Efficiency Of Heat Supply Systems Research Articles

Analysis of thermotechnical characteristics of the thermoelectric film heating system

Modern world trends in increasing the energy efficiency of heat supply systems, in particular, are aimed at decentralizing the supply of heat to consumers, and also involve the use of low-temperature heating systems. The Institute of Technical Thermophysics of the National Academy of Sciences of Ukraine together with the specialists of the Department of Thermal and Alternative Energy of the National Technical University of Ukraine “Ihor Sikorskyi Kyiv Polytechnic Institute” carried out scientific research and analysis of the main thermal characteristics of the electrothermal film heating system (model ZHDM-WM-220-180 /225/270) and accessories for it manufactured by ZHONGHUI (HEILONGJIANG) UNDERGROUND HEATING CORPORATION (People's Republic of China). The results of the study of the main thermal technical characteristics of the thermoelectrical film heating system are given. The analysis of the design of the heat-dissipating mat showed relatively high reliability of its components and acceptable operational characteristics for various objects of the housing and communal economy.

Повышение энергетической эффективности работы тепловых сетей за счет утилизации тепловых потерь

The efficiency of thermal energy transfer, which is inevitably accompanied by heat losses through the insulation of pipelines, directly characterizes heating networks and centralized heat supply systems in general. The most important task in terms of current approaches to energy efficiency is to improve the efficiency of thermal energy transfer in modern heat supply systems. Currently known technical solutions to reduce heat losses through insulation of pipelines reduce heat losses, but not significantly. So, the purpose of this study is to develop a technical solution to reduce (even eliminate) standardized linear heat losses in heat supply networks of industrial enterprises. The authors have used methods of experimental research of heat transfer processes and mathematical modeling of heat and power equipment. A device for recycling heat losses is proposed. It is designed to reduce (even eliminate) normalized linear heat losses in heat supply networks of industrial enterprises. The permissible heat absorption of the device collector is determined, and a method for its regulation is described. An engineering method for calculation of the proposed device has been developed. The effectiveness of application of heat-reflecting screens in heating networks has been determined. A number of problems have been solved to improve the efficiency of heat supply systems of industrial enterprises using a device for recycling heat losses in the heating system channel.

Assessment of the energy efficiency of heat supply systems in the arctic zone of Russia

One of the main tasks of recent years is the development of the Arctic region of Russia. This is due to the economic, political and defense interests of the country. The Arctic zone is characterized by harsh climatic conditions and, as a consequence, high consumption of energy resources to ensure uninterrupted operation of heat supply systems. Taking into account the fact that fuel oil, supplied from other regions, is used as the main type of fuel, the issue of energy efficiency of heat supply systems is quite acute. The proposed methodology for assessing energy efficiency is based on several mathematical methods, including the method of correlation analysis, the method of ranking of indicators and the method of expert criterion evaluation. Generalization of these methods as applied to the heat supply system allowed to create a methodology of criteria assessment of energy efficiency of heat supply systems, allowing with minimal time and with high accuracy to evaluate the effectiveness of the entire system and its individual components. In addition, the application of criteria assessment makes it possible to determine the most relevant areas of energy saving of heat supply systems and to assess the technical and economic effect from the implementation of a particular energy saving measure, taking into account a wide range of external factors and the characteristics of specific heat supply systems.

Development of an Information Model of a Heat Supply System at Various Stages of the Life Cycle

Introduction. Data on elements of heat supply systems of the Russian Federation (heat sources, heating networks) are given as well as the main energy characteristics. The main problems in the industry are indicated. It is concluded that it is necessary to optimize the operation of heat supply systems in all its links and at all stages of the life cycle.Materials and Methods. For optimal control of thermal power systems, the authors consider it expedient to create a digital information model of each element of the system at each stage of the life cycle, including: - three-dimensional engineering digital terrain model; - three-dimensional engineering digital model of heating networks, taking into account adjacent communications and structures;- operational digital model of the heat supply system on the platform of the geoinformation software complex Zulu21. The technology of data exchange in IFC format between software complexes is given. The necessity of verification of the operational model using the data of field measurements on the physical model of the heat supply system is indicated.Results. The creation of a digital information 6D model of the heat supply system allows you to move to a higher level: intelligent dynamic control of a complex energy system (neurocontrol). The SCADA software package in online mode collects the necessary information (temperature, pressure, coolant flow) from sensors installed at characteristic points of the system. All information is transmitted to Zulu, a software package with built-in support for OPC technology to receive data from a SCADA system. The received data is fed into the ZuluGis software package, which includes the ZuluThermo module, with a loaded digital information model of the heat supply system. The actual thermal and hydraulic modes of the system are calculated in the module. Data on the optimal and actual thermal-hydraulic modes are transmitted to the neurofeedback unit for comparison and management decisionmaking. The decision is transmitted to the appropriate controller to initialize actions to change a parameter.Discussion and Conclusions. A technology for developing a digital information model for elements of a heat supply system at all stages of its life cycle is proposed. The creation of a digital information 6D model of the heat supply system allows you to move to a higher level: intelligent dynamic control of a complex energy system (neurocontrol). The use of intelligent control makes it possible to improve the quality of decisions made, significantly increase the energy efficiency of heat supply systems and the quality of services provided to the end user.

