Experimental flow boiling heat transfer performance of R290/R600a 50%/50% and R134a/R290/R600a 40%/30%/30% in a horizontal helical evaporation coil. 

In the last two decades, researchers have used diverse kinds of refrigerant mixtures to develop new refrigerants to lessen the use of undesirable substances in refrigeration systems. It has since been proposed that the addition of R134a into a hydrocarbon mixture improves the safety of the refrigerant. In this study, the effect of R134a addition into a hydrocarbon mixture was investigated in relation to the heat transfer performance of the flow boiling of R290/R600a 50%/50% and R134a/R290/R600a 40%/30%/30% by mass in a coolant-cooled horizontal helical evaporation coil. The same R134a hermetic reciprocating compressor was used. The heat transfer performance results of the mixtures were compared with those of R134a. Using R134a/R290/R600a provides favourable conditions to reduce energy consumption. The charge amount is lower than the required amount of R134a. The hydrocarbons reduce the levels of pressure on the evaporator, consequently enhancing the heat transfer rate and positively influencing the overall performance.