Plate heat exchanger, evaporation, condensation, R1234yf
In this study, boiling and condensation heat transfer characteristics of refrigerant R1234yf flowing inside a channel of plate heat exchanger were experimentally investigated. The test section consists of 8 plates where the refrigerant flow channel is formed by two plates grooved chevron pattern. Other plates are used to measure local temperature distribution and to form cooling /heating water channel. In this experiment three vertical flow channel exist in the test section and where the refrigerant flows in the middle channel (upward or downward directions) depending on evaporation or condensation process. In case of evaporation process the refrigerant flows upward in the middle channel and heat source water flows downward in the outer two channels. In condensation, refrigerant flows downward in the middle channel and the cooling water flows upwards in the two outer channels. In the test section, there are 160 measurement points in total with 4 sets of 8 symmetrical points in the horizontal direction and 5 symmetrical points in the vertical direction. In order to measure local heat transfer characteristics of the R1234yf, 20 thermocouples were set in the test section for measurement of wall temperature of the refrigerant and heat source water side. Local heat transfer coefficient was obtained under the experimental conditions of the mass flux of 10kg/(��2s) and 50 kg/(��2��). The local heat transfer coefficient is varied in horizontally and vertically. Local dryout in evaporation process was identified. The data of the R1234yf was also compared with the R32.