Pilot projects to improve the efficiency of the heating system. Improving the efficiency of heating systems. Autonomous power plants. Apartment ventilation systems with plate heat exchanger
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heating network hydraulic boiler
INTRODUCTION
1. LITERATURE REVIEW
1.1 Keyword Literature Review
1.1.1 Optimization of pipeline diameters
1.1.2 Evaluation of the efficiency of heat supply systems
1.1.3 Thermal management
1.1.4 Optimization and adjustment of operating modes of heat networks
1.1.5 Regulation of the hydraulic regime of the heating network
1.1.6 Pucking of heating networks
1.1.7 Basic provisions for setting up heat networks
1.1.8 Reliability of heat supply
1.1.9 Modern thermal insulation materials for heating networks
1.2 Conclusions and clarifications of the problem statement
2. DESCRIPTION OF ANALOGUES OF METHODS AND DEVICES
2.1 Analogues of dissertations
2.1.1 Improving the efficiency of the technology for replacing a defective section of the main pipeline
2.1.2 Optimization of thermal protection of pipelines and equipment of heating networks
2.1.3 Monitoring the reliability of heat networks
2.1.4 Improving the efficiency of district heating systems by optimizing thermal-hydraulic modes
2.2 Overview of patents
2.3 The main disadvantages of heating networks
2.4 Advantages of diameter adjustment
3. TECHNICAL SUGGESTIONS
3.1 Method for adjusting the hydraulic regime of the water heating network
3.2 How to adjust hot water systems
4. ECONOMIC SUBSTANTIATION OF THE THEsis
4.1 Calculation of technical efficiency
4.2 Calculation of economic efficiency
4.3 Calculation of economic effect
5. LIFE SAFETY DURING INSTALLATION OF HEAT NETWORKS
5.1 General
5.2 General requirements for work permit
5.3 General requirements for the organization of production areas
5.4 Safety requirements for storing materials
5.5 Fire safety
5.6 Ensuring safety during work
6. ECOLOGICAL SECTION OF THE THEsis
6.1 Ecology of boiler heating
CONCLUSION
LIST OF SOURCES USED
INTRODUCTION
In Russia, the main square, which is located in a harsh climatic region, is of great importance for providing consumers with thermal energy. Therefore, a centralized heating system is widely developed in our country, which allows creating comfortable living conditions with a significant reduction in fuel costs. When the operating cost also decreases.
Heating network are one of the most important and technically complex elements of the pipeline system in the municipal economy and industry. The high operating temperature and pressure of the heat carrier - water - is the reason for the increased requirements for the reliability of heat supply networks and the safety of their operation.
Currently, traditional methods and materials are used in their construction and repair, which leads to the need for a major overhaul every 10-15 years with a complete replacement of pipes and thermal insulation, as well as losses of up to 25% of the transported heat. In addition, you need to constantly carry out preventive work. All this requires expensive materials. Money. Every 10-15 years, a major overhaul with a complete replacement of pipes and thermal insulation, as well as losses of up to 25% of the transported heat. In addition, you need to constantly carry out preventive work. All this requires expensive materials and cash. .
To date, one of the promising areas in the energy sector is energy conservation.
The way to improve the efficiency of the energy sector is the introduction of programs and measures that make it possible to obtain high-quality, uninterrupted, cheap supply of heat and hot water to consumers.
Thermal networks consist of the following structural elements:
Pipeline;
Movable guides and fixed supports;
Compensator;
Shut-off and control valves.
The purpose of this dissertation is to increase the efficiency of heating networks by reducing the diameters of the supply and return pipelines.
In this dissertation work, a literature review was carried out by keywords, a review of patents and scientific journals, analogues of dissertations were selected and their description was made, as well as the main advantages and disadvantages were highlighted. Technical solutions for adjusting the hydraulic regime of heating networks are presented, the calculation of technical and economic efficiency is carried out, as well as the economic effect is calculated, the general provisions and requirements for life safety during the installation of heating networks, the ecological section of the dissertation work was completed and conclusions were drawn for all sections.
A presentation has been prepared, which reflects the topic and objectives of the dissertation work.
1 . REVIEWLITERATURE
1.1 ReviewliteratureBykeywords
1.1.1 Optimizationdiameterspipelines
A significant share in heat networks is made up of dilapidated, exhausted pipelines with large heat losses that require re-laying. The consequence of this is increased heat output from thermal stations and boiler houses and, accordingly, fuel consumption increases.
To reduce heat losses and in order to reduce fuel consumption, dilapidated heat pipes are being replaced. In many sections of heating networks, pipelines are laid with a diameter larger than necessary for the speed and flow of the coolant to ensure the load, therefore, simultaneously with the replacement, the diameters of the pipelines are being revised downward. .
To solve this problem, it is impossible to use any one method; a whole range of measures must be carried out, developed based on the results of thorough examinations of existing systems.
As a rule, before laying pipes are carried out:
Engineering diagnostics of the corrosion state of thermal networks;
Overhaul of exhausted heating networks;
Organization of a dispatcher control system for coolant parameters;
Reducing the temperature of the coolant in networks to optimal values;
Correction of operational temperature conditions.
Among other methods, this complex must necessarily include the optimization of the diameter of the pipes used.
In many sections of heat mains, pipes with a diameter larger than actually required in terms of the speed and flow rate of the heat carrier are laid to provide the attached heat load. The use of pipes produced according to new technologies leads to a reduction in heat losses in networks not only to the values determined by regulatory documents, but also to an even greater reduction due to a smaller diameter.
In addition to the main task, the problem of the cost of overhauling such pipes is also solved, emissions into the atmosphere are reduced and the reliability of the heat supply system is increased.
The problem of optimizing the diameter of the pipes used can be solved using existing software packages that include a complete set of functional components and their corresponding database information structures necessary for hydraulic calculation and modeling of heat networks.
Short pipelines with non-alloy steel pipes are most often calculated on the basis of available experimental data. The diameter of pipes for long pipelines or high-pressure pipelines with alloy steel pipes is determined by calculating economic parameters. When making an accurate calculation, it is important to consider how long the pipeline will operate and how constant the transported flow will be over different periods of time. Based on this, main pipelines are designed taking into account the average service life and the expected increase in the volume of transported material. When designing the pipelines of thermal power plants, on the contrary, the fact is taken into account that after several years of operation in full load mode, the number of hours of operation of the station per year will noticeably decrease. Considering these facts, it is recommended to design main pipelines slightly larger than the calculated dimensions, and pipelines of thermal power plants as accurately as possible according to the calculated dimensions.
The clear diameter of the pipeline, if the allowable pressure drop in the pipeline is set, is calculated using special formulas, taking into account the flow velocity typical for this type of pipeline and the transported medium. The calculation determines whether or not the pressure drop is within the allowable limits. .
The upper speed limit in all media applies to high-pressure pipelines, which are designed small for economic reasons.
If the dependence "flow rate - pipeline size" is incorrectly calculated, the pipelines become clogged. Erosion phenomena are observed in the pipelines for the water supplying the boilers with the salt to be removed, when the flow velocity exceeds about 8-10 m/s, when a certain limiting velocity is passed in gas pipelines and steam pipelines, the noise from the outflowing flow becomes too annoying. Particular attention should be paid to calculating the diameter of pipelines with domestic water, where deposits often form. With very hard water, even moderate heating can lead to significant clogging of the pipes. A similar effect is produced by reactions that are not always eliminated in pipes supplied to calciners. .
Implementation effect:
Reduction of heat losses in networks to the values determined by regulatory documents;
Reducing fuel consumption and tariffs for the population, improving the quality and reliability of heat supply.
The maximum efficiency from the implementation of the measure under consideration can be observed when the pipelines of heating networks are laid without channels using modern thermal insulation materials type polyurethane foam. Since at present in many regions of Russia there is a policy of implementing pipeline relocations in PPU insulation, the implementation, together with the relocations of the event in question, is relevant for any heat supply system. .
At present, the mass application of optimization of pipeline diameters during re-laying is not carried out for two reasons:
Lack of awareness;
Insufficient financing of work on the overhaul of heating networks (budget funds in many regions are allocated no more than for current repairs and the purchase of fuel).
When identifying the possibility of reducing the diameters of pipelines, the increase in the connected loads in the future and the effect of reducing the diameters on pressure drops at consumers should be taken into account.
