The appearance on the market of solid fuel boilers with automatic feeding has greatly simplified the lives of many consumers for whom gas or electric heating is not available. The development of production has led to the creation of many models for various purposes. Knowledge of the device, principles of operation and types of automatic units will help to choose the most suitable and profitable option.
Features of boilers with automatic feeding
The elements of the boiler plant, which are directly responsible for the combustion of fuel and the transfer of heat to the heating system of the house, do not differ significantly from conventional solid fuel devices.
The main operational advantage of devices with automatic feeding is provided by the presence of three basic components in their design:
- a fuel bunker for one-time loading of large volumes of combustible materials;
- screw conveyor for regular transfer of fuel to the combustion chamber;
- complex automation responsible for the operation of the entire system.
The listed structural elements provide the possibility of long-term burning without additional maintenance of the boiler plant. For the operation of such equipment, human participation is required no more than 1 time in 1-2 weeks, and sometimes less often.
Automation also regulates the amount of fuel supplied, which depends on the current coolant temperature and set in the settings. When the bunker is almost empty, the system notifies you to fill it up.
Many models also have the ability to automatically remove combustion products. That is, the entire process from ignition to cleaning in such units is carried out without human intervention.
Varieties of designs of solid fuel boilers for long burning
From the information presented above, it is already clear that the main task in operating boilers of such a design is to achieve the correct dosing of air flows: primary air entering the fuel chamber and secondary air, which is responsible for high-quality complete combustion of pyrolysis gases.
In models from different manufacturers, these tasks are solved in different ways. That is, the design of the boilers can be equipped with additional devices that balance the ongoing processes.
Prices for solid fuel boilers
solid fuel boilers
Forced air boilers
One of the design options are boilers with a built-in fan, which is used to force air. The distribution of air flows among the chambers through the internal channels is carried out using an automatic control unit.
Schematic of a long-burning boiler with a built-in fan for air injection
Almost all boilers equipped with fans are arranged so that the main loading chamber is located in the central part of the structure.
Due to the presence of a fan, the fuel quickly flares up, and the heat-resistant materials, which, as a rule, are lined with its inner walls (ceramic concrete or chamotte) accumulate heat well. The thrust created in the firebox constantly supplies the pyrolysis gas released by the fuel to the afterburner, which in some models is even located at the bottom. At the entrance to this space, special ceramic nozzles are installed that can withstand temperatures up to 1000 degrees.
Combustion, pyrolysis gases heat the pipes of the water "jacket".In turn, the circulation pump for heating, installed in the heating circuit and also connected to the automatic unit, provides the required rate of movement of the coolant throughout the entire heating system.
In some models of solid fuel boilers, the afterburner can be located at the rear or top of the boiler structure.
A variant of a long-burning boiler with an afterburner located at the rear of the structure.
If the afterburner is located at the rear of the boiler, it has a rather complex design of heat exchange elements, which contributes to the rapid heating of the coolant. Thanks to this, a high efficiency of the device is achieved, sometimes reaching 90 ÷ 95%.
Such designs of boilers with electronic control have a large number of advantages, but they also have their own significant drawback - this is volatility. In the event of a power outage, the fans, the pump, and, naturally, the entire automatic unit do not function, which leads to the suspension or complete stop of the movement of the coolant along the heating circuit. If power outages are not uncommon for the area where the house is located, then it is necessary to have an autonomous power supply system - this can be an electric generator, which must always be kept in a state of full readiness. From infrequent and not too long interruptions, specially designed UPS - battery uninterruptible power supplies - help.
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Another serious disadvantage of a boiler with an electronic control system is its high sensitivity to voltage drops. Therefore, you have to provide them with protection by installing a separate voltage stabilizer.
Voltage stabilizer - a guarantee of the correct operation of the boiler electronics
You should not spare money on this device - its cost is incomparable with the cost of a boiler saturated with electronics, and skimping with such a precautionary measure can result in much higher costs! How to choose voltage stabilizer for heating boiler - read in a special publication of our portal.
Non-volatile heating devices
To avoid dependence on the stability of the power supply, it is worth choosing long-term combustion units with the organization of natural air draft and equipped with a mechanical control system. There are many such models on the market. For example, these are the familiar domestic boilers or "Trajan".
Solid fuel boiler "Bourgeois-K".
Prices for solid fuel boiler "Bourgeois-K"
Bourgeois-K
These devices have a volumetric fuel chamber located in the lower part of the structure, under which there is a blower, which simultaneously serves as an ash pan. The air damper located at the bottom of the door is connected by a chain to the thermostat.
When igniting firewood loaded into the furnace, it is necessary to open the damper as much as possible to ensure active ignition of the fuel and start the pyrolysis process. To achieve it, a temperature of at least 200 degrees is required.
After the ignition, the flap should be closed, minimizing the access of oxygen to the fuel chamber, transferring the combustion to the smoldering stage. Further, as already described above, pyrolysis gases are released, which enter and ignite in the afterburner.
Thanks to this design, the heating device is completely non-volatile, therefore, even in the absence of electricity, the house will still be supplied with heat.
