Chilled Water System

Over the last several years, the University of Idaho has developed a central chilled water program that consists of 2 central plants where steam absorption and electric chillers of various sizes are located. This District Chilled Water Production and Distribution System resulted from a recommendation contained in a master plan for University of Idaho Energy Production and Distribution Systems developed by the University and engineering firm CH2M Hill in 1990/91 and updated in 1996.

Twenty-nine buildings in the central portion of campus are connected to the system. The system provides chilled water for process equipment cooling and environmental room conditioning in a reliable and cost effective manner. This has allowed elimination of many worn out and inefficient building chillers, and allows new buildings and major remodels of older buildings to be constructed without separate chillers.

Operation of the central chilled water system provides enhanced efficiency through load sharing and diversity by allowing operation of only the number and size of chillers required for the total cooling load, as opposed to running many building chillers at inefficient, partial load. In addition, the Univeresity sees a labor cost advantage related to the man-power required to operate and maintain fewer chillers in central locations versus the previous standard of operating and maintaining many chillers at diverse locations.

Additionally, the central chiller plant does not use HCFC refrigerants. The absorption machines do not use hydrocarbon refrigerant at all since the primary refrigerant is water. The only centrifugal chiller in the plant uses R-134 refrigerant. As older buildings with R-11 or R-12 chillers connect to the central plants and retire their chillers, it supports the phase-out of those refrigerants.

Chilled Water Tank

for efficient air conditioning

The 90-foot tall tank holds two million gallons of water and is being placed near the University golf course along Perimeter Drive More