The implementation of measures to optimize the diameters of pipelines of heat networks is relevant only in conjunction with the renewal of existing networks in heat supply systems. The production capacities for the mass implementation of projects of such a scale as the overhaul of heating networks throughout Russia are not enough.
An important task is to evaluate the efficiency of heat networks, carried out on the basis of a scientifically based system of criteria for comparing various heat supply systems.
1. 1.2 Grade efficiencysystems heat supply
In the analysis of energy efficiency, in general, there are often assessments and judgments calling for the immediate abandonment of the centralized heating system, leaving the centralized water supply, sewerage, electricity. Here are the strange figures of heat losses in networks, sometimes reaching 70 - 80%, but usually not the technique that was obtained following the results. However, the problem of assessing the efficiency of thermal power systems has been and remains unresolved in full. This is especially true for housing and communal facilities.
The existing indicators for measuring the energy performance of buildings are mainly based on the specific heating characteristic, which is an approximate calculation of the consumption of thermal energy in a building or in sectoral (regional) indicators of specific heat consumption per volume unit or per person. Practical assessment of the efficiency of heat supply systems "at the entrance to the building". Energy, taking into account the cogeneration system, did not show due interest in the overall efficiency of heat distribution directly inside the building, and heating specialists, in turn, leave aside the issues of optimizing the parameters of the heat and power equipment of the building for the heating period.
In conditions where you have not introduced criteria for evaluating the efficiency of the heat supply system as a whole, the requirement to increase the efficiency of heat generating equipment may not lead to an increase in efficiency due to low values of the heat source efficiency and significant heat losses in the external circuit. The diversion of funds from the total investment, for example, the replacement of boilers, will reduce the necessary funds for the replacement of the heating system and, accordingly, increase heat losses. A comprehensive consideration of heating systems, using the overall efficiency of the system and using the unit heating costs of 1 m3 of the building, broken down into production, transport and consumption of thermal energy, will allow prioritization of energy efficiency measures for each system.
If to assess the efficiency of thermal energy sources, to a large extent, it is possible to use the existing efficiency, set, etc., the total efficiency of heat supply systems, taking into account commodities, it is difficult to express the existing criteria. Informational and methodological "discord" hinders a consistent policy of energy conservation in industry, energy and housing and communal services. . As the most appropriate approach to assessing the efficiency of heat and power systems, the use of the functional method.
Obviously, the indicators for assessing the functional efficiency of the system, in essence, since the successful implementation of the functions of a complex system involves both efficient work subsystems and the relationship and coordination of their functioning at different levels and in general. In this case, the main functions of the heating system are identified and evaluated, if necessary, each of them can be delegated to another subsystem, etc.
As such basic functions in the whole complex are the following:
The function of generating heat at the source (CHP, boiler room);
The function of supplying heat carrier to buildings (heat networks);
Functions of distribution and removal of heat to the building (CHP);
Building heat preservation function;
Heat regulation function.
In the case when consumption is removed from the energy source, the modes of operation of the energy transport system are largely determined by consumers. It manifests itself differently for closed and open heating systems.
As a set of energy efficiency indicators for heat networks, the following options have recently been proposed:
1) specific consumption of network water per attached heat load unit.
2) specific consumption of electrical energy for the transport of the coolant.
3) the temperature of the water supply network and return pipelines or the temperature of the water in the return pipeline, depending on the temperature of the network water in the supply pipeline, according to the temperature chart.
4) loss of thermal energy in thermal transport, including through insulation and water leakage.
5) network water losses.
These indicators must be established by the heat network project in order to be carried in the heat network passport and verified during an energy audit (energy audit). The main indicator, i.e. the amount of heat transferred to the energy highway, or the difference between the temperatures of the supply and return water is largely determined by the ability of the building heating system to give this heat to the buildings. The more heat taken away by the building, the more the network is transferred with an equal flow of network water.
Moreover, this "generation" of heat capacity practically does not depend on the thermal resistance of the building envelope, but is determined only by the intensity of heat transfer from the batteries and their total area. Cold reacts "boxes" of the building, and heating costs are determined solely by the operation of the heating system. This is a functional contradiction, an imbalance in the absence of adequate regulation of people to eliminate and correct their actions - either insulated at home, including heating, or actively opening a window for ventilation.
It doesn't matter at all how the energy building is really required. Direct heat transfer energies according to their rate-resurrection schedule. Of course, payment in this case is charged for a "kit" amount of energy, based on the provider's modes. It is not difficult to guess that in this case the heating is not very interested in saving energy, since this reduces the supply of thermal energy and the amount you pay for it.
The main goal of heat supply regulation in heat supply systems is to maintain comfortable temperature and humidity in heated rooms when external climatic conditions change during the heating period and a constant temperature of the water entering the hot water supply system at a variable flow rate during the day. This condition is one of the criteria for evaluating the effectiveness of the system.
1.1. 3 Regulationthermalmodes
Optimization of thermal-hydraulic regimes and efficiency of DH work largely depends on the applied method of heat load regulation.
The main control methods can be determined from the analysis of the joint solution of the equations of the heat balance of heaters according to known formulas and depends on:
coolant temperature;
coolant flow;
Heat transfer coefficient;
Heat transfer surface area. Centralized regulation of heat sources can be done by changing two parameters: temperature and heat carrier flow. In general, the regulation of heat supply can be carried out in three ways:
1) quality - which consists in regulating the supply of thermal energy by changing the temperature of the heat carrier at the inlet to the device while maintaining a constant amount of heat carrier supplied to the control unit;
2) quantitative, which consists in regulating the release of heat by changing the flow rate of the coolant at a constant temperature at the inlet to the control device;
3) qualitative and quantitative, which consists in regulating the release of heat by simultaneously changing the flow rate and temperature of the coolant.
To maintain comfortable conditions inside buildings, regulation should be at least two levels: Central (heat sources) and local (heat points).
In most cities of Russia, centralized regulation, as a rule, is the only type of control and is carried out mainly for heating the load or the combined load of heating and hot water supply by changing the temperature of the coolant in the return pipeline depending on meteorological parameters, primarily air temperature, while as a conditionally constant coolant flow.
Widely used in class schedules for proper regulation of the heat load shows the dependence of the temperature of the coolant supply and return pipelines depending on the outdoor temperature. The graphs are calculated according to known formulas, which are obtained from the balance equation of the heating device at the calculated temperature and other conditions.
Methods for calculating the temperature graphs of Central control was originally developed for the design of heating systems, so they adopted a number of assumptions and simplifications, in particular, the condition of stationarity of heat transfer processes. In reality, all heat transfer processes occurring in the elements of the heating system are non-stationary, and this characteristic should be taken into account when analyzing and regulating the heat load. In practice, however, this feature is not taken into account and the design of graphs used in operation and operational management.
The thermal regime of the building is formed as a result of the cumulative effect of constantly changing external (changes in outdoor air temperature, wind speed and direction, intensity of solar radiation, air humidity) and internal (changes in the release of heat from the heating system, heat in cooking, lighting work, exposure to solar radiation through glazing, heat emitted by people) disturbances.
The main parameter in determining the quality of heat supply and creating a comfortable environment is maintaining the temperature of the internal air within the tolerance of ± (K2) ° С.
The main method of operational control of thermal loads were described in the "rules for the use of thermal and electric energy", which on 01.01.2000 was canceled by order of the Ministry of Energy of the Russian Federation No. 2 of 10.01.2000. These rules ensure the regulation of the temperature of the heat carrier in the supply pipeline in accordance with the temperature schedule with a change step based on predicting the expected outdoor temperature twice a day with a temperature difference between day and night of at least 8 ° C and once a day the temperature change is less than 8 ° WITH.
In accordance with the current regulatory documents, the regulation of the heat load is provided by changing the temperature of the heat carrier in the supply line in accordance with the approved heat supply system. , climatic conditions and other factors.
Despite the straightforward wording of this paragraph in these guidelines, this task is extremely challenging task under the conditions of uncertainty of external factors, the complexity of supplying the scheme, predicted data based on the actual state of the equipment of the district heating system, first of all, heat networks. According to statistics and numerous analytical materials, the wear of heat supply equipment is about 60-70% and continues to grow due to a significant drop in the replacement of the pipeline. An analysis of pipeline damage shows that the bulk of damage occurs in the process of changing the coolant temperature due to changes in stresses in pipelines.
