Boiler long burning on wood can be built according to two different principles. There are equipment in which fire spreads from top to bottom. Due to the gradual burnout of one layer after another, the total time from one bookmark to another increases significantly. The second technology is pyrolysis decomposition. Here, the gases that were released during the burning of firewood are not sent to the pipe, but are ignited again. This technology allows you to get the maximum heat.
Upper combustion principle
The main difference from classic units is that firewood does not burn from below, but from above. The air supply is also carried out from above, moreover, directly into the combustion zone, and not through the grate from below. Such boilers are mostly non-volatile. And this is their big plus. But the work is cyclical: until the entire bookmark burns out, it is impossible to add a new one: the temperature drops, the whole process is disrupted. This is not always convenient. There are other disadvantages as well.
Advantages and disadvantages
The advantages include the ability to control the intensity of combustion, by increasing / decreasing the flow of air into the furnace. If the control is manual, the boilers are non-volatile. It makes sense to install them in a system where there is no circulation pump (). But a decrease in the intensity of combustion greatly affects the efficiency of the boiler (it decreases).
Despite its name, such a boiler does not work on wood for too long: 6-8 hours. Although there are manufacturers who claim that the boiler will burn up to 30 hours on one tab of firewood. In particular, Lithuanian boiler manufacturers Stoptuva say so. In its pure form, it is very difficult to achieve such a result, in any case, in the reviews we saw only 14-24 hours, and not 30 at all.
The disadvantages of upper combustion boilers include exactingness to the quality of fuel: if raw firewood is loaded, the efficiency of the boiler is significantly reduced.
Humidity of 13-20% is considered optimal, firewood containing 30% moisture is acceptable. When using even more raw heat, there will be little. In some situations, it can fade completely. Also, when raw wood is burned, a large number of ash and soot. Therefore, it is often necessary to clean the stove and chimney often.
Homemade boiler "Bubafonya" uses this method. The design is very simple and affordable. It can be easily made from a gas cylinder, a steel pipe or a tank. T.
Pyrolysis and gas generating boilers
The work of this kind of wood-fired boilers is based on the phenomenon of pyrolysis: if firewood burns with a lack of oxygen, they emit a large amount of gases. Almost all of them are flammable. Moreover, when they are burned, much more heat is released than when wood is burned. As a result of the pyrolysis process, it also forms, which exceeds the calorific value of firewood by 2.5 times.
Gas-fired boilers are called so precisely because of the fact that at a high combustion temperature and a lack of oxygen, a lot of gases are formed. They seem to be generated. To release the maximum amount of heat, the combustion temperature of firewood must be above 700 o C. In some models, it reaches 1200 o C.
To fully use all the energy that these gases can give out, they are additionally heated. Then mix again with air and ignite again. This process takes place in the second combustion chamber, which is also called the afterburner.
Varieties
Depending on where which chamber is located, pyrolysis boilers come with an upper or lower afterburner chamber. The most common boilers with a lower location of the second furnace. With this design, it is convenient to bookmark firewood. In this case, the burnt gases are discharged into the hole located below. In this way, the coldest part of the air is removed from the furnace (it is known that the cold air is at the bottom).
It seems that everything is logical. But it will be necessary to clean the furnace much more often: the ash from the upper chamber falls down, clogs the “pyrolysis” chamber. In addition, it will be necessary to create additional traction in the lower part, since the smoke itself will not move down.
Less common are designs with a top-mounted camera. Here it is easier with traction: the smoke itself tends upwards and additional traction is not needed.
However, such a boiler has some features: it is necessary to take energy from the heated air to the maximum. To do this, a labyrinth is arranged at the top of the firebox. Passing through it, hot air transfers heat to the metal from which the labyrinth is made. From it, the air is already heated (with the air heating method), or the coolant (when using water heating). This design leads to an increase in price: a lot of metal is required for the manufacture of a labyrinth, and its quality must be high in order to ensure long-term operation with high temperatures Oh.
Advantages and disadvantages
Gas generating (pyrolysis) boilers have both advantages and disadvantages. The advantages include the fact that the fuel in them burns absolutely, almost without residue. The features of the process allow it to be almost completely automated: all human participation in automatic boilers comes down to filling fuel and periodically cleaning it.
Automation makes it possible to regulate the intensity of work, fuel consumption. You can adjust the work according to the temperature of the air outside. There are special external sensors for this. You can adjust the temperature of the coolant (for water heating).
The negative point is that the system is volatile: no electricity - no heat. To solve this problem and additionally protect the automation from power surges, you can install it, complete with rechargeable batteries, to give several hours of operation after a power failure.
A fairly significant advantage is that not only firewood can be used for the gas generation process. Wastes from sewing, furriery and textile industries are suitable. But how "omnivorous" the boiler needs to be checked with the manufacturers. Usually all boilers of Russian or Ukrainian production are burned out. Some imported models that are optimized for our realities may please, but such models are rare. But you can use any and without restrictions (except for pellets, which simply fail in non-specialized equipment).
