04. Boiling and Multi-Phase Flow

Due to global warming, the European Union has banned the future use of refrigerants with GWP (Global Warming Potential) higher than 150. Therefore, HCFC and HFC refrigerants will be phased out in air conditioning systems. The new refrigerant R-1234yf is an alternative to R-134a due to its lower GWP and similar thermodynamic properties. This study provides an experimental analysis of the condensation heat transfer performance and pressure drop of R-134a and R-1234yf in a plate heat exchanger. Under lower mass flux conditions, heat transfer is affected by the thickness of the condensation film, It was observed that R-1234yf and R-134a have a similar heat transfer coefficient, due to the effects of thermal conductivity and liquid viscosity. However, under higher mass flux conditions, it was observed that the heat transfer coefficient of R-134a is around 15% higher than that of R-1234yf s due to the increasing influence of inertial force, making thermal conductivity the primary factor controlling heat transfer performance. This study suggests that R-1234yf is a suitable replacement for R-134a for air conditioning systems.