Designs for supplying sawdust to the boiler room. What you need to know about wood and sawdust boilers

A universal-to-use, 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 are highly functional and can operate on one fill for several days.

Operating principle of the boiler

Today, 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 hopper 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 home. The homeowner will not have to top up the fuel every day, and if high-quality dried sawdust is used, such heaters will be as efficient and economical as possible. Some modifications, which are equipped with larger combustion tanks and additional bins 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.

DIY pyrolysis boiler

The operating features of heating devices of this type include the following:

Possibility of adjusting the air supply to the burner.
Large volume of firebox.
Increased area of the water jacket and heat exchanger.
Depending on the modification of the boiler, fuel combustion occurs from top to bottom or bottom to top.

Autonomous heating boilers using sawdust, which use the pyrolysis principle of operation, are popular. Such installations have several combustion chambers at once, allowing to significantly increase the efficiency of the equipment. In the lower firebox, 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 sawdust boilers 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.

Equipment advantages

The popularity of heating appliances that run on wood chips is largely due to the numerous advantages of this technology. Handmade A long-burning sawdust boiler has the following advantages:

Safety of use.
Ability to control raw material consumption and temperature conditions.
Environmental friendliness of the equipment.
Minimum fuel costs.
Fast heating of the room.
High efficiency.

Self-made sawdust boilers are characterized by versatility and efficiency. With the help of such heating equipment, you can easily heat a room of any size. Thanks to the simple design of the device, you can make it yourself, and subsequently you can buy fuel for free at sawmills or buy ready-made dried pressed sawdust briquettes.

One of the disadvantages of sawdust boilers is their increased requirements for fuel quality and its moisture content. You will also need to periodically clean the chimney from ash and soot. The efficiency of the equipment and its operational safety will directly depend on the correctness of such maintenance.

Solid fuel pyrolysis boiler for: wood, sawdust, shavings, chips, biomass, pellets, briquettes

Operating modes and protective systems used

Factory models of boilers operating on wood chips and sawdust are equipped with various safety systems that prevent fire of the equipment, as well as its overheating. Some models also have additional sensors that detect high levels of carbon monoxide and can detect smoke, thereby warning of the danger of fire.

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 turning on the equipment and if the required amount of fuel is available in the bunker. As soon as the coolant and air in the room warm up to the required level, the automation will independently reduce the intensity of combustion, which will ensure efficient use of fuel.

The medium power mode allows the equipment to operate for as long as possible on one load of fuel. The intensity of sawdust combustion in the firebox is regulated by increasing or decreasing the flow of air into the combustion chamber. When this mode is activated, the boiler, equipped with additional automation, can maintain the room temperature at a given level.

In the “Pause” mode, the boiler does not heat the room, and fuel combustion stops or its intensity is reduced to a minimum. Subsequently, the homeowner can quickly heat the boiler by switching it to medium or maximum operating mode.

The presence of boiler operating modes allows us to guarantee the ease of use of the heating device, increasing the safety of its operation. With an automatic control system, the homeowner can set the required coolant temperature at will, and the built-in sensors will reduce or increase the heating intensity, ensuring comfortable living in a private home.

Long-burning mine boiler 25 kW on sawdust EVERYTHING from IGNITION to DYING. 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 following requirements apply to sawdust:

Certain modifications of boilers, which have the function of auto-loading fuel from the bunker, cannot work with sawdust with a moisture content of more than 40%. Therefore, due attention must be paid to the quality of chip drying. For the convenience of loading and storing such fuel, compressed sawdust is often used, which is offered at affordable prices, which significantly reduces the cost of heating a private home.

DIY making

On sale today you can find various modifications of autonomous heating boilers that burn 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 universal boilers on their own, since the simple design of such equipment allows you to construct it even in the absence of relevant knowledge and experience.

To make a wood chip boiler with your own hands, you will need the following tools and materials:

On the Internet you can find various drawings of the design of boilers operating on sawdust and wood chips. The easiest way to make such heaters is on the basis of a pipe or gas cylinder. You just need to use durable thick-walled steel, which will ensure the durability of a self-made boiler.

