Mathematical model construction and analysis of combined solar energy and air-source heat pump hot water unit system

 Based on the previous studies, proposes a mathematical model of a new air-source heat pump hot water unit system coupled with solar energy. In this model, revises an evaporator components to improve the reliability of the model, proposes the evaporator winter frost correction model (including the frost layer height and the frost layer effective thermal conductivity calculation models), and introduces the space radiation correction and dust reduction correction for the evaporator outdoor unit. The error between the calculated results of the system model and the measured results is less than 5%, which shows the better calculation accuracy. The solar energy coating can effectively absorb the solar radiation energy, improve the surface temperature of the evaporator and keep the stable operation of the coupling system, so that the coupling system has better heating performance.