Energy management of a household refrigerator using eutectic environmental friendly PCMs in a cascaded condition

Abstract

In this study, a series of experimental runs performed under different conditions in order to evaluate the effectiveness of a household refrigerator. Two eutectic phase change materials (PCMs) arranged in a cascade configuration have been tested on the performance of the system. The PCMs were placed on the back-side of the wire-and-tube condenser in a decreasing order of their melting temperatures along the refrigerant flow direction to achieve a high heat transfer rate and to reduce energy consumption. The operating characteristics of the novel refrigerator were studied and compared with the results of a refrigerator equipped with a single PCM and two ordinary refrigerators with and without measurement packages (M-packs). All the tests have been performed in standard condition in Philver Company in Tehran, Iran. For the novel refrigerator, the temperature of the condenser surface significantly decreased, which led to a lower condensing temperature during the refrigeration cycle and improved the coefficient of performance (COP). Also, the ratio of the on-time to the total experiment time was considerably shorter compared to the refrigerator equipped with a single PCM and two ordinary refrigerators. According to the results, integration of two different PCMs on the condenser surface in a cascade arrangement decreases the compressor work time percentage from 32.7 to 27.6, while this parameter was decreased to 29.6 with a single PCM. Finally, the energy consumption was reduced by 13% in the novel refrigerator whereas it was only reduced by 8% in the refrigerator equipped with a single PCM.