Performance optimization of solar-air composite source multi-functional heat pump with different control schemes

Abstract Heat pump is a promising approach for low carbon heating/cooling driven by renewable electricity and adapting to multiple heat sources. In this paper, solar-air composite source multi-functional heat pump (SA-CMHP) with the capabilities of space heating, domestic water, space cooling, heat storage, and defrosting has been proposed to provide effective heating/cooling supply solutions for buildings. In SA-CMHP, as the distribution of refrigerant at evaporation side has great impact on its space heating and water heating performance. To optimize its performance under different working conditions, two different control schemes are developed. Mathematic model is established to evaluate and compare the behavior of SA-CMHP under different control schemes. The results reveal that control scheme 1 should be employed when the solar irradiation is insufficient, otherwise, control scheme 2 is more effective for space heating mode. Meanwhile, control scheme 1 should be adopted in water heating mode under different working conditions, as control scheme 1 can effectively reduce the heat loss to environment at evaporation side during the water heating process due to the capability of adaptive regulation of mass flow rate distribution at evaporation side.