Perspective Ways of Energy-Efficient Modernization of Heat Supply Systems Based on Heat Pump Technologies

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 decentralized 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 reconstruction of heat supply systems and the establishment of a generalized indicator of the conditions for increasing the efficiency of using primary fuel energy. This made it possible to formulate 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 district 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 primary fuel with its savings of 1-2.7 times.

Increasing energy efficiency of heat supply systems of facilities using non-traditional sources

Increasing energy efficiency of heat supply systems of facilities using non-traditional sources

Development of low-pressure electric steam heater

The study was devoted to solving the issue of creating new electric heating devices that can be used in autonomous heat supply systems. The issues were resolved by developing an original low-pressure electric steam heater. The study was aimed at improving the efficiency of heat supply systems for buildings and structures. Given the current trends in the global striving for energy conservation, it cannot be fully realized without the introduction of high-tech and low-energy-consuming electrical equipment. As a result of theoretical studies of a heat pipe with an electric heater, a design of an electrovacuum heating element has been developed. The low-pressure electric steam heater can be used in heat supply systems of autonomous users. Thermal energy transfer is currently accompanied by substantial energy losses since the heat carrier has to pass considerable distances. Switching of the facility to the heating plant is impossible in some cases because of technical problems or significant material costs for laying pipelines. As a result of the study, the dependence of heating the heat pipe at various volumes of the heat carrier and mass of the pipe itself was established. When a certain mass is reached, the temperature of the heating surfaces can reach 70 °C which is considered acceptable. The experimental data obtained have made it possible to develop an electric heater of new generation with a fundamentally new design of the heating element. It combines the efficiency of an electric spiral and comfortable warmth from a traditional radiator. This heater is an explosion and fire-safe and can be integrated into the Smart Home system

Improving the efficiency of heat supply systems for infrastructure facilities by optimizing the pipeline subsystem according to technical and economic indicators

The fuel economy, which provides acceptance, storage, preparation and supply of the necessary amount of fuel oil for its combustion in boiler furnaces, is one of the energy-intensive technological subsystems of thermal power plants and boiler houses. The design of new technological pipelines and the modernization of existing pipeline systems for transporting fuel oil involves hydraulic calculations. Generally accepted in practice is the hydraulic calculation of pipeline lines based on the flow continuity equation and the Bernoulli equation for a real viscous liquid, which takes into account the pressure loss due to friction and to overcome local pipeline resistances. With this approach, hydraulic calculation is a multi-variant task, since there are an infinite number of combinations of parameters pipeline diameter - pressure drop, which are not equal from both economic and technical points of view. Research of literature sources has shown the feasibility of conducting hydraulic calculation of pipe-wire lines on technical and economic indicators. As a criterion for optimization of technological pipelines, the total annual costs for the creation and operation of the pipeline, which are a linear superposition of capital and operational costs, are proposed. The paper offers calculation relations for determining the optimal diameter of the pipeline from the condition of minimum total annual costs for its creation and operation, taking into account current prices and tariffs for the pipeline and electricity, pipeline tracing, conditions of its operation, as well as the properties of the transported medium. On the example of a hydraulic installation for pumping fuel oil, computational experiments were performed to assess the influence of the pipeline diameter on its technical and economic indicators and determine the optimal parameters of the fuel oil pipeline.

