Optimized air-to-refrigerant heat exchanger with low-GWP refrigerants.

This paper presents an analytical evaluation of the performance of low-GWP refrigerants in a finned-tube evaporator used for residential cooling applications. The study employed an evolutionary-computation optimization module to examine the effect of a refrigerant circuitry design on performance of twelve alternative refrigerants for R22 and R410A. The study showed that high-pressure fluids benefited most from refrigerant circuitry optimization, with R744 achieving a capacity increase of over 13 %. Among lower-pressure fluids, the capacity of an R717 evaporator increased by over 10 %. The effect of optimized refrigerant circuitries on the system performance was estimated. The results show that zeotropic blends with a large temperature glide are particularly sensitive to the refrigerant circuitry and may suffer significant performance degradation in heat exchangers with improper design.