Kolomiyets O. The increase of adsorption efficiency of heat energy transformers at the expense of new composite sorbents "silica gel hydrated"

The thesis deals with the study of adsorption heat transformers with the use of ‘silica gel hydrated’ composite sorbents, which were obtained by zol-gel method. These sorbents are characterized by heightened sorption capacity and heat content density. The technological principles of new class of sorption composite materials ‘silica gel-Na2SO4‘ and ‘silica gel-СН3СООNa’ were developed. It was shown that the obtained composite sorbents are characterized by the high water sorption – about 0,5 – 0,65 g/g and their heat accumulation ability is 0,30 - 0,36 kWh/kg. The regeneration temperature for composite ‘silica gel-Na2SO4‘ amounted to 60°C, and for ‘silica gel-СН3СООNa’ – to 55°C. It was determined, that the properties of obtained composite sorbents ‘silica gel - hydrate’ are not a linear combination of silica gel and massive salt properties. At hydration process the kinetic regime typical to massive salt transforms into the diffuse regime, when the limit stage is the water transport to the salt through the porous silicon-oxygen matrix. The technology of industrial production of composite sorbents on the base of sodium sulfate and sodium acetate was developed. It consists of three stages: 1) preparation of aqueous solution of silicate glass and polymeric quaternary ammonium salt, 2) silicate nucleus formation and silicon-oxygen matrix formation, 3) drying and sorbent fractionation. The further study of adsorption heat transformers on the base of new sorption composite materials for energetic purposes was resulted into hot water supply systems, heat accumulation, air ventilating and conditioning. It was shown that the coefficient of adsorption heat accumulator efficiency achieves 60%. The use of these accumulation systems in different buildings and apartment measuring about 100 m2 has made it possible to save 17 kg equivalent fuel a day, and the temperature is keep about 19 22°C. The installation of adsorption heat and moisture regenerator with energy consumption not more then 1 kW into ventilation system allows us to obtain fresh air flow and keep relative moisture about 50 – 60% and temperature 19 22°C. The new construction of solar adsorption refrigerator was developed. It has additional hydraulic line which allows accumulate the part of heat separated at water sorption and then use it for regeneration of heat-accumulation material. Thus, the influence of weather to regenerative time is decreased. The methodic of calculation of constructive parameters and СОР of solar adsorption refrigerators based on theoretical and experimental study was suggested. In the case of 181 liter refrigeration camera it was shown that mass of heat accumulating material with circulating water is not more than 21 kg, and collector’s surface is 5,6 m2 at reserved coefficient 1,5. The sustained temperature in refrigeration camera during the cycle is about 4 - 9°C.