Selection Methodology of Potential Sensible Thermal Energy Storage Materials for Medium Temperature Applications

Abstract

Thermal energy storage (TES) component improves the revenue of a concentrating solar power (CSP) plant by allowing more heat to be stored and making the electric energy available during the absence of sunlight. The heat can be stored in three ways (sensible, latent, or thermochemical). The present work aims to identify and select cost-effective sensible TES systems suitable for the medium temperature range (100-300 °C) applications (e.g. Fresnel CSP plants, industrial waste heat recovery, etc.). Based on a literature review, a selection methodology is developed to select potential candidate solid TES media (e.g. natural rock, concrete, sand, etc. ) as filler material in direct or indirect contact with thermal oil, which is used generally as heat transfer fluid (HTF) for this temperature range. The main criteria and steps of this selection methodology are identified and they take into account the different decisive storage properties as thermo-physical and mechanical properties of the solid media. Finally, the potential candidate TES materials are identified for the targeted application and further indoor experimental investigations are briefly presented.