Energy efficient optimization of heat supply system for oil therminal

In the context of the need to develop the transport infrastructure of Ukraine and to diversify sources of energy carriers supply to the country, including oil and oil products, the problem of the development of oil terminals arises. This work is devoted to the optimization of the structure of heat supply to oil terminals. In this sense it is relevant. The object of research is the heat supply systems of an oil terminal. At the same time, the subject of research is the energy efficiency of heat supply systems for oil terminals using water vapor and high-temperature organic heat carriers. The following research methods were used: an analytical review of information sources, a technical and economic analysis with the necessary substantiating calculations. As a result of the studies, the possibility of using high-temperature organic heat carriers for organizing heat supply to oil terminals has been shown. The advantage in the efficiency, environmental friendliness and reliability of systems with high-temperature organic heat carriers versus systems using water vapor as a heat carrier is shown. On-site heating networks in the oil terminal are recommended. The main advantages are that the heat losses in them have been reduced and the reliability of the system has increased. The cost estimation of capital investments of the compared variants of the heat supply system arrangement is carried out. The centralized heat supply systems have greater equipment cost compared with the decentralized ones. The operating cost for decentralized systems is also lower due to a decrease in specific fuel and electricity consumption. The materials obtained as a result of the research can be used as recommendations for the design of heat supply systems for oil terminals using high-temperature organic heat carriers.

Smart Asset Management for District Heating Systems in the Baltic Sea Region

The purpose of this review is to provide insight and a comparison of the current status of district heating (DH) systems for selected Baltic Sea countries (Denmark, Germany, Finland, Latvia, Lithuania, Poland, and Sweden), especially from viewpoints of application and solutions of novel smart asset management (SAM) approaches. Furthermore, this paper considers European projects ongoing from 2016, involving participants from the Baltic Sea Region, concerning various aspects of DH systems. The review presents the energy sources with particular attention to renewable energy sources (RES), district heating generations, and the exploitation problems of DH systems. The essential point is a comparison of traditional maintenance systems versus SAM solutions for optimal design, operating conditions, and controlling of the DH networks. The main conclusions regarding DH systems in Baltic Sea countries are commitment towards a transition to 4th generation DH, raising the quality and efficiency of heat supply systems, and simultaneously minimizing the costs. The overall trends show that applied technologies aim to increase the share of renewable energy sources and reduce greenhouse gas emissions. Furthermore, examples presented in this review underline the importance of the implementation of a smart asset management concept to modern DH systems.

Creating an environmentally safe and reliable heat supply system through the introduction of energy-saving technologies in housing and common utilities services

The rational use of natural resources and the creation of an environmentally safety is a priority goal for all mankind. The increasing pollution of the atmospheric air by the combustion products of various types of fuel actualizes the problem of improving the environmental safety and efficiency of heat supply systems (HSS). Heating is the most energy intensive and wasteful sector of the national economy, because the turnover is comparable to 2.1% of GDP and an average of 50% in payment of citizens for housing and communal utility services (HCUS). However, HSS today is in a critical state at all stages of production, distribution and consumption of heat, which is especially typical for HCUS enterprises in Russia. Accordingly, the population is not satisfied with the quality and price of HCUS services. The purpose of the study was to develop a mechanism for creating an environmentally safe and reliable HSS by introducing energy-saving technologies that can improve the quality and reduce the price of HCUS services. The data analysis of the online survey of Russians in social networks in 2018-2019 is carried out. The average level of the population satisfaction with the quality of the provided services of HSS is determined.

Развитие теплофикации в России: отечественная научная база

Relevance. The development of a scientific base in the field of thermal energy is inextricably linked with cen-tralized heat supply and its progressive direction of heating. Centralized heat production remains the main focus of improving the efficiency of heat supply systems. The scientific base, created in the Soviet period, confirmed the cor-rectness of the scientific and engineering decisions taken during its creation, made it possible to accumulate experience for improving the thermal power industry. The purpose of the study is to identify the facts of the development and practical activities of the domestic scientific base in the field of thermal energy during the years of Soviet power. The objective of the study is to analyze the features of the work of scientific institutes in the field of the devel-opment of domestic district heating at various stages of formation. Methodology. In the course of the analysis of various scientific sources, various methods were used: problem-chronological, historical, comparative methods. Thus, the choice of the historical method is applied due to the study of the dynamics of the development of the domestic science of thermal energy. Results. In the course of studying and generalizing various literary and archival sources, the study proved the fact that domestic scientific institutions have developed intensively and over the years have reached significant proportions, which have determined the development of modern thermal energy. Conclusions: In the process of studying various literary and archival sources, it can be concluded that the do-mestic scientific base in the Soviet years allowed for the perfect supply of heat energy to industrial and residential buildings of the Soviet state. These facts can contribute to the development of a strategy for improving modern domestic thermal power engineering.

