Do-it-yourself solid fuel heating boilers for long burning. Do-it-yourself solid fuel boiler for long burning. Installation of a homemade boiler and an accelerating furnace

No! But this does not mean that I live in a world of limited space.
I don't have a car equipped gas equipment, but this does not mean that I do not understand this issue and do not have personal experience maintenance and operation. But I have two welding machines, a fashionable mask (certified in Europe), but I DID NOT LEARN how to cook.
And I don't want to study. That's not mine and that's it.
If there is no clear understanding Do it, buy a universal one. What's the question? Someone forbids? I will put myself a second one if it becomes necessary to heat with firewood, which is unlikely. Obviously, I will not chop firewood in a three-section Viadrus on an ongoing basis. And if the gas fails, I will buy a gas boiler, obviously I will not shove the burner into Viadrus. I do not need to think through the universality of not all occasions. I used to change cars every year, but I never found a universal one for myself. It will be necessary, I will collect boilers.
I didn’t delve into it, I don’t know ... it will be fine. I don't care.
I do not need...
Watch the video on the link, for 6 min 39 s a man of normal height, normally cleans a vertical heat exchanger ... That's the joke, that vertically in width put at least 10 sections of heat exchangers, the height does not change from this. This way you can make it the way you like it. At the same time, only the width or length can be changed, as it will be more convenient. And with a significant boiler power, of course, there will be a need for inflating.
Practice shows that when optimal mode the temperature of the rotten gases rises and the efficiency increases, and during smoldering the temperature of the rotten gases drops, but the efficiency sometimes drops by more than two times. I tested this in practice. I can burn a full furnace with a strangled draft and not heat the room
Because in the design of the boiler that you are talking about, the entire furnace flares up and there is no way to control the intensity of combustion.
In the design of the boiler that I suggested to the person, as an option, annealing goes at the bottom. And controlled by the amount of air supplied. Above the annealing zone, not intensive pyrolysis occurs, and the upper part of the bookmark is dried ... When the closed space is filled with pyrolysis gases, they have only one way, only through the annealing zone, through the nozzle ... I already wrote about this.
And if you look more broadly, then your practice is not a regularity for all types of fuel ... That's why I called the proposed design a clearly wood-burning boiler ... And the main plus is the controllability of the burning intensity.
The pursuit of a wildly low temperature of rotten gases on wood (I did not check it on anthracite) is an erroneous direction and a consequence of narrow thinking due to washing it ...
In the design I proposed, by controlling the intensity of combustion. You can easily keep Tuh gases 130-150*C. Is that a wildly low wood-burning rot? But again, this is a calculation for mass production. For yourself, you can still increase the area of \u200b\u200bthe heat exchanger and Tukh will be even lower. But here the question arises of the quality of firewood and chimney. And do not confuse Tukh with direct heat transfer and when you heat TA ...
On anthracite, there are also such miracles when the system works around the clock, with direct heat transfer WITHOUT TA. The boiler is 100% loaded at this moment, overboard + 8 * C, in the house 22-23 * C.
As you can see, combustion is easily controlled, the entire furnace does not ignite and everything is in order with efficiency. TA - three hundred years old goat button accordion.

We will send the material to you by e-mail

Before proceeding with the independent manufacture of solid fuel boilers, it is necessary to prepare sketches. They should include the main and additional elements. It is proposed to take the drawings of solid fuel boilers as a basis long burning. It is quite possible to make them with your own hands.

Appearance homemade design

Analogues with support for long burning differ from conventional boilers by the presence of two working chambers at once. In the first of them, the directly deposited fuel is burned, and in the second, the released gases are burned. Important role timely supply of oxygen. As a device for blowing air, a conventional fan with simple automation can be used.

Among the advantages of the units it should be noted:

the minimum number of bookmarks of fuel;
high work efficiency;
usage various kinds solid fuel;
a small amount of soot in the pipes during operation;
design reliability.

Note! Of the disadvantages, it is necessary to mention the complexity self-manufacturing. Although when using ready-made drawings of solid fuel boilers for long burning with your own hands, it is still possible to make a unit.

The process of manufacturing solid fuel boilers for long burning with your own hands: drawings and assembly

It should immediately be noted that structures can have both an upper gas combustion chamber and a lower one. In the first case, the combustion products enter the working compartment under the influence of natural forces, and in the second - with the help of accessory for air injection.

Since boilers with a lower afterburner are difficult to manufacture and require the installation of additional equipment during installation, it does not make much sense to consider them. It is faster and more economical to make a design with an upper chamber for burning gases.

Applicable Items

For the manufacture of the structure you will need:

pipe with a section of 500 mm and a length of 1300 mm;
pipe with a diameter of 450 mm and a length of 1500 mm;
pipe with a section of 60 mm and a length of 1200 mm;
two rings 25 mm wide and 500 mm in diameter;
metal corners and pieces of channel;
Metal sheet;
asbestos cloth;
hinges and handles.

Chassis assembly order

First of all, pipes with a cross section of 1500 and 1300 mm are inserted into each other. They are connected using a ring made from a corner measuring 25x25 mm. From sheet metal a circle with a diameter of 450 mm is cut out and fixed to the end of the pipe. It acts as the bottom. The result should be a small barrel.

A hole in the shape of a rectangle 15x10 cm is cut out from the bottom side of the structure for the ash pan door. The sash is attached to the opening with the help of a loop, and a valve is also installed.

