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编号 1 (2025)
Articles
Determination of efficiency and reliability criteria for the actual district heating system and proposals for the development of a distributed heating supply area based on prosumer
摘要
The paper presents the main results of practical application of the developed methodology for efficient expansion of district heating systems. The methodology at issue involves determining the efficiency areas of district heating, assessing technically and economically the implementation of distributed heating sources of prosumers at the boundaries of effective heat supply radius; analyzing and ensuring the reliability of heating to consumers in the district-distributed area of the system.
3-12
Design of integrated energy systems based on their digital twins
摘要
Design of integrated energy system (IES) is a complex problem, which is caused by the complex network configuration of these systems, a wide range of used equipment and mathematical models of IES subsystems. The digital twin allows one to model in virtual space various configurations of IES and to obtain the optimal variant of construction of the system under study. The paper proposes the principles of digital twin for design of IES. The authors present a methodological approach to the design of IES on the basis of its digital twin. The results of modelling of the energy supply system obtained on the software implementation of the components of the digital twin of the IES are presented.
13-30
Investigation of the effective thermal conductivity of materials based on triply periodic minimal surfaces of the Diamond, Gyroid, and Fisher–Koch S types
摘要
The article investigates the thermal conductivity properties of lattices based on the topology of triply periodic minimal surfaces (TPMS) such as Gyroid, Diamond, and Fisher–Koch S. Using numerical and experimental methods, empirical relationships were established between the effective thermal conductivity of these structures and their geometric parameters as well as the properties of the base material. The derived relationship allows for the creation of materials with specified thermal conductivity characteristics. The advantages and disadvantages of TPMS structures for implementation as fins in heat exchange devices were identified. The Fisher–Koch S structure can be considered for use as heat exchanger fins, as it demonstrates the highest surface area, effective thermal conductivity, and minimal stagnant zones among the TPMS considered. With equal surface period and lattice thickness, the Fisher–Koch S structure shows 39% higher thermal conductivity compared to Diamond and 96% higher compared to Gyroid.
31-47
Integral model for the long-lived radioactive waste disposal using the “self-immersion” method
摘要
The presented integral model of radioactive waste disposal using the method of heat-generating capsule self-immersing into geologic rocks includes three stages: the stage of heating and the beginning of melting of the rock surrounding motionless capsule, the stage of quasi-stationary movement of the capsule, and the stage of the capsule deceleration. It is shown that as a result of capsule immersion into the melting rock the focusing of heat flow takes place, so that the capsule moving continues even at the heat rates significantly less than the critical value required for the start of melting. A possible radioactive waste composition and the immersion depth depending on burial environment were analyzed.
48-60
Basic model of heat transfer process in a radiation-transparent solid body with absorbing spherical layer
摘要
Theoretical studies on the problem of laser initiation of explosive decomposition in heterogeneous energetic materials place significant importance on the mathematical model of the heat transfer process in an isotropic solid body containing an absorbing inclusion in the form of a spherical layer. Difficulties are known to arise when seeking an analytical solution to the corresponding problem of non-stationary heat conduction, both through the application of Laplace’s integral transformation with respect to the time variable and singular integral transformation with respect to the spatial variable. This explains the absence of an analytical solution for the considered problem using current methods.
The task of determining the temperature field in an isotropic solid body with an absorbing penetrating radiation inclusion in the form of a spherical layer is formulated. The implemented mathematical model of the heat transfer process represents a mixed problem for a system of three second-order partial differential equations of the parabolic type in the presence of a non-stationary heat source in the system. An analytical method for solving the problem is proposed, which consists of two main stages.
The first stage involves finding the solution to the problem in the space of the Laplace integral transformation image, followed by its asymptotic expansion. The procedure used allows for the estimation of the extent and radius of the boundary of the thermal disturbance zone for large values of the Fourier number. The second stage, based on the application of the developed finite integral transformation with respect to the spatial variable for a three-layer region, completes the procedure of constructing an analytically closed solution to the original problem of non-stationary heat conduction.
61-75
Unsteady thermal conductivity of a hollow spherical body
摘要
Analytical solutions to various problems of thermal conductivity are presented, as a rule, in the form of infinite series and require knowledge of the roots of the characteristic equation, for the determination of which numerical methods are currently used. In this article, the problem of unsteady thermal conductivity of a hollow spherical body and an analytical method for solving a characteristic equation for boundary conditions of the second kind are considered. Simple algebraic expressions for determining the eigenvalues of the characteristic equation are proposed. Earlier in the works of the authors [6, 7, 8], analytical methods for solving characteristic equations for flat bodies (single-layer and multi-layer) under various boundary conditions were considered. This article is a further development of analytical methods for determining the roots of characteristic equations.
76-83
Long-term projections of electricity demand during the transition to carbon neutrality
摘要
The study discusses projections of electricity demand in the context of decarbonization of the Russian economy. We analyze the current state, long-term trends, and new applications of electricity and low-carbon technologies in major sectors of the economy. The study relies on a set of interrelated optimization, simulation, and input-output models as its methodological backbone. Each of the models serves its specific purpose and is tailored to a specific level of data aggregation. We report our projections of the dynamics of electricity demand for one of the scenarios of economic development to 2050 under decarbonization of the Russian economy. The study also provides estimates of extra demand for electricity resulting from intensive electrification of industrial and household processes, as well as electric transport development. We provide estimates of the possible impact of carbon tax on the prospective mix of power plants.
84-98