二次冷凝除霜冷库制冷系统运行特性  

Performance of secondary condensation defrosting cold storage refrigeration system

作　　者：刘琼瑜 肖波 刘军 吴耀森 涂桢楷 刘清化 龚丽 LIU Qiongyu;XIAO Bo;LIU Jun;WU Yaosen;TU Zhenkai;LIU Qinghua;GONG Li(Guangdong Hongke Agricultural Machinery Research Institute Co.,Ltd,Guangzhou 510555,China;Guangdong Institute of Modern Agricultural Equipment,Guangzhou 510630,China;Key Laboratory of Modern Agricultural Intelligent Equipment in South China,Ministry of Agriculture and Rural Affairs,P.R.China,Guangzhou 510630,China)

机构地区：[1]广东弘科农业机械研究开发有限公司,广州510555 [2]广东省现代农业装备研究所,广州510630 [3]农业农村部华南现代农业智能装备重点实验室,广州510630

出　　处：《农业工程学报》2023年第15期268-275,共8页Transactions of the Chinese Society of Agricultural Engineering

基　　金：2022年乡村振兴战略专项省级组织实施项目资金(第1批)(粤财农〔2022〕92号);广东省科技创新战略资金项目(粤科资字[2021]133号)。

摘　　要：针对冷库蒸发器除霜能耗大的问题,以二次冷凝除霜冷库为研究对象,建立了系统热力学模型,通过试验验证了二次冷凝除霜模型的有效性,并对比热气旁通除霜模型验证其节能性。为优化二次冷凝除霜冷库除霜性能,设计试验研究不同因素对系统运行能耗的影响,通过改变不同的蒸发器传热温差、蒸发温度和冷凝温度,获得系统除霜周期能耗并进行对比分析。结果表明:1)蒸发器传热温差宜取7~9℃;2)蒸发温度降低,二次冷凝除霜周期能耗增加,但相比热气旁通除霜节能性增加,当冷凝温度为34~38℃,蒸发温度为−20~−10℃时,单位冷库容积二次冷凝除霜周期能耗为0.055~0.080 kW·h/m^(3),相比热气旁通除霜节能12.7%~15.8%;3)冷凝温度增加,二次冷凝除霜周期能耗增加,同时相比热气旁通除霜节能性增加,当蒸发温度为−15℃,冷凝温度为34~38℃时,单位冷库容积二次冷凝除霜周期平均能耗为0.0675~0.0785 kW·h/m^(3),相比热气旁通除霜节能12.3%~16.5%。该研究可为制冷系统的节能运行提供参考。An optimal performance can greatly contribute to the energy saving of refrigeration systems in cold-chain logistics.Since lots of agricultural products need to be kept at a temperature below 0℃,cold storage can be expected to store food products over a long time without spoiling.However,a great challenge is the defrosting energy consumption of lowtemperature cold storage.Two problems can occur during defrosting.One is that the ever-increasing temperature can cause food preservation in cold storage.Another,it takes lots of energy in the defrosting period.In this study,a new defrosting approach was proposed for cold storage refrigeration,which was called secondary condensation defrosting.The specific defrosting cycle was summarized as follows:Firstly,a certain proportion refrigerant was obtained to reduce the pressure from the condenser outlet.Secondly,the defrosting refrigerant flew into the first evaporator,where the maining refrigerant was transferred the heat into it.Thirdly,the defrosting refrigerant came into the frosty evaporator and then released the heat to melt the frost layer,finally the refrigerant was condensed again(called secondary condensation defrosting).The secondary condensation defrosting decreased the temperature in the cold storage for energy-saving in the defrosting refrigerant,compared with the hot-gas defrosting.The thermodynamic model was established for the secondary condensation defrosting.The effectiveness and energy saving of the model were also verified by the experiments.A comparative analysis was performed on three indexes:evaporator heat transfer temperature difference,evaporation temperature,and condensation temperature.The results show that:1)The better performance was achieved in the secondary condensation defrosting of cold storage when the evaporator heat transfer temperature difference between 7-9℃.2)The energy consumption of the secondary condensation defrosting cycle increased significantly with the decrease in evaporation temperature.But more energy saving was obtained

关 键 词：制冷系统 二次冷凝除霜 热气除霜 除霜能耗 

分 类 号：TB657[一般工业技术—制冷工程]