Solid fuel forced-air boilers. Heating with solid fuel. low efficiency of solid fuel combustion
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For a long time, in every house located in the Russian expanses, the heating stove was the most important place. Thanks to the stove, the house was warm in winter. In addition, food was prepared on them, and some structures with a bed even made it possible to sleep. In many rural huts, the stoves are still preserved. Over time, they have undergone significant changes and now owners use solid fuel, electricity or gas boilers to provide heating.
Deservedly gas heating considered the most optimal solution problems of heat supply, but, unfortunately, the mains are not laid in all settlements. Electric heating of a home is an expensive option, and an unstable power supply can lead to equipment shutdown or breakdown. Therefore, property owners, especially in rural areas, prefer to install solid fuel heat generators.
Classification of solid fuel boilers
Depending on the material of manufacture, a solid fuel heating boiler can be:- cast iron;
- steel.
The operation of all models of devices operating on solid fuel depends on the presence of water in the heating structure. If the amount of coolant in the system reaches a critical level, overheating and deformation of individual elements is possible. Steel units are more resistant to temperature fluctuations, and cast iron products are more resistant to corrosive processes.
The following information will be useful for consumers: the required volume of fuel for loading is calculated based on certain standards. For one kilowatt, steel boilers require 1.6 - 2.6 liters, and for cast iron appliances 1.1 -1.4 liters.
Thus, cast iron and steel heat generators differ not only in weight and material of manufacture, but also in other characteristics, including structural differences. So the cooling coil in steel solid fuel boilers is located inside them. When the coolant heats up to a critical temperature, you can open the thermostatic tap slightly, after which cold water will begin to flow and thereby lower the temperature.
In cast iron boilers, such as in the photo, similar elements are located on the supply. You can lower the temperature in them only by partially draining the hot water and adding cold coolant. When producing a cast iron product, its sections are assembled into a single device using steel pins. As for the steel unit, its parts are connected by welding. The strength of the seams depends on its quality.
Loading firewood, coal, pellets into solid fuel heating boilers is done manually by opening/closing the loading hatch door. Since its internal part comes into contact with fire and gets very hot, a person can get a serious burn if they come into contact with it. To prevent this from happening, cast iron units have a door with a special protective layer. For steel appliances, the door is equipped with a water-cooling circuit along the contour.
To clean a cast iron boiler from ash and ash, you will need a poker. Steel heat generators are equipped with rotating grate bars, mechanically controlled - as a result, to clean the stove you do not need to open the door to the firebox.
The design of solid fuel boilers varies. These devices are:- single-circuit;
- double-circuit.
classical (traditional) and gas generator (pyrolysis). The latest devices consist of two chambers located one above the other, which are separated by nozzles.
Solid fuel is placed in the upper part, but it does not burn immediately. Thanks to the pyrolysis process, the wood is initially dried and at the same time the air is slightly heated. As a result, efficient heat exchange is ensured. Pyrolysis boilers are equipped with a ventilation device, which not only facilitates quick combustion, but also minimizes harmful emissions into the atmosphere.
If such a bunker is filled completely, the next loading will only be required after a few days. The warranty period for these devices is about 10 years. But if the operating conditions are observed, the boiler can last a much longer period.
Safety of the heating system
The main point when a solid fuel heating boiler is installed is to prevent overheating of the heating supply structure. Since the heat generator cools down very slowly, it is necessary to avoid situations where the temperature reaches the maximum limit. This is especially true for metal-plastic and plastic elements. When the temperature exceeds 100 degrees, they can melt and the heating equipment may become unusable.
You also need to be extremely careful when draining hot water (to prevent overheating) into the sewer system if it is equipped with plastic pipes that can become deformed.
The need to install a chimney
Effective operation of a solid fuel boiler is impossible without the correct choice of installation location for the chimney, which must easily withstand high temperatures and not be subject to corrosion. It cannot be less than 4 meters in height, and 18 centimeters in diameter.Installation of the boiler and smoke exhaust system should only be carried out by professionals. But the customer of installation services does not bother to study the relevant information in order to assess the quality of the work. After installation is completed, the boiler ash pan must be regularly cleaned of accumulated ash and slag, which reduce the efficiency of the equipment.
Video about a solid fuel heating boiler:
Among solid fuel boilers, the most popular are wood-fired solid fuel boilers.
