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Recently, many problems, such as the energy crisis and environmental pollution, have made the use of alternative energy in the production of electrical and thermal energy relevant. Because alternative energy sources are environmentally friendly, accessible and inexhaustible. In the most advanced and developed countries, heat pump systems are used for heating, ventilation and cooling of buildings. The article examines the efficiency of operating modes of collector-type geothermal heat pumps in the Karabakh economic zone. The heat supply scheme and all characteristic parameters associated with this scheme were calculated using the GeoTSol modeling program. The GeoTSol simulation program is one of the modern simulation programs for planning and designing heat pump systems. As an example, a private residential building located in the city of Khojavend was studied. A monovalent collector-type heat pump system provides hot water supply and heating for a private home. For comparison, a diagram of 4 types of collector-type heat pump systems is proposed. Seasonal performance coefficients, energy consumption, losses, solar energy share, efficiency, etc. were calculated by computer simulation of the entire heat pump system for each cycle and compared with each other. A circuit operating in the most efficient mode has been determined. [ABSTRACT FROM AUTHOR]

Automation of industrial heat supply points using serial domestic automatic regulators, sensors, microprocessor devices and computer programs is considered. A technological scheme for automating an open heat supply system of an enterprise with a corrective mixing pump and a network water flow regulator are developed. [ABSTRACT FROM AUTHOR]

To design and analyze structures and materials that are subjected to changing thermal environments, it is essential to take into account thermal shock events, which are characterized by rapid and dramatic changes in temperature. In this study, a new thermal conductivity model was used to consider the thermal response of an isotropic thermoelastic medium heated by a moving heat source. This model uses memory-dependent higher derivatives and the concept of the Moore–Gibson–Thompson equation. Using the vector-matrix differential equation form, the basic equations are formulated. The model was applied to consider the thermomechanical behavior of a semi-infinite thermoelastic solid. In the field of the Laplace transform, the technique known as the eigenvalue approach deals with the mathematical formulation and solution of the problem. The inversions of Laplace transforms are found numerically using the Honig and Hirdes approximation approach. A graphical representation is provided showing the fluctuation in temperature, displacement, and stress distributions with changing values of kernel functions and higher orders, as well as the velocity of the heat source. Tables are also included to show comparisons and a full analysis of thermomechanical responses and how they affect the way system variables behave. [ABSTRACT FROM AUTHOR]

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The use of machine learning methods to control heat supply systems is a pressing issue worldwide. The aim of the work is to develop methods for intellectualizing the operating modes of individual heat supply units (IHU) to improve their efficiency and reliability. To achieve this goal, the following tasks were solved: creating and debugging methods for diagnosing IH operating modes; using the cluster analysis method, in particular the K-means algorithm, to identify pre-emergency situations at an early stage; analyzing the relationship between outdoor air temperature data and the pressures of direct and return network water in IHU operating modes using Novosibirsk as an example. The most important results of the work include dividing the measured parameters into five clusters, each of which characterizes a certain IHS operating mode. This was confirmed by the "Elbow Method", which determined the optimal number, which made it possible to significantly improve the forecasting of emergency modes. Studies have shown that a sharp increase in outdoor temperature leads to an increase in the pressure of direct network water, which can cause accelerated wear of heating networks due to the peculiarities of weather-dependent automation regulation. Introducing additional parameters into the initial data, such as the service life of heating networks and weather conditions, can improve the accuracy of forecasts. The significance of the obtained results lies in the possibility of early detection of emergency and pre-emergency modes of IHU operation, which helps prevent accidents and reduce repair and maintenance costs.

Background. Soybean is the main supplier of complete vegetable protein and oil. Prior to the emergence of new early-ripening cultivars, this crop was not cultivated in Irkutsk Province. Its introduction into the area requires a detailed study of agricultural practices, primarily the choice of optimal sowing dates. Materials and methods. Soybean cv. ‘Barguzin’, late-ripening under the conditions of Irkutsk Province, and early-ripening accession 15 served as the research objects. Field studies were carried out in 2019–2021. There were four sowing dates, from the first ten-day period of May through the first ten-day period of June. Results and conclusion. Cv. ‘Barguzin’ appeared highly productive under the climate of Irkutsk Province (its average seed yield in 2019–2021 was 2.7 t/ha), but its productivity was significantly influenced by weather conditions and sowing dates (seed yields varied from 1.4 to 3.6 t/ha). The optimal sowing times for this cultivar are the first and second ten-day periods of May. Early-ripening accession 15 was characterized by more stable yield values in the studied years (average productivity was 2.4 t/ha, minimum 1.9 t/ha, and maximum 3.2 t/ha). The preferred sowing times for this accession are the second and third ten-day periods of May. The case study of two soybean genotypes differing in maturation schedules revealed the need for individual selection of sowing dates. It was shown that the early-ripening soybean genotype imposed less stringent requirements on the choice of sowing dates.

