Thermal Performance Testing of Outdoor Hot Water Stores for Long-Term Thermal Energy Storage
Abstract
This contribution describes a model-based thermal performance test method for outdoor hot water stores for long-term thermal energy storage. For this purpose an existing TRNSYS model for indoor hot water stores is modified. In particular, local variations of the ambient temperature and the influence of solar irradiation are taken into account. A parameter identification process is proposed, which makes it possible to determine the parameters of the model required for the characterization of the thermal performance of an outdoor installed hot water store. The test method has been developed for an outdoor installed hot water store with a volume of 12 m3, a vacuum thermal insulation and a transparent thermal insulation as well as for an outdoor installed 100 m3 hot water store with a conventional thermal insulation. The functionality of the test method is confirmed by measured data, plausibility checks of the model parameters and a comparison to theoretical values determined based on material properties. Furthermore, the influences of the minimization algorithm on the results of the parameter identification process are investigated.