Boilers and stoves of long burning on sawdust and other wood waste. How to make a pyrolysis boiler on sawdust with your own hands Sawdust boiler
A versatile, economical and easy-to-maintain sawdust boiler with your own hands will completely solve the problems with heating a country house or a small country house. The use of wood chips as fuel reduces the homeowner's heating costs, while such installations differ in functionality and are able to work from one gas station for several days.
The principle of operation of the boiler
To date, there are various designs of heating boilers operating on sawdust. These can be classic potbelly stoves with a thermal circuit connected to them. Modifications in which there is no ash pan are very popular, and fuel is loaded from above using a bunker and a mechanized auger, which makes it possible to automate the operation of heating equipment.
Modifications of boilers with a bunker are not only efficient, but also make it possible to significantly simplify the heating of a private house. The homeowner does not have to reload fuel daily, and provided that high-quality dried sawdust is used, such heaters will be as efficient and economical as possible. Separate modifications, which are equipped with larger furnace tanks and additional bunkers with sawdust, can operate on one load of fuel for 5-6 days, providing heat to a private house with an area of 150-200 square meters.
pyrolysis boiler simply, do it yourself
The features of the operation of heating devices of this type include the following:
- Possibility of adjusting the air supply to the burner.
- Large fuel tank.
- Increased water jacket and heat exchanger area.
- Combustion of fuel, depending on the modification of the boiler, goes from top to bottom or from bottom to top.
Autonomous heating boilers on sawdust, which use the pyrolysis principle of operation, are popular. Such installations have several combustion chambers at once, allowing you to significantly increase the efficiency of the equipment. In the lower furnace, the fuel smolders, under the influence of high temperatures, gas is released from the wood, which is burned in the upper compartments, which ensures the highest possible efficiency of the equipment.
Such long-burning boilers on sawdust have a design similar to solid fuel pyrolysis plants. The only difference is the presence of an additional bunker and a special screw system that automatically supplies fuel to the combustion chamber.
Hardware Benefits
In many ways, the popularity of heating appliances that run on wood chips is due to the many advantages of this technology. DIY a long-burning sawdust boiler has the following advantages:
- Safety of use.
- Ability to control the consumption of raw materials and temperature.
- Environmental friendliness of the equipment.
- Minimum fuel costs.
- Rapid heating of the room.
- High efficiency.
Do-it-yourself sawdust boilers are characterized by versatility and efficiency. With the help of such heating equipment, it is easy to heat a room of any size. Thanks to the simple design of the device, you can make it yourself, and later you can take fuel for free at sawmills or buy ready-made dried pressed sawdust briquettes.
Of the minuses of sawdust boilers, their increased requirements for fuel quality and its moisture indicators are noted. You will also need to periodically clean the chimney from ash and soot. The efficiency of the equipment and its safety of operation will directly depend on the correctness of such service.
Solid fuel pyrolysis boiler for: wood, sawdust, shavings, wood chips, biomass, pellets, briquettes
Operating modes and protective systems used
Factory models of boilers operating on wood chips and sawdust are equipped with various security systems that prevent equipment from igniting and overheating. Some models also have additional sensors that detect high levels of carbon monoxide and are able to detect smoke, thereby warning of a fire hazard.
The equipment can operate in several modes at once:
- Maximum performance.
- Average power.
- Pause mode.
The maximum operating mode of the boiler is activated immediately after the equipment is turned on and if there is the required amount of fuel in the bunker. As soon as the coolant and the air in the room warm up to the desired level, the automation will independently reduce the intensity of combustion, which will ensure the efficient use of fuel.
The medium power mode allows the equipment to work as long as possible from one load of fuel. The intensity of sawdust burning in the furnace is regulated by increasing or decreasing the air flow into the combustion chamber. When this mode is activated, the boiler, equipped with additional automation, can maintain the temperature in the room at a given level.
In the "Pause" mode, the boiler does not heat the room, and the combustion of the fuel stops or its intensity is reduced to a minimum. Subsequently, the homeowner can quickly heat the boiler by switching it to medium or maximum operation.
The presence of operating modes of the boiler allows you to guarantee the convenience of using the heater, increasing the safety of its operation. With an automatic control system, the homeowner can set the desired temperature of the coolant at will, and the built-in sensors will reduce or increase the intensity of heating, ensuring the comfort of living in a private house.
