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Abstract: Composite phase change materials (PCM) for latent heat thermal energy storage were made by mixing two different kinds of exfoliated graphite nanoplatelets (xGnP-1 and xGnP-15) into paraffin wax. Direct casting and two roll milling were used to prepare samples. The investigation on the thermal and electrical conductivity of nanocomposites with these two nanoplatelets was performed. Higher thermal conductivity of composite PCM can be achieved with nanofillers of larger aspect ratio, better orientation and lower interface density. The thermal physical properties of the nanocomposites were investigated by differential scanning calorimetry and thermal gravimetric analysis. It was found that the latent heat of the nanocomposites was not adversely affected by the presence of xGnP nanoplatelets and the thermal stability improved. [Copyright &y& Elsevier]

Abstract: Melting of the binary mixture system of tetradecane and hexadecane in Differential Scanning Calorimetry (DSC) cell has been investigated experimentally and numerically. Different concentrations of tetradecane–hexadecane paraffin mixture were studied. It is found that the phase change process of the binary mixture takes place over a temperature range and the temperature range depends on both the heating rate and the mixture composition. The proposed study shows also that for the same concentration of tetradecane and using various heating rates, we will be able to predict the solidus and liquidus temperature of the binary mixture from DSC curves. [ABSTRACT FROM AUTHOR]

Abstract: Oleochemical carbonates are biobased materials that were readily prepared through a carbonate interchange reaction between renewable C10–C18 fatty alcohols and dimethyl or diethyl carbonate in the presence of a catalyst. These carbonates have various commercial uses in cosmetic, fuel additive, and lubricant applications. Oleochemical carbonates have not been examined for their applicability as phase change materials (PCM). The latent heats of melting and freezing for a series of symmetrical oleochemical carbonates ranging from 21-37 carbon atoms were evaluated to develop a fundamental understanding of the solid–liquid transitions for utilization in thermal energy storage (TES) applications. The phase transitions and associated thermal properties were determined by differential scanning calorimetry (DSC) and thermal gravimetric analysis (TGA). Decyl, dodecyl, tetradecyl, hexadecyl, and octadecyl carbonates had peak melting and freezing points of −2.2, 19.3, 33.7, 44.9, and 51.6 and −6.3, 14.3, 28.7, 40.3, and 46.9°C, respectively. In general, these carbonates exhibited sharp phase transitions and good latent heat properties. The latent heats of melting and freezing for decyl, dodecyl, tetradecyl, hexadecyl, and octadecyl carbonates were 144, 200, 227, 219, and 223 and 146, 199, 229, 215, and 215J/g, respectively. These carbonates represent novel renewable-based PCM chemicals that compliment fatty acids, fatty alcohols, and their fatty acid esters while providing a potentially valuable biobased alternative to paraffin wax and salt hydrate PCM currently dominating the PCM market. [Copyright &y& Elsevier]