Energy and exergy analysis of a solar-assisted heat pump space heating system for clear days

The studies over solar-assisted heat pump systems have been performed mostly on time periods when solar radiation is high. Therefore, this study focuses on performance analysis of a solar-assisted heat pump system which stores the energy during the clear day and uses it as a heat source of heat pump space heating system during the night. Energy and exergy analyses divided into two parts, which are the analyses of solar water heating system (SWHS) and water source heat pump space heating system (WSHPSHS). As a result, the exergy efficiencies of the heat pump unit and WSHPSHS were 84.9% and 79.5%, respectively while the corresponding COP values were 2.95 and 2.68. Also, the exergy efficiency of the SWHS was obtained to be 7.28%. The greatest irreversibility occurs in evaporator, fan-coil unit and solar collector for the heat pump unit, WSHPSHS and SWHS, respectively.