The disadvantages include high requirements for the quality of firewood, because if the moisture content of the available fuel exceeds 20%, the boiler has every chance to go out. When laying wet fuel, it is likely that the return to normal temperatures will be difficult and lengthy. The room will cool down during this time.
Almost all models of gas-generating boilers use forced draft during operation, for which an air pump is provided in their design. This means that you need to provide a guaranteed power supply. Power supply is also required for automation.
If your heating main is long enough and the coolant has time to cool before returning back to the boiler, you will have to use a bypass to mix hot water into the return pipe. If this is not done, the primary chamber may go out due to the low temperature of the coolant. And, of course, one of the main drawbacks is the considerable price of pyrolysis boilers.
Classification by heating method
Like any boilers, there are two ways to heat rooms: directly by heating the air and through heating the coolant.
Boilers for direct air heating rarely used in residential areas. Only as backup or emergency heating. The advantages of such equipment are the absolute absence of additional communications, complete independence from gas, electricity and other external factors.
Installation is very simple: only a non-combustible base is required and (if there are such in the immediate vicinity - less than 1.2 m from the furnace). A chimney is also needed to remove combustion products from the room. That's the whole setup.
Since such furnaces are distinguished by a simple design, their demands on fuel quality are also lower. Anything but firewood can be used as fuel:
- peat briquettes;
- seed husks;
- coal;
- household waste;
- wood waste, chips, sawdust;
- paper, cardboard;
Well proved for air heating the furnace-heater Buleryan (Bullerjan). The Bullerjan oven is a solid metal "barrel" surrounded by hollow pipes. The pipes are tightly pressed (welded) to the body. They heat up instantly, with almost no heat loss. The lower ends “suck in” cold air, and through the upper ends it comes out already warm. This design contributes to the rapid heating of the room: it begins immediately after kindling.
Quickly heat up the air in the room. Works on the principle of convection
"Buleryan" is arranged from two combustion chambers, works on the principle of "clean combustion". The temperature of the synthesis gases at the outlet is 250–300 o C, and the efficiency reaches 80–85%. At the same time, the temperature of the oven itself remains quite low, and the tight closing of the door ensures compliance with all sanitary control standards.
The second type is wood-fired boilers with a water circuit. They have a heat exchanger inside, the dimensions of which and the performance are calculated depending on the power of the equipment. This equipment has a completely different design. Their main task is to quickly heat the coolant, with the help of which heat will be carried around the room. Most often, the heat exchanger is located around the entire perimeter of the furnace, removing the maximum amount of heat from its walls. Such boilers are also called hot water boilers.
Most modern wood-fired boilers have just this way of organizing heating. When buying wood-fired hot water boilers, you need to pay attention to such a characteristic as the maximum volume of coolant in the system. You need to take a unit with a small margin in terms of performance: constant work at the limit of possibility reduces the lines of operation, and in case of expanding areas it is better to have at least some kind of margin.
Hot water use
To heat water for domestic needs, a small heat exchanger-coil is installed in the furnace. Cold water supplied to its inlet is heated when passing through a tube heated in the furnace. Such wood-fired boilers are also called double-circuit boilers: the first circuit is used for water heating, the second for hot water supply.
Here you need to pay attention to this: a wood-burning stove is unlikely to be heated all year round. In summer, hot water is also needed. So either you have to install additional devices for heating water, or heat the stove in the summer.
There is another option - the so-called boiler room. With this method of heating, a reservoir with water is located in the boiler, which is heated by convection. In this case, having melted the stove and heated the water, you have some of its supply.
Review and owner reviews
Boilers "Spark"
Worthy representatives in this type of heating equipment are firewood boilers "Spark". They are manufactured by the machine-building plant in Starobelsk, Luhansk region.
"Spark" has a fairly diverse range of models: with a hob, with a water circuit, turbocharging. There are modifications equipped with a heated towel rail, boilers can be equipped with automation of varying complexity, decorated doors, etc. A variety of models, strict compliance with the requirements of GOSTs, a wide power range - from 10 to 100 kW - allow us to characterize them as the best Ukrainian-made wood-fired boilers.
Wood-burning boiler "Spark" with a stove
The PDGB model works on the principle of gas generation. Any solid fuel, except coal, is used as fuel. The convector type of heating is used: it directly heats the air in the room.
In the Ogonyok KOTV line, the compartment for loading fuel is made wide: firewood up to 50 cm long can be loaded into it. The intensity of combustion is adjusted using the chimney damper, which has 4 positions.
Ogonyok KOTV-30DT is equipped with a turbocharger to achieve higher temperatures and more efficient combustion. In this modification, loading firewood is required every 12-15 hours.
Boilers "Aton"
Another Ukrainian wood-fired boilers. This is the brainchild of the ATON Group corporation. The equipment is produced from cast iron and steel. Cast iron wood-fired boilers "ATON TTK" are water-heating units that can operate in systems with natural or. As fuel, you can use firewood, briquettes, peat. With the predominance of low-quality fuel, the ATON TTK V modification is better suited, in which there is a special fan that supplies air forcibly.