This type of boilers is inferior in efficiency and fuel economy to volatile appliances, however, it is precisely its independence from the availability of electricity that makes it popular among consumers.In addition, you will not have to pay for energy consumption, which will also help to save on the operation of the heating system as a whole.
Top fired solid fuel boilers
Another design option for heating units is original technological systems with the direction of firewood burning from top to bottom. A similar principle is used not only in many models of solid fuel boilers, but also in furnaces operating on the principle of long burning.
Top-fired boilers are generally cylindrical in shape and placed vertically. Almost all types of solid fuels are suitable for this type of heating units - these are firewood, briquettes, coal, chips, sawdust, etc. The chamber in such boilers has a very large volume, which allows them to operate on one fuel load for a long time: this duration depends on the specific model and type of fuel. For example, some of them are able to work on wood from 24 hours to three days, and when using coal - even from three to seven days.
Solid fuel boiler of cylindrical shape with top burning of a wood-burning bookmark.
The operating cycle of such a boiler can be represented in the following order:
The principle of operation of the boiler with the upper combustion of the fuel tab
So, such a boiler has a cylindrical, vertically located body (item 1).
Through a special door (pos. 2), the selected fuel (pos. 3) is loaded into the chamber. At the very bottom there is a door (pos. 4), which serves to clean the chamber from ash before the next loading.
If firewood is used for heating, large-diameter logs are laid down and in the middle of the bookmark, and chips are loaded around them and on top. Then, with the help of paper, the upper thin firewood is ignited. To ignite fuel, you can use liquids specially designed for igniting furnaces.
In the upper part of the body there is an air supply duct (pos. 5) to the boiler, equipped with a valve. The valve can be manual or semi-automatic, operating on the principle of changing the configuration of a bimetallic plate under the influence of temperature. Air from this channel enters the heating chamber (pos. 6), where it is heated by the heat generated by the boiler.
As soon as the surface burning of the wood begins, a special air distributor is lowered onto the tab (pos. 7). This is a rather massive part of a metal profile, inside of which there are channels for even distribution of air over the surface of the burning fuel. With its weight, the distributor falls on the burning tab, and as it burns out, it gradually descends. For this, it is connected to the air heating chamber with a pipe of a special telescopic design (item 8).
The air heating chamber has a damper (item 9), which regulates the secondary air flow to the upper part of the combustion chamber (item 10).
Pyrolysis gases released during the smoldering of the upper layer of the backfill rise to the upper part of the fuel chamber, where they meet with the flow of hot secondary air entering from above. That is, all the necessary conditions are created for their complete afterburning with a large release of heat. After that, the gaseous waste is discharged through the pipe (pos. 11) into the chimney.
The generated heat is transferred to the boiler water jacket (pos. 12), which is connected to the heating circuit of the system through the return pipes (pos. 13) and supply pipes (pos. 14).
As you can see, in fact, in this design there is no obvious division into a pre-combustion chamber of firewood and final afterburning of gases - the total space is divided into these zones by the position of the air distributor, and the sizes of these zones change during the operation of the unit.
Such models of boilers can be equipped with a built-in fan, which supplies air forcibly. However, even their work can be carried out with only natural thrust. Therefore, the heating of the house will work even in the absence of electricity.
This design has proven to be effective, so some DIYers take it as a basis when creating their own products. A striking example of this is the popular wood-burning stove with the unusual name "Bubafonya".
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Types of boilers by type of fuel bunker
There are two types of loading devices: built-in fuel bunker and mechanized storage. The battery life and the area occupied by the boiler plant depend on which of them the unit is equipped with.
Integrated fuel hopper
Models with a built-in charging device are equipped with a solid fuel container, which is located on the top or side of the main boiler chamber. The advantage of this design is the relative compactness of the heating system. However, in terms of battery life, models with a built-in bunker are inferior to units with a mechanized fuel storage.
Mechanized fuel storage
Here, a separate room or part of a room with a connected fuel supply system acts as a loading device. The volume of such a storage facility is sufficient to accommodate an annual supply of fuel.
The models are distinguished by a sophisticated electronic automatic control system that fully regulates all work processes, as well as the presence of a remote control unit.
Wood-fired boiler with secondary combustion function
After the firewood is ignited in the firebox of the appliance, the emission of smoke begins, which contains flammable gases and small solid particles. In conventional stoves and traditional models of direct fired boilers, all combustion products emitted during this process are immediately removed through the chimney. This is not the best option for two reasons: firstly, the atmosphere is polluted by flue gases, and secondly, the combustible component of the smoke can be used as fuel, while obtaining significant savings. And this became possible after the invention of devices with the function of secondary combustion of combustible gases and the smallest particles of ash contained in the smoke.