At this point, the work on manufacturing the heating boiler is completed. It is necessary to carry out 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. In the future, it is possible to modernize the heating boiler, to which a hopper with sawdust and a screw mechanism for automatically loading chips into the combustion chamber are additionally mounted.

Mine boiler on sawdust

By making a homemade pyrolysis boiler using sawdust and wood chips, you can not only solve 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 industrial boilers that have one or two circuits, are completely safe to operate and are equipped with automatic control.

If necessary, it is possible to produce universal versions of autonomous heaters, which will differ in their power ratings, duration of operation from one fuel fill, as well as a number of other characteristics.

A good alternative to gas heating equipment are solid fuel boilers using sawdust and wood chips. Fully autonomous sawdust and chip boilers are suitable for heating private and industrial facilities. Boilers are especially popular among cottage owners.

How does a sawdust-chip heating boiler work?

Modern household solid fuel boilers using wood chips and sawdust are completely autonomous stations that require refueling once or twice during the entire heating season. During operation, automatic fuel supply is used into the bunker and subsequently to the burner device.

To increase efficiency, instead of the usual method of burning wood chips, the principle of gas generator or pyrolysis combustion is used. The supply of sawdust and air is controlled by sensitive automation connected to thermostats. The error in adjusting the heating of the coolant is only 1-2°C.

The principle of operation of the burner for wood chips and sawdust

A long-burning solid fuel boiler using sawdust and wood chips operates on the principle of gas generation or pyrolysis. Screw fuel supply is used. The operating principle of a sawdust-chip boiler is as follows:

The efficiency of boilers operating on sawdust and wood chips reaches 92%. The use of a lambda probe in the device allows you to adjust the performance within the range of 30-100% (depending on the actual heat needs of the room), which increases the efficiency of the station.

Systems for supplying chips and sawdust to the burner

Automatic solid fuel boilers for long burning on wood chips and sawdust with automatic loading, minimize the need for maintenance. Fuel is supplied via several screw conveyors. The submission is carried out as follows:

Using sawdust or wood chips as fuel for a hot water boiler is especially beneficial if there is a fuel source nearby: woodworking.

Automation of cleaning and ash removal

Heating systems for private houses and cottages using solid fuel boilers, burning wood chips and sawdust, provide maximum automation of work. Removing soot, cleaning the ash pan and the internal smoke channel are carried out through self-cleaning. For this purpose, the following components and systems are installed in the boilers:

The automatic ash removal system effectively cleans the boiler. Station maintenance is required no more than once every 1-2 months.

Requirements for wood chips and sawdust

It is correct to heat the boiler with sawdust that complies with GOST 18320-78. According to current standards, raw materials must contain:

No more than 8% bark.
5% rotten remains.
0.5% mineral impurities.

All sawdust undergoes mandatory double screening. After screening, raw materials with a diameter of 10 to 30 mm remain. The use of sawdust or wood chips for heating a country house or cottage that contains impurities and metal inclusions is strictly prohibited.

The boiler is able to operate on wet wood chips, but at the same time its thermal efficiency decreases. The pyrolysis process is possible only at a maximum humidity of no more than 20%.

The optimal sawdust moisture content for the pyrolysis process is 20%. This percentage of moisture contains raw materials produced in special processing plants and intended for heating.

Norms and rules for arranging a boiler room for a sawdust-chip boiler

Operation of a sawdust-chip boiler is associated with the risk of fire. When installing and subsequent use of the station, compliance with safety regulations and regulations is required. The main requirements for the boiler room are:

Electrical equipment of the boiler room, metal parts of the boiler and screw transmission, are grounded. Connection to the power supply network is carried out directly to the switchboard. They install automatic machines and RCDs. Additionally, a voltage stabilizer and an alternative power supply source (generator or) are connected.

