EVALUATION OF THE SODIUM SELENITE AND TELLURRATE TO THE THERMODYNAMICS OF HEAT ACCUMULATION BY COMPOSITES BASED ON SODIUM THIOSULPHATE

The main category of materials wear in the process of transport, residential premises operation is a temperature difference between external and internal, a high gradient and cyclic changes in the temperature regime lead to changes in the materials structure and an increase in energy consumption. Therefore, an urgent problem along with the development of heat-storage materials which make it possible to reduce significantly the heat loss to the environment is the matrix modification through the introduction of various additives. The aim of this investigation is the establishing of adding sodium tellurate and sodium selenate to sodium thiosulfate pentahydrate influence on the heat-storage properties of the obtained mixtures. The behavior of sodium selenate and sodium tellurate in the composition of the mixture with sodium thiosulfate crystalline hydrate was studied by the conductivity method. The changes in the activity coefficients of sodium selenate, the contribution of sodium selenate to the heat content of the mixture with sodium thiosulfate pentahydrate were calculated. Also, the changes in the activity coefficients and association degrees of sodium tellurate - sodium thiosulphate pentahydrate mixtures (1:50) were calculated, according to which the complex formation process is exothermic, heat storage process is electrostatic in nature. Consequently, the stability of the associates is decreased with increasing temperature. It was also found that the mixture cooling to T=298 K releases into the environment up to 100 kJ/kg of heat. The temperature of transition to the active state is 353 K. As a result of the studies, optimal warming temperature T=348 K, stabilizing effect of tellurate ion on sodium thiosulfate with water molecules associates were found, which together allows the energy coming to the system accumulation, its release during cooling with subsequent.