Selection of phase change materials for high temperature latent heat thermal energy storage for concentrated solar power plants

Abstract

Concentrated Solar Power (CSP) is one of the most promising options among emerging renewable energy technologies. Thermal energy storage can be incorporated into CSP plants to improve dispatchability. Thus, the development of high-temperature Thermal Energy Storage (TES) materials is essential to enhance the performance of CSP plants. Phase Change Materials (PCM) show favourable characteristics to be used as the working material in this application. This paper addresses the selection of appropriate storage materials that have desirable properties for thermal energy storage in CSP applications, considering the cost and volume per unit of thermal energy storage. A three-stage screening process based on melting temperature, latent heat of fusion, cost, thermal conductivity and storage volume criteria was used to select the most economical and thermo-physically feasible materials from a list of 25 materials. Accordingly, Na2CO 3 +Li 2 CO 3 (56:44), Li 2 CO3+K2CO 3 (2S:72), Li 2 CO3+K2CO 3 (35:65), NaF+KF+K2CO 3 (17:21:62), LiCO 3 +Na2CO3+K2CO 3 (20:60:20), Li 2 CO 3 +Na2CO3+K2CO 3 (22:16:62), K 2 CO 3 +Na2CO 3 (51:49) S PCMs were selected as the best materials to develop high temperature TES for CSP plants. Using these PCMs as storage materials, cost-effective TES can be developed to deliver technical and economic benefits.