Consider how such a wood-fired heating boiler works. A large amount of firewood is loaded into the firebox at once. Primary air is supplied to them from below, from under the grate. After the wood is well lit, the air supply decreases, the combustion intensity decreases, and at the same time the process of generating combustible flue gases is activated. They enter the afterburner, in which a special device evenly distributes the heated secondary air, which helps to ignite them. The combustion of gases occurs almost completely - up to 90% of their initial content in the smoke, since it occurs at a very high temperature - up to 800 ° С. The result is impressive not only because it generates a large amount of thermal energy, but also because carbon monoxide and other harmful chemicals do not enter the atmosphere. Such a long-burning wood-fired boiler with a secondary afterburning function is available in different modifications - some of them can work autonomously, others are equipped with electronic control systems and fans for a stable air supply - these devices, of course, need to be connected to the electrical network.
Connection to heating and water supply networks
A wood-fired boiler with a water circuit can have one or two built-in heat exchangers. In double-circuit models, one heat exchanger is intended for heating, and the second provides the owner with hot water for domestic needs.The height of such devices is usually greater than that of single-circuit devices. Their obvious advantage lies in their increased efficiency due to lower fuel consumption and lower initial costs for purchasing equipment - compared to purchasing a separate water heater and heating device.
The heat exchangers are connected to the pipelines through the corresponding branch pipes on the device body. If forced circulation of the coolant is used using a special pump, then in case of a power outage, an overheating protection system must be provided. For example, an emergency circuit can successfully play this role. The essence of such an adaptation is that in different parts of the system, natural and forced types of circulation are applied simultaneously. In this case, in the absence of voltage in the mains and the pump stops, the gravitational circulation system continues to work, removing heat from the unit and thereby preventing its breakdown. Other protection options are also possible. It is necessary to obtain detailed advice from technical specialists about all the possibilities available in this regard when choosing equipment.
Methods of automatic fuel supply
According to the methods of fuel supply, units with a pneumatic conveyor and auger transmission are distinguished.
The choice of design depends on:
- the degree of noise during the operation of the heating installation;
- power consumption;
- the frequency of fuel delivery to the combustion chamber and other indicators.
Pneumatic conveyor
The combustible materials are delivered to the main boiler chamber by means of air, which is pumped in under pressure. The advantage of such models is that the fuel supply is carried out less frequently. As a result, the system will be able to operate without electricity for a longer time. However, the pneumatic conveyor makes more noise during operation and consumes a lot of electricity - about 1.5–2 kW / h.
Auger transmission
This method is used in most household appliances and is considered the most reliable, but it is not ideal.
Feeding is carried out by means of a screw conveyor, which operates almost silently and consumes less energy - about 80 W / h. The feed rate is automatically controlled.
The use of an auger guarantees the flow of fuel into the boiler, but when its length is more than 2 m, combustible materials are ground into dust.
A small overview of models of solid fuel boilers for long burning
This section will consider several models of solid fuel boilers popular with the Russian consumer, which have proven themselves to be reliable and easy-to-use heating devices.
Solid fuel boiler "Stropuva S40P"
The heating boiler "Stropuva S40P" is a Lithuanian model designed for heating rather large areas and capable of operating on coal, wood, as well as on wood and peat briquettes.
Boilers "Stropuva" immediately stand out from the general background with their characteristic shape
The boiler is of a top firing design and consists of two cylinders, one inside the other. The space between the cylinders is, in fact, a water jacket, that is, a heat exchanger for the heating medium of the heating system. In the inner cylinder there is a volumetric combustion chamber, into which the air supporting the surface combustion of the fuel insert is automatically supplied through a telescopic distributor. As the fuel burns out, the distributor is lowered, creating optimal conditions for its smoldering. In the upper part of the chamber, the final afterburning of pyrolysis gases takes place.
The boiler has a cyclical operation, the fuel is loaded into the combustion chamber manually.
The unit, due to its shape, has compact dimensions in plan, but has a considerable height - 1900 mm. Therefore, the room for its installation must have a sufficiently high ceiling.
The technical characteristics of the Stropuva S40P are determined by the following parameters:
| Parameter name | Indicators |
| Boiler type | long burning solid fuel boiler |
| Fuel type used | firewood, coal, briquettes, "eurowood", pellets |
| Number of contours | one (heating only) |
| power, kWt | 40 |
| Maximum heated area, m2 | 400 |
| Efficiency,% | 85 |
| The presence of a fan for air blowing | there is |
| Built-in circulating pump | not |
| Minimum coolant temperature, ˚С | 60 |
| Maximum coolant temperature, ˚С | 95 |
| Maximum pressure in the heating circuit, bar | 1.5 |
| Primary heat exchanger material | steel |
| Chimney diameter, mm | 200 |
| Thermometer | there is |
| Control type | mechanical |
| Volatility | Yes |
| Safety valve | there is |
| Device weight, kg | 308 |
| Linear parameters (height, depth, width), mm | 2120×680×680 |
The average cost of the device for 2020 is 105,000 ÷ 110,000 rubles.
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Solid fuel boiler "Buderus Logano G221-20"
The Buderus Logano G221-20 model is a German-made solid fuel boiler, which is distinguished by high stability and reliability in operation. The heater can operate on different types of fuel - wood, coal, briquettes and coke. The use of more heat-intensive fuels is permissible, since the boiler is equipped with a cast-iron heat exchanger.
