Field study of cooling performance of two ground-source heat pumps in Canadian single-family houses

•Variable speed compressor significantly improved the performance of the GSHPs.•Seasonal COP of GSHP and GSHP system are 12.9 and 11.0, respectively.•Operating cost of the GSHP is less than traditional ASHP by up to 66%. This paper is the first part of a two-part study of the performance of ground–source heat pumps (GSHPs) in single–family detached houses in Canada. In this paper, the cooling performance of two 4–ton (14 kW) vertical closed–loop water–to–air GSHP systems installed in two single–family detached houses in Innisfil (80 km north of Toronto, Canada) is monitored, analyzed and evaluated over one cooling season. Results show that the seasonal coefficient of performance of heat pump (COPhp) and GSHP system (COPsys) are 12.9 and 11.0, respectively. Unlike conventional air–conditioners, the outdoor air temperature had a small influence on the COP of the tested GSHPs. The average temperature of water leaving the ground loop was 12 °C and the leaving water temperature varied by up to 3.7 °C throughout the cooling season. The total power consumption and operating cost of the tested GSHPs are less than conventional air–conditioners by up to 66%.