switches leaking air; Coupler broke on preheat pump; OA coil completely stopped up; filter missing before coil

37



POSITION FLOW (CFM) TEMP (°F) S.P. (in WG) CO2 (PPM) RH (%) # Descrip. Apog. Field Apog. Field Apog. Field Apog. Field Apog. Field 1 7600 6850 85.6 79.8 -0.78 73.7 2 79.8 -0.29 3 -1.40 4 Mixed Air 71.6 70.6 -1.42 5 71.6 70.6 -1.52 6 75.5 3.57 7 57.2 55.8 -2.94 8 2.32 9 RA 71.0 70.1 -0.70

10 -0.08 11 -1.007 WATER-SIDE MEASUREMENTS FAN MEASUREMENTS


CHWS 45.5 44 Supply 80% CHWR 57.9 *38/36 Return 58% HHWS 138.8 **51/50 Exhaust HHWR 84.2 *33/33

CHW VALVE %OPEN 100% *Before return valve/After return valve HHW VALVE %OPEN 100% **Before strainer/After strainer CHW Valve HHW Valve OA Damper 1 OA Damper 2 RA Damper 1 Ra Damper 2

Normal Status N/C N/C N/C N/C Valve Range 8-16 8-15.5 8-14 8-13

Notes: Relief dampers stuck (closed); Outside dampers stuck (closed); Return damper housing very loose from duct wall; Filters dirty; OA heat recovery coil dirty

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AHU Information AHU: HP- 7


POSITION FLOW (CFM) TEMP (°F) S.P. (in WG) CO2 (PPM) RH (%) # Description Apog Field Apog Field Apog Field Apog Field Apog Field 1 Discharge 54.4 55.28 1.61 2 After coils -0.76 3 After filter 82.1 77.84 -0.40 4 Before filter -0.33 5 O.A. 98.0 +0.03 6 Mixed R.A. 73.5 -0.05

7 After RA damper 73.44 73.5 -0.05

8 R.A. 9161*1 6050 9 R.A. 2090



CHWS 44.3 48 Supply 43Hz CHWR (before valve) 57.3 42 Return 31% CHWR (after valve) 39 Exhaust CHW VALVE %OPEN 100%

CHW

Valve Relief damper RA Damper

1 Ra Damper 2 OA Damper

Normal Status N.O. N.C. N/C N/C N/C Valve Range 2-11psi 3 ½ - 16 psi 5 -13 psi 4-14psi 3-13psi

Notes: - Filters are dirty. - There is a duct off of relief that is marked supply to EQS 125 and negative in the duct. - No preheat coil. - O.A. damper sticks.

39

AHU Information AHU: HW-1


POSITION FLOW (CFM) TEMP (°F) S.P. (in WG) CO2 (PPM) RH (%) # Description Apog. Field Apog. Field Apog. Field Apog. Field Apog. Field 1 Outside Air 7,240 73.6 -0.07 2 3 Preheat 74.68 73.9 4 -1.51 6 Discharge 62.53 62.3 +0.16 7 Return Air 68.56 68.9 -0.520 9 -1.648

10 Exhaust 11,60

0 +0.10

4 WATER-SIDE MEASUREMENTS FAN MEASUREMENTS


CHWS 46.4 47psi Supply CHWR 55.2 40psi 37psi Return HHWS 138.5 N/A 47psi Exhaust HHWR 130.1 41psi


CHW Valve HHW Valve OA Damper 1 OA Damper 2 RA Damper 1 Ra Damper 2Normal Status N/O N/O Valve Range 3-12psi 4-11psi

Notes: Heat recovery pump for HW-1 does not work (motor defective); The filters and HRC coil are very dirty. Steam boiler: 1 outlet – 15psi steam; 1 outlet – 80psi steam; Gauge on boiler – 85psi; Max. W.P. – 150psi; Industrial Boiler Co. Mod. PPF50L3PVGAS Steam lbs. per hour – 1725 (2219 MBH)

40


AIR-SIDE MEASUREMENTS POSITION FLOW (CFM) TEMP (°F) S.P. (in WG) CO2 (PPM) RH (%)

# Description Apog. Field Apog. Field Apog. Field Apog Field Apog. Field 1 9170 88.78 85.0 -0.116 2 -0.095? 3 4 5 -1.331 6 61.95 60.7 0.648 7 70.1 69.7 8 9 12300



CHWS 46.1 45 Supply N/A N/A CHWR 58.9 *40 **38 Return N/A N/A HHWS 139.3 *49 **46 Exhaust N/A N/A HHWR 133.7 41


CHW Valve HHW Valve OA Damper 1 OA Damper 2 RA Damper 1 Ra Damper 2Normal Status N/O N/O N/C (open) N/C (closed) N/C (open) Valve Range 3-12 4-11 7.5-15 8-15 8-14

*Measurement taken before valve **Measurement taken after valve Notes: Recovery coil very dirty Heat recovery pump shows to be on in Apogee, but pump does not operate Filters in return (b/w 7&8) & filters in OA (b/w 1&2) very dirty -1.331

