1.1 Selecting the type of heat transfer fluids

2. Selection and justification of the heat supply system and its composition

3. Construction of graphs of changes in heat supply. Annual fuel equivalent.

4. The choice of the method of regulation. Calculation of the temperature graph

4.1 Choice of the method of heat supply control

4.2 Calculation of water temperatures in heating systems with dependent connection

4.2.1 Water temperature in the supply line of the heating network, о С

4.2.2 Temperature of water leaving the heating system

4.2.3 Water temperature after mixing device (elevator)

4.3 Readjustment of the hot water supply system

4.4 Calculation of water consumption from the heating network for ventilation and water temperature after ventilation systems

4.5 Determination of the flow rate of network water in the supply and return pipelines of the water heating network

4.5.1 Water flow in the heating system

4.5.2 Water consumption in the ventilation system

4.5.3 Water consumption in the DHW system.

4.5.4 Weighted average temperature in the return line of the heating network.

5. Construction of charts of network water consumption by objects and in total

6. The choice of type and method of laying the heating network

7. Hydraulic calculation of the heating network. Plotting a piezometric graph

7.1. Hydraulic calculation of the water heating network

7.2 Hydraulic calculation of branched heating networks

7.2.1 Calculation of the section of the main highway I - TK

7.2.2 Calculation of the branch TK - Zh1.

7.2.3 Calculation of throttle washers on the branches of the heating network

7.3 Plotting a piezometric graph

7.4 Selection of pumps

7.4.1 Selecting the mains pump

7.4.2 Selecting a charging pump

8. Thermal calculation of heating networks. Calculation of the thickness of the insulating layer

8.1 Basic network parameters

8.2 Calculation of the thickness of the insulating layer

8.3 Calculation of heat losses

9. Thermal and hydraulic calculations of the steam pipeline

9.1 Hydraulic calculation of the steam line

9.2 Calculation of the thickness of the insulating layer of the steam pipe

10. Calculation of the thermal circuit of the heat supply source. Selection of main and auxiliary equipment.

10.1 Source data table

11. Selection of basic equipment

11.1 Selection of steam boilers

11.2 Selection of deaerators

11.3 Selection of feed pumps

12. Thermal calculation of heating water heaters

12.1 Steam / water heater

12.2 Sizing the condensate cooler

13. Technical and economic indicators of the heat supply system

Conclusion

Bibliography

introduction

Industrial enterprises and the housing and utilities sector consume a huge amount of heat for technological needs, ventilation, heating and hot water supply. Thermal energy in the form of steam and hot water is generated by combined heat and power plants, industrial and district heating boilers.

The transfer of enterprises to full cost accounting and self-financing, the planned increase in fuel prices and the transition of many enterprises to two- and three-shift work require serious restructuring in the design and operation of production and heating boiler houses.

Industrial and heating boiler houses must ensure uninterrupted and high-quality heat supply to enterprises and consumers of the housing and communal sector. Improving the reliability and efficiency of heat supply largely depends on the quality of the boiler units and is rational. the designed heating scheme of the boiler room. Leading design institutes have developed and are improving rational heating schemes and standard designs for production and heating boiler houses.

The purpose of this course project is to acquire skills and familiarize yourself with the methods for calculating the heat supply to consumers, in a particular case - calculating the heat supply of two residential areas and an industrial enterprise from a heat supply source. The goal was also set to get acquainted with the existing state standards, and building codes and regulations related to heat supply, familiarization with the typical equipment of heating networks and boiler houses.

In this course project, graphs of changes in the heat supply to each object will be built, the annual supply of equivalent fuel for heat supply is determined. Calculation will be made and temperature graphs will be built, as well as graphs of network water consumption by objects and in total. A hydraulic calculation of heating networks was carried out, a piezometric graph was built, pumps were selected, a thermal calculation of heating networks was made, the thickness of an insulating coating was calculated. The flow rate, pressure and temperature of the steam generated at the heat supply source have been determined. The main equipment is selected, the heating water heater is calculated.

The project is of an educational nature, therefore, it provides for the calculation of the heating scheme of the boiler house only in the maximum winter mode. The rest of the modes will also be affected, but indirectly.

1. Selection of the type of coolants and their parameters

1.1 Selecting the type of heat transfer fluids

The choice of heat carrier and heat supply system is determined by technical and economic considerations and depends mainly on the type of heat source and the type of heat load.

In our course project, there are three heat supply objects: an industrial enterprise and 2 residential areas.

Using the recommendations, for heating, ventilation and hot water supply of residential and public buildings, we accept the water heat supply system. This is because water has a number of advantages over steam, namely:

a) higher efficiency of the heat supply system due to the absence of condensate and steam losses in subscriber units, which occur in steam systems;

b) increased storage capacity of the water system.

For an industrial enterprise, we use steam as a single heat carrier for technological processes, heating, ventilation and hot water supply.

1.2 Choice of parameters of heat carriers

Process steam parameters are determined according to consumer requirements and taking into account pressure and heat losses in heating networks.

Due to the fact that there is no data on hydraulic and heat losses in the networks, based on the operating and design experience, we take the specific pressure losses and the decrease in the temperature of the coolant due to heat losses in the steam pipeline, respectively

Taking into account the above, the temperature of the steam at the consumer's inlet is, 0 С:

According to the saturation pressure of steam at the obtained steam temperature at the consumer

The steam pressure at the source outlet, taking into account the accepted hydraulic losses, will be, MPa:

Steam saturation temperature at pressure

where 0 С

So, finally accepted

In the heat supply system, water is taken as a heat carrier to meet the loads of heating, ventilation and hot water supply. The choice is due to the fact that in residential and public buildings in district heating systems, in order to comply with sanitary standards, it is necessary to take water as a heat carrier. Application for enterprises as a heat carrier of steam for technological processes, heating, ventilation and hot water supply is allowed with a feasibility study. Due to the lack of data for conducting a feasibility study, and the absence of the need for this (not provided for by the assignment), hot water is finally taken as a heat carrier for heating, ventilation and hot water supply of residential areas and an industrial enterprise.

4.1 The composition of the sections of the design documentation and the requirements for their content are given in.

4.2 Equipment and materials used in the design, in cases established by documents in the field of standardization, must have certificates of compliance with the requirements of Russian norms and standards, as well as a permit from Rostekhnadzor for their use.

4.3 When designing boiler rooms with steam and hot water boilers with a steam pressure of more than 0.07 MPa (0.7 kgf / cm 2) and with a water temperature of more than 115 ° C, it is necessary to comply with the relevant rules and regulations in the field of industrial safety, as well as documents in the field standardization.

4.4 The design of new and reconstructed boiler houses should be carried out in accordance with the heat supply schemes developed and agreed in the established manner, or with the justification of investments in construction adopted in the schemes and projects of district planning, master plans of cities, townships and rural settlements, planning projects for residential, industrial and other functional areas or individual objects listed in.

4.5 Design of boiler houses for which the type of fuel has not been determined in accordance with the established procedure is not allowed. The type of fuel and its classification (main, emergency, if necessary) is determined in agreement with the regional authorized authorities. The quantity and method of delivery must be agreed with the fuel supplying organizations.

4.6 Boiler houses for their intended purpose in the heat supply system are subdivided into:

• central in the district heating system;
• peak in the centralized and decentralized heat supply system based on combined heat and power generation;
• autonomous systems of decentralized heat supply.

4.7 by purpose are subdivided into:

• heating - to provide heat energy to heating, ventilation, air conditioning and hot water supply systems;
• heating and production - to provide heat energy to heating, ventilation, air conditioning, hot water supply, process heat supply systems;
• industrial - to provide thermal energy to technological heat supply systems.

4.8 Boiler houses are subdivided into boiler houses of the first and second categories according to the reliability of heat energy supply to consumers (according to SP 74.13330).

• boiler houses, which are the only source of thermal energy of the heat supply system;
• boiler houses providing heat energy to consumers of the first and second categories who do not have individual reserve sources of heat energy. Lists of consumers by category are established in the design assignment.

4.9 In boiler houses with steam and steam-water boilers with a total installed thermal power of more than 10 MW, in order to increase reliability and energy efficiency, it is recommended to install low-power steam turbine generators with a voltage of 0.4 kV with steam backpressure turbines in feasibility studies to cover the electrical loads of the boiler houses' auxiliary needs or the enterprises in which they are located. The spent steam after the turbines can be used: for technological steam supply to consumers, for heating water in heat supply systems, for the auxiliary needs of the boiler house.

The design of such installations should be carried out in accordance with.

In hot water boilers operating on liquid and gaseous fuels, it is allowed to use gas turbine or diesel installations for these purposes.

When designing an electric power superstructure for generating electrical energy for the boiler house's own needs and / or transferring it to the network, it should be carried out in accordance with,. If the requirements for reliability and safety established by regulatory documents are not enough for the development of project documentation, or such requirements are not established, special technical conditions should be developed and approved in the prescribed manner.

4.10 For heat supply of buildings and structures from block-modular boiler houses, it should be possible to operate the equipment of the boiler room without permanently present personnel.

4.11 The estimated thermal power of the boiler house is determined as the sum of the maximum hourly consumption of thermal energy for heating, ventilation and air conditioning, the average hourly consumption of thermal energy for hot water supply and the consumption of thermal energy for technological purposes. When determining the estimated thermal power of the boiler house, the consumption of heat energy for the auxiliary needs of the boiler house, losses in the boiler house and in the heating networks, taking into account the energy efficiency of the system, should also be taken into account.

4.12 Estimated heat energy consumption for technological purposes should be taken according to the design assignment. In this case, the possibility of a mismatch in the maximum consumption of thermal energy for individual consumers should be taken into account.

4.13 Estimated hourly consumption of heat energy for heating, ventilation, air conditioning and hot water supply should be taken according to the design assignment, in the absence of such data - determined according to SP 74.13330, as well as according to recommendations.

4.14 The number and capacity of boilers installed in the boiler room should be selected, ensuring:

• design capacity (heat output of the boiler house in accordance with 4.11);
• stable operation of boilers at the minimum permissible load during the warm season.

In case of failure of the largest boiler in terms of productivity in the boiler houses of the first category, the remaining boilers must provide the supply of heat energy to consumers of the first category:

• for process heat supply and ventilation systems - in the amount determined by the minimum permissible loads (regardless of the outside temperature);
• for heating and hot water supply - in the amount determined by the regime of the coldest month.

In case of failure of one boiler, regardless of the category of the boiler room, the amount of heat supplied to consumers of the second category must be provided in accordance with the requirements of SP 74.13330.

The number of boilers installed in boiler rooms and their performance should be determined on the basis of technical and economic calculations.

Boiler rooms should provide for the installation of at least two boilers; in industrial boiler houses of the second category - installation of one boiler.

4.15 In boiler house projects, boilers, economizers, air heaters, backpressure turbines, gas turbine and gas piston plants with 0.4 kV generators, ash collectors and other equipment in modular transportable design of full factory and installation readiness should be used.

4.16 Projects of auxiliary equipment blocks with pipelines, automatic control, regulation, signaling systems and electrical equipment of increased factory readiness are developed according to the order and assignments of the installation organizations.

