Towards sustainable HVAC systems: Comparative analysis of R22 and R290 with finned-tube and microchannel condensers

Energy efficiency and environmental sustainability are critical in the transformation of modern air conditioning systems, especially in light of global climate goals and the phasing out of high-GWP refrigerants. This study features an experimental performance evaluation of a residential split-type air conditioning unit retrofitted with a microchannel condenser and charged with the natural refrigerant R290, offering a viable replacement for conventional hydrochlorofluorocarbon refrigerant based systems. Four configurations were examined: R22 and R290 refrigerants each with both finned-tube and microchannel condensers. The key performance parameters including coefficient of performance, compressor work, refrigerating effect, and heat rejection were recorded and analysed. The integrated assessment reveals that the R290-microchannel system achieved the maximum efficiency, with COP improvements up to 25 %, compressor work reductions of up to 23 %, and refrigeration effect enhancements up to 24 % compared to the baseline system. Moreover, the microchannel condenser was found to be 38 % lighter than the finned-tube counterpart for the same face area, promoting system compactness and reduced material use. These findings underscore the synergistic benefits of combining natural refrigerants with advanced heat exchanger designs, supporting the sustainable development goals namely SDG 7, 9, 11, 12 and 13. The results demonstrate a clear pathway for environmentally friendly and energy-efficient retrofitting solutions in residential and commercial air conditioning sectors.