Thermal energy storage technologies are an important part of our research. Here, we store surplus heat or cold to be used when needed. In other words, the supply of heat or cold is decoupled from demand. This solves the daily imbalance between heat demand at household level and the supply of heat from renewable sources (such as solar collectors or PV-coupled heat pumps). Various techniques are possible to store heat or cold, from water tanks to the more exotic-sounding PCM (Phase Change Material) and thermochemical storage. Furthermore, storage can also add operational flexibility and helps increase energy system efficiency.
Thermal energy storage systems are also used in industrial processes and buildings. In these applications, about half of the energy is used in the form of thermal energy. Thermal energy storage systems can help balance energy demand and supply and do so in different time frames. For example, a domestic hot water buffer stores heat for a few hours or days, while underground borehole energy storage can store heat for an entire season.
Furthermore, thermal storage can play an important role in connecting thermal and electric grids. Connecting thermal energy storage to an electric grid requires conversion systems such as heat pumps or ORCs. For thermal grids, storage can play a balancing role between energy production, conversion systems and users, both in the short (day-night) and long term (winter-summer). Within EnergyVille, we conduct research on the development, demonstration and implementation of compact energy storage based on PCM and storage of industrial medium- and high-temperature heat via optimal configurations of packed-bed technology.