Characterization of potassium carbonate salt hydrate for thermochemical energy storage in buildings

Thermochemical heat storage in salt hydrates is a promising method to improve the solar fraction in the built environment. One of the most promising salt hydrates to be used as thermochemical material is potassium carbonate. In this study, the use of potassium carbonate in heat storage applications is investigated experimentally. The most important objective is to form a kinetic model for the de/re-hydration reaction of the material. In order to do so, it is crucial to understand the behavior of the salt when it reacts with water vapor. Reaction kinetics and mechanism are investigated for K2CO3, as one of the most promising materials. Characterization of the materials is carried out with combined Thermo-Gravimetric Analysis (TGA) and Differential Scanning Calorimetry (DSC) methods. By employing the experimental results, kinetics models are developed for the hydration and dehydration reactions of the material. The kinetics model can be further used to predict the performance of a heat storage system working with K2CO3. In addition, cyclability and reaction enthalpy are investigated.