Pellet boiler - source economical heat, located either as a free-standing device or having a built-in structure, capable of heating both a separate room and the whole house. To heat adjacent rooms from one boiler, a ventilation system of air ducts or simple ventilation holes between rooms is used, and the temperature difference between rooms is very small and does not negatively affect the comfortable stay of people.
Water, gas or electric heating have reached the peak of their efficiency capabilities, but they are not always available, especially in areas remote from gas mains populated areas or cottage villages, but there’s nothing to say about detached houses...
Assessing economic and practical developments, consumers are increasingly choosing pellet boilers, preferring them to other heating systems.
Operating principle of a pellet boiler
The main components of pellet boilers are the combustion chamber, burner, pellet hopper and automation.
Pellets, a type of solid fuel, flow through the first auger into the pre-furnace, and from the burner pre-furnace to the nozzle via the internal auger.
After pellet granules hit the nozzle, the automation produces automatic ignition, accompanied by further complete combustion of the supplied pellets.
For reference: pellets (English) Pellet's) are fuel wood pellets, shaped like small cylinders of sawdust, formed under high pressure. Chemical fixatives and other harmful substances are completely absent.
The calorific value of 1 kg of pellets is equal to 5 kW/hour of absolutely environmentally friendly heat. And this is the same as half a liter of diesel fuel. At the same time, pellets burn more completely and efficiently than firewood; they are denser and occupy less space Moreover, pellets are not prone to accidental spontaneous combustion. CO 2 emissions are significantly lower than those of coal, and the greenhouse effect is consequently reduced.
Ash cleaning is done relatively infrequently - once a week or less, and the chimney should be serviced once a year.
A few simple but important rules, thanks to which, after installation, the pellet boiler will not require additional measures and alterations:
- It is better that the pellet boiler is installed in a separate room (annex, basement, etc.);
- the floor in the boiler room is concrete or ceramic tiles;
- the location of the boiler should ensure maintenance, cleaning and repair without difficulty, and from the front wall of the boiler to opposite wall– at least one meter;
- the temperature in the room where the pellet boiler is installed is at least +10˚C, the humidity is normal.
- in accordance with the boiler power it is necessary to ensure supply and exhaust ventilation in the boiler room.
Why is an automatic pellet boiler becoming popular?
High efficiency
The efficiency of burning wood in a clean and dry form in an open flame is approximately 35%, but pellets of the same mass, burning under exactly the same conditions, produce up to 85% efficiency. And some pellet stoves have an additional water heating circuit for distributing heated water throughout the rooms, which increases their efficiency even up to 93% value.
- Efficiency electrical energy – 97,0%;
- Natural gas efficiency – 87.1%;
- The efficiency of wood pellets is 86-93%.
Automation and convenience
The pellet stock is stored in a special bunker connected to the combustion chamber. The supply of pellets to the boiler is fully automated, taking into account the weekly program set by the consumer himself! In addition to the obvious fuel savings, there is also a less noticeable advantage - convenience, since a couple of hours before the company or family arrives at the dacha, the boiler itself will turn on the ignition, set an even flame and welcome you with cozy warmth in the house.
According to your program, say at midnight, the pellet boiler will smoothly turn off the heating so that you can sleep soundly at a lower temperature, and at morning time will turn on again so that guests and hosts can wake up not in a cold, but in a warm room. Automation can be controlled using display buttons or using a convenient remote control.
Pellet boiler hopper
A medium-sized bunker (200-300 liters) is designed for up to 3 days of continuous operation of the boiler. The consumption of pellets for a boiler of average power (25 kW) is less than 5 kg per day, compare with firewood.
In addition to the internal bunker, it is possible to construct a more capacious external one, which is limited only by desire and free storage space. Most often, this bunker becomes quite large plastic barrel or an even more spacious design made of metal corners, covered with sheet plywood.
A large plastic bag (big bag), in which pellets are supplied, can also, if carefully unloaded, become a kind of bunker in which from 500 to 800 kg of pellets are stored. Since the external bunker is loaded outside the room, there is no need to carry pellets around the house.
Exploitation
The combustion is monitored by a control system; the burner for a pellet boiler is loaded with no more than a handful of pellets at a time, so overheating of the system is impossible. It will take 5, maximum 10 minutes for the next portion of fuel to burn out after pressing the switch off button of the pellet boiler! After which the combustion stops completely.
Environmental Safety
In pellet boilers, the air supply circuit for combustion is completely separated from the air heating circuit, which saves everyone from the harmful effect of “burning out” oxygen, so the room is comfortable. Many users provide air intake from the basement, which additionally ventilates and dries the basement. Possibility of hitting carbon monoxide into the room is completely excluded.
What else should be emphasized when it comes to the advantages of pellet boilers:
- a low-noise and low-power fan ensures uniform circulation of heated air;
- total electricity consumption (fan + automation) – no more than 60 watts;
- since the fuel burns much better than ordinary dry wood, the combustion products are truly minimal;
- if compared with a traditional stove, even of the highest quality, burnt pellets will leave half as much soot and ash;
- the heating system works to heat the air, not the body, which makes it safe for children or animals;
- spacious bunker – self-sufficiency of the pellet stove with fuel.
