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FY11 RCx (Completed)

Description

In FY11, the Retrocommissioning teams completed eight buildings. The Facilities & Services Retrocommissioning Team at the University of Illinois received the 2011 Illinois Governor’s Sustainability Award at a ceremony on Thursday, October 27, 2011. Established in 1987, this award has been presented to both public and private organizations that have achieved significant progress on projects designed to protect the environment and improve sustainability within the State of Illinois.

Background

Agricultural Egineering Sciences Building

The air handling units (AHUs) providing air conditioning were maintaining space conditions 24/7/365. The primary energy conservation method was scheduling the AHUs and bathroom exhaust to shut down for 12 hours a day. This was possible due to steam radiation on the perimeter and hot water fan coil heaters. To maintain comfort conditions, approximately 44 VAV boxes were reviewed, calibrated and balanced. Various VAV cross-flow sensors were found non-operational and were replaced, restoring thermal comfort and improving air flow control. It was found that the steam valve on the heat exchanger was leaking through. It was bad enough that the circulation pump was running 24/7/365 to help dissipate heat build up in the heat exchanger. A new valve as well as full DDC control was installed on the heat exchanger. New DDC web graphics were added to the controls system allowing the facility manager to observe the AHU systems from their desktop.

Armory

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 the AHUs off during non occupied hours. To maintain comfort conditions, all thermostats were calibrated and / or replaced and the heating valves were inspected for proper operation. There are approximately 118 VAV’s in the building. They were all inspected for proper operation and were calibrated and balanced which allow for the reduction of air to the spaces, resulting is fan energy savings without compromising comfort. Inlet vanes were removed on AHU 1, 2 and 3 and flow monitoring stations were removed on AHU 4 and 5. Removing these will eliminate any unnecessary pressure drops. The return and outside air duct for AHU 1 & 2 were modified to eliminate stratification. This will prevent nuisance freezestat trips and reduce chilled water use in winter.

Digital Computer Lab

Working with the duo-team of Greg Larson (College of Engineering) and Lori Beeson (CITES), multiple energy conservation methods were decided upon and methods to improve occupant comfort were discussed. During the process it became apparent that a larger capital project will be required at this facility in the very near future. The 26 air handling units (AHUs) providing air conditioning were maintaining space conditions 24/7/365. The primary energy conservation method was scheduling the 14 AHUs serving the office and lecture halls to shut down for 8-12 hours a day. For the complete pneumatically controlled AHUs time clocks were used for scheduling. The 7 heat exchanger systems were investigated. 4 of them were upgraded to DDC control, while the other 3 were improved pneumatically as they are scheduled for replacement. One of those 3 serves a two-pipe fan coil unit loop, one the perimeter heat loop and the final one the reheat coil loop. The outside air reference for the 3 was found to be high by 45 degrees and therefore providing extra heat by perimeter loop and not allowing cooling in the fan coil units. RCx calibrated the sensor and restored thermal comfort.

Foellinger Auditorium

The air handling units (AHUs) providing air conditioning were maintaining space conditions 24/7/365. The primary energy conservation method was scheduling the AHUs during after hours to a minimum setting. Web graphics were provided to the facility manager for HVAC system analysis from his desktop. Associated exhaust fans in the building were shut down during unoccupied hours. To maintain comfort conditions, all thermostats were calibrated and / or replaced and the VAV’s were inspected for proper operation. There are ten VAV’s in the building and all their controllers needed replaced. It was found that a 14” VAV branch duct came lose and was blowing freely above the ceiling. The ten VAV boxes were calibrated and balanced which allow for the reduction of air to the spaces, resulting is fan energy savings without compromising comfort. Inlet vanes and flow monitoring stations were removed from the supply and return duct of AHU1 which they were creating an excessive pressure drop.

Foreign Languages Building

The air handling units (AHUs) providing air conditioning were maintaining space conditions 24/7/365. The primary energy conservation method was scheduling the AHUs serving the office areas to shut down for 10 to 12 hours a day and some on the weekends. This was possible due to the induction unit s on the perimeter acting as convectors. Building occupants complained about the staleness of the air. Upon RCx investigation of the AHUs, it was noted that outside air fans were operating, but air was NOT being introduced into any of the AHUs since dampers were closed! Therefore, the air had been recirculating for an unknown period of years. Dampers and actuators were repaired and the outside air was improved, even though this led to an increase in utility costs and lengthening of payback. The induction units were also reviewed for cleanliness and CFM quantities. A capital project is to follow that will replace all of the dual duct boxes with VAV dual duct boxes, replace the outdoor air fan and relief fans, and upgrade the remaining (3) AHUs to DDC control. Following through on these recommendations will reduce energy and costs, improving payback.

Grainger Engineering Library

The air handling units (AHUs) providing air conditioning were maintaining space conditions 24/7/365. The primary energy conservation method was to visit each VAV box in the building and re-balance the system to its’ current requirements. This allowed a reduction in the VAV minimums, therefore reducing unnecessary reheat through the building. The other issue addressed by this box-by-box visit was building pressurization issues. Currently, the building will maintain a slight positive pressurization during all modes of operation, which had been an issue for several years. Leaking reheat valves were replaced, as well as faulty pneumatic controllers. The addition of DDC controls to both heat exchanger systems, as well as VFD’s to the radiation system, gave more opportunities for savings. Temperature resets were implemented on both systems based on return water temperature. The radiation system had a DP transmitter installed to deliver only the required amount of water to the system, instead of pumping water unnecessarily.

Henry Administration Building

Most of the air handling units (AHUs) providing air conditioning were maintaining space conditions 24/7/365. The primary energy conservation method was scheduling the AHUs serving the office areas to shut down for 12 hours a day and weekends. Web graphics were provided to the facility manager for HVAC system analysis from his desktop. Associated exhaust fans in the building were shut down during unoccupied hours. To improve comfort conditions, various VAV controllers were found non -operational and were replaced, allowing the reduction of air to spaces and saving fan energy without compromising space comfort. Automatic steam valves were found in the perimeter and reheat systems not connected to the control system. These were connected up to the DDC system to allow the steam to be controlled and / or shut off when conditions did not merit it.

Physcial Plant Services Building

The air handling units (AHUs) providing air conditioning were maintaining space conditions 24/7/365. The primary energy conservation method was scheduling the AHUs serving the office areas to shut down for 12 hours a day. This was possible due to steam radiation on the perimeter offices, which is controlled independently of the VAV units. To maintain comfort conditions, reheat coil control valves were checked for leakage rates. Approximately 40 VAV boxes were reviewed, calibrated and balanced. Various VAV controllers were found non-operational and were replaced, restoring thermal comfort and improving minimum air flow control. As directed by Shop Foreman, various heating only AHUs in the shop areas were repaired and serviced after many years of neglect. The field techs assisted in sharing knowledge with the foremen about how the AHUs operate to help improve comfort year-round.

 

Conclusion

  • Agricultural Engineering Sciences Building, 11% savings
  • Armory, 36% savings
  • Digital Computer Lab, 39% savings
  • Foellinger Auditorium, 8% savings
  • Foreign Languages Building, 42% savings
  • Grainger Engineering Library, 14% savings
  • Henry Administration Building, 17% savings
  • Physical Plant Services Building, 19% savings

Project Team

  • Project Leader:

    Karl Helmink

Themes

Project Location(s)

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