Condensation heat transfer of R1234ze(Z) in the vertical channels

Recently, the development of high temperature heat pump systems for heat recovery from industrial waste heat below 100 °C is one of important subjects in order to reduce primary energy consumption. However, in order to develop such systems, it is indispensable to use an environmentally acceptable refrigerant, highly efficient heat exchangers and highly efficient compressors. From this viewpoint, in the present study, the condensation of low GWP refrigerant R1234ze(Z) in vertical channels is investigated experimentally in order to establish optimum design method of plate-fin heat exchanger. Two type of fins are used in the experiment, one is plane fin, another one is serrated fin. In the test channel, the test refrigerant flows downward, while the compressed cooling water flows upward. The local heat transfer characteristics are measured using thermocouples, heat flux sensors and pressure transducers. Also, the experimental results are compared with correlation equation that are composed free convection condensation. As the results, it clarified that heat transfer characteristic in plate fin heat exchanger are different according to difference in fin shapes. The heat transfer characteristics in plate-fin heat exchanger, at low quality area, are phenomenon that is near to free convection condensation.