Operation Optimization of Steam Accumulators as Thermal Energy Storage and Buffer Units

Modeling of a Hybrid Steam Storage and Validation with an Industrial Ruths Steam Storage Line

Phase change materials are used in latent heat thermal energy storages to store a high amount of energy during phase change. A hybrid storage concept was developed with the aim of utilizing this high storage capacity in combination with Ruths steam storages. In the concept, a container filled with phase change material is placed at the shell surface of the Ruths steam storage. This container can be divided into several chambers filled with different phase change materials. An arrangement of electrical heating elements or heat exchangers at the internal side of these chambers is also provided. In this paper, a model of the hybrid storage concept is developed. The model consists of different sub-models, which are connected to each other. The simulation results of a hybrid storage show how important the model is for the analysis of the concept. Furthermore, the validation of the Ruths steam storage sub-model with operational measurement data of a storage line is presented. A maximum deviation between the operational measurement data and the simulation results of 6.43% occurs in terms of pressure at the internal side of the pressure vessel. In addition, the latent heat thermal energy storage sub-model was checked with the analytic solution.