Forecasting the dynamics of changes in indoor air temperature in rooms for any predicted temperature changes environment taking into account the dynamic properties of the heating system, it makes it possible to develop a dispatch schedule for thermal loads with a constant temperature of the coolant in a much longer time interval. . The quality of warmth and comfort of the end user is not worse. However, the degree of automation of the heat load, connection schemes and hydraulic resistance should be taken into account, after studies of the operating conditions of the heat exchange equipment of heat points show that a decrease in the temperature of the coolant in the supply pipeline by 1 °C:
In automatic heating load control systems, it depends on the connection scheme
Increase circulation flow rate to 8%;
In automatic heating control systems, an independent circuit for connecting the load to a significant increase in flow in the primary circuit (up to 12% per degree), and to increase the temperature of the coolant in the return pipeline by 1 °C;
Domestic hot water systems in closed connection schemes to increase the circulation flow by up to 20% and increase the temperature of the coolant in the return pipeline by 1°.
Increasing coolant flow increases pressure loss. Therefore, this provision is possible from the point of view of the sufficiency of hydraulic resistance and reserve equipment of the PNS. It should also be noted that the systematic decrease in temperature in the supply pipe leads to an increase in coolant flow and subsequent razregulyatsii the entire heating system. .
Thus, the development of a schedule for dispatching and centralized heat regulation must be carried out taking into account the dynamic characteristics of power supply systems, the possibility of storing buildings and the variability of external and internal influences. Increasing the regulation period to 24-48-72 hours or more, within certain limits of changes in external and internal influences, does not affect the quality of heat supply to consumers, which gives you the opportunity to operate the equipment in a "soft" mode.
Operational control based on the above characteristics leads to:
1) reduce the likelihood of damage to pipelines and improve reliability;
2) efficiency improvement:
Energy production due to the difference in increments of fuel consumption for energy production at CHPPs at different coolant temperatures;
In the transport and distribution of thermal energy, due to the difference, an increase in the heat losses of pipelines at different temperatures of the coolant;
3) reduce the number of start-stops of the main heat generating equipment, which also increases reliability and efficiency.
Optimization of operating modes of heat networks refers to organizational and technical measures that do not require significant financial costs for implementation, but lead to a significant economic result and reduce the cost of fuel and energy resources.
1.1.4 OptimizationAndadjustmentmodesworkthermalnetworks
Almost all structural divisions of "heat networks" are involved in the management and adjustment of the operating modes of thermal networks. They develop optimal thermal and hydraulic regimes, as well as measures for their organization, analysis of actual regimes, analyze measures and adjustments of design and estimate documentation, as well as operational control of regimes, control heat consumption, etc.
The development of modes (heating and non-heating period) is carried out annually on the basis of an analysis of the operating modes of heat networks and in previous periods, to clarify the characteristics of heat networks and heat consumption systems, it is expected to connect new loads, plans overhaul, reconstruction and technical re-equipment. Using this information, thermal-hydraulic calculations are carried out to compile a list of adjustment measures, including the calculation of throttle devices for each substation. .
In addition to calculating optimal modes and the development of corrective measures allows operational and engineering personnel, including managers, at a modern high-tech level in a single information space to perform:
1) Analysis of the technical condition of the heating system, the actual state of the network mode, damage to pipelines;
2) simulation of emergency situations, including emergency ones;
3) optimization of the inheritance planning priorities of the change pipeline;
4) design and modernization of heat supply systems, including optimization of planning for the modernization and development of heat networks.
The main optimization criterion in the development of modes and redistribution of heat loads is to reduce the cost of production and transportation of heat energy (loading the most economical heat sources, unloading pump stations) within the existing technological limitations (electricity supply and characteristics of heat source equipment, capacity of heat networks and characteristics of pump station equipment). pumping stations, permissible operating parameters of the thermal system, etc.). .
As a result of the systematic work carried out to optimize the operating modes of heat networks, over the past few years, the quality of heat supply to consumers and the efficiency of the entire district heating system from heat sources have significantly improved, namely:
1) reduction of excessive fuel consumption due to overheating of consumers during transitional periods;
2) reduction of electricity consumption for pumping the coolant by 10% due to a decrease in the circulating flow of the coolant when connecting new consumers;
3) reduction of fuel consumption for power generation due to repairs and lowering the temperature of the return network water;
4) completely eliminate the operation of "reboot" heat consumption systems due to the lack of disposable heads;
5) reduction of make-up water consumption by 11%;
6) new consumers are connected.
Most of the heat networks are hydraulically misregulated, or otherwise the objects receiving heat from the coolant are proportional to their heat load, which leads to overheating (or underheating) of these objects, which causes indignation of consumers.
1.1.5 Regulationhydraulicregimethermalnetworks
Heating networks are an important element of any heat supply system. Transportation of thermal energy requires large capital investments, commensurate with the costs of building a thermal power plant and large boiler houses. Improving the reliability and durability of heat transport systems is the most important economic task in the design, construction and operation of heat pipes. The solution to this problem is inextricably linked with the problems of energy saving in heat supply systems. .
The most common in the country, including in the Vologda Oblast, is the method of generating heat energy for consumers at a constant coolant flow rate. The amount of thermal energy supplied to consumers is regulated by changing the temperature of the coolant. It is assumed that each consumer will receive from the total consumption of a certain amount of coolant proportional to its heat load.
As a rule, this condition is not preserved for a number of objective and subjective reasons, which leads to a decrease in the quality of heat supply in certain areas. To solve this problem, heat supply organizations increase the flow of coolant to the system as a whole, which leads to increased energy costs, increased coolant leakage and excessive fuel consumption.
To solve these problems through periodic measures to optimize the hydraulic regime of the heating network, the main goal of which is to ensure the distribution of the coolant in the network in proportion to the thermal loads of consumers. .
Of the large number of energy-saving measures to optimize heat supply, the hydraulic modes of heat networks (hereinafter referred to as the regulation) are the most effective (with a small investment capital, it gives a great economic effect). In addition, the quality of heat supply has improved. As a rule, the adjustment consists of three stages:
Calculation of hydraulic modes of heating networks and development of recommendations;
Preparatory work;
Holding installation work in networks and at objects of heat consumption devices, distribution of the total flow.
The optimal parameters of the heat network are calculated using a simplified formula:
where \u003d 10 -3 Gcal / m 3 C - heat capacity of water;
Estimated (optimal) water consumption in the network, t/h;
Estimated (optimal) temperature chart of the boiler house, C;
In real (without regulation) heating networks, the following main options are possible:
1. In the heating system, low coolant flow rates and a temperature graph. In this case, the adjustment does not lead to energy savings and is aimed at improving the quality of heat supply.
2. In the heating system, excessive coolant consumption and low temperature curve. In this case, the adjustment leads to a reduction in the cost of electricity consumed for transportation by the carrier.
3. In the heating system, there is an excessive flow of coolant and there is an optimal temperature graph. In this case, the adjustment leads to savings in thermal energy. .
The third case is the most general and one can move from it to other options when calculating the economic effect.
Heating networks are shimmed in order to distribute heat carrier flows between consumers in accordance with their needs.
1.1.6 Puckingthermalnetworks
Without regulation, hot water from the heat source mostly enters buildings located near the boiler house. The remaining small volume of water is sent to the periphery. Remote buildings lack heat, they freeze, while in nearby buildings there is overheating. People, opening the windows, literally heat the street.
To prevent this from happening, restrictive washers with a calibrated hole of a smaller cross section than the pipeline are installed on the branches of heating networks to buildings. This makes it possible to increase the volume of coolant for remote buildings. .
Washers (hole size) are calculated for each house depending on the required amount of heat. Positive result from the washer of heat networks can be obtained only in the case of 100% coverage of all buildings connected to the heat network. In parallel with the washer, it is necessary to bring the operation of the pumps in the boiler room into line with the hydraulic resistance of the heating network.
After installing the washers, the coolant flow through the pipelines of the heating network is reduced by 1.5-3 times. Accordingly, the number of operating pumps in the boiler room also decreases. This results in savings in fuel, electricity, chemicals for make-up water. It becomes possible to increase the temperature of the water at the outlet of the boiler room.
