Thermochemical Seasonal Solar Heat Storage in Salt Hydrates for Residential Applications – Influence of the Water Vapor Pressure on the Desorption Kinetics of MgSO4.7H2O

AbstractAn interesting thermochemical material for compact seasonal heat storage is magnesium sulfate heptahydrate MgSO4·7H2O. Previous studies in the field showed that this material presents a storage energy density of 1 GJ/m3 when the material is built in a TC storage system with a 50% porosity packed bed reactor. However, the material has slow reaction kinetics under the low vapor pressure typically occurring in a seasonal heat storage (13 mbar). The kinetic study presented in this paper shows that a higher water vapor pressure of 50 mbar increases the reaction kinetics of the dehydration process of MgSO4•7H2O, improving the performance of the material