Long-burning mine boiler 25 kW on sawdust EVERYTHING from IGNITION to FADE-OUT. Video 1 / 2
Basic fuel requirements
The efficiency of a solid fuel boiler will largely depend on the quality of the fuel. It is recommended to use well-dried small chips of various types of wood. The sawdust has the following requirements:
Separate modifications of boilers, in which the function of automatic loading of fuel from the bunker is implemented, cannot work with sawdust with a moisture content of more than 40%. Therefore, the quality of drying chips must be given due attention. For the convenience of loading and storing such fuel, pressed sawdust is often used, which are offered at affordable prices, which significantly reduces the cost of heating a private house.
DIY manufacturing
On sale today you can find various modifications of autonomous heating boilers operating on wood chips and sawdust. Despite all their advantages, they have one significant drawback - the high cost of equipment. Therefore, many summer residents and owners of private houses make boilers that are universal in use on their own, since the simple design of such equipment allows you to design it even in the absence of relevant knowledge and work experience.
To make a boiler on wood chips with your own hands, you will need the following tools and materials:
On the net you can find various drawings for the execution of boilers operating on sawdust and wood chips. The easiest way to make such heaters is on the basis of a pipe or a gas cylinder. You just need to use strong thick-walled steel, which will ensure the durability of a self-made boiler.
This completes the work on the manufacture of the heating boiler. It is necessary to conduct a test run, check the quality of welding, and also make sure that there are no leaks in the water jacket, along the contour of which the coolant circulates. Subsequently, it is possible to upgrade the heating boiler, to which a sawdust hopper and a screw mechanism for automatic loading of chips into the combustion chamber are additionally mounted.
Sawdust boiler
By completing a home-made pyrolysis boiler on sawdust and wood chips, you can not only solve the problems with heating a small private house or country house, but also reduce the cost of living outside the city in the winter season. In specialized stores, you can purchase ready-made industrially manufactured boilers with one or two circuits, which are completely safe in operation and equipped with control automation.
If necessary, it is possible to manufacture universal versions of autonomous heaters, which will differ in their power indicators, the duration of operation from one refueling, as well as a number of other characteristics.
With rising energy prices, more and more people are setting themselves the goal of getting as much energy as possible from sources that were previously considered junk. At the same time, used oil, household waste, old car tires are considered as fuel.
Today we will talk about how to arrange a sawdust stove inexpensively and with our own hands, and this will be a unit that works on the principle of long burning.
After all, it will not be a secret for anyone that in our country there are regions where wood chips and sawdust can be used for heating almost for nothing, except for the cost of their delivery.
There are long burning stoves with connected water and air circuits. Thanks to this, the sawdust stove allows you to heat a fairly large area.
In the article on heating stoves for greenhouses, we have already considered a do-it-yourself version of a sawdust stove, but this version of the stove is able to heat a relatively small area, and this is due not to the lack of a water or air circuit, but to a small area using hot gases.
The figure shows the drawings of this furnace.
Sawdust stove from a 200 liter barrel
As can be seen, at full load, the thermal area of the furnace is about 1/3 of the total area. In the figure, this area is highlighted with red shading.
With this arrangement, there is a loss of thermal energy leaving through the chimney. Of course, you can try to get as much heat as possible by increasing the length of the chimney through the heated room. But this is not entirely rational, and in some cases it is simply impossible due to the design features of the room and its area.
This stove on long-burning sawdust is good for its simplicity, because by and large it can be made within a few hours from improvised materials.
Problem solving - loop device
But today we are interested in a long-burning sawdust stove, which can be used to heat rooms as large as possible.
Of course, it will be necessary to install a water or air circuit, but first let's solve the question: is it possible to increase the thermal area in a furnace of this type without increasing the length of the chimney?
The first shows a long-burning furnace with an external smoke circuit. The device completely repeats the previously presented sawdust stove. The only change is in the circuit through which the hot flue gases pass and the bottom position of the chimney.
The first shows a furnace with an external smoke circuit. The device completely repeats the previously presented oven. The only change is in the circuit through which the hot flue gases pass and the bottom position of the chimney.
As you can see, the changes made it possible to significantly increase the thermal area of the long-burning furnace without increasing the length of the chimney. The volume of the furnace remained unchanged.
As you can see, the changes made it possible to significantly increase the thermal area of the furnace without increasing the length of the chimney. The volume of the furnace remained unchanged.
In the second case, the internal circuit is arranged inside the existing furnace. The thermal area also increased. The only drawback of this installation is the reduction in the loading volume of sawdust.
