Solid fuel boilers

Solid fuel boilers have long been a popular option for keeping our homes warm and comfortable. These boilers are common in many homes all over the world because of their well-known dependability and effectiveness in heating buildings.

But what are solid fuel boilers specifically? In a nutshell, they are heating systems that produce heat using solid fuels like coal, wood, or pellets. Solid fuel boilers use the energy from burning solid fuels to heat your home instead of traditional gas or electric boilers, which rely on electricity or fossil fuels.

The adaptability of solid fuel boilers is one of their main benefits. Because they can burn a range of fuels, homeowners can select the one that best fits their needs and budget. There is a solid fuel option to suit your tastes, whether you favor the convenience of pellets over the more conventional appeal of wood.

The affordability of solid fuel boilers is an additional advantage. Solid fuels are a more appealing option for homeowners on a tight budget because they are typically less expensive than gas or electricity. Moreover, a lot of solid fuel boilers are extremely efficient, which means they can efficiently heat your house while using less fuel, ultimately saving you money.

Advantages	1. Cost-effective heating solution 2. Can use various types of solid fuels 3. Provides consistent warmth 4. Can be integrated with existing heating systems
Disadvantages	1. Requires regular fuel replenishment 2. Needs space for fuel storage 3. Requires cleaning and maintenance 4. May produce emissions and require ventilation

Design of a gas generator boiler

• Wood emits a small amount of carbon dioxide when it burns. This process is called gas generation or oxidation.
• If the right conditions are created, the rate of combustion slows down and the amount of CO increases.
• Carbon dioxide, after mixing with air in the required proportions, forms a combustible-air mixture.
• The gas-air mixture burns well and produces additional heat energy.

• Two furnace chambers – the first one burns wood, the second one afterburning carbon dioxide.
• Air supply and combustion products removal system. Unlike conventional boilers, most gas generators utilize a broken flue duct design. Combustion products are directed to the chimney only after their heat is accumulated by the heat exchanger.

Wood waste

Specifications for gas generation

• Limited air supply – in order for gas to be produced, the air supply must be restricted, causing the wood to literally smolder.
• High temperature – wood is charred, turning into carbon and mixing with oxygen to form carbon dioxide. CO generation requires the furnace to be heated to over 600°C.
• Humidity – raw wood, when heated, produces vapor instead of carbon dioxide. Gas generation requires humidity not to exceed 20%.

Domestic solid fuel heating boilers for use in household gas generators are less picky about the quality of the wood they use. Firewood with a humidity of between 30 and 42% is permitted to be used in models with vertical loading.

Fuel consumption in gas-generator boilers

• Fuel combustion in gas-generator boilers is slower, due to the lack of intensive air inflow. When smoldering wood, less heat is released than in the case of full-fledged combustion. Lack of heat energy is compensated by the afterburning of the carbon dioxide emitted.
• Fuel consumption is reduced by 15-20% compared to classic boilers. At the same time, the amount of heat released during combustion is practically not reduced.
• The use of automation reduces fuel consumption by at least 10% more.

Is it possible to make a simple boiler into a gas-generator boiler?

• Fireboxes and afterburning chambers – the design of gas generators specifically provides for an enlarged furnace chamber. The afterburning is carried out in a separate chamber made of fireclay brick.
• The heat carrier surrounds not only the furnace, but also a broken flue duct located inside the boiler. The scheme of the heat exchanger is quite complex. The heat carrier must surround not only the furnace, but also the flue ducts.

• Limitation in the size of the furnace chamber – to create the temperature required in the process of gas generation, it will be necessary to burn wood for half an hour. All fuel will burn in about 1.5-2 hours, which negates the efficiency of the converted boiler.
• Lack of free space will lead to a further reduction of the furnace due to the installation of the afterburning chamber.

Fuel for gas-generator boilers

The fact that gas-generator boilers can run on practically any kind of solid fuel is unquestionably one of their advantages. This means that they can be filled with regular chopped firewood, wood waste of any kind (sawdust, shavings, etc.), and wood waste-derived briquettes, pellets, etc. Furthermore, because the fuel in gas generators burns almost entirely without leaving any residue, these plants are essentially waste-free.

Advantages of gas generator heating systems

The following benefits of installing heating systems powered by wood-fuel-burning gas generator boilers are clear:

1. Extremely high efficiency of fuel combustion. In any installation designed to burn wood fuel, but not using the pyrolysis effect, the efficiency cannot rise above 90 percent.
2. Gas-generator units are energy-independent and can be installed even in buildings that do not have a connection to the fixed power grid. It should be noted that during the war gas generating units were even placed on automobiles. The energy-independence of a gas generator set also reduces the cost of operation.
3. Almost any type of wood fuel can be used in the gas-generator unit, starting from classic firewood and ending with wood production waste materials. The use of wood waste, sawdust, chips and so on significantly reduces the cost of gas generator systems. However, remember that out of the total volume of fuel laid at one time, the percentage of wood waste should not exceed the value of 30 percent.
4. Large volumes of the furnace chamber allow gas-generator boilers to work for a long time from a single fuel deposit, which facilitates the operation of such an installation.

Mechanism of the boiler’s gas generator

Disadvantages of gas generator units

Even though gas generator-based heating systems and other heating systems are very appealing, they also have certain drawbacks. The drawbacks of traditional solid fuel boilers and gas-generator systems are similar in general.

Unlike automated liquid or gas systems, a solid fuel boiler has a limited degree of operational autonomy. An operator must constantly add fuel to such a boiler as it burns. Additionally, a gas generator boiler needs to be serviced and cleaned of soot on a regular basis. Decomposition products are still present in gas-generator boilers even though the organic wood fuel is nearly entirely burned.

