Measuring the Maximum Capacity and Thermal Resistances in Phase-Change Thermal Storage Devices

Allison Mahvi, Kedar Prashant Shete, Adewale Odukomaiya, Jason Woods

Research output: Contribution to journalArticlepeer-review

4 Scopus Citations


Thermal energy storage can increase the efficiency of the electric grid by adding flexibility to thermal systems. The value of thermal storage is a function of its energy and power density, which are driven by the capacity and thermal resistances in the storage device. Measuring these properties in-situ at the device level is an important step to understanding the performance and improving the design of thermal storage systems. In this paper, we present methods to measure the total capacity and thermal resistances in heat exchangers with integrated phase change materials. These methods are demonstrated on two thermal storage devices—a 570-kWh ice-based storage tank and a 0.35-kWh graphite-tetradecane composite device. The results show how thermal resistances evolve with the state of charge and discharge rate in these devices and quantify the impact of applied pressure on the contact resistance in composite phase change material heat exchangers. The proposed method allows for easy comparison between different systems and provides information on the thermal bottlenecks limiting performance. Ultimately, these measurements will allow designers to make robust, high-performance thermal storage devices for next-generation thermal systems.

Original languageAmerican English
Article number105514
Number of pages10
JournalJournal of Energy Storage
Issue numberPart B
StatePublished - 2022

Bibliographical note

Publisher Copyright:
© 2022 Elsevier Ltd

NREL Publication Number

  • NREL/JA-5500-80823


  • Capacity
  • Metrology
  • Thermal energy storage
  • Thermal resistances


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