4.17 Open installation of equipment in different climatic zones is possible if it is allowed by the instructions of the manufacturers and meets the noise characteristics requirements in SP 51.13330 and.

4.18 The layout and placement of the technological equipment of the boiler room should ensure:

• conditions for the mechanization of repair work;
• the possibility of using floor lifting and transport mechanisms and devices during repair work.

For the repair of equipment units and pipelines weighing more than 50 kg, inventory lifting devices should be provided, as a rule. If it is impossible to use inventory lifting devices, stationary lifting devices (hoists, telphers, overhead and bridge cranes) should be provided.

4.19 In boiler rooms, according to the design assignment, repair areas or premises for repair work should be provided. In this case, one should take into account the possibility of performing repair work on the specified equipment by the relevant services of industrial enterprises or specialized organizations.

4.20 The main technical solutions adopted in the project should provide:

• reliability and safety of equipment operation;
• maximum energy efficiency of the boiler room;
• economically justified costs of construction, operation and repair;
• labor protection requirements;
• required sanitary and living conditions for operating and maintenance personnel;
• environmental protection requirements.

4.21 Thermal insulation of boiler equipment, pipelines, fittings, gas ducts, air ducts and dust pipelines should be provided taking into account the requirements of SP 60.13330 and SP 61.13330.

In the same section:

FOREWORD

“Gas is safe only if it is properly operated

gas boiler room equipment ".

The operator's manual provides basic information about a hot-water boiler house operating on gaseous (liquid) fuel, considers the schematic diagrams of boiler houses and heat supply systems for industrial facilities. The manual also:

• • basic information from heat engineering, hydraulics, aerodynamics is presented;

• • provides information on energy fuel and the organization of their combustion;

• • highlighted the issues of water preparation for hot water boilers and heating networks;

• • the device of hot water boilers and auxiliary equipment of gasified boiler houses is considered;

• • gas supply schemes for boiler houses are presented;

• • a description of a number of instrumentation and automatic control schemes and safety automation is given;

• • great attention was paid to the issues of operation of boiler units and auxiliary equipment;

• • issues on preventing accidents of boilers and auxiliary equipment, on providing first aid to victims of an accident were considered;

• provides basic information on the organization of efficient use of heat and power resources.

This operator's manual is intended for retraining, training in a related profession and advanced training for operators of gas boiler houses, and can also be useful: for students and students in the specialty "Heat and gas supply" and operational dispatching personnel when organizing a dispatch service for the operation of automated boiler houses. To a greater extent, the material is presented for hot water boiler houses with a capacity of up to 5 Gcal with gas-tube boilers of the "Turboterm" type.

By subscribing to the Set of Educational and Methodological Materials for the Boiler House Operator, You will receive the book “Definition of Knowledge. Test for the boiler room operator ”. And in the future you will receive from me both free and paid information materials.

INTRODUCTION

Modern boiler technology of low and medium productivity is developing in the following directions:

• increasing energy efficiency by reducing heat losses in every possible way and making the most of the energy potential of the fuel;
• reducing the size of the boiler unit due to the intensification of the fuel combustion process and heat exchange in the furnace and heating surfaces;
• reduction of harmful toxic emissions (CO, NO x, SO v);
• improving the reliability of the boiler unit.

New combustion technology is being implemented, for example, in pulsating boilers. The combustion chamber of such a boiler is an acoustic system with a high degree of turbulence of flue gases. In the combustion chamber of boilers with pulsating combustion, there are no burners, and therefore no torch. The supply of gas and air is carried out intermittently with a frequency of about 50 times per second through special pulsating valves, and the combustion process takes place in the entire furnace volume. When fuel is burned in the furnace, the pressure rises, the rate of combustion products increases, which leads to a significant intensification of the heat exchange process, the possibility of reducing the size and weight of the boiler, and the absence of the need for bulky and expensive chimneys. The operation of such boilers is characterized by low CO and N0 x emissions. The efficiency of such boilers reaches 96 %.

Vacuum hot water boiler of the Japanese company Takuma is a sealed container filled with a certain amount of well-purified water. The boiler furnace is a flame tube located below the liquid level. Above the water level in the steam space, two heat exchangers are installed, one of which is included in the heating circuit, and the other works in the hot water supply system. Due to a small vacuum, automatically maintained inside the boiler, water boils in it at a temperature below 100 o C. After evaporating, it condenses on the heat exchangers and then flows back. Purified water is not removed from the unit anywhere, and it is not difficult to provide the required amount. Thus, the problem of chemical preparation of boiler water was removed, the quality of which is an indispensable condition for reliable and long-term operation of the boiler unit.

Heating boilers of the American company Teledyne Laars are water-tube installations with a horizontal heat exchanger made of finned copper pipes. A feature of such boilers, called hydronic boilers, is the ability to use them on untreated network water. These boilers provide for a high speed of water flow through the heat exchanger (more than 2 m / s). Thus, if the water corrodes the equipment, the resulting particles will be deposited anywhere but in the boiler heat exchanger. In the case of hard water, a fast flow will reduce or prevent scale build-up. The need for high speed led the developers to the decision to minimize the volume of the boiler water part as much as possible. Otherwise, a too powerful circulation pump is needed, which consumes a large amount of electricity. Recently, products of a large number of foreign firms and joint foreign and Russian enterprises, developing a wide variety of boiler equipment, have appeared on the Russian market.

Fig. 1. Hot water boiler of the Unitat brand of the international company LOOS

1 - burner; 2 - door; 3 - peephole; 4 - thermal insulation; 5 - gas tube heating surface; 6 - hatch into the boiler water space; 7- fire tube (firebox); 8 - branch pipe for supplying water to the boiler; 9 - hot water outlet; 10 - flue gas duct; 11 - viewing window; 12 - drainage pipeline; 13 - support frame

Modern hot water and steam boilers of small and medium power are often performed as fire-tube or flame-gas-tube boilers. These boilers are distinguished by high efficiency, low emissions of toxic gases, compactness, high degree of automation, ease of operation and reliability. In fig. 1 shows a combined fire and gas-tube hot water boiler of the Unimat brand of the international company LOOS. The boiler has a firebox, made in the form of a flame tube 7, washed from the sides with water. In the front end of the flame tube there is a hinged door 2 with two-layer thermal insulation 4. The burner 1 is installed in the door. The combustion products from the flame tube enter the convective gas tube surface 5, in which they make a two-way movement, and then leave the boiler through the gas duct 10. Water is supplied to the boiler through pipe 8, and hot water is removed through pipe 9. The outer surfaces of the boiler are thermally insulated 4. To observe the flame, a peephole is installed in the door 3. Inspection of the state of the outer part of the gas tube surface can be done through hatch 6, and the end part of the body - through the inspection window 11. Drain pipe 12 is provided to drain water from the boiler. The boiler is installed on a support frame 13.

In order to assess the efficient use of energy resources and reduce consumer costs for fuel and energy supply, the Law “On Energy Saving” provides for energy audits. Based on the results of these surveys, measures are being developed to improve the heat and power facilities of the enterprise. These activities are as follows:

• • replacement of heat and power equipment (boilers) with more modern ones;

• • hydraulic calculation of the heating network;

• • adjustment of hydraulic modes of heat consumption objects;

• • rationing of heat consumption;

• • elimination of defects in enclosing structures and the introduction of energy-efficient structures;

• retraining, advanced training and material incentives for personnel for the effective use of fuel and energy resources.

For enterprises with their own heat sources, training of qualified boiler operators is required. Persons trained, certified and having a certificate for the right to service the boilers may be allowed to service the boilers. This operator's training manual serves exactly to solve these problems.

CHAPTER 1. PRINCIPAL DIAGRAMS OF BOILER AND HEAT SUPPLY SYSTEMS

1.1. Basic thermal diagram of a hot water boiler house operating on gas fuel

In fig. 1.1 shows a basic thermal diagram of a hot water boiler house operating on a closed hot water supply system. The main advantage of this scheme is the relatively low productivity of the water treatment plant and feed pumps, the disadvantage is the rise in the cost of equipment for hot water supply subscribers (the need to install heat exchangers in which heat is transferred from the network water to the water used for hot water supply). Hot water boilers operate reliably only when maintaining a constant flow rate of water passing through them within the specified limits, regardless of fluctuations in the consumer's heat load. Therefore, in the thermal circuits of hot water boilers, the regulation of the supply of heat energy to the network according to a high-quality schedule, i.e. by changing the temperature of the water leaving the boiler.

To ensure the design temperature of water at the entrance to the heating network, the scheme provides for the possibility of mixing the required amount of return network water (G per) to the water leaving the boilers through the bypass line. To eliminate low-temperature corrosion of the tail heating surfaces of the boiler to the return network water at its temperature less than 60 ° C when operating on natural gas and less than 70-90 ° C when operating on low and high-sulfur fuel oil, hot water leaving the boiler is mixed using a recirculation pump to the return water supply.

Fig 1.1. Basic thermal diagram of the boiler room. Single-circuit, dependent with recirculation pumps

1 - hot water boiler; 2-5 - pumps for network, recirculation, raw and make-up water; 6- make-up water tank; 7, 8 - heaters for raw and chemically purified water; 9, 11 - make-up water and vapor coolers; 10 - deaerator; 12 - installation for chemical water treatment.

Figure 1.2. Basic thermal diagram of the boiler room. Double-circuit, dependent with hydraulic adapter

1 - hot water boiler; 2-boiler circulation pump; 3- network heating pump; 4- network ventilation pump; 5-pump for domestic hot water supply; 6- DHW circulation pump; 7-water-to-water heater for hot water supply; 8-mud filter; 9-reagent water treatment; 10-hydraulic adapter; 11-membrane tank.

1.2. Schematic diagrams of heating networks. Open and closed heating networks

Water heat supply systems are divided into closed and open. In closed systems, the water circulating in the heating network is used only as a heat carrier, but is not taken from the network. In open systems, the water circulating in the heating network is used as a heat carrier and is partially or completely taken from the network for hot water supply and technological purposes.

The main advantages and disadvantages of closed water heat supply systems:

• • stable quality of hot water supplied to subscriber installations, which does not differ from the quality of tap water;

• simplicity of sanitary control of local hot water supply installations and control of the density of the heating system;

• • the complexity of the equipment and operation of hot water supply subscribers;

• • corrosion of local hot water installations due to the ingress of non-deaerated tap water into them;

• • scale precipitation in water-water heaters and pipelines of local hot water supply installations with tap water with increased carbonate (temporary) hardness (Zh to ≥ 5 mg-eq / kg);

• with a certain quality of tap water, it is necessary, with closed heat supply systems, to take measures to increase the anticorrosive resistance of local hot water supply installations or to install special devices at subscriber inputs for deoxygenation or stabilization of tap water and for protection from sludge.

The main advantages and disadvantages of open water heat supply systems:

• • the possibility of using low-potential (at temperatures below 30-40 о С) thermal resources of the industry for hot water supply;

• • simplification and cheapening of subscriber inputs and increasing the durability of local hot water supply installations;

• the possibility of using single-pipe lines for transit heat;

• • complication and rise in the cost of station equipment due to the need to build water treatment plants and make-up devices designed to compensate for water consumption for hot water supply;

• • water treatment should provide clarification, softening, deaeration and bacteriological treatment of water;

• • instability of water supplied to the water intake, according to sanitary indicators;

• • complication of sanitary control over the heat supply system;

• complication of control of the tightness of the heat supply system.