Solid fuel wood boilers
The boiler has an electric air blower, which is controlled electronic system from the thermostat. As a result of changes in the amount of air, the power of the boiler during the combustion process changes depending on the temperature of the coolant.
The electronic system displays various indicators to monitor the operating mode of the boiler. The boiler has an indicator of the minimum amount of fuel in the firebox and sends a signal to the owner about this. The design of the boiler provides the possibility of additional fuel loading without stopping the combustion process.
Equipment manufacturers produce universal combi boilers, which can burn fuel in two modes - with air supply either from below or from above. The cost of such boilers is naturally higher.
Automatic solid fuel boilers
Automatic solid fuel boilers are available for sale. It would be more correct to call them semi-automatic, since the boiler still requires certain actions from a person periodically, albeit not every day.
You can get acquainted with the design and operating principle of an automatic solid fuel boiler if you watch this video clip:
The fuel for an automatic boiler can be granulated coal with a fraction of 5 - 25 mm. or wood pellets - pellets, as well as pellets from other combustible materials - peat and waste of plant and animal origin.
The need to use only granular fuel for combustion in automatic boilers, causes certain difficulties for home owners. The cost of such fuel on the market is noticeably higher than conventional chopped wood or coal.
In automatic boilers, manufacturers often provide the possibility of replacing the burner for granular fuel with another burner - for gas or liquid fuel. Instead of a burner, grates can be installed. In this option, the boiler turns into a regular wood-burning boiler.
Granulated fuel is usually sold in bags. Fuel is easily and dust-free loaded into the boiler hopper. One loading of the bunker is enough for 3 - 10 days of boiler operation.
After ignition at the beginning of the heating season, combustion in an automatic boiler occurs continuously. The automatic boiler can operate in two modes:
- Active combustion mode, at which the boiler power can be in the range of 10 - 100% of the nominal.
- Combustion support mode, when the boiler power is selected to ensure the coolant temperature in the boiler circuit is about 55 degrees C. The automatic controller switches the boiler to support mode when there is no heat extraction from the heating circuit. This mode is necessary to protect the boiler from low-temperature corrosion (see below for more details), and also ensures that the boiler is always ready to resume active combustion.
During boiler operation it is necessary:
- Monitor the filling of the bunker and load fuel into the bunker once every 3 - 7 days.
- Remove ash from the removable ash drawer every 2 to 4 days.
- Once a week, clean the internal surfaces of the boiler from deposits with a special tool.
- Every year, before the start of the heating season, clean and check the serviceability of the boiler chimney.
How to choose the power of a solid fuel boiler
A solid fuel boiler must be selected so that its rated heating power corresponds to the heat losses of the heated object.
Selecting a boiler with a rated power that is too high results in the boiler most time operates in a mode of significant power limitation. And this, in turn, leads to a decrease in efficiency (increased fuel consumption), increased formation of deposits (soot, tar), accelerated corrosion of the boiler and chimney. The risk of overheating of the coolant in the boiler increases. The cost of boilers increases as power increases.
That's why you should not buy a boiler that has significantly higher power than heat loss at home.
True, when selecting a boiler with a large power reserve, the burning time of one load of fuel increases - there is more firewood in the firebox. But, this advantage can be realized profitably only in a heating system with a heat accumulator.
An accurate calculation of the heat losses of the house and the power of the heating boiler is sufficient difficult task, the solution of which is best left to specialist designers. Managers of a company that sells boilers will most likely advise you to choose a boiler with excess power - this is beneficial for them.
Approximately choose the boiler power for heating the house, guided by generally accepted values of specific power per 10 m 2 of heated area according to climatic zones:
- For the southern regions of Russia: 0.7 - 0.9 kW/10m2.
- For middle zone- 1.2 - 1.5 kW/10m 2.
- For northern regions - 1.5 - 2 kW/10m 2.
For example, for the Moscow region, in a house with a heated area of 150 m2, a boiler with a capacity of 150 m2 x 1.2 kW/10 m2 = 18 kW should be installed.
For a house built in compliance with modern energy saving requirements, the smaller of the specified values is used for calculations.
It should also be taken into account that the heat capacity of non-freezing liquids is 20% lower than that of water. When used as a coolant, the boiler power may drop by 10 - 15% of the nominal value.
