The constant increase in the cost of energy carriers and expensive gas connection requires looking for other types of heating devices for the heating system. An electric or gas heat source is an alternative to a solid fuel boiler. The article introduces the types and characteristics of solid fuel equipment, its pros and cons, methods of protection against overheating.
Solid fuel boilers types and characteristics
Solid fuel boilers are of two types:
- classical, in them, during the combustion of fuel, heat is released.
- pyrolysis, with the release of combustible gas when the temperature rises from the combustion of fuel, and its supply to the combustion chamber, where it is burned.
The second type of units is considered more perfect. They have a fairly high efficiency, the fuel burns out almost completely, the power changes in a wide range, there are fewer requirements for the chimney, which ensures the presence of a blower in the design. But their price is much higher, they have more requirements for fuel, its maximum moisture content should not exceed 20%, and for the water temperature in the boiler.
Solid propellant units are cast iron and steel. The hardness of the water is not so important for the first, but they need to ensure the correct temperature of the make-up liquid. The supply line for feeding the heating system must be warm water, not cold tap water. This will protect the heat exchanger from destruction due to temperature changes. Cast iron heat exchangers are heavier than steel, which increases their inertia. They are less frequently cleaned without reducing efficiency, resistant to corrosion, which increases the service life, but also increases the cost.
Boilers can be volatile and non-volatile. The first type is models with an electric control panel and a fan that blows air into the combustion chamber. Usually these are pyrolysis boilers made of steel or cast iron. Sometimes there are non-pyrolysis steel products with a built-in fan that works like a supercharger. Non-volatile equipment also works without electricity, where the heating system has natural circulation. But such models are less comfortable and economical.
The type of fuel affects the power of the equipment. Most often used: brown coal, anthracite, coke, firewood, fuel briquettes, wood chips. The use of low-calorie materials can reduce the boiler output by up to 30%.
Solid fuel boiler pros and cons
Before you make a decision and buy a solid fuel boiler, you should familiarize yourself with the advantages and disadvantages of the equipment.
The pluses include:
- high ecological cleanliness;
- affordable cost;
- the possibility of using fuel of different fractions and sizes, which allows you to change the power of the boiler and the period of its operation (with a decrease in size, the power increases and the time during which the fuel burns decreases);
- safety during operation, proper installation ensures energy savings and prevents explosive situations;
- minimal risk of fire.
The disadvantages of the equipment include the formation of soot on the walls of the boiler, the frequent loading of fuel for continuous operation. It is not always possible to quickly provide the maximum power of the unit.
Protection of a solid fuel boiler against overheating
To avoid troubles that can lead to boiling and explosion of the boiler, it is necessary to ensure its protection against overheating. Its main reason is the high inertia of the unit during fuel combustion. This process cannot be completely stopped until the firewood or coal runs out in the combustion chamber. The fuel will continue to burn in it, therefore, at the outlet of the coolant, the temperature can reach 100°C or more. This will lead to deformation of plastic and metal-plastic pipes and failure of the entire heating system. Special devices are used to protect it.
- Heat exchangers for cooling. They are built into the boiler or installed at the outlet of it. A thermal valve is connected to the unit, which is set to 95°C. When a high temperature is reached in the boiler, it opens, and cold water, passing through the heat exchanger for cooling, washed by the hot coolant, begins to cool it until the temperature in the boiler becomes acceptable.
- Valves for switching. Its purpose is to block the supply of overheated coolant to the system and supply cold tap water.
- Installation of a large capacity storage tank. Such a device allows not to install additional valves.
In the first case, it is necessary that there is a constant supply of water. In the second, the superheated coolant is drained into the sewerage system, and water must be supplied under high pressure.
The best way to protect is to install a solid fuel boiler and a heat-insulated large-volume tank (buffer) with water between the heating system and the boiler.
The correct operation of solid fuel boilers will not be possible without the correct installation of the chimney. At the same time, it is necessary that:
- was made of heat-resistant materials that can withstand temperatures of at least 500 ° C, resistant to corrosion;
- had good thermal insulation;
- was at least 4 m high and over 180 mm in diameter.
But it is impossible to greatly increase the dimensions of the chimney in order to avoid the formation of an air lock that prevents smoke and gas from escaping.
But the main thing is to follow the recommendations of manufacturers and take into account the requirements of building codes during installation. Electric or gas units are an alternative to solid fuel boilers that can be installed as backup heat sources. But it is important to ensure their protection from possible overheating. The use of such modern equipment requires an appropriate acid-resistant chimney. Only the right choice, installation and operation of solid fuel boilers will ensure the safe operation of the entire heating system.