Purchasing a system that includes a gas-generator boiler is an expensive endeavor. Rough estimates put the cost of a gas generator boiler at 1.5 times that of a traditional solid fuel boiler. But because the gas generator boiler is more efficient, the cost difference ought to be repaid in a few heating seasons.

Using only dry fuel is also required when running gas generators. The pyrolysis process can’t begin on damp wood or sawdust. As a result, a drying chamber is frequently included in gas-generator boilers so that the fuel can reach the appropriate condition there.

Guidelines for assembling a gas-generator boiler

Practically speaking, assembling the gas-generator boiler by hand is not difficult. All you need to do is meticulously follow the directions.

First action. Together, weld a 4-millimeter steel sheet to form the boiler body. The ideal shape is thought to be cylindrical. If you can locate a product with the right specifications, you can use a section of thick-walled pipe in place of steel sheet.

The body should measure between 100 and 120 cm in length and 60 to 80 cm in diameter.

Second stage. Traditionally, the gas-generator boiler is installed in a horizontal position. Therefore, the second stage of assembly is to attach to the side wall of the body stable stops from pipe scraps. Use welding for fastening.

Step three. Make sure the housing has a flap that divides the area into two blocks. This flap is something you can make with your hands. You can start with a 4-millimeter steel sheet. Using an electric drill, drill a hole in the flap about 100 mm in diameter. By now, the flap will be prepared.

Step four. Attach a steel sheet by welding it to the body’s open end. Prior to installation, drill a hole in the sheet measuring 35 by 35 cm for the firebox door. After mounting the door with the flap, weld the hinges. Make multiple holes under the door so you can adjust the airflow’s intensity.

Phase Five. Cut 1.5–2 cm diameter steel pipes into 50 centimeter segments. Join the sections you obtained at right angles. The final construction will serve as the gas-generator boiler’s internal air ducts.

Install the ducts within the building. The firebox area is where the central portion of the ducts should be situated. Fully fuse the joints.

Additionally, a steel sheet needs to be welded to the boiler body’s second open end, with a chimney hole cut in it.

Insulate the chimney as the sixth step. Asbestos-cement pipes are typically used to construct the chimney itself. For a gas-generator boiler, a chimney length of 700 cm is advised. Horizontal sections of the chimney should be avoided if at all possible, as they significantly lower the draught level.

The homemade gas-generator boiler is now fully assembled. Remind yourself to clean the chimney on time while the unit is operating. This should be done every two to three weeks, depending on how heavily the equipment is used.

Design of pyrolysis boiler constructed by hand: A device that manages the boiler circuit The door labeled B is used for loading. C: Ash pan D: Smoke outlet E: coupling intended to be used with a fuse sensor The F-spigot is fitted for the emergency line. G is the coolant supply line on circuit KV. H is the heat exchanger’s water supply, R is 3/4 inch, and K is the heat exchanger’s hot water supply. L is the circuit’s output line. KR M: Tank for expansion

The principle of operation of pyrolysis equipment

The research of experts from institutions serves as the foundation for the development of new heating system apparatuses.

At the same time, great attention is paid to the study and modeling of combustion processes of various fuels, allowing to achieve: . Cutting back on its use Raising the heat transfer coefficient decrease in dangerous contaminants in exhaust gases

1. Reducing its costs
2. Increasing the level of heat transfer
3. Reduction of harmful impurities in the exhaust gases

As a result of this effort, pyrolysis solid fuel gas-generator boilers were created, the working principle of which is based on wood’s ability to break down into gas and solid components.

They discovered that during the course of their investigation. but also highlighted the necessity of unique circumstances for the best possible pyrolysis procedure.

• Firstly, these are established conditions, such as a temperature of about 1000º C and oxygen deficiency in the combustion process
• Secondly, a certain humidity of wood used as fuel

Wood will only be able to burn and produce gas when all the necessary conditions are met. We refer to this procedure as gas generation. Because the process of producing gas from solid organic fuel is known as pyrolysis, this feature allowed for the term "gas-generating" to be applied to these solid fuel devices.

Operating principle:

It was feasible to obtain better indicators for the quantity of heat energy produced than conventional models by taking into account the peculiarities of the operation of such pyrolysis equipment. Though practically any kind of solid fuel can go through this process, the developers took into consideration that wood has the highest gas production potential.

Pros and cons

Let’s start by thinking about the benefits that gas generators offer:

• Complete autonomy of the unit, i.e. its independence from main gas pipelines, power grids and other energy sources.
• The long burning boiler is relatively environmentally friendly, as pyrolysis releases and emits into the environment much less harmful products than combustion, which is used in some other appliances.
• The processes of pyrolysis and gas combustion are practically waste-free, that is, all the fuel in the boiler is used completely and without residue, which simplifies the operation of the boiler.
• High efficiency factor, which can reach 80-85%. Classical combustion of fuel generates much less heat.
• A wide range of fuel solids.
• With automated control and a significant volume of the furnace chamber of the gas-generator boiler, human intervention can be minimal. The device will be able to work for quite a long time on one masonry and even maintain the set constant temperatures.

