| Popis: |
Production and use of R12 and other chlorofluorocarbon refrigerants will be prohibited completely all over the world in the year 2010 due to their harmful effects on the earth’s protective ozone layer. Therefore, in this study, the exergetic performance of a domestic refrigerator using two environment-friendly refrigerants (R134a and R152a) was investigated and compared with the performance of the system when R12 (an ozone depleting refrigerant) was used. The effects of evaporator temperature on the coefficient of performance (COP), exergy flow destruction, exergetic efficiency and efficiency defect in the four major components of the cycle for R12, R134a and R152a were experimentally investigated. The results obtained showed that the average COP of R152a was very close to that of R12 with only 1.4% reduction, while 18.2% reduction was obtained for R134a in comparison with that of R12. The highest average exergetic efficiency of the system (41.5%) was obtained using R152a at evaporator temperature of -3.0oC. The overall efficiency defect in the refrigeration cycle working with R152a is consistently better (lower) than those of R12 and R134a. Generally, R152a performed better than R134a in terms of COP, exergetic efficiency and efficiency defect as R12 substitute in domestic refrigeration system. |
