Investigation of solar assisted air source heat pump heating system integrating compound parabolic concentrator-capillary tube solar collectors

Solar assisted air source heat pump heating systems are capable of achieving green heating where solar availability essentially affects its operation performance and application potentials, especially in higher-latitude regions, such as UK. Compound parabolic concentrator solar collectors can achieve high collector efficiency at high hot water temperature, benefitting to improve solar collection and corresponding thermal energy storage capacities. Though compound parabolic concentrator solar collectors have been widely investigated, application of such collector for solar assisted air source heat pump system is not studied yet. The paper reports numerical simulations of solar assisted air source heat pump heating systems that integrate compound parabolic concentrator-capillary tube solar collectors for domestic heating in the UK. The results show that, for the same seasonal performance factor, the size of the concentrated solar collector required is 12 m2 whereas the size of the flat plate solar collector required is 18 m2. This suggests one third reduction in the size of solar collector, significant reduction in cost and convenience for installation. The results also show the potential to further reduce the size of the concentrated solar collector to 9 m2 or less. The high collector efficiency of the compound parabolic concentrator-capillary tube solar collector enables much small size of solar collector, significantly lower cost and convenient for installation and wide rollout of solar assisted air source heat pump heating system to locations where solar irradiance is relatively lower.