Experimental and numerical investigation on a solar direct-expansion heat pump system employing PV/T & solar thermal collector as evaporator

The objective of the research is to present an investigation on the operational performance of the integrated photovoltaic/thermal system (PV/T) and solar thermal collector (TC) with a heat pump system (PVT-TC) and its potential use for generating high thermal energy and electricity simultaneously. The numerical simulation model and testing rig of the PVT-TC heat pump system have been developed to analyze the electrical, thermal, and total efficiency of the system. An experimental test was carried out under real weather conditions. The experimental results revealed that the average electrical, thermal efficiency, and coefficient of performance (COP) of the PVT-TC heat pump system are 14.08%, 66.71%, and 6.11, respectively. According to comparative analysis with the similar systems, the PVT-TC heat pump system exhibits a higher electrical and thermal efficiency, thus showing a better application potential in residential buildings. The PVT-TC system occupies 3.3278 m2 and generates an average of 0.86 kWh/day of electricity and 6.35 kWh/day of thermal energy, as a result of 86.1% of primary energy saving efficiency being obtained. In addition, the PVT-TC heat pump system is simulated using COMSOL Multiphysics® to examine the temperature distribution of the solar TC and PV/T systems. The numerical model is also verified by the experimental data, with a root mean square deviation with less than 1.53%. •A novel PVT-TC system coupled with a solar direct-expansion heat pump system.•An experimental study was conducted to analyze the performance of the novel system.•The average COP of the PVT-TC solar heat pump system was obtained to be 6.11•Average thermal efficiency of PVT-TC system was achieved to be 66.71%.