Seasonal Thermal Energy Stores - Design, Operation and Applications

The seasonal storage of solar heat or waste heat from combined heat and power generation can significantly help to replace large amounts of fossil fuel in future energy systems. Central solar heating plants in combination with seasonal thermal energy storage can reach solar fraction of 50% or more of total heat demand. The construction and operation of several pilot projects for central solar heating plants with seasonal thermal energy storage confirmed that a high solar fraction is possible in Germany. Four different types of seasonal thermal energy storage have been developed, tested and long-term monitored under real operating conditions: hot water-, gravel/water-, borehole- and aquifer thermal energy storage.