Heating from a simple stove. Stove with a heat exchanger: how to make water heating from a stove. Pros and cons of various heat exchangers

02.11.2019

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When planning to acquire their own country cottage, almost every future developer is forced to think about how to heat it in the winter. If there is gas in the village, for obvious reasons there is usually no dilemma. But when blue fuel has to look for an alternative, then the choice is quite difficult for a city dweller. Due to "voltage surges" and power limitations, rural electrical systems are too unreliable. Diesel boilers and liquefied gas units seem to be autonomous, but the price of such heating is too high, and the equipment is not cheap. And stove heating of a private home, which is accessible in all respects, seems to some to be something conservative and low-tech.

Meanwhile, heating using a stove in many cases is the best option for heating a country home, both when people stay permanently and during periodic visits. Solid fuel stoves have long proven their practicality and efficiency, but citizens who have not encountered them before are captivated by common myths and have a poor understanding of their advantages and disadvantages. It’s worth figuring out what a good old stove can do, let’s try to debunk these myths.

A country house with stove heating is beautiful and functional

Operating principle of heating stoves

Heating by stove is local. Fuel (usually wood or coal) is burned in a fuel chamber with air supply. Flue gases, under the influence of natural draft, move through long channels to the vertical exhaust passages and are removed outside. During this time, they heat the brick mass of the furnace, and the hot stone, in turn, releases heat into the room.

Myth No. 1. The stove must be heated continuously, and firewood must be constantly added.

This mode of operation is inherent in various potbelly stoves - they heat up quickly and cool down quickly. However, brick ovens are designed for 1-2 fires during the day, and each time all (or almost all) of the fuel is loaded into the chamber. Of course, you will need to set the valves in the right position in time and periodically remove ash from the ash pit. The greater the heat capacity of the stove, the better the house is insulated, the less often it needs to be heated, once a day - this is a fairly common option.

Advantages and disadvantages of a country house with stove heating

Of course, there are both positive and negative aspects that become more or less relevant in certain conditions. It is worth considering the feasibility of stove heating as a whole, weighing all the pros and cons.

The advantages of heating with a stove

The cost of constructing a furnace (as well as its maintenance) is several times less than that of competing systems of similar power.
Full autonomy. There is no connection to electricity, water, or gas pipeline. For example, firewood is publicly available and the price is reasonable almost everywhere.
There is no coolant liquid - there is no danger of defrosting the pipes. Therefore, such heating is excellent for a summer house that is visited from time to time.
There are combined design options with the function of cooking or heating water. And also with a dryer, oven, fireplace, etc.
Finding ready-made projects for houses with stove heating is not a problem today.

Disadvantages of furnace systems

A stone stove is a large device; it will take up a couple of square meters of space in the center of the house (although there are also quite compact models measuring about 1 m2 across the floor).
It takes time to initially warm up the furnace mass (then it does not cool down completely between fires).
Relatively low efficiency in terms of heat transfer (increased by lengthening the strokes, using caps and “free movement of gases”).
There is no way to automate processes.
It is advisable to build a heavy stone stove at the stage of building a house. The layout of a house with stove heating is the prerogative of specialists.
Firewood must be properly prepared, and in advance (for example, dry freshly cut wood for at least a season, store it under a canopy).

It is better to place the stove in the center of the house

Myth No. 2. The temperature inside a stove-heated house is very unpredictable

Some unevenness sometimes occurs, this is explained by the fact that the strongest heat transfer occurs at the end of the firebox, and by the time of the next session the channels have already cooled down. This problem does not exist if the stove is massive enough for a particular building, and its channels are folded, for example, not into a quarter of a brick, but into half. No less important is the heat capacity, as well as the insulating characteristics of the cottage’s enclosing structures. Increasing the number of fireboxes also helps make the temperature more uniform. Let's say that instead of just a long morning melting, two shorter ones are used (morning and evening).

What is unique about the design of stone stoves?

