Life Cycle Assessment of Thermal Energy Storage Materials and Components

The main objectives of research on innovative materials (phase change materials, PCM, or thermochemical materials, TCM) for thermal storage are the development of low-loss and compact storage systems with high capacity (sensible water storages being the benchmark). If the storage is to be implemented in an application with the aim to increase its energy efficiency, beside the technical/thermal properties and cost factors, also the environmental impact of the storage production and operation need to be considered during development. Yet up to now, a holistic development approach that considers the primary energy used for the manufacturing, operation and disposal in relationship to the potential energy savings does not exist for innovative storage concepts. Therefore, we are presenting data on the environmental impact of PCM and TCM on material and component level developed within the German project ""Speicher LCA"" (engl. ""Storage Life Cycle Assessment""). The evaluation shows that PCM can be environmentally beneficial compared to water, if they are used in an application with a small useful temperature difference (e.g. cooling). Storing solar thermal heat with solid sorption materials in a closed system does not seem environmentally beneficial. Additional scenarios assuming the possible reuse of undegraded material, configurations with open sorption storage and/or other material classes (such as salt hydrates and liquid sorption) will be studied in the future.