In sorption heat storage, one of the sources of discrepancy between theoretical material based energy storage potential and resulting system performance is the choice of process type. In this paper, in order to understand this performance deviation, a sorption heat storage process categorisation is proposed. This is followed by a review of reported sorption systems categorised according to the proposed process classification. An analysis of the reported systems is then undertaken, focusing on the ratio of resulting temperature gain in sorption (ad- or absorption), compared to required temperature lift in desorption. This measure is termed temperature effectiveness and enables a form of system performance evaluation in the broad landscape of sorption thermal energy storage demonstrators. It is argued that other performance parameters such as volumetric energy storage density and volumetric charge and discharge power density are not adequate for comparison due to the highly varying testing conditions applied. From the system evaluation, it is seen that best temperature effectiveness is generally found in a closed, transported process with the ability of single sorbent pass and true counter flow heat exchange.

The aim of this project is to find materials and possibilities that allow thermal storage at temperatures in the range of 8 to 15 ° C (PCM8-15) and 50 ° C (PCM50) in addition to today's ice storage. Ice storage for storing latent heat for cooling purposes are now operated with water. For new applications in the field of air conditioning and heating, a higher temperature level is exergetically much cheaper. Based on the PCM with the phase transition temperature of 50 ° C, the storage density can be achieved in the useful hot water storage. This reduces the storage space of the thermal energy store. The material chosen has phase change occurring at 10°C.