A rectangular hole for the fuel chamber is made a little higher. Dimensions can be determined by yourself. The convenience of loading firewood or other fuel will depend on the correctly selected dimensions. Using the same technology, a door with a latch is installed.

At the top of the homemade structure, an exhaust pipe is made, through which the exhaust gases will flow into the chimney. On the sides, by welding, the pipes necessary for connecting to the heating system of the building are fixed. They must be threaded.

Air distributor device

A circle is cut out of a piece of tin with a cross section 20-30 mm smaller than the diameter of the inner part of the boiler. In the central part is done round hole for the air distribution pipe. Its diameter should be 6 cm. A pipe is inserted directly into the hole and welded to the base.

Pieces of a corner are attached to the bottom of the metal pancake. On the other hand, a loop is fixed by welding, which is necessary to move the structure up and down. To adjust the air supply directly to the combustion chamber, a damper is arranged.

A circle with a diameter of 500 mm, cut from a suitable piece of metal, is inserted into the structure. The upper end of the pipe is inserted into the hole, after which top cover the boiler is welded tightly. A cable is fixed to the loop, allowing the distributor to be lowered and raised.

Note! The simplest of all the schemes of long-burning solid fuel boilers was presented. Assemble with your own hands robust design it is not so difficult, especially if you have experience with welding and other tools.

Do-it-yourself solid fuel boiler for long burning: video for review

Another option is to use a gas cylinder for the hull. From it you can create a completely effective design for heating buildings. small sizes. To get acquainted with the features homemade device for heating it is suggested to look at the video. Do-it-yourself long-burning boiler without drawings can be made according to it.

Are there any negative reviews about the solid fuel boiler for long burning?

Sometimes consumers leave negative reviews about designs, but they are more likely to be associated with the general disadvantages that are inherent in solid fuel devices in general.

The following shortcomings can be distinguished:

for fuel storage it is necessary to use special premises or structures;
in any case, fuel must be loaded manually, despite the reduced number of loads;
when installing any models of solid fuel boilers, you need to take special measures security;
It is impossible to regulate the process of fuel combustion in the combustion chamber with particular accuracy.

Note! There are a lot of cons, but still solid fuel boilers are the only way out of the situation when the main lines of gas and electricity are not available.

On the cost of finished models for heating with solid fuel

If it is not possible to make a long-burning boiler or simply there is no desire, then you can purchase a finished design. It must be recognized that models for heating large rooms will be expensive. In the table you can see the prices for Stropuva boilers.

Article

For water heating of a private house, many designs of heating devices have been developed. Mine boilers stand out for their efficiency and unpretentiousness in maintenance. Their cost is quite high, so many craftsmen repeat factory models at home or make them according to their own design.

Mining boiler - design and principle of operation

Mine differs from others in the duration of burning and the features of the device. Often it is not necessary to throw up fuel, it has a large volume fuel chamber, and the combustion is slow. Two types of mine boilers have been developed: with conventional combustion and pyrolysis. Each has a similar arrangement of two chambers: fuel is burned in one, and a heat exchanger is arranged in the second.

A mine boiler with conventional combustion is simpler in design. Half of the entire volume is occupied by a firebox almost the entire unit high, but of small width and depth. On the side or top is a hatch for loading fuel. The furnace compartment, when viewed from above, resembles a mine, hence the name. Under the combustion chamber there is an ash pan, separated from it by a grate. Through the ash door, access is provided not only to it, but also to the firebox. The damper, located under the door, regulates the flow of air.

The second important part is a chamber with a heat exchanger filled with water or, if the boiler is not used for, a fire tube. Gases enter it from the firebox through the hole and exit through the chimney, simultaneously heating the heat exchanger. From it, water enters the system through pipes or hot air warms the room.

The mine-type pyrolysis boiler has a similar design, but is manufactured with some additional elements:

1. Chambers in which carbon monoxide burns and burns out. They are located below the heat exchange space, the walls are lined with fireclay bricks.
2. Several pipes with many small holes. Through them, air is supplied to the combustion and afterburning chambers.
3. At the top of the wall there are valves to separate the two chambers.

The principle of operation of the pyrolysis boiler is somewhat different. When burning, the air supply is limited, slow combustion causes the formation a large number gases that enter additional chambers and burn. The boilers burn any solid fuel: coal, firewood, pellets. One bookmark of coal is enough for five days, firewood - no more than thirty hours. Due to complete combustion, such boilers have a high efficiency - up to 90%.

Long burning device - classic scheme

The proposed design has a power of 22 kW, an efficiency of 75%. Works on wood for 10 hours without reloading, on coal - for a day. The firebox has a volume of 83 liters to the lower edge of the feed opening. The boiler is equipped with Polish-made automation: a control unit with a KG Elektronik SP-05 temperature sensor and a DP-02 fan. General view is shown in the drawing.

The device works as follows:

1. Firewood is loaded into the firebox and set on fire. The doors are hermetically sealed.
2. The required heating temperature is set on the control unit, at least 50°. The unit button is pressed and the fan starts to blow air.
3. When the set temperature is reached, the fan stops blowing air. Firewood smolders slowly, giving very little heat.
4. After a while, the temperature drops. The fan turns on again and the burning continues.

The electronic unit regulates the combustion process, which occurs when maximum efficiency. There is practically no smoldering, intensive burning and standby modes are used.

The following figure shows the inside view.

