Heat transfer characteristics of falling film and pool boiling evaporation in hybrid evaporator in vapor compression system

This paper proposes the hybrid evaporator using both falling film and pool boiling evaporation processes. Area ratio, defined as the ratio of the falling film to the total heat transfer area, was introduced, and experimental works characterized the evaporation heat transfer mainly in terms of film Reynolds number of feed refrigerant for several area ratios. Three types of tube configurations were also tested to find the enhanced heat transfer. Experimentally evaluated heat transfer assessed both the overall heat transfer coefficient and the convective heat transfer coefficient for each tube configuration for several area ratios. The enhanced heat transfer was observed by the use of the surface-modified tube and a lower area ratio also promoted the heat transfer.