The ATON TRADICJA line is a solid fuel boiler made of steel. They have two modifications - one with a manual draft regulator, the other with automatic control. A feature of this equipment is water-cooled grate. Such an original solution avoids one of the main problems of long-burning boilers - burnout of the grate due to high temperatures in the furnace. Modification ATON TRADICJA C with automatic control is additionally equipped with a controlled fan for forced air supply. This allows you to achieve long-term burning of firewood - a bookmark is required every 12 hours.
Lithuanian Kalvis
Lithuanian boilers "Kalvis" (Kalvis) have very good reviews. This distinguishes them from most other manufacturers: the declared characteristics can be trusted. The company produces both fireplace boilers and units with hob, air and water heating devices. There are household and industrial models.
Calvis has two different options boiler devices. Low-power KALVIS-2-8 and KALVIS-2-12 are simpler. The principle of lower burning is used. KALVIS-2-16 and above have a different firebox.
Perhaps the term “lower combustion” is the result of a not entirely correct translation, since there are still two fireboxes, there is a primary, and there is a secondary air supply, and the burning of firewood is up to 12-16 hours.
For greater efficiency of heating the coolant, the combustion chambers are insulated with heat-resistant material. It also raises the combustion temperature in the furnace. The boilers have a mechanism for shaking off ash from the grate, in some models (2-12 and above) the possibility of laying fuel both from above and from the front is implemented. You can also install a smoke exhauster, an emergency cooling coil (when using coal as the main fuel).
Results
Whatever model you choose, you should still remember that even the best wood-fired boilers, in your opinion, must be installed by specialists. They must comply not only with your requests, but also with fire safety requirements, have a conclusion of the sanitary and epidemiological service on compliance with GOST. Fire safety regulations must be strictly observed. Then you can be sure that your wood-fired boiler (German, Lithuanian, Ukrainian or any other production) will be safe.
IN last years heating costs are on the rise. However, in a country where in most regions, the cold season is 7-8 months a year, you can’t do without it. Homeowners are forced to put up with huge utility bills. But the owners of individual houses have long been looking for an alternative to central heating and standard gas boilers. And of course they find it - a long-burning wood-fired boiler ( wood boilers).
Rice. 1Advantages and disadvantages of heating boilers
Compared to all other types of wood-fired fuel equipment, which are equipped with long-term burning, they have the following heating advantages:
- High level performance and heat dissipation. Boilers can heat large areas and multi-room premises. One can heat a house or cottage up to 200 sq.m.
- General availability of fuel - firewood. Pellets, sawdust, coal and peat briquettes, as well as any combination thereof, can be used as fuel.
- Profitability. With an equal amount of heat output, the fuel costs of a wood-burning boiler are significantly lower than those of a gas boiler.
- Autonomy of work. Wood boilers do not require connection to the power grid, gas pipeline and other communications, which allows them to be used in any premises and buildings.
- Long burning wood burning equipment are highly reliable and durable as they are made of steel or cast iron. Average term equipment service - 15 years.
- The design of the boiler is extremely simple, its maintenance does not require special knowledge and skills, so that many competent craftsmen have the opportunity to make it with their own hands. And a home-made heating device will not be inferior in power and performance to a branded one.
However, like any complex equipment, they have their drawbacks, the main of which is the need for a chimney with good draft and a separate room in the basement or extension of the house. Also, many long-burning models are very sensitive to the quality of the fuel, that is, do-it-yourself firewood put into it must be dry.
Wood boiler design
The design of a heating boiler for long-burning wood is extremely simple and at first glance it does not differ much from a traditional stove.
Its main elements are:
- A firebox that performs the functions of a heat exchanger, which includes a door, a chimney hole, an ash pan (a container for collecting ash), and a blower. It is where the fuel burns. Its size depends on the model and the level of performance (heating). The wall thickness is at least 6 mm steel, or 1 cm cast iron.
- A chimney with good draft that removes carbon monoxide outside the house.
- Water "jacket" designed to cool the combustion chamber. Water is located inside the double walls of the furnace and, when the temperature rises, it is forced out into the heat pipe and, having cooled down, is returned back. "Circulation" is carried out through pipes (upper and lower). In this case, the "shirt" should not be confused with the water circuit.
- Air supply control system and long burning power control.
Depending on the material, wood-fired boilers can be steel or cast iron. The first, at a relatively low cost, require that the temperature in the heat pipeline through which the “shirt” runs does not fall below +60 ° C. This is solved by installing special valves. Cast iron equipment is purchased when it is assumed that they will be used continuously for heating. In particular, they are most often installed with their own hands in industrial premises.
In addition, such equipment can be divided according to the method of supplying firewood - manual or automatic, according to functions - into standard ones for heating and with a water circuit.
Rice. 2The principle and features of the operation of wood-fired boilers
The principle of operation of the boiler on long-burning wood is very simple: dry firewood is loaded into the combustion chamber (by hand or automatically), after which it is ignited in any way. The high heat output of the boiler is due to the fact that the wood loaded into the furnace does not actually burn, but slowly smolders. An order of magnitude more energy is released than with bright, fast combustion. The process of smoldering firewood is slowed down as much as possible due to the air supply through the blower located below.
