Preparation of Na2HPO4⋅12H2O-based composite PCM and its application in air insulated box

Abstract In order to provide continuous supply for succeeding application, abundant electricity energy and solar energy can be stored by means of thermal storage technology. In the present paper, the heat energy storage/exothermic tests are conducted to evaluate the performance of thermal energy storage and release of electricity energy in the self – designed heat storage box equipped with the composite phase change material (PCM), the delivery of heat to surrounding environment is through an air blower directly. The composite PCM consisting of Na2HPO4⋅12H2O and Na3PO4⋅12H2O at the ratio of 7:3 is used to carry out the tests, which is with stable solidification property. Following results are obtained from this research: (1) The solidification temperature of the composite PCM is 33.4 °C with reduced supercooling degree of 2.6 °C; (2) The is phase change exothermic enthalpy value of the composite PCM is 178.02 J/g; (3) The self – designed “peak load shifting” heat storage equipment for electricity energy is with the energy exchange efficiency of 89.59%. The achievements of this research show the applicability of the thermal storage technology by means of the composite PCM.