Thermal Storage: From Low‐to‐High‐Temperature Systems

• Published in: Energy technology (Weinheim, Germany) Germany), 2023-12, Vol.11 (12), p.n/a
• Main Authors: Gamisch, Sebastian, Kick, Moritz, Klünder, Franziska, Weiss, Julius, Laurenz, Eric, Haussmann, Thomas
• Format: Article
• Language: English
• Subjects: Adipic acid; Aging (materials); Cold storage; compatibility testing; Degradation; degradation, phase change materials; Enthalpy; fillers; Heat; Heat exchangers; High temperature; immersed heat exchangers; macroencapsulation; molecular dynamic simulations; Molecular dynamics; Nucleation; phase change emulsions; Phase change materials; Supercooling; Temperature; Thermal cycling; Thermal energy; Thermal power; Thermal storage
• ISSN: 2194-4288; 2194-4296
• DOI: 10.1002/ente.202300544

Different technologies of cold and heat storages are developed at Fraunhofer ISE. Herein, an overview of ongoing research for sensible and latent thermal energy storages is provided. Phase change emulsions are developed supported by molecular dynamic simulations. A narrow temperature range of the phase change is crucial for the applicability. By the simulations, a nucleation additive is identified that reduces supercooling by up to 9 K. The long‐term stability of phase change material is investigated by degradation experiments. Thermal cycling and ageing of materials at elevated temperature are applied. The change of melting enthalpy and characteristic temperatures are evaluated. Among erythritol, adipic acid, and myristic acid, the smallest degradation is observed for the latter. For sensible storage, the reduction of thermal oil by low‐cost filler materials and their compatibility is investigated at elevated temperature. It can be concluded that the materials are compatible up to 320 °C. At the component level, different macroencapsulations and immersed heat exchangers are tested for phase change materials. The investigated configurations achieve similar values of thermal power during (dis‐)charge. Compared to water as storage medium, the capacity increases by a factor of 2.2 and 4.1 for the macroencapsulation and the immersed heat exchanger, respectively. Ongoing research for sensible and latent thermal energy storages at Fraunhofer ISE is presented. Results from the activity at material and component level including development of phase change emulsions with molecular dynamic simulations, investigation of degradation of phase change materials, compatibility testing of filler materials and heat exchanger system testing are presented.