冷库系统变工况性能的理论分析

Thermodynamics Analysis of Ammonia Vapor Compression Refrigeration Systems in Cold Store on Variable Conditions

对氨冷库蒸汽压缩制冷系统进行理论分析。通过改变环境温度,改变蒸发器和冷凝器压力降,建模计算了冷库系统的损失、效率和制冷系数COP,结果表明,系统各设备的损失随着环境温度升高而变化,系统设备性能随着压力降升高而变化。认为减少蒸发器和冷凝器的传热温差,减少压缩机内不可逆损失,减少蒸发器的压力降等可以提高系统性能。

This paper presents a thermodynamics analysis of an actual vapour compression refrigeration cycle in the cold store uses ammonia as refrigerant, by changing the dead state temperature and by changing the pressure drop of evaporator and condenser separately, to simulate and calculate the exergy destruction, the exergy efficiency and the coefficient of performance （COP） of the system. The results indicate that the exergy destruction of the component of the system changes with the increase of dead state temperature; the performance of the system changes with the increase of the pressure drop in evaporator and condenser. The performance of the System could be improved by decreasing the value of such parameters, the heat transfer difference of both or either of the evaporator and the condenser, and by reducing irreversible loss of the compressor and the pressure drop of the evaporator.