Digitalization and concepts such as digital twins (DT) are expected to have huge potential to improve efficiency in industry, in particular, in the energy sector. Although the number and maturity of DT concepts is increasing, there is still no standardized framework available for the implementation of DTs for industrial energy systems (IES). On the one hand, most proposals focus on the conceptual side of components and leave most implementation details unaddressed. Specific implementations, on the other hand, rarely follow recognized reference architectures and standards. Furthermore, most related work on DTs is done in manufacturing, which differs from DTs in energy systems in various aspects, regarding, for example, multiple time-scales, strong nonlinearities and uncertainties. In the present work, we identify the most important requirements for DTs of IES. We propose a DT platform based on the five-dimensional DT modeling concept with a low level of abstraction that is tailored to the identified requirements. We address current technical implementation barriers and provide practical solutions for them. Our work should pave the way to standardized DT platforms and the efficient encapsulation of DT service engineering by domain experts. Thus, DTs could be easy to implement in various IES-related use cases, host any desired models and services, and help get the most out of the individual applications. This ultimately helps bridge the interdisciplinary gap between the latest research on DTs in the domain of computer science and industrial automation and the actual implementation and value creation in the traditional energy sector.

This work examines a high temperature latent heat storage system, which could find use in future concentrated solar power and other combined heat and power plants. In contrast to lab-based fully charged or totally discharged states, partial load states will be the principal operation states in real-world applications. Hence, a closer look on the partial load states and the effective power rates are worthwhile for a successful implementation of this storage type. A vertical finned shell and tube heat exchanger pipe with a combination of transversal and longitudinal fins is applied. Sodium nitrate with a melting temperature of 306 °C is used as phase change material and thermal oil serves as heat transfer fluid. Temperatures in the storage and the heat transfer fluid as well as the mass flow are measured for data analysis. The state of charge formulation is based on an enthalpy distribution function, where the latent heat of fusion is spread over a specific temperature range.