Thermal Energy Storage Technology for Industrial Process Heat Applications

This paper deals with the assessment of different thermal energy storage technologies for solar process heat application. Three different storage concepts are discussed in detail: sensible solid media storage, steam accumulators, and phase change energy storage. The first two systems are sensible storage systems and the latter one is using solid-liquid phase change of salts for isothermal heat storage. All three concepts are superior to commercially available pressurized water storage units. For the assessment of the different concepts a reference case was defined consisting of a solar system providing saturated steam for an industrial process demanding heat at 140 °C. The temperature difference between operation temperature of the solar system and the industrial process has significant influence on the assessment of the different storage technologies. A small temperature difference of 20K or even less shows significant advantage of the PCM storage approach. Values in the order of 60K lead to an adjustment of the cost of the different concepts. In this case a more detailed evaluation is required to identify the most economic technology.