Which heating equipment using wood chips and sawdust to choose

In addition to productivity and fuel storage volume, when choosing a suitable station, you should pay attention to the country that manufactures the equipment. The market offers boilers from European and domestic manufacturers:

Boilers from European manufacturers are distinguished by high reliability of automation and mechanized fuel supply. The stations are equipped with a self-cleaning system, have high accuracy of adjustment and are equipped with a modulation system for changing power. Among European manufacturers, systems produced by the following companies stand out:
Russian boilers - the main advantage is their low cost. On average, fully equipped systems will cost approximately 500-800 thousand rubles, compared to European analogues, the cost of which starts at 1.5 million. Russian boilers are adapted to the realities of domestic conditions. Not picky about fuel quality.
The disadvantage is a not fully thought-out fuel supply mechanism that causes malfunctions, an insufficient safety system, and minor design flaws that reduce performance.

European boilers are suitable for those who value comfort and safety above all else and are willing to pay for it. Russian equipment is a budget version, inferior in efficiency, reliability and autonomy.

Pros and cons of choosing a sawdust-chip boiler

The design of a pyrolysis boiler with automatic loading of sawdust and wood chips has several advantages and disadvantages. Judging by customer reviews, before purchasing a station, it is worth considering the following nuances:

Large footprint - the boiler is located in two adjacent rooms. Installation requires additional refurbishment of each room.
High cost - compared to a conventional solid fuel boiler, an automatic station has a price of 3-5 times more.
Autonomy – a boiler equipped with a mechanized fuel supply can operate throughout the entire heating season without stopping.
Economy – automation regulates the combustion process, choosing the most economical mode. Power modulation is possible within the range of 30-100%, which is unattainable for a conventional solid fuel boiler.

If you have enough funds, purchasing a pyrolysis boiler that runs on wood chips and sawdust is quite justified. The costs are recouped by the station's complete autonomy, high safety and operating comfort.

Sawdust boilers are increasingly used in water heating systems as a heat source. This is due to the many benefits they have. The boilers operate on wood chips and sawdust, therefore they are highly environmentally friendly. This option helps save money, especially when making the unit yourself. They have sufficient power to maintain heat in residential and industrial premises with a large area.

Due to the high price of classical energy resources and its constant increase, home owners are switching to more budget-friendly options. The cheapest types of fuel are wood chips and sawdust. And if you make a boiler from simple and affordable materials, you will get a fairly practical solution. If it is problematic to do welding work yourself, you can invite a professional welder.

Features of boiler operation

The most modern and reliable type of sawdust boilers are automated water heating systems. Their design consists of several main parts:

fuel bunker;
gas generator;
hot water boiler - consists of a combustion chamber and a heat exchanger;
automatic control system.

Modern sawdust boiler - device

The housing design includes the following elements:

firebox;
chimney;
ash pan;
heat distributor;
coil;
blower;
sensors

Depending on the building design, it can be installed entirely inside, outside, or partially installed outside.

The automatic system is responsible for the following operations:

feeding wood chips into the boiler;
supply of hot air in the combustion chamber in accordance with the volume of fuel;
temperature rise control;
firefighting.

Among the imported boilers of a similar device, we can highlight the Austrian HARGASSNER. They are especially popular in Europe for heating hotels, houses, and office buildings.

A prominent representative of domestic boilers is BIO VULKAN produced by Pyrolysis Master. The main features of these devices:

Boiler BIO VULKAN – general device

The firebox body is made of steel sheets and pipes, externally coated with heat-insulating material.
The interior is lined with fireclay bricks, which increases the heating temperature.
Sealed doors with a concrete body, large and heat resistant.
Fans supply primary and secondary air to the firebox - this is necessary for combustion.
The drum heat exchanger is protected from lime deposits by two-level water circulation.

These sawdust boilers have the highest efficiency, which is due to the installation of a five-pass heat exchanger on them. To burn fuel, a retort burner is used, which allows the use of wood waste with a fraction of up to 4 cm.

Fuel supply mechanism

Solid fuel heating boilers operate autonomously and can be done with virtually no maintenance. Sawdust is supplied using several means.

The receiver has open access to the outside of the building. It is equipped with a screw drive connected to the storage. When the bunker is fully loaded with fuel, the conveyor starts working - it supplies fuel to the mechanized compartment.

