The Rowland Hall HVAC retrofit project at the University of Utah upgraded the building's aging HVAC system to improve energy efficiency and occupant comfort. Key aspects of the retrofit included converting the constant air volume system to a variable air volume system, upgrading controls from pneumatic to digital, installing occupancy sensors and lab air control valves, and implementing a new approach to reduce airflow in unoccupied offices. These upgrades are estimated to save over 3.5 million kWh and 98,000 therms annually, reducing energy costs by $442,550 per year and paying back the $4.1 million project cost in under 7 years while lowering CO2 emissions.

1. Rowland Hall HVAC Retrofit Best Practice Award in HVAC Design and Retrofit 2011 Matt Gudorf Campus Energy Manager Nick Kimbell Project Manager

2. Overview Building Description Project Scope of Work Lab Air Control Valve Installation New Method for Occupancy Control of Office and Support Space Successfully completing a UC Investor Owned Utility partnership project Economic and Environmental Analysis

3. Rowland Hall Rowland Hall is a 6-story, approximately 232,000 square-foot, university laboratory building constructed in 1968. With a seismic retrofit in 2007. The building occupancy consists primarily of research laboratories, teaching laboratories, classrooms, and offices Fume Hood intensive with high hood density in multiple labs, there are 168 fume hoods in the building. 100% Outside Air, Dual Duct Second Largest Campus Energy Demand

4. Rowland HallHVAC Retrofit Project Asbestos Abatement Supply air duct cleaning Constant Air Volume to Variable Air Volume Pneumatic to Direct Digital Control Static Pressure Control Damper Installation Occupancy control of HVAC to offices at the zone level Lab Air Control Valve Upgrade Fume hood upgrades Sash Position Sensors Fume hood monitoring and alarm panel upgrade Zone Presence Sensor installation Test and Balance

6. Contractor required to carry the abatement subcontract to eliminate the possibility of the University being caught in the middle

8. When building load varies,shouldn’t the HVAC system follow? Constant Air Volume – Supply and Exhaust flow rate remains the same independent of: Fume hood sash position Thermal demand Occupancy Variable Air Volume – Supply and Exhaust changes depending on: Fume hood sash position Thermal Demand Occupancy

9. Constant Air Volume toVariable Air Volume VAV Constant Savings of 77,500 CFM Ventilation Rate (CFM) 270,000 CFM 192,857 CFM

10. Typical Lab Prior to Retrofit Constant Volume Phoenix Valves Constant Volume Dual Duct Mixing Boxes

11. Typical Lab Post Retrofit Variable Volume Phoenix Valves Mixing Boxes for temperature control and Phoenix Valves for flow control

12. Dual Duct to Phoenix Valve Connection for Lab Supply Air and Proper Set UP Duct static pressure must be equal to prevent backflow Temperature control of supply air New Mixing Boxes Control of flow (CFM) of supply air

13. Zone Presence Sensors Hood mounted occupancy controls provide savings when sashes are left open and unoccupied

14. CAV to VAV Lesson Learned Static Pressure to lab air control valves is higher than what should be supplied to a mixing box for an office. Supply duct

15. Pressure Requirements for Lab Air Control Valves and VAV Offices Would Result in Excessive Duct Noise 1.5” Static 1.5” Static Lab Supply Plenum Office Supply Plenum 1.5” Static Hot and Cold Deck Supply to Floor

16. Static Pressure Control Added toeach floor 1.5” Static .75” Static Lab Supply Plenum Office Supply Plenum Damper Position signal is sent to office exhaust valve to adjust office exhaust rate 1.5” Static Hot and Cold Deck Supply to Floor

18. Can perform complex sequences.

19. Can receive instructions from a master computer.

22. Occupied Mode To exhaust plenum TEC

23. Unoccupied Mode Previous Best Practice During periods of non occupancy temperature dead band would be increased to a wide range TEC If Unoccupied Heat to 60 Cool to 80

24. Unoccupied Mode Previous Best Practice When the room is unoccupied increase the dead band for temperature control to heat to 60 cool to 80. Room temperature would move to one extreme or the other and take too long to normalize when occupants returned to the space TEC 80 60 Time

25. Unoccupied Mode New method developed for Rowland Hall During periods of non occupancy Mixing Boxes are commanded to 3 modes TEC > 68 Mode 1 69-73 Mode 2 < 74 Mode 3

26. Unoccupied Mode 1Thermostat Less than 68°F Hot deck commanded to 10% open Air flow is not measured and no adjustments are made for duct pressure changes.

27. Unoccupied Mode 2Thermostat Between 68°-74° F Hot deck commanded to 5% open Air flow is not measured and no adjustments are made for duct pressure changes. Cold deck commanded to 5% open

28. Unoccupied Mode 3Thermostat Greater than 74°F Air flow is not measured and no adjustments are made for duct pressure changes. Cold deck commanded to 10% open

29. New Approach Provides Energy Savings and Improves Occupant Comfort 80 60 Time

30. SEP Partnership Steps

31. Implementation CostEnergy and Environmental SavingsPayback Project budget: $4,100,000 Incentive payment from the IOU’s totaling $922,000 Annual energy savings (kWh, therms): 3,486,767 kWh with a 640 kW demand reduction, reduced natural gas use by 98,000 therms Annual cost savings: $442,550 ($0.105 kWh demand charges included, $0.78 Therm) Annual cost to repay the bond: $306,564 $4,100,000−$922,000=$3,178,000 $3,178,000$442,550 = 7.18 Years CO2 emissions by 1,660 metric tons

32. Contribution to Sustainability Goals

36. Thank you for your time! QUESTIONS?? This concludes The American Institute of Architects Continuing Education Systems Program