The article presents the scientific results of a study assessing agroclimatic resources in agricultural landscapes located in various natural zones of the Turkestan region of the RK (Republic of Kazakhstan). The research methods included classical and modern methods of mathematical statistics using digital technology and time series graphs to develop a mathematical model for climatic and hydrological indicators. Assessment of changes in indicators of agroclimatic resources in agricultural landscapes for 1941–2020 showed that the sum of air temperature, evaporation from the water surface and radiation balance of the daytime surface, characterising the energy resources of landscapes, increased by 10–15%, which contributes to increase in the total water consumption of agricultural land by 10–12%. Meanwhile, the decreasing tendency of the amount of precipitation by 5–10% in all natural climatic zones of the region has become one of the factors leading to a decrease in the natural moisture supply of the soil and vegetation cover of landscapes by 10–15%, acting as important environment-forming and ecological functions. The combined impact of these environment-forming factors has become the key reason for the increase in the deficit of agricultural land water consumption by 15–20%, the reduction of solar energy costs for the soil-forming process by 10–15% and the increase of the climate aridisation, and has become a signal for the need in the safety of agricultural activities, requiring the development of a set of adaptive measures to mitigate this process in the region.

The article deals with the issues of the impact of the quality of consumers' heat supply on the sustainable development of the urban areas infrastructure focused on the implementation of the United Nations Program on Human Settlements (UN-Habitat). A group of five countries of Central Asia has been studied, the quality of heat supply to consumers of which has long been ensured through centralized systems. An analysis of the heat supply quality in these countries showed that the main advantage of district heating, cogeneration, is losing its usefulness for consumers due to the significant accumulated wear and tear of heat supply systems. Quantitative dynamic characteristics of the heat supply facilities functioning are considered. A set of indicators for evaluating investment projects aimed at improving the heat supply quality is presented, that made it possible to propose rating indicators of heat supply interconnected with the Sustainable Development Goals (SDGs).

An analysis of changes in surface air temperature was carried out at stations in the Saratov region from 2002 to 2022. The study is based on the analysis of materials from longterm hydrometeorological observations carried out through the Roshydromet network, which reflects the reliability of the results obtained. The article presents a comparison of average monthly temperatures for a given period with temperature norms. A map of temperature changes was constructed. The duration of the growing season for plants was calculated and analyzed. With the help of agroclimatic zoning of the country according to D. I. Shashko there was established which zone the Saratov region belongs to and which agricultural crops are best cultivated in the region.

The article presents the scientific results of a study assessing agroclimatic resources in agricultural landscapes located in various natural zones of the Turkestan region of the RK (Republic of Kazakhstan). The research methods included classical and modern methods of mathematical statistics using digital technology and time series graphs to develop a mathematical model for climatic and hydrological indicators. Assessment of changes in indicators of agroclimatic resources in agricultural landscapes for 1941-2020 showed that the sum of air temperature, evaporation from the water surface and radiation balance of the daytime surface, characterising the energy resources of landscapes, increased by 10-15%, which contributes to increase in the total water consumption of agricultural land by 10-12%. Meanwhile, the decreasing tendency of the amount of precipitation by 5-10% in all natural climatic zones of the region has become one of the factors leading to a decrease in the natural moisture supply of the soil and vegetation cover of landscapes by 10-15%, acting as important environment-forming and ecological functions. The combined impact of these environment-forming factors has become the key reason for the increase in the deficit of agricultural land water consumption by 15-20%, the reduction of solar energy costs for the soil-forming process by 10-15% and the increase of the climate aridisation, and has become a signal for the need in the safety of agricultural activities, requiring the development of a set of adaptive measures to mitigate this process in the region. [ABSTRACT FROM AUTHOR]

This article examines the bioclimatic potential (BCP) (according to S.A. Sapozhnikova) and agroclimatic characteristics of the Central Chernozem Region, including the Oryol oblast, with spatiotemporal trends of their variability analyzed from 1980 to 2021. In the early 2000s, compared to the late 20th century, there was a 10% increase in the BCP, a 13% rise in the sum of active temperatures, and a 6% longer active growing season. Furthermore, shifts in the isolines of the sum of active temperatures and the hydrothermal coefficient (HTC) occurred. The active temperature isotherm of 3000°C moved northward, and it is now running through the Belgorod and Voronezh oblast. As a result of the observed hydrothermal conditions, a significant part of the Central Chernozem transitioned from the zone with sufficient moisture (1.3 ≥ HTC > 1) to an arid zone (1 ≥ HTC > 0.7). The overall growth of the BCP in the Central Chernozem Region can be associated with a considerable rise in the sum of active temperatures and a reduction in moisture supply.

This article describes the history of the industrial development of the essential oil industry and the prospects for cultivating such essential oil crops as dill and coriander, including in the territory of Transbaikalia. Data are provided on the volume of essential oil production in Russia in different years. The noted morphobiological features of dill and coriander suggest the possibility of obtaining a high yield of fruits when they are cultivated by agricultural producers in the dry steppe zone of Transbaikalia. For the first time, in the conditions of the dry steppe zone of Transbaikalia, field research was carried out to study the effectiveness of some agricultural practices for cultivating zoned varieties of dill and coriander. The results of three years of research (2021-2023) on the formation of fruit yield of plants of the Umbrella family with a one-year development cycle - dill (Gribovsky, Lesnogorodsky varieties) and coriander (Karibe variety) in the driest soil-climatic zone of Transbaikalia are summarized. It was revealed that the heat supply of the growing season affects the formation of the fruit yield of the studied crops. The highest fruit yield was obtained from the Gribovsky dill variety at an average sowing time, and from the Lesnogorodsky variety when sowing early. At the same time, the Gribovsky variety is superior in yield to the Lesnogorodsky variety. The coriander variety Caribe provided the maximum fruit yield at a late sowing time in all years of research. In general, the soil and climatic conditions of the dry steppe zone of Transbaikalia make it possible to obtain a harvest of aromatic dill and coriander at the level of other regions of Russia, which determines the future development of essential oil crop production in our region.

