Assessment of thermally activated inner building components or a high temperature stone storage system to utilize surplus renewable electrical energy

In electrical grids with high renewable percentage, the production is less demand-driven, but more dependent on weather conditions. Usually there are periodical weather patterns in the winter period with substantial amounts of wind energy production. Sometimes this results in a shut-off of the wind turbines due to the inability of the grid to use the produced power (overproduction). This paper assesses two thermal storage systems to service space heating and domestic hot water that exploit the overproduction of electricity and thereby bridge periods of lower electricity production. The first system utilizes inner walls and ceilings with a thermally activated building system (TABS) to store and dissipate heat. The second system is a stand-alone high temperature stone storage system (HTSS). Models to simulate such systems within a whole building simulation framework are introduced and the verification with measured data from field measurements is presented. Both models are used to assess the systems with regard to the speed of loading and the potential to bridge time periods without additional heating in high-performance buildings. It is shown that both systems can provide heating and domestic hot water (DHW) up to 13 days without substantial additional electricity.