Assessment of Residential Scale Renewable Heating Solutions with Thermal Energy Storages

Thermal energy storage technologies significantly increase the benefits of decentralized renewable energy production on residential scale. While many studies investigate singular applications of thermal energy storages or provide a broad overview about the current state of research in this field, there is no comprehensive assessment on market-ready solutions. This paper combines a system performance analysis for the combination of photovoltaic and solar thermal generation with storages based on building energy system simulations. Energy systems for single- and multi-family reference buildings with low energy consumption, representing the most common retrofit case in Switzerland, are designed on equal energy performance, and later evaluated for total costs of ownership and financial payback. The results highlight the operational difference in thermal energy storages, where some technologies act more like an energy source in their optimal sizing. Variation of renewable input versus storage size emphasize the individual optimal storage duration. Many solutions are capable of substantially increasing the degree of energy autarky while being competitive without subsidies. This assessment helps guiding future development and design of thermal energy storages.