Introduction. Further development of methods of calculation the thermal regime of premises at emergency modes of operation of heat supply systems is actual. The aim of the research is to find an approximate analytical dependence of the air temperature in the building premises on time in conditions of a sharp cold snap with further linear decrease in outdoor temperature. As a scientific hypothesis, the position is put forward about the possibility of expressing this dependence through exponential functions using as an argument the square root of the time since the beginning of cooling.Materials and methods. The basic differential equation of the convective heat balance in the room, including the most significant components of the heat flow is used under the assumption of the linear character of the outdoor temperature decrease over time, taking into account the peculiarities of the temperature wave propagation in massive enclosures in the initial period of time. The Bernoulli method for the linear differential equation of the first order is applied by representing the solution as a product of two functions.Results. The analytical expression for the approximate dependence of the temperature change in the room at a sharp cold snap with the continuation of the further decrease of the outdoor temperature according to the linear law is found. The obtained refinement of this dependence is evaluated in comparison with the solution for the case of constant outdoor parameters on the example of one of the rooms in a residential building for the climatic conditions of Moscow.Conclusions. The structure of the obtained solution is analyzed and it is shown that the continuation of external cooling leads to acceleration of room cooling, and the solution for the cooling mode previously considered by the author at constant outdoor air temperature is its special case. It was found that the continuation of external cooling additionally leads to some straightening of the internal temperature graph, because the growth of heat loss through inertial-free structures begins to compensate to some extent for the cooling slowdown associated with the release of accumulated heat from massive encloses.

The paper discusses the circumstances and technical solutions that contribute to the integration of electrical and thermal networks of urban neighborhoods within the framework of a surplus of electricity generating capacities arising from the imbalance in the development of energy generation and consumption, stochastic processes of market economy development, the transfer of energy-intensive industrial production to other countries, the desire to diversify fuel energy resources, passion for the construction of energy sources for alternative energy resources in counterbalance to traditional energy facilities without taking into account all aspects of the interaction of the former with the environment, etc. With regard to district heating systems of electrical and thermal networks of urban neighborhoods, the use of hybrid heating points is achieved, which, unlike standard solutions, are equipped with electric boilers, thermal accumulators and heat pumps. According to the time of use of generating capacities, preference should be given to options for covering the hot-water load. Based on the average daily load, the power usage time in this case lies in the range of 6000–6500 hours / year. When choosing the capacity of the equipment, it should be borne in mind that the daily load of hot water supply is extremely uneven and also depends on the day of the week, while the maximum load exceeds the average daily by 2.5 – 3.0 times. When integrating electricity and heat supply systems, it is advisable to consider options for only night-time electricity consumption or night-time consumption plus consumption during the hours of daytime failures of the electricity consumption schedule. If during the new construction the power of the electrical network may vary depending on the selected option, then during the modernization of the heat supply system, the problem is solved if there is a limitation on the available electrical power. Therefore, the definition of these restrictions is a separate issue. In comparison with the direct consumption of electricity for the needs of heat supply, which is a priori energetically and economically inefficient, the use of hybrid systems in heat supply allows us to solve the multifunctional task of increasing the reliability of energy supply and the stability of the functioning of the power system, which is primarily achieved by solving the problem of balancing the capacity of production and energy consumption from the position of aligning schedules of energy generation and consumption.

Introduction. Heat exchangers are important equipment in modern heat supply. This equipment is very common. Modernization of shell-and-tube heat exchangers is an important direction. The purpose of modernization is to increase the heat transfer coefficient. A heat exchanger which tubes are equipped with plates was developed. Cylindrical turbulators (ribs) are located on the plates. The experiment is important for the development of a new heat exchanger. The experimental conditions correspond to the real heat supply system.Materials and methods. The full-scale stand was used for the experiment. The stand represents an independent heating system of the building. The planning of the experiment is based on the temperature schedule of the boiler house and the temperature schedule for the consumer. Mathematical processing of the results was carried out.Results. For a heat exchanger (with turbulators), the values of the heat transfer coefficient were obtained at different outdoor temperatures during the heating period. The dependences of the heat transfer coefficient on the temperature difference are obtained. This was done at coolant velocities in the annular space of 0.16 and 0.32 m/s. Discrepancies are adequate, statistically significantly describe the results of the experiment. The heat transfer coefficient of the heat exchanger (with turbulators) turned out to be greater than that of the serial one. This parameter is 22 % more at a speed of 0.16 m/s, 23 % more at a speed of 0.32 m/s on average for the heating period.Conclusions. The heat transfer coefficient increased for the heat exchanger with turbulators by an average of 23 %. The turbulence of the coolant affects this increase. The dimensions will be much smaller for such a heat exchanger than for an apparatus with smooth tubes. Tube with cylindrical turbulators is recommended for use in different equipment. This can be used in shell-and-tube heat exchangers, air heaters, heaters, economizers.