But there is an advantage: it will not be difficult to arrange such a circuit, the only thing that is required is installation inside a 200-liter barrel smaller diameter and rearrangement of the chimney.
As you can see, a slight refinement will significantly increase the efficiency of using such a seemingly simple furnace.
New system on old principles
But that's not all. A homemade sawdust stove allows you to create even more efficient designs.
The picture shows a long-burning boiler with the ability to connect to a water heating system. Remarkably, the boiler can be made by hand, it works on sawdust, small chips and various household waste. But of course, first of all it is designed to work on sawdust.
Upon closer examination, our readers will notice some similarities between this boiler and. But it is not so.
The pipe passing through the cover, although it is a blower, does not have the shape of a piston and is completely motionless during operation of the boiler. This picture shows a fully charged boiler. As you can see, the pipe is recessed almost completely inside; at the "Bubafoni" it would protrude significantly from the boiler.
Materials for the device
Let's look at how to make such an oven on sawdust with your own hands.
For its manufacture, without register, you will need:
- Pipe diameter 400 mm, wall thickness 10 mm. You can, of course, use a thinner wall, but then the life of the boiler will be significantly reduced.
- Blower pipe diameter 76 mm. When burned, it can always be replaced, so the wall thickness does not matter much.
- Metal for cover thickness not less than 10 mm. In this case, the cover must be reinforced at the edges. Otherwise, it will lead from high temperature.
- Chimney pipe diameter 100 mm.
Internal stuffing
How is this boiler arranged?
The figure shows that the boiler consists of three parts:
- Boiler with register and chimney.
- Boiler covers.
- Pipes blew.
In this position, the boiler is before loading the fuel.
We build a boiler on sawdust
How to make such a boiler yourself?
A plug is welded to a pipe with a diameter of 400 mm on one side. This will be the bottom of the boiler. The height of the boiler depends on your needs. Calculate in such a way that during normal operation one bag of sawdust is enough for 8-10 hours.
Our advice: a 1500 mm high boiler with a full charge can work up to 40 hours without recharging.
- A cover is cut out of metal 10 mm thick.
- The picture above shows that it is made in the form of a polygon, this is not important, it's just that it's much easier to cut thick metal if you use a guillotine.
- Exactly in the middle of the cover, it is necessary to cut a hole of such a diameter that a pipe with a diameter of 76 mm can be freely inserted into it. The gap should not be too large.
Our advice! It is quite difficult to cut a completely even hole in thick metal at home. Therefore, on a lathe, make a thick washer. It should be freely put on the 76th pipe and at the same time cover the irregularities in the opening of the cover. By electrowelding the washer to the lid, you will get a perfectly even hole into which the 76th pipe fits perfectly.
- On the side, in the upper part of the boiler body, it is necessary to weld a chimney outlet from a 100 mm pipe.
Making a blower
Basically, the boiler is ready. It remains to make a blower.
The figure shows how it is arranged.
- A piece with a length equal to the height of the boiler is cut from a pipe with a diameter of 76 mm.
- In the lower part, 3 or 4 pieces of reinforcement or a steel bar are welded in such a way that the blower increases in length by 100-150 mm. This is just the distance that it rises above the lid.
- Using a grinder, holes 100 mm long and 5-7 mm thick are cut in the blower. The quantity directly depends on the diameter of the body pipe and its height. They are located on 1/3 of the blower.
How to load fuel correctly?
The picture shows an empty firebox. How does the stove work and how to use it?
Unlike, for example, "bubafoni", the blower pipe is inserted immediately into the firebox with the pins down. They should rest against the bottom, while the blower is located in the center.
Fuel Loaded - Start
- You can ignite the fuel.
- You can set it on fire without the lid installed, but it’s better to install the lid right away, and splash some mining with kerosene or gasoline into the blower, 50 g is enough.
Our advice: to adjust the draft on the blower, you can install a damper in the chimney.
- After the fuel ignites, it is necessary to cover the damper by ¾ of the hole.
- After 2-3 minutes, the damper should be slightly opened and adjust the desired air supply.
- When the oven comes into operation, you can hear a steady buzz. With the help of the damper, the operating mode of the furnace is regulated.
We install the register for the coolant
Now you can think about connecting the boiler to the heating system. To do this, you will need to install a register at the outlet of the chimney boiler.
The figure clearly shows the installed register with the connected supply and return connected to the central heating system. This is one option, you can use a completely different one. The main thing is that it should correspond to the thermal parameters of the boiler you made and fully satisfy the volume of the installed radiator heating system.
