Experimental Demonstration of a Dispatchable Latent Heat Storage System with Aluminum-Silicon as a Phase Change Material

Jonathan E. Rea, Christopher J. Oshman, Abhishek Singh, Jeff Alleman, Philip A. Parilla, Corey L. Hardin, Michele L. Olsen, Nathan P. Siegel, David S. Ginley, Eric S. Toberer

Research output: Contribution to journalArticlepeer-review

33 Scopus Citations


In this work, we present the design, construction, and experimental results of a prototype latent heat thermal energy storage system. The prototype consists of a thermal storage tank with 100 kg of the aluminum-silicon eutectic as a phase change material, a valved thermosyphon that controls heat flow from the thermal storage tank to the power block, and thermoelectric generators for conversion of heat to electricity. We tested the prototype over four simulated days, where each day consisted of four phases of operation: charging, discharging, simultaneous charging and discharging, and storage. Our results show three major conclusions. First, the thermal energy storage system was able to receive and distribute heat with small temperature gradients – less than 5 °C throughout the thermal storage tank. Second, the valved thermosyphon was able to effectively control heat transfer, demonstrating an on/off thermal conductance ratio of 430. Third, the interfaces between subsystems had small temperature drops: of the ∼ 560 °C temperature drop from the thermal storage tank to the heat rejection system, ∼ 525 °C occurred across the power block. This work overcomes the challenges of integrating previously-developed subsystems together, providing a proof-of-concept of this system.

Original languageAmerican English
Pages (from-to)1218-1229
Number of pages12
JournalApplied Energy
StatePublished - 2018

Bibliographical note

Publisher Copyright:
© 2018

NREL Publication Number

  • NREL/JA-5400-72533


  • Concentrating solar power
  • Heat pipe
  • Phase change material
  • Thermal energy storage
  • Thermal valve
  • Thermosyphon


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