- operation control - thermostat, timer or intelligent control systems - this is a safe continuous operation of the boiler.
For reference: 1 ton of pellets in volume will be about one and a half to two cubic meters, which will make it possible to provide yourself with a large supply of fuel (2-4 tons of pellets = 4-6 cubic meters of volume, which is not so much).
In recent years, several convenient systems feeding pellets into the boiler (pneumatic, screw and others), so the buyer has a choice.
Disadvantages of a pellet boiler
But let’s not idealize the situation, not everything is so simple, there is, of course, a small fly in the ointment.
Although pellets are made from wood waste, their cost per unit of heat generated still exceeds the cost of conventional firewood. Therefore, you have to pay extra for convenience.
Storing pellets requires the creation certain conditions, here simple canopy you can't get by. Due to water or high humidity, pellets swell and fall apart, and the augers can become clogged. Therefore, they should be stored in a dry place, such as a basement.
Cost of the set additional equipment together with a medium-power pellet boiler, which includes a voltage stabilizer and a gas generator, it will cost about 250 thousand rubles. Which, you must agree, is quite expensive.
Pellet consumption in winter is approximately 1 ton per month. Once you find out the cost of pellets in your region, you can easily calculate what winter in a private home will cost you. The price is comparable to electric heating and is still more expensive than natural gas. On the other hand, constantly rising energy tariffs suggest that the future lies with pellet boilers.
Video review - 15 kW pellet boiler.
Results and conclusions
The successful operation of solid fuel boilers, including pellet boilers, which began in 1979, has provided excellent statistical data. Usage advanced technologies production of equipment and raw materials has led to significant improvements in the quality, safety and efficiency of pellet boilers, not only comparable, but in many ways superior to other heating technologies.
IN modern society houses are increasingly being built with autonomous systems heating, therefore the demand for wood fuel is steadily growing, since it is a natural and renewable source of thermal energy. Prices for pellets, due to the availability of raw materials, are quite stable, which cannot be said about other energy sources: so a pellet boiler becomes both an economically and environmentally justified solution.
The price of a pellet boiler depends on the heating area, but, as calculations show, the larger the area, the lower the payback period. For small areas this period is three to four years, and for large ones - from one to two years.
For the first time, the production of wood pellets was organized in the USA. This happened during the energy crisis of the 1970s, when Western countries had to look for an alternative to petroleum fuel, since Arab countries their supplies have been reduced. The first domestic pellet heat generator appeared in the middle of the next decade. And in the 1990s, such boilers began to be actively used in European countries and very quickly took a strong position in the market.
This was facilitated by both global political factors (the need to reduce the consumption of fossil fuels, ecological problems etc.), and purely economic feasibility: pellets are significantly cheaper than liquid fuel, and the price change for them is more predictable than for petroleum products.
Among the “pellet boilers” there are “omnivorous” models, but for most boilers the standard use of high quality wood pellets is provided
What you need to know about pellets
Fuel pellets are granules obtained by pressing. The raw material for them can be not only wood, but also agricultural waste, biomass from energy plantations, etc. However, most household heat generators are designed to use wood pellets of a certain standard, which guarantees efficient operation of boilers with a minimum amount of maintenance and the amount of harmful emissions in environment, not exceeding the maximum permissible.
Since 2010, in the countries of the European Union, the production of wood pellets is regulated by the EN 14961-2 standard. On its basis, the German Pellet Institute (DPI) developed the ENplus standards, the certificate of conformity of which is considered by manufacturers and users of household pellet boilers as a guarantee of high fuel quality.
According to the standards, wood fuel pellets are divided into classes A1, A2 and B. Granules of the first two of them are used in heating systems individual houses. Pellets of the third class are considered as industrial, i.e. intended for industrial boiler houses. The highest grade of pellet fuel is L1. It is recommended for heat generators of low and medium power. Such granules must have a low ash content (no more than 0.7%), an increased melting point of ash (1200 ° C) and meet a number of other requirements ( bulk density- not less than 600 kg/m3, abrasion - not more than 1%, mechanical strength - not less than 97.5%, pellet length - from 3.15 to 40 mm, calorific value - from 16.5 to 19 MJ/kg; the content of chlorine, sulfur, nitrogen, and a number of metals is limited). The diameter of class A1 pellets is 6 or 8 mm.
The quality of granules directly depends on the raw materials from which they are produced. To produce class A1 pellets, it is allowed to use industrial wood (logs) and chemically untreated waste from the wood processing industry without adding bark. Class A2 pellets are produced from a wider range of raw materials; in particular, they can be used from whole trees without a root system. Therefore, they are characterized by higher ash content - up to 1.5%.