The Buderus Logano G221-20 boiler accepts almost all types of solid fuels
The features of the solid fuel boiler "Buderus Logano G221-20" include the following points:
- Large loading volume of the fuel and ash chamber.
- The possibility of reinstalling the firebox door to the other side - sometimes it is necessary to do this for the comfort of operation.
- Easy access to cleaning the furnace and blower space.
- This boiler model can be easily integrated into an existing heating system, for example, as a backup heating source.
A whole line of Buderus solid fuel heating devices of the Logano G221 series with different technical characteristics is supplied to the Russian market. Therefore, one can choose from them a unit that has the required power for heating both for a residential and industrial building.
Specifications "Buderus Logano G221-20" are as follows:
| Parameter names | Indicators |
| Boiler type | long burning solid fuel boiler |
| Fuel type used | firewood, briquettes, "eurowood", coal, coke. |
| Number of contours | one (heating) |
| power, kWt | 20 |
| Maximum heated area, m2 | 200 |
| Efficiency,% | 78 |
| Coke consumption, kg / h | 3.9 |
| Coal consumption, kg / h | 3.6 |
| Firewood consumption, kg / h | 5.6 |
| Maximum coolant temperature, ˚С | 90 |
| Maximum pressure in the heating circuit, bar | 4 |
| Primary heat exchanger material | cast iron |
| Chimney diameter, mm | 150 |
| Thermometer, pressure gauge | there is |
| Control type | mechanical |
| Volatility | Yes |
| Device weight, kg | 210 |
| Linear parameters (height, depth, width), mm | 1370×820×605 |
The average cost of such a device for 2020 is 110,000 ÷ 115,000 rubles.
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Solid fuel boiler "Protherm Bober 50 DLO"
Protherm Bober 50 DLO is a Slovak-made long-burning boiler made of cast iron. The device is designed for heating both residential and industrial buildings.
Massive, reliable cast iron boiler "Protherm Bober 50 DLO"
The efficient operation of the heater is guaranteed with a high-quality installation, as well as with regular maintenance throughout the entire period of operation. The Protherm Bober 50 DLO boiler is designed to operate in a system with both natural and forced circulation of the heat carrier. Therefore, this model may well function even in the absence of power supply.
Thanks to the cast-iron heat exchanger, the sections are heated evenly, which increases the boiler efficiency up to 90%.
A cooling circuit is provided in the housing, which prevents the temperature of the coolant from rising above 110 degrees.
Foil-clad mineral wool is used as insulation of the casing, which contributes to an increase in the heat capacity of the unit and the safety of its operation.
The design is simple, and such a boiler is capable of operating in a heating system with natural circulation of the coolant in the absence of a source of electricity.
The device is equipped with a special thermostat, the regulator of which is located on its lid. The required temperature is set manually.
Technical characteristics of "Protherm Bober 50 DLO" are shown in the table:
| Parameter names | Indicators |
| Boiler type | long burning solid fuel boiler |
| Fuel type used | firewood, briquettes, "eurowood", coal. |
| Number of contours | one (heating) |
| power, kWt | 35 |
| Maximum heated area, m2 | 265 |
| Efficiency,% | 90 |
| Maximum coolant temperature, ˚С | 85 |
| Minimum coolant temperature, ˚С | 30 |
| Maximum pressure in the heating circuit, bar | 4 |
| Primary heat exchanger material | cast iron |
| Chimney diameter, mm | 150 |
| Thermometer, pressure gauge | there is |
| Control type | mechanical |
| Volatility | not |
| Device weight, kg | 380 |
| Linear parameters (height, depth, width), mm | 935×740×440 |
The average cost of the device for 2020 is 95,000 ÷ 105,000 rubles.
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Solid fuel boiler of long burning "Teplodar Kupper OK30"
The unit, produced by a domestic manufacturer, is especially popular for use in private residential buildings with a small area. Its demand is explained not only by its high technical characteristics, but also by its affordable price.
The Teplodar Kupper OK30 boiler is popular due to its good performance and quite affordable cost
"Teplodar Kupper OK30" has compact dimensions, so it does not take up much space, and you do not have to build a separate spacious room for it. The device is capable of effectively heating the coolant already after 20 minutes from the beginning of the furnace, which ensures that a comfortable temperature in the rooms is achieved in a short time. The advantage of this heating unit is also the fact that it can run on any solid fuel, and if necessary, it can also be converted to electricity or natural gas - it is possible to install standard modules.
In practice, it has been verified that the optimum long life on one tab of this model is achieved when using two types of fuel simultaneously. For example, firewood is first laid horizontally in the combustion chamber, they are ignited, and then coal is filled in through the upper loading channel.
Technical characteristics of "Teplodar Kupper OK30" are summarized in the table:
| Parameter names | Indicators |
| Boiler type | long burning solid fuel boiler |
| Fuel type used | firewood, briquettes, "eurowood", coal. |
| Number of contours | one (heating) |
| power, kWt | 30 |
| Maximum heated area, m2 | 300 |
| Efficiency,% | 90 |
| Water circuit volume, l | 50 |
| Maximum coolant temperature, ˚С | 95 |
| Minimum coolant temperature, ˚С | 30 |
| Maximum pressure in the heating circuit, bar | 2 |
| Primary heat exchanger material | steel |
| Chimney diameter, mm | 150 |
| Thermometer, pressure gauge | there is |
| Control type | mechanical |
| Volatility | not |
| Device weight, kg | 145 |
| Linear parameters (height, depth, width), mm | 1000×645×420 |
The average cost of the device for 2020 is 24,000 ÷ 30,000 rubles.