All ash (mineral waste) from the burnt fuel falls into the ash pan, which requires periodic cleaning. In conventional stoves, when burning, carbon monoxide with soot particles is sent into the chimney. In a long-burning boiler, almost everything burns out and a very small amount of non-toxic smoke escapes to the outside. Thus, the residents of the house are safe and in a heated room. By comparison, one of the biggest dangers of a traditional stove is carbon monoxide poisoning.
Rice. 3The built-in nozzle allows you to adjust the strength and duration of burning, stretching it from 5-6 hours to 3 days (brand Stropuva). If firewood is fed manually, then it is important to remember that before opening the door with your own hands, you must close the blower. Otherwise, the fire splashed out from a sharp influx of air will burn a person’s hands and scorch his face.
Sometimes, to prevent such cases, boiler owners install a so-called curtain in front of the firebox - a home-made additional damper on the screw.
The main difference between the heating of long-burning boilers on wood and heating with a traditional stove is that the long-term burning of fuel starts from above. The supply of air and firewood is also carried out from above.
The peculiarity of this type of heating is also that a large part of its efficiency is related to the quality of the fuel. The drier the wood, the better heating. The best option is acacia and deciduous non-resinous species (birch, aspen, etc.). The worst kind of firewood will be cuttings of fruit trees and uncooked wood.
Boilers with water circuit
In recent years, long-burning wood-burning boilers with a water circuit, which combine the functions of heating equipment and a water boiler, have become increasingly popular with owners of individual houses.
Their main design difference in heating is that inside the equipment with a water circuit there is a tank with water, which, when heated, is forced into the house's plumbing system or into a special container (boiler). Instead, by natural heating or by means of a pump, cold water fills the container, which ... and so on until infinity or the end of the life of the long-burning equipment.
A boiler with a water circuit has the same advantages as other wood-fired heating devices. However, the disadvantages of equipment with a water circuit include higher cost and large dimensions. It should also be remembered that it is impossible to speed up the heating of water, since re-supplying fuel to the boiler with your own hands can only be done when the previous batch of firewood is completely burned out. The same applies to the amount of fuel - anyway, more than + 100 ° C, the water will not heat up.
Rice. 4 Wood burning design diagram boiler with water circuit
Homemade heating boiler: materials and tools
Making a boiler on long-burning wood with your own hands is much easier than it seems. Of course, such heating equipment will not have a warranty and the service life will be significantly less than 15 years. However, such a notion will allow you to avoid significant expenses, since in many households in Russia heating is required not only for a residential building, but also for numerous outbuildings (bathhouse, garage, barn, etc.). Home-made heating is in no way inferior to factory heating in its efficiency.
For heating equipment the simplest design do it yourself you will need the following:
- 200 l metal drum or steel pipe 50-80 cm in diameter, 80-100 cm long, respectively.
- Metal corner and sheets of steel with a thickness of 5 mm.
- A metal circle with a minimum thickness of 50 mm, which will separate the firebox from the ash pan.
- Doors for the furnace bunker and an ashpit.
- Water pipes different diameter.
- Tank made of galvanized or stainless steel.
- Fittings.
Of the tools for working with your own hands, you will need a grinder, a welding machine and protective equipment when working with welding and metal (goggles, mask, gloves, etc.). The cost of a home-made long-burning boiler is approximately 1000 rubles, excluding work.
With the approach of cold weather, many owners country cottages seriously think about the arrangement of autonomous, economical and at the same time efficient heating systems in their homes. The best solution in this case would be to install a long-burning wood-burning heating boiler in the house, which runs on cheap raw materials and is completely independent of external gas and electrical communications. In addition, there is no need to obtain permits in any instances.
A series of solid fuel boilers Roda
Modern heating units from the well-known German company Roda are excellent for heating premises, both residential and industrial, with forced circulation systems. The trade line includes devices with power ranging from 15-95 kW. This makes it easy to select and purchase the right machine for your specific needs. Cast iron is chosen as the material for the manufacture of the case, which significantly increases the operational parameters of the product, including resistance to corrosion phenomena. Boilers use fuel economically and efficiently. With proper use, the device will serve you for decades.
Domestic boilers Zota
The series of units produced by the Siberian plant includes 5 boilers of various capacities. Products are equipped with a cooking surface for cooking. The main difference between the boilers is increased thermal insulation, achieved by using basalt cardboard as a lining. The design incorporates a combined heat exchanger characterized by high heat susceptibility.
In the PechiMax online store, you can purchase a variety of heating boilers at an affordable price, from domestic and foreign manufacturers.
Content
For a long time, a solid fuel boiler belonged to the category of heating equipment, the demand for which was quite limited. This is due to the fact that a conventional non-volatile solid fuel boiler unit, in fact, is a classic stove in a slightly different version - compact and with a water jacket. The main inconvenience remained - the need to add fuel every 3-4 hours and control the combustion process.