There is no domestic standard for pellet fuel yet. Since Russian manufacturers focus on foreign consumers (the bulk of their products are exported), they strive to comply with European standards. But when buying fuel for a boiler, you should not rely on the name “Europellettes” or the “white” color of the pellets, but on a certificate with confirmed product characteristics. Requirements for granules are indicated in the data sheet of your installation or its operating manual.
Depending on the ability to operate on one or more types of fuel, pellet boilers are divided into specialized and universal
As an example, we give the characteristics of the recommended fuel for domestic ZOTA Pellet boilers: pellet diameter - 8 mm, length - 15-35 mm, ash content - no more than 0.7, humidity - no more than 10%, bulk density - no less than 620 kg/m3 , sawdust content - no more than 4%, calorific value - no less than 4.8 kWh/kg.
It is not uncommon for boiler manufacturers to allow the combustion of pellets of varying quality with appropriate changes in settings and maintenance intervals. If necessary, you can select a boiler to operate on high-ash fuel - industrial and agropellets, bulk waste from woodworking and agricultural production.
With torch or retort
The combustion of pellets is organized using burners or in the traditional way for solid fuel boilers - on grates. There are two main types of pellet burners - torch and retort. The first of them are similar in principle of operation and appearance to gas and liquid fuel fan burners. They are compact and are usually used on universal boilers, the design of which allows for the possibility of switching from one type of fuel to another. Wherein alternative option There can be not only firewood, briquettes and their other solid “counterparts”, but also diesel fuel or liquefied gas.
Due to this versatility, it is possible, in turn, to convert a conventional boiler unit, designed for the installation of a mounted fan burner, to pellets; you only need to remove the ash from the firebox in time. The fire tube of a flare pellet burner serves as a fuel combustion chamber. The granules are burned in it on a nested grate (as an option) with forced submission required amount of air. The resulting combustion products are blown into the boiler furnace. In addition to the fan, some flare burners are equipped with their own device for feeding pellets into the combustion zone.
But for household heat generators, a feeder from a supply hopper is more often used: controlled by a burner controller, it pours through a flexible pipe required quantity pellets that fall directly onto the grate of the burner pipe. The supply of granules by the feeder is regulated automatically according to the need for thermal energy, and combustion air - in accordance with the conditions for complete combustion of fuel.
The combustion control circuit uses one or another set of sensors, including a draft protection sensor, a thermostat to protect the fuel supply system from backfire, a photoresistor that monitors the presence of flame, and others. To fine-tune the operation of the burner, a so-called lambda probe is used. By detecting the amount of residual oxygen in the flue gases, it provides the burner or boiler control unit with information on how best to regulate the air supply.
Pellet boilers require electrical power, which is necessary to supply pellets, combustion air, and operation of automation. Reliable power supply is especially important for specialized models (universal ones, as a rule, can be operated manually, for example, with wood). It is advisable to provide a source for them uninterruptible power supply.
The automation of a “smart” pellet burner can have many functions, including controlling elements of the heating system (circulation pump, boiler, mixing valve underfloor heating and etc.). A retort burner is a bowl with air channels onto which pellets are poured from above or pushed out by a screw. Fuel combustion occurs in the internal space of the boiler (this is called volumetric combustion). On average, boilers with retort burners have a slightly higher efficiency than with flare combustion, because It is possible to organize combustion in them more accurately - with separation of the supplied air (primary-secondary), etc. However, when comparing “advanced” boilers of both types, this difference is not very noticeable.
In addition, retort burners are easier to “fit” into the boiler firebox, i.e. the combustion chamber can be more compact (to one degree or another, this is also allowed by certain models of flare burners - with a fire tube open at the top). Therefore, despite the more bulky design, it is retort burners that are usually equipped with specialized pellet boilers. They are also available in a mounted version - for universal heat generators.
Pellet burners can be ignited manually or automatically. In the second case, electric heaters are used - direct contact or acting on the pellets with hot air. During periods when the boiler is turned on, but there is no need for heat, the burner with manual ignition is switched to standby mode maintaining minimal combustion (similar to an igniter gas boiler). With full automation of the pellet installation, there is no such need.
Deciding which boiler will heat Vacation home, you need to take into account not only the costs of purchasing and installing equipment, but also future operating costs - fuel and service. On average, a pellet boiler is more expensive than a diesel boiler, but the pellets themselves are cheaper than diesel fuel, so the “overpayment” will sooner or later - depending on fuel consumption - pay off.
Efficiency issues
Efficient combustion is also achieved by burning pellets on grates in the furnaces of specialized boilers. In the most advanced “pellet stoves”, pyrolysis combustion of fuel is also implemented: the wood of the granules that fall on the grate is subjected to thermal decomposition with the formation of flammable gases, which are then burned in the combustion chamber. And only then the combustion products enter the heat exchanger. This allows you to obtain an efficiency of 95% or more (the efficiency of pellet heat generators without pyrolysis usually does not exceed 90-92%).
