Calorimetric study of the mixtures PE/NPG and PG/NPG

Abstract The polyalcohols neopentylglycol (NPG), pentaglycerine (PG) and pentaerythritol (PE) present reversible solid-solid transitions with properties (enthalpy change, temperature) that make them suitable for energy storage at relatively low temperatures (40–180°C). In this article we present a calorimetric study of the binary mixtures PE/NPG and PG/NPG. We have analyzed the dependence of the enthalpy changes and the transition temperatures on the concentration of the compounds, and the effect of cycling on the transition characteristics. Our results indicate that, when the concentration of the minoritary compound in the mixture is less than about 40% there is a total inhibition of the transition corresponding to this compound. We observe that the transition from crystalline solid to plastic crystal corresponding to NPG can be advanced in temperature by addition of PE or PG. This fact increases the possibilities of the utilization of these mixtures for solar energy storage.