Selection of the structure of thermal generation in cities of the russian federation when actualizing the heat supply schemes

THE PURPOSE. To analyze the materials of heat supply schemes for large cities of Russia, to consider the impact of an increase in the number of boiler houses in cities when planning the development and modernization of heat supply sources. To develop a methodology for choosing the structure of thermal generation in cities, which is distinguished by the use of an additional criterion for energy efficiency and a system of taken into account restrictions on the energy balances of the region. The weakening of attention to the overall energy efficiency of the aggregates of heat generation sources is shown, an additional reserve for increasing the energy efficiency of heat supply of cities is identified. METHODS. When solving this problem, methods of comparative analysis of the heat supply schemes of large cities of the Russian Federation over the past 7-10 years is used. RESULTS. The article describes the relevance of the topic, created a methodological base aimed at increasing the energy efficiency of heat supply systems in the city. A criterion is proposed that takes into account the different efficiency of sources and structural effects that are realized when choosing the composition of working heat sources for the prospective of urban development. The basic provisions, the relations used, the features of the developed methodology are given. A conclusion is drawn on the appropriateness and effectiveness of these proposals when testing this method. CONCLUSION. The developed method for choosing the structure of thermal generation was tested in the analysis of schemes of large cities of the Russian Federation. Efficiency on the example of the districts of Nizhny Novgorod ranged from 16.5 million to 180.0 million rubles per year.

Reliability and efficiency of heat supply systems in the Leningrad region

Currently, Russian heat supply system is at the stage of not just organizational, but also technological changes. Any decisions are based on determining priority criteria.The goal of our research is to develop a set of organizational and technical solutions improving the efficiency of production and supply of heat to end consumers, taking into account the criterion that will be defined as the main one for a particular system. Current feasibility of the “generation” subsystem depends on the condition of its main generating equipment, the degree of its load, as well as the efficiency of the distribution of heat load between sources; “transportation” depends on the state of heat supply grids and the extent of their load; “consumption” depends on the state of thermal protection of buildings, losses of consumers, as well as the degree of automation of district heating substations.The criteria may be:1. Minimum time for the renewal of fixed assets: important in the conditions of disruption of the quality of heat supply. However, research did not confirm any significant violations[1]2. Minimum variable costs: impact on the formation of tariffs for the population and the price for the industrial consumer;3. Minimum grid transmission losses: for most systems, they are determined by regulations, not by actual measurements on heat supply grid sites. Not only the radius of effective heat supply and revised production technologies are important, but also the location of facilities and their capacity. However, confirmation of this version calls for implementation of a system for monitoring the state of heat supply grids, for example, based on optical fiber. This can lead to the development of distributed heat energy industry at the level of house heating substations;4. Economic and budgetary efficiency, taking into account different project financing solutions.

The use of porous metals in heat exchangers

Heat exchangers are widely used in heat supply systems. To increase the efficiency of heat supply systems, heat exchangers with porous metals are proposed to design. There was a test facility set up to study new types of heat exchangers. The countercurrent flow of heat carriers was activated in those heat exchangers. Freon moved through the heat exchanger pores, and water moved through the inner tubes. It should be noted that the porous materials in the heat exchangers differed in the coefficient of porosity. To be compared, one of the heat exchangers did not contain any porous material. The first test cycle proved the feasibility of using porous metals in heat exchange equipment. Afterwards, a simplified mathematical model of the heat exchanger was compiled. Such an analytical form makes a solution convenient for engineering calculations. Numerical calculations based on this model were compared with the experimental data. Heat transfer intensity of materials with different porosity was compared. This method can be applied in case when the heat exchange surface area is unknown. Moreover, it takes into account the heat capacity and heat of the phase transition of freon, if any.

The use of porous metals in the design of heat exchangers to increase the intensity of heat exchange

Heat exchangers are widely used in heat supply systems. To increase the efficiency of heat supply systems, heat exchangers with porous metals are proposed to design. There was a test facility set up to study new types of heat exchangers. The countercurrent flow of heat carriers was activated in those heat exchangers. Freon moved through the heat exchanger pores, and water moved through the inner tubes. It should be noted that the porous materials in the heat exchangers differed in the coefficient of porosity. To be compared, one of the heat exchangers did not contain any porous material. The first test cycle proved the feasibility of using porous metals in heat exchange equipment. Afterwards, a simplified mathematical model of the heat exchanger was compiled. Such an analytical form makes a solution convenient for engineering calculations. Numerical calculations based on this model were compared with the experimental data. Heat transfer intensity of materials with different porosity was compared.

