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

SunShot Initiative

Encapsulated Phase Change Material in Thermal Storage for Baseload CSP Plants

Terrafore logo Photo of gray balls grouped together.

10 to 15 millimeter capsules provide high heat transfer surface.

Terrafore, under the Baseload CSP FOA, is developing novel encapsulated phase change materials (PCM) for use in thermal storage applications to significantly reduce the LCOE for baseload CSP plants.


Terrafore is determining a cost-effective way to produce small 10 mm to 15 mm capsules containing phase change material (PCM salt) in a suitable shell material. Large numbers of these PCM capsules provide high-heat transfer surface and store heat as sensible and latent heat of fusion of salt. The capsules with different PCMs inside the shell are stacked inside a single tank to provide a cascaded storage to effectively use the latent heat of fusion of salts over the solar collection temperature range.


In addition to taking a new approach to PCM encapsulation methods, Terrafore is also:

  • Designing a single, packed-bed tank system to add and extract heat from the salt in the encapsulated beads by direct contact between a suitable heat transfer fluid (HTF) and the beads
  • Designing a controller to actively maintain thermal stratification by using predictive control strategies.

The technical objective of this project is to determine how to prevent the rupturing of the encapsulating shell, or capsule, when the core PCM melts and the volume increases.

Publications, Patents, and Awards

At this time, this project does not have published articles, patents, or awards.

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Quarterly Progress Reports

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