Thermo-Hydrodynamic of the Evaporation of Refrigerant R134A in Brazed Plate Heat Exchangers

The evaporation of refrigerant R134a in three different sizes of Brazed Plate Heat Exchangers (BPHE) is analyzed in this article. The BPHEs are a type of compact plate heat exchanger with parallel corrugated plates which are brazed together in series. In this study, these heat exchangers are utilized as the evaporator of an automotive refrigeration system, and their heat transfer coefficients and pressure drops are obtained experimentally. The refrigerant flows on one side and a 50% glycol-water mixture on the other side of the BPHEs, in a counter flow configuration. The heat transfer coefficient for the single-phase glycol-water mixture flow through the BPHEs is obtained using the Wilson plot technique. The single-phase Fanning friction factor correlation is also obtained using experimental results from the hydrodynamic parameters of glycol-water mixture. The results from the single-phase flow analysis are then extended to the two-phase flow analysis to correlate the evaporation heat transfer and pressure drop for the refrigerant R134a in the BPHEs. In summary, the thermo-hydrodynamic behavior of the evaporation of R143a in brazed plate heat exchangers is analyzed and compared with previous studies.