A Mathematical Model for Optimal Number of Heat Consumers Connection to the Heat Supply System

In the modern world, the efficient use of energy is an extremely important aspect of human activity. In particular, heat supply systems have significant economic, environmental and social importance for both heat consumers and heat supply organizations. The economic status of all participants in the heat supply process depends on the efficiency of the functioning of the heat supply-systems. The reliability of the functioning of systems depends on vital processes such as the work of hospitals and industrial enterprises. With such a close network communication, reliable and efficient operation of power supply systems is critical. In this article, ways to improve the efficiency of heat supply systems are considered. A mathematical model for improved planning of heat supply systems by connecting the optimal set of new heat consumers is presented. For each single customer, when there is an alternative option for connecting this consumer to the existing heat network, it is possible to choose the only optimal solution. This becomes possible due to the restrictions and the procedure for selecting variants from a subset of binary variables corresponding to alternatives. The procedure for finding the optimal number of consumers for connection to the existing heat network is presented, which is the rationale for increasing the number of existing consumers of the heat network. The testing was carried out and the results of the mathematical model by an example of test heat networks are presented. Directions of further study of increasing the efficiency of heat supply systems and integrating the presented mathematical model with modern software complexes are determined.

Study of factors affecting reliability and efficiency of heat supply system

Reliable and uninterrupted supply of heat to consumers is the most important task of the heating system. Due to the connection to the heat network of a large number of dissimilar consumers, the heat supply system operates year-round. Damage to heat networks can lead to disconnection of consumers, disruption of internal engineering systems, and reduction of their operation parameters, which can be dangerous, especially during the heating period at low outdoor temperatures. To ensure the reliability and efficiency of the heat supply system, it is necessary to fulfill all the requirements of the technical operation rules, conduct timely rounds and inspections and identify damage to the heating network at an early stage. It is also necessary to identify factors affecting the reliability and, consequently, the efficiency of the heating system, identifying “risk zones” by the magnitude of damage, based on the results of the calculation. As well as the development of measures to identify and prevent failures in the heating system.

Electrovacuum heating elements

Improving the efficiency of heat supply systems for buildings and structures in the current trends in the global development of energy saving cannot be fully realized without the introduction of high-tech and low-energyintensive electrical equipment. The heat supply of remote objects for various purposes is accompanied by significant losses, since the coolant has to cover considerable distances, in some cases the connection of the object to the heating plant is impossible due to technical problems or considerable material costs for the installation of pipelines. One solution could be the introduction of a low-pressure steam electric heater. This is a new generation electric heater with a fundamentally new design of the heating element. It combines the efficiency of an electric spiral and the comfortable warmth of a traditional heating radiator.

REDUCTION OF NATURAL GAS CONSUMPTION AND REDUCTION OF EMISSIONS WITH COMBUSTION PRODUCTS IN MUNICIPAL HEAT SUPPLY

The technical solutions are proposed to reduce the consumption of natural gas, as well as to reduce emissions with combustion products in the municipal heat supply systems:
 - New constructions of water-tube and water-fire-tube boilers with improved technical, economic and environmental characteristics have been developed. Replacing of old boilers with these boilers within Ukraine will provide an economic effect of about 100 thousand tons of fuel equivalent per year. NOx reduction will be up to 35%;
 - The new temperature mode for heating networks 115/70 oС has been developed, which provides the amount of heat that is adequate to the needs of consumers, and is appropriate for use in cities of the country from an economic point of view. However, the implementation of such reduced temperature mode requires a corresponding change in the general requirements when issuing "Technical Specifications" for connection to district heating systems, necessitates changes in the temperature mode values in other documents, for example the general plan of the city, as well as the possible need to change the calculated heat loads in concluded contracts for heat supply to consumers. Nevertheless, the correction of temperature modes of cities should be considered as one of the possible measures to improve the energy efficiency of heat supply systems;
 - The expediency of partial replacement of natural gas in the municipal heat supply systems of large cities of Ukraine with municipal solid waste (MSW) has been proved. The ways of improving the efficiency of mixed MSW combustion in conditions of country, including the extraction of "wet" biowaste from the total mass of mixed MSW with using a separate collection. are determined;
 - To achieve compliance with the new more stringent European environmental standards, the highly efficient devices for cleaning combustion products from particulate matter and sulfur oxides have been developed. The efficiency of dust removal in centrifugal filters is 90...98%, in cyclone dust collectors - 90...93%. Desulfurization efficiency is up to 50%.