Principle of operation of a wood-fired long-burning boiler

Many of us are searching for eco-friendly, effective solutions for heating our homes. A wood-fired long-burning boiler is one such option that is becoming more and more popular. With these boilers, you can minimize your impact on the environment and maintain a warm home. But how precisely do they function?

The basic idea behind a wood-fired long-burning boiler is to burn wood in order to produce heat. But what really makes it unique is its capacity to burn wood efficiently and slowly, frequently for long periods of time. This is made possible by clever technology and design, which promotes efficient combustion and heat distribution.

The first step in the procedure is to fill the boiler with seasoned wood—usually logs or wood pellets. Because these fuels are easily obtainable and renewable, they are a desirable choice for homeowners who care about the environment. The combustion process is started when the boiler ignites the loaded wood.

Heat is produced as the wood burns, releasing energy. Through pipes or chambers, this heat is transferred to water that is circulating through the boiler’s system. The water gradually warms up as a result of absorbing heat. The hot water is subsequently distributed throughout the house via underfloor heating systems, radiators, or a combination of both.

The capacity of a wood-fired long-burning boiler to control the combustion process is what distinguishes it from conventional wood stoves or fireplaces. For ideal burning conditions, sophisticated controls keep an eye on variables like fuel supply, temperature, and airflow. By doing this, efficiency is increased, emissions are decreased, and the need for constant monitoring and refueling is decreased.

Features of wood-fired boilers

Boilers made of wood that burn for a long time have different designs, as well as differences in the dimensions of the combustion chamber. The most common materials used in the construction of these devices’ heat exchangers are cast iron or steel. Every one of the materials listed above has benefits and drawbacks. A cast-iron heat exchanger, for instance, functions steadily and cools down over an extended period of time, but it may start to deteriorate with frequent, severe temperature fluctuations. Steel heat exchangers have a longer lifespan of 10 to 15 years but are more resistant to temperature changes.

Features of wood boiler operation:

• heating of the coolant is uneven;
• carbon monoxide emitted during the operation of the device does not enter the chimney, but is a raw material for the production of combustible gas, thus ensuring environmental safety;
• the process of fuel combustion can be regulated with the help of air supply;
• During the combustion of wood material, a large amount of ash and soot is formed;
• for the operation of the boiler in the room must be a chimney;
• it is necessary to keep the wood dry, because if it is wet, its energy qualities deteriorate;
• long burning boiler and fuel must be located away from various surfaces and appliances, so the room must be free enough space.

The following benefits are associated with long-burning wood boilers:

• high efficiency, possibility to regulate the water supply temperature;
• it is possible to heat various premises and buildings;
• the possibility of using and combining different types of fuel (read also: "Long-burning wood stoves: do together");
• There is no need to connect to communications, as the heater works autonomously;
• low cost of fuel (wood).

Characteristics of wood boilers

Boilers for wood heating using solid fuel can be single- or double-circuit models. The second kind of boilers operates on a unique principle: one circuit is used for heating, and the other for DHW.

Although the technical features of various device models vary, the average indicators are as follows:

• capacity of about 100 kW;
• at the entrance to the boiler the temperature of the coolant is not less than 50 degrees Celsius;
• at the boiler outlet water temperature – 80 degrees;
• working pressure – 1 atmosphere;
• boiler weight is a maximum of 400 kilograms;
• wood, peat, coal can be used as fuel (read: "Modern long-burning coal boilers for heating");
• The maximum length of firewood is 40 centimeters;
• Efficiency is not less than 89%, this indicator varies depending on the type and moisture content of the fuel;
• duration of operation as a result of one load of firewood – approximately 12 hours.

Because they are adequately shielded from overheating, wood boilers offer a higher degree of safety. Any type of premises, including those where using an electric or gas heater is not feasible, can have them installed. Not only do these gadgets not damage the environment, but they also let you save money on home heating.

