Study On Performance Evaluation Of Low Ambient Temperature Air Source Heat Pump(Water Chilling) Packages Heating System

It is known that air source heat pump heating system is a heating way with high refrigerating efficiency and energy saving. However, in low temperature environment, heating capacity of the air source heat pump systems declines and heat transfer would be weaken since the surface of evaporator surface of the system will be frosted. Therefore, the adaptability and performance evaluation of the air source heat pump heating system working at low ambient temperature receive more attention.Based on the study on the low ambient temperature air source heat pump technology at home and abroad, this paper introduced the working principle of air source heat pump, analysised the impact of low ambient temperature on air source heat pump, and summarized measures to improve the performance of air source heat pump system in low temperature environment. The improvement of thermal cycle expanded the scope of application of air source heat pump in low temperature environment.Combined with the climate characteristics and the heating condition in China, in accordance with the provisions of the energy efficiency of low ambient temperature air source heat pump packages standard as well as current energy efficiency level, the paper delineated application scope of low ambient temperature air source heat pump according to the mean indicators of outdoor environment temperature and relative humidity, which provides reliable basis for engineering application.The main composition of low ambient temperature air source heat pump heating system is described. Through the analysis of the evaluation index of low ambient temperature air source heat pump heating system, the framework of performance evaluation system is established. This paper described the definition, the calculation formula and for parameters acquisition method of the evaluation index, which can evaluate the low ambient temperature air source heat pump heating system qualitatively and quantitatively. The establishment of performance evaluation system will solve the problems of low energy efficiency, poor economy and serious environmental pollution effectively.Finally, through the analysis and calculation of energy efficiency, economy, environmental evaluation index of the air source heat pump heating system of a hotel building in Lhasa area, which verified the performance evaluation of low ambient temperature air source heat pump heating system is scientific, rationabie and operational. At the same time, some policy proposals were put forward which provides a theoretical basis for the popularization and application of the low ambient temperature air source heat pump heating system.