Thermal-economic-environmental analysis on household refrigerator using a variable displacement compressor and low-GWP refrigerants

Variable displacement compressor technology can achieve high steady-state efficiency, non-start/off operation thus high seasonal efficiency and capacity modulation. A comprehensive thermal-economic-environmental analysis of a household refrigerator with variable displacement compressor using three refrigerants (R134a, R152a and R1234yf) was presented using CoP and normalized CoP, set-up and running cost and Life Cycle Climate Performance, respectively. The results indicate that with the application of variable displacement technology, the compressor stroke can be tuned in response to heat load so that the power consumption is reduced thus the running cost and CO₂ emissions. When the compressor stroke using R134a drops from 13 mm to 10 mm, the power consumption, total cost and life cycle CO₂ emissions decrease by 86.3%, 56.7% and 59.9%, respectively. Running cost accounts for 89% of the total cost while indirect emissions accounts for 98% of the total CO₂ emissions. Replacement of R134a by R152a will decrease the CoP by 10% but also reduce the cost and CO₂ emissions by 5% and 8.6% respectively. This is comparable to increasing the R134a system CoP by 0.9. It is indicated that by adopting variable displacement technology, more CO₂ emissions could be reduced given that part load represents over 80% of operating hours for refrigerators.