In the process of solving the tasks of extracting low-potential environmental heat from open bodies of water when using heat pump systems with collectors immersed in the body of water, there is a need to obtain information about the depth of temperature changes in the body of water, which determines the layer of water 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 on both the temperature difference at the outlet of the heat pump condenser and the inlet to its evaporator, and 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 medium at the place of installation of the thermal energy collector. And taking into account the fact that the collector of the hydrothermal system usually sinks to the bottom of the reservoir, the task of determining not so much the change in water temperature in the reservoir itself as the temperature at the watersoil boundary, at the bottom of the reservoir, that is, the study of thermo physical processes occurring in water under the influence of both exogenous and and endogenous factors. The main feature of the hydrothermal thermal energy production 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 paper provides a description of the developed experimental hydrothermal heat pump system and the research methodology. Field studies were conducted to analyze the influence of bottom heat flows on the daily regime of a small open water body. Changes in the temperature of water and the bottom of open water bodies in the city where the experimental system is located are practically determined. It is shown that as a result of taking into account the heat exchange with the bottom, the temperature at the depth of the reservoir increases and decreases near the surface. This leads to an increase in the turbulent flow from the atmosphere and a decrease in heat output due to long-wave radiation, as a result of which the average temperature of the reservoir increases. The mathematical apparatus for analytical calculation of the depth of temperature wave propagation in water during the construction of hydrothermal heat pump systems is described. The basic mathematical apparatus for describing such processes includes differential equations that take into account the dependence of temperature on time and spatial coordinates. [ABSTRACT FROM AUTHOR]

Depletion of the world's fuel and energy resources, which causes an inevitable increase in energy prices, both on the world market and in Ukraine, has exacerbated the problem of the introduction of energysaving technologies and put research aimed at the effective use of renewable energy sources for the purposes of energy supply into a number of strategic tasks state. The paper analyzes existing heat supply systems and ways to increase the efficiency of using existing energy resources and reduce emissions of harmful substances into the environment. The expediency of a comprehensive approach to the implementation of energy-efficient technologies in the heat supply system, taking into account the peculiarities of the operating modes of buildings and engineering life support systems, is shown. Based on the analysis of existing mathematical models and methods of calculating the operating modes of various elements of the combined heat supply system using renewable energy sources (solar collectors, heat pumps, heat accumulators, etc.), mathematical models of the operating modes of the specified systems are given. On the example of a separate building of public purpose (educational building), the calculation of the operation modes of the microclimate engineering systems was carried out taking into account the operating modes of the building, and on the basis of the available pilot plant, a study of the operation of the combined heat supply system using renewable energy sources and the use of heat accumulators was carried out to coordinate the generation modes and heat consumption by the building. On the basis of the conducted research, the distribution of the shares of energy savings from each stage of modernization of microclimate engineering systems and general thermal modernization of the building using both external thermal insulation and internal shielding of massive walls was obtained. [ABSTRACT FROM AUTHOR]

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The current work aims to investigate the interaction between thermal, magnetic, and elastic phenomena in a homogeneous and unbounded material that includes a spherical cavity. A laser beam with a Gaussian distribution was used to expose the solid thermal medium, thereby bringing a source of heat into the system. The study is grounded in the expanded theory of thermoelasticity without energy dissipation, which considers the interconnection between thermal, elastic, and magnetic phenomena. This theoretical framework serves as a basis for understanding the interactions and behaviors of thermal and mechanical processes within an elastic material. The system was analyzed using a direct approach, employing the Laplace transformation method to provide solutions for the system's equations. This methodology enables the computation and presentation of precise equations for several domains of concern, such as displacement, temperature, and thermal stresses. The discussion and analysis focused on a copper-based material, and graphical representations were used to demonstrate the behavior of the researched physical fields. These graphical representations aid in comprehending the development of displacement, temperature, and thermal stresses within the material caused by the laser beam and the interplay between thermal, magnetic, and elastic processes. The results demonstrate that the laser pulse parameters have a significant impact on the temperature and thermal stress distribution, thereby influencing the thermo-mechanical reactions of the solid medium. Ultimately, this study enhances our comprehension of the intricate behavior and interplay of thermal, magnetic, and elastic phenomena in thermoelastic materials.

A grape plant is capable to adapt, grow and produce crops in different environmental conditions. At the same time, agro-climatic conditions of grape growing area have a significant effect on the product quality. Environmental climatic conditions of Crimea contribute to cultivating grapes from very early to late ripening varieties. Diverse range of abiotic conditions allows choosing an optimal terroir for the formation of necessary grape conditions depending on the application target. Significant spatial climate variability within the region makes it possible to evaluate the impact of environmental factors on biosynthetic and accumulative properties of grapes. The purpose is to study changes in the profile of carbohydrate-acid complex of wine grape varieties under the influence of agro-ecological growing conditions. Materials and methods. Study objects were white and red grape varieties growing in various viticulture and winemaking regions of Crimea. A research for grape plant response to the variability of environmental factors basing on a long-term comparative study of chemical composition of its fruits, determining the varietal biochemical identity and technological properties in a particular region, was carried out. Results and conclusion. As a research result, the cumulative effect of agro-ecological factors on the accumulation of components of carbohydrate-acid grape complex was established, and in particular years it was possible to identify the dependence between their quantitative content and individual environmental factors. Accumulation of the mass concentration of sugars in grape berry directly correlated with the Huglin index value (r = 0.7). With regard to the mass concentration of titratable acids, an inverse correlation was revealed with the Winkler index value (r = -0.59). A comparative analysis of the results shows that one grape variety grown under different climatic conditions may show different ability to synthesize the components of carbohydrate-acid complexes, determining its suitability for various output production. There is a direct correlation of the mass concentration of sugars on the average air temperature for the last month before harvest (r=0.70) within the variety.

