Research Of Applying Microchannel Heat Exchanger To Refrigeration Compressor Condensing Unit

As a high-efficiency heat exchanger, microchannel heat exchanger has been widely used in automobile air-conditioning and is promoted using in residential air-conditioning. Research of applying microchannel heat exchanger to refrigeration compressor condensing unit is carried out in this paper. The research includes design of microchannel heat exchanger in refrigeration compressor condensing unit, microchannel heat exchanger simulation and optimization, and experimentation.Computation formulas of microchannel heat exchanger heat transfer area are presented. So are the heat transfer coefficient correlations which are suitable for microchannels. Design method of microchannel heat exchanger is discussed according to the development of a new compressor condensing unit model. The engineering estimation of total heat transfer coefficient is given.Microchannel heat exchanger simulation and optimization are organized using distributed-parameter method. Variation trends along the length direction of refrigerant-side heat transfer coefficient, refrigerant pressure drop, and total heat transfer coefficient are analyzed according to the simulation result. The optimization of pass arrangement, tube and fin width, tube height, fin pitch, fin height, number of webs, louver pitch, and louver angle are carried out with the purpose of the lightest weight and the biggest heat duty.The experimentation study of microchannel heat exchanger is divided into two parts. Part One measures the heat duty of microchannel heat exchanger using room heat balance method, by which we can judge the practicability of the simulation model. Part Two compares the traditional tube-fin heat exchanger and the microchannel heat exchanger used in compressor condensing unit. The result indicates that the difference of simulation value and experimentation value is small; the performance of refrigeration system is improved obviously after replacing tube-fin heat exchanger with microchannel heat exchanger.