Let’s now discuss the drawbacks:

• Gas-generator boilers on wood at smoldering still leave some decomposition products, which are deposited on the walls of the chambers in the form of soot and soot. Therefore, the device should be constantly maintained and periodically cleaned.
• It is impossible to fully automate the operation and exclude the participation of a person, as regular deposits of material in the furnace chamber are required.
• Long-burning boiler is somewhat more expensive than a conventional gas or solid fuel boiler. But the costs will fully justify themselves after some time.
• There are some requirements to the quality of fuel materials.
• In the combustion process, smoke will be generated, which will need to be timely vented and removed. That is, the gas generator can only be installed in a room with a chimney (and it must be equipped with all the rules).
• There are also temperature restrictions. So, to minimize the risk of condensation, the indicators must be maintained within 60 degrees Celsius.
• The device must be absolutely airtight, because the leakage of gas can under certain conditions lead to fire and even explosion.

Recommendations on installation and operation of the boiler

Diagram showing the heating boiler’s connections: The room temperature regulator, the expansion tank, the batteries, the heating boiler, and the third and fourth 5-The circuit’s make-up tap

It is crucial to be able to install gas generator heating equipment correctly in addition to being able to put it together. At this point, it’s also critical to understand the fundamentals of fire safety, as breaking them can have very negative outcomes.

An illustration of how to install a boiler

These rules come in multiples, specifically:

• To accommodate the boiler it is necessary to allocate a separate boiler room;
• the boiler can be installed only on a previously arranged concrete or brick base;
• in front of the furnace chamber of the boiler must be laid a metal sheet with a thickness of 2 mm;
• there must be a distance of at least 20 cm between the boiler walls and the nearest objects for non-combustible materials and at least 30 cm for flammable and melting objects;
• ventilation should be created in the boiler room. The minimum allowable area of the vent is 100 cm2;
• the chimney of the gas-generator boiler must be insulated. Without thermal insulation, tar and condensation will start to settle on the walls of the pipe, which will reduce the service life of the product.

The independent assembly of the gas-generator boiler is therefore not complicated. All you need is a solid theoretical foundation, basic materials, a little time, and some basic tool handling skills. If you follow the directions, you will have a dependable and extremely efficient boiler that is comparable in quality to machinery used in factories.

Video – Gas-generator boiler with your own hands

Disadvantages

• The main disadvantage can be considered a high cost of solid fuel gas generator boiler, but you need to remember that operation and maintenance is cheap, and you will buy the boiler for many years.
• Increased requirements to the quality and, especially, to the moisture content of the fuel.
• Smoke extraction is required to remove the burnt substances after pyrolysis. This means that the use of solid fuel gas-generator boilers can only be used in houses where there is an opportunity for the outlet of the pipe into the atmosphere, while not causing inconvenience to neighbors. Therefore, it is hardly applicable in high-rise buildings.
• Some limitation in the temperature regime. To avoid condensation, the temperature of the water coming from the heating system should be around 60 degrees Celsius.
• It is not possible to automate the supply of solid fuel into the furnace.
• High requirements to tightness of solid fuel gas-generator boilers. Due to the leakage of flammable gas, an explosion or fire may occur.

However, certain boilers that burn coal, gas, or wood as fuel have built-in drawbacks when it comes to pyrolysis-based boilers. The benefits to drawbacks ratio supports solid fuel gas generator boilers.

What is a gas generator boiler

An energy-dependent turbocharger is present.

Boilers with gas generators run on solid fuel. They can use firewood and all of its byproducts, such as pellets and medium-fraction wood industry waste, as an energy source. Tar and sawdust are inappropriate. These solid fuel boilers function in tandem with a typical chimney, drawing air from the room where they are installed to keep the flame going. It is therefore preferable to construct a separate boiler room just for them.

These units essentially rely on energy and come with a fan. Its job is to regulate the air supply in order to keep the heating medium’s temperature at the predetermined level. Naturally, not every heater has automated modes; some are fairly basic:

• furnace;
• gas afterburning chamber;
• chimney spigot;
• primary and secondary air connections.

The proper way to take the apartment’s temperature is outlined in the service organization’s regulations. The commission’s completion is the primary requirement.

Sometimes the issue can only be resolved by insulating the panel house’s exterior walls. Go Here to Learn More.

For the yards in the firebox to flare up during ignition, primary air is required. The primary air is covered up when the flame engulfs the entire firebox. The gas afterburning chamber receives a continuous supply of secondary air via small ducts.

Single- or double-circuit gas boilers are available for wood-fired boilers. Only the heating system’s coolant is heated by a single circuit, and DHW is also heated by a two-circuit system. An additional water heat exchanger is fitted in the firebox for this reason. Water used for heating and domestic hot water systems are two distinct systems that operate separately from one another.

How the gases are generated

It is evident from the name alone that gas-generator boilers powered by solid fuels need to produce gases. What are these gases and where do they originate from? It is quite easy; pyrolysis is a process. It literally translates as "splitting under the influence of heat" from ancient Greek. The wood in this instance is divided into two parts:

The gases are produced in multiple phases.

• inorganic wood fibers (essentially wood);
• pyrolysis gases.

There must be two combustion chambers (primary and secondary) in order to meet the requirements for the release of these gases. As previously mentioned, the fuel is smoldering in the primary chamber while the pyrolysis gases are burned in the secondary chamber. The fuel needs to smolder; pyrolysis cannot occur in the event of a fire. All because wood only starts to pyrolyze when there is a lack of oxygen, and fire requires oxygen.

It matters what the temperature mode is. Various data suggest that the ideal temperature range is 200 to 800 degrees, with 500 degrees being the golden mean.

Pyrolysis gas is released from the wood when the firebox is kept at a high temperature and almost completely oxygen-free. It is extremely flammable, but the issue is that a flame is necessary for the gas to burn. Additionally, the primary furnace lacks oxygen, which is needed by the flame.

