Water heating from the stove on firewood. Scheme, working principle

The issue of heating in winter time is acute for everyone who plans to build their own country house. Electrical equipment for most consumers is too expensive, and connection to the gas supply network is not always available everywhere. In this case, the alternative are well-known furnaces for dachas on firewood, which have not lost their relevance for many centuries.

Varieties

Depending on the needs, consumers can choose furnace equipment with a water circuit of different capacities. There are furnaces, equipped with a tank for storing wood pellets, as well as a mechanism for automatic feeding of pellets. It is a screw conveyor or pneumatic device.

Modern furnaces for wood-burning houses are equipped with a regulation system that allows to set the optimum operating mode, providing a specific temperature for a certain period of time. With a small load, fuel loading and ash cleaning should not be done often.

If a large volume of water is required for various domestic needs, it is recommended to purchase units in which 10% of the heat is used for heating purposes, and for heating the water - 90%, which will then be sent to the heating system or to the storage tank.

There are furnaces with a water circuit, which are equipped with a forced ventilation system, programming automation and a remote control.

Such equipment can be called universal heating devices that simultaneously combine the functions of titanium and the boiler. Thanks to this, water heating from a wood-burning stove is an ideal option for country houses, cottages and cottages.

Design

A classic oven consists of the following basic elements:

• A chimney;
• Boilers for burning products and smoke rise;
• A furnace in which combustion of firewood occurs;
• A sump for effective cleaning of the furnace from ash.

During the operation of the furnace unit, all four walls of the structure are heated. As a source of heat, you can use briquettes or firewood. The main material for the construction of the furnace is a red brick.

Principle of operation

Units with a water circuit are equipped with a heat exchanger built into the chimney or chimney duct. There are models that can function in the steam circulation mode.

Furnace for heating on wood can be made of boiler steel, cast iron, designed to work in high-pressure steam. These devices are used both as additional equipment and as the main source of heat.

A heat exchanger is installed inside the stove. Heated gases passing the heat of the liquid move along the channels of the heating tank. A furnace with a boiler in its design can have several reservoirs at the same time, which can significantly increase its efficiency. Water is heated in one tank, with increased heating in the second, the process of vaporization takes place.

To heat a large building with traditional stove heating, several furnaces will be required, while the consumption of coal or fuel will be quite high. Therefore, a more economical and alternative option would be a stove for water heating of a house on firewood, equipped with a special hot water boiler mounted in the furnace. Even with severe frosts for such a heating system, two-time lighting of the furnace will suffice.

Such devices are capable of heating the building even in the intervals between the furnaces. In the process of cooling, the pipelines give up their heat for another 5-6 hours, thus they carry out heating without fuel consumption. Water heating from a wood-burning stove has an efficiency of 80-85%.

Heat dissipation

For example, let's take a furnace with an iron boiler 35 cm high, 48 cm wide, 75 cm long and a water contour measuring 1020 × 1020 mm. In this case, the efficiency of the stove unit, if properly operated, can reach about 85%. With a two-time furnace, the heat output of the furnace is 6500 kcal / h (7600 W), and the heat output of the boiler is 15,000 kcal / h (17,500 W).

If we calculate the total heat output of a wood-burning stove with a water tank and a boiler, we get about 21,500 kcal / h (25,000 W). The use of this type of heating in severe frosts will allow heating the room up to 300 m ² .

The high heat transfer of the furnace unit is achieved due to the heating of the surface of the water boiler. The body of the metal tank is washed on all sides by hot gases. At the same time, the internal surface of the heating chamber also warms well, which makes it possible to keep the water boiler hot during a break between the furnaces (about 7-8 hours).

Thus, compared to conventional solid fuel boilers, water heating from a wood-burning stove is much cheaper.

Advantages and disadvantages

Despite the appearance of an incredible amount of technical innovations intended for heating the rooms, the owners of private houses prefer oven equipment. And for that there are many significant reasons.

Benefits

• Economical. Services stove will cost significantly less than the purchase of modern devices, their maintenance and installation. The furnace can be made of mortar and brick, which remained after the construction of the house. Repair and operation of such devices does not require large investments.
• Variability of the construction. A modern master can lay down an oven of any shape and size. It can be decorated with exquisite designer decor, painted in various colors. There are designs that combine a fireplace and an oven.
• High degree of maintainability. For many years of operation, this equipment requires only minor cosmetic repairs. It's much faster, cheaper and easier than driving an expensive unit into the service.
• The possibility of regulating the burning intensity in the furnace.
• The atmosphere of coziness, which is typical only for Russian old huts with stoves.
• The intensity and speed of warming up the air is determined by the position of the dampers.

disadvantages

• That the water heating from the stove on the wood would give off enough heat, it will take some time. Brick masonry is warming up for a long time.
• The presence of dry firewood and open fire are factors of high fire danger. When burning fuel, you will not have to leave your house and watch the stove.
• Ash, soot, sawdust from firewood, dust. In the room where the furnace is located, will have to clean more often.
• Uneven distribution in the residential space of heat reduces the level of comfort.
• Large overall dimensions of the construction reduce the useful area of the building. By its definition, the furnace can not be small, since its efficiency depends on its size.

Project development

As already mentioned above, water heating from a brick oven on firewood is a rather dangerous construction. Therefore, the development of project documentation is recommended to entrust to a specialist who will take into account all the subtleties.

Design Features

• Furnaces for cottages on wood, water heating in general, it is desirable to design even before the start of construction, to think over the optimal layout of the living space. The equipment should be located closer to the center to ensure free access to the firebox. It is not necessary to place the front part of the oven in the room, it is preferable to take it out into the interior corridor or hallway.
• In the case of close location of the unit and interior partitions, it is necessary to provide a ventilated indentation or air gap between them to prevent overheating of the wooden structures. For greater safety on the part of the furnace, it is possible to build a lining of fire-resistant materials or lay out baffles with partitions. This will reduce the fire hazard of the heating system.

Water heating from a wood-burning stove: scheme

First of all, it is necessary to determine the functional capabilities of the future furnace unit. Will it be used only for heating water or for other purposes. As a rule, a brick oven for water heating is performed in conjunction with the hob, which is relevant for country houses.

In addition, it is necessary to perform a complex system of chimneys. During the passage of hot carbon monoxide over them, the walls will heat up, and heat will flow into the room. They can occupy about 70% of the volume of the furnace, which is not always possible for small houses.

The main component of water heating from the furnace is a heat exchanger. This element carries out the transfer of heat energy from the combustion of fuel (coal, wood) to the heat carrier. The heat exchanger is located at the rear of the combustion chamber.

Choosing the most suitable scheme, you can begin construction. The optimal option will be the purchase of a finished steel model, which can then be covered with a protective fireproof brick in 1 layer. However, if a large, powerful unit is required, it is recommended to do it yourself.

Furnace yourself

The construction of the furnace begins with the installation of the foundation. It is important that he is not tied to the foundation of the house. To do this, a concrete screed is poured into the ground, its height should not exceed the floor level by more than 5-7 cm. Only after this it is possible to start the erection of the structure.

• The first rows of the ash pan are laid in accordance with the chosen scheme.
• Next, the ash door is mounted and the structure is bricked. The door should be made of cast iron, measuring 19.5 x 24 cm.
• A combustion chamber is similarly produced.
• It is preferable to install a ready-made flue duct of circular cross-section.

It is advisable to use refractory chamotte brick for the ash pan and furnace chamber . For cladding, you can choose a regular silicate brick, since it has a good heat capacity.