Working principle of long burning wood boilers

The device starts to function when fuel (coal, peat, or wood) smolders in the furnace. Because there is not much oxygen available, the fuel smolders for a much longer period of time—roughly 12 hours. One charge lasts 80% longer than it would in a traditional boiler, allowing wood to be used more profitably. It also allows for a reduction in the amount of time required to manage the device’s operation. A wood boiler that is suitable for dachas, individual homes, and commercial spaces will provide high-quality heating while also being reasonably priced for fuel.

A high calorific value gas forms in the hopper as a result of the prolonged smoldering process. Oxygen ignites it as it enters the combustion chamber via a refractory nozzle. Soot is among the numerous heavy and hazardous substances that burn when the boiler is operating. This way, heat is produced while burning without causing any pollution or hazardous materials to enter the chimney. Only smoke that is non-toxic and non-flammable enters the chimney.

The fuel is burned in the boiler using the top combustion principle, which states that the top layer burns first. The flame gradually goes out, which slows down the smoldering process but increases the amount of heat produced. Depending on the boiler model, operation lasts for a different amount of time after a single fuel load. As long as the temperature stays constant, the majority of appliances can function for one to two days. However, some models can run for up to three days without refueling. The picture displays the wood boiler’s connection scheme. See also: "Using their own hands to connect a TT long-burning boiler."

Long-burning boiler types and traits, in-depth video:

In understanding how a wood-fired long-burning boiler works, it"s like having a dependable friend keeping your home warm efficiently. These boilers operate on a simple yet ingenious principle: burning wood slowly to produce a steady heat supply. Here"s the magic: wood is loaded into the boiler"s firebox, where it burns at a controlled rate. This heat is then transferred to water circulating through pipes within the boiler. As the water heats up, it"s pumped through the house to radiators or underfloor heating systems, warming your space. What makes these boilers special is their ability to burn wood efficiently, often through clever designs like secondary combustion chambers or insulated fireboxes. This efficiency means less wood is needed for longer periods, reducing both cost and environmental impact. So, in essence, a wood-fired long-burning boiler is your cozy companion, keeping your home snug while being kind to your wallet and the planet.

Choosing a long burning boiler

A lot of considerations need to be made when selecting any heating device. It is important to determine in advance which indicator a boiler should have in order to efficiently heat a room in a specific area because the first consideration is capacity. Another crucial factor is the device’s efficiency.

The next step is to decide what material the boiler should be constructed of. Cast iron and steel appliances are the most popular choices. The device’s weight, heating mechanism, and power all depend on the material.

Make sure you have enough room to place the device and store fuel supplies before you purchase one. The method used to install a wood boiler varies based on the manufacturer and design. It is worthwhile to carefully inspect a device after selecting it, in order to detect any defects early on rather than while it is still operating. It is essential to adhere to all operating guidelines if you want your boiler to operate effectively and last for a long time. Moreover, only dry fuel should be used because moisture shortens the heater’s operational life in addition to reducing the amount of heat it releases.

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How to make long burning boilers on wood load 24 hours with their own hands

Long-burning solid fuel boilers are becoming more and more popular among the range of heating appliances. These stoves’ unique design ensures maximum efficiency and minimal resource usage.

We will describe the features, how to make long-burning boilers on wood loading for a full day, and what materials are required for production.

Principle of operation

The process of processing pyrolysis gases is the foundation for all long-burning boilers. The boiler is powered by solid fuels (wood chips, pellets, firewood, etc.), which smolder with little oxygen access and break down into residue and pyrolysis gas, which is then processed again. Put another way, in long-burning boilers, the fuel burns first and the gas it produces comes second. This results in a 20–25% increase in the efficiency factor and burn time of a single wood stack.

The majority of this kind of equipment is made of cast iron and steel. Specifically, the boiler’s structure is composed of steel, and the combustion chambers are cast iron. Free oxygen circulation is ensured by the open chamber, and the combustion/smoldering force is managed by a dedicated flap. The coolant circuit is situated all around the chamber.

Types of fuel

For this kind of stove, there are three primary categories of combustible materials that work well:

• wood pellets – this is a waste product from the woodworking industry (sawdust, wood chips, chaff, etc.д.), treated with a special adhesive composition and pressed under high pressure;
• coal compressed into briquettes;
• wood.