As a result, secondary air is continuously supplied to the afterburning chamber, where the pyrolysis gases are vented. After the gas has been enhanced with oxygen, it is ignited at a high temperature. Heat is naturally released during burning and is used to heat the coolant in the heating system as well as the DHW water. Conventional boilers are less efficient than gas-generator boilers because this gas is simply not released.

Principle of action

The development of pyrolysis and other gas-generating machinery demonstrated unequivocally that even low-tech household boilers can benefit from modern technology. It is safe to refer to the enhancements these units have undergone as revolutionary. What makes them up? It turned out that there is a very clever way to burn an ordinary wooden stock that divides the combustion process into two stages.

The first is wood smoldering, which happens when the combustion chamber isn’t getting enough oxygen. Alongside it comes a certain amount of heat release and, most importantly to the inventors, the formation of wood gas. We refer to this process as gas generation, or pyrolysis. Wood gas is a mixture made up of these ingredients; it does not have a specific chemical formula.

• carbon monoxide (CO3 – about 57%, CO – about 32%);
• hydrogen;
• methane;
• carbonic acid vapor;
• of unsaturated aliphatic hydrocarbons.

Under typical circumstances, approximately 200 g or 0.15 cubic meters of volatile materials are released from one kilogram of firewood. The amazing thing about wood gas is that it can be used as fuel on its own. The gas’s caloric value can reach 4800 cal/cubic meter at different stages of its generation. This gas’s combustion is the second stage of combustion that happens in a boiler with a gas generator.

Pyrolysis boilers are outfitted with a two-chamber furnace because the first stage of the process of forming wood gas and the second stage of its afterburning occur under distinct circumstances, with varying air supply. Fuel smolders and produces gas in the first chamber. Wood gas then enters the second chamber, which receives air supply and is where the gas combustion occurs, through a nozzle. The second chamber, which is the pyrolysis chamber, can be found below or above the first. Each of the options has benefits and drawbacks.

The units operating on pyrolysis technology are a type of so-called long burning boilers. This name is due to the fact that a portion of fuel in such a boiler burns longer than in a conventional boiler, giving up the thermal energy embedded in it gradually. The main advantage of long-burning boilers is their ability to work for a long time (compared to a conventional boiler) without user participation, that is, without laying a new portion of fuel. In order to prolong this period, a modern gas-generator boiler can combine pyrolysis with the principle of top fuel combustion. The advantages of the latter can be demonstrated on a visual example with two simultaneously lit matches. If one of them is turned with the head upwards and the second one with the head downwards, the first one will burn slightly longer.

Gas-generator boilers run most efficiently when they are powered by wood, but they can also run on peat or brown and stone coal.

Equipment manufacturers

Selecting sophisticated technological devices comes with some challenges. As a result, it is best to believe the technical documentation while also keeping the manufacturer’s reputation in mind. These parameters show that the following brands’ pyrolysis boilers and gas generator boilers are the most competitive in the domestic market:

• Buderus
• Junkers (Germany)
• De Dietrich (France)
• Lamborghini (Italy)

Their decision was well-considered; in addition to the superior quality of their offerings, the rated capacity of the equipment is taken into account in all documentation.

As a result, the consumer will be able to obtain accurate information from its study regarding the boiler’s operating time on a single charge as well as numerous other aspects.

In order to provide you with some orientation regarding the capabilities of this equipment, we will briefly go over a few models. For illustration, let’s look at solid fuel-powered gas-generator pyrolysis apparatuses:

• Logano (Buderus)
• CF 120 CSE (De Dietrich)

A variety of models, with an output of up to 45 kW for steel samples and 36 kW for cast iron ones, are representative of German boilers. Their effectiveness is up to 85%.

Working on a single tab takes two hours. They have an automation system with a safety limiter and an indicator for the water’s temperature.

The firewood’s 680 mm length and the integrated cooling heat exchangers are two of its unique features.

French devices have a power limit of 30 kW, which is somewhat lower. They are also less efficient than German models, with an efficiency of only 50%. However, the logs’ length is somewhat exceeded; they can reach a maximum of 800 mm.

The features listed make it clear that each has advantages of its own; the decision you make will primarily rely on your needs.

Material basis of the project

Materials for a homemade pyrolysis heating boiler will cost money, but they won’t cost as much as an industrial sample would. Prior to beginning work, you should educate yourself on boiler types and schemes, perform calculations, and decide on an appropriate course of action.

You can hire the services of companies that specialize in the calculation of heat-generating equipment if you are having trouble with this or you are not confident that the choice was made correctly. Even so, the cost will be less than that of the factory boiler.

Tools and materials

Tool and material collection starts after the technical project is approved. You’ll require:

• DC electric welding machine;
• drill;
• grinding machine;
• consumables (drills, electrodes, cutting wheel with a diameter of 230 mm and grinding wheel with a diameter of 125 mm);
• Personal protective equipment for safe work.

The chosen scheme has minimal bearing on the project’s material foundation. Require the following resources:

• 4 mm thick sheets of metal (for internal surfaces) and 3 mm thick sheets of metal (for the body);
• 57mm and 159mm diameter piping, with wall thicknesses of 3.5mm and 4.5mm respectively;
• fireclay brick;
• profiled pipes of different sizes with a wall thickness of 2 mm;
• fan;
• temperature and pressure sensor.

While certain materials might be required for the process, they won’t have an impact on the price or completion time.

Principle of operation of the gas-generator boiler

The solid fuel "Atom" heating boilers produced by JSC "Motor Sich" are not like traditional solid fuel boilers in terms of their device and combustion principle. The fundamental idea of the boiler is the thermal breakdown of solid fuel.