There are two types of storage, they differ in the technique of feeding sawdust into the boiler:

a hopper with an inclined base, cone-shaped, with a screw mechanism in the lower part;
agitator with blades, sawdust is loaded by rotation.

Not all fuel from the storage goes directly into the firebox. Wood chip boilers of the pyrolysis type are equipped with a drum and a screw transmission, which supply fuel in parts.

Self-production of boilers

When you need a heating device in your home, but don’t want to spend a significant amount of money on purchasing it, you can make it yourself. For this you will need:

Do-it-yourself sawdust boiler - device diagram

pipes with a round profile 4-5 cm in diameter;
rectangular pipes 60X40 mm;
welding machine;
electrodes;
Grinder.

The pipes are selected so that they fit in a boiler measuring 36x40x80 cm. Structures with a rectangular cross-section will serve as vertical posts. Round holes are created in them for attaching other elements of the device.

On the wall of the boiler with a door there will be pipelines 5 cm in diameter. For the back, you need the first four rectangles measuring 5x6 cm, and the next four rectangles measuring 4x4 cm.

To connect the pipes, holes of 5 cm in diameter are cut. Cold and hot water will flow through them.

Manufacturing process

The front and rear parts of the boiler are equipped as follows:

rectangular posts are attached by welding;
round pipes are installed perpendicular to them;
pipelines for water supply and drainage are connected;
the open ends of the pipes are closed with pieces of metal sheets and welded.

The boiler is checked for leaks - water is poured into the pipes to immediately detect leaks. If everything is in order, the device is mounted in a brick firebox. You can make it yourself using fireproof materials.

Principle of operation

The boiler is loaded with fuel from the top, from the bottom to the chimney cut. It has neither doors nor an ash pan. Chips and sawdust are compacted with a special weight made from a thick sheet of steel. A pipe is welded to it, through which air is supplied to the firebox. It passes vertically through the lid, its end comes out - the boiler is ignited through it.

The point is to burn the top layer of biomass, the whole process moves downward. This is how the water jacket heats up.

A damper is mounted at the end of the pipe - it helps regulate the air supply to control the rate of fuel combustion. During operation, sawdust becomes less and less, the load drops lower until the boiler is empty. It is released from combustion products through the chimney.

When making your own, be sure to use drawings - this makes it easier to figure out the proportions and shape of the parts. For the device to function properly, it must be assembled correctly.

Advantages and disadvantages of sawdust boilers

Any type of heating equipment has its pros and cons. The disadvantages of a sawdust boiler are related to the quality of the fuel. Sawdust has poor flowability, which makes transportation difficult. In addition, they tend to absorb moisture, so they will burn worse than wood and coal. Homemade devices do not have any guarantees of the quality of welds; their appearance is very different from their production counterparts in their ugliness.

But, nevertheless, the device also has positive qualities:

efficiency (compared to other types of fuel, since sawdust is construction waste);
high efficiency - more than 90%;
works without harm to the environment, sawdust is an environmentally friendly product;
one load of fuel can heat a house for up to 10-12 hours;
fast heating - 30 minutes after startup;
simple design.

The cost of a homemade sawdust boiler will be several times lower than a branded boiler, even if you buy all the materials for its manufacture in a store and hire a professional welder. And if some parts are found on the farm, the savings will be even greater.

Such boilers are not picky about fuel and its quality, unlike factory ones. There will be chips from pine or birch - it doesn’t matter, the resin released will not harm the device.

Main- so that attempts to save money do not bring big losses: a boiler assembled with your own hands does not meet safety requirements. It is not durable and reliable, it does not have automatic control systems, so it cannot be left unattended.

Video: Drawings of a homemade sawdust boiler

Bi-fuel boilers using wood and sawdust are especially popular among domestic consumers due to the availability of the fuel used. During operation, the principle of gas generation is used, increasing the efficiency of heating equipment to 92%.

