Molten Salt Thermal Energy Storage with Refractory Bricks

Abstract

Molten salt has become the state-of-the-art for high temperature thermal energy storage applications [1]. Since the molten salt itself can make up to 50 % of the total costs for the storage system [2], a substitution with a cost-effective storage material is favorable. This can be achieved by the utilization of single-tank storage systems, where hot and cold molten salt is stratified inside a storage tank. The concept has been demonstrated beforehand with packed bed as storage medium which has some drawbacks due to potential thermomechanical stresses, i.e. so-called ratcheting [3] and the achievable void fraction. A lee-way is the utilization of refractory bricks which can be designed in a suitable way for the specific application, see Figure 1, right. Within the EU-funded project “Newcline”, about 17 tons of refractory bricks have been tested with Solar Salt ranging between 290°C and 560°C. The scope of this work was the investigation of the flow distribution inside the packing.