In this case, the device includes not only a heat-generating unit, but also heat-conducting channels and heat-transferring surfaces. Each oven consists of the following elements:

fireboxes and blowers;
chimneys (channels);
outlet pipe;
mirrors, heating panels (surfaces that give off heat);
grate bars, doors, valves;
independent foundation.

There are hundreds of design options for stone stoves; each device will differ in configuration, size, functionality, and thermal efficiency. Many models received proper names, but according to their purpose and special abilities they are classified as enlarged groups.

By type of calorific value:

Long burning stoves. There may be air ducts, relatively thin walls - they quickly warm up the room, but quickly cool down, which means they need to be heated more often and for longer. Well suited for the dacha, where they are rarely visited.
Fast burning stoves that give off heat for a long time. The combustion session is shorter, there may be fewer fireboxes themselves, since the walls of the channels are more massive, and in general the masonry is more voluminous and heavier (they accumulate more heat).

Metal water heat exchanger

You can also distinguish types of stone stoves by purpose and additional components:

heating;
heating and cooking;
with built-in fireplace;
with oven, barbecue, grill;
with water tank;
with water or air heat exchanger.

Myth No. 3. It is impossible to heat a two-story house with stoves. You need two separate stoves.

This is, of course, not true. There are at least two normal solutions. Firstly, there are models of two-story stoves that have one firebox, but elongated heating surfaces passing through the ceiling. By the way, these devices are quite compact in terms of footprint. The second option is to use a coolant, for example, in a water circuit or air duct system. The situation is approximately the same with the heating of small apartment buildings.

How to choose the power of stove heating in a private house

The main thing to do is to choose the right size oven; more precisely, we will be interested in the area of the heated surfaces. Here it is necessary to take into account the total heat loss of the building. It is believed that the stove should replenish them with an error of 10-15 percent when fired twice. To determine the required thermal productivity, there is a simple formula (the task is to heat the room to +18, with an outside temperature of -30). To do this, the cubic capacity of the house is multiplied by a factor of 21 and the value is obtained in kcal/hour. For reference: one square meter of the mirror of stone stoves produces on average about 300 kcal/hour, the stove of heating and cooking models emits approximately 600-900 kcal/hour, the heating panel – up to 1200.

Myth No. 4. Stove heating is low-power.

In fact, there are stoves for houses of 100-120 square meters and are actively used. And models of 5-7 kilowatts (50-70 m2) are generally considered classics.

Such a stove will give off heat for a long time

A simpler calculation method is also used - for every 10 square meters of cottage area there should be about 1 kW of furnace power. For reference: this is about 860 kcal/hour. Naturally, these values are approximate; the configuration and specific characteristics should be calculated individually.

As a conclusion, one more myth – No. 5. Brick ovens are very difficult to build.

A professional stove maker is a person belonging to a special caste. However, practice shows that many home craftsmen can master the technology and make stove heating themselves. Although, it should be understood that there are also difficult designs that amateurs should not attempt. In any case, the plan for a house with stove heating must be approved by specialists.

Video: stove heating

The time has long passed when stove heating existed in almost every home. Today it has been replaced by centralized heating, gas boilers, electric heaters and even solar panels. Nevertheless, this oldest method of heating a home has not been completely forgotten and is still popular in some parts of the country.

How does the stove work

There are many types of stoves used to heat a house: Russian, Dutch, fireplaces, etc. Let's consider the principle of operation on such an ancient structure as a Russian stove. It never went out of fashion, remaining the object of attention of specialists. To build it, complex equipment and expensive materials are not required. It is economical; with little fuel consumption, the room quickly warms up and does not cool down quickly.

Before the masonry begins, a foundation is made - a brick, wooden, stone or concrete foundation. Above it there is a stove where firewood for kindling is stored and dried. The oven is closed by a trough-shaped vault on which bedding is laid: brick chips, sand. The bedding is placed on top under the cooking chamber. This is an integral part of the firebox.