Solid fuel is burned classical pattern: heat is directly transferred to the walls of the water jacket and the roof of the tank. It has a built-in heat exchanger that takes heat from gases. Heated air is supplied to the furnace through an air duct from below. Fuel loaded in large quantities ensures a long operating time of the boiler. In anticipation, when the fan is turned off, the air is completely blocked by the gravitational damper, triggered by automation, the natural draft is blocked.

The drawing shows the back with a fire tube heat exchanger.

Manufacture of a heater - assembly sequence

When assembling with our own hands, we use the drawings, adhere to the indicated dimensions. The sequence is as follows:

1. We cut out the case from 4 mm metal: the bottom, side walls, cover, doorways. Everything is attached to the bottom, which is released to the sides, as in the drawing. Inside, we fix the corners by welding, which will serve as a shelf for the grate.
2. We carefully weld the joints and proceed to a 3 mm metal water jacket. It recedes from the walls of the case by 20 mm and, in order to install it, we weld steel strips onto the case. We weld the lining to them.
3. Installation of flame pipes on top of the boiler. We cut holes in the back and front walls, insert several pipes, weld at the ends.
4. We cut out the doors, weld two strips from the inside, put asbestos between them for sealing. Grids with a size of 360 × 460 mm are cut from the corners and welded to the shelves with an outer corner.
5. We cut fittings into the walls of the tank for the supply and return pipelines, the pipe of the smoke channel. We weld the air duct from profile pipe 40×60 mm. A fan will be attached to it through the flange. Air entry is through the rear wall.
6. We weld door hinges and bookmarks for attaching a decorative frame. We wrap the boiler tank with basalt insulation, fix it with a cord. We fix the frame with self-tapping screws to the bookmarks, install the doors.

We install a fan on the air duct, an electronic unit on top of the boiler, and hide the sensor under the insulation.

Mine pyrolysis boiler - device features

Boilers with additional chambers for the complete combustion of gases generated during the combustion process are more efficient than classic long-burning boilers. Gases are released when high temperature and, thanks to the special arrangement of the boiler, they burn out completely, giving additional heat. Firewood is used only very dry, the system does not work on wet fuel. The use of wood pellets allows you to automate their supply.

When starting to manufacture a heating boiler, you should carefully study the diagram, understand the work, familiarize yourself with the working drawings. In any design, you can make some changes that do not concern principle device. Changes are usually associated with external dimensions, connection and are called by specific conditions. We offer drawings of a 40 kW pyrolysis boiler, which can be taken as a basis for self-production.

The diagram shows: A – controller; B - loading door; C - ash pan; D - smoke exhauster; E – sensor installation location; F - connection for installation safety valve; G - hot water pipe; H - protective heat exchanger - cold water; K - heat exchanger - hot water; L - return; M - expander.

To make a boiler, you will need:

sheet metal 4 mm thick;
thick-walled pipe with a diameter of 32 mm, 57 mm, 159 mm;
profile pipe 30 × 60 mm and 40 × 80 mm;
electronic control unit, fan.

The amount of materials is calculated based on the specific dimensions of the product. For greater clarity, consider the view of the body of the pyrolysis boiler from the inside.

At the first test run, we determine the efficiency of the structure, the easiest way to do this is by smoke: if there is no smell carbon monoxide, efficiency is high. Instead of a water circuit, a boiler is sometimes used with air heated. Such a system is beneficial for dachas, where the owners are visiting, and the water in the heating system is threatened with defrosting. Hot air is supplied through pipes, and flows by gravity from the floor. We install the mine boiler on a solid concrete foundation.

Brick and metal option - cheaper and easier

The use of bricks will facilitate and reduce the cost of creating a mine boiler with lower combustion. We make only a heat exchanger from metal vertical type. It can be made

from sheet material;
from sheets of metal with tie-in pipes;
only from pipes.

The pure tube heat exchanger is the most efficient, but also the most difficult to manufacture. The appearance is shown in the figure, the dimensions are selected by the manufacturer.

On a solid concrete foundation, we lay out the blower chamber, install the grate. We put the heat exchanger, we make walls around it from high-quality bricks. When laying, we install two doors. The lower door is placed so that it is possible to set fire to the fuel and clean the firebox and blower from the ashes. You can install two separate doors instead of one large one. The upper door is used to load firewood, coal, it can be placed on the front of the boiler, or on top in the form of a hatch.

The figure below shows general form mine boiler with brick walls.

A few notes on laying brick walls boiler and installation. The thickness of the cladding in half a brick will be sufficient. We set the heat exchanger so that the hot water outlet is at the highest point. This will prevent the creation of air congestion, improve water circulation. The masonry is carried out with dressing of the seams, rises 2-3 cm above the exchanger. We lay out the chimney from brick or install it from metal.

“A boiler is really a stove in a barrel of water” ... and the efficiency of such a unit will be at best 10%, or even 3-5%. Some kind of, but a solid fuel boiler is not a stove at all, and a solid fuel stove is not a hot water boiler. The fact is that the process of combustion of solid fuel, in contrast to gas or combustible liquids, will certainly stretch in space and time. Gas or oil can be completely burned immediately in a small gap from the nozzle to the diffuser of the burner, but wood-charcoal cannot. Therefore, the requirements for the design of a solid fuel heating boiler are different than for heating furnace, it’s impossible to just put a water heater of the heating circuit into it in continuous circulation. Why is this, and how should a continuous heating boiler be arranged, and this article is intended to explain.

