Investigation on the chlorine freeHFC refrigerants which have bothadvantages of HFC and HCFC. So the new study on blending of hydroflurocarbontakes place and new gases are formed such as R507A and R417a. All the Blend mixtures are not the solution for thereplacement of existing refrigerantbecause GWP of the mixed refrigerant should be less than present usingrefrigerant. Among the blend mixtures, R417a had given the better results andhad capacity to replace the present using R22 applications. R147a utilises lesspower consumption than R22 where the experiment carried on the same apparatusand same operating conditions. Refrigerant R417a comprises of R125, R134 andR600.BinitKumar Jha has done the theoretical study between the eco friendly R600arefrigerant and the widely used R134a refrigerant and observed that thedischarge pressure of R600 is less thanthat of R134a and the refrigerant effect and the coefficient of performance iscomparatively high for R600a than R134a.
AdilF. Momin and Manish H. Attal carried outexperimental tests on the domestic refrigerator using phase change materials with R290/R600a blend as a refrigerant,while the PCM used is ethylene glycol, coated on the back side of theevaporator. Addition of PCM enhance the heat transfer and increases theevaporator temperature.
Thermal energy stored in the PCM is used during the offcycles which benefits for the continuous refrigeration operation.. This lead toincrease in the COP and decrease in the refrigerant cycling time.Researchto find a replacement refrigerant R134a have been carried out by severalprevious researchers. Prayudi and Roswati Nurhasanah also had a performanceanalysis on the R600a and R134a refrigerants with the subcooling effect usingthe liquid suction heat exchangers with cooling load. Cooling load variationsare done by opening the valve at different positions. There is no impact on thecompressor work due to cooling load and compressor work increases with thesubcooling effect. Greater the sub cooling temperature, greater the temperaturedrop in the evaporator and R600a is giving better results when compared toR134a.
Prayudi Suparmin has done aexperimental analysis on the different refrigerants for different degree ofsubcooling. He had used the liquid suction heat exchanger for the differentdegree of subcooling and said that on subcooling the refrigerant which tends toprevent the flash gas formation at the throttle valve. From the experiment heshowed, the effectiveness of LSHE increases with the increase in degree ofsubcooling. He showed the mixture of R290 and R600a in the ratio of 50:50 in arefrigeration system is having the highest effectiveness of LSHE when comparedto other refrigerants.