Lehigh Researchers Build Concrete Thermal Battery to Reuse Data Center Heat

The system stores recovered heat before releasing it for cooling, industrial processes, electricity generation and other applications requiring thermal energy. TechRadar reported that after a complete charging and discharging cycle, the measured efficiency exceeds 70%, meaning a substantial share of supplied energy remains recoverable after storage.

The technology combines an engineered cement material with embedded thermosiphons that transfer heat through the storage medium during charging and discharge. These components move thermal energy rapidly while maintaining relatively stable temperatures, so stored heat can become available when demand changes. The system can accept waste heat from servers as well as electricity, giving it two routes for charging. Researchers describe the arrangement as hybrid because it combines different heat storage mechanisms inside a concrete-based structure. The design also allows thermal storage to operate separately from the moment waste heat is produced, providing timing flexibility for facilities whose computing loads and cooling needs fluctuate.

For data centers, the technology can upgrade recovered heat into a range between 120°C and 220°C for useful thermal applications, according to TechRadar. That range could supply absorption chillers for cooling, while stored heat could also support drying, district heating and industrial operations. The approach gives operators another way to use heat that conventional cooling equipment normally removes before releasing it directly outside. It can connect computing facilities with nearby thermal demands, potentially allowing recovered energy to serve purposes beyond immediate cooling.

Stored heat can also drive low-temperature Rankine cycle equipment, with possible installations ranging from kilowatt systems to facilities operating at megawatt scale. Absorption cooling offers another application, allowing stored thermal energy to produce chilled conditions without relying entirely on electrically driven refrigeration equipment. The team describes temperature upgrading as an important function when recovered data center heat needs to reach higher usable temperatures. The system can also operate with electricity-driven heating, allowing operators to charge storage when electrical supply conditions make that approach practical.

TechRadar reported that the technology was partly funded by Federal energy and has now been licensed to a private energy company, allowing further development toward integration with existing energy infrastructure. The project could eventually connect thermal storage with existing energy networks while recovering useful heat from industrial operations and nearby facilities.