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AUDIT PHASE RETROCOMMISSIONING REPORT

MARCH 16, 2017

Contact: Mike Barnett, PE

HGA Phone: 608-554-5339

E-mail: mbarnett@hga.com

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EXECUTIVE SUMMARY

During the fall and winter of 2016, HGA performed a retrocommissioning energy audit as part of the Focus on Energy retrocommissioning process at . The measures identified included scheduling and optimization of heating, ventilating, and air conditioning equipment such as rooftop units and the VAV boxes.

presented some unique challenges for retrocommissioning including limited building documentation, extremely varied zone schedules and a building made of a conglomerate of other buildings and systems both old and new. Regardless of the challenges, there were some excellent retrocommissioning measures identified that have quick paybacks and significant energy savings. The table below summarizes the estimated savings associated with all the identified measures

Measure Savings Summary

Amount Unit % of

annual bill

Est. Electricity Savings 94,870 kWh/yr 11%

Est. Steam Savings 13,417 Therms/yr 25%

Est. Cost Savings $20,971 $/yr 14%

Cost of Implementation $30,000 $

Simple Payback 1.4 years

Est. Total Incentive

$3,795 $

Incentive not

available for steam

savings Simple payback after

incentive 1.3 years

Details of the measures are located in the body of the report. Next steps would be as follows:

• Audit review meeting: Review , fine tune and select measures with the team

• Develop implementation contract with HGA

• HGA develops detailed implementation narratives for contractors

• Confirm contractor pricing

• Implement measures

• Verify measures, adjust as necessary for long term persistence

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TABLE OF CONTENTS

EXECUTIVE SUMMARY ........................................................................................................................................... 2

INTRODUCTION ..................................................................................................................................................... 4

Building HVAC Systems ......................................................................................................................................... 4

UTILITY ENERGY-USE ANALYSIS ............................................................................................................................. 7

RETROCOMMISSIONING MEASURES .................................................................................................................... 12

M1- FIX RTU-3 SCHEDULING COMMUNICATION ISSUE ....................................................................................................... 14 M2- REPAIR AHU-1 ZONE DAMPERS AND ACTUATORS ........................................................................................................ 15 M3- IMPLEMENT OCC SENSOR CONTROL OF VAV BOXES ASSOCIATED WITH RTU-2 .................................................................. 16 M4- IMPLEMENT VAV SCHEDULING FOR VACANT SPACES ASSOCIATED WITH RTU-3 ................................................................. 17 M5- IMPLEMENT OCCUPANCY CONTROLS ON RTU-4 .......................................................................................................... 18 M6- IMPLEMENT DUAL MAX VAV CONTROL FOR HEATING ON RTU-2 VAVS ........................................................................... 19 M7- REVISE RTU-4 PROGRAMMING SO THAT UNIT DOES NOT GO TO CONSTANT VOLUME MODE ABOVE 68F. ............................... 19 M8- IMPLEMENT DUCT STATIC AND TEMPERATURE RESET ON RTU-2 AND 3 ............................................................................ 20

ADDITIONAL MEASURES OUTSIDE FOCUS RCX SCOPE .......................................................................................... 21

Additional Measures .......................................................................................................................................... 21 Future Measures for Consideration ................................................................................................................... 23

APPENDIX A- HVAC FLOORPLANS ........................................................................................................................ 26

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INTRODUCTION

The Education Center is part of the campus. The 127,000 sq-ft building houses a wide variety of technical training programs including appliance repair, carpentry, bricklaying and masonry, plumbing, upholstery, hydraulics and drafting. In addition to programs, the building also rents space to the Centro Hispano of . In addition to the occupied space, there is a fair amount of vacant space in the building. For a complete layout of the building, see the floor plans later in this section.

Prior to the building being used as an education center, it housed the Enterprise Center and Incubator, which was designed to provide low cost rent to help launch new businesses and create jobs. Prior to the Enterprise Center, the building was used primarily for manufacturing activities.

HGA was hired by to complete the audit phase of a retrocommissioning project in the fall of 2016. This report details the findings of this RCx investigation and lays the foundation for the retrocommissioning implementation phase.

