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In pursuing sustainable refrigeration solutions, integrating phase change materials (PCMs) within sun-powered refrigerators emerges as a promising avenue to mitigate challenges associated with sun radiation intermittency and reliance on large battery systems. This paper comprehensively examines incorporating PCMs into sun-powered refrigerators to address critical issues hindering the widespread adoption of solar refrigeration technologies, particularly in medicine and perishable goods. The primary objective of this study is to assess the efficacy of PCM integration in achieving grid disconnection and enabling autonomous operation of sun-powered refrigerators. Through experimentation and data analysis, our findings elucidate the transformative impact of PCM utilization on the performance and sustainability of solar refrigeration systems. Key outcomes from the experimental trials demonstrate that incorporating PCMs facilitates prolonged operation of sun-powered refrigerators, even without direct sunlight. By harnessing the thermal storage capabilities of PCMs, the refrigeration unit achieves grid independence, thereby mitigating reliance on conventional power sources and large battery configurations. In conclusion, integrating phase change materials is pivotal to achieving energy autonomy and sustainability in sun-powered refrigeration systems. Through collaborative efforts and continued innovation, PCM-enabled refrigeration technologies hold immense promise in revolutionizing cold chain logistics and enhancing global access to vital medical resources and foodstuffs. [ABSTRACT FROM AUTHOR]

Electrocaloric refrigeration shows potential as a viable alternative to vapor-compression and/or thermo-electric refrigeration. One of the main challenges that need to be addressed in electrocaloric technology is the fatigue behavior of electrocaloric materials, in terms of both structural and functional aspects. Here, a comprehensive evaluation of the fatigue behavior of the 0.9Pb(Mg1/3Nb2/3)O3–0.1PbTiO3 (PMN-10PT) bulk relaxor ferroelectric (or shortly relaxor) ceramic at room temperature is performed. First, the temperature-change dependence on the slew rate was studied. It is shown that the adiabatic conditions are well approached at the slew rate above 1 kV s−1, at which the adiabatic temperature change of 1.3 K was measured at the electric field change of 90 kV cm−1. Then, the durability limits (i.e., the fatigue life) of ten PMN-10PT samples were investigated during unipolar electric field cycling. The results showed that the material could withstand up to 106 cycles at the electric field change of 90 kV cm−1 with only minor degradation of the functional properties (less than 5% of the maximum adiabatic temperature change). Hence, PMN-10PT can be considered as a promising material for use in an electrocaloric cooling device, but some critical issues that caused premature failure of several samples would need to be further addressed and improved. [ABSTRACT FROM AUTHOR]

This study presents an experimental investigation conducted on a refrigerator powered by direct current and composed of a 166L cabinet, a condenser embedded in the external wall of the compartment (hot-wall), an internal static evaporator, a hermetic variable speed compressor. The refrigerant fluid used is the R290a, a natural fluid. By placing the refrigerator in a temperature-controlled environment, four external temperatures have experimented: 22, 25, 29 and 32 °C. Three different temperature setpoints have been set for each temperature: -5, -10, -20 °C. In this way, 12 test conditions were defined, and each of them was repeated by imposing four different compressor rotation speeds: 2000, 2500, 3000, 3500 rpm. The set of tests allowed to identify for each operating condition the optimal number of operating revolutions aimed at minimising the energy consumption of the analysed device.