The efficiency of the boiler depends not only on the burner, but also on the ability of the installation to absorb combustion heat and transfer energy to the heating system. Heat exchangers of specialized pellet boilers are often made in the form of a bundle of vertical smoke tubes that penetrate the volume of the water jacket. To improve heat transfer, spiral turbulators are built into the pipes. In high-tech models they are equipped automatic drive, with the help of which ash particles lingering in the heat exchanger are shaken off from flue gases. Under the influence of gravity, the ash falls into the compartment below.
You can reduce pellet consumption by using solar collectors. The automation of many pellet boilers is equipped with the necessary functions for this.
For example, some models are also equipped with a device for automatically cleaning the grate (it folds down). If the boiler is designed to burn low-ash pellets of standard A1, then its creators limit themselves to manually removing ash from the collection tank. But in boilers that allow the use of both pellets and wood chips, a screw conveyor is provided that automatically moves all the ash into a special removable container.
When it is filled, it is very easy for the user to transport the ash to Right place: The container is equipped with wheels and a handle, like a shopping cart. By the way, contrary to popular assertions, foreign experts do not recommend considering pellet ash as a fertilizer for plants.
For horizontal boilers, leading manufacturers use other methods for automatically cleaning the heat exchanger. For example, some models designed with a torch burner and a heat-pipe-smoke structure (a horizontal firebox with a bundle of smoke tubes placed above it) are equipped with a compressor for periodically purging the heat exchanger with air, which is done automatically - every 24 hours of burner operation.
The air in the combustion chamber of an automatic pellet boiler with a grate-type firebox is supplied by a fan, which is installed at the outlet of the heat generator, in front of the chimney. Smooth control of the fan rotation speed allows you to adjust the air flow in accordance with the need to burn a particular amount of pellets.
Boiler power
Fuel supply to a pellet boiler is organized in different ways. Installations with stationary built-in retort burners are often equipped with a 300-500 liter hopper located on the side or rear side, which is connected to the boiler by a rigid screw conveyor.
When using a mounted burner, an attached hopper is used - fuel is taken from it by a feeder in the form of a pipe with an auger inside. One end of the pipe is immersed in a hopper. The granules rise to the highest point and are discharged through a flexible hose to the burner. The feeder drive is located on top of the pipe and is controlled by the automatic burner or boiler. As a rule, tubular feeders for domestic boilers are equipped with a screw in the form of a flexible spiral.
Typically, attached pellet hoppers come in the same design as the boiler itself. This set looks aesthetically pleasing. And the absence of a rigid connection between the modules makes it possible to arrange them in a way that is convenient in each specific case. In addition to rigid and flexible screw conveyors, vacuum systems are used to supply pellets: the pellets move along a flexible pipe under the influence of vacuum created by a fan.
Some models are equipped with a built-in intermediate hopper (its capacity depends on the boiler power) with an integrated vacuum pump. Pellets are sent to it directly from the storage facility, while the length of the line to the boiler can be 30 m. To supply pellets from a remote (up to 10-15 m) bunker, spiral conveyors are also used, the advantage of which, like vacuum ones, is flexibility. As for a feeder with a rigid screw, its length should not be long so that the granules do not grind. The pellets can be supplied to the burner using a flexible auger from a storage facility without an intermediate hopper.
In the boiler room shown in the diagram, the supply of pellets from the storage is carried out using a pneumatic (vacuum) system. Equipment manufacturer Buderus (Germany) allows such transportation of granular fuel over a distance of about 25 m with elevations of 5 m or more. In this case, the bunker with pellets can be located both inside the house and outside - on garden plot or underground. The accumulator tank and compact pump-hydraulic groups ensure coordinated operation of the “pelletizer” with consumers and other heat sources.
In reserve
Storage of pellets for the boiler can be organized in a separate room of the house adjacent to the boiler room, as well as in a special tank - a silo. This could be a plastic or concrete bunker buried in personal plot, as well as a voluminous metal or plastic tank, which is placed directly in the boiler room. A convenient solution is easily installed flexible silos, which are textile containers (essentially bags) attached to frames.
Silos are combined with a screw or pneumatic conveyor. They are also filled in automatically. True, this is only possible where the granules are delivered to the user in special tank trucks equipped with a loading fan.
Flexible fabric silos - modern solution for storing pellets. They are easy to deliver, install, and fit into the volume of the room.
Despite the significant volumes of pellet production in Russia, the infrastructure for delivering this fuel to users similar to the European one in our country is not yet available. On the retail market, pellets are sold in bags with a capacity of 20 to 1000 kg. Buying them in large containers (“big bags”) is more profitable, but moving such packages is more difficult. Therefore, owners of pellet boilers often purchase pellets in 25-30 kg bags and pour them into the operational bunker manually, without arranging an automated storage facility.
During most of the heating season, one load of a 300-kilogram container is enough to operate a boiler with a power of 20-30 kW for several days. By the way, this method of fuel supply to small heat generators is also used by foreign users. For example, when pellets have to be stored in an insufficiently dry room (the packaging of the pellets is polyethylene).
