Cooling and condensation heat transfer and pressure drop of a refrigerant at high pressures in a chevron-type plate heat exchanger with high chevron angle

In industrial fields, heat source over 130°C are widely needed, and for this development of industrial high-temperature heat pump systems has been promoted. For the heat release process in such the heat pump systems, it is considered to use of a plate heat exchanger (PHE) in which a high pressure working refrigerant flows. In this study, to examine the effect of chevron angle on heat transfer of refrigerants flowing in chevron PHEs at supercritical pressure and high subcritical pressure, experiments were conducted using a chevron PHE with a chevron angle 75°. The measured heat transfer coefficient was compared with the data of three chevron PHEs with respective chevron angles 30°, 47.5° and 65° obtained previously. The effect of chevron angle on heat transfer at 65° and more was smaller than that at less than 65°, and the heat transfer coefficient in 75° PHE was almost the same with that in 65° PHE, considering difference in hydraulic diameter between the PHEs. Furthermore, the value of heat transfer coefficient achieved in 65° or 75° PHE was estimated to be almost maximum between 0° to 90°. On the other hand, the friction factor of 75° PHE was markedly larger than that of 65° PHE.