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FY12 RCx (Completed)

Description

IN FY12 Retrocomissioning completed eight more buildings.

Background

Alice Campbell Alumni Center

The air handling units (AHUs) providing air conditioning were maintaining space conditions in offices and classrooms 24/7/365. The primary energy conservation method was scheduling AHU 3 and 4 off during non occupied hours and AHU 1 and 2 with static discharge setbacks. Occupancy sensors were installed in numerous rooms to control lighting and HVAC within the building. A payback analysis was performed and the results were less than a 2.5 year payback in utility savings. Discharge air temperature sensors were installed after the VAV reheats to achieve better control and comfort conditions. There was also humidity sensors installed in the return air on all four AHU’s and CO2 sensors installed in AHU’s 1 and 2 return duct. These can be utilized in the sequence of operation to achieve to achieve better operating and comfort conditions. To maintain comfort conditions, all thermostats were calibrated and the heating valves were inspected for proper operation. There are approximately 76 VAV’s in the building. It was found that the hot water radiation valves were operating backwards so the valves were closing when they should have been opening. All the valves were inspected and changed for proper operation.

Beckman Institute

Make up air for the wet labs was being supplied by the VAV dedicated to each room. The control strategy was varying the general lab exhaust leaving the room to maintain the room temperature. A previous project field adapted the fume hoods for variable volume operation. RCx changed the lab control to vary the supply air volume allowing the general exhaust to close when fume hoods were in operation. Hood controls were replaced to reduce exhaust air when sashes were closed. Fume hood system capacity increased avoiding capital investment for additional hoods desired by department. To improve space comfort conditions, all pneumatic thermostats and controllers associated with 354 VAVs were calibrated and / or replaced for proper operation. Each room was balanced for proper air flow, reducing HVAC energy use in most cases.

Campbell Hall and Richmond Studio

The department had the need to maintain space conditions in their broadcasting areas 24/7. Building air was provided to those critical spaces (25%) and the remaining offices (75%). Two CRAC units were available to care for that 25% at night, while allowing the building air to shut down. RCx worked with the facility managers to implement this idea. Now the air handling units (AHUs) are scheduled to shut down for 6-8 hours a day while the CRACs care for the space. To maintain comfort conditions, all 84 VAVs were balanced and the pneumatic heating strategy revised to allow the heat to come on ahead of increasing the air flow to wash the outside walls. reheat coil control valves were. Various VAV controllers and boxes were found nonoperational and were replaced, restoring thermal comfort and improving air flow control. Additional changes were scheduling a 24/7 rooftop unit, improving boilers & chillers, adding VFDs & CO2 sensor to single zone, increasing economizer possibilities and items affecting building pressure.

Engineering Hall

The air handling units (AHUs) were operating based on occupancy schedules upon arrival. These were expanded upon after consulting with the facility manager. The primary energy conservation measure was changing the VAV system operation. Original design called for the Max-Min-Max operation, where the air flow would reach maximum during the heating season. Since the building also has perimeter heat, the VAV pneumatic controls were modified to the conventional VAV Min-Max operation. This has allowed the building comfort to improve and reduce energy. The hydronic systems also required a large coordinated effort to replace over 35 control valves, many of which were located behind wood credenzas that had to be modified for permanent access. The building chilled water valve control also required adjustments to allow it to modulate to control flow; it was found wide open.

Illinois Sustainable Technology Center

The air handling units (AHUs) providing air conditioning were maintaining space conditions 24/7/365. The primary energy conservation method was scheduling the AHU serving the office areas to shut down for 12 hours a day. This was possible due to hot water radiation on the perimeter offices, which is controlled independently by the VAV units. The AHU’s serving the lab areas were scheduled for a set back during unoccupied times. This was achieved by removing the non-functional inlet vanes and installing VFD’s on the supply fans. The fan speed was reduce to a point where the labs were slightly negative. Building pressurization control was added to help maintain a positive building envelope. Control points were added and devices replaced to help achieve energy conservation and improve comfort conditions. All the VAV boxes in the office area were inspected for proper operation and calibrated. There was a reduction of air flow to the spaces, resulting in fan energy savings and improved comfort conditions.

Main Library

The air handling units (AHUs) providing air conditioning were maintaining space conditions 24/7/365. There were variable frequency drives installed on sixteen AHU’s that allow summer/winter and unoccupied setbacks. The primary energy conservation method was scheduling AHU’s off or with these setbacks during the unoccupied times. To maintain comfort conditions all thermostats were inspected and calibrated. There were numerous spaces that were found to be heating and cooling simultaneously. The addition of full DDC control to the AHU’s and heat exchangers gave more opportunity for energy saving measures and much improved comfort control. This gives the capability to perform temperature resets on discharge air based on the return air humidity and temperature. It also allowed the chilled water usage during the winter months to drop drastically by taking advantage of the economizer mode. The outside air dampers were replaced on AHU 4, 5 and 8 to eliminate stratification and prevent freezestat trips and chilled water usage.

Spurlock Museum

The air handling units (AHUs) providing air conditioning were maintaining space conditions in offices and the museum 24/7/365. The primary energy conservation method was scheduling AHU 3 off during non occupied hours and AHU 1 and 2 with static discharge setbacks. The existing control systems were replaced with new systems that have the capabilities viewing the control graphics. There were new humidity sensors installed in the return air on three of the four AHU’s and a CO2 sensor was installed on AHU 3. These can be utilized in the sequence of operation to achieve better operating and comfort conditions. To maintain comfort conditions, all thermostats were calibrated and the heating valves were inspected for proper operation. The variable air volume (VAV) boxes were also inspected and brought back to proper operation. There were nine inoperable VAV controllers found and replaced. There are approximately 16 VAV’s in the building. The existing building pressurization control was found not operating under control. This resulted in a negative building envelop which brought in un-conditioned outside air.

Water Survey Research Buildings

The air handling units (AHUs) providing air conditioning were maintaining space conditions in offices and labs 24/7/365. The primary energy conservation method was scheduling the AHU’s off during non-occupied hours. The existing pneumatic controls on the air handlers were replaced with a Siemens DDC system. Humidity sensors were installed in the return air on majority of the AHU’s. These can be utilized in the sequence of operation to achieve better operating and comfort conditions. The chilled water coils in the AHU’s were not sized for humidity control. They were designed for 60F discharge air set point. On warm humid days the chilled water valves are at 100% open and not meeting the 60F set point. The hot water radiation valves in Building 11 and Room 224 were operating backwards so the valves were opening when they should have been closing, which resulted in simultaneously heating and cooling. All the valves were inspected and changed for proper operation. The existing outside air dampers for buildings 1,4, 5 and 6 were in poor condition and leaking through. As a result, excessive unconditioned outside air is allowed which adds to the utility cost.

Conclusion

  • Alice Campbell Alumni Center, 39% savings
  • Beckman Institute, 15% savings
  • Campbell Hall and Richmond Studio, 32% savings
  • Engineering Hall, 39% savings
  • Illinois Sustainable Technology Center, 20% savings
  • Main Library, 38% savings
  • Spurlock Museum, 20% savings
  • Water Survey Research Buildings, 20% savings

Project Team

  • Project Leader:

    Karl Helmink

Themes

Project Location(s)

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