Pucking is necessary not only for regulating external heating networks, but also for the heating system inside buildings. The risers of the heating system, located further from the heat point located in the house, receive hot water less, it's cold in the apartments here. It is hot in apartments located close to the heat point, since more heat carrier is supplied to them. The distribution of coolant flow rates among risers in accordance with the required amount of heat is also carried out by calculating washers and installing them on risers. .
Washing the heating system is carried out in stages:
1) Inspection of the main pipelines of the heating system in the basement and in the attic (if any). Drawing up an executive diagram of the heating system indicating the diameters of pipelines, their lengths, locations of fittings (in the absence of a project). Collection of data on the temperature of the internal air in apartments, specifying in which apartments it is warm, in which it is cold. Analysis of the reasons for the unsatisfactory operation of the heating system, identification of problematic risers (apartments)
3) Verification of the implementation of the recommended activities. Analysis of the new steady state after washing the heating system. Correction of the size of washers in places where the required result is not achieved (by calculation). Dismantling of washers requiring adjustment, installation of new washers. On internal systems ah heating washers can be installed both in winter and in summer. Check their work - only in the heating season.
Washing costs are low - this is the cost of the washers themselves and their installation on risers. The cost of work to regulate internal heating systems depends on the heat output of the building (number of risers).
The minimum price is 40 thousand rubles. at the heat output of the heating system up to 0.5 Gcal/h. The price of regulating the heating system of a multi-sectional house can reach up to 150 thousand rubles. The increase in the cost of work occurs when there is no project documentation. In this case, it is necessary to take a full-scale survey of the heating system and its measurements (diameters, lengths of pipelines, valve locations). .
Adjustment of water heating networks is carried out to ensure normal heat supply to consumers. As a result, setups are created the necessary conditions for the operation of heating systems, supply ventilation, air conditioning and hot water supply and increase the technical and economic indicators of district heating by increasing the throughput of heat networks, eliminating overheating of consumers, reducing electricity consumption for pumping coolant.
1.1.7 Mainprovisionsadjustmentsthermalnetworks
Adjustment of heat networks is carried out at all levels of the district heating system in the heat-preparation plant of the heat source, heat networks, heat points and heat consumption systems. .
Start-up and adjustment works in thermal networks are carried out in three stages:
Study and test the district heating system with the subsequent development of measures aimed at ensuring the efficiency of its work;
To implement the developed activities;
Regulate the system.
The study shows the actual operating modes, indicate the type and condition of the heating system of the equipment, determine the nature and magnitude of thermal loads, the need and scope for testing heating networks and equipment. .
In the process of commissioning in thermal networks, they test the network capacity and communications of heat sources, determine the actual characteristics of network pumps, testing energy savings. If necessary, heating networks suffer from heat loss, strength and compensating capacity at the maximum temperature of the network water.
The development of regimes and measures to ensure the operability of heat networks is carried out on the basis of survey and test data in the following order:
The actual heat load is calculated;
Develop a heat transfer mode;
Determine the estimated costs of network water;
Perform hydraulic calculation of external heat networks, and, if necessary, heat consumption systems of industrial buildings;
Development of the hydraulic regime of heating networks;
Expect a choke and agitator for heating consumers and private buildings;
Determine the installation locations of automatic regulators at the heat source, heating networks and consumers; make a list of actions that should precede the adjustment.
In the implementation of measures for the adjustment of thermal networks, the following is carried out:
Eliminate defects in building structures and equipment;
Bring the schemes and equipment of the water heating installation, heating system, booster pumping stations, heating points and heat consumption systems in accordance with the recommendations, based on the calculations and developed thermal and hydraulic modes;
Equip all parts of the heating system, the necessary tools in accordance with the requirements of regulatory documents;
Automate individual components of the heating system;
Organize and regulate the pumping station;
Install throttle and mixing devices. .
The control of district heating systems will only begin with a review to determine the effectiveness of all design adjustments. In the process of checking the adjustment of thermal installations, when the heat source is at the calculated thermal and hydraulic modes, as well as the actual coolant design flow, adjusting the diameters of the openings of the elevator nozzles and throttle diaphragms, setting the automatic regulators.
The efficiency of setting up heat networks is characterized by the following indicators: reduction of fuel consumption due to the elimination of overheating of heat consumption systems; reduction of energy consumption for pumping the coolant by reducing the specific water consumption and shutting down unnecessary pumping stations; ensuring connection to networks of additional thermal resistance; reduction of fuel consumption for electricity generation by reducing the temperature of the water in the return pipeline of the heating network (district heating systems). .
Reliability of supply is a characteristic of the state of the heat supply system, which will ensure the quality and safety of heat supply.
1.1.8 Reliabilityheat supply
Every winter, news agencies are full of news about accidents in heating networks and boiler houses, thawed houses, freezing children. According to the official data of the State Construction Committee, in separate periods up to 300 thousand people “froze” in the country, but this figure most likely does not fully reflect reality, because local authorities tend to hide emergencies. As for underheating (i.e. if the apartments are + 10-15 ° C), then this is not taken into account at all, statistics are not kept, and you can get into the report of the Ministry of Emergencies only if there is a burst pipe and a defrosted system. Thus, according to official and unofficial data, millions of people freeze every year in Russia, and responsible persons hone their arguments, explaining the reasons for the wear and tear of equipment, heating networks and lack of money. Even according to the official statements of the State Construction Committee, a third of accidents occur on heating networks due to their dilapidation.
At the request of the Chairman of Gosstroy, 30% of accidents in heat supply systems occur due to incorrect actions of personnel. Therefore, the main question is not what system provides the user with heat - centralized or decentralized, and how to ensure its high-quality work. The low level of exploitation will manifest itself in any case. If the company cannot ensure the normative service life of pipelines when the widespread installation of local boilers, the relevant work will be affected during the first heating season.
From the foregoing, we can draw the following conclusion: the way out of this situation is to restore elementary order. Not all the time only to deal with the consequences of the disease, to invest heavily in patching holes, and the annual replacement of pipes in the same areas that failed for the same reasons.
It is necessary to eliminate the causes themselves, with minimal efforts to protect against corrosion, it will give a much greater effect: for example, extending the life of the pipeline for 5 years only due to drainage channels (minimum costs for drainage wells and pumping water), will provide savings from reducing heat loss and the cost of repairing pipeline damage is equal to the cost of moving from the same area.
The main laying of heating networks (more than 90% of the total) in Russia is underground laying in impassable and through channels.
1.1.9 Modernheat-insulatingmaterialsForthermalnetworks
The channel strip, according to leading organizations and industry experts, has a number of advantages that make it the main strip in Russia today and in the long term. .
The advantages of channel laying include: reduction of stresses in the metal due to the possibility of free expansion of pipelines; protection of pipelines from damage during excavation of other communications, prevention of the release of coolant to the surface of the earth when pipelines break; no vehicle restoration costs (for existing networks).
Channelless laying using pre-insulated pipes is used where it is technically impossible or economically Neil, in accordance with the arrangement of drainage systems to prevent channel flooding groundwater and atmospheric precipitation. Select The type of lane is determined by site conditions. .
The norms and rules for the design of underground pipelines all the way to the KR strip, including the channel strips, are regulated by SNiP 41-02-2003 "Heat Networks". Requirements for structures, insulation standards and heat losses from heat-insulated pipelines, depending on the diameter of the pipes, the temperature of the coolant and the type of installation (above-ground or underground), are determined by SNiP 41-03-2003 "Thermal insulation of equipment and pipelines".
Most heating networks in Russia have been in operation for many years and were designed in accordance with the regulations for thermal insulation of pipelines, which were significantly lower than the current ones.
Lack of standard technical solutions, unreasonable use of heat-insulating materials without taking into account their purpose, non-compliance regulatory requirements, poor-quality work, non-specialized organizations, lack of systematic control and timely repair of thermal insulation - all this leads to excessive losses of thermal energy in industry and housing and communal services.
1.2 conclusionsAndclarificationsproductionstasks
Most of the heat networks in Russia are hydraulically deregulated, or otherwise heat-consuming objects receive the amount of coolant not proportional to their heat load, this leads to overheating (underheating) of these objects, which causes consumer disturbance. Therefore, the objectives of this work are: analysis of measures to adjust the hydraulic regime of heating networks; development of technical solutions; adjustment of the hydraulic regime and feasibility study of measures.