1.3. Temperature graph for quality control of the heating load

There are four methods for regulating the heating load: qualitative, quantitative, qualitative-quantitative and intermittent (gaps). High-quality regulation consists in regulating the supply of heat by changing the temperature of hot water while maintaining a constant amount (flow) of water; quantitative - in the regulation of heat supply by changing the water flow rate at its constant temperature at the inlet to the controlled installation; qualitative and quantitative - in the regulation of heat supply by a simultaneous change in the flow rate and water temperature; intermittent, or, as it is commonly called, regulation by gaps - in the regulation of heat supply by periodically disconnecting heating installations from the heating network. The temperature schedule for high-quality control of heat supply for heating systems equipped with convective-radiant heating devices and connected to the heating network according to an elevator scheme is calculated based on the formulas:

T 3 = t int.r + 0.5 (T 3p - T 2p) * (t int.r - t n) / (t int.r - t n.r) + 0.5 * (T 3p + T 2p -2 * t int.r) * [(t int.r - t n) / (t int.r - t n.r)] 0.8. T 2 = T 3 - (T 3p - T 2p) * (t int.r - t n) / (t int.r - t n.r). T 1 = (1+ u) * T 3 - u * T 2

where T 1 is the temperature of the supply water in the supply line (hot water), o C; Т 2 - temperature of water entering the heating network from the heating system (return water), о С; T 3 is the temperature of the water entering the heating system, about C; t n - outside air temperature, about С; t vn - internal air temperature, about С; u is the mixing coefficient; the same designations with the index "p" refer to the design conditions. For heating systems equipped with convective-radiant heating devices and connected to the heating network directly, without an elevator, u = 0 and T 3 = T 1 should be taken. The temperature graph of the qualitative regulation of the heat load for the city of Tomsk is shown in Figure 1.3.

Regardless of the adopted method of central regulation, the water temperature in the supply pipe of the heating network must not be lower than the level determined by the conditions of hot water supply: for closed heat supply systems - not lower than 70 ° C, for open heat supply systems - not lower than 60 ° C. Water temperature in the supply pipeline looks like a broken line on the graph. At low temperatures t n< t н.и (где t н.и – наружная температура, соответствующая излому температурного графика) Т 1 определяется по законам принятого метода центрального регулирования. При t н >t n. and the water temperature in the supply pipeline is constant (T 1 = T 1i = const), and heating installations can be controlled both quantitatively and intermittently (local passes) method. The number of hours of daily operation of heating installations (systems) in this range of outdoor temperatures is determined by the formula:

n = 24 * (t int.r - t n) / (t int.r - t n.i)

Example: Determining temperatures T 1 and T 2 for plotting a temperature graph

T 1 = T 3 = 20 + 0.5 (95- 70) * (20 - (-11) / (20 - (-40) + 0.5 (95+ 70 -2 * 20) * [(20 - (-11) / (20 - (-40)] 0.8 = 63.1 o C. T 2 = 63.1 - (95- 70) * (95- 70) * (20 - (-11) = 49.7 o C

Example: Determination of the number of hours of daily operation of heating installations (systems) at the outdoor temperature range t n> t ni. The outside air temperature is equal to t n = -5 o C. In this case, the heating installation must work per day

n = 24 * (20 - (-5) / (20 - (-11) = 19.4 hours / day.

1.4. Piezometric graph of the heating network

Heads at various points of the heat supply system are determined using water pressure graphs (piezometric graphs), which take into account the mutual influence of various factors:

• • geodetic profile of the heating main;

• • pressure losses in the network;

• the height of the heat consumption system, etc.

The hydraulic modes of operation of the heating network are divided into dynamic (when the coolant is circulating) and static (when the coolant is at rest). In static mode, the head in the system is set 5 m above the mark of the highest water position in it and is depicted by a horizontal line. There is one static head line for the supply and return pipelines. The heads in both pipelines are equalized, since the pipelines are connected using heat consumption systems and mixing jumpers in the elevator units. The pressure lines in the dynamic mode for the supply and return pipelines are different. The slopes of the pressure lines are always directed along the course of the coolant and characterize the pressure losses in the pipelines, determined for each section according to the hydraulic calculation of the pipelines of the heating network. The choice of the position of the piezometric graph is based on the following conditions:

• • the pressure at any point in the return line must not exceed the permissible operating pressure in local systems. (no more than 6 kgf / cm 2);

• • the pressure in the return pipeline must ensure the filling of the upper devices of local heating systems;

• • the head in the return line, in order to avoid the formation of a vacuum, should not be lower than 5-10 m.w.;

• • the pressure on the suction side of the network pump should not be lower than 5 mWC;

• • the pressure at any point in the supply pipeline must be higher than the boiling pressure at the maximum (design) temperature of the coolant;

• the available head at the end point of the network must be equal to or greater than the calculated head loss at the subscriber input at the calculated flow of the coolant.

In most cases, when moving the piezometer up or down, it is not possible to establish such a hydraulic mode in which all connected local heating systems could be connected according to the simplest dependent circuit. In this case, you should focus on the installation at the inputs of consumers, first of all, back-pressure regulators, pumps on the lintel, on the return or supply lines of the input, or choose an independent connection with the installation of heating water-to-water heaters (boilers) at consumers. The piezometric graph of the heating network is shown in Figure 1.4.

List the main elements of the heating system. Give a definition of an open and closed heating network, name the advantages and disadvantages of these networks.

1. 1. Write on a separate sheet of the main equipment of your boiler room and its characteristics.

1. 1. What heating networks do you know about the device? What is the temperature schedule for your heating network?

1. 1. What is the purpose of the temperature graph? What determines the temperature of the break in the temperature graph?

1. 1. What is the purpose of the piezometric graph? What is the role of elevators, if any, in heating units?

1. On a separate sheet, list the features of the operation of each element of the heat supply system (boiler, heating network, heat consumer). Always consider these features in your work! The operator's manual, together with a set of test tasks, should become a reference book for the operator who respects his work.

A set of training materials for the boiler operator costs 760 rbl.He tested in training centers for the training of boiler room operators, the reviews are very good, both from students and teachers of Special Technologies. BUY

water and water vapor, in connection with which distinguish between water and steam heat supply systems. Water, as a heat carrier, is used from district boiler houses, mainly equipped with hot water boilers and through heating water heaters from steam boilers.

Water as a heat carrier has a number of advantages over steam. Some of these advantages are especially important when supplying heat from CHP plants. The latter include the possibility of transporting water over long distances without significant loss of its energy potential, i.e. its temperature (the drop in water temperature in large systems is less than 1 ° С per 1 km of track). The energy potential of steam - its pressure - decreases during transportation more significantly, averaging 0.1 - 0.15 MPa per 1 km of track. Thus, in water systems, the steam pressure in the extraction of turbines can be very low (from 0.06 to 0.2 MPa), while in steam systems it should be up to 1–1.5 MPa. An increase in the steam pressure in the turbine outlets leads to an increase in fuel consumption at the CHPP and a decrease in electricity generation based on heat consumption.

Other advantages of water as a heat carrier include the lower cost of connections to heating networks of local water heating systems, and with open systems, also local hot water supply systems. The advantages of water as a heat carrier is the possibility of central (at the heat source) regulation of heat supply to consumers by changing the water temperature. When using water, it is easy to operate - the consumers (inevitable when using steam) do not have condensate drains and pumping units for condensate return.

In fig. 4.1 is a schematic diagram of a hot water boiler house.

Rice. 4.1 Schematic diagram of a hot water boiler house: 1 - network pump; 2 - hot water boiler; 3 - circulation pump; 4 - heater for chemically purified water; 5 - raw water heater; 6 - vacuum deaerator; 7 - make-up pump; 8 - raw water pump; 9 - chemical water treatment; 10 - vapor cooler; 11 - water jet ejector; 12 - ejector supply tank; 13 - ejector pump.

Hot water boiler houses are often constructed in newly built areas before the commissioning of CHP and main heating networks from CHP to the indicated boiler houses. This prepares the heat load for the CHP plant, so that by the time the heating turbines are put into operation, their extractions are fully loaded. Hot water boilers are then used as peak or standby boilers. The main characteristics of steel hot water boilers are shown in table 4.1.

Table 4.1

5. Centralized heat supply from district boiler houses (steam).

6. District heating systems.

The complex of installations designed for the preparation, transportation and use of the heat carrier constitutes the centralized heat supply system.

Centralized heat supply systems provide consumers with heat of low and medium potential (up to 350 ° C), the production of which takes about 25% of all fuel produced in the country. Heat, as you know, is one of the types of energy, therefore, when solving the main issues of energy supply to individual objects and territorial regions, heat supply should be considered together with other energy supply systems - electricity and gas supply.

The heat supply system consists of the following main elements (engineering structures): a heat source, heating networks, subscriber inputs and local heat consumption systems.

Heat sources in centralized heat supply systems are either combined heat and power plants (CHP), which simultaneously produce both electricity and heat, or large boiler houses, sometimes referred to as district heating stations. Heat supply systems based on CHP plants are called "Heating".

The heat obtained in the source is transferred to one or another heat carrier (water, steam), which is transported through heating networks to the subscriber inputs of consumers. To transfer heat over long distances (more than 100 km), heat transport systems in a chemically bound state can be used.

Depending on the organization of the movement of the coolant, heat supply systems can be closed, semi-closed and open.

V closed systems the consumer uses only a part of the heat contained in the coolant, and the coolant itself, together with the remaining amount of heat, returns to the source, where it is replenished with heat again (two-pipe closed systems).

V semi-closed systems the consumer uses both a part of the heat supplied to it, and a part of the heat carrier itself, and the remaining amounts of the heat carrier and heat return to the source (two-pipe open systems).

V open systems, both the coolant itself and the heat contained in it are fully used by the consumer (one-pipe systems).

In centralized heat supply systems, the heat carrier is used water and water vapor, in connection with which distinguish between water and steam heat supply systems.

Water as a heat carrier has a number of advantages over steam. Some of these advantages are especially important when supplying heat from CHP plants. The latter include the possibility of transporting water over long distances without significant loss of its energy potential, i.e. its temperature, the decrease in water temperature in large systems is less than 1 ° C per 1 km of track). The energy potential of steam - its pressure - decreases during transportation more significantly, averaging 0.1 - 0.15 MPa per 1 km of track. Thus, in water systems, the steam pressure in the extraction of turbines can be very low (from 0.06 to 0.2 MPa), while in steam systems it should be up to 1–1.5 MPa. An increase in the steam pressure in the turbine outlets leads to an increase in fuel consumption at the CHPP and a decrease in electricity generation based on heat consumption.

In addition, water systems make it possible to keep the condensate of steam heating water clean at the CHP without the need for expensive and complex steam converters. With steam systems, the condensate returns from consumers often contaminated and far from completely (40–50%), which requires significant costs for its purification and preparation of additional boiler feed water.