Approximately 90% of the time, wood is used, though pellets are also becoming more and more common.

When using wood in a long-burning boiler, attempt to only place the wood inside vertically. This lengthens the burn time even more.

Variety of equipment models

These boilers come in a number of varieties. Manufacturers, in particular, provide models with unique accessories, which in the end makes stove operation simpler. Among them are:

• adjustable doors – ensure maximum efficiency;
• electric heater, up to 2 kW – makes it possible to avoid defrosting in case of complete combustion of wood;
• a circuit for rapid cooling of the chamber – this emergency temperature reduction provides a high level of boiler safety;
• rotating nozzles – performs guaranteed afterburning of all emitted gases. The rotation function greatly simplifies cleaning.

What manufacturers offer

Consumer demand for long-burning wood-burning boilers that can handle a single load in a day is high right now. The profile market offers a wide variety of models made by different manufacturers. Let’s think about the best-selling items.

"Ogonyok"

This Ukrainian brand is used to produce a variety of models:

• with a turbine for air injection;
• with a circuit for heating water;
• With a top part, on which you can cook food;
• and even with towel rails.

The equipment has ten to one hundred kilowatts of power. Three of them in particular merit special attention if we are discussing individual models:

• PDGB – the essence of its operation consists in gas generation, as a solid fuel is suitable for everything except coal. Provides heating of the air;
• KOTV – the part through which the loading of firewood is carried out is quite wide, into it passes logs up to half a meter long;
• KOTV-30DT – there is a turbine for air injection, thanks to which the combustion time increases, and the temperature increases significantly.

Although it is the least expensive long-burning boiler, it has excellent qualities.

"Aton"

Long-burning solid fuel boiler in Ukraine powered by coal and wood, made of:

Products made of cast iron ATON TTK works on materials other than wood, such as

The modification designated with the letter V has an oxygen flow-boosting turbine installed for more vigorous combustion.

Steel products from ATON Tradicja. There are two varieties created:

• with manual regulation of draught intensity;
• automatic.

The primary characteristic that sets ATON TRADICJA apart is the grates’ ability to be cooled by regular tap water. This innovation allowed the designers to address the primary issue with this kind of machinery, which was the grates’ quick burnout.

The active oxygen supply provided by the modification with letter index C extends the burning time.

"Kalvis"

These are Lithuanian goods that come in a variety of forms:

• with a hob;
• mini fireplaces;
• for heating the air;
• for water circuit.

The manufacturer even sells industrial equipment, too. In any event, a unique heat-resistant material is used to cover the inside of the chamber to increase efficiency. Even an automated system for shaking off ash buildup on the grates has been designed by engineers.

pros and cons

Every piece of equipment, of course, has advantages and disadvantages. This is the topic of discussion for this section of our article.

Let us begin by discussing the drawbacks, which are as follows:

• in case of force majeure situations, it will not be possible to extinguish the flame and stop the operation of the equipment quickly;
• it is necessary to put wood in them completely – that is, it will not be possible to perform partial heating of the room;
• in the process of combustion on the walls of the tar is formed – if there is only one hatch, it is quite difficult to clean the furnace part, and it must be done monthly;
• relatively high cost. Even the most inexpensive long-burning wood boiler will cost more than a traditional one.

We could discuss the benefits of this equipment for a very long time, but we’ll focus on the following:

• high level of efficiency;
• significant savings in energy resources;
• the ability to use for heating resources of various kinds – coal, firewood, peat, seed husks, even household garbage, etc.д.;
• ease of operation – it is enough to load the fuel once and forget about the furnace for a day;
• the ability to heat the premises thanks to the heating of the air.

How to make with your own hands

The high price of this equipment is one of its drawbacks, as was already mentioned. On the other hand, long-burning boilers on wood are simple to construct by hand if you have the necessary tools, desire, and aptitude. Just pay attention to the plan and drawing. We’ll discuss it below.

What you will need: tools and materials

Get the necessary materials ready:

• used, completely empty gas cylinder;
• metal pipes;
• sheet metal.

