Today, modern solid fuel boilers are quite often used today for heating a private home, despite the fact that they are inferior in ease of use to their electric and gas competitors. This popularity of this equipment is primarily due to rising prices for traditional energy resources (especially electricity), as well as the lack of centralized gas supply in some regions. We should also not forget that waste from an agricultural or woodworking enterprise is often used as fuel for solid fuel boilers, which makes heating a private home absolutely free.
Types of fuel for solid fuel boilers
The list of fuel types suitable for use in a solid fuel boiler is quite wide; it includes almost everything that is not a gas or liquid and can burn. In most cases, the heat sources are:
- coal;
- peat;
- wood briquettes;
- pellets;
- waste in the form of wood shavings and sawdust;
- husks and husks of oilseeds and grain crops;
- straw.
Each type of fuel has its own requirements for the material and design of the firebox, the air supply system and some other components of the boiler. Of course, the fuel will burn even if all these parameters do not meet, but the efficiency of the boiler in this case will be significantly lower than the maximum possible. Therefore, before choosing a suitable solid fuel boiler model, you should decide exactly what type of fuel you will use in it.
The disadvantage of household solid fuel boilers is that this equipment is not capable of operating without user participation. Even in models with automatic fuel supply, it is necessary to constantly add fuel to the storage hopper, and the owner also needs to periodically remove ash.
Features of the design of solid fuel boilers
In their simplest form, household solid fuel boilers are devices consisting of a housing, a combustion chamber located inside it and a chimney. Such boilers provide so-called air heating, that is, simply put, they heat the air around them in the same way as a traditional Russian stove does. These models have the lowest cost, but it is impossible to use these types of modern boilers for a private house with several rooms. They are suitable for small buildings consisting of one or two rooms.
To heat the coolant of a water heating system, you should use a solid fuel boiler with a heat exchanger. The heat exchanger is blown with hot gases generated during fuel combustion, due to which the water circulating through it is heated. Heat exchangers are made of steel or cast iron.
Cast iron heat exchangers are considered the most preferable: they are more durable than steel ones, are not subject to corrosion and have better performance. However, they also have some disadvantages: cast iron is much less ductile than steel, so it tolerates temperature changes less well; The cast iron heat exchanger weighs significantly more than the steel one, which complicates the transportation and installation of the boiler. The main “minus” of steel heat exchangers is the fear of corrosion.
In modern models of household solid fuel boilers, this problem is solved by adding special additives to the steel composition that increase anti-corrosion resistance. Another disadvantage is that a steel heat exchanger, unlike a cast iron one, is a welded structure:
- firstly, welds are the weak point of the product;
- secondly, this method of manufacturing a heat exchanger significantly complicates its repair.
However, steel heat exchangers offer a very useful feature, which is the use of a cooling coil. When the temperature of the coolant rises above the permissible limits, the thermostatic valve will open, allowing cold water to flow into the container. Boilers with cast iron heat exchangers cannot use this method to lower the temperature of the coolant; the system must be refilled with cool water.
Double-circuit boilers
More “advanced” models of solid fuel boilers can be used not only for heating private houses , but also for heating water in a hot water supply system. Such boilers are called double-circuit boilers. Anyone who wants to buy such a device should take into account one circumstance: immediately at the moment of using a hot water tap, the boiler completely switches to heating the DHW circuit, and the heating is turned off.
This happens as follows: as a result of switching the valves, the coolant heated by the boiler is redirected to the heat exchanger of the DHW circuit, so it temporarily does not enter the heating system. Therefore, such a connection scheme for a solid fuel boiler is justified only if hot water is consumed occasionally and in small volumes. If you need a lot of water, the water supply system is supplemented with a storage tank (boiler), which provides the following advantages:
- allows you to increase the consumption of hot water;
- makes it possible to use hot water longer without turning off the heating;
- smoothes the operating mode of the boiler, reducing the frequency of its switching from the heating circuit to the DHW.
In inexpensive models of solid fuel boilers, fuel is loaded manually, while in more advanced versions this process is partially automated. Such boilers are equipped with a hopper from which fuel is supplied to the firebox by a screw or piston feeder. Of course, such a system is unlikely to be able to supply firewood instead of the user, but with bulk fuels - fine coal (with a size of 5 to 25 mm), pellets, etc. – will cope “excellently”. The volume of one filling of the bunker is usually enough for several days.
Pellet boilers
One of the most high-calorie and easy-to-use types of fuel are pellets, which are also called biogranules. They are mainly made from wood chips, but peat, sunflower seed husks, etc. can also be used. To obtain granules, the raw materials are crushed and then pressed under pressure reaching 300 atm. Therefore, pellets occupy a much smaller volume than a portion of chips in their pure form, having the same mass. Using pellet boilers for home heating is very convenient: one load into the bunker is enough for a whole week, and the fuel burns almost completely, so you can remove ash about once a month. This equipment differs from other types of solid fuel boilers, first of all, by the presence of a special burner called a pellet burner.
Basic setup of a pellet boiler consists of the following steps:
- precise adjustment of the turn-on and waiting times of the screw feeder when supplying fuel;
- selection of the optimal fan speed for air supply;
- adjustment of operating modes of circulation pumps in heating and hot water circuits;
- setting temperature conditions.
The maximum and minimum consumption of a pellet boiler is determined by several factors:
- boiler efficiency;
- fuel calorie content;
- thermal resistance of the building envelope;
- outside air temperature;
- the number of consumers connected to the boiler in addition to the heating system (warm floor system, hot water supply).