We will not dwell on the structure of the register in detail. Let's say one thing: the closer to the boiler it is installed, the more efficiently it works.
Pipelines connected to the register
Basic rules of thermal insulation
But that is not all. You can significantly increase the efficiency of the boiler if you perform its thermal insulation.
We have talked many times on our pages about the thermal conductivity of materials. The article has a video where it is accessible to talk about such an effect as thermal radiation.
Let us briefly note that during the operation of any furnace, thermal radiation is generated that freely passes through the metal. If our boiler worked without a register, it would be great, it would easily heat the room in which it is installed.
- But after all, our boiler is mainly aimed at heating the coolant passing through the register installed on the chimney.
- This means that we absolutely do not need heat losses leaving through its walls, they must be directed into the chimney.
Lossless thermal radiation
In the above article and in the video, this issue is discussed in detail. It becomes clear that lining the boiler with bricks close to its walls will create an excess of thermal radiation in the boiler furnace, which, together with the exhausted, hot gases, will rush into the chimney. What we need, and the damper installed in the chimney after the register, will allow you to well regulate the operation of the boiler and the heating of the coolant.
You can overlay the boiler and the register with basalt wool, and make a casing of tin on top.
Boiler device on a permanent basis
If there are no problems with sawdust in your region, and this heating method is the most profitable, you can install this boiler more rationally and conveniently.
The figure shows the installation diagram of the boiler:
- For its device, a pit of the appropriate size was dug.
- A foundation is laid at the bottom of the pit.
- The walls of the pit must be strengthened from sprinkling.
- The boiler is installed in the pit.
- Around the boiler, inside the pit, thermal insulation is arranged.
- The lid of the boiler is thermally insulated separately so that it can be removed.
- Heat carrier pipelines are connected.
- The register is also insulated.
- The chimney is connected.
- The boiler is ready to work.
Service? No problem!
As can be seen from the figure, excellent thermal insulation of the boiler is achieved and maintenance is greatly facilitated. With a sufficiently high boiler, loading fuel is not entirely convenient, but in this embodiment it is not difficult.
- It is enough to open the lid, which is almost at floor level, and you can load fuel.
Many may have a question: how to clean the boiler? We can assure you that there will be no problems.
- During the operation of the boiler, the fuel burns completely.
- At the end, there is a small handful of ash that fits into one scoop.
- It seems that for a person who makes sawdust stoves himself, it will not be difficult to make a brush and a long-handled dustpan.
Can the boiler be installed outside?
What else is worth noting, you can install the boiler in this way generally outside the heated room. You just need to install a box on top and insulate the pipelines well. In this embodiment, the boiler will not cause any trouble at all and will not take up extra space in the room.
Having considered the issue of constructing a boiler on sawdust, assembled by oneself, it becomes clear that with certain skills and knowledge, a quite decent heating boiler can be obtained from a simple unit.
Electronics to the rescue
We submitted an idea and considered one of the options. But if you want, you can still improve this unit:
- Install the electric boiler draft control damper.
- Install temperature sensor.
- Install smart thermostat.
By connecting all this into one circuit, you can get a boiler that can successfully maintain a given temperature.
Knowledge and skills are the key to safety and success
The installation of a highly efficient register can further increase the efficiency and will completely allow even a small house to be heated with this system.
In conclusion, a few words about security. Assembling the boiler with your own hands, do all the work efficiently and accurately. This is especially true for welding and working with a grinder.
If you do not have sufficient experience in working with these types of tools, it is better to invite a friend or hire a specialist who can perform these types of work.
Remember that any stove and boiler are fire-hazardous units, the consequences of which can be catastrophic if used incorrectly.
Good luck and warmth to your home!
A heating boiler on sawdust is economical, it is easy to do it yourself.
Boiler pros and cons
The benefits include saving money and fuel. There are always in the house shavings, wood, waste sawdust, wood chips or even garbage that is prone to burning. All this can be used for heating. You can make it with your own hands from improvised means: gas cylinders, sheet steel more than 4 mm thick, pipes of different diameters. Device for sawdust or wood chips quickly warms up a room of 70 square meters. meters. If you need more heat transfer, you can make a second boiler.
- Unaesthetic appearance of the unit.
- Its insecurity when the walls are heated (80-100 degrees).
- Fire hazard.
You need to install a heating boiler in a place where there are no flammable objects. You can isolate the device from neighboring objects with technical wool or other non-combustible materials.