Long burning wood burning boiler
To solve this problem, heating units were invented in which solid fuel is fed into the combustion chamber automatically. However, such automation is only suitable for fine-grained fuels, which include pellets, coal chips, woodworking or agricultural waste.
The second way to resolve the issue of how to minimize the number of fuel loads per day led to the creation of long-burning wood-burning boilers. They have different design and the principle of operation, but they are united by a common principle: the laying of fuel should burn as long as possible and give off the maximum amount of heat.
General features of long burning units
Long-burning boilers are capable of operating on organic solid fuels different types, as well as conventional direct combustion units. Thermal energy is transferred, depending on the design, through an air or water convector. On wood fuel, such a heater is able to operate for about 12 hours on average, on coal - 1.5 days.
To obtain such a result in the first place, it is necessary to increase the volume of the combustion chamber in order to increase its capacity. If a direct combustion boiler with a power of 20 kW has a firebox volume of a maximum of 60 liters, then for a long-burning unit this figure will be 100-250 liters, depending on the type and design features.
But an increase in the furnace in itself does not fundamentally solve the issue, since with direct combustion under normal conditions, even a double or triple portion of fuel will burn out very quickly. Therefore, several different engineering solutions were implemented.
Thanks to this, heating boilers on long-burning wood of the following types appeared:
- with an extended firebox;
- with top burning;
- gas generating.
The units differ in design, functionality, cost, fuel requirements. To choose the appropriate option, it is necessary to compare the principle of operation and the main characteristics of heat generators.
Boilers with an extended firebox
Modern wood-fired boilers with an elongated firebox are the simplest version of a “long-playing” unit. Such a heater differs from a classic solid fuel boiler in its horizontally elongated shape, as well as in the fact that air is dosed into the combustion chamber. Due to this, the combustion of the fuel occurs in the optimal mode (“yellow flame”), which guarantees:- economical combustion of firewood, due to which the duration of work on one tab increases;
- maximum heat transfer;
- minimum ash and emissions into the atmosphere.
A solid fuel boiler with an extended firebox on one tab works about 6-8 hours. This is a budget option for heating a country house or a small private house.
Wood burning boiler with an extended firebox Top burning boilers
It is well known that if a burning splinter is turned upside down with the lit part down, it will burn out noticeably faster than the one with the burning end up. Top burning boilers use exactly this principle of the invention.
The upper combustion boiler is a vertically elongated firebox, which is filled with wood, coal or woodworking waste. A special burner is placed on top and moves down as the fuel burns. The air supply in the device is also metered to ensure optimal mode combustion of firewood and maximum heat transfer.
Top burning wood boiler Such long-burning units for heating a house can work for 12 hours on wood and more than a day on coal, they do not require constant monitoring and are suitable for heating private houses.
Gas boilers
Gas-generating boilers of long burning (pyrolysis) are high-tech equipment. This is the most economical and efficient equipment, as it has a high efficiency, reaching up to 97% when using the right fuel.
Pyrolysis wood burning boiler The principle of operation of the unit:
- firewood is laid in a pre-combustion chamber, preheated;
- the fuel is ignited and smolders under conditions of limited oxygen supply, due to which wood gas is released - a mixture of combustible and inert gases;
- combustible gases (carbon monoxide and methane) enter the afterburner through the nozzle;
- in the lower chamber, the gas mixture is burned under conditions of forced air supply, due to which the combustion temperature is about 1000 degrees.
Pyrolysis-type long-burning boilers have the following advantages:
- Efficiency comparable to gas boilers;
- Long work on one bookmark of fuel (up to 12 hours);
- Minimum amount of ash (no need to constantly clean the ash pan);
- Environmental friendliness (carbon monoxide is not emitted into the atmosphere, since it serves as fuel and is burned).
It should be noted that pyrolysis boilers are able to operate on any type of solid fuel, but the efficiency is different. The unit can achieve a maximum efficiency of 97% only when using dry firewood.
Increasing the humidity of the fuel negatively affects the result, since it smolders poorly, emits less combustible gas and leaves a lot of ash. Low quality fuel can reduce the efficiency of the pyrolysis boiler by almost half.
If it is possible to use dry firewood, a pyrolysis boiler will be the most practical solution to the issue of heating a large private house.
Manufacturers tricks
Some manufacturers supply direct combustion boilers to the market, offering to use them as "long-playing" ones due to operation in the smoldering mode, i.e., blocking the normal air supply.
However, doing so is irrational for a number of reasons., despite the fact that the burning time of one bookmark will actually increase:- Heater efficiency is reduced to 50%;
- fuel oxidation is incomplete, which is why the flue gases contain a large amount of carbon monoxide and heavy hydrocarbon radicals (if the draft is poor and such flue gases enter the room even in small quantities, it is dangerous to life and health);
- there is a lot of ash left;
- some types of wood (poplar, willow, etc.) burn very poorly in smoldering mode.
Important! Do not try to operate direct combustion boilers in smoldering mode, this will not bring the desired effect.
