Assessment of Optimal Operating Range and Case Verification of a Waste Heat Air-Source Heat Pump Water Heater Based on a Semiempirical Parametric Model

Abstract

Waste heat air-source heat pump water heater (WH-ASHPWH) systems have been widely used to provide water heating in buildings due to their advantages of high efficiency and low environmental impact. It is important to determine reasonable operating conditions for WH-ASHPWH systems to improve their heating efficiency, especially for systems using industrial waste heat. In this study, a semiempirical parametric model of a WH-ASHPWH system was established to simulate heating performance under different working conditions and determine the optimum operating range of the system. A new discrete model for a tube-in-tube condenser was also generated. Taking the equipment of a pharmaceutical factory as an example, the heat exchanger model was first calibrated; then, the global model was used to study the effects of different air-side and condenser-side waste heat conditions on the heating performance of the system. According to the simulation results, the coefficient of performance (COP) reached a maximum value of 4.5 under the optimum working conditions. The deviation between the COP simulation data and experimental values was less than 8.28%, and the simulation time was less than 8 min. These metrics indicate that the model is reasonable and efficient.