Pyrolysis boilers
If a domestic heating boiler in a private house is supposed to be heated with coal or wood fuel, it is better to give preference to a pyrolysis or, what is the same thing, a gas generator model. Such equipment is also called long-burning boilers. Pyrolysis is the process of formation of flammable gas during the smoldering of coal or wood fuel without access to oxygen. It takes place in a special boiler chamber and is accompanied by the release of a significant amount of heat. Wood gas, consisting mostly of ethylene and propylene, is fed through a ceramic nozzle into the second chamber, where air is pumped and where it is burned. Solid fuel pyrolysis boilers for the home are very beneficial because they have increased efficiency, and besides, cleaning them requires much less effort, because there is not much ash left after pyrolysis.
Rules for choosing a solid fuel boiler
Before choosing long-burning solid fuel boilers, you should calculate their power. On average, the specific energy consumption for heating a house with an area of 100 - 150 square meters. m is 120 – 130 W/sq. m, for a house with an area of 400 - 500 sq. m – from 80 to 85 W/sq. m.
It is also worth paying attention to various improvements that can significantly facilitate the operation of the equipment. For example, heating a country house with a solid fuel boiler can be controlled by commands from a mobile phone if the boiler is equipped with a GSM module with a SIM card installed in it.
As a conclusion, we recommend watching an interesting video with a review of the operation of a cast iron solid fuel boiler.
Without a doubt, solid fuel heating is the most ancient method invented by man for heating his home. Coal, peat and firewood - such energy resources have been available to man since he began to heat his home. Today, solid fuel boilers for heating are very popular, as the development of technology and a deeper understanding of the combustion process contributes to the rebirth of such types of fuel.
Modern solid fuel boilers for heating a private home can increase the efficiency of combustion of solid fuels to 92-94 percent. Such a high figure, which was unattainable in past times, makes it possible to set up a heating system for a house without electricity or gas, using only solid energy, especially since this scheme can also act as the main heating circuit.
This article is intended to present the main types of solid fuel boilers, describes the process of selecting such equipment, and also indicates some brands of boilers.
As soon as the fuel used to heat a house or cottage is selected, it becomes necessary to decide on a boiler. All boilers operating on solid fuel are classified into the following groups: long-burning, pyrolysis, automatic, classic. Below we will describe each type of equipment separately in more detail.
Long burning boilers
Equipment such as solid fuel heating boilers for homes have special components that support long-term combustion. This combustion is usually provided by two systems: the Baltic Stropuva system, as well as the Canadian Buleryan system.
For example, the Stropuva system is a barrel up to three meters high, which is filled with firewood and closed with a movable lid with a chimney. First, the firewood is set on fire, which ensures its economical combustion, while ensuring heating of the coolant along the jacket of the barrel, and the oxygen supply is regulated automatically.
The Buleryan system is a 2-chamber wood burning stove, divided horizontally. Fuel smoldering occurs from below, gases move to the upper chamber, where they are mixed with secondary oxygen through a nozzle, and then the fuel is burned. Such a long-burning solid fuel heating boiler is an excellent solution for heating a country house or cottage.
Pyrolysis boilers
The main principle of operation of such boilers is based on the process of decomposition of fuel for gas combustion. It should be noted that a solid fuel boiler of this type is explained by the process of exposing the fuel to high temperatures with a limited volume of air. The structure of the boiler consists of 2 chambers separated by grates: the lower one is necessary for loading, as well as the combustion chamber. 
In such boilers, the combustion process is as follows: fuel must be added and ignited, after which the combustion chamber door is closed. In the upper chamber, the boost fan is activated, which serves to mix pure oxygen with smoldering gases from the lower chamber. The mixture ignites and fire is directed onto the fuel through a ceramic nozzle.
Without access to oxygen, a solid fuel heating boiler begins to burn the fuel - which creates pyrolysis, in other words, decomposition and gasification of the fuel occurs. Until the fuel burns out completely, this process will continue. Thus, heating is carried out using solid fuel.
The advantages of a pyrolysis boiler are as follows:
Despite the advantages, there are also disadvantages:
Automatic boilers
An automatic solid fuel boiler for heating a private house is the best choice, since processes such as ash removal and fuel loading are automated. Boilers of this type have a fuel supply hopper operating in automatic mode - auger or conveyor. To ensure combustion stability, fuel should be selected that is homogeneous, both in size and composition.
The advantages of this boiler are as follows:
Disadvantages of such equipment:
Classic boilers
We can say that the heating system of a private house with a classic-type solid fuel boiler represents the following operating principle: to obtain heat, the combustion process of solid fuel is carried out, as with a regular fire. The combustion process is optimized by a special grate, which ensures the supply of oxygen from below for combustion. The volume of this oxygen is regulated using the scraper settings, as well as the supply of air flows to the combustion chamber in manual mode.
Loading of solid fuel is carried out through the upper door, and through the lower one, ash is removed, as well as combustion is adjusted. The heat exchanger in the unit can be made of steel as well as cast iron.
Boiler advantages: 
- ability to work on at least 2 types of fuel;
- the ability to mount a gas as well as liquid fuel burner, regardless of electricity.
Minuses: 
Popular brands of solid fuel boilers
It is worth considering some brands of solid fuel boilers.
At the moment, the optimal choice for heating a country house is a solid fuel boiler made in Russia, Prometheus. This is due to its excellent functional equipment, operational reliability, ease of maintenance, as well as the ability to easily find any components for scheduled replacement.