After a short heating, a Russian stove cools down for almost a day; in addition, you can cook in it. This is ensured by a bending with a top-overpipe, which ends with a nozzle. There are recesses on the side of the hood for storing smoldering coals and collecting ash. The combustion chamber plays the role of a gas-air economizer where heat exchange occurs.

The firebox, which is the heart of any oven, is divided into a crucible and a baking chamber. Under the furnace is made inclined. The heated air takes part in cooking, then rises to the roof of the furnace. Almost any fuel burns in the furnace, with a small amount of soot deposited. A Russian stove may not be cleaned for decades. The main secret is the complex labyrinth of the smoke channel.

Which stoves are suitable for heating a home?

Home heating equipment requires a careful approach. There are several options depending on the material. The stove for heating a house can be metal or brick. Metal construction is financially beneficial. But it is better to install it if the owners do not live in the house during the cold season, since a steel stove cools down as quickly as it heats up. This option is good when you only need to warm up one room. It takes a little wood.

A brick structure is more effective for uniform, long-term heating of several rooms at once. Construction requires skills, so it is better to contact a specialist. This is especially true for the Russian stove, which only a master stove maker can build. It is appropriate to install a brick building in a house where people live permanently. It takes a long time to warm up, but it also cools down slowly.

Brick stoves are divided into cooking-heating, fireplace-type and Russian. They install a fireplace if they want to make the interior of the house special and create a cozy atmosphere. Cooking and heating buildings perform two functions: heating the room and cooking food. The Russian oven can be used both for cooking and heating, and for drying mushrooms and berries. In addition, you can lie on the floors.

Advantages and disadvantages of heating with a stove

The main advantage of this heating is its complete autonomy. Heating does not require additional devices or sources in the form of electricity, a pump, etc. The availability of materials and the possibility of self-laying are also of great importance. To build a complex structure, you need a stove maker, but if you carefully study some of the subtleties, then even a beginner can handle the construction of a simple stove.

Such a house can be left for any period of time without fear of the system defrosting - nothing will deteriorate or freeze. If everything is put together correctly, then in cold weather it will not be difficult to light the stove through the summer chimney. A stove is a battery whose walls remain heated throughout the day, which is facilitated by good thermal insulation of the room.

There are also disadvantages of such heating, including the inability to heat a large number of rooms. The problem can be solved by installing a circulation system. Although in this case the very principle of heating with a stove in its pure form is lost.

The large size of the structure is another undesirable aspect. This disadvantage is partially compensated by its versatility. In addition to heating the room, it is possible to cook food and dry clothes.

How to make stove heating in a private house

When installing a stove for heating a private home, the priority is to balance the heat output of the stove and the heat loss of the room. If all requirements are met, the temperature in the house will be optimally maintained throughout the day. The necessary parameters can be provided by a stove burning wood or other fuel with the installation of a water circuit that is connected to the radiator system. There is also an air heating method.

Water stove heating

In this case, the stove operates on the principle of heating the room with a solid fuel boiler. The only difference is that the walls of the boiler do not participate in the heating process. When burning, the stove heats water in the radiators while the fuel burns. After cooling, its surface heats the room for some time. It is rational to carry out water heating from a stove in the private sector, where there are no gas pipes.

It is possible to make water heating in a house or country house. The stove design must contain a register (heat exchanger) installed in the firebox. Water heating is connected to the heat exchanger. The design of the register can be any, the main thing is that the circulation in it is uniform, which ensures the maximum temperature of the coolant. The heating circuit contains important nuances, so design and installation must be carried out by a specialist.

Air stove heating

Air heating is also made on the basis of a brick oven, the principle of which is to supply air heated to the required temperature in a boiler or heat exchanger. The air goes through ducts or enters directly into the room. Thanks to the shortened path, the air flow does not have time to cool down, and the house warms up evenly.

