Flow boiling of R32 inside a brazed plate heat exchanger.

This paper presents recent measurements of heat transfer coefficient obtained during flow boiling of R32 inside a brazed plate heat exchanger (BPHE). Although R32 is known as a very interesting refrigerant for its thermodynamic and thermophysical properties, to the best of the authors’ knowledge, no flow boiling data are published in the open literature for this refrigerant working in brazed plate heat exchangers. The present experimental data are measured at the Department of Industrial Engineering at University of Padova. The experimental data are measured in order to investigate the effect of refrigerant heat flux, mass velocity, inlet vapor quality and superheating at the outlet. The saturation temperature is kept constant at around 5°C, which can be considered an interesting temperature level for evaporating temperature in liquid coolers. In the present paper data are also analyzed to assess available correlations for flow boiling inside BPHEs, in order to provide some guidelines on the predicting methods that should be used for evaporators using R32.