When used correctly, Prometheus solid fuel heating boilers do not cause any problems to their owners.
Models are produced for both industrial and home use. They are characterized by high power, as well as dimensions. Prometheus boilers can be used both as main and backup equipment.
Boilers of this brand are produced in Russia, for this reason they are initially perfectly adapted to not very high-quality fuel and various additional difficulties during operation. The equipment is manufactured by the Sibenergotherm company, located in Novosibirsk.
If we talk about autonomous heating systems, it should be noted that decent equipment is produced in Russia, with good characteristics, and most importantly, lower cost compared to foreign analogues. Such equipment can with full confidence include the Siberia solid fuel heating boiler, which is very popular and has gained fame as a trouble-free and reliable assistant in heating a residential building.
It should be noted that if the question arises, which solid fuel boiler is better for a 100m home, then the Siberia unit will be the solution. For the most comfortable use of the equipment, you need to allocate a small room in which the equipment will be installed. In such a room you can store all the necessary tools for maintenance and a small amount of fuel, which is enough for a couple of loads.
To ensure that all these items are not stored in a living space, it is better to have a boiler room. This is especially true when heating with coal, since you have to regularly add it to the combustion chamber, and dust from coal can eat into all objects very strongly. In other words, a solid fuel boiler should not be located in a residential area.
Currently, electric solid fuel boilers for heating a private home are no less popular, the operation of which is based on the principle of burning pyrolysis gas generated in the loading chamber. The resulting gas, when entering the secondary combustion chamber at very high temperatures, transfers heat to the coolant.
The best equipment in this category includes an electric boiler from Russian developers Top 2, the functioning of which does not depend in any way on atmospheric pressure and weather conditions. The boiler doors have a fire-resistant seal that prevents flue and pyrolysis gases from entering the room. The operation of the fan motor is controlled by an electronic control unit in proportion to the operating mode of the heating pumps, boiler and DHW.
You need to know that to heat 10 square meters of area you will need 1 kW of boiler power.
It is also important to take into account the availability and cost of fuel. Installation of the unit must be carried out exclusively by specialists who have a special license to perform this type of work.
The problem of heating your own home is one of the most difficult problems that a home owner has to solve. It will not be possible to ignore this issue - it will be impossible to live in an unheated building for almost half the year, and sudden temperature changes will quickly age the entire interior decoration and shorten the service life of the entire building.
The optimal solution to the issue seems to be the creation of an intra-house system with coolant circulation through pipes and radiators installed in the premises in the required quantity. This means that the main problem is the choice of a heat generator, simply a boiler that will convert an external energy source into heating. And in this matter, based on the climate in the vast majority of Russia, the degree of availability, including price, of certain energy resources, long-burning solid fuel boilers are gaining more and more popularity.
Today, the most convenient option is traditionally considered to be installing a gas boiler. However, gas supply networks are not installed in all populated areas, and even more so in countryside holiday villages. In addition, supplying an individual line from the main line, if available, is a very serious expense.
If we add to this the inevitable approval procedures, drawing up a project in compliance with all the requirements of regulatory authorities, then such a heating method can scare off the owners of the house, especially in conditions where there is a worthy alternative.
It would seem that a very acceptable option is to use electricity. There are a lot of electric boilers produced; they are distinguished by high efficiency, ease of adjustment, rich control systems and automatic control of the heating system. But all these very significant advantages are easily broken down by the main "underwater rock"— cost per kilowatt of electricity. The average family will simply go broke on just one.
In addition, it is no secret that in villages remote from large centers, fluctuations in the power grid, alas, are not uncommon. Making yourself completely dependent on the stability of the electrical grid is probably not the best option.
Against the backdrop of the development of modern energy technologies, the traditional way for Russian open spaces to heat one’s home using ordinary firewood has gradually “faded into the shadows.” But this is a renewable source of energy, and with the lack of such fuel in vast areas of the country, there is simply no such thing. Self-procured firewood, purchased firewood, waste from wood processing enterprises, and old dead wood, which still needs regular cleaning, are used. In a word, wood was and remains probably the most accessible type of fuel in forested areas of the country.
Of course, heating with wood was never completely abandoned, and the owners carefully repaired the stoves in old houses and used them for their intended purpose. But in new buildings, the installation of a stone stove or fireplace is done more as a tribute to fashion, and not for the purpose of a complete transition to solid fuel.
However, oven oven - it retains heat for a long time due to thick brick walls and a well-thought-out system of channels for the exit of wood combustion products. It can be heated once a day to ensure an acceptable microclimate for living in the room. But what about water heating circuits? If you simply constantly maintain a fire in the boiler firebox, as in a conventional wood-burning stove, then it will be ruinous in terms of fuel consumption, and also extremely tiring - every 2 — 3 hours, or even more often, add a new portion of firewood. However, a solution was found - this was embodied in the creation of long-term combustion.
A special design of the heating device, based on those used during its operation physico-chemical properties of solid fuel, allows you to load firewood no more than once every 12-15 hours, and in some models this period is even longer, and sometimes even several days.
The advantage of such boilers is that many of them can use other types of fuel, in addition to firewood. These could be, for example, compressed briquettes from wood waste - pellets, which can be purchased in a store, and in some cases, even made independently.
Pellets - granular fuel for long-burning boilers
Coal or peat are used for solid fuel boilers. Recently they have become popular so-called “eurowood”.
