Abstract
In this article, R1234ze(E), R152a, and three mixtures M1, M2, and M3 composed of R152a and R1234ze(E) (in the ratio of 60:40, 50:50, and 40:60, by mass, respectively) as drop-in replacements of R134a in vapor compression system were theoretically analyzed. The performance of the vapor compression system was compared in terms of compressor discharge temperature, volumetric cooling capacity, cooling capacity, compressor power consumption, and coefficient of performance. The results showed that R152a had better coefficient of performance as well as nearly equal volumetric cooling capacity and cooling capacity compared to R134a; however, flammable R152a running with high compressor discharge temperature was restricted. Cooling capacity of R1234ze(E) was far lower than that of R134a. M2 was selected as the best alternative for R134a. Volumetric cooling capacity of M2 and R134a was similar so that M2 can be used in R134a vapor compressor system without modifying compressor. Coefficient of performance of M2 was higher than that of R134a by about 3% with 7% lower cooling capacity and 10% lower compressor power consumption. Compressor discharge temperature of M2 was higher than that of R134a by about 2°C–5°C. It was concluded that M2 can primely be an energy conservation and environmental protection alternative to R134a in vapor compression system.
Highlights
During 1900s, chlorofluorocarbons (CFCs) and hydro chlorofluorocarbons (HCFCs) with high ozone depletion potential (ODP) and global warming potential (GWP) were extensively used in domestic refrigeration and mobile air conditioning systems
It was obtained that the mass flow rate of R1234ze(E), M3, M2, M1, and R152a were lower than that of R134a by about 19%, 24%, 27%, 30%, and 41%, respectively, at a temperature range between 220°C to 10°C due to lower vapor density
R152a performs better coefficient of performance (COP) as well as nearly equal volumetric cooling capacity and cooling capacity compared to R134a, which make it the best replacement of R134a; R152a with the flammability limits listed as 5.1%–17.1%22 running high compressor discharge temperature causes high insecurity in vapor compression system
Summary
During 1900s, chlorofluorocarbons (CFCs) and hydro chlorofluorocarbons (HCFCs) with high ozone depletion potential (ODP) and global warming potential (GWP) were extensively used in domestic refrigeration and mobile air conditioning systems. CFCs and HCFCs should be banned according to the Montreal Protocol.[1] R134a considered as a promising alternative refrigerant to CFCs and HCFCs is widely used in domestic refrigerator and mobile air conditioner. Its ODP value is zero, but GWP value is high with 1300. R134a is main compound of green house gas emission according to the Kyoto Protocol.[2] Fluorinated gases with GWP value higher than 150 should be banned in new model automobiles air conditioner from 1 January 2011 and all new automobiles air conditioner since 1 January 2017 according to the rules of F-gas.[3] In 2014, the European Union revised F-gas[4] contained that
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