View more information at the US Department of Energy's Better Buildings website.
CCAC pursued a bond-funded guaranteed savings project specifying the following measures:
- New boilers
- New electric chillers
- Conversion of the exterior lighting system to LED fixtures
- Retrocommissioning of the unit ventilators and other HVAC system components that were remaining in place.
Firms responding to the RFP were welcome to propose additional measures, and the firm chosen to complete the project proposed some additional lighting retrofits, replacement of a smaller rooftop chiller, and plumbing retrofits to low-flow fixtures. Water savings were enhanced by the reduction in necessary heat rejection of the electric chillers over the absorbers, thus lessening the amount of water that needed to go to the cooling tower.
This was the first time CCAC had pursued guaranteed savings performance contract, and the project progressed very well. One of the main anticipated problems was keeping the building in operation. Classes are in session year-round, so long-term shutdowns are difficult, if not impossible. The existing chillers and boilers were nearing the end of their useful life, and were not expected to make it through another cooling season. However, the contractor was able to obtain and install one new chiller that kept the campus up and running, and clever operations by the physical plant staff kept the building comfortable through the beginning of the cooling season – cool outside air was brought into the building at night to pre-cool space, thus avoiding the expense of a temporary chiller.
Even though electric chillers were added to replace the absorbers, the electricity consumption at the building decreased because of the lighting retrofits, installation of air eliminator units in the piping systems, and new variable-speed pumping systems. The reduction in gas usage was so large that the gas company checked their meter for errors several times.
The retro-commissioning of the unit ventilators revealed problems in 43 percent of the units, including some malfunctioning freeze stats.