The project is currently enrolled in the Focus on Energy Retrocommissioning Program, which provides incentives for energy savings achieved through retrocommissioning measure implementation.

This retrocommissioning project was intended to build of the information provided in the Level 2 energy audit provided by in early 2016, and provide detailed low cost energy efficiency measures than can be implemented through the Focus on Energy Retrocommissioning program.

BUILDING HVAC SYSTEMS

Due to the buildings various remodels and updates, there are numerous sets of remodel drawings for the building. Key documentation such as testing, adjusting and balancing reports and control drawings were not located. HVAC floorplans showing RTU and VAV zoning is included in the appendix.

The building is heated and cooled primarily by 5 roof top unit with DX cooling and gas heat. There is a combination of single zone RTU’s as well as RTU’s that serve variable air volume (VAV) boxes. The VAV boxes are a combination of hot water and steam coil VAV’s. There is 1 indoor AHU that serves the 4th floor. This is a hot deck/cold deck unit with steam heating and a dedicated condensing unit serving the cooling coil.

Steam for the building is provided by a nearby plant. The steam condensate goes directly to drain at a variety of locations throughout the building.

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Air Distribution Systems: RTU and AHU Summary

Year Tag Area Served Supply

Air CFM Outside Air CFM

Cooling Heating Level

served Controls

Unit Location

2014 RTU-1 Level 2 (lobby and admin

offices) and ≈7,500

DX- 3compressors

Gas 2,3 Stand alone stat

Roof above lobby

2012 RTU-2 Appliance, Plumbing,

Drafting, Comp lab and Hydraulics

14,095 1,840 DX Gas 5 Packaged with BAS interface

Roof above level 5 east

2013 RTU-3 Level 4 OWED and Level 5

Upholstery ≈12,500

DX- 4compressors

Gas 4,5 Packaged with BAS interface

Roof above level 2 west

2013 RTU-4 Masonry and Pathways 9,300 1,860 DX- 3

compressors Gas 1

Packaged with BAS interface

Roof above level 2 west

2015 RTU-5 Employee break room ≈4,000 DX- 2

compressors Gas 4

Stand alone stat

Roof above level 4 center

1997 AHU-1 Level 4 east (Second floor) 15,300 DX-3

compressors Steam 4 BAS

Level 4 mech room

2017 RTU-1(2)

Carpentry Lab Steam Gas 1 BAS Loading Dock

Roof

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Air Distribution Systems: Exhaust Fan Summary

Year Tag Area Served Exhaust

CFM Associated AHU/RTU

Level served Controls

Unit Location

2012 PRV-1 Ground, 2nd and 3rd toilet

rooms (level 1,4,5) 2,025 1,4,5 BAS Level 5 Roof

2012 EF-1 Appliance Service Fume

Hood 400 5 ? Level 5 Roof?

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UTILITY ENERGY-USE ANALYSIS

The utility data for electricity, gas and steam is summarized in the pages below. Based on the building type and energy usage, the building uses less energy than a typical building of its size. However, a more detailed review of the building would indicate that many portions of the building are used intermittingly, and a portion of the building is not currently occupied. Based on these observations, and HGA felt that there would be worthwhile retrocommissioning measure that could be identified and implemented through the Focus on Energy RCx program.

The table below summarizes the energy consumption. There is limited benchmarking data available for college, university and tech school energy consumption. However, when comparing

to similar K-12 facilities and office buildings, the source energy consumption is in-line with the average energy consuming buildings. These findings are inline with the conclusion drawn from the Energy Assessment Report completed in 2016.

