Temperature Field Modelas a Factor to Improve a Horizontal Ground Heat Exchanger of a Heat Pump System: Review of Scientific Approaches and the Content of the Analytical Model

The article is devoted to the research of issues related to the organization of control systems for heat pump installations (HPS). HPS is used to use low-potential energy of the environment in the heat supply of buildings. HPS with horizontal ground heat exchangers (HGHE) are of great importance for improving energy efficiency. The efficiency and reliability of HPS with HGHE strongly depends on the state of the soil temperature field. A large number of scientific publications are devoted to modeling soil temperature fields forHGHEparameterdetermination; a significant part of them is devoted to the study of vertical ground heat exchangers. Scientific developments presented in foreign publications on modeling the temperature field of the HGHE location environment are focused on the use of HPS in the cold supply mode and/or in the heat supply mode under conditions of a slight decrease in temperature, which excludes soil freezing. The aim of the study was to apply the existing methods of the analytical theory of thermal conductivity to develop a soil-environment TP model for the placement of a HGHE HPS; the developed model is intended for engineering calculations of the main design HGHEparameters; the model is also applicable to determine the annual specific heat flow as an important parameter in the optimal control system of the HPI. The development of the model is based on the condition of a two-element structure of the soil massif: under the HGHE and above the HGHE; the target parameter is the temperature of the soil mass, depending on the coordinate and time, disclosed through the indicator 'relative temperature rise'; in accordance with the provisions of the thermal conductivitytheory, the relative excess temperature is given for the cases of a semi-infinite body (soil mass under the HGHE) and a slab (soil mass above the HGHE). The proposed model is implemented on the example of two constituent entities of the Russian Federation. The results obtained made it possible to determine the minimum guaranteed possibility of using HPS for heat supply in these climatic conditions. The model presented in the article can be used as a context for further studies of the main parameters of HGHE HPS operation and optimization of HPS operation modes.