Your own heating boiler in a private house or apartment becomes a necessity. Gas and liquid fuels are steadily rising in price, and in return, inexpensive alternative fuels appear on the market, for example. from crop waste - straw, husks, husks. This is only from the point of view of the owners of the house, not to mention that the transition to individual heating will allow to get rid of energy losses in the mains of the CHP and power transmission lines, and they are by no means small, up to 30%

You can’t do a gas boiler yourself, if only because no one will give permission for its operation. It is forbidden to use individual liquid fuel boilers for heating residential premises due to their high fire and explosion hazard in decentralized use. But a solid fuel boiler can be made with your own hands and formalized, just like a heating stove. This is perhaps the only thing they have in common.

Features of solid fuel

Solid fuel does not burn very quickly, and in its visible flame, not all components that carry thermal energy. For the complete combustion of flue gases, a high, but quite definite temperature is necessary, otherwise conditions will arise for the occurrence of endothermic reactions (for example, nitrogen oxidation), the products of which will carry the energy of the fuel into the pipe.

Why doesn't the boiler bake?

The furnace is a cyclic device. So much fuel is loaded into its furnace at once so that its energy is enough until the next heating. The excess combustion energy of the fuel load is partly used to maintain the optimum temperature for afterburning in the gas path of the furnace (its convective system), and is partially absorbed by the body of the furnace. As the load burns out, the ratio of these parts of the fuel energy changes, and a powerful heat flow circulates inside the furnace, several times more powerful than the current heating needs.

The body of the furnace is, therefore, a heat accumulator: the main heating of the room occurs due to its cooling after heating. Therefore, it is impossible to take away the heat circulating in the furnace, because of this, in one way or another, its internal heat balance will be disturbed, and the efficiency will drop sharply. It is possible, and even then not in every place of the convection system, to take up to 5% to replenish the DHW storage tank. Also, the furnace does not need operational adjustment of its thermal power, it is enough to load fuel based on the required hourly average for the time between heatings.

A water boiler, no matter what fuel, is a continuous device. The coolant in the system circulates all the time, otherwise it will not heat up, and the boiler must at any given moment give exactly as much heat as it has gone outside due to heat loss. That is, the fuel must be either periodically loaded into the boiler, or the thermal power must be promptly regulated within a fairly wide range.

The second point is flue gases. They must approach the heat exchanger, firstly, as hot as possible in order to ensure high efficiency. Secondly, they must be completely burnt out, otherwise the energy of the fuel will settle on the register with soot, which will also need to be cleaned.

Finally, if the furnace heats around itself, then the boiler as a heat source and its consumers are separated. The boiler requires a separate room (boiler room or furnace): due to the high concentration of heat in the boiler fire hazard much higher than ovens.

Note: an individual boiler room of a residential building must have a volume of at least 8 cubic meters. m, ceiling not less than 2.2 m high, opening window not less than 0.7 sq. m, a constant (without valves) influx of fresh air, a smoke channel separate from other communications and a fireproof interchange from the rest of the rooms.

From this it follows, firstly, boiler furnace requirements:

It must ensure rapid and complete combustion of the fuel without a complex convection system. This can only be achieved in a furnace made of materials with the lowest possible thermal conductivity, because. Fast combustion of gases requires a high concentration of heat.
The furnace itself and the parts of the structure associated with it in terms of heat should have the lowest possible heat capacity: all the heat that went into heating them will remain in the boiler room.

These requirements are initially contradictory: materials that conduct heat poorly, as a rule, accumulate it well. Therefore, an ordinary furnace furnace for a boiler will not work, some kind of special one is needed.

Heat exchange register

Heat exchanger - the most important node heating boiler, it basically determines its efficiency. According to the design of the heat exchanger, the entire boiler is called. In domestic heating boilers, heat exchangers are used - water jackets and tubular, horizontal or vertical.

A boiler with a water jacket is the same “stove in a barrel”, a heat exchange register in the form of a tank surrounds the furnace in it. A jacketed boiler can also be quite economical on one condition: if the combustion in the furnace is flameless. A fiery solid fuel furnace certainly requires afterburning of the exhaust gases, and in contact with the jacket, their temperature immediately drops below the value required for this. As a result - efficiency up to 15% and increased soot deposition, and even acid condensate.

Horizontal registers, generally speaking, are always inclined: their hot end (supply) must be raised above the cold (return), otherwise the coolant will go back, and failure forced circulation immediately lead to a severe accident. In vertical registers, the pipes are arranged vertically or in a slight slope to the side. Both here and there pipes, so that gases “get tangled” better in them, are arranged in rows in a checkerboard pattern.

Regarding the directions of movement of hot gases and coolant, pipe registers are divided into:

Flowing - gases pass generally perpendicular to the flow of the coolant. Most often, this scheme is used in horizontal industrial boilers. high power for the sake of their lower height, which reduces the cost of installation. In everyday life, the situation is reversed: in order for the register to properly capture the heat, it has to be made stretched upwards above the ceiling.
Countercurrent - gases and coolant move along the same line towards each other. Such a scheme gives the most efficient heat transfer and the highest efficiency.
Flow - gases and coolant move in parallel in one direction. It is rarely used in boilers for special purposes, because. In this case, the efficiency is poor, and the equipment wear is high.

Further, the heat exchangers are fire-tube and water-tube. In fire tubes, smoke tubes with flue gases pass through a water tank. Fire tube registers work stably, and vertical ones give good efficiency even in a flow circuit, because. internal water circulation is installed in the tank.