"Smart" boiler
All elements of a pellet installation - boiler, burner, fuel storage and supply systems - must form a single complex, the coordinated operation of the elements of which is ensured by automation. The carrier of the “intelligence” of the boiler room can be the automation of the burner device, the boiler itself, or an external control unit.
Among pellet boilers, there are installations of various configurations and different levels of complexity. The use of a high-tech “pelletizer” is an opportunity to implement all control and regulation functions modern systems heating, right down to dispatching and changing settings using a smartphone or tablet computer. However, even a relatively simple pellet boiler must be “smart”. When controlling the combustion processes of granular fuel, one cannot do without electronics, which often simultaneously perform the duties of a controller of a heating system, including a multi-circuit system that includes other heat sources.
|
Konstantin
2015-08-15 08:47:10
Great article. Thank you - I was very helpful in selecting a business for producing pellets according to European standards. [Answer] [Reply with quote][Cancel reply] Pages: |
Pellet boiler - heating equipment that runs on pellets - a special type solid fuel. Pellets are granules produced by pressing waste from the wood processing industry.
The principle of operation of boilers and their internal structure
There are three types of devices:
- specialized equipment operating only on pellets;
- boilers that can operate on pellets only for a limited time, as with backup fuel;
- universal equipment that works with any type of solid fuel.
The pellet boiler structure includes three key element: the boiler itself with a burner, a pellet feeding mechanism, a fuel storage container. The equipment works like this: granules are sent from the container to the firebox and burn there; Then the heat is heated by the thermal carrier, which transfers energy into the room.
Thanks to design features firebox, the device is capable of delivering up to 96% efficiency. The heat exchanger can be steel (there is a risk of corrosion) or cast iron (sensitive to water hammer). The equipment is equipped with automatic equipment that controls fuel filling and monitors the set temperature. The power of household appliances ranges from 10 to 100 kilowatts, while industrial pellet boilers can be very powerful - up to 1500 kilowatts.
The boiler is easy to maintain. Depending on the intensity of operation and the volume of the bunker, new granules are supplied every 3-15 days. You also need to periodically clean the channels and throw away the ash accumulated in the tank.
Advantages of a pellet boiler
Among the most obvious advantages are the following:
- Rational fuel consumption. The granules burn so that there is no waste left.
- Relatively low cost of fuel compared to coal or firewood.
- Reasonable prices for pellet boilers. Gas and electric equipment are more expensive.
- The operation and maintenance of such equipment is not difficult.
- Environmental friendliness of the equipment.
Boiler selection criteria
To decide which pellet boiler to choose, you need to take a closer look at individual characteristics equipment. There are a number of parameters that have a direct impact on the efficiency of the device.
Burner type
Two types of burners are common: retort and stoker. The former are adapted to medium-quality granules and do not require frequent cleaning. Stoker burners need to be cleaned regularly and require high quality, low ash fuel.
Degree of automation
Pellet devices are equipped with automation equipment to varying degrees. Particularly interesting is the function of informing the homeowner about events in the heating system via SMS. Moreover, you can not only receive messages, but also remotely regulate the operation of the system by sending SMS.
Type of auger (feeder)
The system can have a flexible or rigid auger. A rigid auger is structurally simple and inexpensive. However, this element has disadvantages. Firstly, if the length cannot exceed a couple of meters, and secondly, due to the rigid connection to the burner, the position of the auger cannot be changed. As a result, the surrounding space cannot be used rationally. The problem can be solved using another auger on an electric motor.
The flexible auger can be installed at a greater distance - up to 12 meters. Also, the supply line can be any geometric shape. The main disadvantage of such a system is the complex screw fastening.
Heat exchanger device
There are many options for heat exchangers:
- made vertically or horizontally;
- tubular or flat;
- with different options for moves and turns;
- with and without devices for swirling gases.
The best option is a vertical type heat exchanger with a swirler and two or three passes. The advantage of this design is the ability to reduce the temperature of the flue gases, due to which most of the heat does not go into the chimney, but warms the room. Also, the vertical device does not contribute to the accumulation of ash inside the equipment.
When purchasing a boiler, you should ask the seller whether there are spare parts for it in stock or how quickly they can be delivered to the store if necessary. Servicing of the device should only be performed by certified personnel.
Making a boiler
Below are step-by-step instructions on how to build a pellet boiler yourself. Steel pipes or sheets with a thickness of 3 to 5 millimeters can be used as structural materials. You also need a working tool - an angle grinder and a welding machine. If you do not have welding skills, you can seek help from an appropriate specialist.
The workflow consists of several stages:
Assembly work
The easiest way is to create a horizontal type boiler. The system is based on a heat exchanger rectangular shape from square pipes. This cross-section allows you to create high-quality butt seams.