The design requires the creation of a unique piston to press down on the combustion products in order for it to be rational and effective.

Assemble the following using the tools:

• bolgar;
• grinding disk and metal cutting disk;
• electric arc welding and electrodes;
• ordinary drill;
• drill bits for creating holes in metal.

A video demonstrating a basic DIY long-burning boiler

Manufacturing process

Once everything is ready, you can move forward. If you don’t have a cylinder, you can simply substitute it with a regular steel pipe—just make sure the walls are thick. Such a pipe should have a diameter of at least 30 centimeters and a height of approximately 85 centimeters.

Long-burning boiler scheme

A second, much smaller pipe is welded to the side in the upper section:

• diameter – 10 centimeters;
• length – 40 centimeters.

The next step is to build a piston, also called a limiter, whose main function is to apply pressure on top of the logs to stop excessive oxygen from penetrating.

You will require a pipe for this limiter:

• about 6 centimeters in diameter;
• length – slightly longer than the main one used for the boiler.

A steel disk that is slightly smaller than the boiler’s overall diameter—roughly 27 centimeters—should be welded to the lower portion of this tube.

It is also necessary to weld on the disk:

• some arc-shaped blades;
• A small gear or washer, from which the blades will diverge;
• In this gear should be made a hole, the size of which is about 2 centimeters, which will limit the volume of incoming air.

A metal cover that can be removed should be installed on the boiler’s upper portion. You can freely move the limiter inside the furnace thanks to a hole in the lid that is just a few millimeters bigger than the tube’s diameter.

You should install a metal door in the rectangle that you cut out at the bottom. The removal of the ash will be done with it.

The extra pressure causes the logs to burn as much as possible, which reduces the amount of ash that forms.

The air in the room will be fully heated by this device, but heating will only work if the area is not too big. If not, setting up a water circuit is advised, and the masters refer to this type of boiler as a Bubafonya heating boiler because it has a long combustion.

Two methods of creating a circuit

A long-burning wood-fired boiler can have its water circuit created in one of two ways. The first is very straightforward: a special water jacket is built around the entire wood combustion area.

This type of thermos has water circulation going on between its inner and outer walls.

The second, more complicated method presseurizes the wood by supplying water to a restrictor/piston. It should be noted that this option is complex in both its design and its subsequent operation. It is advised that a heat exchanger be installed in the wood burning chamber.

Additionally, the following pipes that connect straight to the tank must be installed:

• one pipe will lead the heated water into the system;
• The second method is to carry out "return", i.e. to return the already cooled water.

The way the system works will be as follows:

• the firewood is loaded into the chamber;
• are set on fire at the top;
• a limiter is installed, which will exert pressure on the logs;
• when the firewood burns through, the limiter is gradually lowered;
• by the way, the level of its lowering can also serve as a kind of signal of the need for the next load;

The water heating installation in this case is done as usual and does not differ from the traditional one.

Place of installation

The lack of necessary design and permitting documentation for installation and operation is another benefit of this equipment. This does not negate the necessity to follow the safety regulations, though.

Therefore, the following are a few of the safety requirements:

• a chimney must be created at the place of installation, effective ventilation must be provided;
• in this part of the structure, it is imperative that all fire safety regulations are observed;
• if the small loop piping is performed, it should be made with a pipe made of steel or copper;
• it is not recommended that the furnace is in contact with the walls – it is important to have a gap of about fifty centimeters;
• the room must not contain combustible materials.

By taking these easy steps, you can protect yourself and avoid uncomfortable circumstances that may result in fires.

Conclusion, reviews, tips

As you can see, long-burning boilers are a very useful and sensible invention that contributes to the provision of high-quality building heating. They are perfect for installing in different kinds of buildings:

• in residential houses;
• in summer houses;
• in greenhouses;
• in garages;
• in warehouses, industrial and manufacturing premises, etc.

Compared to other heating options, the overall cost of heating will be significantly lower. Furthermore, if you’d like, you can also save a lot of money by making the equipment yourself using the previously mentioned instructions.