However, if we calculate the optimal temperature gradient for transferring heat from gas to water based on the ratio of their density and heat capacity, then it turns out to be about 250 degrees. And to push this heat flow through the wall steel pipe 4 mm (less than it is impossible, it will burn out very quickly) without noticeable losses in the thermal conductivity of the metal, about 200 degrees are needed. Eventually, inner surface the smoke tube must be heated to 500-600 degrees; 50-150 degrees - operating margin for fuel water cut, etc.

Because of this, the service life of the fire tubes is limited, especially in large boilers. In addition, the efficiency of a fire-tube boiler is low, it is determined by the ratio of the temperatures of the hot gases entering the register and those leaving the chimney. It is impossible to allow gases to cool below 450-500 degrees in a fire tube boiler, and the temperature in a conventional furnace does not exceed 1100-1200 degrees. According to the Carnot formula, it turns out that you cannot get an efficiency higher than 63%, and even the efficiency of the furnace is not more than 80%, so the total is 50%, which is really bad.

In small domestic boilers, these features are less pronounced, because. with a decrease in the size of the boiler, the ratio of the surface of the register to the volume of flue gases in it increases, this is the so-called. square-cube law. In modern pyrosis boilers, the temperature in the combustion chamber reaches 1600 degrees, the efficiency of their furnace is under 100%, and the registers of branded boilers are made only thin-walled from heat-resistant special steel with a guarantee for 5 years or more. In them, gases can be allowed to cool to 180-250 degrees, and the overall efficiency reaches 85-86%

Note: cast iron for fire tubes is generally unsuitable, it cracks.

In water-tube registers, the coolant flows through pipes placed in a fire chamber, where hot gases enter. Now the temperature gradients and the square-cube law act in reverse: at 1000 degrees in the chamber, the outer surface of the pipes will be heated to only 400 degrees, and the inner surface to the temperature of the coolant. As a result, ordinary steel pipes serve for a long time and the boiler efficiency is about 80%.

But horizontal flow-through water tube boilers are prone to the so-called. "bubble". The water in the lower pipes is much hotter than in the upper ones. It is pushed through to the supply in the first place, the pressure drops, and the colder upper pipes “spit out” the water. "Whipping" not only gives noise, warmth and comfort as much as a neighbor - a drunkard and a brawler, but is also fraught with an impulse in the system due to water hammer.

Vertical water tube boilers do not fill, but if a water tube boiler is designed for the house, the register must be located on the chimney downstream, in the area where hot gases go from top to bottom. In a flow-type, with the same direction of movement of gases and coolant, a water-tube boiler, the efficiency drops sharply and soot is intensively deposited on the pipes near the supply, and it is generally unacceptable to make a return flow above the supply.

About the heat exchanger capacity

The ratio of the capacities of the heat exchanger and the entire cooling system is not taken arbitrarily. The rate of heat transfer from gases to water is not infinite, the water in the register must have time to take in heat before it leaves the system. On the other hand, the heated outer surface of the register gives off heat to the air, and it is wasted in the boiler room.

Too small a register is prone to boiling and requires precise, quick adjustment of the furnace power, which is unattainable in solid fuel boilers. The register of a large volume warms up for a long time and, if the external thermal insulation of the boiler is poor or absent, it loses a lot of heat, and the air in the boiler room can warm up above the permissible temperature. fire safety and specifications for the boiler.

The value of the capacity of the heat exchanger of solid fuel boilers ranges from 5-25% of the capacity of the system. This must be taken into account when choosing a boiler. For example, for heating, according to the calculation, only 30 sections of radiators (batteries) of 15 liters each were obtained. With water in the pipes and an expansion tank, the total capacity of the system will be about 470 liters. The capacity of the boiler register should be in the range of 23.5-117.5 liters.

Note: there is a rule - the greater the calorific value of solid fuel, the greater should be the relative capacity of the boiler register. Therefore, if the boiler is coal, the register capacity should be taken closer to the upper value, and for wood - to the lower one. For slow burning boilers, this rule is not valid; the capacity of their registers is calculated based on the highest efficiency of the boiler.

What is a heat exchanger made of?

Cast iron as a material for the boiler register does not meet modern requirements:

The low thermal conductivity of cast iron leads to low boiler efficiency, because. it is impossible to cool the exhaust gases below 450-500 degrees, as much heat will not pass through the cast iron into the water as needed.
The large heat capacity of cast iron is also its minus: the boiler must quickly give off heat to the system before it escapes somewhere else.
Cast iron heat exchangers do not fit into modern requirements in terms of weight and dimensions.

For example, let's take the M-140 section from the old Soviet cast iron battery. Its surface area is 0.254 sq. m. For heating 80 sq. m. m. of living space you need a heat exchange surface in the boiler of about 3 sq. m, i.e. 12 sections. Have you seen a 12 cell battery? Imagine what a cauldron should be in which it will fit. And the load from it on the floor will definitely exceed the limit according to SNiP, and a separate foundation will have to be made under the boiler. In general, 1-2 cast iron sections will go to the heat exchanger that feeds the DHW storage tank, but for the heating boiler, the issue of the cast-iron register can be considered closed.

The registers of modern factory boilers are made of heat-resistant and heat-resistant special steel, but production conditions are needed for their manufacture. The usual structural steel remains, but it corrodes very quickly at 400 degrees and above, so fire-tube boilers made of steel must be chosen for purchase or developed very carefully.

