Greenhouse gas emissions analysis of heat pump water heaters coupled with air-based solar thermal collectors in Canada and the United States

摘要

Space and water heating contribute 62% and 21% of the residential greenhouse gas emissions (GHGs) in Canada, respectively, which corresponds to 11% of the GHGs within the country. Because both space and water heating are dominated by natural gas, the carbon footprint of Canada could be significantly reduced with a shift towards clean space and water heating, such as heat pump water heaters (HPWHs). HPWHs use electricity but are between two and three times more efficient than electric water heaters (EWHs). However, while they operate, HPWHs cool nearby ambient air which increases natural gas-dominant space heating loads. Solar assisted HPWHs (SAHPWHs) may allow the GHG reductions of HPWHs to be realized without increased space heating loads. The objective of this study was to assess the feasibility of HPWHs and SAHPWHs in terms of their GHG reductions across Canada and the United States. It was found that the systems reduced GHGs compared to EWHs and natural gas water heaters (NGWHs) in many locations, as indicated graphically within this paper. The locations and electricity grid mixes which have potential for the greatest GHG reductions are shown in this paper. (C) 2020 Elsevier B.V. All rights reserved.