The cooling requirements for all the facilities located in the Greater Campus Area (GCA) are met through the supply of chilled water from the Utilities Chilled Water (CHW) System. This system consists of a CHW distribution system and three main facilities: the Cooling Plant (CP), Thermal Energy Storage System (TESS), and the Cooling Plant on Campus (CPOC). The CHW is used for air-conditioning, cooling medical equipment and computers, and cooling for the on-campus power generation located in the Heating Plant.
The CHW system operates as a constant temperature differential and a variable volume system. Hydraulic isolation between the CHW producing facilities and the buildings occurs via a system of CHW bridges.
The Cooling Plant is located on the south bank of the North Saskatchewan River. It has 26,000 tons of cooling capacity. The plant was built in phases from 1968 to 1983.
In order to respond to load demands as efficiently as possible, the plant has a number of chillers varying in size from 2,000 to 3,500 tons. All of the machines use electric driven centrifugal compressors. Water from the North Saskatchewan River is used for condensing purposes. Using river water as condenser water makes this plant more efficient as compared to a plant using evaporative cooling towers for condenser water cooling.
During the winter months, the plant operates in a free-cooling mode where chilled water is produced without using the compressors because of the very low river water temperature. This significantly reduces the cost of CHW production because the electric driven compressors do not have to be operated to produce the CHW.
A 60,000 ton-hour Thermal Energy Storage System was placed into operation in the summer of 2005. The TESS has the equivalent peak capacity of a 5,000-ton chiller. In addition to adding capacity to the CHW system, it is used in an energy cost-reduction strategy. CHW for TESS is produced during off-peak hours when power prices are lower and CHW is discharged from TESS during on-peak hours when power prices are higher.
A new 10,000-ton CHW plant was brought online in 2011. This plant is located near the Edmonton Clinic Health Academy. It uses traditional evaporative cooling towers to cool the condenser water. It is used as a peaking plant from mid-May to mid-September.
Chilled Water capacity:
- Peak CHW system flow: 13,000 m3/h
- Winter free cooling flow: 1,400 m3/h
- Maximum system capacity: 41,000 tons
- Annual CHW producton volume (2014): 25,000,000 m3