We start with the blank. Cut the pipe into pieces of the required length. Let's do round holes for pipes in the profile for vertical stand. We cut holes in the front pipes for drainage and pipes. There will be two drainage systems: one for cold water- below, the second - at the top - for warm water.
To make holes we use a gas or electric welding cutter. We process the holes with a grinder.
After we are done with the holes, we weld the back and front parts of the device together. The seams must be of very high quality, so we place the pipes and racks on a flat surface for convenient work.
We weld the side pipes, as well as round pipes to the heat exchanger. It must be installed in a firebox made of refractory bricks. We fix the square profile by welding. Assembly work has been completed.
Pellet heating boilers must be checked for leaks. To do this we take the following steps:
- place the structure in a vertical position;
- close the bottom hole;
- pour water into the container through the hole at the top.
If there are no leaks, you can begin installation work.
Note! If there are leaks, even minor ones, it is necessary to re-install welding work. Leaks are not allowed.
Boiler installation
Begin installation work from inserting the heat exchanger into a ready-made housing. It is worth dwelling on this element of the system in more detail. The body must be made of fireclay bricks concrete foundation. Brick laying is done using technology that is used to create kitchen stoves. It is important that the size of the housing allows for at least a centimeter distance between the heat exchanger and the walls from the inside.
After joining all the elements, we definitely check the quality welds. If everything is in order, we check the device for functionality.
Important! Under no circumstances should the boiler be placed in rooms where there are flammable or explosive substances, for example, gas cylinders.
Ways to increase efficiency
Fuel boilers suffer from one thing common disadvantage- they lose thermal energy escaping along with combustion products through the chimney. To avoid heat loss, you can use special heating panels, behind which the pipes are hidden. Due to its design, the heating shield retains heat that would otherwise go into the chimney.
Advice! To increase the coefficient useful action you can put the circulation pump directly in heating system, as well as additional heat exchangers.
Connecting to networks
The piping of a pellet boiler includes the following list of installation works:
- pumping circuits;
- fuses;
- expansion tank;
- shut-off valves.
You will also need to connect the boiler with the return and supply circuits, fill the circuit with coolant, carry out pressure testing and test the equipment.
The piping must be done very well, since defective work can lead to disruption of the functionality of the equipment. This can not only damage the boiler, but also pose a threat to the safety of the residents of the house. According to safety rules, when tying, it is permissible to use only fire-resistant metal pipes. The use of polypropylene is extremely undesirable, and technically impractical, since the coolant will have a temperature higher than this material can withstand.
The boiler is connected to the networks by sequentially performing the following steps:
- install the boiler;
- connect the burner;
- we install a pellet bunker;
- connect the conveyor (auger);
- We connect automation.
- we install safety groups consisting of an automatic air vent, a pressure gauge and a relief valve;
- install a sensor for the thermal valve;
- we install the chimney;
- we install devices for return flow: a pair of taps for supply and return, a thermal head and a circulation pump.
- We supplement the system with an uninterruptible power supply (if necessary).
The use of reverse flow makes it possible to control the heating rate of the coolant before it enters the heating system. The coolant will be contained only in a small circulation circle until the return temperature rises to a certain level. When temperature regime reaches the required value, cold coolant will be supplied through the thermal head, and hot coolant will circulate through the main circle.
Note! The boiler should not operate with cold coolant. If its temperature is below 55 degrees, condensation begins to form, which leads to increased accumulation of soot in the chimney and heat exchanger.
- It is recommended to equip the chimney for a pellet boiler with a condensate drain. Best material for drainage - stainless steel. General rule- the higher the outlet height, the better. It is also advisable to provide automatic chimney cleaning.
- Pellets must be stored in a specially adapted room with high-quality waterproofing. Pellets must be dry.
- An additional storage tank will save up to 30% of fuel, as well as prevent overheating and increase the efficiency of the boiler.
Assembly and installation of a pellet boiler requires certain skills and technical knowledge. Moreover, if everything is done correctly, the home owner will have at his disposal a very practical and efficient heating system at a relatively low cost.
Even in the hottest summer, a good owner should remember this. That the cold will come. It is for this reason that the issue of proper home heating remains relevant. Everyone wants their home to become warm and cozy, but there is no desire to overpay. The problem is easy to solve if you are able to install a gas heating device. But what to do if you don’t have such a benefit as gas, and electricity seems too expensive? This is where pellet boilers come to the rescue and are becoming very popular.
A pellet boiler is equipment that runs on a special type of solid fuel - pellets. Pellets are granules that are produced by pressing waste obtained from wood processing. The device is designed to provide the room with hot water supply. Models are produced that have different powers from 15 kW to 100 kW.
There are 3 options for this equipment:
- The first is intended for organizing work exclusively on pellets;
- The second provides the opportunity to use firewood or briquettes, but only as a reserve, since the work will last no more than 2-3 hours;
- The third is a combined one and is capable of working not only on pellets, but also on wood and coal, since the design includes several combustion chambers.
