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Photovoltaic technology plays a crucial role in harnessing renewable energy. While photovoltaic panels directly convert solar energy into electricity, more than 50% of solar radiation is lost as waste heat, diminishing the overall efficiency of the panels. This study reviews various cooling technologies for photovoltaic systems, focusing on the use of phase change materials for cooling in photovoltaic systems. Phase change materials, known for their high latent heat capacity, are extensively used in thermal energy storage applications. Incorporating phase change materials in photovoltaic systems can increase thermal storage potential by 30–50% compared to conventional systems, leading to a 70% extension in heat storage duration and various levels of enhanced power output. The main purpose of the article is to review the advantages and disadvantages of various technologies, determine the research direction of phase change materials for cooling systems in photovoltaics, and ensure the reliability of this technology. [ABSTRACT FROM AUTHOR]

The adsorption desalination and cooling system (ADCS), a promising technology for alleviating water scarcity, requires adsorbents with high performance, low cost, and low energy consumption. Enhancing the operating efficiency and minimizing the energy consumption of the system entails improving the adsorption performance and thermal conductivity of adsorbents. In this study, nanoparticles (NP) embedded silica gel (SG) composite adsorbents with CaCl2 were synthesized for use in ADCS. The effects of nano-Fe, nano-Cu and carbon nanotubes (CNT) as SG thermal conductivity enhancers were thoroughly compared through microscopic properties, thermal properties and adsorption properties. The experimental results show that SG/CNT/CaCl2 composite performs the largest specific surface area and pore volume of 180.72 m2 g−1 and 0.13 cm3 g−1. Scanning electron microscopy (SEM), accelerated surface area and porosimetry (ASAP) and constant thermal analyzer (TCA) were used to characterize the various performance of the enhanced adsorbents comprehensively. SG/CNT/CaCl2 sample exhibits high thermal conductivity and thermal diffusion coefficient, measuring as high as 0.664 W m−1 K−1 and 0.701 × 10−6 m2 s−1, respectively. Based on dynamic water adsorption performance tests, the SG/CNT/CaCl2 composite had an adsorption capacity of 0.665 g g−1, five times higher than SG. The composite's adsorption capacity and thermal conductivity did not decline significantly during cycling, indicating a high degree of sustainability. Therefore, these results imply that the nanoparticles-embedded SG/CaCl2 adsorbent with excellent integrated properties has promising prospects in adsorption desalination systems. Highlights: The silica gel/nanoparticles composites adsorbent with CaCl2 are synthesized. The thermal conductivity of silica gel/CNT/CaCl2 composite is 0.664 W m−1 K−1. The adsorption capacity for composite with CNT/CaCl2 is five times higher than silica gel. [ABSTRACT FROM AUTHOR]

In order to solve the phase separation problem of Na2S2O3·5H2O–CH3COONa·3H2O PCM (phase change material), sodium carboxymethyl cellulose (CMC), hydroxyethyl cellulose (HEC), xanthan gum (XG), sodium polyacrylate (PAAS) and polyacrylamide (PAM) were selected as additives. The effects of different proportions of the above thickeners on the supercooling degree, phase separation, phase change temperature and latent heat of Na2S2O3·5H2O–CH3COONa·3H2O system were studied by using the cooling curve and DSC, so as to screen the best thickener for eutectic PCM. The experimental results show that CMC, XG and PAAS can eliminate the phase separation of Na2S2O3·5H2O–CH3COONa·3H2O. Among them, the optimal ratio of CMC, XG and PAAS is 3 mass%, 3 mass% and 1 mass%, respectively. From the perspective of heat storage performance, PAAS is the optimal thickener for Na2S2O3·5H2O–CH3COONa·3H2O. The phase change temperature is 40.5 °C. The subcooling degree is about 14.7 °C, and the latent heat is about 221 J g−1. The melting time is 15 min. Only PAAS can make Na2S2O3·5H2O–CH3COONa·3H2O eutectic PCM completely exothermic at room temperature, which can not only play the role of thickener to eliminate phase separation, but also is a nucleating agent. After 100 melting-solidification cycles, the change rate of latent heat value was only 5%, and the change rate of phase transition temperature was less than 1%. Considering heat storage performance and cyclic stability, PAAS is the optimal thickener for Na2S2O3·5H2O–CH3COONa·3H2O PCM. [ABSTRACT FROM AUTHOR]