The greatest amount of hot air transfer occurs when the chamber is installed above the firebox. Circulation is provided by fans or naturally due to the different densities of hot and cold air. Forced ventilation allows you to control the process by regulating the microclimate in various rooms of the house.

Steam stove heating

Steam is also used as a coolant. Many people confuse steam heating with water heating, but they are significantly different from each other. Using steam increases heat transfer, and the room warms up much faster. The pipes are not filled with water, and the heating starts easily even after a long break. In addition, a steam heating system is cheaper than a water heating system, which requires larger diameter pipes.

One of the negative aspects is the short period of work. The steam system is poorly regulated; rooms are heated unevenly. There is another undesirable moment when, when filling pipes and radiators with steam, an unpleasant noise is created. In addition, with steam heating, the heating of the pipes is so strong that touching them poses a high risk of burns. Therefore, this method is more recommended for garages, warehouses or other utility rooms.

How to increase stove efficiency

To increase the efficiency of a wood-burning stove, the heating system should be improved by connecting a liquid circuit. The circuit is similar to that used when connecting the boiler. The only difference is that heat production when using a solid fuel boiler for a liquid system is primary. For a stove, the primary factor is heating the house using air exchange.

To retain heat for a longer period of time when burning wood, a liquid accumulator is inserted into the system. During fuel combustion, it helps to accumulate heat, which is then gradually supplied to the heating system thanks to the mixing unit. To maintain heat throughout the day, you will need several stacks of firewood. You can make one bookmark in the morning. A comfortable temperature will be maintained in the house until the evening. Then you can bookmark again.

Even more effective is a combined heating system, which includes pipes, radiators, a heat generator (furnace), a heat accumulator, an air temperature sensor, and a mixing unit, which is controlled by an air temperature sensor or a water temperature sensor in the heating system. This installation is complicated and must be done by professionals, since all components of the system are tied to the wood stove.

The efficiency of the combined heating system is high. One stack of firewood made in the morning is enough for the whole day. For longer breaks between fireboxes in the cold season, it is necessary to install a more capacious heat accumulator, ensuring a stable temperature in the house for the entire time the owners are away. It is also important not to forget about the fire safety of the entire heating system.

Every year the construction of individual housing increases, the popularity of private country houses is increasing. In modern construction, a large number of heating systems are used, but conventional stove heating with a water circuit is also widely used, even within the city, where it is not always easy to buy firewood.

Humanity has been heating their homes with firewood since ancient times; stoves in homes have been modified over time, and boilers with a water circuit have been invented for them.

Advantages of a water circuit

A conventional wood-burning stove distributes heat unevenly - it is hot near the firebox, and the further away from the stove, the colder it is. It’s uncomfortable at home because the temperature is different everywhere: I went to watch TV and it was cool, but I came to the kitchen to warm up. With water heating at home there are no such inconveniences; on the contrary, all the heat is distributed evenly throughout all rooms.

In addition, the stove can not only heat, such wood-burning heating is usually installed above the hob stove, that is, you can cook, which increases efficiency. A stove with a water circuit is, in fact, a solid fuel boiler, but here, in addition to the built-in system, the stove itself and the chimneys additionally bring heat into the house, which remain heated for a long time even after the combustion is completed.

Furnaces with a water circuit are widely used in rural areas where there is no gas supply. When choosing water heating, you do not need to buy an expensive industrial gas boiler. A wood boiler is an economical way to heat a house.

Brick stove with water heating - cons

One of the disadvantages of the water circuit is that the boiler reduces the useful volume of the firebox. To compensate for this moment, when laying the furnace, it is necessary to provide the required width of the boiler. If a heat exchanger is installed, firewood will have to be added more often to the finished stove when firing it.

Craftsmen recommend moving the stove when installing a water circuit, since thermal energy will be spent on heating the firebox, leaving the walls of the stove poorly heated. Only the upper part, where the chimneys are located, will warm up well.

