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FY13 RCx (Completed)
In FY13, Retrocommissioning was completed in three buildings.
Medical Sciences Building
Two of the AHUs have two wheels each, an enthalpy wheel and a sensible wheel with the heating and cooling coils between. Much careful engineering analysis and consulting with vendors and the original design engineer was required to optimize the energy wheels with the coils. Some control was being handled by the TAC system and some by the ALC system. A new and improved sequence was implemented and the units were checked for accurate measurements. Though control is still being performed by two systems, they now work harmoniously. RCx also lowered the amount of supply air required by the units. To maintain comfort conditions, all thermostats were calibrated and / or replaced and the heating valves were inspected for proper operation. There are approximately 128 VAV’s in the building. They were all inspected for proper operation, resulting in improved comfort.
Institute for Genomic Biology
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 setbacks and reducing CFM during non occupied times. Occupancy sensors were installed in the labs and conference rooms in the building, which controls the lighting and variable air volume boxes (VAV) for the spaces. This will reduce the CFM output of the AHUs when spaces go into unoccupied mode during a normal occupied time. There are approximately 300 VAV boxes in the building. Each box and thermostat was inspected for proper operation and calibrated. Discharge temperature sensors were installed after all the reheat coils for monitoring leaking reheat valves. There were numerous defective controllers and actuators replaced. Air handler 6, which supplies the office area, has an above the ceiling return. The large mechanical room adjacent to the space had not been properly seal and was open to the return path of AHU-6. This would pulled unconditioned air into the return in the winter and in the summer when the electrical vault exhaust fan was on it would pull the conditioned air into the mechanical room. The mechanical room was sealed from the conditioned space to prevent this from occurring. We also installed a VFD and a filtered intake for the electrical vault exhaust.
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 AHU’s off during non occupied hours. Occupancy sensors were installed on the south side to control lighting and variable air volume boxes (VAV) for spaces. Existing occupancy sensors that were for lighting control only on the north side were utilized to control VAV boxes as well. This will reduce the CFM output of the AHUs when spaces go into unoccupied mode during an a normal occupied time. There are approximately 65 VAV boxes total between the three variable volume AHUs. The boxes and thermostats were inspected for proper operation and calibrated or replaced as needed. The gym has three 20,000 CFM exhaust fans with no make-up air to the space or building. These were found to be running the majority of the time even if the gym was not in use. This was causing the building to become extremely negative and pulling unconditioned outside air in wherever it could. This is creating condensation and comfort issues and also creating additional energy expense from the HVAC and perimeter systems. DDC and VFDs were installed to control the exhaust fans on occupancy schedules.
- Medical Sciences Building, 25% savings
- Institute for Genomic Biology, 25% savings
- Huff Hall, 25% savings