Preparation and heat storage/release behavior of latent heat storage gypsum-based building materials

A new method to manufacture gypsum-based building materials with high latent heat storage capability is described. When expanded graphite is used as the adsorption medium for butyl stearate, an organic/inorganic phase-change composite is formed. This composite can be mixed with gypsum to manufacture a latent heat storage gypsum-based building material. Differential scanning calorimetry (DSC) test results indicate that the phase-change enthalpy value of this composite is similar to that of pure butyl stearate and that it therefore displays good thermophysical properties. We found that a mixture of gypsum with this composite should contain no more than 5 % of the latter to maintain the workability of the paste. The hardened gypsum-composite material exhibits some defects in the interface between the phase-change composite and the gypsum, but these do not seriously affect the strength of the gypsum product. The results of a temperature cycle test illustrate that gypsum containing 5 % phase-change composite can deliver high-performance heat storage/release. This characteristic of the composite will improve the inertia of ambient temperature fluctuations, making it applicable as a new building product that will conserve energy.