Analysis of a Lab-Scale Heat Transformation Demonstrator Based on a Gas-Solid Reaction

Abstract

Heat transformation based on reversible chemical reactions has gained significant interest due to the high achievable output temperatures. This specific type of chemical heat pump uses a reversible gas-solid reaction, with the back and forward reactions taking place at different temperatures: by running the exothermic discharge reaction at a higher temperature than the endothermic charge reaction, the released heat is thermally upgraded. In this work, we report on the experimental investigation of the hydration reaction of strontium bromide (SrBr2) with regard to its use for heat transformation in the temperature range from 180 °C to 250 °C on a 1 kg scale. The reaction temperature is set by adjusting the pressure of the gaseous reactant. In previous experimental studies, we found the macroscopic and microscopic properties of the solid bulk phase to be subject to considerable changes due to the chemical reaction. In order to better understand how this affects the thermal discharge performance of a thermochemical reactor, we combine our experimental work with a modelling approach. From the results of the presented studies, we derive design rules and operating parameters for a thermochemical storage module based on SrBr2.