Dronninglund water pit thermal energy storage dataset

Water pit heat storage has been proven a cheap and efficient storage solution for solar district heating systems. The 60,000 m3 pit storage in Dronninglund represents in many ways the state-of-the-art large-scale heat storage, demonstrating a storage efficiency higher than 90% during its operation. The storage is used for seasonal and short-term heat storage of solar heat generated by a 37,573 m2 solar collector field and supplies heat directly to the district heating grid or is used during winter as an alternative heat source to a heat pump. This study aims to provide an overview of the available information on the Dronninglund water pit heat storage, including a detailed description of the design, ground conditions, and operating strategy. The used dataset (2014–2020) has been the foundation for most investigations and simulations of pit thermal energy storages. However, due to a lack of public documentation, various studies have used different post-processing methods and assumptions, leading to inconsistent results. Therefore, the dataset has been manually quality-controlled, and erroneous data have been removed with the aim of establishing a high-quality reference dataset. Moreover, an overview of the available parameters and metadata is provided, along with example plots. To promote the usage of the quality-controlled dataset, all the developed quality-control routines and Python scripts are made available on GitHub.