Figure 1- Energy Performance Metrics

Figure 2- Annual Utility Use Breakdown

(Jan 2015-Dec 2015)

Post-RCx Forecast

Site EUI [kBtu/SF-yr]

66 56

Source EUI [kBtu/SF-yr]

136 109

Annual Utility Costs ($)

$145,000 $130,000

Annual Utility Costs ($/ft2) [127,000ft2]

$1.15 $1.02

Electricity (kWh/yr)

Natural Gas (therms/yr)

Steam (Therms/yr)

Cost ($/yr)

(2015) 856,000 18,833 42,745 $118,141

RCx Project Forecasted Savings

100,000 0 8,400 $15,000

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Figure 3- Clinic Electricity Consumption

The figure above includes 3 years of monthly electric consumption. The electric consumption is consistent with mechanical cooling in the summer, and gas for heating and reheat in the winter. The summer spike from mechanical cooling is slightly less than expected. This may be due to reduced cooling loads achieved by turning off the steam in the summer and eliminating VAV reheat and the subsequent re-cooling of the return air. However, turning off reheat in the summer results in over-cooling spaces and limited control of space humidity. This will be reviewed within the measure section of the report.

0

10,000

20,000

30,000

40,000

50,000

60,000

70,000

80,000

90,000

100,000

kW-h

r

Electricity Consumption Profile

2015

2014

2013

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Figure 4- Natural Gas Consumption

The trend of natural gas consumption, seen in the figure above, follows a predictable distribution, where there is a clear peak during peak-heating season in the winter with a drop-off in the summer months. Natural gas is used in the roof top unit for heating and also used for domestic water heating.

0

500

1,000

1,500

2,000

2,500

3,000

3,500

4,000

4,500

5,000

The

rms

Gas Consumption Profile

2015

2014

2013

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Figure 5- Steam Consumption

Steam is used in the building directly for VAV coils and AHU-1 heating coil, and also used through a heat exchanger to generate hot water for additional VAV reheat coils. It appears that the steam is shut off in the summer months. It was not clear if steam is not produced by in the summer, or if

physically shuts off the steam supply. When steam is shut off in the summer, there is no VAV reheat throughout the facility.

0

1000

2000

3000

4000

5000

6000

7000

8000

9000

The

rms

Steam Consumption Profile

2015

2014

2013

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The figure below shows that 59% of utility costs is electricity. From a retrocommissioning perspective, the biggest opportunity for saving electric energy is fan power reduction at the roof top units. The measure section will get into specific opportunities for electricity savings. The remaining 41% of the building’s utility cost can be attributed to gas and steam consumption.

Figure 6- Utility Costs by End-Use

Figure 6- Gas and Steam Cost Comparison

Figure 6 shows the costs difference per unit energy between steam and natural gas. Based on historical data steam is typically 30-40% more expensive than natural gas. There are some opportunities to fuel switch to natural gas at the roof top units, rather than the VAVs. These opportunities will be further outlined in the measures section.

electric$70,127

59%

gas $21,152

18%

steam$26,862

23%

Utility Cost Breakdown

electric

gas

steam

Natural Gas Cost / Therm

Steam Cost / Therm

Natural gas cost savings per therm

(2015) $0.78 $1.12 30%

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RETROCOMMISSIONING MEASURES

Measure Title Annual

Energy Cost Savings

Estimated Implementation

Cost

Payback (years)

1 RTU-3 Scheduled, but running 24/7 due to faulty communication $4,313 $1,000 0.2

2 Repair AHU-1 zone dampers and actuators to reduce overheating of spaces $2,629 $2,500 1.0

3 Implement occ sensor control of VAV boxes associated with RTU-2 $3,649 $10,000 2.7

4 Implement VAV scheduling for vacant spaces associated with RTU-3 $1,634 $1,500 0.9

5 Implement occupancy controls on RTU-4 $490 $5,000 10.2

6 Implement dual max VAV logic on RTU-2 VAVs TBD TBD TBD

7 Revise RTU-4 programming so that unit does not go to constant volume mode above 68F.

$309 $500 1.6

8 Implement temperature and duct static pressure reset on RTU-2, 3, 4 $1,446 $1,500 1.0

9 Additional Summer Modifications? TBD TBD TBD

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Measure Title Annual

Energy Cost Savings

Estimated Implementation

Cost

Payback (years)

Totals $14,471 $22,000 1.5

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M1- FIX RTU-3 SCHEDULING COMMUNICATION ISSUE

RTU-3 is scheduled through the JCI metasys building automation system (BAS), but the unit is

not shutting off at night. There appears to be an issue with the communication between the

BAS and the RTU factory controller.

