U.S. Department of Energy - Energy Efficiency and Renewable Energy

SunShot Initiative

Novel Molten Salts Thermal Energy Storage for Concentrating Solar Power Generation

Alabama logo Graphic of a chart with a line that goes horizontal, up, and horizontal.

DSC plot for the LiNO3-NaNO3-KNO3 ternary system showing the melting temperature.

The University of Alabama, under the Thermal Storage FOA, is developing thermal energy storage (TES) media consisting of low melting point (LMP) molten salt with high TES density for sensible heat storage systems.

Approach

They will conduct detailed tests using a laboratory-scale TES system to:

  • Investigate the thermal performance of the TES
  • Determine the lifecycle of the LMP molten salt system
  • Gauge round-trip efficiency.

The research team is also conducting investigations of corrosion behavior and material selections for a laboratory-scale TES system, as well as studies of recyclability, environmental impact, and economic and cost analysis of the optimized LMP molten salt and TES system.

Innovation

Alabama's LMP molten salt is projected to have the following characteristics compared to current salts:

  • Lower melting point
  • Higher energy density
  • Lower power-generation cost

This program aims to develop a heat transfer fluid/storage medium capable of operating at temperatures >650°C, allowing for operation of higher conversion efficiency turbines. This has the potential to reduce the cost of TES to <$15/kWth and achieve round-trip efficiencies >93%.

Publications, Patents, and Awards

  • D. Mantha, T. Wang, and R. G. Reddy, "Thermodynamic Modeling of Eutectic Point in the LiNO3-NaNO3-KNO3 Ternary System," Journal of Phase Equilibria and Diffusion, 2011.
  • R. G. Reddy, T. Wand, and D. Mantha, "Determination of Thermodynamic Properties of 2KNO3-Mg(NO3)2," Thermochimica Acta, 2011.
  • T. Wang and R. G. Reddy, "Thermal Stability of Low Melting Point NaNO3-NaNO2-KNO3 Ternary Salt for Solar Thermal Energy Storage," SME, CO, 2011.
  • T. Wang, D. Mantha, and R. G. Reddy, "High Thermal Energy Storage Density LiNO3-NaNO3-KNO3-KNO2 Quaternary Molten Salt for Parabolic Trough Solar Power Generation," Energy Technologies and Carbon Dioxide Management, TMS, Warrendale, PA, 2011.
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Quarterly Progress Reports

Learn about other DOE competitive awards for concentrating solar power research that are in progress.