Assessment of Ground Source, Air Source and Hybrid Heat Pumps for a Single Family Building in Cold Climates (ST-16-027)

This article attempts to address the issue of making the right choice between a Direct Expansion Ground-Source Heat Pump (DX-GSHP), an Air-Source Heat Pump (ASHP) and a hybrid of the two in a given heating need context. Detailed screening models previously developed for ASHPs and DX-GHSPs are first used to compare the seasonal performance of these two options for a residential building in the cold climate city of Montreal. Then, the performance of a so-called “Hybrid Ground Source Heat Pump (HGSHP)”, integrated air source and ground source system is also investigated. Furthermore, different parameters including borehole total length and heat pump capacity are varied in order to determine the appropriate design in terms of borehole size and heat pump capacity. The results show that by adequate sizing, energy consumption of the DX-GSHP system can be reduced by 50% but performance improvement using HGSHP system is marginal. Such results highlight the importance of further investigations in the area of DX-GSHPs, in order to reduce the borehole installation cost and increase its performance.