ANALYTICAL CALCULATION OF THE DEPTH OF TEMPERATURE WAVE PROPAGATION DURING THE CONSTRUCTION OF GEOTHERMAL HEAT PUMP SYSTEMS

• Дата: 2023
• Автори та афіліації: Yu. Morozov — Institute of Renewable Energy of the National Academy of Sciences of Ukraine, Kyiv, Ukraine.; О. Zurian — Institute of Renewable Energy of the National Academy of Sciences of Ukraine, Kyiv, Ukraine.
• Ключові слова: keywords
• Автори: Morozov, Yu., Zurian, О.
• Формат: Стаття
• Мова: Українська
• Опубліковано: Institute of Renewable Energy National Academy of Sciences of Ukraine 2023
• Теми: heat pump; soil storage; heat supply; conversion factor; periodicity; freezing layer.
• Онлайн доступ: https://ve.org.ua/index.php/journal/article/view/421
• Назва журналу: Vidnovluvana energetika

In the process of solving the tasks of soil accumulation and extraction of heat from the near-surface layers of the Earth, there is a need to obtain information about the depth of daily and annual temperature changes in the soil, which determines the layer of the Earth's surface that actively interacts with the Earth's atmosphere. In the cold season, the temperature in it drops, and in the warm season it rises. It is known that the efficiency of the heat pump system depends both on the temperature difference at the outlet of the heat pump condenser and the inlet to its evaporator, and on the stability of the temperature of the heat energy source. The temperature at the inlet to the heat pump evaporator is determined by the temperature of the soil at the place of installation of the thermal energy collector. It is known that the most economically profitable is the installation of geothermal heat exchangers located horizontally in the soil at a shallow depth, due to lower costs for land works and the absence of the need to drill deep wells. At the same time, these systems have the greatest vulnerability to the temperature difference that occurs in the near-surface layers. Therefore, there is a need to study thermophysical processes occurring in the soil under the influence of exogenous factors. It is known that soil temperature has daily and annual periodicity. The degree of heating of the soil depends on its thermal conductivity, which is understood as the ability of the soil to conduct heat from more heated layers to less heated layers. And the course of soil temperature can significantly depend on the vegetation cover of the soil, its nature and height throughout the year. At the same time, heat exchanger-soil systems, the effectiveness of which directly depends on the distribution of temperature in the soil and the factors affecting this distribution, remain insufficiently researched. The main feature of the geothermal heat energy extraction system is the combination of technical and natural elements of such systems. At the same time, the natural source of thermal energy is located in an environment that is not easily accessible for observation. The purpose of the research is to develop an applied methodology as a set of principles and approaches of mathematical modeling based on the proposed mathematical apparatus for analytical calculation of the depth of temperature wave propagation during the construction of geothermal heat pump systems. The basic mathematical apparatus for describing such processes includes differential equations that take into account the dependence of temperature on time and spatial coordinates. Further studies are promising for calculating the possibility of using a solar system to obtain thermal energy to reduce the temperature deviation of the heat carrier at the inlet to the evaporator of the heat pump, which comes from a horizontal ground heat exchanger mounted in the soil below freezing depths and above the neutral temperature layer.