The successful development of the Arctic zone of the Russian Federation is directly related to the reliable and efficient operation of local heat supply systems, including those with minimal anthropogenic impact on the environment. Today, the Arctic zone of the Russian Federation uses mainly imported fossil fuels for heat generation, most of which (with the exception of coal and wood in some places) are delivered from other regions of Russia, which is associated with great financial difficulties and complicated logistics of fuel delivery to consumers. On the example of Teriberka settlement, located in the Murmansk region on the coast of the Barents Sea, it is shown that one of the solutions to these problems can be the use of wind turbines for heat supply needs together with the local boiler house, operating on organic fuel. The main effect from the use of wind power plants is expressed in the reduction of the boiler house participation in covering the heating load schedule of Teriberka settlement by 7580% and, accordingly, by the same amount in saving fossil fuel consumed at the boiler house, as well as in reducing the negative impact on the natural environment.

One of the most important areas for improving Russian economy under the influence of sanctions pressure is to increase the level of energy efficiency in the consumption of fuel and energy resources. The aim of the study is to study the place and role of the Russian economy in the process of forming the world fuel and energy balance. An analysis of the data on the production and consumption of fuel and energy resources by Russia emphasized that the country occupies a leading position in terms of reserves, production volumes, consumption and exports of global fuel and energy resources, while the efficiency of energy consumption in the country is significantly behind the world average, which negatively affects the internal economic processes taking place in the country and requires the search for solutions to increase the level of energy efficiency. Research analyzes analyzes the volume of thermal energy consumption in Russia in comparison with the global scale, as a result it was revealed that the annual volume of thermal energy consumption in Russia is 11 times more than, for example, in Germany, 12.5 times more than in the USA, 12.7 times more than in Kazakhstan, which underlines the significant contribution of the heat supply industry to the lag in the level of energy efficiency of the Russian economy from the indicators of most countries. Analysis of the statistical data of average temperatures in various countries of the world, as well as the federal districts of the country, revealed the influence of the climatic factor on the volume of thermal energy consumption in Russia, which determines the impossibility of excluding the consumption of thermal energy to maintain the functioning of the Russian economy. The main result of the study is the revealed high role of the Russian economy in shaping the global fuel and energy balance, as well as the need to increase the level of energy efficiency of fuel and energy consumption. The materials suggest the improvement of alternative replacement models for consumed primary and secondary fuel and energy resources. As an energy replacement resource, it is proposed to use electric energy in the system of combined district heating of industrial areas. The use of electric boilers makes it possible to increase the energy efficiency of integrated energy supply, enhance the environmental friendliness of heat supply, and reduce the cost of the economy for centralized heat supply of individual territories.

The domestic sphere of heat supply, which is currently in decline due to the critical technical condition of Russia’s heat sector, requires measures to modernize it. It is necessary to strive for innovative development of the sector. The introduction of innovations can significantly accelerate the modernization processes, as well as ensure the fulfillment of environmental safety property of heat supply, that is, the ability to influence the reduction of environmental damage to the environment during the operation of heat supply facilities. The main entity implementing modernization processes and innovative solutions in heat supply systems is a unified heat supplying organization, which is legally assigned the function of strategic development of the heat supply system in its subordinate territory. The issues of modernization and innovative development of heat supply systems involve the need for significant investments in these processes. In this regard, the author’s approach to assessing the effectiveness of introducing innovations into a single heat supply organization and the heat supply system assigned to it has been formed using criteria that allow jointly assessing both economic efficiency and environmental and social effects of decisions taken and innovations implemented.

Based on the analysis of thermohydraulic processes and the structural and functional structure of the proposed system of heat and cold supply of buildings, a multifactorial dependence of the actual conversion coefficient was established to assess the efficiency of transformation of the heat taken from the soil massif and ventilation air. It allows modeling the individual influence of the initial parameters and operational modes of the system in the search for rational conditions for the highly efficient use of energy flows for heat and cooling supply of buildings during the corresponding periods of the year. The results of a qualitative assessment of the multifactorial interrelation of the actual conversion coefficient substantiated the possibility of energy efficient operation of the analyzed system, which is provided under the design conditions of the heating period when the ratio of circulating flow rate through the evaporator and condenser of heat pump is higher than 1.8, which is rational for sports, recreation, shopping and entertainment complexes. The improved structural and functional arrangement of the system based on a binary low-temperature source increases the efficiency of vapor compression transformation of energy flows, indirectly confirming the advisability of maximizing the use of the energy potential of ventilation air during the year with a corresponding accumulation of excess heat in the soil mass, and, consequently, the possibility of reducing the depth of expensive wells or the number of probe heat exchangers.

