MODELING THE DYNAMICS OF THERMAL ENERGY ACCUMULATORS AS CONTROL OBJECTS

Abstract

The article defines the relevance of research on options for using heat accumulators in the heat supply system of industrial premises. Typical technological schemes of liquid heat accumulators are considered and shortcomings of existing mathematical models are determined. The technological scheme of a capacitive type battery is selected and analyzed, as the most common in solar heating and hot water systems. It has been established that for a non-stationary process, the thermal inertia of the body reinforcement and thermal insulation cannot be neglected, therefore, the storage tank cannot be considered as a single-capacity object. Based on the analysis of the heat balance of structural elements of heat storage devices, a mathematical model of the dynamics of the accumulator tank as a two-capacity object with lumped parameters is formulated. The resulting simplified mathematical model makes it possible to identify the simulation object (a capacitive type water accumulator). In the considered embodiment, the heat accumulator is used in hot solar water supply systems for preheating water. For use in dual-circuit systems of solar heating and hot water supply, heliolectors with antifreeze are used, and water is heated in heat storage tanks using heat exchangers. The formulated mathematical model of a tank of a combined accumulator with a heat exchanger when used as a liquid heat carrier - antifreeze (to exclude icing of the system), in which, to simplify the model (reduce the order), the heat capacity of the tubes is related to the heat capacity of the heat carrier in the volume of the tubes, and the mass of the body to the mass of liquid in it . For the development and analysis of an automatic temperature control system, the obtained models are a system of nonlinear equations, the solution of which is advisable to carry out in computer environments.