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Pellet automatic units
One of the most common types of heat generators is wood pellet systems. The principle of operation of pellet boilers is in many ways similar to other automatic units, but there are also characteristic features.
If you trace the similarities and differences, as well as the advantages and disadvantages of such models, it will be easier to choose the appropriate option.
Principle of operation
The basic design of pellet systems is no different from other common automatic heat generators. The fuel bunker is loaded with combustible materials, from where they are gradually poured onto the auger conveyor. The shaft transfers the pellets to the combustion chamber, where the heating agents are heated.
Differences in work can be traced at the stage of fuel supply:
- After starting the auger, the mechanism directs the pellets first into a flexible hose or plastic tube, which dumps the pellets into the dispenser.
- In the metering device, the second shaft measures the required portions of fuel and transfers them to the petal valve.
- The shutter opens and the pellets are dumped onto the third auger, which transfers the measured amount to the firebox.
The described algorithm may vary slightly depending on the implementation of a particular model.
Benefits
The economic and operational benefits of pellet heating systems are mainly related to the advantages of the type of fuel used.
Wood pellets are not inferior to traditional combustible materials in terms of calorific value, but they have a number of advantages:
- lower cost;
- economical consumption, which leads to a longer operating time without additional loading;
- increased environmental friendliness;
- the minimum amount of combustion products in the ash pan.
As for the advantages of the boilers themselves, as a rule, they are smaller in comparison with units operating on other types of fuel.
disadvantages
In addition to the listed advantages, there are also disadvantages.
Since the flame in most pellet models has a horizontal direction, overheating of the boiler structural elements may occur. In addition, the efficiency and power of such equipment is lower.
Types of boilers and principle of operation
As soon as the first long-burning wood-burning boilers for heating a house appeared, skeptics unanimously began to say that the combustion process is constant and cannot be "stretched" over time. And even if you imagine that this will happen, then this is not so much the advantage of the boiler itself as the advantage of the volume of its tank. In fact, long-burning wood-burning boilers, ill-wishers continued their criticism, provide power purely due to the volume of the raw material tank.
Modern long-burning boilers can keep a constantly high temperature in the heating system without additional fuel loading from 12 hours to several days.
Let's figure out in detail what is the principle of operation of boilers of this type, and how this type of boiler actually differs from a conventional wood-burning boiler for heating a private house, except for the impressive volume of the tank for loading.
The principle of operation of a conventional stove is similar to burning a fire.
An ordinary stove is a fire covered in a metal box. A blowing is organized from below, the flame flares up, the firewood crackles together, a considerable amount of heat and steam is released, which flows through the pipes. It got cold, threw wood, and everything is fine and good again. But it's expensive.
Bonfire in an ordinary oven
The operation of a long-burning boiler is based on a pyrolysis scheme, or a process that involves the use of unaccounted heat generated by glowing coals. From the course of physics with chemistry in grade 8, we know that in the process of smoldering certain types of wood in large quantities, carbon monoxide and carbon dioxide are emitted into the atmosphere. Any gas is a great source of pace. The capacities of long-burning boilers make it possible to heat a house without additional fuel loading for up to 7 days.
Automatic wood chip and coal boilers
This option of automatic units should be preferred by residents of regions where the cost of coal is comparable to the price of pellets. Otherwise, their operation will be more expensive.
The main advantage lies in higher efficiency rates. However, coal gives off a significant amount of soot and tar, which leads to less environmental friendliness. Maintenance of equipment is performed more often, as more ash is released during combustion.
For coal-fired boilers, there is a requirement for the size of the pellets of combustible material: from 4 to 25 mm in diameter. This is necessary for the smooth operation of the auger conveyor.
disadvantages
Of course, solid fuel boilers are not without some disadvantages. If you buy cheaper equipment, you will need to throw firewood into it every 2-4 hours. Therefore, you cannot leave him unattended. In addition, you need a place to store fuel, such as woodpiles or special sheds.
Heating wood boilers for the home are sensitive to the quality of the fuel - the wood must be absolutely dry, otherwise the efficiency of the device will almost halve. Of course, high-tech equipment, equipped with automation for fuel delivery and temperature control, can cope with such a problem. However, it is quite expensive.
Let's consider in more detail the main types of wood-burning boilers based on the price factor.
Selection recommendations
The choice of the most suitable model depends on many factors. First of all, you need to decide on the type of fuel, the prices for which may differ depending on the region.
After that, it is worth calculating the area that is available for the installation of the boiler system, and taking into account the wishes for the autonomous operation time. This will help to determine the most acceptable boiler dimensions and the capacity of the fuel bunker, which will significantly narrow the search.
