Experimental evaluation of a heat transport system for a high-temperature storage unit

Abstract

The thermal storage system, developed by DLR, utilises the sensitive change in temperature and the phase change of the storage material to store energy. During charging, the metallic Phase Change Material (mPCM) is heating and melting, while during discharging, it is cooling and solidifying. Intelligent need-based charging can be carried out in parallel when charging the traction battery at the charging station. The heat released during the subsequent discharging can be made available to the interior of the car. A possible approach to make the stored thermal energy accessible is to thermally link the storage unit with the cooling cycle of the car. Due to high temperatures, which would evaporate the coolant, a flow through the storage unit is not possible. Instead, a concept for indirect coupling was developed to transport a certain amount of heat within a closed circuit between both systems. Within this concept, evaporation and condensation of a working fluid are the dominating transport phenomena. Numerical investigations were undertaken within the simulation software Dymola to estimate the performance of the developed concept. As a further step, the validation of the numerical analysis was targeted by an experimental investigation. Therefore, a test bench was built and experimental series were undertaken.