Analysis For The Micro-channel Heating Exchanger On Air Conditioning Equipment

During heating process, Micro-channel heating exchanger as evaporator on unit, How did the refrigerant be distributed, furthermore, refrigerant pressure drop gradient changes with different heat exchanger condition such as superheating area, phase change area and sub-cooling area, it is maximum in the phase change area, next with sub-cooling area and minimum in the superheating area.The unequal distribution of the refrigerant flux in the collection tube cause the unequal of the refrigerant in the Micro-channel evaporator flat tubes, then which cause the non-uniform surface temperature distribution. The start frosting point also is with the lowest surface temperature. As beginning, the frosting rate is high and then gradually reduce, the frost borderline gradually move from left to right, due to heating convection coefficient gradually reduce at air side which cause area heating exchanged reduce. But the frost borderline move from right to left in the frost thawing progress. The unequal distribution of the refrigerant flux in the Micro-channels of flat tubes led to uneven distribution of frost, furthermore, incomplete evaporation of refrigerant in some tubes may be a critical factor of folded-louvered-fins'easily frost under relative high environmental temperature condition...