Other advantages of water as a heat carrier include the lower cost of connections to heating networks of local water heating systems, and with open systems, also local hot water supply systems. The advantages of water as a heat carrier is the possibility of central (at the heat source) regulation of heat supply to consumers by changing the water temperature. When using water, it is easy to operate - the consumers (inevitable when using steam) do not have condensate drains and pumping units for condensate return.

7. Local and decentralized heat supply.

For decentralized heat supply systems, steam or hot water boilers are used, installed respectively in steam and hot water boilers. The choice of the type of boilers depends on the nature of heat consumers and the requirements for the type of heat carrier. Heat supply to residential and public buildings, as a rule, is carried out with the help of heated water. Industrial consumers require both heated water and steam.

The production and heating boiler house provides consumers with both steam with the required parameters and hot water. Steam boilers are installed in them, which are more reliable in operation, since their tail heating surfaces are not subject to such significant corrosion by flue gases as hot water ones.

A feature of hot water boilers is the absence of steam, and therefore the supply of industrial consumers is limited, and for degassing the make-up water, it is necessary to use vacuum deaerators, which are more difficult to operate than conventional atmospheric ones. However, the piping scheme for boilers in these boiler houses is much simpler than in steam ones. Due to the difficulty of preventing condensation from falling out on the tail heating surfaces from water vapor in the flue gases, the risk of failure of hot water boilers as a result of corrosion increases.

Quarterly and group heat generating installations designed to supply heat to one or several quarters, a group of residential buildings or single apartments, public buildings can act as sources for autonomous (decentralized) and local heat supply. These installations are, as a rule, heating.

Local heat supply is used in residential areas with a heat demand of not more than 2.5 MW for heating and hot water supply of small groups of residential and industrial buildings remote from the city, or as a temporary source of heat supply before the main one is commissioned in newly built areas. Boiler houses with local heat supply can be equipped with cast iron sectional, steel welded, vertical-horizontal-cylindrical steam and hot water boilers. Hot water boilers that have recently appeared on the market are especially promising.

With a sufficiently strong deterioration of the existing heating networks of centralized heat supply and the lack of necessary funding for their replacement, shorter heating networks of decentralized (autonomous) heat supply are more promising and more economical. The transition to autonomous heat supply became possible after the appearance on the market of highly efficient boilers of low heat output with an efficiency of at least 90%.

In the domestic boiler industry, effective similar boilers appeared, for example, those of the Borisoglebsk plant. These include boilers of the "Khoper" type (Fig. 7.1) installed in modular transportable automated boilers of the MT / 4,8 / type. Boiler houses also operate in automatic mode, since the "Khoper-80E" boiler is equipped with electrically controlled automatics (Fig.2.4).

Figure 7.1. General view of the "Khoper" boiler: 1 - peephole, 2 - draft sensor, 3 - tube, 4- boiler, 5 - automation unit, 6 - thermometer, 7- temperature sensor, 8 - igniter, 9 - burner, 10 - thermostat, - 11 - connector, 12 - burner valve, 13 - gas pipeline, 14 - igniter valve, 15 - drain plug, 16- igniter start, 17 - gas outlet, 18 - heating pipes, 19 - panels, 20 - door, 21 - cord with Euro plug.

Figure 7.2. shows the factory installation diagram of a water heater with a heating system.

Figure 7.2. Installation diagram of a water heater with a heating system: 1 - boiler, 2 - tap, 3 - deaerator, 3 - expansion tank fittings, 5 - radiator, 6 - expansion tank, 7 - water heater, 8 - safety valve, 9 - pump

The delivery set of Khoper boilers includes imported equipment: a circulation pump, a safety valve, an electromagnet, an automatic air valve, an expansion tank with fittings.

For modular boiler houses, boilers of the "KVa" type with a capacity of up to 2.5 MW are especially promising. They provide heat and hot water supply to several multi-storey buildings of the residential complex.

"KVA" automated hot water boiler unit, operating on low pressure natural gas under pressurization, is designed to heat water used in heating, hot water supply and ventilation systems. The boiler unit includes a hot water boiler with a heat recovery unit, a block automated gas burner with an automation system that provides regulation, control, parameter monitoring and emergency protection. It is equipped with an autonomous water supply system with shut-off valves and safety valves, which makes it easy to line up in a boiler room. The boiler unit has improved environmental characteristics: the content of nitrogen oxides in combustion products is reduced in comparison with regulatory requirements, the presence of carbon monoxide is practically close to zero.

The Flagman automated gas boiler belongs to the same type. It has two built-in finned tube heat exchangers, one of which can be connected to the heating system, the other to the hot water supply system. Both heat exchangers can be loaded together.

The prospect of the last two types of hot water boilers lies in the fact that they have a sufficiently low temperature of flue gases due to the use of heat exchangers or built-in heat exchangers with finned tubes. Such boilers have an efficiency of 3-4% higher compared to other types of boilers that do not have heat recovery units.

Air heating is also used. For this purpose, air heaters of the VRK-S type manufactured by Teploservis LLC, Kamensk-Shakhtinsky, Rostov Region, combined with a gaseous fuel furnace with a capacity of 0.45-1.0 MW, are used. For hot water supply, in this case, a flow-through gas water heater of the MORA-5510 type is installed. With local heat supply, boilers and boiler equipment are selected based on the requirements for the temperature and pressure of the coolant (heated water or steam). As a heat carrier for heating and hot water supply, as a rule, water is taken, and sometimes steam with a pressure of up to 0.17 MPa. A number of industrial consumers are provided with steam with a pressure of up to 0.9 MPa. Heating networks have a minimum length. The parameters of the coolant, as well as the thermal and hydraulic operating modes of heating networks, correspond to the operating mode of local heating and hot water supply systems.

The advantages of such heat supply are the low cost of heat supply sources and heating networks; ease of installation and maintenance; quick commissioning; a variety of boiler types with a wide range of heating capacities.

Decentralized consumers, which, due to the large distances from the CHPP, cannot be covered by centralized heat supply, must have a rational (efficient) heat supply that meets the modern technical level and comfort.

The scale of fuel consumption for heat supply is very large. At present, industrial, public and residential buildings are supplied with heat at about 40 + 50% from boiler houses, which is ineffective due to their low efficiency (in boiler houses, the combustion temperature of fuel is about 1500 ° C, and heat is supplied to the consumer at significantly lower temperatures (60 + 100 OS)).

Thus, the irrational use of fuel, when part of the heat escapes into the pipe, leads to the depletion of fuel and energy resources (FER).

An energy-saving measure is the development and implementation of decentralized heat supply systems with scattered autonomous heat sources.

Currently, the most expedient are decentralized heat supply systems based on non-traditional heat sources, such as: sun, wind, water.

Unconventional energy:

Heat supply based on heat pumps;

Heat supply based on autonomous water heat generators.

Prospects for the development of decentralized heat supply systems:

1. Decentralized heat supply systems do not require long heating mains, and therefore - large capital costs.

2. The use of decentralized heat supply systems can significantly reduce harmful emissions from fuel combustion into the atmosphere, which improves the environmental situation.

3. The use of heat pumps in decentralized heat supply systems for industrial and civilian facilities allows, in comparison with boiler houses, to save fuel in the amount of 6 + 8 kg of fuel equivalent. per 1 Gcal of generated heat, which is approximately 30 -: - 40%.

4. Decentralized systems based on TN are successfully used in many foreign countries (USA, Japan, Norway, Sweden, etc.). More than 30 companies are engaged in the manufacture of heat pumps.

5. An autonomous (decentralized) heat supply system based on a centrifugal water heat generator was installed in the OTT laboratory of the Department of PTS MPEI.

The system operates in automatic mode, maintaining the temperature of the water in the supply line in any given interval from 60 to 90 ° C.

The heat transformation ratio of the system is m = 1.5 -: - 2, and the efficiency is about 25%.

6. Further increase in the energy efficiency of decentralized heat supply systems requires scientific and technical research in order to determine the optimal operating modes.

8. The choice of heat carrier and heat supply system.

The choice of heat carrier and heat supply system is determined by technical and economic considerations and depends mainly on the type of heat source and the type of heat load. It is recommended to simplify the heating system as much as possible. The simpler the system, the cheaper it is to build and operate. The simplest solutions are provided by the use of a single coolant for all types of heat load.

If the district's heat load consists only of heating, ventilation and hot water supply, then heating is usually used two-pipe water system... In cases where, in addition to heating, ventilation and hot water supply, there is also a small technological load in the area that requires heat of increased potential, it is rational to use three-pipe water systems during heating. One of the supply lines of the system is used to satisfy the increased potential load.

In cases where when the main heat load of the district is the technological load of increased potential, and the seasonal heat load is small; usually steam.

When choosing a heat supply system and heat carrier parameters, technical and economic indicators for all elements are taken into account: heat source, network, subscriber installations. Energetically, water is more profitable than steam. The use of multi-stage heating of water at the CHPP allows to increase the specific combined production of electric and thermal energy, thereby increasing fuel economy. When using steam systems, the entire heat load is usually absorbed by the higher pressure exhaust steam, which reduces the specific combined electrical power generation.

The heat obtained in the source is transferred to one or another heat carrier (water, steam), which is transported through heating networks to the subscriber inputs of consumers.

Depending on the organization of the movement of the coolant, heat supply systems can be closed, semi-closed and open.

Depending on the number of heat pipelines in the heating network, water heat supply systems can be single-pipe, two-pipe, three-pipe, four-pipe and combined, if the number of pipes in the heating network does not remain constant.

In closed systems, the consumer uses only a part of the heat contained in the coolant, and the coolant itself, together with the remaining amount of heat, returns to the source, where it is replenished with heat (two-pipe closed systems). In semi-closed systems, the consumer uses both part of the heat supplied to him and part of the heat carrier itself, and the remaining amounts of the heat carrier and heat return to the source (two-pipe open systems). In open systems, both the heat carrier itself and the heat contained in it are fully used by the consumer (one-pipe systems).

At the subscriber inputs, heat (and in some cases the heat carrier itself) is transferred from heating networks to local heat consumption systems. At the same time, in most cases, the utilization of heat unused in local heating and ventilation systems is carried out to prepare water for hot water supply systems.

Local (subscriber) regulation of the amount and potential of heat transferred to local systems also takes place at the inputs, and the operation of these systems is monitored.

Depending on the accepted input scheme, i.e. depending on the adopted technology for transferring heat from heating networks to local systems, the estimated flow rates of the heat carrier in the heat supply system can vary by 1.5–2 times, which indicates a very significant effect of subscriber inputs on the economy of the entire heat supply system.

In centralized heat supply systems, water and steam are used as a heat carrier, in connection with which water and steam heat supply systems are distinguished.

Water as a heat carrier has a number of advantages over steam; some of these advantages are especially important when supplying heat from a CHP plant. The latter include the possibility of transporting water over long distances without significant loss of its energy potential, i.e. its temperature, the decrease in water temperature in large systems is less than 1 ° C per 1 km of track). The energy potential of steam - its pressure - decreases during transportation more significantly, averaging 0.1 - 015 MPa per 1 km of track. Thus, in water systems, the steam pressure in the extraction of turbines can be very low (from 0.06 to 0.2 MPa), while in steam systems it should be up to 1–1.5 MPa. An increase in the steam pressure in the turbine outlets leads to an increase in fuel consumption at the CHPP and a decrease in electricity generation based on heat consumption.

