Long-term stability of sensible thermal energy storage materials developed from demolition wastes interacting with hot heat transfer fluid

Abstract

Packed-bed thermal energy storage (TES) system filled with low cost and sustainable sensible thermal energy storage material (STESM) is a promising option for medium-high temperature applications. STESM developed from demolition wastes are eco-innovative and compatible with circular economy. They can be used in solar heat industrial applications up to 750°C. One of the main concerns that should be taken into consideration is the stability of STESM developed from demolition wastes in direct contact with hot heat transfer fluids (HTFs). In this study, thermal and mechanical stability of STESM developed from demolition waste were investigated using repeated heating and cooling cycles in Therminol 66 synthetic oil as HTF at 150°C for up to 500 hours. The characterization results before and after thermal cycling showed that new STESM developed from demolition wastes is thermally and mechanically stable. Also, strong oil penetration into the STESM samples improved the porosity, strength, and specific heat capacity. The specific heat capacity and mechanical strength values increased from 1330 to 1490 J/kgC and from 4 to 6 MPa, respectively. These results suggest that STESM samples developed from demolition waste can be used reliably in solar heat industrial applications for long term.