风冷太阳能双级氨喷射制冷系统冷藏工况性能分析

Performance Analysis on a Solar-powered Air-cooled Two-stage Ejector Refrigeration System with Ammonia as Refrigerant at Cold Storage

通过建立数学模型,对额定制冷量为9.4kW的冷藏库用风冷太阳能双级氨喷射制冷系统进行了变工况性能分析。该系统的制冷量随冷藏温度升高而增大,随环境温度升高而减小,随太阳辐照度增强而增大;COP的变化规律与制冷量类似,其差别是随太阳辐照度增强先迅速增大,但当太阳辐照度增大到一定程度后,COP的变化趋于平缓。在正常使用条件下(冷藏温度不低于4℃,环境温度不高于38℃,太阳辐照度不低于500W/m2),系统的制冷量为6.3～26kW,COP为0.042～0.087。该系统能较好地与亚热带典型城市南宁的果蔬盛产季节气候条件相匹配。

By the establishment of a mathematical model on a solar-powered air-cooled two-stage ejector refrigeration system using ammonia as refrigerant,the performance of ejector refrigeration system with rated refrigeration capacity of 9.4kW for cold store was analyzed.The refrigeration capacity of the proposed system increases with the rising of cold storage temperature and the enhancement of solar irradiance,while decreases with the rising of ambient temperature.The COP has similar changing trend with that of the refrigeration capacity except that it increases rapidly with the enhancement of solar irradiance firstly and then become stable after solar irradiance exceeding a certain value.The refrigeration capacity is 6.3-26kW and the COP 0.042-0.087 under the normal operating conditions with cold storage temperature over 4℃,ambient temperature below 38℃ and solar irradiance surpassing 500W/m2.The proposed system can match the climatic conditions in fruits and vegetables harvest season of Nanning,a typical city in subtropical zone.