2 . DESCRIPTIONANALOGUESWAYSANDDEVICES
2.1 Analoguesdissertationworks
2.1.1 Raiseefficiencytechnologiessubstitutionsdefectivesitemainpipeline
The purpose of the dissertation work: to increase the efficiency of work on the replacement of a defective section of the main pipeline.
To achieve this goal, the following research objectives are formulated:
Analysis of the technology for replacing a defective pipeline section;
Evaluation of the efforts applied to center the pipes and
stress-strain state of pipelines during their alignment;
Development of rational technological schemes alignment of the pipeline when replacing a defective section;
Improving the technology of closing the cavity of the pipeline, which increases the safety of welding.
2.1.2 Optimizationthermal protectionpipelinesAndequipmentthermalnetworks
The purpose of the dissertation work: Improving methods for optimizing the calculation of thermal protection of pipelines, equipment and substantiating the methodology for choosing thermal insulation materials to improve the performance and efficiency of heat networks with the development of the necessary software.
2.1.3 Monitoringreliabilitythermalnetworks
The purpose of the dissertation work: Development of a system for monitoring the reliability of heating networks in order to increase their reliability, the validity of the accepted engineering solutions By maintenance heating networks and their repair.
2.1.4 RaiseefficiencyworksystemscentralizedthosePsupplythroughoptimizationwarm- hydraulicmodes
The purpose of the dissertation work: This paper discusses the issues of improving the efficiency of district heating water systems by optimizing thermal and hydraulic operating modes. The issues of development, management, control and analysis of thermal-hydraulic regimes are considered on the example of a district heating system. The results of the adjustment are reflected, as well as the features of the operational centralized regulation of thermal regimes, taking into account the dynamic properties of the district heating system.
2.2 Reviewpatents
Patent No. 2386889 for "Pressure Stabilizer"
The invention relates to means for damping liquid and gas pressure pulsations that occur when turning on, operating and turning off pumps, opening and closing valves or gate valves in pipelines for heat and water supply, the oil industry and in mechanical engineering.
Patent No. 2161663 for "The system of cathodic protection of main pipelines against corrosion"
The invention relates to the field of prevention of corrosion of metals, namely the cathodic protection of metals or metal objects, such as pipelines.
Patent No. 2148808 for "Method of in-line flaw detection of main pipelines"
The invention relates to the field of non-destructive testing and can be used for flaw detection of main pipelines during their operation. The method includes moving an inspection projectile - a flaw detector with control and measuring equipment inside the pipeline at a speed lower than the flow rate of the pumped medium with bypassing the flow of the pumped medium through the flaw detector projectile, recording, in accordance with the inspection regulations, by the equipment of the flaw detector projectile the physical characteristics of the pipeline wall material and the distance traveled and determining, based on the results of measurements, the presence of defects in the wall and their location along the length of the pipeline.
The inspected pipeline is divided into separate sections with individual inspection regulations for each section. At the boundaries of the sections above the inspected pipeline, reference beacons are installed, coded reference signals are emitted from the reference beacons in the direction of the pipeline, the intersection of the reference signals of the reference beacons is recorded by the flaw detector projectile equipment and the speed of movement of the flaw detector projectile and the operation of its equipment and recording equipment are changed in accordance with the inspection regulations next section of the pipeline. The technical result of the invention is the optimization of the mode of inspection of individual sections of the pipeline, increasing the accuracy of determining defects and maintaining the productivity of the pipeline.
2.3 Mainflawsthermalnetworks
Adjusting the hydraulic regime of heating networks is currently one of the most inexpensive and quickly paid back energy-saving measures implemented in heating systems. The long-term practice of making adjustments confirms the high economic and energy efficiency of this hand. .
However, the experience of adjusting the hydraulic regime of heating networks revealed a number of shortcomings that reduce the effectiveness of the method for optimizing the heating system. The results of regulation in the heat supply systems of the Vologda Oblast districts gave paradoxical results. In many cases, the optimization of the hydraulic regime did not bring the expected economic effect, and in some cases led to a decrease in the quality of heat supply to consumers.
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In this article, we continue the topic we started about the heating system of a private house with our own hands. We have already learned how such a system works, talked about which type to choose, now let's talk about how to increase efficiency. 
So, what needs to be done to make it more effective. 
We need the coolant inside to move in the direction we need and in the right amount at a higher speed, while giving off more heat. The fluid in the system must move faster not only through the pipeline, but also through the batteries connected to it. I will explain the principle of operation using the example of a two-pipe system with a lower wiring.
In order for water to enter the batteries connected to the pipe, it is necessary to make a brake at the end of this supply pipe, that is, to increase the resistance to movement. To do this, at the end (the measurement must be taken from the entrance to the extreme radiator), we install a pipe of a smaller diameter.
In order for the transition to be smooth, they must be installed in this order: If the input to the radiator is 20 mm (standard for new-type batteries), then the supply pipe (outlet for radiators) must be at least 25 mm.
Then it smoothly, after 1-2 meters, passes into a pipe whose diameter is 32 millimeters, then according to the same scheme - 40 millimeters. The rest of the distance of the system or its wing will be a supply pipe with a diameter of 40-60 mm or more.
In this case, when the boiler is turned on, the coolant begins to move through the system and, having encountered resistance on its way, it will begin to move in various other directions (to the radiators), equalizing the total pressure.
We thus increased the efficiency of the supply pipe and the first half of the system. And what happens in the other half, which is, as it were, a reflection of the first.
And since this is a mirror image, then the processes in it occur exactly the opposite: in the supply pipe of the return, the pressure decreases (due to a decrease in the temperature of the liquid and an increase in diameter) and a suction effect appears, helping the initial pressure to increase the speed of water not only in the pipeline, but also in heating batteries.
By increasing efficiency, you will not only make your home warmer, but also save a lot of money.
Video: Heat in the house - heating: Increasing the efficiency of the battery / water heating radiator
Ph.D. E.G. Gasho, Ph.D. S. A. Kozlov,
JSC Association VNIPIenergoprom, Moscow;
Ph.D. V.P. Kozhevnikov,
Belgorod State Technical University named after V.I. V.G. Shukhov
The problem of creating a reliable, sustainable, efficient energy supply for utility and technological complexes is often replaced by far-fetched dilemmas in the selection of energy sources, persistent propaganda of the autonomy of heat and power supply, while actively referring to selected foreign experience. The increase in transaction costs (i.e., the costs of distribution and delivery of fuel and energy resources to consumers) in district heating (DH) systems has generated a whole wave of measures to separate networks, the emergence of various autonomous sources of thermal energy different power serving directly buildings, and ultimately, to individual heat generators. The division of DH systems into autonomous and quasi-autonomous elements and blocks, undertaken ostensibly in order to increase efficiency, often only leads to additional disorganization and confusion.
The backlog in the construction of heat networks, not always timely introduction of heat loads from industry and housing and communal services, overestimation of heat loads from consumers, changes in the composition and technology of enterprises led to an unacceptably long (10-15 years) period for bringing turbines to design parameters with a full load of extractions. It is precisely the shortcomings in the structural development of heat supply systems (lack of peak units, underdevelopment of networks, lag in the commissioning of consumers, overestimation of the calculated loads of consumers and orientation towards the construction of powerful CHPPs) that led to a significant decrease in the estimated efficiency of heating systems.
The comprehensive and massive crisis of the country's life support systems is based on a complex of reasons, including not only the rise in fuel prices, depreciation of fixed assets, but also a significant change in the design operating conditions, the heat load schedule, and the functional composition of the equipment. In addition, a significant share of the industrial complex and related energy sources, and this is at least 30-35% of the total energy consumption, after the collapse of the USSR ended up outside of Russia. A significant number of powerful energy facilities, power lines, pipelines, power engineering plants are located on the territory of neighboring states (Kazakhstan, Ukraine, Belarus, etc.). Corresponding breaks in technological connections and energy and fuel supply systems served as an additional factor in the deterioration of the conditions for the functioning of life support systems.
The predominance of the CHPP industrial load, which exceeded the heating load almost twice, largely smoothed out the seasonal peaks in municipal heat consumption in cities. A sharp reduction in industrial heat consumption has led to an overabundance of centralized capacities with an increase in the role of peak sources and units. The problem is more acute in major cities with a high proportion of industrial energy consumption, in small cities the system more easily reaches the calculated parameters.