To fully exploit the potential economic and operational benefits of automatic boilers, when choosing, you need to pay attention to the following parameters:
- boiler power (must correspond to the area of the heated room);
- the presence of economical modes;
- exactingness to the quality of fuel, its ash content;
- reliability and safety of long battery life;
- reproducible noise in various modes;
- the presence of the function of automatic ignition and ash collection;
- consumed electricity;
- the ability to operate from rechargeable batteries;
- the size of the ash collection bin and the convenience of its cleaning;
- efficiency of work with different types of fuel pellets and in different modes;
- the presence of a remote control or the ability to additionally connect it.
You also need to pay attention to the appearance of the boiler, including the quality of the welds.
How a modern wood-fired boiler works
It depends on whether we are talking about the so-called non-volatile, or traditional models, or about new products that, to one degree or another, may require electrical energy to operate.
The main part of traditional models is a firebox made of cast iron or steel, enclosed in a body made of the same materials. Such a wood-fired boiler for combustion uses air entering the firebox through the blower, therefore a damper is made on the door, opening which you can increase the air supply or, conversely, reduce it. In order not to be constantly on duty at the boiler, a mechanical regulating device is installed on its upper plane or on the side, connected by a chain with a damper. The main element of this device is an immersion sleeve in contact with the coolant in the water jacket (heat exchanger) of the unit. The sleeve is filled with a substance that expands when the temperature in the system rises and decreases in volume when it decreases. After reaching the set temperature, the device is triggered by raising or lowering the chain by means of a lever and thereby opening or closing the damper.Thus, wood-fired boilers with a water circuit are able to automatically maintain the set temperature in the network, without the need for electricity.
As for the autonomy of the system with such a unit as a whole, its presence or absence will depend on whether the owners have chosen a natural or forced way of circulating the coolant. In the natural method, the coolant moves through the pipes due to its expansion when heated - while the force of gravity forces the cooled liquid, which has a higher density, to go down and return to the heat exchanger for heating. The forced method of moving the heated coolant through the pipes assumes that a circulation pump is installed in the system - it is obvious that here you cannot do without connecting to the electrical network.
Loading fuel into traditional devices, as well as cleaning them from ash, is carried out manually. Any wood fuel can be used in them, as in newer models. Most often these are logs familiar to everyone, but you can also burn pressed briquettes from wood waste, and even pellets - small granules from woodworking and agricultural waste. It can be sawdust, sunflower seed husks, nutshells, and the like. True, to burn pellets, you will have to purchase a special metal basket with small holes, which is placed in the firebox on the grate.
Fully autonomous wood-fired heating boilers are needed by people living in places where there is no gas. Electric heating is known to be expensive, so few people use this type of heating as the main one. But, even if the house has a gas heating device, an autonomous wood-burning boiler will be useful to the owners as a backup - in case of a malfunction of the main device or interruptions in the supply of gas and electricity.
Review of the best manufacturers and prices
Many models of heating units are available to the modern consumer. It is rather difficult to make a choice in such a situation. Understanding popular models and manufacturers will help simplify things.
Germany
German-made boiler equipment is a quality standard. The models have a high level of efficiency and operate without failures. It is not surprising that the systems made in Germany have the highest cost, about 450-600 thousand rubles.
First of all, it makes sense to pay attention to heating systems Buderos, Heiztechnik and ThermoFLUX.
Prices for solid fuel boilers Buderos
solid fuel boilers Buderos
Italy
Among the models of Italian production, there are many universal options. For example, the Lamborghini Ecologik series boilers can operate on wood, coal, peat and briquettes. And after installing additional equipment (adapter door, pellet burner, auger and bunker), pellets are also suitable as fuel.
Italian models are of the middle price category. Marketed brands: Lamborghini, D'Alessandro Termomeccanica, Faci.
Prices for solid fuel boilers Lamborghini
solid fuel boilers Lamborghini
Turkey
Turkish boiler plants belong to the middle price segment. They have an automatic feeding system of good quality and are equipped with a convenient control panel. One of the most popular manufacturers is Totem, which produces silent boilers with simple temperature control. Also known are the brands Emtas and Termodinamik.
Russia
Russian automatic boilers are in constant demand in the domestic market. Manufacturers have achieved significant success thanks to the introduction of modern design methods, new manufacturing technologies and continuous improvement of structures.
The models have an attractive appearance, high-quality assembly, good automation and benefit in terms of price. Their cost starts from 80-100 thousand rubles, which is relatively inexpensive in comparison with imported counterparts.The most famous brands: Danko, Pereko, Obshchemash Peresvet, Obshchemash Valdai, NMK Magnum.
Japan
Japanese products are characterized by a high degree of automation. Many additional built-in functions greatly enhance the usability. Also, the models are distinguished by an ergonomic shape and high-quality materials for manufacturing, as a rule, steel with anti-corrosion treatment.
Prices for Japanese-made automatic solid fuel boilers are not inferior to the cost of models from Germany. Most popular brands: Kentatsu, Rinnai.