Wood waste processing product - briquettes or “eurowood”
It is also a product of processing waste from the wood processing industry, has high energy intensity and is very convenient to use.
Operating principles of long-burning boilers
The principle of operation of a conventional solid fuel stove is probably known to everyone. Firewood (coal, briquettes) is placed in the combustion chamber, and from the ash chamber located below there is a flow of air containing oxygen necessary for the combustion process. The combustion intensity is limited only by the volume of incoming air and the area of the outer surface of the fuel fill.
In essence, this is an ordinary fire, only enclosed in stone or metal walls, and requiring constant replenishment of the fuel supply. In this case, combustion products are almost directly discharged into the chimney system, the labyrinths and turns of which only improve heat transfer to structural elements and, in a certain wall, lead to an increase in efficiency, but cannot in any way increase the overall energy return from a particular type of fuel. The process of thermal decomposition of wood is very intense and fleeting, leaving quite a lot of waste and releasing unused opportunities into the atmosphere.
And these possibilities lie in the special properties of wood, which are determined by its biochemical composition. During the heating process, this material does not simply oxidize to the state of coal with the release of ordinary carbon dioxide (CO2) and carbon monoxide (CO). High-temperature exposure always leads to the synthesis of volatile hydrocarbon compounds with a complex chemical formula, and they themselves are an excellent gaseous fuel, which in conventional furnaces is simply released into the atmosphere.
The process of thermal decomposition of wood is called pyrolysis, respectively, the hot gaseous components released during this process are called pyrolysis gas. It is characteristic that the temperature of its combustion, and therefore the heat transfer, is incomparably higher than that obtained during ordinary combustion of wood. At the same time, the oxidation processes of wood are so deep that after them there is practically no waste left in the form of ash, and after combustion of the gaseous component, mainly water vapor and carbon dioxide are released into the atmosphere.
This means, from the point of view of the technology for the most rational use of wood fuel, it is advisable to minimize the process of open combustion, to achieve maximum release of pyrolysis gas, which, during combustion, will, in fact, be the main source of thermal energy. It is these principles that are incorporated into the design of long-burning boilers.
Types of long-burning solid fuel boilers
So, as has probably already become clear from the principle of operation, the main technological problem that must be solved for its correct operation is dosing the flow of air into the chamber for preliminary thermal decomposition of firewood and adjusting the flow of the resulting pyrolysis gases and secondary heated air for their combustion in the main combustion chamber, where, in fact, the main heat exchange with the heating circuit is organized.
Despite the generality of the problem, in different models it is technically solved in its own way.
1. One of the options are designs in which air is pumped using a built-in fan, and the flow is adjusted by an automation unit.
Most of these boilers are arranged in such a way that the fuel loading and pre-combustion chamber is located on top.
After ignition of the stored firewood, the air supply to it is reduced to a minimum, and the fan provides air flow through the lower chamber of the main afterburning, which is made of heat-resistant materials (fireclay or ceramic concrete), which do not allow metal parts to quickly burn out and, in addition, become good heat accumulators. The created draft constantly “sucks” the resulting pyrolysis gas into the lower chamber. It is equipped with ceramic nozzles at the inlet that can withstand extreme temperatures of more than 1000 degrees Celsius.
Burning pyrolysis gases provide the main heat exchange with the pipes or “jacket” of the water circuit. Circulation, which is usually also connected to the boiler automation unit, ensures the movement of coolant through the pipes and radiators of the heating system.
If you look at the video presented, you can even visually compare the very intense burning of firewood in the loading chamber (almost at the level of sluggish smoldering) and the incomparable power of combustion of pyrolysis gas in the main combustion chamber.
Video: design and operation of a long-burning pyrolysis boiler « Motor Sich«
This arrangement of chambers is not at all a “dogma” for this type of long-burning boilers. For example, in boilers of the “Gefest-profi” model range, the afterburner chamber is moved to the rear.
It has a complex labyrinth design, which promotes the most efficient heat exchange with the heating circuit. Due to this, a very high efficiency is achieved - up to 90 ÷ 93%, almost all the heat is spent on heating the coolant. This is also evidenced by the fact that the temperature of the gases at the outlet of the chimney is only about 70 - 110 degrees.
The mentioned boilers with electronic regulation are good for everyone, however, they have a very significant drawback. They are completely energy-dependent - when the power supply is turned off, the fans and the automation unit do not operate, which means that the entire heating system becomes inoperative, even if there is natural coolant circulation in the house through the circuit. Of course, there is a way out - installing an uninterruptible power supply system, but it is good for emergencies. If power outages are a frequent occurrence, then you will have to choose some other option.
Such boilers are also very picky about changes in mains voltage - the automation may not work correctly, and they often require the installation of a separate stabilizer.
2. Non-volatile long-burning boilers, in which controlled air circulation is organized due to natural draft, are free from such disadvantages. An example of such heating devices is the “Trayan” model, popular among consumers, of the Russian trade and production association of the same name, and the “Burzhuy-K” model of the Kostroma plant “Teplogarant”.
The main advantage of such boilers is complete energy independence
They have an extensive loading chamber located at the bottom, and under it there is a ash pan- everything is like in a classic oven. The damper on the door below for air access is mechanically (via a chain) connected to a bimetallic thermostat.
After loading firewood and igniting it, the damper is opened to the maximum - this is necessary for reliable combustion of the fuel to begin and pyrolysis processes to begin, which require a temperature of at least 200 degrees.