Houses with water heating must be heated regularly in winter, otherwise the entire system may freeze and fail.

Principle of installation and operation of the system

Combined heating system for a private house

A boiler is installed in the firebox, two pipes are connected to it - one supplies hot water, which is sent through the expansion tank into the system, the other returns water back to the register. Thus, water circulates in the system due to the force of gravitational law.

Often, small but powerful pumps are installed for good circulation. Such a pump is usually installed on a water return pipe (return); this method is especially effective when a large room is heated, which allows you to maintain the temperature in all parts of the system almost the same.

How to build a water stove at home?

There are three ways to do stove heating with a water circuit with your own hands:
buy a steel stove from a manufacturer whose services include system installation;
hire a craftsman - a specialist will select the material, make the device, lay out the stove and install the boiler;
do it yourself.

How to make such a stove yourself

Can you make such a system yourself? Quite, just experience in welding and bricklaying when building a furnace is enough. First you need to prepare the boiler (register, coil, heat exchanger).

You can buy such a device or make it yourself using sheet iron and pipes. Since the full process of manufacturing and installing a water circuit cannot be summarized in a short review, the main recommendations are presented below.

For the boiler, a sheet of metal with a thickness of at least 5 mm is used, and its design is made in such a way that there is maximum heating of the water for further circulation. The boiler, welded from sheet steel, is easy to manufacture and operate – it is easy to clean.

But such a heat exchanger has a smaller heating area, unlike a pipe register. It is difficult to make a pipe register at home yourself - you need an accurate calculation and suitable working conditions; usually such boilers are made to order by specialists who themselves install the system on site.

The simplest method of a solid fuel heat exchanger is a regular potbelly stove with a built-in water system. Here you can take a thick pipe as a basis, then there will be much less welding work.

Attention! All welding seams must be made double, since the temperature in the firebox is not lower than 1000 degrees. If you weld ordinary seams, there is a chance that this place will quickly burn out.

Complete the register drawings in accordance with the dimensions of the stove at home. The layout of the rooms of the house and the arrangement of furniture also need to be taken into account. Here you need to pay attention that it is better to choose a scheme with sheet-metal boilers - they do not have pipe bends connected into one continuous circuit. Building such a structure is not so troublesome. It is also convenient because after installation you can use the hob without any problems, which is not the case with some tube boilers.

When the coolant moves by gravity, you need to raise the expansion tank higher and use larger diameter pipes. If the pipes are of insufficient size, then you cannot do without a pump, since there will not be good circulation.

Boilers equipped with pumps have their pros and cons: you can save money by installing pipes of a smaller diameter and not raising the system so high, but there is one significant disadvantage - when the electricity is turned off or the circulation pump burns out, the heated boiler may simply explode.

It is better to assemble the structure at home, on site, since the device, like individual parts, has a very large weight and dimensions.

System installation

Before installation, a solid foundation is poured, on top of which it is better to lay a layer of brick.
The grate can be laid at different stages: before the boiler, if there is a double structure, the lower part of which can be equal to or higher than the upper part of the grate, when the stove is low and the system is placed a little higher, then the grate, doors, corner on the stove are usually installed after installing the boiler .
The housing is installed - usually it consists of two containers connected to each other by pipes.
The entire heat exchange system is welded to the boiler: the exhaust pipe goes to the expander, goes in a circle, through the radiators, and on the other side the return pipe is welded to the boiler from below.

Stove heating with a water circuit allows, firstly, to use firewood much more rationally, and secondly, to evenly distribute warm air throughout the heated room.

If you decide to make your own heating system at home with a water circuit using wood, think through all the stages of the work, and if you have doubts about the successful outcome, it is better to contact specialists.

Video: Leningrad heating system

Universal gasification and the development of technology, it seemed, should have made stoves obsolete as a means of heating a home. But the high cost of gas supply, equipment and installation gave new life to stove heating.

