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

SunShot Initiative

Novel Thermal Storage Technologies for Concentrating Solar Power Generation

Lehigh logo

This cross section shows Lehigh's stainless steel capsule containing phase change materials.

Lehigh University, under the Thermal Storage FOA, is working to establish the technical feasibility of using phase change materials (PCM) at elevated temperatures and to acquire engineering results that will lead to the demonstration of large-scale thermal storage systems.


Along with bench-scale testing using specially made encapsulated phase change material (EPCM), this project is pioneering storage methods that would be applicable for large-scale implementation of thermal energy storage. The team aims to:

  • Develop two methodologies with different designs and materials. Zn or MgCl2-NaCl eutectic salt mixtures are to be used as phase change materials for the energy storage.
  • Develop technologies that will enable storage of thermal energy in 100-MWe solar energy plants for 24 hours or more at temperatures around 420°C. The storage methods will be readily useful for the overnight and cloudy time use, with 24-hour power generation at higher efficiencies in large solar plants that use steam-based Rankine cycles.
  • Explore cheap PCM materials along with inexpensive encapsulation materials to try and reach thermal energy storage costs of $15 per kilowatt-hour thermal.



Lehigh is focusing on developing EPCM in either particulate (near spherical) or tubular forms, both of which would be assembled into heat exchangers for thermal exchange with heat transfer fluids. This work builds upon the team's unique experience for encapsulation of PCM using an electrochemical coating technique. Two PCMs under consideration are Zn and eutectic mixtures of MgCl2-NaCl, with the primary focus on Zn. Nickel is envisioned for the encapsulation material for Zn and or stainless steel for the salts. Scoping analysis has shown that nominal dimensions of 1–5 cm would be suitable for the EPCM, giving the promise for ease of fabrication and assembly into heat exchangers. Lehigh plans to have developed sufficient engineering detailed designs tails to hand over the technologies for demonstration-size plants.

Publications, Patents, and Awards

SunShot logo

Quarterly Progress Reports

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