Thermal conductivity measurement of thermochemical storage materials

International audienceThermal properties related to heat and mass transfer are crucial when designing thermochemical heat storage systems. Therefore, enhancing this phenomenon lies in the thermal conductivity of the used material. The effective thermal conductivity of salt hydrates and host matrices is measured using two different methods by differential scanning calorimeter from 100 to 200 °C and radial flow apparatus called guarded hot cartridge from 20 to 70 °C, where the method effect is less than 12%. On this latter, the results as function of temperature was modelled and theoretical correlation of effective thermal conductivity of the material bed presented. Four inorganic salts often used in thermochemical energy storage (CaCl2, MgCl2, SrBr2 and MgSO4) and host matrices (activated carbon, expanded natural graphite and silica gel) were used as samples and the results on both systems for only salts give a thermal conductivity in the range of 0.3–1.3 W m−1 K−1 with measurement uncertainty less than 14%. These obtained data are satisfactory with literature values. Regarding the results, the need of composite design is mandatory to achieve great thermal performances in thermal storage systems, especially in closed systems. The presented results can be used for the evaluation and the improvement of heat and mass transfer in thermochemical and sorption heat storage systems