The article deals with the most important problems of the communal complex in the subjects of the Far North and the Arctic zone of the Russian Federation. The main attention is paid to the aspects of formation of territorial heat supply systems, which are the basic components of the infrastructure of life support in harsh polar natural and climatic conditions. The impact of the growth of utility tariffs on the structure of consumer spending of households in the northern and arctic regions is assessed. It is shown that the state of the municipal energy sector determines the formation of the socio-economic environment and investment attractiveness of the Arctic municipalities. Its renewal and modernization are the main conditions that contribute to reducing the rate of migration outflow of the local population, increasing industrial production and the state military–strategic presence in this important macro-region. Despite the predominance of energy sector specialization in the list of leading industrial enterprises, the presence of the necessary fuel and raw materials base and increased inflow of investment resources in the energy sector, there is further obsolescence and reduction of fixed assets of municipal energy supply units as well as the highest level of utility consumer costs in comparison with all-Russian indicators. The conclusion about the loss of previously available territorial infrastructure advantages of the Russian Arctic regions is substantiated: there has been a reduction in the total number of heat sources, territorial energy production, the length of heat communication networks. The increase of these energy threats is a factor limiting the socio-economic growth of Russia’s northern and arctic territories.

The article notes the lack of investment in heat supply market, which leads to increased wear and tear of both heat sources and heating networks, huge heat losses and non-competitiveness of district heating systems. A proposal is being considered to implement a new model of the heat market in all regions of Russia and to switch from direct state regulation of tariffs for heat energy (capacity) to contractual tariffs, the maximum level of which is determined by the “alternative boiler house” method. However, for those regions where the existing tariffs for heat energy (capacity) are higher than the established limit levels using the “alternative boiler house” method, the authors propose the use of other approaches and methods of tariff regulation, in particular, examples, advantages and disadvantages of using energy service contracts, tariff regulation based on method of return on invested capital, new legislation in terms of obtaining long-term loans for the modernization of infrastructure from the National Welfare Fund and the Housing and Utilities Reform Assistance Fund.

The paper considers the use of exhaust gas heat in modular power plants. In this regard, fuel consumption at power plants will decrease, efficiency of power plant will increase the emission of harmful gases into the atmosphere and environmental burden will reduce. [ABSTRACT FROM AUTHOR]

The article presents a proposal for a comprehensive methodology designed to increase the energy self-sufficiency and overall resilience of rural areas. The methodology aims to maximize the synergy and economic benefit of the agrovoltaic system with the cultivation of the energy crop Miscanthus x giganteus and its use for energy production in CHP sources within the local energy community. Primary data from Miscanthus × giganteus cultivation from long-term field trials and commercial plantations and initial agrovoltaic experiments were used. The analysed data show the high resistance and adaptability of Miscanthus × gigante us to climate change and confirm its expected long-term high yields of around 15 t DM ha−1 y−1 with a Higher Heating Value of 17–19 GJ t−1. The application of the methodology to a case study in the Czech Republic shows a reduction in electricity consumption by more than 40% (2 GWh) and a reduction in thermal energy consumption by more than 15% (4 GWh). The technical-economic analysis shows the high potential, financial and non-financial benefits of local production of energy fuels from biomass as part of subsequent production and energy distribution in the agrovoltaic field. • A comprehensive energy system design methodology for increasing local energy self-sufficiency is proposed. • The methodology assesses the energy potential of Miscanthus x giganteus. • Agrovoltaic technology, local heat distribution system and combined production of heat and electricity are investigated. • Innovative energy projects operated within the framework of Energy Community support energy transformation. [ABSTRACT FROM AUTHOR]

Energy sources and mechanisms supplying energy to the oscillating system of an ejector pulsejet engine that supports gas acoustic self-oscillations, are researched. The study is carried out using experimental, numerical, and analytical methods. [ABSTRACT FROM AUTHOR]

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The article explores issues related to the reconstruction of buildings of the old housing stock. For the first time, an analysis of the physical state of operated buildings of mass series built in the 1970s and 1980s is given, on the basis of which a conclusion was made about the possibility of mass modernization with the addition of additional floors. The article substantiates the possibility of performing work on the compaction of the existing building with the addition of additional floors in 5-storey buildings without increasing the load on the existing engineering networks. The article shows that such an approach to the transformation of the urban environment fully satisfies the principles of sustainable development of the city.

The aim of the study is to define the essential characteristics of startups, identify the features, trends and prospects for their development in the global energy sector as well as development opportunities in Ukraine. Based on the carried out research, it is shown that today startups are a catalyst for economic development, the processes of their creation in the world are developing dynamically. The importance of the energy sector in the development of startups due to the importance for states and humanity aiming at achieving the goals of the transition to clean energy, also the need to ensure energy independence and security of the countries of the world, and their national security in particular, is determined. An understanding of the essence of the concept of «startup» has been formed. It is found that startups are based on low-tech, high-tech and deep-tech innovations, their features are examined. Specific features of the energy sector that determine the processes of technological changes in the sector and affect the peculiarities of creating and implementing startups, the dynamics of their development and risks are highlighted. Quantitative indicators of the development of startups (including those connected with energy sector), as at the global level so by individual countries, their structure according to the directions, features of the development of startups in the fields of «clean» and «digital» energy are researched. The experience of individual countries in building an effective startup ecosystem is considered. It is substantiated that in the current conditions the development of the country requires the use of various instruments on the part of national policy for the formation and development of an ecosystem of startups, ensuring the appropriate institutional environment. This will create the basis for economic growth, which is extremely important for Ukraine in the context of post-war economic recovery. It is determined that large-scale destruction in the energy sector substantiates the high importance of the development of startups in it, which can be helpful in covering certain needs, for example, in liquid fuel, efficient heat supply, etc.

