Development and Performance Evaluation of High Temperature Concrete for Thermal Energy Storage for Solar Power Generation
Thermal energy can be stored by the mechanism of sensible or latent heat or heat from chemical reactions. Sensible heat is the means of storing energy by increasing the temperature of the solid or liquid. Since the concrete as media cost per kWhthermal is $1, this seems to be a very economical material to be used as a TES. This research is focused on extending the concrete TES system for higher temperatures (500 °C to 600 °C) and increasing the heat transfer performance using novel construction techniques. To store heat at high temperature special concretes are developed and tested for its performance. The storage capacity costs of the developed concrete is in the range of $0.91-$3.02/kWhthermal. Two different storage methods are investigated. In the first one heat is transported using molten slat through a stainless steel tube and heat is transported into concrete block through diffusion. The cost of the system is higher than the targeted DOE goal of $15/kWhthermal. The increase in cost of the system is due to stainless steel tube to transfer the heat from molten salt to the concrete blocks.The other method is a one-tank thermocline system in which both the hot and cold fluid occupy the same tank resulting in reduced storage tank volume. In this model, heated molten salt enters the top of the tank which contains a packed bed of quartzite rock and silica sand as the thermal energy storage (TES) medium. The single-tank storage system uses about half the salt that is required by the two-tank system for a required storage capacity. This amounts to a significant reduction in the cost of the storage system. The single tank alternative has also been proven to be cheaper than the option which uses large concrete modules with embedded heat exchangers. Using computer models optimum dimensions are determined to have an round trip efficiency of 84%. Additionally, the cost of the structured concrete thermocline configuration provides the TES capacity cost of $33.80$/kWhthermal compared with $30.04/kWhthermal for a packed-bed thermocline (PBTC) configuration and $46.11/kWhthermal for a two-tank liquid configuration.
- Research Organization:
- Univ. of Arkansas, Fayetteville, AR (United States)
- Sponsoring Organization:
- USDOE EE Office of Solar Energy Technology (EE-2A)
- DOE Contract Number:
- FG36-08GO18147
- OSTI ID:
- 1072014
- Report Number(s):
- DOE-UARK-18147
- Country of Publication:
- United States
- Language:
- English
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