不同库温下液体冷媒除霜系统的实验研究

Experimental study on the liquid refrigerant defrost system in the different temperatures

液体冷媒除霜系统具有在除霜期间制冷过程连续、库温波动小、无需附加能耗的优势。为探究液体冷媒除霜系统在不同温度下的性能,探究系统的应用范围,在库温分别为-5、-15和-20℃三种不同工况下,对库温、冷风机进出口温度和过冷度等参数进行了测量与分析。结果表明:在不同工况下,随着库温的降低,系统的过冷度不断增大,最高可达30℃以上;在除霜过程中,虽然蒸发面积减半,但制冷系统仍能输出较大的制冷量,维持库温恒定。因此,液体冷媒除霜系统可用于空调工况下的恒温恒湿系统、小型冷库系统和要求制冷过程不能停止的速冻装置。

The liquid refrigerant defrost system has many advantages： the refrigeration process is continuous during the de- frost period ; the temperature fluctuation of the cold storage is small ; and there is no additional energy consumption. In order to investigate the performance of the liquid refrigerant defrost system under the different temperatures and the application scope of the system, the experiments were carried out. And the working conditions were - 5, - 15 and - 20℃ respectively. The cold storage temperature, the inlet and outlet temperature of the evaporator and the undercooling were measured and analyzed. The re- suits show that the undercooling increases with the temperature reducing in the different conditions. The undercooling can reach more than 30℃. And the evaporation area reduce by half, but the refrigeration system can still output a large refrigeration capaci- ty to maintain the temperature constant in the defrost process. Therefore, the liquid refrigerant defrost system can be used in the constant temperature and humidity system, the small cold storage system and the quick freezing device which can not be stopped during the refrigeration.