Foreign experience
Most of the works actively promoting autonomous systems heating, consider it their duty to refer to the Western experience, in which there is practically no place for thermal power plants and "giant wasteful heating mains." Actual European experience testifies to the contrary. So, in Denmark, largely under the influence of Soviet practice, it was district heating that became the basis of housing infrastructure. As a result of the implementation of the state program, by the mid-1990s. the share of DH systems in this country was about 60% of the total heat consumption, and in large cities - up to 90%. More than a thousand cogeneration units were connected to the district heating system, providing heat and electricity to more than 1 million buildings and industrial facilities. At the same time, the consumption of energy resources per 1 m 2 only for the period 1973-1983. decreased by half. The reasons for the striking differences between Russia and Denmark lie in the initial investment and the ability to operate heating networks. The effectiveness of the Danish example is due to the introduction of new materials and technologies ( plastic pipes, modern pumping and shut-off equipment, etc.), which contributed to a visible reduction in losses. In the main and distribution pipelines in Denmark, they make up only about 4%.
The use of DH systems for heat supply to consumers in individual countries of Central and Eastern Europe is shown in fig. 1.
For example, the rationalization of heat supply in East Berlin was based on the phased replacement, reconstruction of highways, the installation of metering and control units, the use of more advanced circuit and parametric solutions and equipment. In buildings before reconstruction, there were significant "overflows" and uneven distribution of thermal energy both in the volume of buildings and between buildings. About 80% of the buildings were reconstructed, in 10% the heat supply systems were completely replaced, in the process of reconstruction of internal and transition from one-pipe systems in buildings to two-pipe ones, the areas of heating devices were recalculated, water consumption in heating systems of buildings was calculated, new control valves were ordered. Heating devices were equipped with valves with thermostats, control valves were installed on the risers of buildings.
The connection systems as a whole were replaced with independent ones, a transition was made from the central heating station to the ITP, the coolant temperature was reduced to 110 °C. The water consumption in the system was reduced by 25%, temperature deviations for consumers decreased. The circulating heating networks of buildings are used to heat water in the DHW system. Currently, there are no limits on the thermal power of sources, there are restrictions only on the throughput of pipelines.
Residents' hot water consumption was over 70-75 l/day, after the re-equipment of the system it decreased to 50 l/day. The installation of water meters additionally led to a decrease to 25-30 l / day. In general, the totality of measures and circuit solutions led to a reduction in the cost of heating buildings from 100 W/m 2 to 65-70 W/m 2 . Laws in Germany prescribe a regulatory reduction in energy costs from 130 kWh/m 2 .yr in 1980 to 100 kWh/m 2 .yr in 1995, and to 70 kWh/m 2 .yr by 2003 G.
Domestic experience
A significant number of works on the installation and adjustment of energy metering systems indicate that the maximum heat losses are observed not in the networks, as mentioned above, but in buildings. Firstly, these inconsistencies were found between the contractual values and the actual amount of heat received. And, secondly, between the actually received and the required amount of heat for the building. These discrepancies reach 30-35%! Of course, it is necessary to reduce heat losses during transportation through heating networks, although they are significantly lower.
It is also necessary to note the presence of "overheating" in residential buildings, which are due to various factors. Buildings are designed for the same load, but in fact some consume more heat, others less. Usually people complain little about "overheating". And, most likely, if the apartment has its own boiler, the heat savings are not so big, because a person, having got used to such temperature conditions, will give as much heat as he needs to provide himself with comfortable conditions.
The actual values of specific energy consumption by buildings, depending on the thermal resistance of the fences, are shown in fig. 2. The upper trend line - according to the actual values of specific energy costs, the lower one - the theoretical balance costs for buildings, with an average standard value for Moscow q = 0.15-0.21 Gcal/m 2 .year. The lower trend line in fig. 2 - functional balance values necessary to maintain standard temperatures in buildings. These values (actual and theoretical) are close in the zone of insufficient thermal resistance R=0.25-0.3 K.m 2 /W, because in this case, the buildings require a significant amount of heat. One of the points close to the lower trend with R = 0.55 K.m 2 /W belongs to a complex of buildings in the Meshchansky district of the Central Administrative District of Moscow, in which a complete flushing of the heating system was carried out. The comparison shows that a number of buildings in the city, being “exempted” from 15% of “overheating”, fully meet modern European energy efficiency requirements.
It can be seen that the actual energy consumption values for buildings with acceptable thermal resistances deviate quite a lot from the theoretical balance curve. The degree of deviation of the actual points from the ideal lower curve characterizes inefficient operating modes, wasteful waste of energy, and the degree of coincidence - the relative efficiency compared to the optimal base (balance) option. In particular, according to the lower base curve, it is advisable to calculate the minimum required limits for heat consumption of buildings and structures, based on the actual or predicted temperatures of the heating period.
The identified "overheating" of a significant number of city buildings casts doubt on some of the stereotypes that have developed recently associated with indicators of the energy efficiency of public utilities. A comparative analysis shows that a number of city buildings consume heat per unit area in terms of the Berlin climate even less than required by the European standards of 2003.
Specific implementation of apartment heating projects
Since 1999, Gosstroy of the Russian Federation (now the Federal Agency for Construction and Housing and Utilities of the Russian Federation - Rosstroy) has been experimenting with the construction and operation of multi-storey buildings with apartment heating. Such residential complexes have already been built and are successfully operating in Smolensk, Serpukhov, Bryansk, St. Petersburg, Yekaterinburg, Kaliningrad, Nizhny Novgorod. The largest experience in the operation of wall-mounted boilers with closed camera of combustion has been accumulated in Belgorod, where a quarterly building of houses is being carried out with the use of apartment heating systems. There are put-
A good example of their operation is also in the northern regions - for example, in the city of Syktyvkar.
The city of Belgorod was one of the first cities in Russia (in 2001-2002) to use apartment heating in new multi-apartment residential buildings. This was due to a number of reasons, including, as it seemed to everyone before, large heat losses in the main and distributing heat networks. As well as quite active construction of residential multi-storey buildings, which was primarily due to the influx of money from the North. As a result, in a number of cases, some buildings were equipped with individual space heating systems.
Boilers of both domestic and foreign manufacturers were used for apartment heating. Several buildings with similar systems were erected quite quickly and without connection to heating networks (in the city center, in its southern part). The autonomous heating system in the building is as follows. The boiler is located in the kitchen, from which the chimney pierces the balcony (loggia) and “cuts” into the common chimney, which goes up and rises several meters from the top floor.
The chimney in this case is several times lower than that of a conventional quarterly boiler house, it is natural to expect large surface concentrations of emitted components. In specific conditions, it is also necessary to compare other factors (fuel economy, reduction in gross emissions, etc.).
Of course, from the point of view of domestic comfort, apartment heating at first seems more convenient. For example, the boiler turns on at lower outdoor temperatures than in the case of using the central heating system (approximately at t nv = 0 -–2 °C), because acceptable temperature in the apartment. The boiler turns on automatically when the temperature inside the room decreases, to which the residents set it. Also, the boiler automatically turns on when there is a load on the DHW.
Almost the first an important factor here it is not the apartment wiring, but the thermal resistance of the building (the presence of large loggias, which people additionally insulate). In the absence of proper operating experience, it is still difficult to make an adequate comparison of unit heating costs in the case of an apartment system and in the case of DH, we hope that such an opportunity will be presented to us later.
When assessing the financial costs of the apartment heating system during active operation, the depreciation of boilers, their full cost (for residents), etc. were not always taken into account.
A correct comparison can only be made under comparable energy conditions. If you look at it in a complex way, then the system of apartment heating is not so cheap. It is clear that individual comfort with the possibility of such distributed regulation always costs more.
What was gained during the operation of the apartment heating system on the example of Belgorod
1. Unheated zones appeared in residential buildings: entrances; stairwells. It is known that for the normal operation of buildings it is necessary to provide heating of all its premises (all zones). For some reason, at the design stage of residential buildings, this was not thought about. And already during their operation, they began to come up with all sorts of exotic ways of heating non-residential areas, up to electric heating. After that, the question immediately arose: who will pay for the heating of non-residential areas (for electric heating)? We began to think about how to “scatter” the fee on all residents, and how. Thus, residents have a new item of expenditure (additional costs) for heating non-residential areas, which, of course, no one took into account at the design stage of the system (as mentioned above).