• in the loading chamber, under the influence of high temperature, in conditions of lack of oxygen, the generator pyrolysis gas is released from the fuel;
• Pyrolysis gas, passing through the ceramic nozzle, mixed with secondary air and then burns in the combustion chamber in the form of a white, yellow, or blue flame;
• flue gases from the combustion chamber, passing through the smoke tubes of the heat exchanger, give their heat to the heat carrier and are discharged through the chimney to the flue pipe.

Installing Adobe Flash Player is necessary in order to watch the video. Navigate to this page and press the button.

Installing Adobe Flash Player is necessary in order to watch the video. Click and open.

Safety technology

Making pyrolysis equipment on your own is really challenging, and it’s not always necessary to produce such work. The final model can be used to heat a residential home as well as a large utility room. In the latter scenario, professionals advise purchasing factory equipment.

Correct installation of the gas generator boiler is crucial. The room’s ventilation opening should have an area of roughly 100 square centimeters.

The equipment should be removed from the surface and other objects at a distance of 0.2 meters. In front of the boiler should be laid sheet metal, the thickness of which is equal to 3 millimeters. This will allow to exclude the occurrence of fire in case of falling out of combustion products such as coal or ash during the operation of the equipment and the laying of fuel. Gas-generator stove with your own hands from improvised means can be manufactured. However, it is important to place such a device on a brick or concrete base. A separate room is required. This could be a boiler room that needs to be protected from fire as much as possible. Chimney should be well insulated with insulation, so that inside from hypothermia did not form soot and other deposits.

The main characteristics of gas generator boilers

• The main difference of gas generator boilers from other analogs of heating equipment is the volume of the loading chamber. A number of manufacturers of these units significantly increase this module, thanks to such a constructive innovation, gas-generator boilers are able to function for a day or more until the next loading. Also used programmable unit, through which you can control the temperature regime, and as a whole in the room, and with the establishment of the difference for the direct supply and return flow. On the basis of input adjustments, a certain mode of operation of the pyrolysis boiler is selected.
• Gas-generator boilers are subdivided by the type of fuel. Most often, the consumer prefers universal models, in which several types of energy resources can be used at once. Although it is noticed that wood significantly increases the efficiency of the unit.
• An important point is considered and the location of the combustion chamber, which affects the performance characteristics. In most cases, the upper installation of this module indicates the energy dependence of the heating equipment, in connection with which the overall scheme should be supplemented with a generator or uninterruptible power supply in order to avoid abnormal situations in the power supply and failures in the settings program.
• Compared to other heating equipment, the installation of gas-generator boilers is much simpler, due to the lack of need to obtain a permit for installation, as well as the use of chimneys with a simple design, without height and temperature restrictions.

The principle of operation of gas-generator boilers

1. Wood is placed in the sealed firebox and ignited with the help of the igniter.
2. In the chamber temperature with the help of the burner reaches up to 200-800 degrees.
3. Oxidation of fuel takes place, in the process of which gas is released.
4. When mixed with oxygen, a combustible mixture is formed.
5. The combustible mixture is ignited, which leads to the release of heat energy.

Operation of the gas-generator boiler scheme

Pros and cons of solid fuel boilers

Let’s now discuss the benefits and drawbacks of solid fuel boilers.

Positive points

• Superior in price to gas and electric units.
• Long service life.
• Safe to use.
• No need for additional electricity or gas.
• Fuel is affordable, it can be purchased in the required quantity.
• Some models can operate for about three days with a single load.
• Environmentally friendly heating method.

Negative points

• Insufficiently high efficiency level.
• Require effort and time to clean the device, as well as to prepare and load fuel.
• The need for repeated loading, in which it is possible that smoke may enter the room.
• No thermoregulation.
• Needs a long warm-up period after a long pause in operation.
• No possibility to increase or decrease the temperature quickly.

Bastion boiler device

The Bastion gas-generator boiler is a well-established product in the home heating equipment market, suitable for heating spaces up to 1000 square meters. Multiple units can be installed in parallel to provide heating for a larger building.

It consists of two metal shells that are inserted into one another with a coolant circulating between them at an interwall distance of 30 to 50 cm. A secondary furnace on the upper tier allows for total gas afterburning. Here, secondary air is supplied as a result of the operation of nozzles. It is possible to install a draught regulator in the upper tier.

The common channel and the flue for exhaust gas exhaustion are connected by a slide damper flange located at the rear of the tank. The upper window for secondary chamber control and the loading door window are features of the gas-generator heating boiler design. Pipeline "DU-50" is used to supply heated liquid; it has a straight pipe at the top and a return pipe at the bottom for returning water.

The lower portion of the door has an opening for the air supply and an adjustable flap that can be operated manually or in tandem with the traction regulator via a chain clutch. It is feasible to regulate the working process’s intensity by shifting its position.

Gas-producing apparatus The higher tier solid fuel boilers from this brand feature a unique technological aperture for attaching the thermometer, and a safety valve is positioned behind it to guarantee operational safety.

Installing this kind of equipment is advised in boiler room spaces outfitted in compliance with the established state regulations.

Design features of gas-generator boilers

1. fuel,
2. air supplied to the chamber of generator gas formation
3. air intended for combustion of generator gas
4. flue gases,
5. coolant inlet
6. coolant outlet a. chamber of generator gas formation; b. grate; c. combustion chamber of generator gas; d.gas duct; e.smoke pump;

The furnace in gas-generator boilers is divided into two sections. The loading chamber is the first chamber (A in the figure). When there is not enough oxygen in the air, fuel enters and burns, creating charcoal and generator gas.