Advantages of solid fuel boilers for long burning
Despite all the shortcomings associated with the need to organize a place to store a large amount of fuel and periodically put it into the furnace, "long-playing" solid fuel boilers long burning have some advantages over other types of boilers:- to install such a unit, it is not required to obtain permission from the gas services and other authorities;
- boiler equipment operates autonomously, that is, there is no dependence on centralized networks;
- solid fuel is less flammable, it does not explode and is not capable of instantaneous ignition, unlike liquid and gaseous;
- in many regions, solid fuels are the most affordable.
However, if the house is connected to a gas main, solid fuel boilers are usually used only as a backup heat source.
Principles of organizing heating
A long-burning wood-fired boiler is usually equipped with a heat exchanger for connection to the house's water heating circuit. If the system is designed for forced circulation of the coolant, it is necessary to use an appropriate pump. The boiler is selected in such a way that the operating pressure that its heat exchanger is able to withstand corresponds to the parameters of the heating system. The operating and maximum pressure of the unit is indicated in the product passport.
Important! If there are constant interruptions in the supply of electricity, care should be taken to install a diesel generator or install a non-volatile long-burning boiler unit and mount a gravity heating system. In the latter case, the pipes must have an increased diameter, and a circulation pump is used as an additional option to increase efficiency.
If we are talking O country house with one or two rooms, instead of a water circuit, air convection can be used. The convector oven, which includes Buleryan and similar models, is equipped with tubular elements welded to the walls of the furnace. The air in them heats up and goes up, and cold air enters from below. Such a stove uses wood sparingly and quickly heats up a small room. An air duct system is installed to heat adjacent rooms.
The device of "long-playing" units
When choosing a long-term solid fuel heat generator, special attention should be paid to the materials from which the main components are made. The durability and operational properties of the boiler depend on this. It is also important to pay attention to the choice of fuel, as it has a different calorific value.
heat exchanger
This part is made of cast iron or steel and is a water jacket or tubular structure that surrounds the firebox. The cost of models with a cast-iron heat exchanger is 15-20% higher than analogues with a steel one. The advantage of a cast iron part is durability, as it is made by casting and does not have welds, unlike steel. Cast iron is also less prone to corrosion. At the same time, this material is fragile and does not withstand strong temperature changes - it can burst when the heated metal is cooled sharply.
Boiler with heat exchanger When the coolant boils in the boiler (this is dangerous for the heating system), the steel heat exchanger can be cooled by supplying cold water to it. It is impossible to cool a cast-iron structure in this way, and if it does not work safety valve, may have problems.
A temperature difference that is dangerous for a cast iron heat exchanger can also occur if the circulation pump stops due to a power outage, while the boiler heats up and the coolant in the pipes cools down. When the pump is turned on, the cooled water will abruptly enter the heat exchanger.
Important! You should not purchase a long-burning wood-burning heat generator if the heat exchanger in it acts as a grate - automatics work more often with such a unit, plus, coals stick to the grate and are difficult to remove.
Combustion control
The long-burning wood-fired boiler is equipped with an air inlet with a throttle (rotary damper), thanks to which you can regulate the flame and, accordingly, the power of the equipment.
Pyrolysis boiler device Gas-generating (pyrolysis) boilers are additionally equipped with a system that changes the nozzle flow area, through which combustible gas extracted from firewood is delivered to the chamber.
Power adjustment of solid fuel equipment can be carried out:
- Manually.
- With the use of analog type automation (non-volatile). Typically, the device is made on the basis of a bimetallic plate, the curvature of which varies depending on the degree of heating. The plate is connected by levers with an air throttle. Also, flasks, the filler of which is sensitive to temperature conditions, can serve as temperature sensors that move the damper.
- With the use of an electronic control system. At the signal of the temperature sensor, the controller activates a servo drive that moves the throttle to the desired position. This control option is preferred, but requires power.
Simple models of boilers draw air into the furnace from the room and do not have power adjustment. The efficiency of heat generators with forced supply is higher, but when choosing such a unit, it is recommended to give preference to a model with a fan in the upper compartment of the case - they are more durable. If the air pump is located at the bottom, it draws dust from the floor and fails faster.
Fuel loading and operation
Long-burning heat generators for home heating require proper fuel loading. For efficient operation, it is necessary to fill the firebox in accordance with the manufacturer's recommendations for a particular model.
When starting a gas-generating boiler, you should first let the fuel ignite, and then close the combustion chamber door - when excess oxygen burns out, combustion will be replaced by smoldering and the release of pyrolysis gas for afterburning. For optimal operation of the equipment, firewood with a moisture content of no higher than 20% is required.
The principle of operation of a solid fuel boiler Ignition of a top burning boiler requires the use of a flammable liquid, which is poured over the top layer of fuel. Fuel should be placed approximately 2/3 of the height of the chamber. At the same time, it is impossible to add an additional portion of firewood, sawdust or coal during the combustion process - you need to wait for the complete burnout of the existing bookmark. The solid fuel unit with top combustion must be regularly cleaned of adhering coals.
A heating boiler with an extended firebox is ignited in the usual way and works on all types of solid fuel. It practically does not differ from a direct combustion boiler, except for the service interval increased by 2 times. This is the most budget heater of the presented.
