Performance of solar-air source heat pump heating system aided by district heat supply network research

Abstract

Abstract To improve the usage rate of district heat supply network and solve the frost problem in solar-air heat pumps, this study used TRNSYS to construct a new solar-air source heat pump heating composite system that uses waste heat from the district heat supply network. The impact of the waste heat recovery device on the heating performance of the new composite system was analysed, and the economic and environmental performance of the composite system was compared with other heating systems. During a typical day, the average coefficient of performance of air source heat pumps (COP) of the composite system increased by 13% and the power consumption of the system decreased by 35.9%. Throughout the heating season, the power consumption of the composite system was 13.59% higher than that of traditional systems, and system coefficient of performance (SCOP) was 15.89% lower than traditional systems. Based on economic analysis, the relative operating costs of the composite system, coal-fired boiler, gas-fired boiler, oil-fired boiler and combined heat and power (CHP) are 1, 1.19, 2.33, 5.56 and 0.85, respectively. The operating cost of the composite heat source system is only 17.43% higher than that of CHP and lower than the other three heating systems. Quantitative evaluations of the environmental friendliness of these systems were conducted using the fuzzy analysis mathematical method. The evaluation results were 9.62, 5.89, 15.05, 9.10 and 6.79, respectively. It was found that the composite system is second only to the gas-fired boiler in terms of environmental friendliness and is 38.9% higher than the coal-fired boiler and 29.5% higher than the CHP.