(392a) Vermiculite/MgSO4 Composite for Thermal Energy Storage

Thermal energy storage using exothermic water vapor adsorption process is a novel technology to store thermal energy from the renewable energy sources and utilizing it later when it is needed. The main advantage of this technology is that it does not use any toxic chemicals, and it is pollution free. A recyclable mineral, vermiculite is a good adsorbent for thermal energy storage as it has high water sorption capacity. In this paper, water-vapour was used as the adsorbate and vermiculite/MgSO₄ composite was used as the adsorbent. The thermal energy storage density of the composite was determined to be 189 kWh/m³ at an inlet relative humidity (RH) of 90 % after regeneration at 120℃ using a lab scale thermal energy storage setup. Vermiculite itself had a very low energy storage density at 14 kWh/m³ for 90%RH at the inlet after regeneration at 120℃, which showed that the composite turned out to be a good candidate in enhancing the energy storage density of vermiculite. The composite had a cost of 1.84 CAD/kWh, which showed that it is a cost effective material.