MATHEMATICAL MODELING OF NON-STATIONARY HEAT PROCESSES IN THE GROUND HEAT PUMP SYSTEM

Abstract

In the work, an analytical study of the efficiency of heat pumps using soil energy for heating, taking into account the climatic conditions of theregion of operation, is performed, which meets the tasks of energy saving and allows reducing emissions of harmful substances into the environment. The main attention is paid to increasing the efficiency of utilization of the technical potential of the soil energy source by the heat pump system using vertical soil heat exchangers. A methodology based on use of the mathematical modeling apparatus as a scientifically based toolkit for calculating non-stationary thermal processes, capable of ensuring the stability and reliability of the ground heat pump system in the short and long term, is proposed. The developed toolkit for calculation and analysis of heat exchange processes allows determining the power of the heat flow, which is removed from the soil, taking into account changes in climatic factors, temperature distribution in the soil around the soil tube and along its length over time, schematic and structural features of the soil tubes for further optimization of the parameters of the heat pump system . It was established that the power of the heat flow, which enters the evaporator of the heat pump from vertical soil pipes, depends on a number of influencing factors: the flow regime of the working fluid circulating in the soil circuit; physical properties of the working body; number of soil heat exchangers; temperature distribution in the soil around the soil tube along its entire length, which changes significantly during long-term operation of the system, affecting the course of heat exchange processes in the system elements. The proposed method makes it possible to perform numerical modeling of thermal processes in the elements of the heat pump, to determine the energy efficiency of the ground heat pump system, which is able to reliably provide consumers with heat during a long period of operation, which can be considered an innovative approach to the analysis of prospects for the development of heat pump heat supply.