One firewood stack’s worth of pyrolysis takes about 12 hours on average due to the slow nature of the process. The process produces gas that enters chamber C, the second combustion chamber, which is also supplied with air, but not enough air to allow the gas to burn completely. In this instance, the flue gases are released into the chimney.

The process of formation of pyrolysis or generator gas is accompanied by the combustion of charcoal and the release of heat energy, used partly for heating the air entering the second combustion chamber, which contributes to the intensification of the gas combustion process.

Note that there are two types of modern pyrolysis boilers available:

• with the lower location of the gas combustion chamber: in this case the combustion of wood is more uniform, which ensures a uniform flow of generator gas into the combustion chamber (the scheme of such a boiler is shown in the figure)
• with lateral arrangement of the gas combustion chamber: in this case the generated generator gas is discharged to the side.

The forced draught produced by a smoke pump powers pyrolysis boilers, regardless of where the combustion chamber is located. This makes it challenging to use in places without an electricity supply because the boiler needs to be connected to the power supply network.

All pyrolysis boilers do not, however, need to be connected to the electrical grid. Diffuse burners, which in their most basic form are just metal pipes with tiny holes in which fuel breaks down and exhaust gas enters the combustion chamber through the holes, are used to ensure the naturally directed movement of pyrolysis gases.

The combustion process in these boilers needs to be manually adjusted by opening and closing the air supply flap.

Device and principle of operation

The features of both gas and solid fuel are combined in a gas-generator boiler, which operates on a more intricate and fascinating principle. Furthermore, the manner in which heat is produced is the primary differentiator. It is a pyrolysis process, not a full-fledged combustion.

Typically, a contemporary gas generator stove consists of two chambers, each of which hosts a distinct phenomenon. The production of heat is their shared objective. There are two primary stages to the process:

1. In the first chamber of the boiler the solid fuel is ignited and starts to burn. But it is more like smoldering rather than combustion, as there is almost no oxygen, which is necessary to keep the fire going. The material smolders and oxidizes, and gradually decomposes into its individual components: various resins, vapors, oils, and carbon. As a result, a gas with combustible properties is produced.
2. In the second chamber of the device, into which the gas released as a result of pyrolysis is fed, oxygen is present, and it starts the process of intensive combustion. As a result, heat is released, which provides full-fledged heating.

Because of this, two different types of fuel are used simultaneously and in parallel for heating in a gas-generator boiler, with one fuel type being used separately from the other. First, gas is produced by the smoldering of solid fuels in the absence of oxygen. The latter starts to actively burn and release heat when air is supplied.

Special water circuits are installed in a large number of solid fuel gas-generator boilers. This unit distributes water to the radiators after it has passed through two chambers. Depending on the appliance model, the control may be entirely automated or require minimal human involvement.

Pyrolysis plants from small manufacturers

You can purchase a small-scale production unit if you are unable to make the pyrolysis unit yourself and the imported models are too expensive. In the latter instance, several requirements must be met:

• Request a license for the production of this equipment. The license is not a full guarantee of purchasing reliable and efficient products, but the risk of buying low-quality equipment is significantly reduced.
• Evaluate the appearance of the unit, the quality of welds. If possible, it is necessary to look under the decorative cladding.

Attention: Metal that is at least 4 mm thick should be used for the unit’s interior walls. It is imperative to specify the cost of replacing the nozzle if ceramics were used in the production process, as this expense may account for up to 30% of the total cost of the pyrolysis unit. [Ascertain whether the apparatus is meant for closed or open heating systems.

• If ceramics was used in the production, it is necessary to specify the price of the nozzle replacement, which may be up to one third of the pyrolysis unit cost.
• Determine for which heating system is intended for this equipment – open or closed.

Advice: If possible, try to find a review from a customer who has used the equipment for a while rather than just the first year.

For instance, based on the owners’ reviews, gas-generator boilers bastion operate perfectly well in brick homes even in areas with harsh winters. Even so, a single tab’s combustion lasts for roughly five to six hours during the winter.

It must be purchased with a reserve of power. This is because fuel that is perfectly dry is not always available to consumers.

A word of caution: It is best to install these types of units in a different room when building or buying a gas-generator heating installation. Fuel particles may fly around the boiler room when this solid fuel appliance is loaded. A 40 kW unit’s chimney needs to be at least 200 mm in diameter. It needs to be completely insulated.

How and with what to heat a wood boiler of gas generator type

Every solid fuel releases some CO during the gas generation process. Wood is the material that oxidizes to produce the most gas, as demonstrated by experiments. As a result, heating the house with a gas generator boiler is best done using wood. The fuel that is used must meet a number of requirements.

For most customers, finding the right boiler furnace is the biggest challenge. Unit manufacturers advise taking the following steps in order of recommendation:

• When the air damper is open, the wood is lit with the help of a stick.
• In the normal combustion mode, the fuel continues to burn until the temperature in the furnace chamber reaches values sufficient to start gas generation.
• The damper is switched to the mode of limited oxygen supply.

The combustion process is entirely automated in heat generator models manufactured today. Fuel is ignited electrically, and automatic controls manage the oxygen supply to the furnace and the expulsion of combustion byproducts.

What wood is better for gas-generator boiler

Wood gas-generator heating boilers use even more fuel in standard combustion mode than do traditional models. Once the mode is changed to gas generation, savings are realized. The quality of the fuel used has a direct impact on the boiler’s energy efficiency.

Firewood must meet the following standards:

• Moisture not more than 20%.
• It is optimal to use hard types of wood for the furnace. Beech, oak, acacia are suitable.
• It is forbidden to fire the boiler with coal, wood waste, dust, as it leads to a decrease in the service life. This prohibition also applies to coniferous wood.