Then the damper closes in such a way as to minimize the flow of oxygen into the wood burning zone, and the chamber switches to smoldering mode. The air, having passed through special channels for the necessary heating to the desired temperature, enters the upper chamber. It is supplied through special tubes containing calibrated holes. Coming out through these unique burners, oxygen in the air enters into an oxidative reaction with the pyrolysis gas rising from the combustion chamber. Its effective afterburning occurs with the release of a large amount of heat, which is spent on heating the coolant circulating through the pipes and the water “jacket” of the boiler.
Video: diagram of the design and operation of a long-burning boiler of the “Trayan” type
The boiler is completely energy independent, so it can be used in the absence of electricity in an open or closed heating system with natural coolant circulation.
To be fair, it should be noted that such a scheme still causes a lot of criticism from experts. It’s difficult to argue here - indeed, according to to his The efficiency and economical consumption of firewood is seriously inferior to boilers with electronic regulation and forced creation of air flows and pyrolysis gases. However, independence from electricity and ease of operation make such boilers very popular among Russian consumers.
3. Another technological approach to providing solid fuel with subsequent afterburning of pyrolysis gas is to create conditions so that the wood burning process proceeds from top to bottom, only in a relatively thin layer of loading. This principle, for example, is applied in the popular and proven efficiency boilers of the “Stropuva” model range from the Lithuanian company of the same name.
These boilers have the characteristic shape of a vertical cylinder. They can use almost any type of solid fuel - firewood, sawdust, wood chips, coal, briquettes, etc. An impressive loading chamber allows them to work on one tab for a very long time. So, on one load of firewood, the boiler, depending on the specific model, can operate from 1 to 3 days, and on coal this period is even more impressive - from 3 to 7 days.
The secret lies in the design of the boiler:
- Through the window (6) the available fuel is loaded into the combustion chamber (8). Then surface ignition is carried out using ordinary flammable oven fluids. As soon as combustion has begun, an air distributor (7) is lowered onto the fuel bed - it will dose oxygen only to the upper burning layer. Its design includes special channels that promote uniform distribution of air flow over the combustion area.
- In order for the process of surface combustion with its accompanying pyrolysis to proceed as efficiently as possible, the air needs preliminary preparation - heating to a certain temperature. A special chamber (2) is provided for this purpose. It is connected to the distributor by a telescopic air duct. Thus, the distributor gradually lowers as the fuel burns under the force of its own gravity and is constantly located in the upper burning layer.
- The released pyrolysis gases are burned in the upper part of the chamber (5). For this purpose, additional air is supplied through the damper (4). It has several positions designed for different types of fuel - coal or firewood.
- After the gases are burned, the residual combustion products are discharged into the chimney through the pipe (3).
- General regulation of the combustion intensity, and therefore the released thermal power of the boiler, is carried out by an air damper (1), connected to a bimetallic regulator, on which the set value is set.
- The boiler is enclosed in a water “jacket” for heat exchange with the heating circuit - for this there are pipes for supplying heated coolant (10) and “return” (11).
- The inspection window (9) is used for regular cleaning of the firebox from ash deposits.
Video: design and operation of a long-burning boiler " Stropuva»
Some powerful models of Stropuva boilers can be equipped with a fan for forced air supply. However, all of them are quite capable of functioning on natural draft, which makes these heating devices completely independent of the availability of electricity.
The design of the boiler is so effective that it has become the basis for numerous independent developments carried out by folk craftsmen. So, it was “Stropuva” that probably became the prototype of the currently popular one. Its structure, correct calculation and self-production technology are described in detail in the corresponding publication on our portal.
4. The duration of autonomous operation of the boiler can also be ensured by the automation of the supply of solid fuel to the combustion chamber. This scheme is implemented in boilers using granulated wood waste - pellets - as fuel.
In essence, this is the same long-burning boiler, which has several combustion chambers, but is additionally equipped with a special bunker for loading granulated fuel. Continuous supply of pellets into the firebox is carried out by means of a rotating flexible or rigid auger.
Special photos and temperature sensors monitor the intensity of combustion and the presence of fuel, generating appropriate control signals for the timely supply of pellets to the combustion area in the required quantity.
This scheme is considered very effective and has broad prospects. Its main disadvantage is its complete dependence on electricity supply. However, such boilers can easily be converted to conventional manual loading of firewood or coal. The system is quite complicated to install and adjust. And one more disadvantage, which so far limits the wide distribution of such boilers, is the currently unsaturated market for granulated fuel; certain problems may arise with its acquisition. Before installing such a boiler, in order not to waste a lot of money, you should guaranteed secure a reliable supply of pellets from their manufacturer.
Video: advantages of a pellet boiler with automatic fuel supply
Let's sum it up
So, it is too early to write off solid fuel boilers as outdated, irrelevant heating equipment. Thanks to modern innovative technologies, they have received a “second wind” and freely compete with other types of boilers - gas and
- Long-burning boilers have a solid efficiency, reaching up to 90 - 95% in some models. Heat losses, thanks to thoughtful afterburning processes of pyrolysis gases and the design of heat exchangers, are minimized. In terms of efficiency and economy, they are in no way inferior to gas ones.
- Emissions from such boilers into the atmosphere do not pose a threat to the environment; all components - water vapor and carbon dioxide - are easily absorbed by plants.
- Availability of fuel and autonomy, independence from the presence of gas mains is one of the main advantages of such equipment. There is no need for tedious permitting procedures when installing a boiler. In regions where there is no shortage of firewood, this is the best option for organizing home heating.
