Moskvitina A. Energy efficient seasonal accumulation of heat in solar decentralized heating systems.

Moskvitina A.S. Energy efficient seasonal accumulation of heat in solar decentralized heating systems. - Manuscript. Dissertation for the degree of technical sciences candidate, specialty 05.23.03 – «Ventilation, lighting, heat and gas supply»– Kyiv National University of Construction and Architecture, Kyiv, 2021. The thesis is devoted to solving an urgent problem - the development of an energy efficient system of decentralized heat supply from secondary and renewable sources using a heat storage with solid and liquid heat accumulating materials. Based on the analysis, a number of disadvantages of the existing heat accumulators were noted and a schematic diagram of decentralized heat supply with solar thermal collectors and a seasonal heat accumulator with liquid and solid heat accumulating material was developed. The heat accumulator consists of a body with thermal insulation, in which there is a solid heat-accumulating material, concrete, in the form of a cube with vertical round channels filled with a liquid heat-accumulating material, glycerin, and also in the upper part there is an interlayer filled with a liquid heat-accumulating material. On the basis of mathematical modeling and experimental studies, a set of studies was carried out to determine the thermophysical properties of the developed construction of the heat accumulator and the ratio of the volumes of solid and liquid heat accumulating materials. Based on the results of the research, an algorithm for the operation of a decentralized heat supply system with a system of solar thermal collectors and a seasonal heat accumulator with solid and liquid heat accumulating materials has been developed. A method of engineering calculation of structural elements of a heat accumulator with liquid and solid heat accumulating materials has been developed. And in order to avoid unproductive losses of accumulated heat by the heating system, an indicator of the technical and economic efficiency of the heater was proposed. The results of the work have been implemented in the projects of EDB Panorama LLC, Kyiv. Key words: seasonal heat accumulator, heat accumulating material, accumulation of thermal energy, seasonal heat accumulator design, decentralized heat supply.