The purpose of the article is to substantiate the feasibility of an integrated approach to the implementation of measures for the restoration and modernization of housing stock and heat supply objects. On the conditional example of heat supply of a heated quarter (which means a small number of residential buildings to be heated, a local boiler room and local distribution heat networks), various modernization options are considered: separate thermal modernization of buildings, modernization of heating networks, modernization of the boiler room, and options for simultaneous modernization of all elements of the chain: production-supply-consumption of heat energy (complex modernization of the heated district). It is proved that precisely a comprehensive modernization, which involves a simultaneous production, coordinated in terms of time and volumes, supply and consumption of heat, is an effective instrument for improving efficiency in the sphere of heat supply and heat consumption. The complexity of modernization in this example involves thermal modernization of buildings in the heated district (with a decrease in heat consumption by 40%) with the simultaneous modernization of heat transmission networks (with a decrease in heat loss when supplied from 20% to 5%) and modernization of the boiler room (with an increase in the efficiency quotient of boiler equipment from 88% to 93%). The implementation of such a project is economically feasible for all participants: consumers reduce the cost of paying for heat supply services by 49%, and the supplier and producer of heat with a slight (up to 6%) increase in heating tariffs provide break-even activities and receive a larger investment resource in the form of a larger amount of depreciation. At the national level, the proposed mass complex modernization of heated districts can almost halve the consumption of natural gas by municipal heat and power engineering and to the same extent reduce emissions of harmful substances into the atmosphere. In addition, it becomes possible to significantly reduce the amount of subsidies from the budget for the payment of housing and communal services by the population.

This work is devoted to determination a generalized indicator for a preliminary assessment of the conditions for increasing the efficiency of modernized systems of centralized and decentral-ized heat supply using heat pump technologies. This goal is achieved through a critical analysis of the results of the actual state of pipelines and equipment, known approaches to the recon-struction of heat supply systems and the establishment of a generalized indicator of the condi-tions for increasing the efficiency of using primary fuel energy. This made it possible to formu-late a generalized approach to the modernization of heat supply systems with the introduction of heat pump technologies. The most important result of the study is the established generalized dependence of the assessment of the increase in the efficiency of heat supply systems on the initial conditions of regime parameters with the rationale for the feasibility of modernizing dis-trict heating systems based on the diverse phased introduction of heat pump technologies at all stages: generation, transportation, distribution, conversion and controlled consumption of heat by subscriber system. The significance of the obtained research results lies in the fact that the proposed approach to the modernization of centralized and decentralized heat supply systems based on heat pump installations with real conversion factors in the range (3--5) with an increase in the available heat potential is to increase the efficiency and expand the use of heat from pri-mary fuel with its savings of 1-2.7 times.

The combined use of low-potential soil heat and air flows in heat pump heat supply systems allows for its regulated redistribution in the processes of customers’ consumption. Herewith, the intensity of energy extraction by the soil heat exchanger decreases, excess heat is accumulated with a decrease in the depth of wells, and the costs of installing and operating probe heat exchangers are also reduced. An improved version of the conceptual arrangement of a vapor compression system for heat and cool supply of buildings based on the integrated heat of soil and ventilation air has been developed. Its distinguished features are the possibility of automatic redistribution of generated heat flows in the subsystems of customers’ heat consumption and accumulation of excess part in the soil mass. When the system is operating in the warm season with the extraction of heat only for hot water supply, there is a more intensive accumulation of excess heat of the ventilation air in the soil mass, which restores its temperature in the accumulation mode for further use with the coming of the heating period. Multifactor analytical dependences of the heat flows of the main equipment have been established, taking into account the initial parameters and operating conditions of the structural subsystems for the extraction, transformation and consumption of heat, which are the basis for determining the energy potential of vapor compression heat and cold supply using a binary low-temperature source.

The article is aimed at studying the current mechanism of the State regulation in the field of heat supply, identifying directions for its reform and developing proposals as to the formation of regional heat energy markets. To achieve this aim, the existing procedure for regulating economic activity in the field of heat supply, the mechanisms of functioning of electricity and natural gas markets are analyzed, the principles of functioning of regional heat energy markets are formulated. The study analyzes the content of the concept of «energy carriers market» (on the example of electric and heat energy and natural gas), as well as the basic principles of the functioning of national and regional markets of heat energy carriers. The current mechanism of the State regulation of economic activity in the field of heat supply and natural gas and electricity markets is examined. The direction of improving the regulation of economic activity in the field of heat supply is substantiated – further decentralization of managerial functions and concentration of powers at the level of local communities; creation of regional heat energy markets, which should be in the operational and strategic management of local self-government. The composition of instruments of the State regulation of the regional heat energy market is proposed. The result of the study is the development of proposals for the classification and composition of such groups of the State regulation instruments: regulatory (licensing, establishment of mandatory rules of economic activity, approval of standard forms of contracts, etc.), tariff (approval of the methodology for substantiating the level of tariffs), financial (provision of preferential economic conditions), and monitoring. Prospects for further research on this topic are: development of a model of the regional heat energy market along with a road-map for its construction; development of methodological provision necessary for the functioning of the regional heat energy market; substantiation of directions for improving domestic legislation on the regulation of economic activity in the field of heat supply

