商超冷柜冷凝热回收的热气旁通除霜性能研究

Study on hot gas bypass defrosting performance of condensing heat recovery in supermarket freezing cabinet

商超冷柜因箱体内无霜、可利用空间大、清洁卫生等优点得到了快速的发展,但同时也因其蒸发器表面除霜耗电量大的缺点受到局限。除霜尤其是冬季除霜对商超冷柜来说是十分重要的话题。热气旁通除霜方式的运用减小了传统电热除霜的功耗,但是也存在低温环境下压缩机吸气温度低、除霜时间长等问题。为解决上述除霜问题,对商超风冷无霜立式冷冻柜原有的热气旁通除霜管路进行改造,提出一种新型蓄热化霜系统。通过在系统中添加相变蓄热换热器来蓄存系统运行时的冷凝热,并在系统热气旁通除霜过程中释放热量,以提升压缩机的吸气温度。通过将改装后系统与原系统在不同环境温度下进行除霜性能测试,得出如下结论:在冬季气温下,改装后系统的除霜时间缩短为原系统的5%,除霜功耗减小为原来的5.6%,可以解决原系统冬季除霜效率低的问题。

Supermarket freezing cabinet have been rapidly developed due to the advantages of frost-free inside the box,large available space,and clean sanitation.However,the development is limited by the large power consumption of defrosting on the evaporator surface.Defrosting,especially in winter,is a very important topic for supermarket freezing cabinet.The application of hot gas bypass defrosting method reduces the power consumption of traditional electric heater defrosting,but there are also problems such as low suction temperature of compressor and long defrosting time in low temperature environment.In order to solve the above defrosting problems,the original hot gas bypass defrosting pipeline of air-cooled frost-free vertical freezing display cabinet in supermarket is reformed,and a new heat storage defrosting system is proposed.The heat exchanger with phase change heat storage is added to store the condensing heat during the operation of the system,and the heat is released in the process of hot gas bypass defrost to improve the suction temperature of the compressor.By testing the defrost performance of the modified system and the original system in different ambient temperatures,the following conclusions are drawn:in winter temperature,the defrost time of the modified system is shortened to 5%of the original system,and the defrost power consumption is reduced to 5.6%of the original system,which can solve the problem of low defrost efficiency of the original system in winter.