The boilers are a structure made of sheet steel. It includes several mechanisms at once, for example, a boiler with special pellet burners, a conveyor that will supply pellets to the combustion chamber and a bunker that stores fuel.
The work goes like this:
- Pellets, which are loaded into the tank using an auger, are sent to the firebox. There is combustion going on there.
- The heat generated during combustion warms up the coolant. He, in turn, distributes this throughout the room, which is heated.
Basically, all devices are equipped with automatic control; it regulates the fuel and maintains the temperature that was set by the coolant. Operation is very simple. The granules are placed in the boiler once for 3 to 14 days. It depends on the volume of the container. In addition, the boiler needs regular cleaning of the combustion channels and cleaning of the ash drawer. The service life of such an installation varies from 10 to 50 years, depending on the class.
Why pellet boilers are better than others
Those who have already purchased and used such a boiler highlight a large number of its positive aspects during operation.
Among the main advantages are the following:
- Economical fuel consumption. Since pressed wood burns without residue, the consumption is not high. It is difficult to say the exact indicator, since it depends on the composition and quality of the material. But if we take the average, then pellets will cost several times less than regular firewood.
- Independence from electricity. Most of the boilers on the market depend on the availability of electricity, especially since modern models include electrical appliances.
- Economical. The cost of such equipment is less than analogues running on gas or electricity. In addition, fuel is also cheaper than coal, gas or firewood.
- Easy to use.
In addition to these advantages, we can also say that their work is environmentally friendly and does not affect the environment. The choice of fuel boilers is gradually becoming a thing of the past. A boiler room, the operating principle of which is based on pellets, is a new word in modern home savings. This solution allows you to choose a solid fuel boiler using granular fuel, that is, pellets, and not worry about everyday issues.
The best automatic boilers can help you choose a video course. For example, the “Elephant” pellet boiler, which has improved equipment and runs on pellets, will not leave you indifferent; all its advantages can also be learned from video reviews.
Pellet auger - what is it?
These boilers can be equipped with rigid or flexible screws. Rigid ones have a simple design and reasonable price. It is capable of supplying fuel to the combustion compartment without failure and has a simple but reliable fastening, which guarantees long-term performance of the parts. Speaking about the disadvantages of the rigid variety, we can say that the main one is their limited length. It does not exceed 2 meters, otherwise the device may grind sawdust. In addition, the location of the hopper cannot be changed, since it is firmly attached to the burner. The space in this option is not used rationally.
In order to solve this problem, many resort to installing an additional auger, which will need to be connected by pairing electric motors.
A system that prevents backfire may involve the use of a fire extinguisher or a second air chamber, which adds significant complexity to the overall design.
The flexible screw does not have all these shortcomings. It can allow you to install a hopper with any parameters, and the distance between them can be up to 12 m. Despite the complexity, it is capable of feeding any geometry. The biggest disadvantage of this design is the difficulty of installation.
Pellet boiler structure: retort burner
To ensure that you do not make a mistake when purchasing, you need to pay attention to some factors. In some situations they affect the performance of the boiler.
Modern points of sale offer boilers with several types of burners. So, for example, a retort-type burner directs its flame upward. It is not particularly sensitive to fire and does not require the use of high quality pellets, as it can operate on low-quality fuel.
When purchasing, keep in mind that the retort burner can quickly become clogged and will require frequent cleaning.
If the device is not serviced on time, the heating device will stop working. However, despite the difficulties, experts recommend retort burners.
Pellet heating boilers: heat exchanger design
There are several heat exchangers designed specifically for pellet boilers. They can be vertical, horizontal, flat or tubular, with a large or small number of turns, vortices for the exhaust gases. All these are called turbulators. The installation can also be done without them.
Experts believe that the most effective models there will be those that include a turbulator and have several moves, at least 3.
Devices of this type are designed to reduce the temperature from 900 degrees to 110.
In this case, we can say that the vertical type design spends most of the energy on heating the coolant. Also vertical structures make it difficult for the ash to settle, and it begins to fall down due to gravity.
Another important detail when choosing a boiler is its brand. It is better to give preference to those companies that will not allow you to doubt their production, and whose boilers are often used for several years in the region where the buyer lives. If you decide to purchase one of the new models, you risk problems, so be sure to ask your consultant about the availability of spare materials in stock. Your boiler must receive a warranty and have a certificate from the service center.
Operating principle of a pellet boiler (video)
Boilers that run on pellets are becoming more and more popular, even regardless of the cold seasons. Experts say that a great future awaits them. Since they are easy to maintain and the result of their work is environmentally friendly, they represent serious competition to other devices. Proper use of such an installation will make it possible not only to save money, but also to obtain a reliable, practical heating system.
Relatively recently, a pellet boiler was a “curiosity” for domestic consumers. There were only a few models on the market foreign manufacturers, at very high prices.
At the moment, there has been a significant reduction in the price of products; several Russian enterprises began to produce boilers and pellets. Pellet equipment has become more accessible and its popularity has increased.
How does a pellet boiler work?