2. In Belgorod, as in a number of other regions, a certain proportion of housing is bought by the population for the future. This primarily concerns housing for the "northerners". People, as a rule, pay for all housing services provided to them, but they do not live in apartments or live on short trips (for example, during the warm season). For this reason, many apartments also became cold (unheated) areas, which led to a deterioration in thermal comfort, as well as a number of other problems (the system is designed for general circulation). First of all, there was a problem associated with the inability to start the boiler in unheated apartments due to the absence of their owners, and it is necessary to compensate for heat losses (at the expense of neighboring premises).
3. If the boiler is out of operation for a long time, it requires some preliminary inspection before starting. As a rule, boilers are serviced by specialized organizations, as well as gas services, but, despite this, the issue of servicing individual heat sources in the city has not been fully resolved.
4. The boilers used in the apartment heating system are equipment high level and, accordingly, require more serious maintenance and preparation (service). Thus, an appropriate energy service (not cheap) is required, and if the HOA does not have the funds to carry out this kind of service?
Distributed regulation of heat consumption
Both rooftop boilers and apartment systems are most efficient only when natural gas can be used as fuel. As a rule, there is no reserve fuel for them. Therefore, the possibility of limiting supplies or increasing the cost of gas urgently requires a search for new solutions in the future. In the electric power industry, for this purpose, capacities are being introduced at coal, nuclear and hydroelectric power plants, local fuel and waste are used more actively, and there are promising solutions for the use of biomass. But it is economically unrealistic to solve the issues of heat supply through electric power generation in the near future. The use of heat pump installations (HPU) is more efficient, in this case, electricity consumption is only 20-30% of the total heat demand, the rest is obtained by converting low-potential heat (rivers, soil, air). To date heat pumps widely used throughout the world, the number of installations in the US, Japan and Europe is in the millions. In the USA and Japan, air-to-air heat pumps are most widely used for heating and summer air conditioning. However, for harsh climates and urban areas with a high heat load density, obtain the required amount of low-grade heat during peak loads (at low temperatures outside air) is difficult; in the implemented projects, large HPPs use the heat of sea water. The most powerful heat pump station (320 MW) operates in Stockholm.
For Russian cities with large heating systems, the most relevant issue is the effective use of HPP as an addition to existing district heating systems.
On fig. 3, 4 shown circuit diagram DH from a steam turbine CHP plant and a typical temperature graph of network water. For an existing micro-district, when supplying 100 t/h of network water to the central heating substation with temperatures of 100/50 °C, consumers receive their own 5 Gcal/h of heat. A new facility can receive another 2 Gcal / h of heat from the same network water, when cooled from 50 to 30 °C, which does not change the consumption of network water and the cost of its pumping, and is provided without transfer by the same heat networks. It is important that in accordance with the temperature chart of the return network water, it is possible to obtain an additional amount of heat precisely at low outdoor temperatures.
At first glance, the use of HPP, which uses return network water as a heat source, is uneconomical when taking into account the full cost of heat. For example, the operating costs for obtaining “new” heat (at the tariff of Mosenergo OJSC according to the Decree of the REC of Moscow dated December 11, 2006 No. 51 for heat 554 rubles / Gcal and for electricity 1120 rubles / MWh) will be 704 rubles/Gcal (554x0.8+1120x0.2x1.163=704), i.e. 27% higher than the heat tariff itself. But if the new system allows (there is such a possibility, which is the subject of further consideration) to reduce heat consumption by 25-40%, then such a solution becomes economically equivalent in terms of current operating costs.
We also note that in the structure of the tariff for OAO Mosenergo, the tariff for heat production is only 304 rubles/Gcal, and 245 rubles/Gcal is the tariff for heat transport (sales allowance is 5 rubles/Gcal). But the transfer of additional low-grade heat did not increase the cost of its transportation! If we exclude, which is quite justified, the transport component for HPI, then we get the operational component of the cost of "new" heat from HPI is already only 508 rubles/Gcal.
Moreover, in the future, it is realistic to introduce different tariffs for heat from CHPs - depending on the potential - because lowering the temperature of the return network water and additional heat supply provide CHPs with the most efficient combined heat and power generation of electricity, less heat discharge in cooling towers and increase the throughput of heating mains . So, in the works of A.B. Bogdanov, a characteristic of the relative increase in fuel for heat supply from the steam turbine T-185/215 of Omsk CHPP-5 is given and it is shown that the increase in conventional fuel consumption for an increase in heat load is 30-50 kg/Gcal, depending on the temperature of the network water and on the electrical load of the turbine, which is confirmed by direct measurements. That. with a constant electrical load, the additional fuel consumption at a CHPP for heat supply is 3-5 times lower than from hot water boilers.
The most effective application in climate systems is the use of HPI "water - air", i.e. not heating water for the heating system, but obtaining air of the required parameters - this is a real opportunity to create comfortable conditions even with unstable operation of the heating network, where temperature and hydraulic conditions are not maintained, using the amount of heat from the source and converting it into the quality of heat supply. At the same time, such a system solves the issue of air cooling in the summer, which is especially important for modern office and cultural centers, elite residential complexes, hotels, where a completely natural requirement - air conditioning - is often extremely inefficiently provided by the spontaneous equipping of premises with split systems with external units. on the facade of the building. For objects with the need to simultaneously heat and cool the air, a ring heating and air conditioning system is used - a solution known in Russia from 15 years of experience in operating the Iris Congress Hotel in Moscow, such solutions are currently being implemented at other facilities. At the heart of the ring system is a circulation circuit with a water temperature of 20-30 °C; consumers have installed water-to-air heat pumps that cool the air in the room and pump its heat into a common water circuit or from a common (water) circuit pump heat into the room, heating the air. The water temperature in the water circuit is maintained within a certain range by known methods - this is the removal of excess heat in summer with the help of a cooling tower, heating water in winter with network water. The design capacity of both the cooling tower and the heat source is significantly less than would be required with traditional air conditioning and heat supply systems, and the construction of buildings equipped with such systems is less dependent on the capabilities of the heat transport system.
Instead of a conclusion
To date, we can draw an unambiguous conclusion - the euphoria that was on initial stage the introduction of apartment heating systems in multi-apartment residential buildings is no longer there. Apartment heating systems were installed because the pace of construction was quite intensive, and there was the possibility of introducing new projects of this kind (although perhaps not always deliberately). Now there has not been a complete rejection of these systems, there is an understanding of the pros and cons of both autonomous devices and DH systems.
It is necessary to make maximum use of the available possibilities of heating
systems of large cities, develop them, including measures of state regulation to ensure the commercial efficiency of district heating.
It is quite possible to predict and neutralize imbalances in energy consumption within a metropolis with an integrated territorial approach to the urban economy as a single life support mechanism, if you do not see in it only sectoral structures and interests, and do not allocate and privatize private isolated plots for profit, without maintaining a state of full working capacity and proper technological upgrading. Obviously, no private solutions for autonomous power supply will save the situation. It is necessary to increase the sustainability of energy infrastructures with the help of a variety of energy technology units and systems. The interconnection and coordination of modes of generation and consumption of energy resources does not in any way imply the rejection of unified urban life support systems, on the contrary, they are joined with possible autonomous units in such a way as to ensure maximum efficiency energy use, reliability and environmental safety.
Literature
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Federal Law No. 261-FZ "On Energy Saving and Improving Energy Efficiency and on Amendments to Certain Legislative Acts" Russian Federation» provides for a significant reduction in energy consumption by heating and ventilation systems of residential buildings.
According to the draft order of the Ministry of Regional Development of the Russian Federation, it is planned to introduce normalized levels of specific annual consumption of thermal energy for heating and ventilation. As a base level of energy consumption, indicators are introduced that correspond to building projects completed in accordance with the standards of 2008 before the federal law was put into effect.
