Hazelton Secondary School is located in northern British Columbia in an area not serviced by the natural gas grid connection. The original heating system relied on propane-fired gas boilers. A geoexchange system was implemented to mitigate high propane energy consumption costs and to significantly reduce carbon emissions resulting from facility heating.
Geoexchange heat pumps are most efficient when they deliver heat at lower temperatures (for example 50°C or less). The original legacy system was designed to distribute heat from the propane boilers at more than 80°C. The retrofit was originally planned to upgrade the heat distribution system to accommodate the ideal 50°C heat pump delivery temperatures. Budget constraints shifted the design approach to adopt a higher temperature heat pump system capable of delivering heat at 70°C, allowing the original heat distribution system to be retained. Although this system is inherently not as energy efficient as the original proposed design would have been, it was a cost effective compromise approach that nevertheless resulted in significant propane and carbon emission savings. With the high temperature heat pumps, the existing propane boilers continue to operate in the coldest weather when the most extreme heating loads occur.
A vertical borehole style geothermal ground heat exchanger (GHX) system installed deep into the underlying bedrock was installed in 2017, while the geothermal heat pumps and mechanical heating plant modifications were installed in 2018. The system was commissioned in 2019.