The use of alternative energy sources is one of the most important areas of modern energy policy, aimed both at improving the environment and saving traditional fuel and energy resources. Adopted legislative and regulatory acts contributed to the rapid growth of "green" energy in Ukraine. The meaning of the ecological and energy optimization process is not to replace one energy source with another, but economic and industrial transformation, decarbonization and decentralization. 
 A technical solution to the problem regarding the source of alternative energy due to the use of heat in the surface layers of the earth's crust is proposed. At the depth of placement of probes-heat exchangers, which are structurally part of heat pump installations, the soil temperature is practically unchanged throughout the year and is positive. Non-freezing glycol solutions are used to increase the operational reliability of the installations. 
 To study the process of thermal interaction in the zone of placement of heat exchanger probes, mathematical modeling using the finite element method was applied. As a result, a significant array of data was obtained, which reflects the dynamics of temperature fields in different modes of operation of ground-source heat pump installations with vertical probes. 
 Of particular interest is the analysis of temperature fields along the depth of the well. After the seasonal selection of heat - the end of the heating period - the minimum temperature of the soil in the boundary zone of the geothermal probe is not lower than 0 0С. That is, freezing of soil rocks does not occur. 
 In the warm period of the year, due to, for example, the working air conditioning system of the building, the energy source of which is the heat pump installation, regeneration of the primary circuit takes place. The average temperature of the rocks between the probes at the beginning of August is, according to calculations, 6.5 0С. 
 The obtained results of analytical studies were used in the design of a ground heat pump installation for the energy supply needs of a public building with an estimated thermal capacity of 200 kW.