This article focuses on current issues of alternative geothermal heating development, by using low-potential thermal energy of upper aquifers by heat pumping technology. This type of heat supply is sustainable, does not require fossil fuel consumption and does not pollute the environment. In recent years, heat pumping technologies have become common. A lot of heating systems are implemented, using low potential energy in the air, open bodies of water or soil. Although, now, the heat of groundwater in upper aquifers is a more efficient and reliable source of energy for heat pumps. It was tested in this study. The purpose of this study is to impact assessment of the heat regime of the ground upper layers on efficiency of operation of heat pumping units, using groundwater of near-surface horizons. The factors founded, which form the natural heat mode within the studied area, also the correlation established between temperature changes in the horizon and the operation of the heat pump unit, based on the experimental heat pump unit, established by the Institute of Renewable Energy of the National Academy the Sciences of Ukraine. The article presents an experimental hydrothermal heat pump system developed and constructed at the Institute of Renewable Energy of the National Academy of Sciences of Ukraine, which consists of a heat pump and two wells through which water circulation from the underground horizon to the heat pump. The study describes the characteristics of measuring equipment installed on a hydrothermal heat pump system and described developed an interactive scheduling system based on the software product ESM (Engineering Systems Manager) using the programming language FBD (Function Block Diagram | Continuous Function Chart). This software product was used to create the visual system and archival data system that were obtained in the course of this work. The benefits of this study are that the experimental installation uses the thermal energy of groundwater of the Poltava-Kharkov aquifer as the primary energy source. The interval of the productive horizon is 32-57 m. The groundwater level in the horizon is set at about 40 m. In addition, the air temperature between the pipe space of the observation well and the groundwater temperature in the aquifer are monitored. The duration of regime observations was six months, the frequency of measurements – 5-15 seconds. The monitoring results indicate that despite the fact that the productive horizon is at a depth that significantly exceeds the usual depth of the neutral layer for the territory of Ukraine, the for- mation temperature is not stable and its amplitude is 2 oC. According to the authors, the increase in the depth of the surface of constant annual temperatures may be due to local features of the studied area, namely: increasing the absorption surface of solar radiation due to terrain, the presence of lateral heat inflow, the presence of water-saturated layers in the upper part. Consequently, based on the analysis of geological and hydrogeological conditions of the site, as well as technological processes occurring in the installation, the main factors that form the natural temperature of the upper layers of the earth are identified. As a result, the percentage of energy efficiency drop of the installation is calculated depending on the decrease in the temperature of the natural heat carrier in the aquifer. It is established that it is necessary to conduct additional research to assess the environmental impact of the use of aquifers for energy purposes and to ensure the optimal mode of operation of aquifers, which would be as close as possible to their natural regime.

При зберіганні водню найчастіше використовують методи його стиснення або зрідження під дією низьких тем-ператур. Підземне зберігання водню вважається найекономічнішим і найбезпечнішим варіантом його зберігання у великих обсягах. Україна володіє значними запасами калійних, калійно-магнієвих та кухонних солей. Розвідані запаси кам’яної солі в Україні перевищують 2,3 млрд т. У статті визначено основні характеристики п’яти соленосних басейнів, надано перелік родовищ солі, які розвідані, розробляються або перебувають у стадії ліквідації. На підставі аналізу даних літератури визначено критерії вибору ділянок, що придатні для спорудження підземних сховищ водню у соляних покладах. Запропоновано спосіб виробництва водню за рахунок сонячних і вітрових джерел енергії з подальшим його акумулюванням у покладах кам’яної солі. Основною проблемою при цьому є суттєве збільшення температури водню на виході з компресора. Охолодження водню пропонується здійснювати за допомогою поверхневих або ґрун-тових вод.

The article is devoted to a new direction of using the waters of the upper aquifers and open reservoirs for heat and cold supply of residential and public buildings and structures. The theoretical analysis of technologies of construction and features of use of natural accumulators of thermal energy in aquifers is carried out. The general schemes of construction of hydrothermal power systems of closed and open type are described. The hydrothermal experimental heat pump power system developed and constructed at the Institute of Renewable Energy of the National Academy of Sciences of Ukraine consisting of a heat pump and two wells with a depth of 49.5 m and 57.5 m, through which water is pumped or pumped from the aquifer, is presented. The geomorphological, geological and hydrogeological conditions of the study site are analyzed. The peculiarities of the formation of groundwater reserves of the productive horizon are described. Further directions of hydrogeological observations have been determined. The efficiency of the hydrothermal heat pump energy system of the open type is scientifically substantiated. Research methods are described. The characteristics of the measuring equipment and the software which was used for archiving and visualization of the data received in the course of carrying out research work are resulted. The results of experimental researches are presented. A comparative analysis of the efficiency and investment attractiveness of the hydrothermal system of open and closed type, where low-potential thermal energy of water is used as a renewable primary source of thermal energy for the operation of the heat pump was carried out. It is established that the use of renewable low-potential ground energy for the operation of geothermal energy systems is widely used in environmentally safe and economically attractive energy systems. However, the use of hydropower potential in hydrothermal energy systems is not widely used, despite the high technical and economic performance. It is proved that the existing hydrothermal systems are not always adapted to the operating conditions and location of the facility. There is no method of designing open-type hydrothermal systems, methods of conducting preliminary hydrogeological studies of the area planned for the installation of these systems and methods of calculating the parameters of the storage medium. The data obtained during the study are of great scientific and applied importance in the design of hydrothermal energy heat pump systems. In addition, there are prospects for further research into the possibility and effectiveness of using the aquifer as a natural heat accumulator to stabilize the generation of energy from renewable sources, regardless of climatic conditions and time of year.