- Boilers can have a built-in second circuit for hot water supply to the house. Even if it is not there, it is easy to connect an indirect heating boiler to them.
- Long-burning boilers are quite unpretentious and easy to maintain. When properly used, they are designed to last for several decades.
The main disadvantages of such boilers are the following:
- No matter how long the operating time from one load is, you will still have to periodically intervene in this process to replenish the fuel supply to the combustion chamber.
- Unlike electric boilers, a mandatory preventative measure is regular cleaning of the boiler from accumulated ash to prevent it from coking on the walls of the chambers.
- A solid fuel boiler requires a separate room with good ventilation and a chimney. These devices are always quite massive, so it is necessary to prepare a reinforced platform for them.
- Additional space is needed to create reserves of solid fuel with mandatory compliance with the rules for its storage. Such boilers react quite sensitively to the moisture level of the firewood. Humidity up to 20% is considered to be the limit value - if it is exceeded, a sharp loss of device efficiency is possible.
The process of designing and installing solid fuel heating differs from similar ones in that it has special requirements. Not only the characteristics of the boiler or furnace are taken into account, but also the safety rules and operating efficiency of the entire system. Knowledge of these nuances will help you do the heating of a private house using solid fuel: boilers, stoves and a chimney system.
Basic parameters of solid fuel boilers and stoves
Solid fuel heat supply is characterized by relatively low initial costs. There are affordable solid fuel home heating boilers on the market. However, the process of installing equipment and the entire system as a whole must be carried out according to certain rules.
Almost all solid fuel stoves and boilers for water heating have the same characteristics. Their knowledge and ability to correctly use information will help you choose the right equipment for heating your home. When choosing, you should pay attention not only to technical aspects, but also to workmanship. Heating boilers for homes using solid fuel must be made of special grades of steel. The thickness of the case is at least 2 mm. For the combustion chamber, heat-resistant steel with a thickness of 3 mm or more is used.
The advantage will be a guarantee from the manufacturer and seller of heating equipment. You also need to pay attention to the availability of a network of service centers for maintenance and repair. In order for reviews about solid fuel heating boilers to be only positive when choosing equipment, you should study the following parameters:
- Rated power. It is determined by preliminary heat supply calculations. To form a small reserve, heating a private house with solid fuel should have a power of 15-20% more than the calculated one;
- Heat exchanger material. The most reliable are cast iron heating boilers using solid fuel. Their disadvantage is a high rate of inertia and possible destruction under strong mechanical stress. An alternative is lighter and cheaper models with a steel heat exchanger;
- Boiler type. In addition to classic direct combustion equipment, you can choose pyrolysis or long-burning boilers.
Often they make heating boilers using solid fuel with their own hands. But to do this work you need to choose the right manufacturing scheme and materials. The advantage of such designs is the ability to adapt the above parameters to a specific heating system.
All solid fuel air heating stoves are designed to use coal, wood, fuel briquettes or peat. Exceptions are pellet boilers, which differ in design and are intended only for pellets.
Solid fuel heating schemes
The installation of heating equipment is preceded by the selection of a circuit. The heating supply configuration, system operating parameters, as well as the type of coolant depend on it. In some cases, a steam heating scheme using solid fuel is advisable. But most often they choose water heating at home.
The choice is determined by the characteristics of the house - its area, heat losses and the required temperature conditions for heating. For uniform heat distribution, it is recommended to install a solid fuel heating boiler in a water circuit. If the area of the house is small, you can use air heating. In rare cases, homemade steam heating boilers using solid fuel are used.
At the first stage of choosing an installation plan for a solid fuel heating boiler, it is difficult to decide on the type of heat supply. Currently, the most common types are the following:
- Water with natural circulation. Applicable for small private houses and cottages. This is due to the maximum possible length of the pipeline being up to 30 m. Even with a powerful solid fuel home heating boiler, the water circulation rate will be small;
- Water with forced circulation. For this type of heat supply, you can consider manufacturing a solid fuel heating boiler with a built-in pump. Thanks to this design, the heating area is significantly increased;
- Air. It can be implemented using special do-it-yourself solid fuel heating boilers, which have channels in their design for the circulation of warm air. An alternative is to install and duct systems to distribute heated air throughout the rooms of the house;
- Steam. It is used extremely rarely in autonomous heating due to the high cost of the equipment and the need for constant monitoring of the condition of the coolant. Most solid fuel steam heating schemes are designed for heating large buildings.
The best option for installing a home heating boiler using solid fuel is water heat supply with forced circulation. It has good performance and is inexpensive to maintain. You can also note a large number of schemes according to which you can independently calculate a solid fuel heating boiler.
In any heating system, regardless of the chosen scheme, safety elements must be present. For solid fuel boilers for water heating, these are air vents, drain and check valves.
Direct combustion boilers
The simplest design of a solid fuel heating boiler is the classic model. They consist of a combustion chamber, an ash pan, a heat exchanger and a chimney pipe. The transfer of thermal energy to water occurs due to the combustion of fuel in the firebox.
The advantage of such models is reliability and simplicity of design. To independently manufacture a solid fuel heating boiler of this type, you will need a minimum of tools and materials.
But along with positive qualities, these boilers have a number of disadvantages. The main one is high fuel consumption. Reviews of direct combustion solid fuel heating boilers indicate the need to constantly add firewood or coal. If this is not done, the temperature of the water in the pipes will inevitably decrease.