Working with Masters Building Solutions, the equipment rep, this issue can be troubleshot and

resolved.

RTU-3 Scheduled Through Metasys but unit is not responding

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M2- REPAIR AHU-1 ZONE DAMPERS AND ACTUATORS

AHU-1 is a hot deck/cold deck unit. The cold deck supply temperature is 55°F and the hot deck

supply temperature is 100°F. When testing the unit it was observed that 6 of the 9 zone

dampers were not controlling properly, and resulted in overheating the supply temperature

and overheating the spaces.

mechanic or a contractor would need to open up AHU-1 and determine why the zone

dampers are not controlling properly. This could be an issue physically with the zone dampers

or with the damper actuators.

AHU-1 Hot Deck-Cold Deck Unit Showing the Various Zone Damper Actuators

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M3- IMPLEMENT OCC SENSOR CONTROL OF VAV BOXES ASSOCIATED WITH RTU-2

RTU-2 serves a large portion of the 5th floor, including 14 VAV boxes. The unit is scheduled to

run 6a-9p Monday through Saturday. However, most of the spaces/VAVs served by the unit

are only utilized a few hours per day. HGA proposes to tie into the existing lighting occ sensors

and allow the VAV's to go into a stand by mode when the spaces are vacant. This measure will

allow the VAV's to maintain space temps, but close the box when space temps are satisfied and

the space is vacant. This will reduce reheat and fan energy.

As an alternative to occ sensors, VAVs could be scheduled to coincide with the class schedule. If the

schedule was omitted, pressing the occupied override button on the stat would put the unit back into

the occupied mode. This method is more labor intensive, but more economical than an occupancy tie

into to the VAVs.

RTU-2 typically runs at 100% supply fan speed. Therefore, implementing VAV scheduling has excellent

opportunity for savings.

RTU-2 Serving Level 5 Spaces

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M4- IMPLEMENT VAV SCHEDULING FOR VACANT SPACES ASSOCIATED WITH RTU-3

RTU-3 serves the west side of both the 4th and 5th floors. The unit is scheduled to run 6a-5p Monday

through Saturday. However, most of the spaces/VAVs served by the unit are vacant spaces that are not

currently being used. HGA proposes to implement VAV scheduling for the vacant spaces. The VAVs will

conintue to maintain space temperature between 70-74F, but when the space temperature is between

70-74F, the VAV box will be allowed to close. The occupancy override on the thermostat will allow the

VAV box to transistion from an occupied standby mode to an occupied mode. This measure will reduce

reheat and fan energy. As an alternate, we could look at adding some occupancy sensors tied to the

VAVs for some of these spaces that might be actively being used.

RTU-3

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M5- IMPLEMENT OCCUPANCY CONTROLS ON RTU-4

RTU-4 serves the basement masonry lab and the Pathways to Construction lab and classroom space.

The unit is scheduled to run 6a-8p Monday through Friday, and Saturday 6a-4p. However, there are

many hours were these spaces are not being utilized. HGA proposes to tie into the existing lighting occ

sensors in the Pathway to construction lab, and add occ sensors to the masonry lab (or utilize the

occupant override function on the thermostats to allow the VAV's to go into a stand by mode when the

spaces are vacant. This will allow the VAV's to maintain space temps, but close the box when space

temps are satisfied and the space is vacant. Alternatively, the RTU could be shut down when all the

spaces are vacant and maintain occupied setback temperatures. This will reduce reheat and fan energy.

Summer control should be further discussed as it may be advantageous to have a separate control

sequence for the RTU in the summer if the spaces are vacant, such that the unit would only cycle on to

maintain space temperature and reasonable humidity.

