Air-, ground- and dual-source heat pumps: a comparison between energy-efficient systems for a Swedish dwelling

KTH Royal Institute of Technology - Department of Energy Technology, Stockholm, Sweden

^* corresponding author: mlfasci@kth.se

Abstract

Air-source heat pumps (ASHPs) and ground-source heat pumps (GSHPs) are the most spread heat pumps nowadays. However, they suffer from drawbacks that could be mostly overcome coupling the two heat sources, i.e., using dual-source heat pumps (DSHPs). In this study, we compared the techno-economic performance of ASHPs and GSHPs for a small Swedish single-family house. We also calculated the performance improvements achieved using dual-source heat pumps, and evaluated the economic conditions necessary to make the dual-source heat pumps economically competitive with the more traditional systems. We found that the GSHPs were more efficient than the ASHP during the first year of installation, but their performance decreased - sometimes dramatically - during their lifetime. However, investing in either systems was always beneficial and no significant differences tended to exist between the investments. The dual-source heat pumps had– sometimes significantly – higher performance than the conventional systems but they might not be economically competitive with the more conventional systems.