41



POSITION FLOW (CFM) TEMP (°F) S.P. (in WG) CO2 (PPM) RH (%) # Description Apog Field Apog. Field Apog. Field Apog. Field Apog. Field 1 O.A. 9190 91.7 92.6 -0.08 2 After H.R.C. 91.86 92.4 3 After all Coils 66.57 65.1 -1.47 4 Discharge 0.14 5 Return 73.91 72.9 -0.42 6 After filter 72.9 -0.66 7 After HRC 72.9 -0.88 8 Discharge 12800 73.5 0.14


LOCATION TEMPERATURE PRESSURE VFD FAN SPEED Apogee Field 1 2(after valve) Apogee Field

CHWS 45.5 49 psi Supply CHWR 55.1 41 40 Return HHWS 138 49 47 Exhaust HHWR 133 41


CHW Valve

HHW Valve

OA Damper 1 OA Damper 2 RA Damper 1 Ra Damper 2

Normal Status N.O. N.O Valve Range 3-14 psi 4-11 psi

Notes: Heat recovery pump motor is defective.

42



POSITION FLOW (CFM) TEMP (°F) S.P. (in WG) CO2 (PPM) RH (%) # Description Apog. Field Apog. Field Apog. Field Apog. Field Apog Field 1 O.A. 5900 87.3 -0.42 2 After filter 3 Preheat 4 After CHW 58.3 -2.47 5 Discharge 58.5 1.05 6 After HEPA 7 Return air 68.9 -0.4 8 After coil 76.5 -0.81 9 Discharge 5250 77.7

Filter and coils very dirty. WATER-SIDE MEASUREMENTS FAN MEASUREMENTS


CHWS 44.8 49 psi Supply CHWR 55.3 43 38 Return HHWS 131.3 48 Exhaust HHWR 125.5 38 35


CHW

Valve HHW Valve

OA Damper RA Damper

Normal Status N.O. N.O. Valve Range 2-10psi 3-9psi

43

APPENDIX C – PRE-RC CONTROL SETTINGS

Table C - 1. Pre-RC CHW secondary loop differential pressure set point control.

Outside Air Dry Bulb Temperature (°F) CHW Secondary Loop Differential Pressure Set Point (psi)

20 5

50 14

65 15

75 16

85 18

Table C - 2. Pre-RC HHW secondary loop differential pressure set point control.

Outside Air Dry Bulb Temperature (°F) HHW Secondary Loop Differential Pressure Set Point (psi)

40 16

65 14

75 13

85 13

Table C - 3. Pre-RC dampers and return fan control sequence for AHUs HP 1-7

AHU # Condition Max OA

damper control Relief and return damper control

Min OA

damper control


Return fan speed

control

HP 1/2/3/6

OA T<65°F Loop control(MixT, DTSP)

if max OA damper>7psi, loop control (MinOAFlow, MinOAFlow.Setpoint)

on/off control; if supply fan is on, then on, else off

if supply fan is on, then on, else off

loop control(SA-$FixExhaust-$FixOffset)

OA T>65°F 1 psi 1 psi

HP 4



OA T>65°F

if return fan speed=4 HZ, Damper= 9 psi, if return fan speed>5.5 HZ, damper=1psi

1 psi

44

HP 5



OA T>65°F

if return fan speed<=4.2 HZ, Damper=12.8psi, if return fan speed>4.5 HZ, damper=1psi

1 psi

HP 7

OA T<65°F on/off control; if supply fan is on, then on (max damper position), else off (min damper position)

Loop control (MixT, DTSP)

/ OA T>65°F 1 psi

Table C - 4. Discharge air temperature set point schedule for AHUs HP 1-7


Discharge Air Temperature Setpoint (°F)

AHU HP1-6

55 65 65 63 70 60 80 58 90 55

AHU HP7

50 65 52 63 55 62 70 60 80 58 90 55

Table C - 5. Pre-RC Static pressure set point schedule for four AHUs.

Units

Outside Air Dry Bulb

Temperature (°F)

End Static Pressure ST2 Set Point (in.

W.C.)

Discharge Air Static Pressure ST1 Set Point

(in. W.C.)


AHU HP1

40 1

2.25 VFD speed=Min(loop

control (ST2, ST2 setpoint),loop control (ST1, ST1 setpoint))

65 1.2 75 1.3 85 1.5

AHU HP2

45 0.85

2.95 65 0.95 75 1 85 1.15

AHU HP3 40 0.8 2.0

45

65 0.9 75 1 85 1.1

AHU HP4

40 1.2

3.0 65 1.4 75 1.6 85 1.8

AHU HP5 / 1.35 3.0

AHU HP6

40 1

3.0 65 1.1 75 1.2 85 1.4

AHU HP7

40 0.9

2.0 65 1.1 75 1.25 85 1.4

Table C - 6. Pre-RC preheat set points for AHUs HP 1-6


Preheat Temperature Setpoint (°F)

HP 1/3/4

55 60 65 58 70 55 80 53 90 50

HP 2/5 / 50 HP 6 / 55

retro commissioning report - texas a&m university...the retro commissioning (rc) process...

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