RTU-4

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M6- IMPLEMENT DUAL MAX VAV CONTROL FOR HEATING ON RTU-2 VAVS

RTU-2 VAVs utilize a single heating air flow. When the VAV requires heat, the box goes to its heating

airflow. The current heating airflows are not consistent with the design values. It is likely that the

design flows were not adequate to heat the spaces, or that the steam coil were not controllable at lower

airflow. Assuming that we can control the steam coils at the lower heating flow, HGA proposed that we

implement a min and max heating flow control strategy. When box needs heat, will start and min

heating and modulate toward max heating airflow. This will reduce the amount of reheat required and

prevent the constant switching between heating and cooling mode.

M7- REVISE RTU-4 PROGRAMMING SO THAT UNIT DOES NOT GO TO CONSTANT VOLUME

MODE ABOVE 68F.

When the OA temp is greater than 68F, all the min cooling cfm setpoints reset from their design min to

their design max. This was done to avoid having low flow conditions in cooling mode, prior to the

additional build out associated with the RTU-4 spaces served. It appears that after these spaces were

building out, this control logic was never removed. Additionally, the unit has a bypass damper that can

be used to maintain min airflow and avoid unneeded reheat at the VAV level.

HGA proposes that this logic is modified to reduce the min cooling flow setpoints as close to possible to

their design values prior to having dx airflow issues.

This will also help with preventing the overcooling of these spaces, if the reheat is continued to be

disabled in the summer months.

Alternatively, this measure can be adjusted such that in the summer the unit will run in a auto fan mode,

such that the unit will only come on occasionally to maintain space temperature, then cycle off. This

would work if the spaces are not actively used in the summer.

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M8- IMPLEMENT DUCT STATIC AND TEMPERATURE RESET ON RTU-2 AND 3

HGA proposes implement a duct static pressure and discharge air temperature reset for RTU's 2 and 3.

Currently both the duct static pressure setpoints and discharge air temperature are fixed on both these

units.

On RTU-2, the supply fan runs at 100% all the time with no single VAV more than 70% open. By

resetting the duct static pressure off the VAV damper position, the fan power would be reduced.

Additionally, resetting the DAT based on box cooling load, would allow the DAT set point to increase so

that there is not excess reheat at the VAV level, when boxes are all in heating mode.

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ADDITIONAL MEASURES OUTSIDE FOCUS RCX SCOPE

ADDITIONAL MEASURES

These are measures that would not be incentive through the Focus on Energy RCx program, but would be worthwhile to complete during the RCx implementation.

Steam Trap Survey and Repair

There are likely around 50 steam traps in the building. There is no record of any steam trap survey in recent time. Based on the lack of maintenance related to the steam traps, HGA would estimate the around 15% of the steam traps are failed open.

It is recommended that a steam contractor survey the traps and repair or replace faulty steam traps. There may be incentives through Focus on Energy for this work. Please consult with your Focus on Energy rep.

Steam Piping Pressure Reducing Station from Main Supply

Steam savings

(therms)

Annual Savings ($/yr)

Measure Cost ($/yr)

Simple Payback

Steam Trap Survey and Repair

6,400 $6,400 $7,500 1.2 years

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Discontinue Summer Steam Shutdown

In the past few years the steam appears to be shut down to the building in the months of June, July and

August. Because most of the building is served by VAV’s with reheat, the lack of reheat in summer

results in overcooling of spaces and limited dehumidification control. If is still supplying

steam in the summer months, HGA would recommend that the steam system be enabled in the summer

until the outside air temperature is greater than 85°F. This could be programmed through the Metasys

building automation.

There will be a steam penalty associated with this measure, but the occupant comfort will be greatly

improved. Verification of steam trap functionality and steam control valve functionality on terminal

units will be of increased importance if the steam is on in the summer months.

Implement Unoccupied Heating and Cooling Programming for RTU’s

Currently, when the RTU’s are off on schedule, the units will remain off regardless of the space temperature. This results in the spaces having to recover from a large setback on start-up. If occupant comfort is impacted by the length of the warm-up period, HGA recommends that the RTU’s operate in a night heat/cool mode to maintain the space temperatures at unoccupied levels, such as 65°F and 80°F.

The unoccupied night heat mode also provides some insurance of freezing issues with the spaces. It is somewhat surprising that the building has gone this long with no nigh heating RTU control.

