Increasing the sustainability of buildings by using thermal energy storage

The final energy consumption of the built environment depends on the mismatch between its instantaneous energy demand and the energy supplied by on-site sources: buildings need to be cooled when there is abundant environmental heat and heated when the surrounding environment is cold. Thermal energy storage (TES) can help to reduce the global warming potential of buildings by storing environmental, renewable or waste heat for later use when heating is needed. In this Review, we assess the economic, environmental and social aspects of TES technologies. TES tanks require high charging and discharging power, calling for the development of new heat exchangers and storage media, such as phase-change materials. Integrating TES into local energy communities could reduce energy costs and lower the emissions caused by space and water heating, but challenges remain: price volatility and the deployment of longer-term thermochemical TES for seasonal storage, for example. The efficiency of TES operation could be increased by using advanced control systems, including artificial intelligence techniques. With the development of increasingly complex systems for TES, we highlight the importance of circular design thinking and end-user engagement in optimizing the development and deployment of future TES systems.