Solid fuel boilers long burning with a water circuit for the home – heating units designed for use in non-gasified cottages, houses and cottages. The low price of fuel, their use as a reserve source of heat and the ability to burn waste from a horticultural farm in boilers made solid fuel boilers quite popular among owners of suburban housing. Such equipment is especially important in the conditions of the continuing trend of increasing gas prices.
Solid fuel boilers long burning with a water circuit for the home: types of units
Unfortunately, there are still many settlements and holiday villages, where gas lines are only planned. In such conditions, equipment becomes an alternative, the fuel for which is coal, wood, or fuel pellets. To ensure a comfortable microclimate and the availability of hot water for domestic needs, resorted to the use of solid fuel boilers long burning with a water circuit for the home. The convenience of their use is that the equipment is loaded once a day (in some models there is a load once a week). Thanks to this, the solid fuel boiler of long burning has a high (up to 95%) efficiency.
According to their design, boilers with a single combustion chamber with the use of a bottom blast and boilers with a two-part furnace with a lower and upper blast (pyrolysis boilers) are distinguished. Types of housing solid fuel heating boiler with a water circuit: cast iron or steel.
The device of a single-circuit boiler, providing heating of the heat carrier for the heating system batteries, has the following structure:
- firebox – the combustion chamber of solid fuels;
- ashpot – a collection of waste generated during combustion;
- chimney – channel for removal of exhaust gaseous products of combustion;
- the jacket is a heat exchanger built into the firebox with water.
The principle of operation of the boiler is as follows: a fuel is placed in the combustion chamber, which, when burned, releases heat. The heat exchanger accumulates heat and gives it to the coolant, which circulates through the coil. Warm water flows into the batteries, and the cooled water returns to the boiler.
The difference between a double-circuit solid fuel boiler for a house is that it has an additional heat exchanger (coil), which is used for hot water supply. This heat exchanger is connected to the water pipes, ensuring the supply of domestic hot water.
There are two methods for connecting and positioning a DHW circuit:
- Flow-through heating mode. With this method, the water heating circuit coil is integrated in the jacket. The water coil heats up due to the energy of the heating medium of the heating system. Water moved through the coil is heated to 45 degrees. The effectiveness of such a system is up to 8 liters per minute.
- Accumulative heating mode. Such a system provides for a boiler (water heating tank) built into the chimney duct or the main heat exchanger. Heating is carried out by hot air or coolant heating system. Depending on the flow of hot water, cold water is supplied from the water supply system to the boiler and heated to 90 degrees. With this scheme, the DHW circuit is able to provide a volume of water in 2 times the volume of the boiler, which will contribute to excessive consumption of fuel.
When water is heated, due to expansion, its natural circulation occurs: when heated, it moves up, and when cooled, it goes down. Wood burning boilers are able to heat only a certain amount of water. This parameter should be taken into account when choosing a boiler.
The use of solid fuel boilers for heating private homes. The use of solid fuel boilers for heating private homes can significantly reduce the cost of fuel.
To improve the efficiency of the equipment, it is proposed to equip the boiler with a circulating pump. With its installation, the efficiency will double, but then the functioning of the boilers becomes volatile. If the electric power is supplied intermittently, it is recommended to complete the boiler with a switch (bypass) capable of transferring the forced movement of water into the natural one.
Helpful advice! When purchasing a boiler, you should choose a model that will provide domestic hot water without supplying water to the heating system. This will allow to use hot water in the summer season.
In order for the boiler for long-term combustion of the fuel not to work on the heating of radiators, but to provide heating for domestic use, it is equipped with an electric heater. This boiler is called a hybrid and is a multifunctional equipment.
Equipping boilers with additional equipment (for example, a fan to provide draft in the chimney, a pump for pumping hot water in the pipes) makes the equipment volatile, on the other hand, connection to the network makes it possible to automatically control the process.