In addition, water systems make it possible to keep the condensate of steam heating water clean at the CHP without the need for expensive and complex steam converters. With steam systems, the condensate returns from consumers often contaminated and far from completely (40–50%), which requires significant costs for its purification and preparation of additional boiler feed water.

Other advantages of water as a heat carrier include: lower cost of connections to heating networks of local water heating systems, and with open systems also local hot water supply systems; the possibility of central (at the heat source) regulation of heat supply to consumers by changing the water temperature; ease of operation - the absence of the inevitable steam traps and condensate return pumping units for consumers.

Steam as a heat carrier, in turn, has certain advantages over water:

a) great versatility, which consists in the possibility of satisfying all types of heat consumption, including technological processes;

b) lower power consumption for moving the coolant (power consumption for the return of condensate in steam systems is very small compared to the cost of electricity for moving water in water systems);

c) the insignificance of the created hydrostatic pressure due to the low specific density of steam in comparison with the density of water.

The steadily pursued orientation in our country towards more economical heat supply systems and the indicated positive properties of water systems contribute to their widespread use in housing and communal services of cities and towns. To a lesser extent, water systems are used in industry, where more than 2/3 of the total heat demand is satisfied by steam. Since industrial heat consumption accounts for about 2/3 of the total heat consumption in the country, the share of steam in covering the total heat consumption remains very significant.

Depending on the number of heat pipelines in the heating network, water heat supply systems can be single-pipe, two-pipe, three-pipe, four-pipe and combined, if the number of pipes in the heating network does not remain constant. Simplified schematic diagrams of these systems are shown in Figure 8.1.

The most economical one-pipe (open-loop) systems (Figure 8.1.a) are advisable only when the average hourly consumption of network water supplied for heating and ventilation needs coincides with the average hourly consumption of water consumed for hot water supply. But for most regions of our country, except for the southernmost ones, the estimated costs of network water supplied for the needs of heating and ventilation turn out to be higher than the consumption of water consumed for hot water supply. With such an imbalance of the indicated costs, the water unused for hot water supply has to be sent to the drainage, which is very uneconomical. In this regard, the most widespread in our country are two-pipe heat supply systems: open (semi-closed) (Fig. 8.1., B) and closed (closed) (Fig. 8.1., C)

Figure 8.1. Schematic diagram of water heating systems

a — one-pipe (open), b — two-pipe open (semi-closed), c — two-pipe closed (closed), d-combined, e-three-pipe, e-four-pipe, 1-heat source, 2-supply pipe of the heating network, 3-subscriber input , 4 – ventilation air heater, 5 – subscriber heating heat exchanger, 6 –heater, 7 – local heating system pipelines, 8 – local hot water supply system, 9 – heating system return pipeline, 10 – hot water supply heat exchanger, 11 – cold water supply, 12– technological apparatus, 13 — hot water supply pipeline, 14 — hot water recirculation pipeline, 15 — boiler room, 16 — hot water boiler, 17 — pump.

With a significant distance from the heat source from the heat-supplied area (with "suburban" CHPPs), combined heat supply systems are advisable, which are a combination of a one-pipe system and a semi-closed two-pipe system (Figure 8.1, d). In such a system, the peak hot water boiler, which is part of the CHPP, is located directly in the heat-supplied area, forming an additional hot water boiler room. From the CHPP to the boiler house, only such an amount of high-temperature water is supplied through one pipe, which is necessary for hot water supply. Inside the heat-supplied area, an ordinary semi-closed two-pipe system is arranged.

In the boiler house, water from the CHP plant is added to the water heated in the boiler from the return pipeline of the two-pipe system, and the total flow of water with a lower temperature than the temperature of the water coming from the CHP is sent to the district heating network. In the future, part of this water is used in local hot water supply systems, and the rest is returned to the boiler room.

Three-pipe systems are used in industrial heat supply systems with a constant flow of water supplied for technological needs (Figure 8.1, e). Such systems have two supply pipes. According to one of them, water with a constant temperature goes to technological devices and to heat exchangers for hot water supply, according to the other, water with a variable temperature goes to the needs of heating and ventilation. Chilled water from all local systems is returned to the heat source through one common pipeline.

Four-pipe systems (Figure 8.1, e), due to the high consumption of metal, are used only in small systems in order to simplify subscriber inputs. In such systems, water for local hot water supply systems is prepared directly at the heat source (in boiler houses) and is supplied through a special pipe to consumers, where it directly enters the local hot water supply systems. In this case, subscribers do not have heating installations for hot water supply and recirculated water from hot water supply systems is returned to the heat source for heating. The other two pipes in such a system are intended for local heating and ventilation systems.

TWO-PIPE WATER HEATING SYSTEMS

Closed and open systems... Two-pipe water systems are closed and open. These systems differ in the technology of water preparation for local hot water supply systems (Fig. 8.2). In closed systems for hot water supply, tap water is used, which is heated in surface heat exchangers with water from the heating network (Fig. 8.2, a). In open systems, water for hot water supply is taken directly from the heating network. The withdrawal of water from the supply and return pipes of the heating network is carried out in such quantities that, after mixing, the water acquires the temperature required for hot water supply (Figure 8.2, b).

Fig 8.2 ... Schematic diagrams of water preparation for hot water supply at subscriber's in two-pipe water heat supply systems... a — with a closed system, b — an open system, 1 — supply and return pipelines of the heating network; 2 — hot water supply heat exchanger, 3 — cold water supply, 4 — local hot water supply system, 5 — temperature regulator, 6 — mixer, 7 — reverse valve

In closed heat supply systems, the coolant itself is not consumed anywhere, but only circulates between the heat source and local heat consumption systems. This means that such systems are closed in relation to the atmosphere, which is reflected in their name. For closed systems, theoretically, equality is valid, i.e. the amount of water leaving the source and coming to it is the same. In real systems, however, always. Part of the water is lost from the system through the leaks in it: through the glands of pumps, expansion joints, fittings, etc. These water leaks from the system are small and, with good operation, do not exceed 0.5% of the volume of water in the system. However, even in such quantities, they bring certain damage, since both heat and coolant are uselessly lost with them.

The practical inevitability of leaks makes it possible to exclude expansion vessels from the equipment of water heating systems, since water leaks from the system always exceed the possible increase in the volume of water with an increase in its temperature during the heating period. The system is replenished with water to compensate for leaks at the heat source.

In open systems, even in the absence of leaks, inequality is characteristic. The mains water, pouring out from the water taps of the local hot water supply systems, comes into contact with the atmosphere, i.e. such systems are open to the atmosphere. Replenishment of open systems with water usually occurs in the same way as for closed systems, at a heat source, although, in principle, in such systems, replenishment is possible at other points in the system. The amount of make-up water in open systems is much higher than in closed ones. If in closed systems the make-up water only covers the water leaks from the system, then in open systems it must also compensate for the foreseen water withdrawal.

The absence of open heat supply systems at subscriber inputs of surface heat exchangers for hot water supply and their replacement with cheap mixing devices is the main advantage of open systems over closed ones. The main disadvantage of open systems is the need to have a more powerful installation at the heat source than closed systems for the return of the make-up water in order to avoid the appearance of corrosion and scale in heating installations and heating networks.

Along with simpler and cheaper subscriber inputs, open systems have the following positive qualities in comparison with closed systems:

a) allow the use in large quantities of low-grade waste heat, which is also available at the CHP(heat of turbine condensers), and in a number of industries, which reduces fuel consumption for the preparation of a coolant;

b) provide an opportunity decrease in the estimated productivity of the heat source and by averaging the heat consumption for hot water supply when installing central hot water accumulators;

v) increase service life local hot water supply systems, as they receive water from heating networks, which does not contain aggressive gases and scale-forming salts;

G) reduce the diameters of cold water distribution networks (by about 16%), supplying water to subscribers for local hot water supply systems through heating pipelines;

e) let go to one-pipe systems with the coincidence of water consumption for heating and hot water supply .

The disadvantages of open systems in addition to the increased costs associated with the treatment of large amounts of make-up water, include:

a) the possibility, with insufficiently thorough treatment of water, the appearance of color in the disassembled water, and in the case of connecting radiator heating systems to heating networks through mixing nodes (elevator, pumping), also the possibility of contamination of the disassembled water and the appearance of odor in it due to sediment deposition in radiators and the development of special bacteria in them;

b) increasing complexity of control over the density of the system, since in open systems the amount of make-up water does not characterize the amount of water leakage from the system, as in closed systems.

The low hardness of the original tap water (1–1.5 mg eq / l) facilitates the use of open systems, eliminating the need for expensive and complex anti-scale water treatment. It is advisable to use open systems even with very hard or corrosive source waters, because with such waters in closed systems it is necessary to arrange water treatment at each subscriber input, which is many times more complicated and expensive than a single treatment of make-up water at a heat source in open systems.

SINGLE PIPE WATER HEATING SYSTEMS

A diagram of the subscriber input of a one-pipe heat supply system is shown in Figure 8.3.

Rice. 8.3. Scheme of input of a one-pipe heat supply system

Mains water in an amount equal to the average hourly flow rate of water in the hot water supply is supplied to the input through the constant flow machine 1. Machine 2 redistributes the mains water between the hot water supply mixer and the heating heat exchanger 3 and provides the set temperature of the water mixture from the heating supply after the heat exchanger. V at night, when there is no water withdrawal, the water entering the hot water supply system is drained into the storage tank 6 through the automatic back-up machine 5 (automatic "upstream"), which ensures that the local systems are filled with water. With a water intake greater than average, pump 7 additionally supplies water from the tank to the hot water supply system. The circulating water of the hot water supply system is also drained into the accumulator through the automatic booster 4. To compensate for heat losses in the circulation circuit, including the accumulator tank, the automatic device 2 maintains the water temperature slightly higher than that usually accepted for hot water supply systems.

STEAM HEATING SYSTEMS

Figure 8.4. Schematic diagrams of steam heat supply systems

a - one-pipe without condensate return; b – two-pipe with condensate return; in - three-pipe with condensate return; 1 – heat source; 2 – steam line; 3-subscriber input; 4 – ventilation heater; 5 - heat exchanger of the local heating system; 6 - heat exchanger of the local hot water supply system; 7 – technological apparatus; 8 – condensate drain; 9 – drainage; 10 – condensate collection tank; 11 – condensate pump; 12 – check valve; 13 – condensate line

Like water, steam heat supply systems are single-pipe, double-pipe and multi-pipe (Fig. 8.4)

In a one-pipe steam system (Fig. 8.4, a), steam condensate does not return from heat consumers to the source, but is used for hot water supply and technological needs or is discharged into the drain. Such systems low-cost and used at low steam consumption.

Two-pipe steam systems with condensate return to the heat source (Figure 8.4, b) are most common in practice... Condensate from individual local heat consumption systems is collected in a common tank located at the heating point, and then pumped to the heat source by a pump. Steam condensate is a valuable product: it does not contain hardness salts and dissolved aggressive gases and allows you to save up to 15% of the heat contained in the steam... Preparing new portions of feed water for steam boilers usually requires significant costs, in excess of the cost of returning the condensate. The question of the expediency of returning the condensate to the heat source is decided in each specific case on the basis of technical and economic calculations.

