Improving cold climate performance of heat pumps using market-available systems

Abstract

Air source heat pumps are an excellent electric alternative to fossil fuel based heating systems for reducing residential greenhouse gas (GHG) emissions, but common mild climate systems suffer significant performance losses at the low outdoor temperatures experienced in cold climates. Improved heat pumps for cold climates already exist, but they are more expensive and their adoption has been relatively low. An analysis was conducted to assess the status of market-available cold climate heat pump technologies and identify opportunities in the literature that might further improve performance and uptake. A new cascade heat pump system was then proposed for rapid implementation in cold climates, since it is composed of two simple and well-established heat pumps models, compatible for replacing/retrofitting common centrally-ducted natural gas furnaces. Performance modelling and comparative analysis concluded it could out-perform all comparable market-available cold climate systems at −15 ◦C, with the potential to operate efficiently at even lower temperatures.