Conversion of electric power to heat and from the stored heat back to power is the energy storage concept that allows high temperature and high-capacity accumulation (hundreds of MWh stored in the heat). Combination of the high temperature heat storage with use of the sCO2 energy conversion cycle may provide highly efficient and very flexible energy storage system. An aluminum alloy was identified as a suitable accumulation material for the latent heat storage due to its high latent heat, appropriate melting point (577°C) and acceptable price. The energy storage system with Al-Si12 alloy as the heat storage material and the sCO2 conversion cycle is being developed at CVR.

In this paper, design of a mock-up of the storage tank with the aluminum alloy, an electrical heating system and a sCO2 heat exchanger will be presented. The storage tank with capacity of 300 kWht will be fabricated, connected to the sCO2 experimental loop of CVR and operated at the relevant conditions to demonstrate capabilities of the energy storage concept. A thermal computational model that was developed to support design and optimization of the sCO2/metal heat exchanger will be also presented. Based on the computational model results, feasibility of this concept for the high capacity energy storage will be discussed.