Multi-pipe steam systems (Fig. 8.4, c) are used at industrial sites when receiving steam from a CHP and in the case of if the production technology requires a pair of different pressures... The costs of building separate steam pipelines for steam of different pressures turn out to be less than the cost of overconsumption of fuel at a CHP when steam is supplied only for one, the highest pressure and its subsequent reduction for subscribers who need a pair of lower pressure... Condensate return in three-pipe systems is carried out through one common condensate line. In a number of cases, double steam pipelines are also laid at the same steam pressure in them in order to provide reliable and uninterrupted steam supply to consumers. The number of steam pipelines can be more than two, for example, when reserving the supply of steam of different pressures from the CHPP or if it is expedient to supply steam of three different pressures from the CHPP.

At large industrial hubs that unite several enterprises, are being built complex water and steam systems with the supply of steam for the technology and water for the needs of heating and ventilation.

At the subscriber inputs of systems, in addition to devices providing heat transfer to local heat consumption systems, The system for collecting condensate and returning it to the heat source is also of great importance.

The pairs arriving at the subscriber input usually fall into distributor comb, from where directly or through a pressure reducing valve (automatic pressure "after itself") is directed to the heat-using devices.

The correct choice of coolant parameters is of great importance. When supplying heat from boiler houses, it is rational, as a rule, to choose high parameters of the coolant that are permissible according to the conditions of the technology for transporting heat through the network and using it in subscriber installations. An increase in the parameters of the coolant leads to a decrease in the diameters of the heating network and a decrease in pumping costs (for water). When heating, it is necessary to take into account the influence of the parameters of the heat carrier on the economy of the CHPP.

The choice of a closed or open water heating system depends mainly on the conditions of the CHP plant water supply, the quality of tap water (hardness, corrosiveness, oxidizability) and the available sources of low-grade heat for hot water supply.

A prerequisite for both open and closed heat supply systems is ensuring stable quality of hot water at subscribers in accordance with GOST 2874-73 "Drinking water". In most cases the quality of the source tap water determines the choice of the heat supply system (STS).

Closed system: saturation index J> -0.5; carbonate hardness Zh to<7мг-экв/л; (Сl+SО 4) 200мг/л; перманганатная окисляемость не регламентируется.

In an open system: permanganate oxidizability of O<4мг/л, индекс насыщения, карбонатная жёсткость, концентрация хлорида и сульфатов не регламентируется.

With increased oxidizability (O> 4 mg / l), microbiological processes develop in stagnant zones of open heat supply systems (radiators, etc.), the consequence of which is sulfide pollution of water. So the water taken from heating installations for hot water supply has an unpleasant hydrogen sulphide smell.

In terms of energy performance and initial costs, modern two-pipe closed and open TS systems are on average equivalent. In terms of initial cost, open systems can have some economic benefits. if there are soft water sources at the CHPP that does not need water treatment and meets sanitary standards for drinking water. The subscribers' cold water supply network is unloaded and requires additional supplies to the CHP. In operation, open systems are more difficult than closed ones due to the instability of the hydraulic regime of the heating network, the complication of sanitary control of the density of the system.

During long-distance transportation with a high load of EBC, in the presence of water sources that meet sanitary standards near a CHPP or boiler house, it is economically justified to use an open TS system with one-pipe (unidirectional) transit and two-pipe distribution network.

In case of ultra-long-distance transportation of heat over a distance of about 100-150 km or more, it is more expedient to check the efficiency of using a chymothermal heat transfer system (in a chemically bound state, for example methane + water = CO + 3H 2).

9. Equipment for CHP. Basic equipment (turbines, boilers).

The equipment of heat treatment stations can be roughly divided into primary and secondary... TO the main equipment of the CHP and heating and industrial boiler houses include turbines and boilers. CHP plants are classified according to the type of predominant heat load for heating, industrial heating and industrial. Turbines of the T, PT, and R types are installed on them, respectively. XXII Congress of the CPSU (LMZ), Nevsky and Kirovsky plants in Leningrad, Kaluga turbine, Bryansk engineering and Kharkov turbo-generator plants. Currently, large cogeneration turbines are produced by the Ural Turbomotor Plant named after V.I. K. E. Voroshilova (UTMZ).

The first domestic turbine with a capacity of 12 MW was created in 1931. Since 1935, all CHPPs were built for steam parameters for turbines of 2.9 MPa and 400 ° C, and the import of heating turbines was practically stopped. Beginning in 1950, the Soviet power industry entered a period of intensive growth in the efficiency of power supply installations, and the process of enlarging their main equipment and capacities continued due to the increase in thermal loads. In 1953-1954. In connection with the growth of oil production in the Urals, the construction of a number of high-capacity oil refineries began, for which a combined heat and power plant with a capacity of 200-300 MW was required. Two-sampling turbines with a capacity of 50 MW were created for them (in 1956 at a pressure of 9.0 MPa at the Leningrad Metal Plant and in 1957 at UTMZ at a pressure of 13.0 MPa). In just 10 years, more than 500 turbines with a pressure of 9.0 MPa with a total capacity of about 9 * 10 3 MW were installed. The unit capacity of the CHPP of a number of electrical systems has increased to 125-150 MW. As the technological heat load of oil refineries increases, as well as With the beginning of the construction of chemical plants for the production of fertilizers, plastics and artificial fibers, which needed steam up to 600-800 t / h, it became necessary to resume the production of back pressure turbines. The production of such turbines for a pressure of 13.0 MPa with a capacity of 50 MW was started at LMZ in 1962. The development of housing construction in large cities has created a basis for the construction of a significant number of heating power plants with a capacity of 300-400 MW and more. For this purpose, the production of turbines T-50-130 with a capacity of 50 MW at UTMZ began in 1960, and in 1962 turbines T-100-130 with a capacity of 100 MW. The fundamental difference between these types of turbines is the use of two-stage heating of heating system water in them due to the lower steam extraction with a pressure of 0.05-0.2 MPa and the upper one 0.06-0.25 MPa. These turbines can be converted to back pressure ( deteriorated vacuum) with condensation of exhaust vapor in a special surface of the network bundle located in the condenser for heating water. In some CHP plants, the condensers of the reduced vacuum turbines are used entirely as main heaters. By 1970, the unit capacity of heating CHPPs had reached 650 MW (CHPP No.20 Mosenergo), and industrial heating plants - 400 MW (Tolyatti CHPP). The total supply of steam at such stations is about 60% of the total supplied heat, and at some CHPPs it exceeds 1000 t / h.

A new stage in the development of cogeneration turbine construction is the development and creation of even larger turbines that will further increase the efficiency of thermal power plants and reduce the cost of their construction. Turbine T-250, capable of providing heat and electricity to a city with a population of 350 thousand people, is designed for supercritical steam parameters of 24.0 MPa, 560 ° C with intermediate superheating of steam at a pressure of 4.0 / 3.6 MPa to a temperature of 565 ° C ... The PT-135 turbine for a pressure of 13.0 MPa has two heating outlets with independent pressure control within the range of 0.04-0.2 MPa in the lower outlet and 0.05-0.25 MPa in the upper one. This turbine also provides for industrial extraction with a pressure of 1.5 ± 0.3 MPa. The R-100 backpressure turbine is intended for use at thermal power plants with significant consumption of process steam. From each turbine, approximately 650 t / h of steam with a pressure of 1.2-1.5 MPa can be released with the possibility of increasing it at the exhaust to 2.1 MPa. To supply consumers, steam from the additional unregulated extraction of the turbine with a pressure of 3.0-3.5 MPa can also be used. The T-170 turbine for a steam pressure of 13.0 MPa and a temperature of 565 ° C without intermediate overheating, both in terms of electric power and the amount of extracted steam, occupies an intermediate place between the T-100 and T-250 turbines. It is advisable to install this turbine at medium-sized city CHPPs with significant utilities load. The unit capacity of the CHP plant continues to grow. At present, CHPPs with an electric capacity of more than 1.5 million kW are already being operated, built and designed. Large urban and industrial CHP plants will require the development and creation of even more powerful units. Work has already begun to determine the profile of cogeneration turbines with a unit capacity of 400-450 MW.

In parallel with the development of turbine construction, more powerful boiler units were created. In 1931-1945. Direct-flow boilers of domestic design, generating steam with a pressure of 3.5 MPa and a temperature of 430 ° C, are widely used in the power industry. Currently, boiler units with a capacity of 120, 160 and 220 t / h with chamber combustion of solid fuels, as well as fuel oil and gas are produced for installation at CHPPs with turbines with a capacity of up to 50 MW with steam parameters of 9 MPa and 500-535 ° C. The designs of these boilers have been developed since the 50s by almost all the main boiler plants in the country - Taganrog, Podolsk and Barnaul. Common to these boilers is the U-shaped layout, the use of natural circulation, a rectangular open combustion chamber and a steel tubular air heater.

In 1955-1965. Along with the development of units with parameters of 10 MPa and 540 ° C at TPPs, larger turbines and boiler units with parameters of 14 MPa and 570 ° C were created. Of these, the most widespread are turbines with a capacity of 50 and 100 MW with boilers from the Taganrog Boiler Plant (TKZ) with a capacity of 420 t / h of types TP-80 - TP-86 for solid fuel and TGM-84 for gas and fuel oil. The most powerful unit of this plant, used at CHPPs of subcritical parameters, is a unit of the TGM-96 type with a combustion chamber for burning gas and fuel oil with a capacity of 480-500 t / h.

A block-type boiler-turbine (T-250) design for supercritical steam parameters with reheating required the creation of a once-through boiler with a steam capacity of about 1000 t / h. To reduce the cost of building a CHP, Soviet scientists M.A. The expediency of heating network water at the CHPP in the peak part of the schedule with special peak hot water boilers was proved, refusing to use more expensive steam power boilers for these purposes. Research VTI them. F.E.Dzerzhinsky completed the development and production of a number of standard sizes of unified tower gas-and-oil water-heating boiler units with unit heating capacities of 58, 116 and 210 MW. Later, boilers of lower capacities were developed. Unlike tower-type boilers (PTVM), KVGM boilers are designed to operate with artificial draft. Such boilers with a heating capacity of 58 and 116 MW have a U-shaped layout and are designed to operate in the main mode.

The profitability of steam turbine CHPPs for the European part of the USSR at one time was achieved with a minimum heat load of 350-580 MW. Therefore, along with the construction of CHPPs, the construction of industrial and heating boiler plants equipped with modern hot water and steam boilers is being carried out on a large scale. District thermal stations with boilers of the PTVM, KVGM type are used at loads of 35-350 MW, and steam boilers with boilers of the DKVR type and others are used at loads of 3.5-47 MW. Small villages and agricultural facilities, residential areas of individual cities are heated by small boiler houses with cast iron and steel boilers with a capacity of up to 1.1 MW.

10. Equipment for CHP. Auxiliary equipment (heaters, pumps, compressors, steam converters, evaporators, ROU reduction and cooling units, condensate tanks).