The video showcases the most inventive DIY long-burning boiler ever created.

Several years ago I developed exactly such a solid fuel wood boiler (with a heat-removing jacket), which you describe in the article. Two of my friends have made it according to the drawings. One just used a large propane cylinder from under the gas, and the second decided to do on pipes 273 and 530 mm. The height of the boiler is almost 2 meters. Both are enough to heat a well-blown from the cracks of the shop area of 80 square meters.м. But! Such stoves should be fueled not with wood, they burn out quickly enough and for 24 hours will not be enough, but practically with logs. And the free space should be tamped with sawdust. In this case, the refueling is enough not even for a day, but for two days.
Now about the disadvantages. The injector burns very quickly. Steel 3 mm burns in a month, 12-millimeter sheet – in 5-6 months with every day use. If you plan to use the stove not once a year, it is better to choose thick-walled heat-resistant plates.
And I just wanted to point out. On some forum I posted my drawings and suggested that if you make it like a match – the fuel is at the top, and burns at the bottom, then you will be able to increase the burn time of the tab even more. Some time later, clever Latvian guys patented this principle. And now it turned out to be a long burning wood boiler stropuva.

Please let me know the capacity of the homemade long-burning boiler that you have drawn.

Here, the power being discussed is 10 kW.

Another query: Is heat-resistant steel appropriate given what we’ve discussed in this article and in the prior topik? Simply put, I haven’t seen any heat-resistant stoves anywhere, and it wouldn’t be very practical to buy a long-burning boiler just to disassemble it.

It is possible to ignite uranium if you create a ceramic furnace. Regarding the heat-resistant plates, I believe steel was their intended material.

Is it feasible to modify the design in any way to obtain a wood-burning boiler that runs on electricity?

No, this is the layout of a boiler that burns wood and other solid fuels for a long time. Any kind of it can be put to use. In this instance, electricity is only required to run the fan, which forces air onto the stove’s walls. Because this is a water circuit, an extra discharge is needed.

And the room is filled with smoke?

To ensure that there is no smoke left in the room at all, the piston and lid must be made with exact precision. To ensure a decent draught, the exhaust pipe is additionally at least 4 meters long. The pipe should have elbows instead of straight sections. Let it be angled at most, but not straight up.

How much time does a single charge last?

How to make a long burning boiler on your own?

Solid fuel is the most affordable of the contemporary combustible materials used in homes. Coal, firewood, peat, briquettes, and pellets fall under this category. Conventional stoves heat homes affordably and conveniently. Still, fuel must be continuously loaded. Heating an entire house with this method of operation is challenging. A water circuit-equipped long-burning boiler is a great way to solve the issue.

Supervisory structure approval is not needed for installation or operation. As a result, creating and mounting the heating unit by hand is not difficult. You will only need the boiler’s drawings, thorough construction instructions, and a small amount of money.

These are a better variety of solid fuel stoves. Strong boilers can efficiently heat commercial, auxiliary, and industrial spaces in addition to residential buildings. The slow combustion of solid fuel with a high degree of heat transfer is the foundation of the boiler’s water circuit technology. The boiler has a restricted ignition area because it is a volumetric furnace. Pellets or wood are laid every 12 to 18 hours. Robust burning is transformed into slow smoldering by controlling the air flow from above.

An exhaust pipe is used to release the exhaust gases. The water for the heating system is heated as it goes through the heat exchanger. As a result, the system runs nearly constantly and the fuel is loaded infrequently.

Energy-efficient meter with a two-month payback period!

Varieties of boilers

A great substitute for gas-fired appliances are wood-fired heating units. They have several benefits, which define them:

1. High efficiency: 90% efficiency is attained because of the fuel’s delayed combustion.

2. Extended operation: A large furnace with a strong blower fan can run continuously for up to seven days.

3. Eco-friendly: A tiny quantity of carbon dioxide is released into the atmosphere during the burning of fossil fuels.

4. Cost-effective: The integrated electronics assist in determining the best boiler loading mode.

There are three types of delayed combustion heating units available on the market today.