The unit on sawdust can be lined with thin sheet metal with a polymer coating. Two problems will be solved immediately - the ignition of nearby objects and the unsightly appearance of the pyrolysis boiler.
Manufacturing
The most suitable unit for a long-burning pyrolysis boiler is the former. A bottle of imported gas will do.
- Cut off the top of the balloon.
- We weld a strip of metal at the top from the inside and outside (for hermetic closing with a lid).
- We make a lid from the top of the cylinder, grinding off all the roughness so that it fits snugly against the main part of the boiler.
- We weld a pipe with a diameter of 5-8 cm to a metal disk. The disc must be made of non-combustible metal, durable, refractory steel or cast iron. The diameter of the disc should be slightly smaller than the inner diameter of the balloon in order to fit snugly into it.
- The height of the welded pipe must be 20-30 cm more than the balloon height.
- In the former gas cylinder, it is necessary to make a side upper hole for smoke to escape during combustion. This pipe can then be extended and exposed outside of the room.
- Cooking a water jacket around the cylinder. Or we find a metal vessel, which is 10 cm larger in volume than our device in radius. It should be at the level of the cylinder cap in length.
Read also: Choosing a solid fuel boiler for long burning
Leak test
Before use, check the boiler for sawdust or wood chips. Most a common type of check is hydraulic, when all vessels are filled with water and see if there are any leaks. In such places, another welding is done, which eliminates all leaks and holes.
Furnace process
- We fill the boiler with fuel: sawdust, you can vertically put several logs of firewood, wood chips and others. Thanks to the pyrolysis combustion of dry fuel, the unit will be heated.
- We put the pipe with the lower disk. The disk is a kind of fuel press. With prolonged burning of wood fuel, the disk will lower and the pipe will, as it were, fall into the boiler. The pipe is needed to supply air, without which any combustion is impossible. There must be a cap on the pipe (it can be arbitrary) in order to either increase or decrease the rate of long-term burning of the fuel.
- The former gas cylinder is already in a water frame. With prolonged burning of wood waste or pyrolysis burning of wood chips, heat will be released, which will heat up the walls of the inner cylinder, this will warm the water, which will give up its heat to the environment through the steel frame.
- Can weld a pipe outlet to the outer cone, which is connected to the radiator by means of welding or through a thread. Then the heating area of the house can double.
Solid fuel boilers have long been seriously competing with traditional gas equipment. The efficiency of solid fuel appliances, as well as their efficiency, has recently grown especially rapidly. This is facilitated not only by the use of modern technologies, but also by the use of fuel, which was not even paid attention to before.
Boilers on sawdust began to enjoy particular popularity, although they are rare in our country. Therefore, few people even have an idea about the principle of their functioning. Nevertheless, such boilers are really worthy of yours, because they have a lot of advantages - among them are environmental friendliness and the ability to save money. And if we add to this the fact that the cost of traditional fuels is growing every day, it turns out that soon these devices will become simply irreplaceable. With the help of a sawdust boiler, you can heat greenhouses and workshops, as well as private houses, moreover, completely.
introductory video
How does a boiler of this kind work?
The main part of any heating device that runs on sawdust is the combustion chamber. It is there that the heat exchanger is located, which heats up when the sawdust is burned. During combustion, the fuel is located on a special grate, due to which all residual waste enters the ash pan - a special container that should be cleaned periodically. On average, the ash pan is cleaned about once every three months, but, of course, this period is relative, since much depends on the intensity of heating.
Sawdust is, in fact, waste from the woodworking industry, and, as you know, they cannot give a strong flame. For this reason, heated gases pass through the heat exchanger, additionally heating its surface. To heighten the effect, the heat exchangers are made mainly of a spiral shape, but there may also be several tubes that are interconnected. The material from which the heat exchangers are made must be resistant to rust, as well as to high temperatures; moreover, it must be an excellent conductor of heat. The heated gases, having transferred thermal energy to the exchanger, go into the chimney, being completely cooled.
In order to obtain a high efficiency factor, sawdust boilers use not only the thermal energy that was formed during the combustion of wood, but also the by-product of this process - pyrolysis gas. But you must adhere to specific conditions in order to receive this gas. So, the amount of oxygen in the combustion chamber should be minimized, which is why the device is equipped with an artificial ventilation system - it will not only remove air from the furnace, but also catch up with it if necessary. In order for the pyrolysis gas to also burn, the furnace must be divided into several separate parts:
- In one of them, the sawdust itself will burn.
