Performance investigation of a novel photovoltaic-thermal vapor injection heat pump based on 4E analysis

A novel photovoltaic-thermal vapor injection heat pump (PVHP) is proposed and analyzed in this paper, which owns remarkably superior performance by realizing cogeneration of electricity and thermal energy from solar energy. The operation characteristics of PVHP are evaluated based on built simulation model. It indicates that the solar assisted mode is suitable for extremely low or no solar radiation conditions, while the vapor injection mode is preferable to other conditions. There exists optimal combination of intermediate pressure and split ratio for PVHP to achieve the maximal comprehensive COP (coefficient of performance). The energy, exergy, economic and environmental performance of PVHP and traditional economized vapor injection heat pump (VIHP) are compared based on genetic algorithm. Thereinto, the heating COP and comprehensive COP of PVHP respectively exceed the heating COP of VIHP by averages of 18.4 % and 4.1 % under evaporating temperature range of −20 ∼ 5 °C. Moreover, PVHP can produce 4.2 % more heat exergy output with 12.2 % less net electricity consumption compared with VIHP. PVHP yields about 8.5 years payback periods in four northern China cities when adopted to replace VIHP in the considered application scenario, and significantly reduces the pollutant emissions. In addition, the optimal combination of comprehensive COP and levelized cost of energy is located at [5.55, 0.132 $ kWh⁻¹] by multi-objective optimization.