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• The presence of PCMs reduces temperature fluctuations and heat transfer to the room. • Performing sensitivity analysis for HTR based on variation in properties. • Thermal conductivity of PCM plays most significant role in selecting the appropriate PCM. • For equal thermal conductivity, closer melting point to room temperature is preferred. • When PCM is closer to the exterior, a larger portion of it melts, HTR is greater. Passive latent heat thermal energy storage approach incorporating phase change materials (PCM) is a brilliant technique to tackle high energy consumption issue in buildings. This paper investigated the thermal performance of the conventional walls of buildings in Isfahan, Iran with the inclusion of thirteen different phase change materials. The studied base wall was composed of plaster (2 cm), clay brick (15 cm), and cement (3 cm). The effect of PCM position inside the wall on the heat transfer was assessed in two scenarios, namely: close to the interior and close to exterior. The nonlinear governing equations were solved using the finite volume method. The results show that the performance of PCM-based wall is strongly influenced by the thermal conductivity, phase-change enthalpy and melting temperature of PCM. A PCM can more efficiently reduce the heat transfer to the interior space in case it has a lower thermal conductivity, has a higher latent heat of phase-change, and its phase-change temperature is closer to the room temperature. Moreover, the thermal conductivity has priority over other PCM thermophysical properties. The lower PCM thermal conductivity leads to transfer the lower amount of heat to the interior space. A two-fold increase in the thickness of the PCM leads to less than a twofold reduction in the heat transfer. Among the studied PCMs, the heat transfer reduction by Enerciel 22 was within the range 15.6–47.6%, while this range was 2–7.8% for CaC l 2. 6 H 2 O. [ABSTRACT FROM AUTHOR]

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. • Efficiency enhancement of a household refrigerator has been studied. • Eutectic phase change materials with cascade configuration have been used in the system. • The compressor off-time of the novel system lowered significantly. • Energy consumption of the refrigerator with single PCM was reduced by 8%. • Further energy consumption reduction up to 13% has been achieved in cascade configuration. [ABSTRACT FROM AUTHOR]