To make the most of home heating thermal energy, which gives a "long-playing" unit, it is required to provide for the installation of a heat accumulator - a thermally insulated container with water, which is heated by excess heat during the operation of the boiler, and when it stops, it ensures the supply of heated coolant to heating circuit. This will significantly save fuel and start the heat generator less often.
Price
Long-burning wood-burning boilers for the home vary greatly in price, which depends on a number of factors, including type, power rating, availability of automation and other features, including the brand of the manufacturer.
When choosing a heating unit for a private house or cottage, suitable for cost and performance, you can focus on the following price order:
- Furnaces with partial gas generation (Bullerjan and the like) - 8-40 tr. for air-convection and 25-50 tr. for models with a water jacket.
- Boiler units with top combustion - 60-120 tr, depending on the power;
- Pyrolysis boilers (gas generating) - 35-500 tr. in accordance with the power and complexity of the design.
Therefore
"Long-playing" models have a significant advantage over direct combustion solid fuel boilers. For heating a private house, it is recommended to purchase a reliable and durable unit.
If a long-burning stove is required for a garage or workshop, it is cheaper to make it yourself or order it from craftsmen.
Long-burning wood-burning boilers are used today for heating private houses and represent improved solutions used earlier. wood stoves. In some cases, they are an excellent alternative to electric and gas heating boilers. However, if you still do not know whether it is worth acquiring such equipment, then you should become more familiar with its distinctive features, pros and cons, which will be discussed below.
In addition, a huge variety of such boilers are on sale, which could save on heating. While others, on the contrary, can cause gaps in the family budget, which is why it is worth taking seriously the choice of a boiler model for heating. For example, some models require fuel every 4 hours, while others do not require replenishment of firewood during the week.
The main advantages of wood boilers
Long-burning wood-fired boilers have many positive features, they can be used for heating buildings that are remote from gas mains. If we consider such equipment more closely, then we can highlight some advantages, among them:
- low cost;
- independence from electricity;
- simple installation scheme;
- environmental friendliness.
Low cost, however, is characteristic only of those boilers that are standard units and are not equipped with any ultra-modern features. These devices are completely independent of electricity. Light may not be connected to the house, while the equipment will properly cope with its tasks. Long-burning wood-burning boilers are also chosen by consumers for the reason that they are easy to install. They are easy to maintain and repair, which allows additional savings in the process of operation.
Why else should you choose a solid fuel boiler
It is also important to pay attention to environmental friendliness, because wood, which is a natural material, is used as fuel. Combustion is not accompanied by the release of external environment toxic compounds that could harm the human body. The danger is only carbon dioxide formed during the combustion of firewood. However, they can be poisoned only if the user ignores the manufacturer's recommendations for observing safety rules.
This indicates that the operation of boiler equipment should be carried out with the utmost care. If you are interested in long-burning wood-fired boilers, then you should pay attention to one more of their advantages, which is expressed in the possibility of using various combustible materials as fuel, such as municipal solid waste.
Main disadvantages
When consumers consider the equipment described in the article, they note that it also has certain disadvantages, which are expressed in:
- impressive mass;
- the need to control work;
- uneven heating of the coolant;
- the need to harvest firewood;
- sufficient fuel consumption.
A number of consumers refuse to purchase such installations for the reason that, made of cast iron and steel, they are characterized by a rather impressive weight. In addition, their work provides for the need for control. The boiler should not be left unattended for a long time. Firewood will need to be added every 4 hours.
Some consumers are also repelled by the uneven heating of the coolant, as well as the impressive fuel consumption, which sometimes does not allow to achieve the desired effect, because wood emits a rather small amount of thermal energy during combustion. Yes, and harvesting firewood is a rather lengthy and laborious process.
For reference
But if the house has a small area, then storage becomes a real problem, because the fuel needs to be stored somewhere, and sometimes a special room should be allocated for this. In order for firewood to be constantly dry, they have to be stored under a special shed or in a house where they take up a lot of space.
Description of pyrolysis boilers
Perhaps you may be interested in a pyrolysis boiler for long burning on wood. This equipment belongs to the family of solid fuel boilers, but has one difference, which is that combustible components are removed from the fuel at the first stage. Combustion is carried out in two stages, first gas is extracted under conditions of high temperature, while conditions are characterized by low oxygen content. At the second stage, the mixture of air and heated gases is burned.
Such a solid fuel boiler for long burning on wood has a metal case, inside of which there are two chambers, one of them is a combustion chamber, while the other is a boot chamber. To protect against high temperatures, the walls of the chambers are lined with fireclay bricks or other material that is heat resistant. It can be made on the basis of concrete.
The main advantages of pyrolysis boilers
If you still do not know whether it is worth becoming the owner of a pyrolysis boiler, then you should consider its main pros and cons, among the first you need to highlight:
- burning duration;
- almost complete combustion of fuel;
- the ability to use large firewood for work.