Uses wood, coal, or wood briquettes for operation. One charge’s combustion time is shortened by the small furnace. The fuel needs to be poured four to six times a day to ensure continuous operation. One of the main benefits of traditional boilers is their affordability.

Design featuring a large loading aperture and hopper. Bulk dry materials are utilized. The combustion process is optimized by automatic control. Operating hours for the powerful boiler vary from 6 to 24 hours, depending on the load. There is no more than 75% efficiency.

Their operation relies on the combustion of wood gases released during the gradual smoldering process. High heat transfer efficiency and quick coolant heating are provided by the design. The furnace runs on a single load until all of the fuel is burned, or 85% KDP.

Diagram showing a wood stove’s water circuit

Drawings by Vasily Pustovoychenko depict boilers as easily constructed, reasonably priced, and doable DIY projects. Use a gas cylinder, steel barrel, or solid-welded pipe as a base. Metal walls ought to be at least 3–4 mm thick. This prolongs the equipment’s continuous operation and lessens metal burnout. The base’s height ranges from 800 to 1000 mm. This parameter’s value determines the single fuel load.

The three components of the wood-fired heating boiler scheme are as follows:

• loading hopper – a container for storing fuel, the height of which changes as it burns;
• furnace chamber – the area where the slow smoldering of wood and generation of gases takes place;
• Full combustion zone – a closed pan where wood gases are burned, ash accumulates and smoke is vented.

A distribution of air surrounds the combustion chamber. This metal circle has a hole in the middle and is between 4 and 6 mm thick. It is traversed by a telescopic (or one-piece) pipe that feeds the combustion zone with oxygen. The distributor disk’s diameter is marginally less than the boiler drum because it is in motion. Air from the atmosphere enters the discharge pipe through the upper flap.

Through a chimney that is fixed in the upper portion of the chimney, the exhaust gases are released. There is a door at the base of the wall that is used to remove the ash. Since solid fuel burns almost entirely in long-burning boilers, waste is rarely removed. Furthermore, the design incorporates connecting points for the supply and return water outlets. Additionally, ascertain where the draught regulator and thermometer should be fixed.

Plumbers: This one uses a nozzle on the faucet to charge you up to 50% LESS for water.

There are two methods for heating the coolant in the water circuit:

1. Construct a remote storage tank that has a pipe within. As the exhaust gases pass through the chimney, the water is heated at the same time.

2. Go through the combustion chamber with the heat exchanger pipe. It is connected to a coil that is housed in the storage tank.

The second method has a higher efficiency. The technology used for execution, though, appears to be far more intricate.

Knowing the fundamentals of a wood-fired long-burning boiler reveals an easy-to-understand but clever procedure. These boilers work on the fundamental principle of combustion, which involves burning wood to generate heat. Long-burning boilers, in contrast to conventional boilers, are made to optimize this process’ efficiency so that the heat they produce lasts for a longer amount of time.

The fundamental function of a wood-fired long-burning boiler is to control combustion and airflow. Users can control how quickly the wood burns by changing the airflow into the combustion chamber. The boiler is able to achieve a slow and steady burn thanks to this careful balancing, which guarantees that the fuel lasts longer while still producing enough heat.

These boilers’ insulated construction, which aids in heat retention within the system, is one of its important characteristics. By keeping heat from escaping needlessly, insulation makes sure that more of the energy produced by burning wood is used to heat the water or area. This increases the boiler’s efficiency and lowers its fuel consumption, making it a more environmentally friendly heating option.

The incorporation of a thermal mass or storage tank into the system is an additional essential component. With the help of this part, the boiler can store extra heat produced during times of high demand and release it gradually as needed. Long-burning boilers can keep a steady temperature throughout the day without constantly refueling by storing heat when it’s plentiful and releasing it when needed.

Overall, simplicity, sustainability, and efficiency are the cornerstones of a wood-fired long-burning boiler’s operation principle. These boilers provide an efficient way to heat homes while reducing their negative effects on the environment and optimizing energy efficiency. They achieve this by utilizing insulation, controlling airflow, harnessing the power of combustion, and incorporating thermal storage.

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