Comparative thermal performances of a ground source heat pump and a variable capacity air source heat pump systems for sustainable houses

• Comparative performance investigation of ground and air source heat pumps.
• Experimental study, data extrapolation and TRNSYS simulation were performed.
• Annual performances of GSHP and ASHP systems predicated for major Canadian cities.
• COP of ASHP ranged from 4.7 to 5.7 and GSHP ranged from 4.9 to 5.6 for cooling.
• COP of ASHP ranged from 1.8 to 5.0 and GSHP ranged from 3.05 to 3.44 for heating.

This paper presents a performance comparison of a variable capacity Air Source Heat Pump (ASHP) and a horizontal ground loop Ground Source Heat Pump (GSHP). Both these systems were installed side-by-side at the Archetype Sustainable Twin Houses at Kortright Center, Woodbridge, Ontario, Canada. The heat pumps were tested in both heating and cooling modes for extreme weather conditions of Ontario. For cooling mode, the coefficient of performance (COP) of ASHP ranged from 4.7 to 5.7 at an outdoor temperature of 33 °C and 16 °C respectively, while the COP of GSHP ranged from 4.9 (at an ELT of 8.5 °C and EST of 19.2 °C) to 5.6 (at an ELT of 12.4 °C and EST of 17.8 °C). For heating mode, the COP of ASHP ranged from 1.79 to 5.0 at an outdoor temperature of −19 °C and 9 °C respectively, while the COP of GSHP ranged from 3.05 (at an ELT of 44.4 °C and an EST of 2.7 °C) to 3.44 (at an ELT of 41.5 °C and an EST of 5.48 °C). Data extrapolation and TRNSYS simulation were also performed to predict annual performances of each system for major Canadian cities.