Performance Evaluation of an Innovative Photovoltaic–Thermal Flash-Tank Vapor Injection Heat Pump for Simultaneous Heating and Power Generation

Amid escalating global energy demand and heightened environmental concern, this study presents an innovative photovoltaic–thermal flash-tank vapor injection heat pump (PFVHP). This system integrates a photovoltaic–thermal (PVT) module into a conventional flash-tank vapor injection heat pump (FVHP) to realize simultaneous heating and power generation. Two distinct operation modes are designed for the PFVHP: TS-mode (two-source mode) for most solar radiation conditions and AS-mode (air-source mode) for low- or no-solar-radiation conditions. The energy, exergy, economic, and operational emission performance of the PFVHP are theoretically analyzed and compared with those of the FVHP. The findings reveal that the PFVHP can achieve a maximum cycle and system coefficient of performance (COP) at the respective optimal intermediate pressures. Exergy analysis indicates that enhancing solar radiation helps the PFVHP produce more heat exergy and electricity, but reduces the system exergy efficiency. As the evaporating temperature ranges from −20 °C to 5 °C, the cycle COP and system COP of the PFVHP are, respectively, 8.5% to 6.3% and 50.0% to 35.2% higher than the COP of the FVHP. The exergy flow comparison demonstrates that the PFVHP significantly enhances the system performance by reducing the overall exergy loss in devices excluding a PVT module, benefiting from the absorption of solar exergy by the PVT module. Economic and operational emission analyses indicate that the PFVHP offers a payback period of 9.38 years and substantially reduces the air pollution emissions compared to the FVHP.