Prices for solid fuel boilers Kentatsu
solid fuel boilers Kentatsu
Serbia
The Serbian manufacturer Radijator produces universal, highly environmentally friendly units that are equipped with an overheating protection system and are resistant to ash deposits. Allow you to get an efficiency of about 90%. Pass a mandatory quality check.
China
Most Chinese products are not of high quality and reliability. The exception is the units of the Chinese brand Roda (Turkey is usually the country of origin). The design of the models allows for easy cleaning of the flame tubes, which maintains high combustion efficiency. The average cost of such equipment is 150 thousand rubles. Study the best radiators for an apartment at the link.
Advantages and disadvantages
A wood-fired heating boiler is an excellent alternative to other types of heating equipment. It is expensive to heat with electricity, heating with diesel fuel or working off is also not without its disadvantages (although there are advantages). Therefore, just such a design should be chosen as the cheapest option for organizing heating. We install it in the boiler room, install pipes around the house, install radiators, throw firewood into the firebox and enjoy the warmth.
Let's now see if everything is so good. And we will start by describing the advantages, against the background of which the disadvantages will dazzle. Main positive features:
Firewood is a fairly cheap type of fuel, but very whimsical. Only logs that are very dry and not eaten by beetles can give a good and high-quality heat.
- Cheapness of heating - we are talking about the fact that fuel for such boilers is quite inexpensive. And if possible, you can collect it for free in the nearest forest - in order not to have problems with the law, pay attention to the fallen trees, which will be an excellent source of firewood;
- You do not need permission to install equipment - the same gas boilers need to be connected to the mains, registered with the controlling services, and paid for annual maintenance. In other words, there is a lot of trouble;
- Easy to operate - you just need to kindle the flame, and then the process will go on its own. You just should not forget to throw all new portions into the insatiable firebox;
- Safety - unlike gas or electrical equipment, they are characterized by increased safety.
There are also disadvantages:
- The wood-burning boiler needs constant supervision - you need to control the temperature in the circuit and put firewood. Fast burning of firewood is a key drawback, but is eliminated by choosing a boiler with a large combustion chamber (or pyrolysis unit);
- Expensive equipment - a structure made of cast iron, resistant to corrosion and heat loads, will be expensive. As an alternative, cheaper steel units can be considered, but they do not differ in reliability and long service life;
- To store firewood, you will have to build a woodpile - it will take up a lot of space;
- Difficulty in automation - the problem is solved by using pyrolysis wood-fired boilers with large combustion chambers and systems for adjusting the intensity of combustion;
- The peculiar smell of haze in the rooms - it cannot be said that it is unpleasant, but some people do not like it;
- The need for a separate ventilated room under the boiler room - you cannot put it in a common room;
- Bulky - for small houses you can find a mini format, but most of them are large in size. Yes, and they are mounted only on the floor, while individual gas and electrical units are neatly located on the walls, without taking up unnecessary space.
Thus, wood-fired boilers also have negative features.
In order to ensure complete safety, it is necessary to install the boiler on a sheet of non-combustible material.
Installation requirements for an automatic solid fuel boiler
Despite a lot of advantages, solid fuel boiler plants have important disadvantages. Among them is insufficient fire safety, since sparks are emitted during the combustion of fuel, and the ambient air in the room is very hot.
Photo source: barrakuda.com.ua
To reduce the risk of ignition, it is necessary to take into account a number of requirements for the installation of an automatic unit:
- For any solid fuel boiler, you need to equip a special room - a furnace area of at least 7 m².
- A powerful ventilation system must be provided in the boiler room, because large amounts of oxygen are needed to keep the equipment running smoothly. Experts recommend that the diameter of the outlet and inlet holes in the ventilation shaft be at least 100 mm.
- For walls, flooring and ceilings, non-combustible materials (cement, tiles, plaster) must be used.
- It is better to install the boiler unit in such a place in the furnace so that at least 50 cm of free area remains around it. In this case, you can conveniently maintain and configure the system.
The middle price segment of wood-fired heating boilers for a private house
Boilers from domestic manufacturers, as well as products from Germany, Lithuania, Poland, the Czech Republic and Slovakia, are presented to the buyer in the middle price segment. You can purchase a steel boiler for water heating on wood, the efficiency of which will reach 90%. Cast iron boilers are also found in this segment. Typically, their hulls are made up of whole sections, making it easy to assemble equipment on site. This design also simplifies the repair process by simply replacing the section.
Among the advantages of cast iron housings is their resistance to any kind of corrosion, which significantly extends the service life of the equipment. Nevertheless, cast iron is quite fragile - it does not withstand mechanical damage and temperature changes. Therefore, cold firewood cannot be loaded into a cast iron boiler.
As for steel, it is not afraid of mechanical damage and temperature changes. And provided that certain substances are added to the coolant, it will not be afraid of oxidation either. The main disadvantage of a steel boiler is that the steel burns out quickly. When choosing a boiler, make sure that it is made of heat-resistant metal.
When selecting the capacity of the equipment, it is worth leaving a margin of 25-30%. The fact is that the standard power value of 1 kW per 10 m2 is quite approximate and is applicable only for a pre-heated house with good thermal insulation. In addition, if a wood-fired steam heating boiler does not work at the power limit, then it will last much longer.
