The EU project EINSTEIN aims to reduce the (primary) energy consumption in buildings by a combination of Seasonal Thermal Energy Storage (STES) to store solar thermal energy and high efficiency heat pumps.
Energy use in buildings accounts for approximately 40% of EU energy consumption. The potential to save energy is largest in the existing building stock. New developments and adaptation of existing technologies are needed for a drastic reduction of energy use.
A promising methodology consists of large scale seasonal energy storage systems, such as aquifers and tanks or pits. The stores are filled in summertime with heat harvested by solar collectors. In wintertime, the stored heat is used and upgraded to a higher temperature level if needed, using a high efficiency heat pump. The heat is used for space heating and domestic hot water.