Water heating system with natural circulation It is recommended to use coolant in houses with a heated area of no more than 100 m 2. In larger houses or in heating systems with heated floors, they are used forced circulation coolant with the installation of circulation pumps.
Protection of solid fuel boiler from overheating
In a solid fuel boiler, the burning fuel, and the boiler itself, have a fairly large mass. Therefore, the process of heat release in the boiler has great inertia. The combustion of fuel and heating of water in a solid fuel boiler cannot be stopped instantly by stopping the fuel supply, as is done in a gas boiler.
Solid fuel boilers, more than others, are prone to overheating of the coolant– boiling of water if heat extraction is lost, for example, if the circulation of water in the heating system suddenly stops, or more heat is released in the boiler than is consumed.
Boiling water in the boiler leads to an increase in temperature and pressure in the heating system with all serious consequences - destruction of heating system equipment, injury to people, damage to property.
Modern closed heating systems with a solid fuel boiler are especially prone to overheating, since they contain a relatively small volume of coolant.
Heating systems usually use polymer pipes, manifold control and distribution units, various taps, valves and other fittings. Most elements of the heating system are very sensitive to overheating of the coolant and pressure surges caused by boiling water in the system.
A solid fuel boiler in a heating system must have protection against overheating of the coolant.
To protect the solid fuel boiler from overheating In a closed heating system that is not connected to the atmosphere, two steps must be performed:
- Shut off the combustion air supply to the boiler furnace to reduce the intensity of fuel combustion.
- Provide coolant cooling at the outlet of the boiler and do not allow the water temperature to rise to a boil. Cooling must occur until the heat generation is reduced to a level at which boiling of water is no longer possible.
Let's look at how to protect the boiler from overheating, using the example of the heating circuit shown below.
Connection diagram for a solid fuel boiler to a closed heating system
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Scheme of a closed heating system with a solid fuel boiler. 1 - boiler safety group (safety valve, automatic air vent, pressure gauge); 2 — tank with a supply of water for cooling the coolant when the boiler overheats; 3 - float shut-off valve; 4 - thermal valve; 5 - connection group for expansion membrane tank; 6 - coolant circulation unit and boiler protection from low-temperature corrosion (with pump and three way valve); 7 - heat exchanger for protection against overheating. |
Boiler overheating protection works as follows. When the coolant temperature rises above 95 degrees, the thermostat on the boiler closes the air supply damper into the combustion chamber of the boiler.
Thermal valve pos. 4 opens the supply of cold water from the tank pos. 2 to the heat exchanger pos. 7. Cold water flowing through the heat exchanger cools the coolant at the outlet of the boiler, preventing boiling.
A supply of water in tank pos. 2 is necessary in case there is no water in the water supply, for example, during a power outage. Often a common storage tank is installed in the water supply system of a house. Then water for cooling the boiler is taken from this tank.
A heat exchanger to protect the boiler from overheating and cooling of the coolant, pos. 7, and a thermal valve, pos. 4, are usually built into the boiler body by boiler manufacturers. This has become standard equipment for boilers designed for closed heating systems.
Today, an autonomous heating system in a house is not something surprising and unique, but a completely normal state of affairs. Year after year, heating systems are improved and become better and better. Today, the culmination of progress is precisely solid fuel heating systems.
For your convenience, the article is divided into chapters:
What is important to know when installing a heating system
What do you need to know when installing a heating system? Most often, boiler users do not know what exactly they need and therefore it is very easy to succumb to the “wise” advice of neighbors, acquaintances and relatives about what and how to do. Nevertheless, the heating system is a complex and important mechanism that contains circuits for the coolant, and much, much more. Therefore, it is necessary to have at least basic knowledge so as not to reproach yourself later for the money saved and an inoperative or unreliable heating system.
- To begin with, even if your house is almost finished or you just want to change the boiler, think and analyze Is your home properly insulated? After all, if the house is poorly insulated, no heating system will help you. And it doesn’t matter whether the heating system is gas or solid fuel. So task number one: a well-insulated house.
- Find a good specialist. Ideally, this should be an authorized company. Yes, they will take more money, but they will give a guarantee for their work. Of course, maybe you will be lucky and come across a folk craftsman, but is it worth the risk? By the way, a businessman’s connections with all sorts of companies, such as gas companies or others, are not at all an indicator of quality. Discuss whether it is a single-circuit system or a double-circuit system.