Thus, by Decree of the Government of Moscow No. 900-PP, the specific energy consumption for heating, hot water supply, lighting and operation of general building engineering equipment in multi-apartment buildings residential buildings set from October 1, 2010 at the level of 160 kWh / m 2 year, from January 1, 2016 it is planned to reduce the figure to 130 kWh / m 2 year, and from January 1, 2020 - to 86 kWh / m 2 year. The share of heating and ventilation in 2010 accounts for approximately 25-30%, or 40-50 kWh/m 2 year. As of July 1, 2010, the standard in Moscow was 215 kWh/m 2 ·year, of which 90-95 kWh/m 2 ·year were for heating and ventilation.
Improving the energy efficiency of buildings can be achieved by increasing the level of thermal protection of the building envelope and improving heating and ventilation systems.
In basic terms, the distribution of heat energy consumption in a typical multi-storey building is carried out approximately equally between transmission heat losses (50-55%) and ventilation (45-50%).
Approximate distribution of the annual heat balance for heating and ventilation:
- transmission heat losses - 63-65 kWh/m 2 year;
- ventilation air heating - 58-60 kWh/m 2 year;
- internal heat generation and insolation - 25-30 kWh/m 2 year.
Is it possible to achieve standards only by increasing the level of thermal protection of the building fences?
With the introduction of energy efficiency requirements, the Moscow government prescribes an increase in the heat transfer resistance of building fences to the level of October 1, 2010 for walls from 3.5 to 4.0 deg m 2 / W, for windows from 1.8 to 1.0 deg m 2 / Tue Taking into account these requirements, transmission heat losses will decrease to 50-55 kWh/m 2 ·year, and the overall energy efficiency indicator - up to 80-85 kWh/m 2 ·year.
These indicators of specific heat consumption are higher minimum requirements. Therefore, the problem of energy efficiency of residential buildings is not solved only by thermal protection. In addition, the attitude of specialists to a significant increase in the requirements for resistance to heat transfer of enclosing structures is ambiguous.
It should be noted that the practice of mass construction of residential buildings included modern systems heating using room thermostats, balancing valves and weather-dependent automation of heat points.
The situation is more complicated with ventilation systems. So far, natural ventilation systems have been used in mass construction. The use of wall and window self-regulating supply dampers is a means of limiting excess air exchange and does not fundamentally solve the problem of energy saving.
In world practice, mechanical ventilation systems with exhaust air heat recovery are widely used. The energy efficiency of heat recovery units is up to 65% for plate heat exchangers and up to 85% for rotary ones.
When using these systems in Moscow, the reduction of annual heat consumption for heating and ventilation to the base level can be 38-50 kWh/m 2 year, which allows reducing the total specific heat consumption to 50-60 kWh/m 2 year without changing the basic level of thermal protection of fences and ensure a 40% reduction in the energy intensity of heating and ventilation systems, provided for from 2020.
The problem lies in the economic efficiency of mechanical ventilation systems with exhaust air heat exchangers and the need for their qualified maintenance. Imported apartment installations are quite expensive, and their cost in turnkey installation costs 60-80 thousand rubles. for one apartment. With current electricity tariffs and maintenance costs, they pay off in 15-20 years, which is a serious obstacle to their use in the mass construction of affordable housing. The acceptable cost of installation for economy-class housing should be recognized as 20-25 thousand rubles.
Apartment ventilation systems with plate heat exchanger
Within the framework of the federal target program of the Ministry of Education and Science of the Russian Federation, MIKTERM LLC conducted research and developed a laboratory sample of an energy-saving apartment ventilation system (ESV) with a plate heat exchanger. The sample is designed as a budget installation option for economy-class residential buildings.
When creating a budget apartment installation that meets sanitary standards, the following technical solutions were adopted, which made it possible to reduce the cost of ESP:
- the heat exchanger is made of cellular polycarbonate plates;
- electric heater excluded N= 500 W;
- due to the low aerodynamic resistance of the heat exchanger, the energy consumption is 46 W;
- simple automation was used to ensure reliable operation of the plant.
The calculation of the cost of the developed ESP is given in the table.
Unlike imported analogues, the unit does not use electric heaters either for frost protection or for air reheating. The installation during tests showed an energy efficiency of at least 65%.
Frost protection is solved as follows. When the heat exchanger freezes, an increase in the aerodynamic resistance of the exhaust duct occurs, which is recorded by a pressure sensor that gives the command to short-term decrease in the supply air flow until normal pressure is restored.
On fig. 1 shows a graph of the change in the supply air temperature depending on the outdoor air temperature at different supply air flow rates. The exhaust air flow is constant and equal to 150 m 3 /h.
Pilot project of an energy efficient residential building
On the basis of an apartment installation with a heat recovery unit, a pilot project was developed for an energy-efficient residential building in Northern Izmailovo in Moscow. The project provides technical requirements for apartment installations supply and exhaust ventilation with heat exchangers. For the innovative installation, the characteristics of MIKTERM LLC are given.
The units are designed for energy-efficient balanced ventilation and creating a comfortable climate in residential premises up to 120 m2. Apartment-by-apartment ventilation with mechanical stimulation and exhaust air heat recovery for supply air heating is provided. Supply and exhaust units are installed autonomously in the corridors of apartments and are equipped with filters, plate heat exchanger and fans. The unit is equipped with automation equipment and a control panel that allows you to adjust the air capacity of the unit.
Passing through the ventilation unit with a plate heat exchanger, the exhaust air heats the supply air to a temperature t= +4.0 ˚С (at outside air temperature t= -28 ˚С). Compensation for heat deficiency for supply air heating is carried out by heating devices.
Outside air is taken from the loggia of this apartment, the hood, combined within one apartment from bathrooms, bathrooms and kitchens, after the utilizer is discharged into the exhaust duct via satellite and is thrown out within the technical floor. If necessary, condensate is drained from the heat exchanger into a sewer riser equipped with an HL 21 drip funnel with an odor-locking device. The stand is located in the bathrooms.
Supply and exhaust air flow control is carried out by means of one control panel. The unit can be switched from normal operation with heat recovery to summer operation without heat recovery. Switching is carried out using a damper located in the heat exchanger. Ventilation of the technical floor is carried out through deflectors. According to the test results, the efficiency of using a plant with a heat exchanger can reach 67%.
Estimated heat consumption for supply air heating per apartment when direct-flow ventilation is used is:
Q = L· C·γ·∆ t, Q\u003d 110 × 1.2 × 0.24 × 1.163 × (20 - (-28)) \u003d 1800 watts.
When using a plate heat exchanger, the heat consumption for reheating the supply air
Q\u003d 110 × 1.2 × 0.24 × × 1.163 × (20 - 4) \u003d 590 watts.
The heat savings per apartment at the calculated outdoor temperature is 1210 W. The total heat savings in the house is
1210 × 153 = 185130 W.
The volume of supply air is taken to compensate for the exhaust from the premises of the bathroom, bath, kitchen. No exhaust duct for connection kitchen equipment(exhaust hood from the stove works for recirculation). The inflow is diluted through sound-absorbing air ducts to the living rooms. Stitching provided ventilation unit in apartment corridors with a building structure with hatches for maintenance and an exhaust duct from the ventilation unit to the exhaust shaft. The maintenance warehouse has four redundant fans. On fig. 2 shows a schematic diagram of the ventilation of an apartment building, and in fig. 3 - plan of a typical floor with the placement of ventilation units.
Additional costs for the installation of apartment ventilation with exhaust air heat recovery for the whole house are estimated at 3 million rubles. The annual heat savings will be 19 800 kWh. Taking into account changes in existing tariffs for thermal energy, a simple payback period will be about 8 years.
Literature
- Decree of the Government of Moscow No. 900-PP dated October 5, 2010 “On improving the energy efficiency of residential, social and public and business buildings in Moscow and amending the Decree of the Government of Moscow dated June 9, 2009 No. 536-PP”.
- Livchak V.I. Improving the energy efficiency of buildings // Energy saving. - 2012. - No. 6.
- Gagarin V.G. Macroeconomic aspects of substantiation of energy-saving measures while increasing the thermal protection of enclosing structures of buildings // Stroitelnye materialy.- 2010.- March.
- Gagarin V.G., Kozlov V.V. On the regulation of heat loss through the shell of a building // Architecture and construction. - 2010. - No. 3.
- S.F. Serov, LLC "MIKTERM", [email protected]
- A.Yu. Milovanov, NPO TERMEK LLC
- link to the original source http://www.abok.ru/for_spec/articles.php?nid=5469