The principle of operation of automatic coal boilers
It is important to understand the structure and principle of operation of modern automated boilers without even having an interest, because this knowledge will help to determine the model. In order for the coal-fired boiler and the heating system and hot water supply based on it to operate for a long time autonomously, the following processes must be automated safely and cost-effectively:
- loading portions of coal or other fuel;
- ash removal from the combustion zone into the storage;
- the air supply from the blower fan to the burner must be regulated;
- the temperature in different rooms corresponded to the set one;
- underfloor heating as specified;
- hot water is available at all points of analysis;
- circulation pumps and mixing valves correctly direct the heating medium and warm water.
The user's function is to select the operating mode (setting priority or schedule), either the heating medium temperature or the temperature in each room. Dynamic processes depending on weather changes, water consumption, fuel quantity and quality, air intake are monitored and interpreted by the processor. A full set of options for an automatic coal boiler is expensive, so often only the most laborious processes are automated: fuel loading and air blowing.
The organization of automatic feeding with the help of a screw, the most typical device for modern models.
The principle of operation of the boiler itself has not changed: through the blower, oxygen enters the burning coal, supporting combustion, the exhaust gases go into the chimney. Thermal energy heats up the coolant in the container around the burning coal, and the medium goes through pipes to the radiators. Having given off heat, the liquid returns to the boiler for heating.
There are two options for burning coal:
- Classical... Coal is burned, and pyrolysis gases are released into the atmosphere.
- Pyrolysis... The exhaust gases are saturated with oxygen and burned out, thereby increasing the efficiency of the boiler and increasing the burning time of one portion of coal at least twice, but the cost of pyrolysis models is also at least twice as high.
Structurally, the boiler is also traditional. In classic coal combustion, one furnace, coal burns on the grate, air is supplied from below in a natural way, its level is regulated by the blower door, the exhaust gases are regulated by the chimney damper. The boiler body, which is also a container with a coolant, is surrounded by burning coal. In the pyrolysis version, a forced air supply system is placed above the classic firebox for afterburning gases and solid particles in them, therefore such a well-functioning boiler does not smoke.
There are many implementations of coal-fired boilers with different levels of automation on the market.
Fuel supply system
The most time-consuming and rather dirty business when operating coal-fired boilers with an automatic feed is loading fuel into it. By automating this process, you can already ensure that the bunker is filled no more than once a week. If the budget allows automating the supply of coal to the boiler bunker from a seasonal warehouse, this will make life in the house comfortable for the entire heating period.
An example of organizing auto-feeding into a bunker from an external warehouse in a basement boiler room. However, such systems are not sold ready-made or even modular.
In coal-fired boilers, two types of designs for the automatic coal supply system were obtained: auger and drum type.
A hopper with coal for loading a pyrolysis (and often classic) boiler is installed on the side of the boiler. At the bottom, the box is equipped with an auger that rotates by an electric motor at the command of a computer when operating in automatic mode or from a button in manual mode. The duration of the engine operation is set by the computer, thereby determining the portions of coal loaded into the boiler. At the same time, boost is switched on to control the combustion process.
A boiler with such automation maintains high efficiency with nominal power fluctuations from 30% to 100%, with filling the bunker up to 1 time per week, effectively working out changes in the weather and user settings. Filling the hopper with high quality coal (grain size from 5 mm to 25 mm), depending on the model, is necessary once a week.
In boilers of classic combustion, the coal hopper is often placed above the boiler and automatic loading takes place using a drum (rotating grate). It, rotating around its own axis, delivers a portion of solid fuel to the furnace. After burning out, slag and ash fall into the accumulator. In this case, the requirements for fuel are lower, and there are many specific design solutions for the automation of such boilers.
Ash removal
The second unpleasant procedure after loading coal into the bunker is the removal of slag, caked crust and cleaning of the accumulator from ash.If the boiler is not tied to a conveyor with a seasonal fuel storage, it is desirable that both procedures take place with the same cycle - once a week. Self-cleaning models still require attention, but every 4-6 weeks.
The system of automatic ash removal into an external box is quite simple, but it is not easy and not cheap to organize it, therefore it is a great rarity in coal models.
The amount of ash in the storage is directly influenced by such quality of coal as ash content. Direct combustion boilers are not too demanding on the quality of fuel and can even be fired with household waste. But ash removal will have to be done more often, and the declared characteristics can be given on coal with a moisture content below 30% and an ash content of less than 25%.
Pyrolysis boilers, in addition to a low humidity of up to 20% and an ash content of less than 15%, also require a certain size of coal fractions from 5 mm to 25 mm. Deviation from these requirements reduces the performance of the unit and increases the amount of ash. Some of the unburned coal can be reused after sifting the ash of the accumulator
Automatic ignition of boilers using liquids, removal of ash from their accumulator not manually and self-cleaning of burners can be offered as additional options to very expensive boiler projects and are quite rare. It is not worth counting on a self-cleaning system in coal models, unlike pellet models.
