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

SunShot Initiative

Innovative Application of Maintenance-Free Phase-Change Thermal Energy Storage for Dish Systems

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Infinia is developing a thermal energy storage (TES) system that uses Phase Change Material (PCM) as the thermal storage media and employs the high temperature heat pipes to transfer heat from receiver to PCM and PCM to Stirling engine.

Infinia, under the Thermal Storage FOA, is developing a thermal energy storage (TES) system that, when combined with Infinia's dish-Stirling system, can achieve DOE's CSP cost goals of $0.07/kWh by 2015 for intermediate power and 5¢/kWh by 2020 for baseload power.


Infinia's storage system is designed to be capable of >93% round-trip efficiency. This adds incremental value to the system for identified users, thus reducing overall system cost. The project phase objectives are:

  • Phase I: Provide proof-of-concept
  • Phase II: Build and demonstrate TES/CSP prototype
  • Phase III: Deliver and test a statistically significant number of TES/CSP systems (40 to 50)


Dish Stirling systems have long been considered to have excellent prospects for providing low-cost, large-scale, high efficiency solar power. However, up to this point, dish systems have lacked the storage capability that would allow them to dispatch power during cloud-transients and at night. Infinia is addressing this issue by modifying its 3-kW dish-Stirling design to provide 4–6 hours of storage. This novel approach uses a thermal salt phase-change material (PCM) between the solar thermal receiver and the engine for isothermal operation, which is required for dish-Stirling systems.

By providing a viable storage option, Infinia is giving dish/engine technology an advantage over photovoltaics, which currently competes in the same small- to large-scale market for solar power.

Publications, Patents, and Awards

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

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Quarterly Progress Reports

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