Performance of new microchannel evaporators and condensers for air conditioning equipment.

Aluminum heat exchangers are an interesting solution for refrigeration and air conditioning application since they maintain high performance while reducing weight and manufacturing costs. In the present paper, a two-phase heat transfer characterization of a new aluminum microchannel heat exchanger is presented. The heat exchanger is composed by rectangular channels with internal perforated turbulators. A unique test section has been designed and realized in the Two Phase Heat Transfer Lab of the University of Padova in order to measure the refrigerant heat transfer coefficient during flow boiling and condensation. The test section has a single refrigerant channel with perforated fins to produced the microchannels. The refrigerant tested is R32. The aim of the present paper is to investigate the performance of these innovative microchannel heat exchangers as condensers and evaporators in air-conditioning equipment, since very few data are available in the literature regarding flow boiling and condensation in similar geometries.