Simulation of fractionation of low GWP zeotropic refrigerants on modular refrigeration unit performance after leak events.

Fractionation of zeotropic mixtures due to leaks and recharges was simulated to ascertain the effect of composition changes on the performance of R-404A vapor compression cycles with low global warming potential replacements. Fractionation effects have been examined similarly in the past, but not for the specific replacement of R-404A with R-450A and R-456A. System coefficient of performance (COP) was found to be improved by 3.3 and 3.7% with R-450A and R-456A before fractionation. Both adiabatic leaks and recharges or isothermal leaks were found to reduce COP by approximately 0%. While R-404A also showed nearly no change after isothermal leaks, it was found to have a 1% decrease in COP after 3 leaks and recharges. The initial results of this study suggest that R-450A and R-456A may be favorable replacements for R-404a due to decreased fractionation, minorly better performance and lower global warming potential.