Device for determining the charge status of a thermal storage device

摘要

The device (24) comprises an adjustment unit that adjusts a defined phase boundary between solid and liquid phases of an introduced phase change material in a hermetic sealed space (14) of a thermal storage (12). The pressure in an inert gas reservoir arranged over the liquid phase of the phase change material is changed due to change in volume occurred with phase change of the phase change material. A measuring unit is provided to detect the state of charge of the thermal storage. The phase change material is selected from a mixture of the water and salts or alcohols.