Studies of binary mixtures of hexadecane and polyethylene glycol distearate for passive solar thermal storage

Abstract

Solid-liquid phase transition have been studied in hexadecane, poly(ethylene glycol-400) distearate and in their mixtures, by DSC measurements. The mixture, denoted as PCM 5, containing 76 wt % of poly(ethylene glycol-400) exhibited the phase transition in the narrow temperature range, 22.5-25 °C. The mixture was shown to be suitable for impregnation of various passive solar wallboard materials. Thermal storage capacity in impregnated brick, plaster and "Tarolit" (mineralized wood filings) was determined. The most promising storage capacity amounting 50-53 kJ/kg was obtained in plaster and "Tarolit" impregnated with PCM 5 in the temperature range 22-26 °C. The value of the available stored energy in walls impregnated with PCM 5 exceeds by far all known systems studied so far.