11. Water treatment. Water quality standards.

12. Water treatment. Clarification, softening (precipitation, cation exchange, stabilization of water hardness).

13. Water treatment. Deaeration.

14. Thermal consumption. Seasonal load.

15. Thermal consumption. Year-round load.

16. Thermal consumption. Rossander chart.

Introduction

General information and concept of boiler plants

1 Classification of boiler plants

Types of heating boilers for heating buildings

1 Gas boilers

2 Electric boilers

3 Solid fuel boilers

Types of boilers for heating buildings

1 Gas-tube boilers

2 Water tube boilers

Conclusion

Bibliography

Introduction

Living in temperate latitudes, where most of the year is cold, it is necessary to provide heat supply to buildings: residential buildings, offices and other premises. Heat supply provides comfortable living, if it is an apartment or house, productive work, if it is an office or warehouse.

First, let's figure out what is meant by the term "Heat supply". Heat supply is the supply of heating systems of a building with hot water or steam. Thermal power plants and boiler houses are the usual source of heat supply. There are two types of heat supply for buildings: centralized and local. With a centralized one, individual districts (industrial or residential) are supplied. For the efficient operation of a centralized heat supply network, it is built, dividing it into levels, the work of each element is to perform one task. With each level, the task of the element decreases. Local heat supply - the supply of heat to one or more houses. Centralized heating networks have a number of advantages: lower fuel consumption and cost savings, use of low-grade fuel, and improved sanitary conditions in residential areas. The district heating system includes a heat source (CHP), a heating network and heat-consuming installations. The combined heat and power plant produces heat and energy. Sources of local heat supply are stoves, boilers, water heaters.

My goal is to get acquainted with the general information and concept about boiler installations, which boilers are used to supply heat to buildings.

1. General information and concepts about boiler plants

A boiler plant is a complex of devices located in special rooms and serving to convert the chemical energy of the fuel into thermal energy of steam or hot water. The main elements of the boiler plant are a boiler, a combustion device (furnace), feed and draft devices.

A boiler is a heat exchange device in which heat from hot products of fuel combustion is transferred to water. As a result, in steam boilers, water turns into steam, and in hot water boilers it is heated to the required temperature.

The combustion device is used to burn fuel and convert its chemical energy into heat of heated gases.

Feeding devices (pumps, injectors) are designed to supply water to the boiler.

The draft device consists of blowing fans, a system of gas ducts, smoke exhausters and a chimney, with the help of which the required amount of air is supplied to the furnace and the movement of combustion products through the boiler gas ducts, as well as their removal into the atmosphere. Combustion products, moving along the gas ducts and in contact with the heating surface, transfer heat to the water.

To ensure more economical operation, modern boiler plants have auxiliary elements: a water economizer and an air heater, which respectively serve to heat water and air; devices for fuel supply and ash removal, for cleaning flue gases and feed water; thermal control devices and automation equipment that ensure the normal and uninterrupted operation of all parts of the boiler room.

Depending on the purpose for which thermal energy is used, boiler houses are divided into energy, heating and production and heating.

Power boiler houses supply steam to steam power plants that generate electricity and are usually part of a power plant complex. Heating and industrial boilers are built at industrial enterprises and provide heat energy to heating and ventilation systems, hot water supply of buildings and production processes. Heating boilers are intended for the same purposes, but serve residential and public buildings. They are divided into free-standing, interlocked, i.e. adjacent to other buildings, and embedded in buildings. Recently, more and more freestanding enlarged boiler houses are being built with the expectation of servicing a group of buildings, a residential quarter, a microdistrict. The device of boiler houses built into residential and public buildings is currently allowed only with appropriate justification and agreement with the sanitary supervision authorities. Low-power boiler houses (individual and small group) usually consist of boilers, circulation and feed pumps and draft devices. Depending on this equipment, the dimensions of the boiler room are mainly determined. Boiler houses of medium and high power - 3.5 MW and above - are distinguished by the complexity of the equipment and the composition of service and utility rooms. The space-planning solutions of these boiler houses must meet the requirements of the Sanitary Standards for the Design of Industrial Enterprises.

1.1 Classification of boiler plants

Boiler plants, depending on the nature of the consumers, are divided into energy, production-heating and heating. By the type of heat carrier produced, they are divided into steam (for generating steam) and hot water (for generating hot water).

Power boiler plants generate steam for steam turbines in thermal power plants. Such boiler houses are usually equipped with boilers of large and medium power, which generate steam with increased parameters.

Industrial heating boiler plants (usually steam) generate steam not only for industrial needs, but also for heating, ventilation and hot water supply.

Heating boiler installations (mainly hot water, but they can also be steam) are designed to service heating systems of industrial and residential premises.

Depending on the scale of heat supply, heating boiler houses are divided into local (individual), group and district.

Local boiler houses are usually equipped with hot water boilers with water heating to a temperature of no more than 115 ° C or steam boilers with an operating pressure of up to 70 kPa. Such boiler rooms are designed to supply heat to one or more buildings.

Group boiler plants provide heat to groups of buildings, residential areas or small neighborhoods. Such boiler houses are equipped with both steam and hot water boilers, as a rule, with a higher heating capacity than boilers for local boiler houses. These boiler rooms are usually located in specially constructed separate buildings.

District heating boilers are used to supply heat to large residential areas: they are equipped with relatively powerful hot water or steam boilers.

2. Types of heating boilers

.1 Gas boilers

If the main gas is supplied to the site, then, in the overwhelming majority of cases, heating the house using a gas boiler is optimal, since you cannot find cheaper fuel. There are many manufacturers and models of gas boilers. In order to make it easier to understand this variety, we will divide all gas boilers into two groups: floor-standing and wall-mounted boilers. Wall-mounted and floor-standing boilers have different designs and configurations.

A floor-standing boiler is a traditional, conservative thing and has not undergone major changes over many decades. The heat exchanger for floor-standing boilers is usually made of cast iron or steel. There are different opinions about which material is better. On the one hand, cast iron is less susceptible to corrosion, a cast iron heat exchanger is usually made thicker, which can have a positive effect on its service life. At the same time, the cast iron heat exchanger also has disadvantages. It is more fragile, and, therefore, there is a risk of microcracking during transportation and loading and unloading. In addition, during the operation of cast iron boilers when using hard water, due to the design features of cast iron heat exchangers, and the properties of cast iron itself, their destruction occurs over time as a result of local overheating. If we talk about steel boilers, then they are lighter, they are not very afraid of shocks during transportation. At the same time, if used improperly, the steel heat exchanger can corrode. But, it is not very difficult to create normal operating conditions for a steel boiler. It is important that the temperature in the boiler does not drop below the dew point temperature. A good designer will always be able to create a system that will maximize the life of the boiler. In turn, all floor-standing gas boilers can be divided into two main groups: with atmospheric and pressurized (sometimes they are called replaceable, ventilated, mounted) burners. The former are simpler, cheaper and quieter. Boilers with forced draft burners have higher efficiency and are significantly more expensive (taking into account the cost of the burner). Boilers for operation with forced draft burners have the option of installing burners operating either on gas or on liquid fuel. The power of floor-standing gas boilers with an atmospheric burner, in most cases, ranges from 10 to 80 kW (but there are companies that produce more powerful boilers of this type), while models with replaceable inflatable

burners can reach a power of several thousand kW. In our conditions, another parameter of a gas boiler is very important - the dependence of its automation on electricity. Indeed, in our country, there are frequent cases of problems with electricity - somewhere it is supplied intermittently, and in some places it is completely absent. Most modern gas boilers with atmospheric burners operate independently of the presence of a power supply. As for imported boilers, it is clear that there are no such problems in Western countries, and the question often arises, are there good imported gas boilers operating independently of electricity? Yes there are. This autonomy can be achieved in two ways. The first is to simplify the boiler control system as much as possible and, due to the almost complete absence of automation, achieve independence from electricity (this also applies to domestic boilers). In this case, the boiler can only maintain the set temperature of the coolant, and will not be guided by the air temperature in your room. The second, more progressive method, is using a heat generator, which generates electricity from heat, which is necessary for the operation of the boiler automation. These boilers can be used with remote room thermostats that will control the boiler and maintain the room temperature you set.

Gas boilers can be single-stage (operate only at one power level) and two-stage (2 power levels), as well as with modulation (smooth regulation) of power, since the full power of the boiler requires about 15-20% of the heating season, and 80-85% Since it is unnecessary, it is clear that it is more economical to use a boiler with two power levels or power modulation. The main advantages of a two-stage boiler are: an increase in the life of the boiler, due to a decrease in the frequency of switching on / off the burner, operation at the 1st stage with a reduced power and a decrease in the number of switching on / off of the burner saves gas and, consequently, money.

Wall-mounted boilers appeared relatively recently, but even during this relatively short time period, they won a mass of supporters around the world. One of the most accurate and capacious definitions of these devices is "mini boiler room". This term did not appear by chance, because in a small case there is not only a burner, a heat exchanger and a control device, but also, in most models, one or two circulation pumps, an expansion tank, a system that ensures the safe operation of the boiler, a pressure gauge, a thermometer, and many others. elements, without which the work of a normal boiler room cannot do. Despite the fact that the most advanced technical developments in the field of heating have come to life in wall-mounted boilers, the cost of "wall-mountings" is often 1.5-2 times lower than that of their floor-standing counterparts. Another significant advantage is the ease of installation. Often, buyers believe that ease of installation is a virtue that should only be of concern to installers. This is not entirely true, because the amount that a real consumer will have to pay for installing a wall-mounted boiler or for installing a boiler room, where a boiler, boiler, pumps, expansion tank and much more are installed separately, differs very significantly. Compactness and the ability to fit a wall-mounted boiler into almost any interior is another plus of this class of boilers.

Despite the fact that the most advanced technical developments in the field of heating have come to life in wall-mounted boilers, the cost of "wall-mountings" is often 1.5-2 times lower than that of their floor-standing counterparts. Another significant advantage is the ease of installation. Often, buyers believe that ease of installation is a virtue that should only be of concern to installers. This is not entirely true, because the amount that a real consumer will have to pay for installing a wall-mounted boiler or for installing a boiler room, where a boiler, boiler, pumps, expansion tank and much more are installed separately, differs very significantly. Compactness and the ability to fit a wall-mounted boiler into almost any interior is another plus of this class of boilers.

According to the method of exhaust gas removal, all gas boilers can be divided into models with natural draft (exhaust gases are removed due to the draft generated in the chimney) and with forced draft (using a fan built into the boiler). Most firms that produce wall-mounted gas boilers produce models, both with natural draft and forced. Natural draft boilers are well known to many and the chimney above the roof does not surprise anyone. Boilers with forced draft appeared quite recently and have a lot of advantages during installation and operation. As already mentioned above, the exhaust gases from these boilers are removed using a fan built into them. Such models are ideal for rooms without a traditional chimney, since the combustion products in this case are removed through a special coaxial chimney, for which it is enough to make only a hole in the wall. A coaxial chimney is also often called a "pipe within a pipe". Through the inner pipe of such a chimney, the combustion products are removed to the street with the help of a fan, and air enters through the outer pipe. In addition, these boilers do not burn oxygen from the premises, do not require additional inflow of cold air into the building from the street to maintain the combustion process, and allow to reduce investment costs during installation, because no need to make an expensive traditional chimney, instead of which a short and inexpensive coaxial one is successfully used. Forced draft boilers are also used when there is a traditional chimney, but the intake of combustion air from the room is undesirable.

