Thermo-environ-economic analysis of a novel solar-assisted heat pump system; comparison with conventional single stage and cascaded air source heat pumps

The energy-intensive building sector is responsible for energy-raised negative environmental impacts and GHG emissions worldwide, motivating expectations to apply net-zero emission systems in many countries. Considering the huge energy consumption in building section, using novel and clean technologies is a necessity, where PVT integrated heat pump (HP) systems can properly fulfil the building's diverse energy demands. As the heat pump systems consumes electrical energy, integration of PVT panels with HP units can decrease or eliminate the need for local electricity grid and will moderate the negative effect of cold climate conditions on thermal performance of the conventional air-source heat pumps. This study proposes a novel configuration of integrated PVT-HP with cascade cycle and investigates its thermal, exergy, economic and environmental performance. A detailed comparison is also made between developed PVT-HP performance with that of single-stage and cascaded air-source heat pumps. The monthly performance of the three systems are examined for a real case study location using real-world climatic conditions. The results indicated superior performance of developed integrated PVT-HP system compared to two conventional ASHP units in terms of energy, exergy, and environmental indices, while, it yields higher levelized cost of heating due to higher capital expenditures. The developed integrated PVT-HP with cascade cycle in this work has higher COP by 11.8 % and 3.3 % compared to cascade cycle-ASHP in July and January, respectively. If there is no limitations on financial resources, the proposed PVT-HP system would be an excellent alternative with significantly higher COP and lower emission.