- In the other - the gas displaced from the first chamber by means of a special burner.
Boilers operating on sawdust, as well as other heating equipment, can be of two types.
- Single-circuit, capable of exclusively heating.
- Double-circuit, which both heat the room and supply hot water.
How fuel is supplied
In general, such boilers can operate on any wood fuel, from biological briquettes to ordinary firewood.
Note! In order to operate fully automatically, sawdust boilers must only use shavings and sawdust!
In order for the device to be able to “eat” firewood, its combustion chamber should be redone. But in most modern models, everything that is required for conversion is already included in the kit.
Regardless of what type of fuel is used, pyrolysis boilers need to be dry. If it is wet, then steam will form during combustion. And if the steam mixes with the gas, then the latter will become heavier from this, and the combustion process itself will deteriorate significantly. Therefore, it is not strange that each solid fuel device spends up to 1/3 of its power precisely on drying the fuel.
You should pay due attention to the fuel supply, which consists of two elements:
Note! Automatic boilers are characterized by the fact that they supply fuel continuously! This will allow you to make a bunker for him, located underground.
An underground bunker is good because it not only stores fuel, but it saves free space in the house. Often it is installed in such a way that its highest point is located at the same level as the foundation itself. In the same place, a hatch should be located through which the fuel will be poured immediately from the transport that delivered it. Also note that the bunker should be placed in the room adjacent to the one where the boiler is located in order to easily establish a fuel conveyor.
Pros and cons of this material as a fuel
First, consider the advantages of this material as a fuel, because there are much more of them than disadvantages.
- Any wood fuel is an environmentally friendly product that, even when burned, will not harm the environment.
- Such fuel is inexpensive, because it is, in essence, ordinary waste.
- Today sawdust boilers are fully automated, thanks to which all work processes are controlled.
- Sawdust emits more heat than, for example, firewood, and can burn twice as long.
- Sawdust can be used at any time, as it is always dry and catches fire very easily.
- During operation, practically no soot is emitted.
- The maintenance costs of such a boiler are significantly lower than for its counterparts.
- Today, even special pressed sawdust is sold, sealed in a convenient package.
- The fuel is compact, which makes it very convenient to store it.
- Finally, sawdust does not emit any toxins when burned.
And now about the shortcomings, which, as we promised, are not so many.
- Sawdust is loose, which is why it is not very convenient to transport them.
- The combustion parameters of this type of fuel are relatively low.
Features of the choice of boilers operating on sawdust
In order to choose the right boiler that uses sawdust as fuel, special attention must be paid to a number of aspects. First of all, objectively evaluate the size of the house to be heated. Based on the data received, you will be able to determine what power device you need. To correctly calculate this power, use a simple well-known formula.
For 10 square meters of space, 1 kilowatt of device power is required
It is important that when making these calculations you take into account the following parameters of your home.
- Thermal insulation.
- Number of windows and doors.
- Ceiling height.
In addition, pay attention to whether the model you like is capable of automatically supplying fuel to the furnace. If this procedure is automated, then the further operation of the boiler will be easy and relaxed. As a result, you will spend less time on controlling all the working processes of the device.
Finally, most modern sawdust boilers can be operated in combination with additional devices. It can be, for example, a household drying chamber. That is why when buying a boiler, pay special attention to the additional options available in it.
As a conclusion
So we found out that sawdust boilers are ideal for a country house. Judge for yourself: fuel for it is cheap, because it is ordinary waste from the woodworking industry, no substances harmful to health are released during the combustion of fuel, and the operation of such boilers is a fairly simple procedure. In general, if you have chosen sawdust as fuel, then you have made the right choice!
sawdust - lovely material for heating houses and greenhouses.
They consist of wood, which means that when used correctly, they are only slightly inferior in terms of heat capacity to firewood.
You can get them cheap, and in some cases even for free.
- houses;
- makeshift;
- greenhouses.
We will also consider in detail all types of heating stoves and long-burning boilers that can use sawdust as fuel.
Before talking about the features of boiler houses on sawdust, you need to deal with yourself combustion mechanism this fuel, because it is very different from the mechanism of burning wood.
No matter how tightly the firewood is stacked, between them there is always air passes, and in sufficient quantity to support combustion.
Even loosely laid sawdust skips much less air, so the smoldering quickly dies out without supplying additional air to the combustion zone.
Sawdust burners work effectively only when fire moves from top to bottom. Therefore, only a layer of sawdust 2–5 cm thick is constantly burning.
