In the winter months demand for heating in buildings rises sharply in Europe. An EU-funded project is exploring three different technologies that could store heat energy made when the sun is warm in the summer, for use during colder seasons.
Solar thermal technology can be used to supply renewable heat in buildings covering 15% - 40% of the building’s heat and hot water demand. This share could rise if storage technologies were used to store up excess energy from the summer months for when the demand is greater in the winter.
The Austrian-led project - COMTES - is working on new systems for storing solar thermal energy. It is developing three different types of compact thermal storage technologies based on solid sorption, liquid sorption and using super cooling Phase Change Material at various sites across Europe. These systems are thought to be better than water-based storage technologies since they take up much less space and result in far fewer heat losses over time.
The solid sorption system has been built at the AEE-Institute for Sustainable Technologies (AEE Intec) site in Gleisdorf, Austria. It involves the absorption of water vapour in a material called zeolite. The liquid sorption system is being explored at the EMPA Institute in Switzerland using sodium hydroxide as its absorption material. Finally, the super cooling system – based at the DTU Technical University of Denmark - uses sodium acetate trihydrate as its heat absorption material.
Thermal storage technologies can help the EU achieve its renewable energy and energy efficiency targets by enabling a higher portion of renewables to come online as well as improving efficiency by balancing the availability of energy and the demand.
The total cost of the COMTES project is €6 647 969.6 including €4 735 020.6 in EU funding.