The development of methods for calculating the dynamics of the energy thermal characteristics of the accelerated hydration process is one of the most difficult tasks of heat power engineering. The article describes a new method of calculating the thermal characteristics of the process, focused on its application in the installations of accelerated hydration used for the production of 3D-reinforced concrete structures. The principles of cellular-automatic modeling of energy characteristics of concrete heat treatment process were used in the development of the method. The mathematical apparatus used in the method is based on the finite-difference three-dimensional heat equation, which allows taking into account, due to the system of boundary and initial conditions, the spatial dimensions of the concrete product, the spatial arrangement of the formwork, the spatial distribution of heating elements and other design features of the accelerated hydration system. The input parameters of the models used are the density, thermal conductivity, heat capacity of the concrete mixture and structural elements included in the tooling of the product. Boundary and initial conditions will make it possible to solve modeling problems for any 3D-design. The goal of the study is to develop a method for calculating the energy characteristics dynamics of the hardening of 3D-concrete products subjected to heat treatment, based on a grid non-equilibrium thermal model. The paper presents a mathematical equation apparatus that allows linking the geometric characteristics of the product and the finite-difference equations of thermal conductivity, including sources of heat. A numerical method for determining the energy characteristics of the hardening of 3D-concrete products subjected to heat treatment has been proposed consisting of, depending on the time of heat treatment, the calculation of the outside heat supplied to the concrete product, heat dissipated into the environment, the emitted heat of hydration and the heat accumulated in the concrete product during heat treatment, taking into account the geometry of the product. The method is based on a grid three-dimensional thermophysical model that takes into account the nonequilibrium and the system of boundary conditions that reflect the specifics of the process in the accelerated hydration of concrete. Calculations of the functions of the energy characteristics determining the heat treatment, depending on the time of heat treatment for cubic 3D-concrete products of different sizes have been performed. It is demonstrated that the rate of alteration of energy characteristics can be modeled for products of any spatial configuration.

The increase of average outdoor temperatures and their fluctuations over the past 20 years (as evidenced by the records of summer temperatures in our country) has significantly increased the need for air conditioning premises where people are present for a long time, especially when they are crowded (shops, entertainment halls, classrooms, etc.). The air conditioning process is quite energy-intensive, but the growth of well-being in many republics of the former USSR, as well as the increasing complexity of the physiological adaptation of the human body to rising outdoor temperatures make it possible (and at the same time necessary) to implement these systems on a large scale. It is important to take into account that electricity prices are currently maintained at a high level for homeowners, and in the coming years the prices will only grow. Therefore, the development of new ways of significant increase of the energy efficiency of the indoor air conditioning process is of a great interest. One of these methods is the use of laminar (or close to them) moving layers of conditioned air in a limited area of work or rest of people. Such a zone, about 1.0‒1.2 m height from a floor in each apartment is, e.g., living rooms (bedroom) in which standard temperature conditions are created by means of simple air supplying and air intake devices. In the case of sedentary work of people, the height of such a zone of conditioned air should be increased to 1.3‒1.5 m. It has already been established that the use of laminar (or close to them) air flows allows to reduce the power consumption by two or more times due to significantly reduced heat exchange with the surrounding heated surfaces. Besides, the simplicity of such systems ought to be noted. In particular, in conditions of modern systems of control and management of air conditioning, the "duties" of consumers include only the installation on the control device of the initial data relating directly to the required parameters of the microclimate. At the same time, it should be noted that there is currently no complete scientific and technical description of aerodynamic and heat exchange processes in the air conditioning zone. Even in modern conditions for countries with a sharply continental climate (Russia, Kazakhstan, etc.), the problem is the choice of the type of air conditioner for its effective use in hot periods of summer. In general, it can be noted that all the problems of energy-efficient use of air conditioners must find a comprehensive solution.

The article presents a new method for determining the composition of wood generator gas produced in gas generators of the inverted gasification process. The shortcomings of the existing calculation methods are analyzed, the main of which is the insufficient harmonization of the calculation results with the experimental data. The authors substantiate the priority of the main chemical reactions occurring during gasification of wood fuel. There are three active zones of gasification, viz.: a redox zone, a reduction zone and a zone of interaction of gasification products with each other and with the carbon of the fuel. In general, a redox zone consists of two subzones: in the first one reactions of water gas formation occur, and the second one appears when excess air is supplied to the gas generator. The proposed method for calculating the components of the generator gas is a set of a modified balance method and an added method for calculating the concentrations of chemical reaction products by the equilibrium constants of these reactions in the active gasification zones with different temperatures. The modified balance method considers the primary processes of wood and moist air transformation into components of the generator gas in the first subzone of the redox zone. The modified balance method is based on the equations of material balance of carbon, hydrogen, oxygen, moisture, nitrogen and thermal balance of the system. The added method determines the concentrations of the components of the generator gas in the second subzone of the redox zone, as well as in the reduction zone and the zone of interaction of the gasification products with each other and with the fuel carbon. The combination of these two methods makes it possible to calculate with greater accuracy the output of the generator gas, the concentration of its components, fuel and air consumption, as well as a number of other characteristics of the gas generator.

