Thermodynamic performance of an air source heat pump integrated with an air-based solar collector for radiant floor-based space heating in cold climates.

Heat pumps have gained recognition as an effective technology for domestic hot water production and space heating, owing to their high efficiencies and potential to significantly reduce carbon emissions and reliance on fossil fuels. Nevertheless, the performance of air source heat pumps (ASHPs) is highly sensitive to ambient temperature, with their efficiencies declining sharply at extremely low temperatures. This study examines the enhancement of the thermodynamic performance of an ASHP integrated with a solar air collector (SAC) for residential space heating in extremely cold climates, with Calgary, Canada, as a case study. A heating model of an ASHP coupled with the SAC and a thermal energy storage (TES) tank was developed and implemented in a transient system simulation tool (TRNSYS). The system is further connected to a building energy model via a radiant floor-heating system for space heating. The performance of the integrated heating system is evaluated based on key parameters, including the coefficient of performance (COP), energy consumption, and heat pump fraction (HPF). This research investigates the impact of varying collector sizes and different lower evaporator temperature limits on ASHP performance. Additionally, the study uses actual building energy loads from an energy model of a small, single-storey house designed for three occupants. The findings reveal that integrating a 40 m 2 SAC enhances the ASHP's COP by approximately 7%. Further, the system demonstrates the capability to maintain indoor temperatures within the desired range for over 97% of the year. The study highlights the potential of integrating solar energy with ASHPs to decarbonize residential space heating systems. • A detailed heat pump – solar air collector-thermal energy storage model is developed • The potential of the system for space heating in extremely cold climates is investigated • Air recirculation within the solar air collector enhances the COP by up to 24%. • The heat pump COP improves from 2- 4 to 2-6 with the integration of SAC and TES.