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There is a lot of firewood in Russia, heating technologies have been significantly modernized. To save money, a reasonable solution is to build a brick stove with a water circuit for heating, with your own hands.

Principle of operation

In addition to the stove, the heating element of the system with a water circuit is a heat exchanger, which is built into the firebox or chimney. The water passing through the register is heated and then enters the pipes and radiators, releasing heat. Due to the temperature difference at the inlet and outlet of the heat exchanger, the liquid circulates in the circuit.

For optimal operation, a circular pump is built into the system, which allows the heated liquid to be more evenly distributed throughout the pipes.

The water circuit must be pressed out and air removed. When water heats up, it increases in volume and to prevent the system from exploding, it is necessary to provide an expansion barrel. When using a closed-type circuit, the reservoir can be located anywhere; in an open system, the expansion barrel is installed as high as possible.

To relieve pressure in the system, it must be equipped with an automatic air vent to release excess gases from the coolant and a safety valve. The devices can be combined into a security complex by including a pressure gauge.

Thus, if you include a long-burning wood-burning brick stove with a water circuit in your home heating system, you can significantly save on heating costs.

Important! The presence of a water circuit must be taken into account at the design stage of the heating system in the house.

Advantages and disadvantages

Designs with a built-in heat exchanger have many advantages:

The system is energy efficient and economical. Brickwork will not require serious financial investments, the costs for pipes and radiators will be in any case, and the heat exchanger is an order of magnitude cheaper than ready-made boilers. When operating a stove, the cost of heating the house will be several thousand rubles for the purchase of firewood for the winter period.
The design of a brick stove hides unsightly elements; if desired, a fireplace or decor can be added to the system.
Heating of the room does not depend on the location of the structure; radiators can be installed anywhere
A brick stove takes a long time to cool down; the water circuit will remain hot for several hours after the wood burns out.

Some publications list the advantages of a water circuit system as the possibility of installing it in a ready-made furnace, which is possible in principle, but in practice this option is associated with a large number of problems that have to be solved.

Disassembling and subsequent reassembly of the stove is the most necessary thing that will have to be done. The cost of correcting an incorrectly installed register is comparable to the cost of a new stove, so contact professionals for such work.

The disadvantage of this design is a continuation of its advantages; in order to make a stove with heat exchangers yourself, you need experience both in laying bricks and in installing heating systems. If experience comes with age and the amount of material studied, then when building a furnace with a water circuit, its disadvantages should be taken into account:

The fireplace is a fire hazard; it is necessary to take measures to prevent fire from reaching flammable objects;
The stove takes up a significant area of the house, design the rooms in advance, include a large heating system in the design of the room;
The temperature near the stove will always be higher than in the rest of the room;
The heating process of the oven cannot be stopped instantly. If you are using a closed loop system with a circulation pump, turning off the electricity (even briefly for a few minutes) and stopping the pump will cause the water in the heat exchanger to boil. To avoid this, provide a combined system for water movement in the circuit.
If the heating system is not used regularly, the water must be drained, which leads to premature wear of the entire structure. Otherwise, the water will freeze, which will lead to the destruction of the entire complex of devices.
You cannot light the stove without water in the circuit. This will lead to the destruction of the register and the reconstruction of the stove in order to use the stove in the summer without “turning on” the battery using the original design of the installation of heat exchangers.
There is a risk of carbon monoxide poisoning, as with all solid fuel heating products, special attention must be paid to the correct manufacture of the chimney.

Making a heating system in your home based on a stove with a heat exchanger and batteries is a cost-effective solution, but the design and construction must be approached competently, taking into account all the nuances of the work.

Stages of work

Creating a heating structure with a water circuit consists of several stages:

System design, determining the location of the furnace, pipes and radiators, calculating the power of the heat exchanger.
Manufacturing (purchase) of a register.
Laying a furnace with simultaneous installation of a heat exchanger.
Installation of the water circuit, including pipes, radiators, security system.
System check.

