Abstract:
The world is conscious about contribution to global warming from refrigeration and air-conditioning sector. A search is ongoing for energy-efficient refrigeration systems and environment-friendly refrigerants. Cascade refrigeration system (CRS) has been recognized as a prospective technology to improve energy efficiency while meeting multi-target temperatures. This study investigates various environment-friendly refrigerants for seafood processing and storage application having multi-target temperature in a warm climate. Fourteen potential low GWP pure fluids and one popularly used blend are identified as refrigerants based on literature survey. Out of these, six refrigerants (R41, R170, R1270, R404A, CO2, and N2O) were earmarked for the low-temperature circuit and ten (R152a, R161, RE170, R290, R1270, R1225ye(Z), R1234yf, R1234ze(E), R1243zf, and NH3) for the high-temperature circuit of the CRS. Suitable modelling and simulation techniques were employed to investigate the performance parameters namely COP, annual energy consumption, total equivalent warming impact, compressor volumetric displacement, compressor discharge temperature, and compression ratio. The refrigerant pair RE170-R1270 showed the best overall COP and also the lowest total equivalent CO2 emission for the application. NH3-CO2, the most studied refrigerant pair in literature, showed marginally lower COP; however, it has the lowest compressor volumetric displacement leading to a compact system with the minimum refrigerant charge. NH3 exhibited a higher compressor discharge temperature in all CRS, which can provide an opportunity for heat recovery. The study is expected to help the policy makers to frame regulations to encourage the use of sustainable refrigerants in the near future