Optimal Experimental Design for the Analysis of a Novel Hybrid Steam Storage

With the ongoing transition from fossil to renewable energy sources and the progressing decarbonisation of the economy, the development of energy storages gains in importance. Thermal energy storage (TES) systems can increase the energy efficiency of industry processes through the possibility to store heat that would otherwise be released into the environment as waste heat. A common TES used in the industry is the Ruths steam storage(RSS). In the HyStEPs project, in which this thesis is embedded in, a novel approach of increasing the storage capacity of a RSS by surrounding it with a latent heat energy storage, which uses the phase change of a material to store large energy quantities, is researched. As a preparation for the experimental investigation on this hybrid storage system, a detailed design of experiment was established in the course of this thesis. Through the implementation of an optimal experimental design (OED), the experimental conditions get optimized in order to increase the sensitivity of the experiments with regard to selected parameters. In this thesis, an OED for two sub-models of the hybrid storage was performed using statistical criteria which rely on scalar functions of the Fisher information matrix. It was proven, that the optimized storage loading scenarios led to higher parameter sensitivities than if charged and discharged with a trivial load case. Based on the conducted OED, a fully developed experimental plan for the upcoming experiments on the HyStEPs prototype storage was established. In addition to the experimental design, an upscaling model for the hybrid storage was developed, which allows to presume the necessary dimensions and expected costs of the storage depending on the desired maximum storage capacity.