Many owners very often face the following problem: how can you heat your home efficiently and safely if gas is not supplied to it? There can be only one answer to this question: it is most correct to use a special installation in the form of a boiler that runs on wood according to the principle of pyrolysis combustion. You can buy such a device in a specialized hardware store, but its cost will be quite high. That is why you should consider in detail how to make a home-made pyrolysis boiler, as well as pay attention to the features of its operation.
What is pyrolysis combustion?
As you know, it is not very convenient to heat a particular room with firewood, since this fuel burns quickly, without releasing the required amount of energy. However, if the oxygen content in the furnace is reduced, the material will be consumed much more slowly. It is on this that the principle of pyrolysis combustion is based, thanks to whichsignificantly less fuel is required and efficiency is increased. The main products obtained in this case are coke, ash, and combustible gas, which also releases a large amount of heat.
This means that when designing a homemade long-burning boiler, the following points must be taken into account:
- Initially, wood burning with limited oxygen releases combustible gas;
- the resulting mixture is burned, giving off heat in turn.
Many homemade boilers work according to this principle, but it is important to remember that the equipment must be adjusted so that the overall heating system of the home is not damaged during its operation.
Design of a wood-fired boiler
The furnace of such devices is divided into two parts. The first of these is called the loading chamber. It is in this section of the boiler that the wood burns, undergoing pyrolysis. Accordingly, the volume of air here is minimal. All the gases obtained during operation enter, in turn, into the second part, which is called the combustion chamber. Moreover, it should be noted that the heat loss in this case is insignificant.
When making a homemade wood-fired boiler, you need to take into account that the separation of the two above-mentioned chambers is carried out by means of a special grate. The air entering the mechanism first completely passes through the fuel, which is typical only for pyrolysis machines.
Aerodynamic dragof such devices is very high, as a result of which it becomes necessary to install additional traction, which can function not only with the help of a conventional fan, but also with a special smoke exhauster used specifically for these cases.
Technical features of the pyrolysis boiler
The heat exerted on the wood inside the mechanism causes it to decompose, resulting in the formation of coal and combustible gas.
Homemade solid fuel boilers create a very significant amount of heat during operation. This is due to the fact that the temperature inside the combustion chamber can reach up to 1200 °C, as a result of which the outgassing is very fast. The products of combustion of the resulting volatile mixture, having given up most of the energy, are subsequently taken out through the chimney installed on the apparatus.
Due to the large volume of the loading chamber, the temperature can be maintained constant over a long period of time, which cannot be said about standard heaters. So, a home-made wood-fired boiler can function without stopping for a whole day, while it is enough to load wood into it only once. In addition, you can always adjust the power of the machine as you wish.
It is possible to clean such equipment, but rarely, since no soot is formed during operation, and ash is produced in minimal quantities.
It is also impossible not to note the environmental friendliness of these devices, since the exhaust gasesare nothing more than a combination of water vapor with carbon dioxide.
Nevertheless, it is worth mentioning some of the negative aspects of the pyrolysis boiler. So, it is customary to single out the following from them:
- the equipment is quite large, which may not be very convenient in a small room;
- for quality work it is important to use only well-dried fuel, otherwise the heat output will be much less;
- normal operation of the boiler is possible only if the network connection is stable, which is due to the need to maintain forced draft, the main mechanism of which is the built-in fan.
But, as it becomes clear, this equipment has more advantages than disadvantages, so its installation will definitely be the right decision.
Optimal fuel for a wood-fired boiler
The best heating material used in pyrolysis boilers is, of course, wood. Moreover, the ideal parameters for it are the following: length 400–450 mm, diameter 100–250 mm. It is not forbidden to burn sawdust along with logs, but it is important to remember here that such fuel should not exceed 30% of the total volume of material placed in the loading chamber.
As mentioned above, a home-made long-burning boiler will work with maximum efficiency only on dry wood, that is, one whose moisture content is not more than 40%. Moreover, such measures are not onlywill increase the power of the equipment, but also extend its service life.
Therefore, it is important to make sure that the fuel is well dried and does not contain a lot of moisture, otherwise the operation of the machine will be less efficient.
