Performance analysis of induction heated-porous thermochemical energy storage for heat applications in power systems

Abstract

Power flexibility with fast and long-duration heat storage systems is crucial in modern power systems to meet the increasing cooling and heating demand and reduce the gap between renewable intermittent power generation and power demand. The hereby study analyzes the thermal and electrical performances of induction heated-porous thermochemical energy storage for heat applications into microgrids. The induction heating model is built with Maxwell equations for fast induction heat generation and the Surface-to-Surface (S2S) model, P1 approximation and Brinkmann model are adopted for induced and diffused heat transfer in the fluid phase and porous heat storage medium. The effects of the conductive plates’ orientation and location and the coil’s location are investigated. Furthermore, the effect of operating and structural parameters in terms of the electrical power supplied to the coil and the heat transfer coefficient of the coil’s cooling system and reactor insulation are sufficiently examined. Finally, essential parameters for the thermochemical material selection are assessed. It is found that the model with the highest magnitude of the induced magnetic flux passing through the conductive plates has outperformed at 107.57 % the worst model among the developed reactors. Moreover, the temperature distribution of the reactor resulted from the supplied power to the homogenized multi-turn coil and the heating rate at the heat storage material significantly increases with the supplied power. However, increasing the power supplied to the coil leads to higher conductive and convective heat loss resulting in less efficient electrical to heat conversion performance. Thermochemical materials with low emissivity should be preferred as the emissivity could lead to a 13.7 % improvement in the energy efficiency of the reactor. Implementing the proposed model in a microgrid for cooling and heating load improved the energy cost and self-consumption by 31.7 and 8 %, respectively.