- remember, that A heating system is not just elements assembled in a certain order, but a complex engineering network. In which all diameters, pressure levels and much more must be clearly thought out.
Types of heating systems based on fuel
Depending on the type of fuel, heating systems are divided into the following types:
- Liquid fuel heating systems(fuel oil, alcohol) - A very expensive pleasure today. But maximum autonomy. In addition, if, for example, a diesel generator is used in parallel, then electricity can also be generated. Although again - very expensive. Fuel oil is more practical, but is not used in private homes, although it serves well as a type of fuel for heating entire areas or cities.
- Gas heating systems. A common sight today. Gas boilers are quite reliable and unpretentious. Of course, the main disadvantage is the need for gas supply through a central supply.
- Since our site is dedicated to solid fuel boilers, we will talk separately about heating systems using solid fuel. What needs to be taken into account in this case is the different efficiency of boilers depending on the type of fuel. For example, briquettes can also be burned in wood boilers, but the efficiency will change significantly. on solid fuel and correlate this calculation with the fuel that you are going to use, because in some cases it happens that it is cheaper to heat with the same gas, if, of course, the gas is supplied to the house. Also be prepared for the fact that a solid fuel heating device will cost you more than any other system. But at the same time savings on fuel will range from 15 to 50% depending on the type of consumption, type of fuel and degree of insulation of the house.
Heating system with solid fuel boiler
How comfortable is the heating system to use? In addition to the fact that heating systems are not inferior in comfort of use to conventional, more popular systems, they are also much more economical. In a solid fuel heating system, the following elements are used:
- Boiler - heat generator
- - this element takes care of the uniform combustion of fuel, for its most efficient combustion. The storage tank has a very important function: even after fuel combustion, it releases accumulated heat into the system, which generally stabilizes the operation of the entire system. Depending on the type, it may contain a tank to meet the needs for large volumes of water, for example for taking a bath. Also, depending on the configuration, the tank may have an additional heating element - ten. During peak loads, it supports the system by helping to heat the water. There are also small electric boilers that are installed directly on the flow pipe, with the same purpose - to support the main boiler during peak loads and prevent the water from quickly cooling after the fuel burns out. After all, maintaining the temperature requires less energy than for initial heating.
- Thermostatic mixer— controls a stable temperature by mixing hot (already heated) and cold water.
In this article we will introduce the reader to the world of modern solid fuel heating systems. What types of solid fuel water boilers are there?
Is the use of this particular type of fuel economically justified? Does it have any serious flaws? We will try to answer all these questions.
The canonical diagram of the device, including a hob. As we will see later, this is far from the best design.
Boiler classification
It is clear that all solid fuel boilers for water heating are characterized by a number of common features. By definition, they use the heat of combustion of wood (optionally, its processed products), peat or coal. In addition, the coolant temperature at the boiler outlet does not exceed 100 degrees.
How do these devices differ from each other?
Material
We are talking about the material of both the boiler itself and its heat exchanger - the unit through which the coolant comes into contact with the firebox.
There are two main options:
- Steel boilers are on average somewhat cheaper and have much less weight. However, they are also characterized by a shorter service life. Steel is a metal that is afraid of corrosion; flames and very aggressive condensate quickly destroy it.
However: high-quality solid fuel heating boilers made in Russia, like imported ones, are made from heat-resistant grades of corrosion-resistant steel. In addition, the firebox is often additionally protected by a lining of refractory bricks.
- Cast iron is a material that is much less susceptible to corrosion. That is why it is used for the manufacture of grates and doors in furnaces; This is why cast iron boilers are, on average, much more durable than steel ones.
The price of a longer service life is a larger mass of products. As a rule, even boilers of modest (up to 16 kW) thermal power require mandatory installation exclusively on a permanent foundation.
Fuel
The most versatile are solid fuel water boilers that can operate on several types of fuel. Without any adaptation, you can, after cleaning the ash pan, throw coal into the firebox after firewood or peat briquettes after pellets.
However, devices focused on only one type of fuel tend to have higher efficiency. Their design is optimized for combustion with a very specific flame temperature and fuel humidity.
In addition to single-fuel boilers, boilers with two separate fireboxes and two heat exchangers are produced. They allow the combustion of different types of fuel, which require different design of the combustion zone. In fact, a solarium burner will quickly become unusable if it is placed among burning wood.
