Justice Institute of BC
New Westminster, BC
The 19-year-old chiller supplying cooling to the New Westminster Campus of the Justice Institute of BC was suffering from aging systems and technology. It was struggling to obtain the design capacity on peak cooling days and used a banned CFC refrigerant. Its water pump was undersized could not be serviced without shutting down the cooling system as there was no redundancy.
The old chiller was an air-cooled, screw-type, dual compressor unit (100 + 85 tonnes) with a designed chilled water flow of 300 US GPM, and a full load power draw of 225kW. The chiller had a nominal cooling capacity of 180 tonnes.
Prism’s life cycle analysis indicated the most cost-effective option for upgrading the chiller was a high-efficiency model, and the VFD option was also attractive due to its relative cost-effectiveness and the anticipated extra five-year service life. We selected a model with two variable speed screw-type compressors, 332 GPM design chilled water flow, 206kW, with 180 tonnes capacity.
This produced a system which was 8% more efficient at full load with higher efficiencies at part load as it is a VSD chiller. The increased pumping capacity allowed for effective distribution of cooling to the building’s air systems and now the chiller operates well under peak design conditions.