The proportion of volatile energies in energy generation is constantly increasing. Energy storage is becoming increasingly important in order to synchronise generation and demand. To date, highly simplified models have been used to analyse complex district heating systems that include a water heat storage system. In order to further develop and validate such models, measurements must also be carried out on real storage tanks as examples. For this purpose, a large short-term water heat storage tank at Entega AG was equipped with appropriate temperature measurement technology. Parallel to analysing the measurement results, high-resolution models were developed and numerical simulations carried out. Simplified models for large short-term water heat storage tanks were then derived on this basis.

The results show that a larger aspect ratio leads to increased heat loss to the environment and lower exergetic performance. However, the capacity for more stable and efficient thermal stratification is also increased.