Due to the fact that only a small amount of fuel is involved in combustion, power boilers on sawdust and stoves working on them, with the same with wood and coal heating appliances 2-3 times less.
Another factor that reduces the power of the boiler or furnace is the low combustion temperature of sawdust.
If firewood burns with the right air supply, then the flame temperature exceeds 1000 degrees, often reaching 2000 degrees in tongues of fire. And this powerful fire, because the whole mass of firewood emits pyrolysis gases.
The temperature of the fire near burning sawdust, even with the right air supply, does not always reach and 1000 degrees because of low flow of pyrolysis gases.
Pyrolysis gases effectively exit only from the upper layer with a thickness 5–15 mm.
From sawdust that is burning or heated, but located below, the gas escapes with difficulty, because the sawdust located on top interferes with it.
Despite these shortcomings, sawdust perfect fit for boilers and long-burning furnaces.
After all, well-compacted sawdust burns a very long time.
Often, a home-made iron stove burns for 5–8 days from one filing of sawdust, providing heating for the entire house.
Suitable heating systems
For heating with sawdust of private houses and any buildings use such systems:
- heating stoves;
- heating furnaces with a water heating register or heater;
- water heating with radiators;
- water heated floor;
- air heating;
- air heated floor.
Heating stoves heat space around you and therefore only suitable for small houses. At a distance of 10 meters from the stove, the temperature drops by 10-15 degrees, so in large houses the stove can only act as an additional heater.
Heating furnaces with water heating register or heater combine the advantages of furnaces and boilers. They give the same heat as a conventional heating stove and heat the coolant, which enters remote rooms through pipes or air ducts.
The large mass of the furnace turns it into heat accumulator, thanks to which you do not have to re-heat the boiler every 2 hours or throw firewood into it every hour. The oven will maintain temperature coolant up to 6–10 hours, so you can heat 2-3 times a day.
Water heating with radiators in each room can be used with both a water boiler and a sawdust stove if it is built into it. water register. Like any other water heating, it can work on natural or forced circulation of the coolant.
In systems with natural circulation hot water first rises to the ceiling, then descends into each room and enters either radiators or underfloor heating. In systems with forced circulation water is driven by a pump, so all pipes can be laid under the floor.
Water and air underfloor heating not only heats the room, but also improves its microclimate. In winter, it is very pleasant to walk barefoot on the floor, feeling its warmth with your feet. Main lack of underfloor heating- the high cost of materials and work, because it is necessary not only to lay air ducts or a water pipe, but also to qualitatively insulate the space between the floor and the ground or foundation.
Air heating also costs expensive, as well as a warm floor, because it is necessary to lay air ducts throughout the house, as well as put automatic humidifiers due to the strong drying of the air. A furnace with a heater can be used as a heat source.
The difference between furnaces and boilers is only in the presence of a boiler water jacket, that is, the space between the hot body and the outer casing is filled with water.
Here distinctive features each heater:
- bake– direct heating of air and surrounding space;
- heater– air heating for delivery to other rooms without heating the surrounding space;
- furnace-heater- heating of the surrounding space and heating of air for delivery to other rooms;
- oven with register– heating of the surrounding space and water for delivery to other rooms;
- boiler– heating water for delivery to other rooms.
Therefore, heaters and boilers are installed in utility rooms and often insulated from the outside. After all, it makes no sense to spend thermal energy on strong heating of the utility room, and the less heat is spent on this, the more other rooms will get.
Requirements for heating appliances
For heating with sawdust, it is necessary to use long-burning boilers and stoves that comply with the following conditions:
- fuel burning top down;
- big outer surface area(important for ovens);
- big heat exchanger area or water jacket;
- big firebox volume;
- opportunity air supply into the combustion zone.
Due to the small size of the sawdust, it can be fed into the furnace or boiler automatically, which is even more increases battery life heating device. Most often, auger feed is used for this - a rotating auger raises or lowers sawdust from the bunker and scatters them in the combustion zone.
When there is too much ash, the heater is stopped and cooled to clear of ashes and reload with fuel.
For heating with sawdust, boilers and long-burning stoves of the Stropuva type (the Russian analogue of Bubafonya) are well suited. These devices have firewood burning principle, and air enters directly into the combustion zone.
Furnaces and long-burning boilers that run on sawdust can not only be bought, but also made by hand. In home-made devices, the requirements for heaters described above are also implemented.