It should also be noted the following features of heating a private house with solid fuel using boilers of this type:
- Large indicator of inertia. The time for heating water in the pipes to the required temperature can range from 10 to 30 minutes, depending on the type of system and its characteristics;
- Problems with power regulation. As in solid fuel air heating stoves, this can only be done by limiting the air flow through the ash pan. Therefore, when designing a heat supply system, it is necessary to provide for the installation of safety devices;
- Low efficiency. Typically it is around 60-65%. This is due to the fact that some of the thermal energy escapes along with carbon monoxide through the chimney;
- Equipment. Steel and cast iron solid fuel heating boilers do not include a circulation pump, a safety group.
It is also worth noting the absence of a second circuit for hot water supply. As an alternative, you can consider the possibility of connecting a direct or indirect heating tank, if so provided for in the design. In this case, when calculating a solid fuel heating boiler, the installation of additional equipment should be taken into account.
In most cases, the design of a solid fuel heating boiler provides an operating time on one batch of wood or coal from 4 to 6 hours. The greater the combustion intensity, the shorter the time for one cycle.
Pyrolysis solid fuel boilers
To optimize fuel consumption and increase efficiency, they were developed using solid fuel. Despite the similarity of the processes occurring inside the structure, their operating principle differs from the described direct combustion models.
Such solid fuel boilers for water heating are also called gas generator boilers. Their operating principle is not based on the direct combustion of wood, but on the formation of a volatile mixture. With a relatively low temperature effect on firewood and with a minimal influx of oxygen, the process of smoldering occurs. As a result, so-called wood gas is formed. Rising through special channels, it enters the combustion chamber, where it mixes with the air flow and ignites.
The advantage of using gas-generator heating boilers for home heating using solid fuel is economical fuel consumption. On average, one batch of firewood is enough for 12-18 hours of work. In addition, pyrolysis cast iron heating boilers using solid fuel are characterized by the following qualities:
- Electrical connection. To operate efficiently, the boiler must be equipped with a fan or turbine (rare);
- Fuel quality. Before loading, the firewood must go through a drying stage. The optimal humidity for heating a private cottage with solid fuel should be 8-10%;
- Minimum volume of carbon monoxide. Most of them burn in the secondary chamber. Thanks to this, when calculating a solid fuel heating boiler, it is possible to provide a chimney of a smaller diameter. But it must be insulated, since there is a high probability of condensation forming on its surface;
- Fuel types. The design of a solid fuel pyrolysis heating boiler is made in such a way that logs, sawdust and wood waste can be used. It is important that they have the required level of humidity and do not contain foreign impurities.
To regulate the power of a do-it-yourself solid fuel heating boiler, you can connect a fan to the control unit. It will regulate the power of the device depending on the temperature indoors and outdoors. This way you can reduce fuel consumption and optimize heating performance.
You can improve the characteristics of a gas-generating homemade solid fuel heating boiler by lining its outer surface. This will reduce the thermal losses of the structure.
Long-burning solid fuel boiler
One of the alternatives to a pyrolysis heating boiler is long-burning models. This is a relatively new heating design, which is characterized by low fuel consumption and a long combustion period.
The classic installation scheme for a solid fuel heating boiler provides for significant heating of water in the heat exchanger. Currently, low-temperature systems are gaining great popularity. It is for such schemes that a long-burning boiler will be optimal. It differs from classic models in the absence of an ash pan and the method of supplying air to support the combustion process. Reviews of long-burning solid fuel heating boilers indicate their high efficiency and reliable operation.
Structurally, it consists of a large combustion chamber, occupying about 90% of the total volume of the boiler. Air is supplied through the upper pipe, which lowers under the influence of gravity as the fuel burns. In fact, a smoldering process occurs, due to which the temperature of the coolant does not exceed +70°C.
It will be useful for the consumer to know the following properties of a long-burning boiler:
- Availability of automatic traction control. This is a mechanical device that has a thermoelement in its design. When it heats up, the air flow decreases. The reverse process provokes a decrease in the temperature of action on the thermoelement;
- No electrical connection required;
- Ash removal is carried out once every 3-4 days of operation.. However, with a large amount of combustion products, a sharp deterioration in the operation of the boiler occurs;
- Combustion occurs only at the top. Thanks to this, there is a significant reduction in fuel consumption.
One of the disadvantages of long-burning boilers is their high cost. However, with proper design of the heating system, compensation of primary costs will occur after 4-5 heating seasons. It is also necessary to ensure that the structure is protected from moisture.
Solid fuel heating boilers in past times were somewhat primitive and inconvenient, but today everything has changed. Manufacturers offer consumers improved equipment that harmoniously combines high efficiency and ease of operation. Such units are used in areas where there is no gas main and where there are power outages.
Design and principle of operation of the equipment
Devices of this type are structures consisting of several main elements:
- heat exchanger - this unit transfers energy from heated water;
- combustion chamber - it is made of high-alloy steel, high-quality cast iron;
Heating schemes can include the simplest single-circuit devices and powerful units
- thermostat;
- ash pit - combustion products accumulate here;
- grate – firewood, coal, pellets are placed on it;
- cleaning hatch;
- dampers that regulate the operation of the chimney.
The principle of operation of the units is that fuel is burned in a volumetric firebox, water is heated and supplied to the system. Ash and slag fall into a special bunker and are periodically removed manually.
When developing equipment, original technical and ergonomic developments are used
Companies that produce modernized solid fuel heating boilers are trying in every possible way to simplify the operating process. Modern devices are equipped with draft regulators and thermostatic valves. Thrust regulators influence the rate of fuel combustion by opening and closing the damper. As for thermostatic valves, they consist of cooling circuits, thermostats and are designed to drain water when overheated.
