Condensate drainage on slit or louvered fins in microchannel heat exchangers for anti-frosting

When the condensate isn't removed in time, it is easy to cause frosting, which limits the application of microchannel heat exchangers (MCHE). Although some methods can measure well about improving the condensate drainage performance of the MCHE, the quantitative value of drainage amount can not be given in the operation condition of one actual refrigeration system. The objective of this study included developing a test facility to investigate condensate drainage in MCHE, and study condensing in MCHE to valuate different condensate detecting methods. In the present study, condensate drainage was experimentally investigated on louvered and slit fins in MCHE for anti-frosting. Experimental data of drainage amount, the moist air pressure drop across the test sample and the heat capacity of the MCHE were recorded. The calculation formula for drainage amount was set up. The rate of condensate drainage from the experimental system is mainly a function of the velocity with the dew point temperature and the dry bulb temperature of the moist air unchanged. The calculation value and the test value of the drainage amount were compared for four different structures MCHE with slit or louvered fins. The research result shows that for the given brine flow conditions, the rate of condensate drainage is mainly influenced by the air velocity, the calculation formula predictions of the condensate drainage agree well with the test measurement results, and the maximum deviation is 12%.This study provides reference for the application of micro channel evaporator.