A coal-fired cat is an indispensable thing for everyone who wants to have their own heating source, independent of a centralized system, or in the absence of it.
Principle of operation
These devices are not in the full sense of the word modern and innovative, but the main models on the market are quite advanced devices. A long-burning coal-fired boiler can heat the room for a long time, it does not require constant monitoring of its operation - this distinguishes it from the fireplace.
The principle of operation of such devices is based on the constant injection of hot air and the permanent burning of solid fuel coming from top to bottom. The entire combustion process is safe, as it is absolutely controlled.
The prevalence of these devices and their popularity is due to the low cost of coal, which goes to kindling, as well as the high efficiency of this heating device.
Benefits
The high efficiency of the coal-fired boiler is affected by the design feature. Like any other heater, this device has its pros and cons in practical use.
The advantages of the device include the following qualities:
- full consumption of fuel material - coal burns to the ground and burns rather slowly, thoroughly warming the house;
- air supply is limited - pure oxygen is kept in the house;
- the whole process of temperature boosting is created by built-in automation, which ensures the full consumption of raw materials (about 1-2% of coal may remain unused);
- there is no need for constant monitoring and regular maintenance - the boiler is unpretentious and reliable in operation;
- loading chamber volume - it is possible to lay almost 350-500 l of fuel feed per 1 time, which allows to extend the heating time to several days;
- it does not take much time to clean the chambers and the boiler itself;
- the combustion process occurs evenly, is controlled, less soot is produced, there is no overheating of the coolant.
Today, heating with a coal boiler is the most comfortable option for heating a private house for its residents.
disadvantages
In addition to the obvious advantages, coal systems have some disadvantages in their work. They are few, but they are quite significant:
- the high cost of the coal-fired boiler against the background of conventional devices (1.5-2 times higher);
- similar performance with other types of heating at a higher cost;
- dependence on the source of electricity;
- the lack of the possibility of additional laying of coal after the start of the combustion process - it is impossible to report additional portions until the previous ones are completely burned.
However, the overall effectiveness of coal-fired appliances still attracts buyers so much that these flaws stop few.
Varieties of heating appliances
Modern manufacturers offer mainly two types of such devices. Coal heating boilers are as follows:
- solid fuel with the principle of burning "top to bottom";
- automatic, with a burner and auto-feed of coal.
Each variety is purchased by the buyer depending on the availability of funds and the prospective intensity of use of the device. Both types of boilers are quite versatile, they can use both wood and coal briquettes for burning.
The choice is also made on the basis of operating characteristics, after analyzing the advantages and disadvantages of each type, especially the possibility of supplying the appropriate fuel.
Fuel difference
A significant drawback of wood is its burning rate and the constant need to control the heating process, when it is often necessary to add raw materials to the furnace.
In turn, coal for boilers is much more economical and more convenient. It burns or smolders much longer; for it long-term combustion chambers are developed, which allows stably and for a long time to keep heat in the system.
What to load into boilers: coal, firewood or other raw materials - each owner of the house decides for himself. It should be borne in mind that the lack of firewood is in their low density and mass. Coal gives more thermal energy with a similar volume, burns much longer.
But coal also varies by brand - different types of this fuel burn faster or slower. Moreover, even ordinary
coal grades can increase the intervals between downloads by several hours (depending on the volume of the loading chamber, the interval can be up to 4-5 hours).
Solid fuel boilers
Coal-fired solid fuel boilers are popular cylindrical devices that have a spacious combustion chamber. As the fuel burns up from top to bottom, the mass of coal decreases, the residues fall on the grate of the ash chamber. A special fan controls the combustion. Coal is crushed by the load, the air mass diffusers work from below.
The intensity of work is dictated by a built-in thermostat with a chain drive. Air is supplied naturally. In some brands of devices, the temperature is regulated by sensors that report measurements to the control unit, and it controls the flap of the telescopic pipe.
Automatic
An automatic coal-fired boiler is usually designed in the form of pellets. They allow you to use a burner and a spare hopper for fuel. The heat exchange sector is similar to that of a traditional boiler - the fire tube principle or multi-pass unit is used.
The burner has a retort design: bowl, feed auger, gearbox, electric motor, fan blows air. Coal moves from the hopper along the auger and enters the bowl, and through the side slots air enters it through the fan forcing.
All processes in such a device are automated - from ignition to final combustion.
The fuel supply is not limited, it can also be added. Such a boiler requires stopping and cleaning, additional maintenance approximately once a week.
Additional details
A long-burning coal-fired boiler has the ability to make design changes in order to modernize it and increase efficiency. For example, for more uniform heating of the entire house and continuous operation, you can buy additional components:
- The UPS device is an uninterruptible power supply that will protect the house from power surges. After a power outage, the procedure for pumping air into the fuel chamber will still continue. The duration of the boiler in this case depends on the total capacity and energy intensity of the UPS.
- A circulation pump that will provide additional support for the natural circulation of the heat carrier. Natural processes, for all their simplicity and efficiency, are not always a profitable option or unsafe in operation, contrary to safety precautions. With the pump, you can create a forced flow of heated liquid and thus significantly increase the performance of such an assembly as a coal boiler.
- Indirect heating boiler - relevant for a single-circuit device. The boiler will provide the whole house with hot water heated by the appliance.
Cost and Brands
Such a boiler, the average price of which is $ 300-700, depending on the model, is not an affordable option for most buyers, even taking into account its high efficiency. Typically, the need for autonomous heating using coal arises among residents of rural areas, in cottage villages, farms. Of course, such a price justifies itself, given the cost-effectiveness and convenience of the device.
However, it is possible to reach the payback level only after 5-6 years of constant use of such a coal-fired boiler with regular supplies of raw materials.
Today, such brands of boilers as Depro, Heiztechnik, Mart, Stropuva, Liepsnele and others, including domestic ones, are widespread on the market. Most of the issuing companies are interested in distributing their products and go towards the customers - declare stocks, offer discounts or produce simplified models in the economic segment. Some solutions and technologies can significantly reduce the price of devices with the principle of upper combustion.
Therefore, we can naturally expect a decrease in prices for this type of heating systems.
Owner reviews
The opinions of users of this device do not differ much in the overall assessment.
The coal-fired boiler is recognized by most buyers as a very profitable and convenient device to use. The Lithuanian products of Stropuva have a good reputation, which, unfortunately, not everyone can afford. The German coal-fired boiler Heiztechnik is also well-deserved.
The fact that sometimes in a particular area there are difficulties with the supply of fuel stops many. It is easier and cheaper to order wood, despite its high consumption. The boiler, the price of which for most is unbearable, becomes the cherished dream of many farmers and residents of suburbs or villages. After all, in their opinion, with such a heating device, you do not need to think about livestock conditions, it is easy to heat the house and outbuilding.
In general, the coal unit is a profitable and worthy acquisition for the economy, which will solve a lot of pressing issues.
So, we found out what coal-fired boilers are.