engleski

Comparison of the thermal performance of the solar assisted heat pump to the conventional solar system

Solar assisted heat pump (SAHP) systems are nowadays rarely presented on the growing solar market compared to the conventional solar hot water systems. Due to higher collector efficiency in the SAHP systems ( coll = 0.6  0.9) than in conventional solar systems ( coll = 0.3  0.6), and due to the fact that the SAHP systems can operate in periods with the solar irradiation of reduced or even negligible intensity, e.g. in cloudy weather or during the night, SAHP attract the increased attention of researchers and designers. Experimental and analytical studies were carried out on a SAHP consisting of two flat-plate solar collectors acting as an evaporator for the refrigerant R134a, a variable-frequency reciprocating type compressor, a compact plate heat exchanger (condenser) and an electronic expansion valve. Experimental results enabled the creation of a solar-assisted heat pump simulation model. The simulation model developed for the water heating energy gained for year round analysis enables the design of SAHP as well as the assessment of the efficiency of the SAHP compared to conventional solar systems. Simulation results have shown that the heating capacity of SAHP is by 100 % higher than the heating capacity of conventional solar water system (CSWS) for the same collector area and meteorological conditions. The results of the system thermal performance simulation are obtained for the meteorological conditions of Croatian Adriatic area.

Thermal performance; solar heat pump; conventional solar system

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