Let's look at some stages of construction in more detail.

About the heat exchanger

When building a brick stove with a water heating boiler with your own hands, you should take into account many factors and calculate the project as a whole. Any type of materials and structures have their advantages and disadvantages.

There are several ways to install a water register in a furnace:

Depending on the location, choose the material for the heat exchanger and its shape:

Copper - effective due to the high thermal conductivity of the metal, but due to the low melting point of copper, constant circulation of water in the system is necessary;
Steel - heat-resistant steel with a wall thickness of 4-5 mm is used for boilers. For long service life of steel structures, it is not recommended to drain water from them.
Stainless steel is expensive, but the most suitable material for a boiler. The only disadvantages include the complexity of manufacturing.

When choosing the type of material and installation location of the heat exchanger, it is worth remembering that by placing the water circuit in the fireplace, in the summer the entire system will heat up; to avoid this, you will have to remove separate batteries to remove excess heat.

When installing a heat exchanger in the chimney, additional dampers are added to the stove design, which do not heat the boiler during summer operation of the stove. It should be taken into account that the heat exchanger must be larger in volume than when built into the fireplace. In addition, the boiler should not reduce the throughput of the smoke channels.

Calculation of power and dimensions

For normal heating of the room, it is necessary to correctly calculate the register area and its power. For a brick kiln, an approximate calculation is sufficient; it is impossible to make an exact calculation due to many factors and variables.

It is known from practice that heating 10 m2 of space requires 1-1.5 kW of energy. From one square meter of heat exchanger you can get 5-10 kW. To determine the register power more accurately, you need to consider:

Location of the coil in the furnace;
Type of fuel - wood, coal. When burned, wood produces less thermal energy.
Approximate temperature in the hearth and location of the heat exchanger;
Average water temperature throughout the entire circuit;
The heat transfer coefficient of the material from which the coil is made.

As the fuel burns, the power of the heat exchanger will decrease, so it is better to increase the calculated coil area by 10-15%.

Construction of a heating and cooking furnace with a water circuit with your own hands

You can make stove heating in a private house yourself, the main thing is to carefully read the recommendations and carefully and consistently carry out all types of work. First of all, you should choose the appropriate option; the stove can have a hob, fireplace, stove bench and drying rack. It all depends on the size of the room and functionality.

Consumables

To manufacture the structure, excluding the chimney and foundation, you will need:

Solid red brick – 710 pcs.
Fireclay fire-resistant brick – 71 pcs.
Fire door 210x250 – 1 pc.
Blower door 140x250 – 1 pc.
Ash pan door 140x140 – 7 pcs.
Grate 250x300 – 2 pcs.
Cast iron hob 710x410 – 1 pc.
Steel heat exchanger 750x500x350 – 1 pc.
Furnace valve 130x250 – 1 pc.
Gate valve for cooking chamber 130x130 – 1 pc.
Steel strip 50x5x400 – 1 pc., 50x5x980 – 3 pcs.
Steel corner 50x50x980 wall 5 – 2 pcs.
Pre-furnace sheet 500x1000.

Diagram and dimensions of the future furnace

Characteristics of the heating and cooking structure with a register:

Oven dimensions length/width/height 1020x1160x2380mm
Heat exchanger size 750x500x350 mm, material - sheet steel, wall 5 mm inside the hearth, external - 3 mm.
The power of the register is 5.5 kW when laying firewood 2 times a day, which is enough to heat 60 m2, the power can be increased during active operation to 18 kW when using forced circulation, the heated area reaches 200 m2.

Photo of the oven:

Description of the masonry of a furnace with a water circuit

Work must begin with, then prepare the necessary materials, both for the construction of the furnace and for the water circuit system.

Important! The heat exchanger must be pressure tested before installation.

In accordance with the order of the heating furnace with a water circuit, the laying and installation of devices is carried out.

