Energetic and Exergetic Performance of Solar-Assisted Direct Expansion Air-Conditioning System with Low-GWP Refrigerants in Different Climate Locations

Abstract

This study aims to assess an air-conditioning cycle designed to make use of hydrofluoroolefins (HFOs) within a direct expansion air-conditioning system combined with a solar energy source. An energy–exergy analysis was applied in order (i) to examine which HFO working fluid is more efficient and (ii) to draw a comparative analysis between the proposed cycle and the conventional air-conditioning cycle. To achieve this, a simulation has been devised to determine the coefficient of performance (COP), exergetic efficiency, and total irreversibility for three HFOs. These HFO fluids are R1234yf, R1234ze(E), and R1233zd(E) which were compared to R410A and R134a. System operating conditions, such as the impact of storage tank exit temperatures on compressor discharge temperatures and condenser surface augmentation, were also taken into consideration and are being investigated. Results of the study indicated that the use of evacuated tube solar collector within a vapor compression air-conditioning system can improve performance by 15–56% and save 5–40% in electrical energy consumption. The study also concludes that HFOs are excellent alternatives for R410A and R134a. Accordingly, the total irreversibility of the proposed cycle with R1234yf, R1234ze(E) and R1233zd(E) is less than that of R410A and R134a.