The principle of operation of a sawdust-wood boiler

Pyrolysis combi boilers using wood and sawdust have an internal structure and a modified design that ensures maximum heat transfer and efficiency when burning fuel. The operating principle of heating equipment is as follows:

During the combustion of solid fuel, a large amount of carbon dioxide is released. The CO produced is sent to the afterburner. During transportation, an air-gas mixture is formed, burned at high temperatures. To maintain the required temperature conditions, the afterburning chamber is made of fireclay bricks.
The heated gases are not immediately discharged into the chimney, but are directed into a broken chimney channel located inside the boiler, surrounded by a coolant liquid medium. The pyrolysis process and changes in the boiler design increased the efficiency from 70% (in standard models) to 92% (in gas generating equipment).
Modulation operating mode – long-burning solid fuel boilers for firewood and sawdust use sensitive automation connected to room thermostats. Depending on the heating needs of the room, performance varies from 30 to 100%.
The use of two types of fuel - you can independently choose as the main source of heat: firewood or sawdust. The second type of fuel will be used as a reserve. After the firewood has burned out and the coolant has begun to cool, the burning of sawdust or wood chips will start automatically.

Bifuel boilers use sawdust and firewood as fuel. Working on each of these types of fuel has its own characteristics.

Wood burning

Universal long-burning solid fuel boilers can operate on wood and sawdust. But, in the case of using firewood, the thermal efficiency of the equipment increases. This is explained simply. Firewood, when burned, releases the maximum amount of carbon dioxide, which is used to generate additional heat.

Wood burning has the following features:

Fuel filling and ignition are carried out manually.
The intensity of air supply to the firebox is controlled using a damper either manually or automatically.
The autonomous operation of the boiler from one load varies, depending on the quality of the firewood and the model of the heating unit, from 6 to 24 hours.

If you compare the technical data of boilers using wood and sawdust, it is more profitable to burn with logs. The main disadvantage of using firewood is the need for constant maintenance of the hot water boiler. It is necessary to add fuel 2-3 times a day, clean out the ash and clean the combustion chamber. All work is done manually.

Burning sawdust

Sawdust combustion is carried out with maximum automation of the process. Combustion and fuel supply proceed as follows:

Sawdust enters the combustion chamber via a screw transmission. The intensity of movement of the fuel conveyor is monitored by the boiler automation. In the event of an emergency, a signal is sent to turn off the supply of sawdust.
If necessary, a mechanized fuel storage facility is organized. After connecting the bunker, the boiler is able to operate throughout the entire heating season without stopping.
Electric ignition – sawdust is ignited using a plasma arc. An optical sensor is installed in the combustion chamber to monitor the presence of flame. When it fades, the sawdust is ignited again.
Sawdust is burned with artificial air injection. A stable flame is created, heating the coolant as quickly as possible.

Along with sawdust and firewood, in dual-fuel units it is allowed to use wood chips made from hard wood with a moisture content of no more than 20%.

Proper organization of space for installing a wood-sawdust boiler

The use of dual-fuel boilers using wood and sawdust for heating private country houses, cottages, and summer cottages has become widespread. Installation of heating equipment for domestic use is carried out in compliance with established building codes and regulations, as well as the application of instructions from the PPB.

For the safe operation of a bifuel unit and the prevention of emergency situations, general requirements for the premises used for the boiler room and fuel storage, as well as for the flue gas exhaust system used, are described. I take into account the manufacturer’s recommendations described in the technical documentation.

Standards and requirements for the premises

The room used for the boiler room is selected taking into account the technical characteristics of sawdust-wood boilers. Heating equipment operates using high-temperature combustion of fuel and, if used incorrectly or if installation requirements are not followed, causes a fire.

Some PPB requirements apply to the boiler room:

Boilers with a capacity of up to 40 kW can be installed anywhere in a residential building. Modern models are equipped with a forced smoke removal system, which prevents smoke from entering the room. Boilers with a power of over 40 kW are installed in a separate room.
The boiler room is installed in a room with smooth, non-combustible floors. Dual-fuel models are heavy, requiring a foundation to be poured under the boiler.
Supply and exhaust ventilation and natural lighting are required.
The minimum area of the room is at least 8 m².
The walls and floor are lined with non-combustible materials: plaster and ceramic tiles.
It is recommended to install a warning system and smoke detectors in the boiler room.
All energy consumption points must be turned off by automatic devices installed outside the boiler room.