Quality wood burns more efficiently and lowers heating costs. More heat energy is released during combustion, increasing the boiler’s efficiency, energy efficiency, and duration of independent operation on a single charge. The amount of firewood used is lowered by about 30%.

Permissible moisture content of firewood

When firewood is blatantly damp, the boiler will not function. More specifically, there won’t be an option to switch to the gas generation mode—rather, there will be a regular combustion process. If the flow of fresh air is restricted, wet fuel will simply burn off.

The firewood’s moisture content ratio parameters are entirely determined by the heat generator’s design.

• Boilers with side loading – the most common solution in European models of gas-generator equipment, demanding the quality of fuel. Maximum permissible humidity is not more than 20%.
• Top-loading models – the design was first invented by domestic developers. The principle of operation of such boilers is the gradual combustion of firewood stacked in a vertical furnace chamber. The firewood, under its own weight, as the bottom layer burns out, gradually descends downward. Warm air dries the upper fuel.Boilers with top loading are able to enter the gas generation mode even at relative humidity of firewood up to 45°C. It is required that at least one third of the fuel is dry.

The quality of fuel affects the boiler’s energy efficiency. After a year of firewood drying naturally, the moisture content reaches 20%.

When it comes to heating and insulating your home, solid fuel boilers play a crucial role. These boilers are a popular choice for many homeowners due to their efficiency and cost-effectiveness. By burning solid fuels like wood, coal, or pellets, they generate heat that can be used to warm your house and provide hot water. Solid fuel boilers come in various types, including traditional stoves and modern, automated systems. They offer a reliable source of heat, especially in areas where other fuel sources might be limited or expensive. Proper installation and maintenance are essential to ensure safety and efficiency, but with the right setup, solid fuel boilers can significantly reduce heating costs while keeping your home cozy and comfortable throughout the year.

The possibility of independent manufacture of the unit

Exorbitant costs for equipment using solid fuel The pyrolysis type explains why many customers want to build their own gas generator boilers; however, detailed instructions and drawings are typically only available in a paid version.

Among the plans devised by designer Belyaev is the construction of a device with a 40 kW heat output capability. In this system, air serves as a heat carrier.

The following materials are needed to manufacture the unit pyrolysis type: asbestos cord, fasteners, profile pipes, a rod with a diameter of 20 mm, pipes with walls that must also be at least 4 mm thick. Bricks made of fireclay are required to construct the heating unit’s lining. Centrifugal fans and thermostatic control automatics must be purchased for the unit to operate both conveniently and efficiently.

The design of inventor Blagodarov Yu.л can be used to make a gas-generating boiler yourself. The group is known as Blago.

This heating unit creates the most heat possible through a prolonged burning of wood fuel.

Take note! Grates completely cover the bottom of the fuel bunkers in the Blago appliance. With a natural draught, this design promotes a high degree of combustion heat and a lengthy combustion period.

Additionally, the fuel hopper’s volume can be increased with this device without lowering the efficiency factor.

The Blago boiler offers several benefits, including complete combustion of phenolic group compounds such as alcohols, essential oils, and resins, and energy independence.

The combustion chamber’s installed rails function as superior heat accumulators. Fuel options for Blagodarov heating units include coal, sawdust, logs, and peat briquettes.

Mechanical installation works

It’s best to use the current design to create a gas-generating heating boiler, and if you’re an engineer, you can add to or alter it to suit your needs. The fact that the chambers’ volume remains constant is crucial. In the artisanal production of pyrolysis, Belyaev heating devices, with a 40 kW power scheme, are most frequently used in boilers.

Cut out the pieces as shown in the drawing, and then join them with welding to create the completed structure. Experts advise installing a limiter in the gas-generating heating boiler to regulate the air supply to the gas combustion chamber. It is a pipe that is somewhat longer than the casing’s height and has a diameter of roughly 70 mm. A flap is attached to the pipe’s end, which is positioned in the lower chamber and 40 mm from the wall.

To improve heat removal and increase contact surface, the circuit that the coolant travels through inside the appliance should be bent. Any reasonable solution that expands the heat exchanger’s contact area without compromising the chambers’ dimensions is appropriate.

Heating systems for pyrolysis are frequently designed with the assumption that air, not water, will be the heat transfer medium. It removes the possibility of system dimensioning and does not require hot air supply pipelines to be extremely tight. After assembly, the unit needs to be tested before being installed.

How to choose long burning gas-generating boilers

First things first, you need to figure out which fuel you have more of: coal or wood. If burning coal is a more acceptable option, you should get an upper combustion boiler; if burning firewood is the preferred method of heating, it makes more financial sense to purchase a lower combustion boiler because of its higher efficiency.

The most cost-effective and environmentally friendly boilers are bottom combustion models. This is because they have two or three combustion chambers, which allow for more fuel particles to be burned.

Because steel corrodes from coal combustion condensate, cast iron boilers are more resilient. Steel heat exchangers also burn more quickly. The fact that cast-iron boilers are divided into sections makes it easier to transport them in disassembled form in the event of a depressurization (steel boilers require total replacement). However, it should be noted that cast-iron parts are brittle and susceptible to shocks.

A two-circuit solid fuel boiler is a good option if you need one that can heat the house and supply hot water. It works on the following principle: when the thermal sensor is triggered, the first circuit (which heats the room) is activated; when the pressure drops, the second circuit (which supplies hot water) is activated.

The heating boiler can be connected to any operational boiler in the house. This will result in significant savings on the heat source while also supplying a steady flow of water.

To determine the boiler capacity you need, proceed from the calculation of 1 kW for every 10 square meters of floor space. m (for wall heights up to 3 m). It should be remembered that the boiler output itself varies depending on the caloric content of the fuel and its moisture content.