We offer for viewing the video: “Solid fuel boiler for a long burning with their own hands”:
A feature of the functioning of pyrolysis boilers is that in them the combustion chamber consists of two separate sections. In one section of the furnace, solid fuel burns, in the other, combustion products. When in the cold season, firewood (often raw) is laid in the first section, during their combustion, steam appears. To eliminate its negative impact on the combustion process, use the second section of the furnace. It is in it that the hot gas moves, which removes excess moisture using a secondary stream of air. This method is called the method of double blast. The two sections of the chamber are separated by a grate, where the firewood lies, through which the primary blowing passes. Pyrolysis boiler operation is promoted by the forced draft generated by the smoke exhauster.
The procedure of the pyrolysis unit:
- solid fuel (firewood) is laid on the grate;
- the boiler is ignited, the fire door is closed and the exhauster is turned on;
- during combustion, a high temperature is created inside the chamber, which contributes to the formation of charcoal, carbon monoxide and volatile formations of hydrogen and nitrogen;
- all these products enter the second section of the chamber, where a secondary air flow is mixed with them and these products are burned;
- heat from the combustion of these products is re-supplied to the first section of the chamber.
As a result of this design of the boiler, a sufficiently high temperature is maintained in it, waste from the combustion of firewood is thermally decomposed, forming pyrolysis gas. Thus, solid fuel is used rationally, and the heat from the combustion of waste is reused.
For the correct choice of a solid fuel boiler for heating a private house, it is necessary to analyze its characteristics:
- In the pyrolysis units, repeated supply of air is used, which ensures the duration of the burning of the fuel intake, extending it to 10-12 hours, and the burning time of the similar installation in the ordinary boiler is 4 hours. In terms of efficiency, pyrolysis boilers are loaded less frequently and less fuel goes;
- In pyrolysis boilers, firewood is burned with virtually no waste. Ash remains the minimum. This, in turn, facilitates the maintenance of equipment: it is not often necessary to remove ashes from the boiler and clean the flue;
- two-stage combustion, which reduces the excess air in the chamber, improves the performance of the pyrolysis boiler;
- in the presence of two combustion chambers, it becomes possible to control and regulate the combustion process. Pyrolysis boilers can be automated, which is completely impossible in conventional boilers;
- pyrolysis boilers can take to ignite logs of a rather large size, which, in turn, saves time for cutting wood;
- easy and affordable installation – does not require permits, you can install the equipment yourself.
The advantages of pyrolysis boilers for solid fuels for heating a private house are many, but there are some drawbacks that should be mentioned:
- high price;
- dependence on electricity – due to the use of the exhaust fan;
- in some cases, the discrepancy with the declared power characteristics;
Helpful advice! Before you buy a solid fuel boiler long-burning, read reviews about its manufacturer. Very often there are models with an inefficient pyrolysis process.
- the use of boilers in incomplete power leads to the formation of tar, clogging the flue;
- for correct operation of pyrolysis heating solid fuel boilers with a water circuit, it is required to mix hot water to the liquid that enters the boiler for the second time;
- the return temperature must be at least 60? С, otherwise condensate will appear in the gas path, which will lead to corrosion.
What you should pay attention to when choosing a suitable model of a solid fuel boiler:
- power unit. If you purchase a double-circuit boiler for hot water supply, you should choose a unit that will have enough power to heat household water;
- hot water circuit performance. It is necessary to calculate whether the volume of water heated by the boiler is enough for domestic needs of the whole family;
Helpful advice! To provide hot water to a home where a large family lives, you should purchase a boiler model with an integrated boiler or provide for the installation of a heat accumulator.
- convenience and frequency of service. Pay attention to how often you have to load firewood and clean the ash pan. Give preference to models with a volumetric bunker, where cleaning is done once every three months, and the duration of burning reaches five days;
- materials of which the boiler is made. Equipment made of cast iron is durable (service life is up to 30 years). Coil for hot water should be made of steel or copper.
Modern models of solid fuel boilers long-burning can completely replace gas. In addition, due to high performance, they are environmentally friendly and economical. Acquisition of a solid fuel boiler with a water circuit will be beneficial if you consider all the requirements and parameters of this equipment.