Condensation and evaporation local heat transfer characteristics of the refrigerant mixture of R1123 and R32 inside a plate heat exchanger

In the present study, condensation and evaporation local heat transfer coefficients of the refrigerant mixture of R1123 and R32 inside a brazed plate heat exchanger were investigated by using a test section which is combined with two grooved stainless steel plates. In the test section, wall temperature distribution was measured. The test section consists of eight plates; two of them were processed herringbone for refrigerant flow channel other two flat plates are set for cooling plate for refrigerant, and another consist on cooling water flow channel. In order to measure local heat transfer and temperature distribution, five thermocouples were set on flow direction for each wall temperature measurement of the refrigerant side and heat source water side. Local heat transfer coefficient were calculated from local wall temperature of refrigerant side, saturation temperature and local heat flux obtained by temperature gradient between heat transfer surface of refrigerant side and heat source side

Evaluation on Heat Pump Cycle Considering Heat Transfer Degradation of Mixture Refrigerant

A low GWP refrigerant R1234ze(E) is focused as a candidate of next-generation refrigerant though it has some defects which are low operating pressure and low latent heat. Mixing R32 into R1234ze(E) expects to reduce the defects because R32 has high operating pressure, large latent heat and high thermal conductivity. In order to prove the possibility, heat transfer coefficients during condensation and evaporation were obtained experimentally and cycle simulations were carried out where heat transfer degradation of refrigerant mixture was estimated with the experimental data. An equivalent performance with conventional refrigerant was obtained by the simulation