By the type of ignition, wall-mounted gas boilers can be with electric or piezo ignition. Electric ignition boilers are more economical, since there is no igniter with a constantly burning flame. Due to the absence of a constantly burning wick, the use of boilers with electric ignition can significantly reduce gas consumption, which is most important when using liquefied gas. The savings in liquefied gas can reach 100 kg per year. There is one more plus of boilers with electric ignition - if the power supply is temporarily cut off, the boiler will automatically turn on when the power supply resumes, and the model with piezo ignition will have to be turned on manually.

According to the type of burner, wall-mounted boilers can be divided into two types: with a conventional burner and with a modulating burner. The modulating burner provides the most economical operating mode, since the boiler automatically adjusts its output depending on the heat demand. In addition, the modulating burner also provides maximum comfort in DHW mode, allowing you to maintain the hot water temperature at a constant set level.

Most wall-hung boilers are equipped with devices that ensure their safe operation. So the flame detector in the event of a loss of flame turns off the gas supply, the blocking thermostat in the event of an emergency increase in the boiler water temperature turns off the boiler, a special device turns off the boiler in case of power failure, another device blocks the boiler when the gas is turned off. There is also a boiler shutdown device when the volume of the coolant drops below the norm and a draft control sensor.

2.2 Electric boilers

There are several main reasons for limiting the distribution of electric boilers: far from all areas it is possible to allocate the electrical power required for heating a house (for example, a house with an area of ​​200 square meters requires about 20 kW), a very high cost of electricity, power outages. There are indeed many advantages of electric boilers. Among them: relatively low price, ease of installation, lightweight and compact, they can be hung on the wall, as a result - space saving, safety (no open flame), ease of operation, an electric boiler does not require a separate room (boiler room), an electric boiler does not require installation of the chimney, the electric boiler does not need special care, noiseless, the electric boiler is environmentally friendly, there are no harmful emissions and odors. In addition, in cases where power outages are possible, an electric boiler is often used in tandem with a reserve solid fuel one. The same option is used to save electricity (first, the house is heated with cheap solid fuel, and then the temperature is automatically maintained using an electric boiler).

It is worth noting that when installed in large cities with strict environmental standards and coordination problems, electric boilers also often outperform all other types of boilers (including gas boilers). Briefly about the design and equipment of electric boilers. An electric boiler is a fairly simple device. Its main elements are a heat exchanger, consisting of a tank with electric heaters (heating elements) fixed in it, and a control and regulation unit. Electric boilers of some companies are supplied already equipped with a circulation pump, programmer, expansion tank, safety valve and filter. It is important to note that low-power electric boilers are available in two different versions - single-phase (220 V) and three-phase (380 V).

Boilers over 12 kW are usually produced with three-phase only. The overwhelming majority of electric boilers with a capacity of more than 6 kW are produced in multistage, which allows efficient use of electricity and does not turn on the boiler at full capacity during transition periods - in spring and autumn. When using electric boilers, the most important is the rational use of the energy carrier.

2.3 Solid fuel boilers

Fuel for solid fuel boilers can be wood (wood), brown or coal, coke and peat briquettes. There are both "omnivorous" models that can operate on all of the above types of fuel, and those that work on some of them, but with greater efficiency. One of the main advantages of most solid fuel boilers is that they can be used to create a completely autonomous heating system. Therefore, more often such boilers are used in areas where there are problems with the supply of main gas and electricity. There are two more arguments in favor of solid fuel boilers - availability and low cost of fuel. The disadvantage of most representatives of boilers of this class is also obvious - they cannot operate in a fully automatic mode and require regular fuel loading.

It is worth noting that there are solid fuel boilers that combine the main advantage of models that have existed for many years - independence from electricity and are capable of automatically maintaining the set temperature of the coolant (water or antifreeze). Automatic temperature maintenance is carried out as follows. The boiler has a sensor that monitors the temperature of the coolant. This sensor is mechanically connected to the damper. If the temperature of the coolant becomes higher than the one set by you, then the damper is automatically closed and the combustion process slows down. When the temperature drops, the damper opens slightly. Thus, this device does not require an electrical connection. As mentioned above, most traditional solid fuel boilers are capable of operating on lignite and hard coal, wood, coke, briquettes.

Overheating protection is ensured by the presence of a cooling water circuit. This system can be controlled manually, i.e. when the temperature of the coolant rises, it is necessary to open the valve on the coolant outlet (the valve on the inlet is constantly open). Moreover, this system can also be controlled automatically. To do this, a temperature lowering valve is installed on the outlet pipe, which will automatically open when the coolant reaches its maximum temperature. In addition, what fuel to use for heating your home, it is very important to choose the right boiler power required. Power is usually expressed in kW. Approximately 1 kW of power is required for heating 10 sq. m of a well-insulated room with a ceiling height of up to 3 m. It must be borne in mind that this formula is very approximate.

The final power calculation should be trusted only by professionals who, in addition to the area (volume), will take into account many more factors, including the material and thickness of the walls, the type, size, number and location of windows, etc.

Boilers with pyrolysis wood combustion have a higher efficiency (up to 85%) and allow automatic power control.

The disadvantages of pyrolysis boilers, first of all, can be attributed to a higher price compared to traditional solid fuel boilers. By the way, there are boilers that work not only on wood, but also on straw boilers. When choosing and installing a solid fuel boiler, it is very important to comply with all the requirements for the chimney (its height and internal section).

3. Types of boilers for heating buildings

gas boiler heat supply

There are two main types of steam boilers: gas-tube and water-tube. All boilers (fire-tube, smoke-tube and fire-tube boilers), in which high-temperature gases pass inside the flame and smoke tubes, giving off heat to the water surrounding the tubes, are called gas-tube boilers. In water-tube boilers, heated water flows through the pipes, and the flue gases wash the pipes from the outside. Gas-tube boilers are supported on the side walls of the furnace, while water-tube boilers are usually attached to the frame of the boiler or building.

3.1 Gas-tube boilers

In modern heat power engineering, the use of gas-tube boilers is limited by a thermal power of about 360 kW and an operating pressure of about 1 MPa.

The fact is that when designing a high-pressure vessel, such as a boiler, the wall thickness is determined by the specified values ​​of the diameter, working pressure and temperature.

When the specified limiting parameters are exceeded, the required wall thickness turns out to be unacceptably large. In addition, safety requirements must be taken into account, since an explosion of a large steam boiler, accompanied by an instantaneous release of large volumes of steam, can lead to a disaster.

With the current state of the art and existing safety requirements, gas-tube boilers can be considered obsolete, although many thousands of such boilers with a thermal power of up to 700 kW are still in operation, serving industrial enterprises and residential buildings.

3.2 Water tube boilers

The water tube boiler was developed in response to the ever increasing demands for increased steam production and steam pressure. The fact is that when steam and water of increased pressure are in a pipe of not very large diameter, the requirements for the wall thickness are moderate and easy to fulfill. Water-tube steam boilers are much more complex in design than gas-tube boilers. However, they warm up quickly, are practically explosion-proof, can be easily adjusted according to load changes, are easy to transport, easily reconfigured in design solutions, and allow significant overload. The disadvantage of a water-tube boiler is that there are many units and assemblies in its design, the connections of which should not allow leaks at high pressures and temperatures. In addition, the pressure units of such a boiler are difficult to access for repairs.

A water-tube boiler consists of bundles of pipes connected at their ends to a drum (or drums) of moderate diameter, the entire system being mounted above the combustion chamber and enclosed in an outer casing. The baffles force the flue gases to pass through the tube bundles several times, resulting in a more complete heat transfer. Drums (of various designs) serve as reservoirs for water and steam; their diameter is chosen to be minimal in order to avoid the difficulties typical for gas-tube boilers. Water tube boilers are of the following types: horizontal with a longitudinal or transverse drum, vertical with one or more steam drums, radiation, vertical with a vertical or transverse drum and combinations of the above options, in some cases with forced circulation.

Conclusion

So, in conclusion, we can say that boilers are an important element in the heat supply of a building. When choosing stakes, it is necessary to take into account technical, technical and economic, mechanical and other indicators for a better type of heat supply to the building. Boiler plants, depending on the nature of the consumers, are divided into energy, production-heating and heating. By the type of heat carrier produced, they are divided into steam and hot water.

In my work, gas, electric, solid fuel types of boilers are considered, as well as types of stakes, such as gas-tube and water-tube boilers.

From the above, it is worth highlighting the pros and cons of various types of boilers.

The advantages of gas boilers are as follows: efficiency, compared to other types of fuel, ease of operation (boiler operation is fully automated), high power (you can heat a large area), the ability to install equipment in the kitchen (if the boiler power is up to 30 kW), compact size, environmental friendliness ( few harmful substances will be released into the atmosphere).

Disadvantages of gas boilers: before installation, it is necessary to obtain a permit from Gazgortekhnadzor, the danger of gas leakage, certain requirements for the room where the boiler is installed, the presence of automation that blocks the access of gas in the event of a leak or lack of ventilation.

Advantages of electric boilers: low price, ease of installation, compactness and low weight - electric boilers can be hung on the wall and save useful space, safety (no open flame), ease of operation, electric boilers do not require a separate room (boiler room), do not require installation of a chimney, do not require special care, noiseless, environmentally friendly - no harmful emissions and odors.

The main reasons limiting the distribution of electric boilers are far from all areas, it is possible to allocate several tens of kilowatts of electricity, a fairly high cost of electricity, power outages.

First, let's highlight the disadvantages of solid fuel boilers: first of all, solid fuel heating boilers use solid fuel, which has a relatively low heat transfer. Indeed, in order to heat a large house with high quality, you will have to spend a lot of fuel and time. In addition, the fuel will burn quite quickly - in two to four hours. After that, if the house is not heated enough, you will have to rekindle the fire. Moreover, for this, you will first need to clean the furnace from the formed coals and ash. Only then will it be possible to add fuel and re-kindle the fire. All this is done by hand.

On the other hand, solid fuel boilers have some advantages. For example, not picky about fuel. Indeed, they can work effectively on all types of solid fuels - wood, peat, coal, and in general, anything that can burn. Of course, it is possible to obtain such fuel in most regions of our country quickly and not too expensively, which is a serious argument in favor of solid fuel boilers. In addition, these boilers are completely safe, so they can be installed either in the basement of the house, or just nearby. At the same time, you can be sure that a terrible explosion will not occur due to fuel leakage. Of course, there is no need to equip a special place for storing fuel - to bury tanks for storing gas or diesel fuel in the ground.

Currently, there are two main types of steam boilers, namely gas-tube and water-tube. Gas-tube boilers are those boilers in which high-temperature gases flow inside the flame and smoke tubes, thereby giving off heat to the water that surrounds the tubes. Water-tube boilers are distinguished by the fact that heated water flows through the pipes, and the pipes are washed outside by gases.

Bibliography

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