Drawings of long burning boilers
Any independent production of this or that equipment must necessarily be accompanied by consultations with various schemes of the mounted device. So, drawings of home-made pyrolysis-type boilers can be easily found both in various construction organizations involved in the assembly of such equipment, and on the Internet.
These plans usually display the location of the functional parts of the future device (furnace, chimney, heat exchanger, etc.). Often, they are also marked with the exact dimensions of the structure to be mounted, which, of course, facilitates the entire work process. The main thing is to be able to understand the drawings and follow the instructions.
Do not forget that in case of improper assembly, the device may at best not work, and at worst become a safety hazard, since any manipulation of fire, as you know, requires strict adherence to safety precautions. A poorly assembled structure can lead to unforeseen consequences, so all steps must be performed competently and carefully.
Materials for self-assembly of the boiler
In order to properly make a homemade pyrolysis boiler, you shouldhave the necessary materials and tools available. Here is a list of them:
- electric drill;
- several packs of electrodes;
- welding machine (preferably DC);
- 230mm cutting wheel;
- Bulgarian;
- 125mm grinding wheel;
- sheets of metal 4 mm thick;
- refractory brick;
- pipes of various diameters;
- several profile pipes 2 mm thick;
- fan;
- temperature display sensor;
- a number of steel strips with different thicknesses and widths.
In the case of such equipment, it is better to use 4 mm steel. However, homemade boilers can also be designed using a material 3 mm thick, which is usually done in order to save money.
Process of making long burning boiler
The assembly process begins with cutting out four walls for the future device from finished sheet steel. At the same time, using a grinder, you need to cut two holes in the front face, one of which is intended for the ash pan, and the other for the firebox.
The back of the boiler can be left untouched for now, and the remaining three must be firmly welded together. The rough seams resulting from the work should be carefully sanded with a grinder.
Homemade solid fuel boilers have a heat exchanger in their design, all components of which must also be tightly welded, and the growths that have appeared must be cleaned. Then you can start installing thisdevices directly inside the oven.
Place the firebox, unlike factory models, better at the top, not at the bottom. With the help of a grate, it must be separated from the gasification compartment located above. The combustion chamber must be lined with refractory bricks, laying it on all sides.
Then you can mount the doors, while it is important to ensure that they fit as closely as possible to the walls of the structure.
Having made a chimney, you need to fix the sensor to determine the temperature, the main function of which is to control the combustion process and display the power of the boiler.
Next, you need to cut holes intended for all pipes, fix the back wall with a welding machine and process uneven corners. The assembly process is completed by checking the operation of the finished device. The absence of carbon monoxide emissions means that the equipment is fully operational.
It is according to this scheme that the simplest home-made boilers should be mounted, the principle of operation of which is based on pyrolysis.
Recommendations for assembling a wood-fired boiler
In order to avoid serious difficulties during the manufacturing process, and the equipment subsequently works reliably, it is recommended to pay attention to the following recommendations that can help with installation:
- It is extremely important to equip the system with a restrictor that allows you to control the air entering the combustion chamber. For its design, a pipe with a diameter of about 70 mm is suitable, while having a slightly longer length compared to the bodydevice. A steel disk must be welded to the lower part of the limiter, which must be located at a distance of about 40 cm from the walls of the base, and the boiler cover must be equipped with a special recess for mounting it.
- Homemade heating boilers require a rectangular hole for loading firewood. It must be closed with a door, which is equipped with a special steel lining that provides a tighter grip on the body.
- The heat transfer pipe must have a bend. This will help make the energy return stronger.
Pyrolysis boiler operating tips
It is very important to ensure that the operation of this equipment takes place in a safe environment and does not create any danger to others. So, it is worth remembering that there are some rules governing the operation of such a mechanism. These include the following:
- home-made boilers can only be installed in non-residential buildings;
- the device should not be near walls and other objects in the room closer than 30 cm;
- for safe operation of the device, it would be better to install it on a concrete or brick base;
- it is extremely important to equip the room with the boiler with good ventilation so that the combustion products do not accumulate inside the room, but go outside;
- to protect the chimney of the appliance from condensation, it is recommended to insulate it with mineral wool.
Compliance with these simple rules will not only achievemaximize the efficiency of the boiler, but also significantly extend its operational life and eliminate the need to perform any kind of repair work.