The paper presents a model of a solid fuel boiler with the improvement of the locking mechanism to increase its efficiency, which in turn will increase the savings and ecological safety of such a boiler. The given calculation of the volume of dry gases, theoretical volume of nitrogen and the volume of water vapor, which makes it possible to determine the content of oxygen in the air and other elements in the fuel. Given a 3-d model of solid fuel boiler by means of FlowSimulation software. Based on the test results, the amount of combustion products leaving the chamber was shown. The research results show that, depending on the size of the boiler elements, there is no ventilation in the room where the boiler is located, and after an hour of operation, a long stay of a person may cause health problems. t has been shown that the excess air factor depends on the type of combustible fuel, the method of its combustion and the structure of the boiler combustion chamber. A construction of the closing mechanism of the combustion chamber of a solid fuel boiler is proposed. Based on experimental and computational research, a model of the boiler door handle was constructed, when automatic opening would be impossible. Such a design of the mechanism closing the combustion chamber of a solid fuel boiler allows to increase its efficiency as a result of the stability of the gas mixture composition and to reduce the risk of carbon monoxide falling into the room.

The work analytically investigates a new recuperative-transformer system with subcooling of the recirculation flow of furnace cooling, which increases the heat-technological and energy efficiency of furnace units, expanding the technical and economic efficiency of industrial heat supply. The basis of the research is the conclusion that the application of heat pump technologies for energy saving in the production of building materials in rotating furnaces with the utilization of low-temperature gas-air flows is very promising. It is noted that the stabilization of the thermal mode of furnace cooling during the year is an important technical and economic task aimed at improving the thermal process and energy saving, primarily for the firing zone. An analytical study of the recuperative transformer system with subcooling of the recirculation flow was conducted. The equation of the heat balance of the heat extraction system of the gas-air circuit in the process of furnace cooling is presented. The transfer of heat absorbed from the surface of the furnace in recuperative heat exchangers, as well as in the evaporator of the thermotransformer circuit of the vapor compression heat pump is described. A generalized dependence was obtained for the heat flow of furnace cooling and a low-potential source in the gas-air circulation circuit of the heat supply system. The dependence for the real conversion factor is determined. A graphical interpretation of the dependence of the effective conversion factor on the ratio of the consumption of the heating medium and the heated medium is presented. It is emphasized that the results of the study of the rational interrelationship of the initial and mode parameters create a basis for the engineering development of the proposed heat supply systems based on the stabilizing cooling of the rotating furnace. [ABSTRACT FROM AUTHOR]

It is found that the problem of boundary layer stability with a diffusion flame under the conditions of a constant molecular weight over the boundary layer in the inviscid approximation and in the Dunn–Lin approximation with identical Schmidt numbers can be reduced to a similar problem for a single-component gas. Approximately, this conclusion is also valid for different Schmidt numbers. Calculations of the steady-state parameters of the boundary layer show that there are two generalized inflection points testifying to a necessary condition of the "inviscid" Rayleigh instability. Simulations show that the boundary layer with a diffusion flame is most unstable to two-dimensional disturbances. As the frequency is increased, the phase velocity of the growing wave tends to the value at the generalized inflection point. Despite sufficiently large growth rates, the degree of spatial enhancement of the wave is equal with high accuracy to the ratio of the time degree of enhancement to the group velocity. [ABSTRACT FROM AUTHOR]

Observations of the Earth climate for the last 100−150 years have revealed that the atmospheric air temperature in the ground level shows quite a rapid growth. Megalopolises and other settlements behave as large sources producing thermal pollution of the Earth air basin. Transport facilities, heated buildings, and heat and electric networks release a significant amount of energy, which accumulates in the air medium of cities and then dissipates into the surrounding space. The most rapid change in the air temperature has been noted for the last 50 years. The greatest increase of the outdoor air temperature, e.g., in St. Petersburg, is observed in the cold period of the year. It has been determined that the average air temperature in the cold period of the year (from October to April) has increased by 1.51°С, whereas the average air temperature increased by 0.72°С for the same interval of time but in the warm period of the year (from May to September), i.e., half as much as in the cold period. It has been found from studies of regulatory and reference documents that the standard climatic data specified in them lag significantly from the currently occurring climate changes. The article presents an analysis of the outdoor air temperatures in St. Petersburg for the period from 1992 to 2021 and an assessment of air temperatures in the coldest day and the coldest 5-day spell with reliabilities of 0.92 and 0.98 and also the absolute minimal air temperature for the considered 30-year interval of time. It is pointed out that the actual climatic indicators derived from statistical processing of daily data arrays are by 3–4°С higher than those specified in the relevant standards. As a result, when buildings are designed for the standard conditions specified by the existing regulations, the contractual loads turn out to be overestimated essentially in comparison with the actual ones, which is revealed in designing the configurations of settlement heat-supply systems. The consideration of actual climatic indicators opens up the possibility to decrease the contractual heat loads of consumers on a sound basis and, as a consequence, to achieve thermal energy saving without degrading the heat-supply quality. [ABSTRACT FROM AUTHOR]

The article describes in detail the advantages of using heat pumps, such as increased energy efficiency, saving heating costs, and reducing emissions into the atmosphere. The principles of operation and application of electric discharge technologies for water treatment, ensuring its safety and purity, are also considered. Various schemes for integrating new technological solutions into existing heat supply systems are proposed in order to increase efficiency and reduce costs. Examples of successful implementation of these solutions in various cities and regions are given. The study shows that the modernization of heat supply systems using modern technologies can significantly improve the quality of customer service, reduce the burden on natural resources and make heating more environmentally friendly.