Abstract:

In this study, the performances of refrigerant mixtures in ideal vapor compression refrigeration cycles were investigated theoretically. By choosing six different refrigerants as dimethyl ether (DME), R125, R134a, R143a, R152a, and R32, eleven different refrigerant mixtures were handled. Each mixture's vapor compression refrigeration cycle performances were evaluated according to three different condenser outlet temperatures and nine different mass fractions (90%/10% to 10%/90%). To examine the thermodynamic performance of refrigerant mixtures, constant evaporator outlet temperature (-10 oC) and different constant condenser outlet temperatures (20 oC, 25 oC, and 30 oC) were determined. According to the evaluated refrigerant mixtures, the COPR values of the refrigerant mixtures containing DME were calculated as the highest among all the mixtures. In the mixtures containing DME, it was observed that the COPR values decreased as the mass percentage of DME decreased. The COPR values are calculated in the range of 3.66-5.70 for the R134a/R32 mixture, 3.82-5.81 for the R134a/R143a mixture, 3.97-5.99 for the R143a/R32 mixture, 3.83-5.83 for the R125/R143a mixture, 3.86-5.98 for the R125/R32 mixture, 4.34-6.24 for R134a/R152a mixture, 3.78-5.81 for R143a/R152a mixture, 3.57-5.55 for R152a/R32 mixture, 3.40-6.28 for DME/R125 mixture, 4.34-6.27 for DME/R134a mixture and 3.59-5.82 for the DME/R32 mixture. When the pure forms and mixtures of the refrigerants discussed in the study are compared, it is seen that the pure DME and R32 gases are slightly more performant than the gas mixtures examined. The R125 gas mixture shows a higher performance than the pure R125 gas, and the R134a and R143a mixtures show slightly higher performance than the pure gas forms. Finally, the specific energies of pure refrigerants and refrigerant mixtures were calculated within the scope of the study. DME has the highest specific energy among pure refrigerants, while DME/R32 mixture has the highest specific energy among refrigerant mixtures.

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