Efficiency
Efficiency different types boilers vary greatly. The factors that determine this parameter are the temperature of the combustion products at the outlet and the amount of solid waste. In both cases, less is more.
The minimum efficiency, often not even reaching 50%, is for the simplest hand-made devices. Yes, a box made of steel sheet with two doors and a coil inside will cost very little; however, to get the amount of heat you need, you will have to burn a LOT of wood.
Factory production of solid fuel boilers relies on accurate calculation of their shape and dimensions of the heat exchanger. Even in younger models, the temperature of combustion products usually does not exceed 120 degrees. Besides that large quantity heat is transferred to the coolant, which also means greater fire safety.
The so-called pyrolysis, or gas generator boilers, stand apart. How do they work?
- The device contains two fireboxes with heat exchangers in each of them. They communicate with each other and are placed one above the other.
- In the upper furnace in conditions of lack of oxygen and high temperature The firewood slowly smolders, gradually disintegrating into ash. There are no large coals left during normal operation of the boiler.
However, due to the lack of an oxidizer, the fuel does not burn completely: it releases a large number of pyrolysis gas consisting of CO (carbon monoxide) and volatile hydrocarbons.
- This gas is forced into the lower firebox, where it burns completely after oxygen-rich air is mixed with it.
Gas-generating solid fuel water heating boilers have a very high efficiency, reaching 95 percent for the best devices. However, they are 1.5-2 times more expensive than traditional designs and require the use of low-humidity fuel. In addition, younger models ONLY run on wood.
Autonomy
Devices of traditional design require constant human presence - the firebox must be loaded every 2-4 hours. The profession of a fireman was not born out of nowhere. It is this property that is the main disadvantage of solid fuel; This is partly why, if main gas is available, it is rare that a cottage owner will think about firewood or coal.
A pyrolysis boiler, however, due to the principle of its operation, causes the fuel not to burn, but to smolder. On one load the boiler can operate for up to 12 hours.
Relatively recently, the Lithuanian company Stropuva has established in-line production of so-called top-combustion boilers. They provide heating with even greater autonomy: during certification in 2003, the production model, after loading 50 kilograms of fuel, delivered about 6 kW of thermal power for about a day and a half.
How is this achieved? long time work?
- The volume of the firebox has been increased and can accommodate several tens or even hundreds of kilograms of fuel.
- There is no grate and ash pan.
- Only the top layer of loaded fuel burns. Air to maintain combustion (more precisely, smoldering) is supplied from above through a movable unit, which lowers under its own weight as the wood or coal burns.
- The ashes are carried away with the smoke.
- The fuel smoldering area is separated from the top of the chamber by a massive metal disk (slang name - staskoblin). Above it, air from outside is mixed with the products of incomplete combustion of fuel, and they burn with the release of residual heat.
As we can see, these devices are basically pyrolysis water-heating solid fuel boilers, but with serious design modifications. It is clear that here the price tag will not please the thrifty owner.
Boilers operating on pellets - pressed sawdust granules - stand apart. In them, the problem of autonomy is solved by the controlled supply of granules from the hopper.
The photo shows a boiler with a pellet hopper.
However: in addition to being expensive, these devices have another problem. Pellet production has not been established in our country; Not everywhere you can provide yourself with this type of fuel.
Automation
In classic boilers, all automation is limited to the simplest protection against overheating of the coolant. A mechanical thermostat uses a lever to pull a chain that closes the damper. The air flow rate decreases; the heat output of the boiler decreases.
There are much more possibilities in pyrolysis heaters:
- Mechanically or electrically controlled dampers here also allow you to regulate traction;
- Along with this, in devices with forced draft, their thermal power can be controlled by adjusting the speed of the exhaust fan.
In addition, it is possible to control not the coolant temperature, but the air temperature in the room.
Useful: inexpensive solid fuel heating boilers made in Russia, as a rule, are controlled by a primitive mechanical thermostat or generally only manually. You should not look for devices among the younger models that can independently maintain a comfortable temperature. However, it is precisely because of their simplicity of design that they are extremely fault-tolerant.
Advantages and disadvantages
Operating costs
At current Russian prices, purchased firewood is the second cheapest after mains gas. The difference between them is small - a few percent. It is clear that we are talking about the cost of generating one kilowatt-hour of thermal energy.