In addition, steel is a good conductor of heat. On the one hand, this is not bad, you can count on simple means get good efficiency. On the other hand, the return pipe must not be allowed to cool below 65 degrees, otherwise acid condensate from the flue gases will fall on the register in the boiler, which can eat through the pipes within an hour. You can eliminate the possibility of its deposition in 2 ways:

With a boiler power of up to 12 kW, a bypass valve between the boiler supply and return is sufficient.
With a higher power and / or a heated area of more than 160 sq. m, an elevator assembly is also needed, and the boiler must operate in the mode of overheating water under pressure.

The bypass valve is controlled either electrically from a temperature sensor or non-volatilely: from a bimetallic plate with a rod, from wax melting in a special container, etc. As soon as the return temperature drops below 70-75 degrees, it lets in hot water from submission.

The elevator unit, or simply the elevator (see Fig.) acts the other way around: the water in the boiler is heated to 110-120 degrees under pressure up to 6 atm, which eliminates boiling. To do this, the combustion temperature of the fuel is increased, which increases the efficiency and eliminates condensation. And before being fed into the system, hot water is diluted with a return pipe.

In both cases, forced circulation of water is necessary. However, a steel boiler with thermosiphon circulation, which does not require power supply for circulation pump is quite possible to create. Some designs will be discussed below.

Circulation and boiler

Thermosiphon (gravitational) circulation of water does not allow heating a room with an area of more than 50-60 square meters. m. The point is not only that it is difficult for water to squeeze through a developed system of pipes and radiators: if you open drain tap, the water will rush out in a strong stream. The fact is that the energy for pushing water through the pipes is taken from the fuel, and the efficiency of converting heat into motion in a thermosiphon system is scanty. Therefore, the efficiency of the boiler as a whole falls.

But the circulation pump needs electricity (50-200 W), which can be lost. UPS (source uninterruptible power supply) for 12-24 hours of battery life is very expensive, so a properly designed boiler is designed for forced circulation, and in the event of a power outage, it must switch to thermosiphon mode without outside interference, when the heating is barely warm, but still warms.

How is the boiler installed?

From the requirement of the minimum own heat capacity of the boiler, its small weight compared to the furnace and the weight load from it per unit floor area directly follow. As a rule, it does not exceed the minimum allowable according to SNiP for flooring 250 kg / sq. m. Therefore, the installation of the boiler is permissible without a foundation and even parsing the flooring, incl. and on the upper floors.

Place the boiler on a flat, stable surface. If the floor plays, it will still have to be disassembled at the installation site of the boiler to concrete screed with a side extension of at least 150 mm. The base under the boiler is covered with asbestos or basalt cardboard 4-6 mm thick, and a sheet is placed on it roofing iron 1.5-2 mm thick. Further, if the flooring was dismantled, the bottom of the boiler is bricked up cement-sand mortar to floor level.

Around the boiler protruding above the floor, thermal insulation is made, the same as under the bottom: asbestos or basalt cardboard, and iron on it. Removal of insulation to the sides of the boiler from 150 mm, and in front of the firebox door at least 300 mm. If the boiler allows additional loading of fuel until the previous portion burns out, then the removal in front of the furnace is needed from 600 mm. Under the boiler, which is placed directly on the floor, only thermal insulation is placed, covered with a steel sheet. Removal - as in the previous case.

For a solid fuel boiler, a separate boiler room is required. The requirements are listed above. In addition, almost all solid fuel boilers do not allow power adjustment over a wide range, so they need a full-fledged piping - a set of additional equipment that ensures efficient and trouble-free operation. We will talk about it further, but in general the boiler piping is a separate big topic. Here we mention only the immutable rules:

The installation of the piping is carried out in countercurrent to the water, from the return to the supply.
At the end of the installation, its correctness and quality of the connections are checked visually according to the scheme.
The installation of the heating system in the house is started only after tying the boiler.
Before loading fuel and, if required, applying power, the entire system is filled with cold water and during the day they control all joints for leakage. In this case, water is water, and not some other coolant.
If there are no leaks, or after they are eliminated, the boiler is started on water, continuously monitoring the temperature and pressure in the system.
Upon reaching the nominal temperature, the pressure is controlled for 15 minutes, it should not change by more than 0.2 bar, this process is called pressure testing.
After pressure testing, the boiler is extinguished, the system is allowed to cool completely.
Drain the water, fill in the regular coolant.
Once again, the joints are checked for leakage for a day. If everything is in order, start the boiler. No - eliminate leaks, and again daily control before starting.

Choosing a boiler

Now we know enough to choose a boiler based on the intended type of fuel and its purpose. Let's get started.

Wood

The calorific value of firewood is low, for the best - less than 5000 kcal / kg. Firewood burns quite quickly, releasing a large amount of volatile components that require afterburning. Therefore, it is better not to count on high efficiency on wood, but they can be found almost everywhere.

Wood burning in the house

A home wood-burning boiler can only be of long burning, otherwise it beats it in all respects. Industrial structures, eg. well-known KVR, cost from 50,000 rubles, which is still cheaper than building a furnace, do not require power supply and allow power adjustment for heating in the off-season. As a rule, they work both on coal and on any solid fuel, except for sawdust, but on coal, fuel consumption will be much higher: heat transfer from one load is 60-72 hours, and for specialized coal - up to 20 days.