Selection and installation

Prioritize your selection of a gas-generator boiler by considering its features. Thus, combustion can occur at a lower or higher temperature in a vertical or horizontal furnace. These factors will have a direct impact on fuel consumption and performance, so carefully consider your options before making a purchase.

The power, which is based on the area of the heated room, is another crucial indicator. For every 10 m² of area, 1 kW of power should be available.

Installation is a task that can be completed by hand, but it is preferable to leave such a delicate operation to a professional, as they will be aware of all the specifications and adhere to the guidelines. It is permissible to install a gas generator long-burning stove in any room of the house that is large enough (up to 35–40 kW). It is preferable to designate a different room—perhaps on the basement floor—for a larger indicator. Its ideal area is between 8 and 9 m².

Finish materials for the ceiling, walls, and floor must be fireproof and non-combustible. Storage of fuel takes place in a separate room. Regarding the chimney, it is preferable to arrange it with the fewest possible bends and angles because timely and thorough smoke removal is required.

Advice: Attempting to construct a gas generator by hand is not advised. Even though it is feasible, a homemade gadget won’t satisfy all the requirements, which means it could be hazardous or release additional dangerous substances into the environment.

Think of this type of home heating option as a gas generator: it offers many benefits but also some drawbacks.

Choice of gas-generator heating wood boiler

Given the wide variety of products available, selecting the best gas-generator wood boiler can be challenging. Numerous details are considered, including power, the amount of time that can be operated between charges, the existence of extra features, and the automation of the combustion process.

It is not unnecessary to take note of the design’s inclusion of an electric fan as a backup heat source. Two-circuit heaters work well for hot water and heating.

There are models that lack the DHW circuit. Next, add to the design of the boiler indirect heating by purchasing and connecting, which will cost extra. All of this is considered prior to making a purchase of a preferred boiler model.

Hot water and heating are good uses for two-circuit units. There are models that lack the DHW circuit. Next, incur extra expenses by buying and installing an indirect heating boiler on the building. All of this is considered prior to purchasing a preferred boiler model.

Recommendations for calculating the capacity

Determined by applying the equation 1 kW = 10 m². This ratio considers the building’s characteristics, including an average heat loss and a ceiling height of no more than 2.7 meters. Additionally, consider the following factors:

• The presence of a DHW circuit – wood-fired gas-generator heating boiler for 10 kW, suitable for a house of 100 m². But, if it is planned to additionally heat hot water, 10-20% is added to the result obtained. Accordingly, you need a heat generator with a capacity of at least 12 kW.
• Additional heat loss – in independent calculations, often overlooked the lack of good thermal insulation of the building, the presence of a large number of doorways and windows. All this affects the heat costs.

Online calculators that account for a variety of subtleties, such as the house’s insulation quality, the quantity of window and door openings, the location of the heated building, etc., are useful for performing accurate calculations.

Selection by country of manufacturer

The top manufacturers of wood-fired gas generator boilers are Czech and German businesses. The same Buderus or Viessmann continue to be among the most well-liked units in spite of their high price.

The thermal characteristics and service life of domestic boilers Bastion, ZOTA, and Topol M are noticeably lower than those of their Western equivalents.

The price range for a 20 kW wood-fired heating boiler with a gas generator made in Germany is roughly 100,000–120,000 rubles. An analog domestic currency of about 40,000 rubles.

Pros and cons of boilers with gas-generator burning wood

The ability to integrate gas-generator equipment with the current water heating system is its primary benefit. Installation tasks don’t necessitate significant material expenses. A 30% reduction in fuel expenses can be achieved after connecting.

Modern technologies that make heating and combustion control as convenient as possible are widely incorporated into European unit designs.

The high cost of goods (particularly for boilers made in Germany and the Czech Republic) and the stringent fuel quality requirements are the drawbacks. Domestic consumers’ experiences demonstrate that using gas-generator equipment is not only feasible but also a financially sensible option under Russian reality.

For heating homes, solid fuel boilers are a dependable and affordable option, especially in places where access to alternative fuel sources may be restricted. Because of their adaptability, they can burn a variety of solid fuels, such as wood, coal, and biomass, giving homeowners the freedom to select the best option based on availability and personal preference.

Solid fuel boilers are an environmentally friendly alternative to older, less efficient models because of their high efficiency in converting fuel into heat, which is one of their main advantages. Furthermore, contemporary solid fuel boilers come with cutting-edge features like temperature control and automatic ignition, which improve user friendliness and minimize maintenance needs.

Even with their advantages, homeowners should think about a few things before choosing a solid fuel boiler. These consist of the cost and accessibility of fuel in their region as well as the amount of space needed for storage. To guarantee optimum performance and safety, proper installation and routine maintenance are also necessary.

In summary, solid fuel boilers provide homeowners with a flexible and long-lasting heating option that is both sustainable and efficient. Homeowners can enhance the comfort and energy efficiency of their dwellings by making well-informed decisions by comprehending their benefits and taking pertinent factors into account.

Video on the topic

Why choose a boiler KOLOSS? Buyer"s feedback on his choice.

KOLOSS PRO AUTO 400 kW HARDWOOD INDUSTRIAL HEATING BOILER FOR LARGE AREAS

Review of the industrial ultra-long burning boiler KOLOSS PRO

Industrial solid fuel boiler Teplov"y for 400 kW

Review of solid fuel boiler "Lemax" series "Forward"

Which boiler is better? Studying with Anatoly Zharpark boilers Teplodar, Zota and Thermocraft. 2025г.