There would be a small energy penalty associated with this measure. However, the schedules could likely be adjusted such that the occupied run time is reduced. Therefore, there would be no net impact to energy consumption.

Steam savings

(therms)

Annual Savings ($/yr)

Measure Cost ($/yr)

Simple Payback

Keep Steam on in Summer -1,500 -$1,500 $500 N/A

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FUTURE MEASURES FOR CONSIDERATION

Recover Steam Condensate

There is no condensate return back to the power plant that generates the steam. All steam condensate

goes directly to drain after flowing through the steam traps. This results in 190°F going down the drain.

There is a substantial amount of heat in the condensate that is wasted by going directly to drain.

An ideal use of condensate water would be to preheat domestic hot water. However, there are

numerous water heaters scattered throughout the facility such that piping the condensate to the

various water heaters becomes prohibitively expensive. Additionally, the building domestic hot water

heating load is relatively small when compared to the waste heat from the condensate.

An alternative source to capture the condensate waste heat would be to preheat the return side of the

hydronic hot water loop. To improve the temperature differential between the condensate and the

hydronic hot water return, it would be beneficial to reset the supply water temperature based on the

outdoor air temperature. Currently, the supply water temperature is maintained at 180°F year round.

This system would require a pump, heat exchanger and controls.

Steam Condensate Piping Going to Drain

Steam savings

(therms)

Annual Savings ($/yr)

Measure Cost ($/yr)

Simple Payback

Condensate Heat Recovery 1,470 $1,470 $35,000 24 years

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Install Condensing Boiler and Replace Steam Terminal Unit with Hot Water Units

District steam is roughly 30-40% more expensive than gas at . Long term it would be

more economical to produce hot water on-site with a natural gas boiler. This would require that all the

steam terminal units, such as the VAV’s on the 5th floor, are replaced with hot water coils. There is

significant expense associated with this measure and the costs and savings are beyond the scope of this

report. If the building ever plans to undergo extensive remodeling, it would be worthwhile to revisit this

measure.

Assuming a 30% cost savings off the current steam costs, there would be an approximate $8,000 annual

cost savings.

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Replace AHU-1 with a VAV Air Handler and Install VAV’s Serving Each Zone

AHU-1 is a 15,000 cfm constant volume hot deck / cold deck air handler. The fan is constant volume

with no ability for turn down. A VAV AHU would enable the supply fan to modulate to meet the space

loads. The unit has a 20hp fan. Estimated fan savings from this replacement would be approximately

35,000 kW-hr per year. There would also be a few KW of peak savings.

Another issue with AHU-1 is that there is tremendous noise emanating from the return grille into the

student lounge space. Decibel levels were not measured, but the noise is significant and impacts the

ability to carry on conversation when seated near the return grille opening. Any replacement or

upgrading of AHU-1 should address the return air noise issues through an addition of a sound attenuator

or other duct work modification to reduce the noise transmission through the return ductwork.

This measure would only make sense economically if the AHU-1 was being replaced. Completing this

measure purely for the efficiency benefit would not be cost effective. The replacement of AHU-1 with a

VAV unit could be accomplished 2 ways:

• Replace existing AHU-1 with similar built up VAV unit and install new condensing unit on the

roof

• Alternately, a lower cost option may be to install a VAV roof top unit in the current location of

the condensing unit, then route the supply and return ductwork through the mechanical space.

The redesign of this unit is outside of the scope of the energy audit. But it would be worthwhile to

explore these options, prior to the replacement of the existing condensing unit. Scope of work would

include the following items:

• Replace existing hot deck-cold deck unit with VAV AHU and condensing unit, or VAV roof top

unit

• Install VAV boxes in existing ductwork serving the same spaces as the current zone dampers.

There are approximately 10 zones that would require VAV boxes with reheat.

• Pipe hot water to the new VAV reheat coils

• Associated controls for new AHU and VAV boxes

HGA estimates that this project could cost upwards of $200,000 due to the extensive refit required for

the VAV reheat piping and all the work required to remove the existing unit.

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APPENDIX A- HVAC FLOORPLANS