However, a long-burning wood-burning boiler can be useful in places where there is no regular delivery of coal and a qualified heat engineering service. It costs one and a half times cheaper than coal, its shirt design is very reliable and allows you to build a thermosiphon heating system with an area of up to 100 square meters. m .. In combination with the smoldering of fuel with a thin layer and a rather large volume of the jacket, boiling of water is excluded, so the binding is quite the same as for titanium. Connecting a long-burning wood-fired boiler is also no more difficult than titanium, and can be done independently by an unskilled owner.

About brick boilers

Scheme of the device of the boiler "Blago"

Brick is a friend of the furnace and an enemy of the boiler due to the fact that it gives the structure a large thermal inertia and weight. Perhaps the only brick boiler in which the brick is in its place is the pyrolysis "Blago" Belyaev, the diagram in fig. And then, its role here is completely different: the lining of the combustion chamber is made of fireclay bricks. Heat exchanger water-tube horizontal; the problem of coiling is solved by the fact that the register pipes are single, flat, elongated in height.

The Belyaev boiler is really omnivorous, and 2 separate bunkers are provided for loading different types of fuel without stopping the boiler. On anthracite "Blago" can work for several days, on sawdust - up to a day.

Unfortunately, the Belyaev boiler is quite expensive, because of the fireclay lining it is poorly transportable and requires, like everyone else pyrolysis boilers, complex and expensive strapping. Its power is regulated within a small range by flue gas bypass, so it will show good efficiency on average per season only in places with prolonged severe frosts.

About boilers in the furnace

The boiler in the furnace, about which so much is being said and written now, is a water-tube heat exchanger immured in the furnace masonry, see fig. below. The idea is this: the stove after heating should give off heat more to the register than to the surrounding air. Let's say right away: reports of an efficiency of 80-90% are not only doubtful, but simply fantastic. The best brick oven itself has an efficiency of no higher than 75%, and its area outer surface will be at least 10-12 square meters. m. The surface area of the register is hardly more than 5 square meters. m. In total, less than half of the heat accumulated by the furnace will go into the water, and the overall efficiency will be below 40%

The next moment - an oven with a register immediately loses its property. In no case should you drown it out of season with an empty register. The TC (temperature coefficient of expansion) of the metal is much greater than that of a brick, and the heat exchanger swollen from overheating will tear the furnace before our eyes. Thermal seams will not help the case, the register is not a sheet or a beam, but a three-dimensional structure, and it bursts immediately in all directions.

There are other nuances here, but the general conclusion is unambiguous: a stove is a stove, and a boiler is a boiler. And the fruit of their violent unnatural union will not be viable.

Boiler piping

Boilers that exclude boiling water (jacketed long-burning, titanium) cannot be made for a power of more than 15-20 kW and stretched in height. Therefore, they always provide heating of their area in the thermosiphon mode, although the circulation pump, of course, will not interfere. Their binding except expansion tank includes only an air drain cock at the highest point of the supply pipeline and a drain cock at the lowest point of the return.

The piping of solid fuel boilers of other types should provide a set of functions, which is better understood in fig. on right:

safety group: air drain cock, common pressure gauge and breakthrough valve to release steam when boiling;
emergency cooling storage tank;
its float valve, the same as in the toilet;
thermal valve for starting emergency cooling with its sensor;
MAG-block - drain valve, emergency drain valve and pressure gauge, assembled in one housing and connected to a membrane expansion tank;
forced circulation unit with check valve, a circulation pump and a three-way bypass valve electrically controlled by temperature;
intercooler - emergency cooling radiator.

Pos. 2-4 and 7 make up the power reset group. As already mentioned, solid fuel boilers are regulated in terms of power within small limits, and in case of sudden warming, the entire system can overheat unacceptably, up to a gust. Then the thermal valve 4 starts tap water into the intercooler, and it cools the flow to normal.

Note: the master's money for fuel and water at the same time quietly flowing down the drain. Therefore, solid fuel boilers are unsuitable for places with mild winters and long off-seasons.

The forced circulation group in normal mode bypasses part of the supply to the return line so that its temperature does not fall below 65 degrees, see above. When the power is turned off, the thermal valve closes. As much water enters the heating radiators as they let through in the thermosyphon mode, if only it was possible to live in the rooms. But the intercooler thermal valve opens completely (it is kept closed under voltage), and the excess heat again takes the owner's money into the drain.

Note: if water is lost along with electricity, the boiler must be urgently extinguished. When the water from tank 2 flows out, the system will boil.

Boilers with built-in overheating protection are 10-12% more expensive than conventional ones, but this more than pays off by simplifying the piping and increasing the reliability of the boiler: excess superheated water is poured into an open large-capacity expansion tank, see Fig. return line. The system, except for the circulation pump 7, is non-volatile and goes into the thermosiphon mode smoothly, but with a sudden warming, the fuel is still wasted, and the expansion tank must be installed in the attic.

As for pyrolysis boilers, then typical scheme their bindings are given for reference only. Anyway, its professional installation will cost only a small part of the cost of the component. For reference: a heat accumulator alone for a 20 kW boiler costs about $5,000.

Note: membrane expansion tanks, unlike open ones, are installed on the return line at its lowest point.

Chimneys for boilers

Chimneys of solid fuel boilers are generally calculated in the same way as stoves. General principle: too narrow a chimney will not give the desired draft. For the boiler, this is especially dangerous, because. it is heated continuously and the waste can go at night. Too wide a chimney leads to "whistling": cold air it descends into the furnace, chilling the furnace or register.