If we consider these advantages in more detail, it can be noted that the described boilers are able to operate on one batch of fuel for about 12 hours. If you use coal, then under certain conditions this period becomes even longer. A long-burning wood-fired heating boiler is able to completely burn the fuel, which means that the equipment uses most of the energy potential of the wood. This minimizes waste and eliminates the need for frequent cleaning. Yes, and the labor intensity of work when laying fuel will be reduced, because most of the options for the described equipment allow you to limit yourself to laying uncut fuel.
The main disadvantages of pyrolysis boilers
In order to make the right choice, you must also pay attention to the factors that sometimes stop consumers from buying pyrolysis boilers. These installations are much more expensive than traditional solid fuel counterparts. If you familiarize yourself with the assortment of the market, you will be able to understand that sometimes the difference in cost reaches the limit of 50 to 100%. In addition, long-burning wood-fired boilers for the home use forced air injection systems. This suggests that the devices are volatile.
Units consume electricity, interruptions in which can cause big problems. As practice shows, the efficiency of the functioning of such devices largely depends on the condition of the firewood. If they are wet, then the boiler may simply not start. Manufacturers do give recommendations on this parameter. The humidity of firewood should not exceed 25%, which is sometimes very difficult to achieve.
Self-manufacturing of the boiler
If, after familiarizing yourself with all the pros and cons of long-burning boilers, you decide to make one of these models yourself, then you should become more familiar with the technology of work. The equipment can be made of a thick-walled pipe with a diameter of 300 mm, or 4 mm steel sheet. A 6 mm sheet will be the best option. To carry out the work, you will also need a cylindrical container of the desired size.
The simplest design is the one made from a barrel or gas cylinder. In order to ensure directional combustion of firewood, the capacity of a vertical firebox is used. Primary air will be supplied through a vertical pipe to the combustion surface. A telescopic or static structure will need to be installed in the upper wall of the boiler. A rod will pass through the center of the cylindrical furnace. Between the supply pipe and the collar, you need to make a gap, which is formed by welding the side, it will ensure the stroke of the rod and guarantee minimal air leakage into the chamber for burning wood gases.
If you decide to make a long-burning wood-burning boiler with your own hands, it should assume the presence of a damper cover, which will be located at the top of the pipe. With it, you can regulate the air intake. The disc with blades should be reinforced from below. The blades will cut through the air flow in the combustion area. Given the heat capacity, it will be possible to select the material for distribution. The diameter of the disc should be smaller than the size of the firebox.
Homemade boiler dimensions
Homemade long-burning wood-fired boilers should have the following dimensions:
- boiler height ranging from 3 to 5 diameters;
- optimal body size - from 300 to 800 mm;
- wall thickness - 4 to 6 mm.
It is also important to take into account the thickness of the disk, this parameter will be inversely proportional to the diameter. The disk diameter will be 10% less than the chamber cross section. For combustion of pyrolysis gases, a turbulent flow will be used, which is formed by curved blades. If you are interested in long-burning wood-fired boilers for the home, then you can make one of these models yourself.
When carrying out work, it is important to take into account that a pipe will be responsible for the air supply, the diameter of which will be a factor of 0.55 of the cross-sectional area of the chimney outlet pipe. A gap should be left between the collar and the pipe, which should not be more than 2.5 mm. For air intake, a pipe will be used, the height of which rises 150 mm above the collar.
Independent addition of the boiler with a water jacket
A long-burning wood-fired boiler with a water circuit will be even more effective way heating. To connect to the water pipes of the equipment, it is necessary to install shut-off ball valves. A filter must be installed on the pipe through which the chilled water will return. This will protect the heat exchanger from contamination. The same filter is installed on the supply pipe cold water. Shut-off ball valves will be located on both sides of the filters. This will make them easier to clean.
Heating boilers for long-burning wood must be installed together with chemical water mixers, which are located in the piping. This will reduce the rigidity of the coolant and eliminate the formation of scale in the heat exchanger.
Advantages of a pellet boiler
Long-burning boilers on wood (24 hours is not the limit time without adding fuel) is equipment that allows you not to throw resources for a long time. An example is a pellet boiler, which sometimes has a design that allows you to load fuel every few weeks.
The devices assume the presence of a container in the side part, where the pellets are placed. The volume of this tank allows for long-term operation of the boiler without human intervention. The volume of the compartment may be different. With the help of a special mechanism, fuel is supplied from the bunker to the boiler, which also uses electrical energy during operation.
Pellet boilers are chosen by consumers most often because of their high efficiency, which reaches 95%. In addition, this equipment provides almost complete combustion of fuel, as is the case with the boilers that were described above. This indicates that cleaning can be done once a month.
Cons of pellet boilers
Pellet boilers sometimes lose to other types of heating equipment, because they are expensive and also depend on electric current. In operation, this equipment uses exclusively low-ash and whole pellets, which are sometimes quite difficult to find on sale.
Conclusion
Solid fuel boilers are an excellent way to provide a home with autonomous heating. With the help of such installations, you can save a lot on energy resources. Some craftsmen are so sure that solid fuel boilers are the best among other types of heating equipment that they even try to make such equipment on their own, because if you buy it in a store, it can be quite expensive.