The features of economic diagnostics of power engineering enterprises in the Republic of Belarus are considered. Accounting and analysis of the activities of enterprises of the power system in the emerging energy market requires improving approaches of economic monitoring. This can be achieved through a comprehensive system of economic diagnostics of the enterprise. The structure of economic diagnostics is represented by three elements, viz.: rapid diagnostics, diagnostics of bankruptcy and complex diagnostics of the economic condition, each of which has its own purpose and objectives of the study, as well as its own content of the reports to be analyzed reporting and of analytical procedures to be fulfilled. The choice of methods of economic diagnostics also depends on the stage of the life cycle of the enterprise. But it is the specificity of the type of economic activity that has a major impact on the diagnosis. The article describes the specific features of using methods of express-diagnostics, diagnostics of bankruptcy based on multivariate models as well as of integrated diagnosis of power utilities (by example of “Oblenergo” enterprises). The study demonstrated that the use of universal financial ratios in rapid assessment and models for assessing the risk of bankruptcy for domestic energy enterprises is not quite suitable, since these methods do not take into account the existing specifics of the structure of the capital of the organizations of power engineering system. The authors came to the conclusion that each of the approaches to diagnosis makes it possible to evaluate only individual criteria of the state of the economy of the organization. To improve the efficiency of analytical work at the enterprises of the power system, it is necessary to improve diagnostic procedures taking into account the technological features of production and the influence of factors of the external and internal environment. Only a comprehensive diagnosis can give a comprehensive unbiased assessment of the enterprise at all stages of its life cycle.

Knowledge of the nature of the energy load alterations not only in time, but also in space will allow achieving the optimal structure of energy sources in the city and thereby reducing unproductive energy costs of energy resources and increasing energy efficiency. Changing the paradigm of power supply systems development towards the development of small distributed power production, intellectualization and demand management requires a more accurate understanding of the planned local loads in the city. At present it is still difficult to obtain such data; it requires analysis of many sources and, consequently, takes a lot of time. The article presents a possible algorithm of formation of the space-time profile of energy resources consumption. At the heart of the load disaggregation there is a spatial distribution of consumers in the city, estimated by the density of the distribution area of buildings of energy consumer groups. The dimension of the model is not limited in both temporal and spatial resolution: the model is flexible and can be adapted to different cases and local conditions. The proposed algorithm has been applied to the modeling of the profile of electricity consumption in St. Petersburg. The profile is based on an annual graph of electricity consumption by hour (8760 values). The spatial resolution of the model ranges from hundreds of meters to several kilometers and depends only on the availability of initial data. In the example, the division of the city territory into administrative districts (18 districts of St. Petersburg) is used as a spatial unit. The obtained results showed their logicality and compliance with empirical observations.

The energy sector of the Republic of Belarus is one of the key sectors of the national economy, the effective development of which ensures the operation of the entire real economy and the sphere of housing and communal services. Due to the lack of the necessary amount of its own energy resources, the country is affected by factors of internal and external threats that form the energy dependence of the Republic on the supply of fuel and energy resources from outside. This weakens its energy security. The main importing country of fuel and energy resources for the Republic of Belarus is the Russian Federation. In this regard, the concept of energy security needs to be clarified, taking into account external and internal threats. The article deals with theoretical approaches to the definition of energy security, the specific features for the importing and exporting countries. The main threats to energy security for the Republic of Belarus are clarified, the causes of their occurrence and consequences for both fuel and energy complex enterprises and energy consumers are revealed. To determine the level of energy security, the indicative assessment method, which involves the identification of parameters and indicators of the development and functioning of the fuel and energy complex, its subsystems and facilities, as well as energy consumers, is the most optimal. These parameters characterize the composition, depth and territorial framework for the implementation of threats to energy security, its level. The indicators of the main directions of energy safety have been analyzed in dynamics; their levels are determined by periods. The directions of energy security, which are most and least susceptible to threats, have been identified. A combined approach for determining the objects of energy security is proposed. The author's definition of energy security is presented.