Furnaces and boilers for sawdust
There are 2 types of fireboxes, which differ in air supply method:
- above, through the descending air duct;
- from below, through a pre-made channel in sawdust.
The most famous furnaces and boilers of the first type are devices under the Stropuva brand. They are produced both in the form of furnaces and boilers.
As we said in the article (Fuel from sawdust), the difference between stoves and boilers is that the first heat the air directly, and the second heat the coolant. Then the coolant, which can be either water or air, enters the rooms through pipes and heats them.
With drop down duct
Furnaces and long-burning boilers Stropuva arranged like this:
- body is made of pipes with a diameter of 50–70 cm;
- cut into this body two doors- loading from above and cleaning from below;
- passes through the lid telescopic tube(in home-made devices it is replaced by an ordinary pipe of great length) - an air duct;
- welded to the bottom of the duct steel circle thickness 10 and a width slightly less than the inner diameter of the body;
- attached to the top of the disc. chain or steel cable for lifting the air duct;
- welded to the underside of the disk corners or channels, creating an optimal gap between the disk and the fuel;
- smoke outlet made a little higher than the cleaning door.
Such boilers and furnaces work on sawdust as follows:
- lifting the air duct with a cable or chain, the furnace or boiler is loaded with sawdust, tamping as much as possible their;
- loading sawdust, from above lay the kindling- paper and various chips;
- waiting for the kindling to flare up, lower the duct and close the loading door;
- air supply is set to maximum, due to which the top layer of sawdust flares up and the furnace / boiler goes into operating mode;
- fire and smoke rise through the space between the disc and the body and heat both the air duct and the housing;
- oven starts radiate heat, and the boiler heats up the water jacket;
- as the sawdust burns out, their level becomes lower and the air duct descends after it, such a system provides a constant flow of air into the combustion zone and optimal fuel combustion mode.
With bottom air inlet
Boilers and furnaces without a descending duct are designed and operate somewhat differently. They have the air duct goes to the furnace from below.
Such heating devices are loaded through flip cover. The chimney is connected just below the hinged cover.
flip cover seal asbestos cord or tape.
During loading, a long wooden cone-shaped plug is inserted into the air duct (the upper diameter is 1.5–3 times larger than the lower one).
The sawdust is compacted tightly and after the loading is completed, the plug is pulled out - air enters through the resulting channel to the upper burning layer of sawdust.
Kindling is placed on sawdust and set on fire. When the kindling has flared up, close the hinged lid by setting the chimney damper and the air supply regulator to the maximum draft mode.
After the sawdust flared up, reduce air supply and the stove or boiler goes into long burning (smoldering) mode.
Furnaces, boilers and heaters: which is better
When choosing heating that runs on sawdust, the following must be considered:
- volume of water in the water jacket the boiler should be 10–15% of the total volume of water with the heating system, therefore it is advisable to use forced movement of water through thin tubes;
- water boiler cost"Stropuva" starts from 65 thousand rubles, and the price of do-it-yourself sawdust boilers - 30-50 thousand rubles, including the cost of the material;
- air heating not only heats, but also dries the air;
- water heating pipes can be hidden under the trim, and air heating pipes will have to lay in plain sight due to the large cross section (pipe diameter in cm is equal to half the area of the room in m²);
- find industrial heaters that work on sawdust (boilers and stoves that heat air, which is then delivered through pipes to rooms) of long burning very difficult, and their cost often exceeds the price of the Stropuva boiler;
- the cost of manufacturing heaters is comparable to the price of manufacturing a boiler;
- the costs of material and laying of water and air heating are approximately the same and amount to 15-20 thousand rubles for one room measuring 15–20 m 2;
- furnace manufacturing costs are 20-50 thousand rubles depending on the size.
Heaters and boilers are well suited for heating big houses, because they heat the coolant, which then enters remote rooms through pipes or air ducts. For small houses it is preferable to have a stove installed at the junction of all rooms.
If someone is not satisfied view of the iron stove, it can be overlaid brick lattice- it will improve the appearance of the oven and will not interfere with the movement of air.
Useful video
In this video, the owner of a private house tells how prolong burning sawdust in the kiln:
Results
Cheap or free sawdust effectively replace firewood or coal as fuel for heating. However it is not worth burning them in ordinary furnaces and boilers because they are designed for other fuels.
For such heating, do-it-yourself burners on sawdust are made or ordered from a master. The cost of buying or manufacturing such heaters will pay off in 5-10 years if you have the opportunity to get sawdust for free or cheap.
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