Pellet boilers for heating and hot water supply have relatively simple design and an internal structure consisting of the following components:
Pellet device heating boiler, after slight modification, is used for firewood, liquid fuel, briquettes, etc. For this reason, most manufacturers produce universal or multi-fuel units based on a pellet station.
How to choose a wood pellet boiler
In fact, choosing a pellet heating boiler is not as difficult as it might seem at first. You will need to determine several important points, and then select a station that fully meets your needs.In addition to the manufacturer, power and cost of the boiler, pay attention to: 
To select the right heating unit, you will need the help of a consultant. It would not be superfluous to make a design for the future heating system in order to take into account all the expected parameters of the boiler at the calculation stage.
Calculation of required power
You can calculate the power of a pellet boiler with the help of a qualified specialist using the services of online calculators. It’s quite easy to make approximate calculations yourself.For calculations you will need to complete the following steps:
- Find out the total heated area - for this, the length of the room is multiplied by its width.
- Calculated required power heat generator - it is generally accepted that for rooms with an average percentage of heat loss and a ceiling height of no higher than 2.7 m, the ratio 1 kW = 10 m² applies. Accordingly, for a room of 200 m², you will need a 20 kW boiler, 150 m² 15 kW, etc.
- Selecting a suitable boiler - domestic boilers low power, usually have a performance sufficient to heat a building of 400 m². The minimum power of pellet equipment is 15 kW. Modern models have smooth modulation, which allows, if necessary, to reduce heat production to 1-4 kW.
- Additionally, the heat consumption for heating DHW is taken into account. If you plan to connect a boiler indirect heating or a second circuit is built into the system, 10-15% of the reserve is added to the resulting power result.
Domestic or European
Despite the appearance of several dozen models manufactured domestic producers, the most popular pellet boilers are still produced by foreign companies.The following products are in demand:
- European boilers - offered by German, Czech, Austrian and Polish companies. The models are distinguished by high automation of the combustion process, optimization of the design: external and internal device. Companies offering equipment: , and others.
- Domestic boilers are characterized by low cost and many minor defects. The advantage of Russian units is their unpretentiousness to operating conditions and the quality of the fuel used. Companies that are popular, according to statistics: "", "", "DOZAMEX".
Cost of pellet heating boilers
The main disadvantage of pellet boilers remains their high price. Compared to conventional solid fuel units, the price can be 2-3 times higher. The pricing policy for pellet boilers is as follows:- Europeans are boilers German manufacturers, for household needs, will cost 450-500 thousand rubles. Identical equipment of Austrian and Polish origin can be purchased for about 300-350 thousand rubles.
- Domestic units - fully equipped stations are offered for 200-250 thousand rubles.
Installation of a pellet-granulated boiler
According to the recommendations located in the manufacturer's instructions, the installation of the boiler is carried out exclusively by a specialized team that has permission to carry out the work and the appropriate license. Gross violations during the connection process lead to refusal to provide warranty service.Installation rules are described in detail in technical documentation. Additional requirements are specified in SNiP and PPB. Pellet boilers are installed in accordance with the standards that apply to all solid fuel units.
Requirements for the premises under the boiler
The boiler room is a place of increased danger. Location requirements and technical specifications premises are specified mainly in the rules of the PPB:- The size of the room for the boiler is at least 12 m², provided the ceiling height is over 2.2 m.
- Forced and natural ventilation is required.
- The walls and floor of the room are lined with non-combustible materials: plaster, ceramic tiles.
- The base for the boiler is made taking into account the weight of the station. Optimally, preliminary pouring of the foundation.
- Place the station in such a way that servicing the boiler is easy to perform. All important nodes must be freely accessible.
- Natural light is a must.
Organization of continuous power supply
Almost all pellet boilers are energy dependent, therefore, during installation, the current rules for connecting electrical installations are taken into account:- The connection of the pellet boiler is carried out by an electrician who has the appropriate work permit.
- The station is powered directly from the switchboard. Cut-off machines are installed outdoors.
- The use of an RCD is mandatory.
- All metal parts of the structure are grounded.
- Long-burning pellet boilers have automatic controls that are sensitive to voltage changes, therefore, you will need to install a stabilizer.
The UPS for the boiler operates on the basis of high-capacity batteries. After a power outage, the uninterruptible power supply provides autonomous operation boiler for from several hours to 2-3 days, depending on the selected model.
Smoke pipes for pellet boilers
The choice of a chimney is associated with several characteristic differences in the operation of a pellet boiler:- Temperature in the combustion chamber - granular fuel is burned at temperatures above 550°C, in fact, the pellets melt on the burner. The chimney connected to the boiler must withstand an operating temperature of 450-550°C and short-term heating of about 1000°C.
- Chimney diameter - parameters and minimum dimensions described in the technical documentation. The cross-section of the pipe is round or oval.
- Draft characteristics - the chimney must provide stable draft in the pipe.
According to their characteristics, and are optimally suited for pellet equipment.