Coal is more expensive, but not much.
Several other factors speak in favor of firewood:
- Mains gas is not available everywhere, and liquefied heating is several times more expensive and is close in cost to electric heating.
- You can prepare firewood yourself, which will reduce costs to zero.
- Solid fuel heating will allow you to profitably dispose of most household waste. The rest is in the conditions country house will go into compost and fertilize the soil.
Ease of use
But in this area there are only disadvantages.
- Combustion products must be removed. Moreover, using a coaxial outlet - an air intake, as in gas boilers with a closed burner, it will not be possible to utilize furnace gases. A full chimney is needed.
This decoration on the roof is an invariable attribute of heating with solid fuel.
- Solid fuel boilers are available only in floor-standing versions. They are massive and large in size. In most cases, it is better for them to have a separate room.
- Fuel should be stored close to the boiler, and under a canopy. Compare this requirement with the convenience of connecting to gas or electricity.
- Adding fuel and removing combustion products are often required. Even in boilers long burning where there is no ash pan at all, you will still have to clean out the pan between fuel fills. In addition to being a rather dirty job, this means one more thing: you won’t be able to go away for a few days and leave the house warm.
Installation
All devices of the type we are discussing can be installed independently. No accounting or control of utilities is required.
However, a couple of rules must be followed.
- Massive boilers are mounted, as already mentioned, exclusively on their own foundation. It’s definitely not worth putting 300 - 500 kilograms of cast iron on a wooden floor.
In general, it is better to play it safe with lighter steel ones: for example, Belarusian-made solid fuel boilers KSV 12.5 with a modest power of 12.5 kW weigh 180 kg.
- The second instruction is related to fire safety. The boiler body and chimney become noticeably hot when fuel burns. It is recommended to place the boiler at a distance of at least half a meter from the nearest wall.
If the walls are made of flammable material, they are protected with a brick or a galvanized sheet with an asbestos gasket.
The chimney is separated from combustible ceiling structures or walls by a distance of at least 25 centimeters.
Conclusion
The video at the end of the article will tell you a lot of interesting things about what solid fuel boilers are like - Russian-made and imported from abroad. We hope that you will find answers there to any questions that you might still have.
Content
- Types of hot water solid fuel boilers
- Pros and cons of a solid fuel boiler
- Technical characteristics of TT boilers
For those living outside the city or just considering buying a country house, the heating problem is extremely acute. Main gas is absent in 34.5% settlements in Russia. There is also often no access to power grids when the village is new or when the house is built at a distance from power lines. Therefore, a solid fuel heating boiler is sometimes the only available option.
Let's try to figure out what hot water solid fuel boilers are, how they work and what they are. We will also consider their advantages and disadvantages, and the main specifications. We hope this material will help you decide which one is better to choose for heating your home.
Types of hot water TT boilers
A solid fuel boiler is a heating device that uses the energy of burning solid fuel. Most often it is wood or coal. However, some manufacturers produce models that run on pellets and fuel briquettes.
Based on the type of solid fuel used, boilers are divided into:
wood burning
This category includes conventional wood-burning boilers. Their disadvantage is that wood has low heat transfer and burns out quickly. Therefore, it is necessary to add firewood to the firebox every 2-4 hours.
coal
Coal boilers operate on brown or black coal, anthracite, and coke. The heat transfer of coal is 2 times greater than that of wood, and besides, coal is more compact. One bookmark is enough for 8-10 hours.
pellet
They work on special granules - pellets. They have a high efficiency of 85-95%. Their significant disadvantage is high price the devices themselves and the fuel for them.
universal
Can run on wood, coal or pellets to choose from. The efficiency of universal boilers is lower than that of those using one type of fuel. Manufacturers also produce two-furnace models. Each type of fuel has its own combustion chamber and its own heat exchanger.
Based on the material of the heat exchanger, they are divided into:
cast iron
The advantage of a cast iron heat exchanger is its high heat capacity and corrosion resistance. Such products will last 30% longer than their steel counterparts. The disadvantage of cast iron heat exchangers is their fragility and sensitivity to temperature changes. We also note that cast iron ones are 2-3 times heavier than steel ones, as a result of which even low-power models have to be installed on a concrete foundation.
steel
Boilers with a steel heat exchanger are 30-60% cheaper than their cast iron counterparts. The disadvantage of a steel heat exchanger is the formation of corrosion due to water condensate.
