STUDY ON THE STANDBY CHARACTERISTICS OF A PACKED BED THERMAL ENERGY STORAGE: EXPERIMENTAL RESULTS AND MODEL BASED PARAMETER OPTIMIZATION

In the present study the standby characteristics of a packed bed thermal energy storage are investigated experimentally and numerically. The results collected from the experiments are used for the development of a thermal model of the storage that will act as the virtual entity in a digital twin platform. A packed bed thermal energy storage is a sensible type of thermal energy storage that is capable of storing excess heat for several hours and even days. In this study experimental data from a lab-scale test rig is used to make statements on the thermal characteristics of the storage during standby periods. In addition, the experimental data and a finite volume model of the test rig are used for model-based parameter optimization. The developed model is able to predict the thermal behaviour of the storage in standby and can be utilized as the virtual entity in a digital twin platform. The evaluation of the measured data is done with first and second law analysis and nonlinear optimization. The results are contributing to the further development and deployment of packed bed thermal energy storage systems for waste heat recovery in industrial processes and to increasing flexibility of renewable power generating technologies.