This is important to know: in pyrolysis boilers, a different principle is used: in one chamber, the firewood smolders with limited access to air flow, and in the second, the resulting gas is burned.
Connection diagram for a solid fuel heating boiler
The duration of uninterrupted operation of the devices depends on how correctly the design and installation were carried out. Solid fuel boilers for water heating are devices that heat the coolant. But do not forget that there are additional elements. The standard connection diagram looks like this:
- unit;
- circulation pump - the driving force that moves water;
- expansion tank - such an element compensates for temperature expansion of water;
- buffer tank is a vertical tank whose main purpose is to accumulate excess heat. A heating system with a solid fuel boiler using a buffer is an excellent option, because the number of loads is reduced, the operating temperature of the equipment is improved, and the consumer is provided with hot water;
- safety group - three devices combined on one console: pressure gauge, Mayevsky valve, safety valve. It is designed to protect the system from airing and overpressure;
The safety group is mounted above the boiler in a vertical position
- emergency circuit - it ensures normal operation of the system in unusual situations.
The heating scheme with a solid fuel boiler can be different, because there are many nuances. For example, if the system is open, the tank is installed in the attic, on the staircase. In other cases, membrane tanks are used, which are durable vessels separated by a partition made of environmentally friendly rubber.
Tying a solid fuel heating boiler solves several important problems. These include maintaining the temperature of the coolant, creating optimal conditions for the operation of equipment, one hundred percent protection against overheating, and removing air. The heating system with a solid fuel boiler is quite complex, so design and installation must be carried out by competent specialists.
How are devices classified?
There is a wide range of equipment on the market, which differ not only in size and appearance, but also in many other indicators. Let's talk about them further.
The method of fuel combustion is a fundamental parameter of priority importance. According to this indicator, devices are divided into:
- Classic - they undergo the usual process of burning wood and coal with the release of beneficial heat.
- Pyrolysis - at high temperatures and in the absence of oxygen, flammable gas is released. Such boilers are equipped with a forcing fan and ensure almost complete combustion of pellets and firewood.
- With natural draft - the combustion process of granules and peat briquettes in such models is controlled by a thermostatic regulator.
- With additional draft - such units are equipped with fans, with the help of which air is supplied to the firebox.
This is important to know: pyrolysis equipment has significant advantages, but it is more expensive. In addition, the devices are more demanding on wood moisture.
Type of fuel - depending on this indicator, boilers can be coal, pellet, or wood. The first uses briquettes, brown and hard coal, anthracite, the second uses cylindrical granules of standard sizes, and the third uses dry firewood. There are also universal solid fuel boilers for water heating.
The material of the heat exchanger is an equally important indicator on which a lot depends. On this basis there is the following classification:
- steel units are unpretentious equipment that does not fail when exposed to high temperatures. Thanks to the introduction of modern design solutions, the devices have good efficiency and last for 20-25 years;
Steel solid fuel boilers "Viessmann Vitoligno 100-S" operate on wood logs and have an electronic control system
- cast iron solid fuel heating boilers - they are reliable, durable and resistant to corrosion. But there is one drawback: heat exchangers made of cast iron can be destroyed by sudden temperature changes.
What are the advantages of modern solid fuel boilers?
For homes that do not have gas, solid fuel boilers are ideal. This statement can be argued by the fact that the equipment has many advantages:
- profitability – the cost of fuel (peat briquettes, granulated waste from the woodworking industry) is acceptable. Therefore, a comfortable temperature is maintained in the house throughout the entire season, and the budget does not suffer much;
Solid fuel boilers are an ideal solution because they can operate on coal, straw, wood - an ideal solution because they can operate on coal, straw, wood
- high efficiency – heat is provided to rooms of any size;
- safety - this point is carefully thought out, because the devices are equipped with monitoring systems;
- long service life - this figure is 20-30 years and is directly related to correct installation and regular maintenance;
- autonomy - heating a country house with a solid fuel boiler does not depend on third-party factors: the presence of a gas pipeline, electrical networks;
- ease of placement - to set up a functional system, you need to install a heating unit, connect pipes, an expansion tank, and radiators to it;
- ease of use - modern solid fuel long-burning heating boilers are fully automated, so human participation is reduced to a minimum. Naturally, one should not forget about periodically cleaning the ash pan from waste products, since this process is carried out manually.
What to look for when choosing a heating boiler
Purchasing heating equipment involves a number of tasks that need to be resolved in advance. Therefore, before making a purchase, you need to understand the following points:
- Power is the primary parameter by which units are selected. The power of a solid fuel heating boiler is calculated using a simple formula: the area of the house is divided by 10. Why is this so? Because 1 kW of power is required for high-quality heating of ten square meters of housing.
- Heat exchanger type.
- Dependence on external factors - solid fuel electric heating boilers with a forced-air fan do not function without electrical energy. If the circulation is natural, this problem does not exist.
- Duration of work from one load.
Polish solid fuel boilers "PEREKO" are equipped with a pressurization fan, which increases the time of continuous fuel combustion
Heating a wooden house with a solid fuel boiler is the right solution if the home is cut off from the benefits of civilization. But you need to understand that correct operation of the system is possible when the design and installation of all units and components is carried out by specialists. Competent specialists know the intricacies of their work and guarantee uninterrupted operation of the equipment for many years.
Video: heating a house with a solid fuel boiler