Performance of micro-fin tubes with refrigerant-22 and oil mixtures

Compressor lubricating oil is mixed with the refrigerant circulating in a vapor compression refrigeration system. Information on the heat transfer and pressure drop effects of oil is needed to design better heat transfer components. Furthermore, energy and heat exchanger size considerations are leading to an increasing use of tubes having enhanced heat transfer surfaces. Thus, data on the performance of these tubes are becoming more important. To address these two related issues, ASHRAE Technical Committee 1.3 sponsored research project 469-RP. This article highlights the results of 469-RP. The research project was divided into three phases; review of the literature, experimental investigation, and development of correlation expressions. The results of the experimental investigation are emphasized in this article.