Thermal Storage by Thermoreversible Chemical Reaction Systems

Recent research work on the development of smart pumpable materials for thermal storage at temperatures below 200 °C will be presented. Currently two different systems being analyzed: additive enhanced CO2-hydrates for climate and cooling purposes and neutralization reactions of organic acids with nitrogen bases for waste heat utilization. CO2-hydrate formation and growth are studied while using hydrogel additives of different morphological structure. In particular hydrogels with a low content of cross- linker significantly promotes the hydrate formation. Several combinations of organic acids and bases are tested in mixing experiments and show that high energy densities can be obtained by these neutralization reactions in liquid systems. Special emphasis is put on the option of long-term-storage of heat. This possibility is demonstrated by distilling off the acid component for the reference reaction system trioctylamine and acetic acid.