The boiler chimney must meet the following requirements: the distance from the roof ridge and between different chimneys is at least 1.5 mm, the upward extension above the ridge is also at least 1.5 m. Safe access to the chimney must be provided on the roof at any time of the year. At each break in the chimney outside the boiler room there must be a cleaning door, each passage of the pipe through the ceiling must be thermally insulated. The upper end of the pipe must be equipped with an aerodynamic cap; for the chimney of the boiler, it, unlike the stove, is mandatory. Also, a condensate collector is required for the boiler chimney.

In general, the calculation of the chimney for the boiler is somewhat simpler than for the furnace, because. the boiler chimney is not so winding, the heat exchanger is simply considered a lattice barrier. Therefore, it is possible to build generalized graphs for different design cases, for example. for chimney with horizontal section(pine forest) at 2 m and a condensate collector with a depth of 1.5 m, see fig.

According to such graphs, after an accurate calculation according to local data, it is possible to estimate whether there was a gross error. If the calculated point is somewhere around its generalized curve, the calculation is correct. IN last resort, you will have to build up or cut the pipe by 0.3-0.5 m.

Note: if, say, for a pipe with a height of 12 m there is no curve for a power of less than 9 kW, this does not mean that a 9 kW boiler cannot be operated with a shorter pipe. It’s just that for lower pipes, a generalized calculation is no longer possible, and you need to calculate exactly according to local data.

Video: an example of the construction of a mine-type solid fuel boiler

conclusions

The depletion of energy resources and the rise in fuel prices have radically changed the approach to the design of domestic heating boilers. Now from them, as well as from industrial ones, high efficiency, low thermal inertia and the possibility of operational power control over a wide range are required.

In our time heating boilers according to the basic principles laid down in them, they finally parted ways with furnaces and divided into groups for different climatic conditions. In particular, considered solid fuel boilers are suitable for areas with a harsh climate and prolonged severe frosts. For places with a different climate, other types of heaters will be preferable.

Center heating system in a private house is a heating boiler. It is he who releases energy, which is later converted, enters the coolant and heats the heating radiators. In this article we will tell you how to make a heating boiler with your own hands, how to weld a boiler for heating a private house, and also provide drawings and photo instructions.

Types of heating boilers

Before starting the independent manufacture of the boiler, it is necessary to determine its type, which depends on the type of fuel heated by the coolant. If desired, you can build a boiler that runs on any fuel. Find necessary information available on the Internet. However, before making a choice, it is worth having an idea about the advantages and disadvantages of the most famous of them.

Gas boilers for heating. You should not try to make this type with your own hands, as there are a lot of requirements for them that you are unlikely to be able to satisfy. Well, no less important reason is the high probability of an explosion during operation. The installation of a gas boiler is prohibited in basement Houses.
For the manufacture of electric boiler you do not need professional skills and the availability of many materials. It should be noted a huge drawback - high prices for electricity. This is ideal option for periodic heating of a country house, but for permanent use, an electric boiler is very expensive.
A liquid fuel boiler is quite suitable for do-it-yourself manufacturing, but the cost of fuel and the particular settings of the nozzles can cause considerable difficulties in the course of work.
Among all the options listed, the most optimal can be called a solid fuel boiler, which can be successfully used as firewood.

Everyone knows that firewood has a high combustion rate, and therefore does not have time to heat the room to the desired temperature at the initial efficiency. In order to optimize this process, it is worth considering two ways to independently build solid fuel boilers.

Pyrolysis version of the boiler

A boiler of this type is adapted for burning wood, its additional name is a gas-generating boiler. The essence of his work is that the combustion of firewood and the volatile substances emerging from them is carried out separately. Thanks to the pyrolysis process, such boilers manage to maintain the optimal temperature regime of the heat carrier for a period of 6 to 12 hours without adding firewood.

The operation of the pyrolysis boiler cannot be carried out without electrical energy, which ensures the operation of the fan supporting the combustion process in a forced way.

The dimensions of such structures are 1.5 × 0.75 × 1.7 m. The volume of the water tank is 500 liters with a power output of 50 kW. Installation dimensions can vary according to individual needs.

As a rule, for self-manufacturing of the structure, you will need a steel sheet with a thickness of 4-6 mm, a cast-iron sheet of 1 cm, a steel pipe with a wall thickness of 4 mm, welding electrodes and a welding machine. Also stock up centrifugal fan, a grate that matches the size of the combustion chamber, automatic device for regulation temperature regime, asbestos sheet and sealing cord.

At the end of the manufacturing process, the heating boiler must be tied up with your own hands in compliance with the technological requirements.

Pellet type boiler

This type of boiler plant is more automated and less whimsical in maintenance during operation. Pellets are granulated wood, for the manufacture of which sawdust and shavings are used. Since this material is free-flowing, they are fed into the combustion chamber automatically using an auger, or hopper.

You may have difficulty in the manufacture of such a boiler due to the lack of certain electrical equipment: electric motor to ensure the operation of the auger, or bunker damper.

The operation of the pellet boiler is carried out in such a way that there is no need for kindling or adding fuel. This is affected by the dimensions of the bunker. Thanks to the principle of operation of the boiler plant, it is possible to control the amount of heat generated, due to the amount of pellets fed into the furnace.

These two types of boilers are optimal for handmade. Which one to choose is up to you. This is determined by many factors, the main of which is the need for heat and the availability of a certain type of fuel that you will use.

In any case, it is necessary to strictly follow the technology and observe safety rules.