Measurements of local heat transfer coefficient during condensation and evaporation in plate heat exchanger.

In the present study, condensation and evaporation local heat transfer coefficients of the R1234ze(E) inside a brazed plate heat exchanger were investigated by using a test section which is combined with two grooved stainless steel plates. The test section consists of eight plates; two of them were processed herringbone for refrigerant flow channel other two flat plates are set for heating/cooling plate for refrigerant, and another consist on heating/cooling water flow channel. In order to measure local heat transfer and temperature distribution, 40 thermocouples were set at not only flow direction but also in the right and left sides of plates. Local heat transfer coefficient distribution was calculated from the wall temperature and local heat flux. Refrigerant flows downward in the condensation test and upward in the evaporation test, respectively.