There are two methods of burning solid fuels: classical and pyrolysis. Depending on which method is used, all models are divided into two types:
classic
In classic boilers, the combustion process takes place naturally. They are characterized by simplicity of design and, as a consequence, low price. Their disadvantage is low efficiency (75-85 percent) due to incomplete combustion of fuel.
pyrolysis (or gas generator)
The peculiarity of these devices is that solid fuel and the gas it produces burn separately. This achieves greater efficiency compared to classical ones (about 85-92%). Such devices are much more economical and environmentally friendly than classic ones. about 1.5 times more expensive than traditional ones.
According to the loading method, solid fuel boilers are distinguished:
with manual loading
To maintain a constant heating temperature, it is necessary to manually add a new portion of solid fuel every 2-4 hours.
with automatic loading
The design of the heating system is complemented by bunkers for automatic fuel supply. Depending on the volume of the bunker and the amount of solid fuel in it, the battery life ranges from several tens of hours to one month.
Photo 2: Boiler with automatic fuel supply According to the degree of dependence on electricity, they are divided into:
non-volatile
In volatile boilers, air is forced into the combustion chamber by a mechanical thermosyphon.
volatile
Volatile boilers use an electric fan to force air into the combustion chamber. This process is controlled by an electronic unit that requires connection to the electrical network.
We have figured out the classification, now let's look at the design and operating principle of a TT heating boiler. It consists of the following components and assemblies:
Combustion chamber
The fuel combustion process takes place in this compartment of the boiler;
Heat exchanger
This device is made of cast iron or steel. It transfers the energy of burning fuel to the coolant;
Cleaning hatch
There is a special hole in the ash pan. Ash and combustion waste are removed through it;
Grate
A metal grate between the combustion chamber and the ash pan on which the combustion process occurs. Ash falls through holes in the grate into the ash pan, from where it is then removed manually;
Thermostat
A mechanical or automatic device that regulates the intensity of combustion, and therefore the temperature of the coolant;
Photo 3: Construction of a wood-fired hot water boiler The process of operating a boiler with a water heating circuit is very simple. Solid fuel is placed through the loading door into the combustion chamber. During the combustion process, the heat exchanger heats up and transfers energy to a coolant, such as water. The coolant circulates through the heating system to warm the room. Ash and other combustion waste accumulate in the ash pan.
Return to contentsPros and cons of a solid fuel boiler
Any heating device has its advantages and disadvantages. Let's weigh the pros and cons of TT boilers. The advantages of solid fuel heating devices include:
fuel availability
Wood and coal rank first among the most common types of fuel in Russia and the post-Soviet space. Forests cover 46.5% of the territory of our country.
low cost
For many of us, the cost of a product is critical. The cost of solid fuel models is significantly lower than gas or electric ones.
For example: A solid fuel boiler Dakon with a power of 24 kW costs 52,000 rubles, and a gas boiler of the same power costs 97,000 rubles.
no dependence on the power grid
There is no electricity supply in many villages and country houses. Therefore, this quality of solid fuel boilers comes in handy in this case.
long service life
With appropriate care and maintenance, timely cleaning and careful operation, the service life of solid fuel boilers reaches 30 years.
Photo 4: Solid fuel wood boiler in operation We've sorted out the advantages, now let's talk about the disadvantages:
the need for constant monitoring
The fuel in the firebox burns out quickly. It is necessary to reload every 2-4 hours to maintain the required temperature in the room.
complex and time-consuming care
Maintaining a solid fuel boiler is not an easy task. It is necessary to promptly remove ash from the ash pan, and also clean the combustion chamber from soot. It is better to entrust complex work such as cleaning from scale, rust and tar deposits to professionals.
low efficiency of solid fuel combustion
Compared to fuels such as gas and diesel, solid fuels have low combustion efficiency. The combustion process leaves waste in the form of ash, while gas and diesel leave no waste.
need for fuel storage
Firewood and coal have quite impressive dimensions. It is necessary to equip a separate room for storing their supplies.
inertia of the combustion process
The main feature of solid fuel boilers is their high inertia. The combustion process cannot be quickly interrupted. The boiler will continue to heat the water in the heating system even if it is already overheated. One way to solve this problem is to install a heat accumulator (buffer tank).