Some rules may vary depending on the region. Before installing a dual-fuel boiler, consult with the local fire inspector.

Organization of a sawdust and firewood warehouse

Bi-fuel pyrolysis boilers of wood-sawdust, 20 kW, consume 7-12 tons of raw materials per year. Organizing a storage facility is a challenge for almost every owner of heating equipment of this type. The PPB requirements regarding the premises used for the storage of solid fuel indicate:

The main requirement for solid fuel storage is to ensure fire safety and prevent emergency situations.

Selection of flue gas exhaust system

The pyrolysis process begins at a temperature of 600°C, sawdust and wood chips are burned at a temperature of 700-800°C. When soot accumulates in chimney pipes, a fire occurs, increasing the temperature to 1000-1100°C. The ability to withstand prolonged heating without burning or deformation is the main, but not the only criterion for choosing a chimney pipe.

For domestic heating boilers using wood and sawdust, a chimney that meets the following criteria is suitable:

Thermal insulation - for full gas generation, it is necessary to maintain stable draft characteristics and quickly reach operating power of the boiler. This is only possible with a well-insulated chimney.
Resistance to acidic substances - soot, when mixed with condensate, under the influence of high temperature, turns into acid. A suitable chimney must have internal walls that can easily withstand acidic conditions.
Minimal condensate production. The appearance of acid precipitation in a pipe is influenced by several factors: lack of thermal insulation, incorrectly selected cross-section, poor traction characteristics.

As practice shows, the best solution would be to install or. Dual-fuel boilers differ in their operating principle, degree of automation and design features. When choosing, take into account several important points:

The principle of operation is that long-burning boilers, pyrolysis type, using sawdust firewood, cost 2-3 times more than classic units, but are able to operate autonomously for several days from one fuel refill. In a conventional model, the fuel burns out in 3-4 hours.
Fuel quality– most modern equipment models require that the moisture content of firewood and sawdust be no higher than 20%. If it is not possible to purchase dry solid fuel, you should opt for top-loading mine-type models. In models with a vertical combustion chamber, the use of firewood with a humidity of up to 42% is allowed.
Degree of automation– the offered models use manual and automatic fuel loading. Boilers with autonomous fuel supply are capable of operating in autonomous mode throughout the entire heating season.
Performance– boiler power is calculated using the formula 1 kW = 10 m².
Number of circuits– single-circuit models work to heat the heating system; in double-circuit boilers, a coil for hot water supply is additionally provided.

Dual-fuel boilers are offered by domestic and foreign companies. The most popular models are from European concerns - Hargassner, Viessmann, ETA, Solarfocus, KWB, Guntamatic and Buderus, and Russian ZOTA and Teplodar.

Pros and cons of bi-fuel sawdust-wood boilers

Experience in operating dual-fuel boilers running on wood and sawdust has made it possible to identify their advantages and disadvantages. Judging by customer reviews, bi-fuel models have the following advantages:

Optimal boiler design for burning wood and sawdust. Changes in the internal structure have increased the efficiency and duration of work from one bookmark.
Mechanized fuel supply, using wood chips and sawdust, made it possible for the device to operate autonomously throughout the heating season.
Space saving - dual fuel boilers take up less space than two single fuel units.
Possibility of automatic switching to another type of fuel. After the wood burns out, the boiler begins to use sawdust. In some models, an electrical heating element is additionally installed.

Dual-fuel boilers have few disadvantages. Basically, the disadvantages are related to the operating principle used:

Gas-generating heating boilers operating on wood or sawdust are sensitive to the quality of the fuel. This minus distinguishes all pyrolysis models without exception.
Dependence on electricity - the design includes a system of forced air supply and smoke removal, a screw transmission driven by an electric motor.
When there is a power outage, the boiler stops working. You can solve the problem, or a generator.

The cost of a dual-fuel boiler is less than what you would have to pay for two equivalent heat generators that burn sawdust and wood separately. Purchasing a bi-fuel model is completely justified and cost-effective.