Large Scale Heat Storages for Solar District Heating

Denmark is the international frontrunner on large scale application of renewable energy systems. In the last four years, more and more Danish district plants have been equipped with large heat storages in the form of water pits with the aim to increase flexibility and stability of the energy system. The large scale heat storages are designed and operated based on limited experiences from the past and on learning by doing. Research is needed in order to optimally integrate and operate the heat storages in district heating systems with a large share of renewables. The proposed PhD project aim to include the following technical challenges:

• Analysis of existing solar heating plants with seasonal heat storages, both in Denmark and in China
• Development of simulation models for large scale heat storages with focuses on underground water, thermal stratification, soil properties
• Round robin tests of the simulation models of the LTES
• System integration of the LTES with solar heat, heat pump, waste heat and other sustainable energies
• Design optimization of heat storages for integration in a hybrid renewable energy system with focuses on system flexibility, reliability and profitability under Danish and Chinese conditions
• Investigation of advanced control strategies, for example, load forecasting, production forecasting
• Digital twin and data-driven methods for solar heating plants with LTES