Scheme of laying a furnace with a water heating boiler:

The first row of bricks is laid out; it is important to prevent distortions, both in the horizontal and vertical planes. The masonry should be rectangular, in the future this will affect the entire structure.
The second row begins to form the ash part, a 140x250 blower door is installed.
Third row according to the pattern (repeat).
The fourth row forms the hearth, for which fireclay bricks are used; grooves are made in the bricks to install the grate. The grate is installed with a gap of 5 mm, then the boiler (water circuit) is installed.
The fifth row is placed with a gap of 5-6 mm from the boiler, leaving free space behind the heat exchanger. Two ash pan doors are installed.
The firebox door and the sixth row of bricks are installed, the horizontal and rear channels are separated. For better traction on the fifth row, the channels should be combined.
Rows 7 and 8 are laid out according to the pattern; fireclay bricks are indicated in yellow.
—
On the ninth row, a gap must be left near the exhaust pipe. The two halves of the fireclay brick above the door are cut off. The horizontal channel is divided into two parts. On the same row, ¾ fireclay bricks cut obliquely are installed.
On the tenth row, the bricks are laid perpendicularly, the space above the heat exchanger decreases.
On the eleventh row, the masonry from the ends of the stove is done inward, grooves are made for the hob. Installation of a cast iron hob, the gaps should be 5 mm and a steel corner.
A cooking chamber is formed (row 12).
Row 13 according to the pattern.
On the 14th row, an ash door is installed, the channel increases to its entire length.
Row 15 is similar, taking into account the dressing of the seams.
on the 16th row, the cooking chamber is blocked using a corner and a steel strip 50x5x980.
On the 17th row, the overlap of the cooking chamber is completed.
on the 18th row it is necessary to install two steel strips 50*5*980. Laying as in the diagram.
The 19th row covers the cooking dome, a hole for the hood remains in half a brick, and grooves for the valve are made in the adjacent bricks. A 130x130 valve is installed.
Row 20 is the base of the upper flues; four ash doors are installed at the same time.
The 21st and 22nd rows continue the formation of partitions.
—

The essence of stove heating is the direct heating of rooms by a heat source due to convection and infrared radiation emanating from hot walls. An important condition, which is also the main drawback: the heater must be located in a heated room. This is why homeowners often want to build a furnace with a water circuit connected to remote radiators to heat the entire house evenly. It is worth noting that this issue is not easy and cannot always be resolved. So let's look at different options for putting this idea into practice.

Ways to solve the problem

Obviously, in order to heat the coolant and supply it to the radiator system, the wood stove must be equipped with an additional heat exchanger. There are two ways: purchase a ready-made metal or cast-iron long-burning stove with a built-in water circuit for your home, or make it yourself. We initially follow the second path - we put in work, but save money.

Note. A separate problem is the organization of heating water in a brick oven burning wood and coal. If it has already been built, then redoing the structure can be quite difficult, if not impossible.

There are several types of homemade heat exchangers and options for their installation:

Tank is a boiler built directly into the firebox or into one of the chimney ducts.
A register welded from pipes, sometimes in the form of a coil. It is also placed inside the combustion chamber or in the flue.
Samovar-type heat exchanger (technical name - economizer). It is installed purely on the chimney to extract heat from the exhaust gases.
Full water jacket. In a simplified version, a similar fireplace stove with a water circuit is shown above in the diagram.

Tank-boiler for heating coolant

Reference. The simplest, but not the most effective solution that you can adopt is implemented in some wood-burning sauna stoves. A metal tank with water is mounted on top of the body or suspended from the side if the firebox has a rectangular shape.

The water circuit can be made from the following materials:

black or stainless steel;
cast iron;
copper.

Steel heat exchangers are practical and inexpensive, and therefore the most popular. The price of copper is too high, but the melting point is low, which is why such a structure can “float” when burning coal. As for cast iron, you won’t be able to cast a register from it yourself, unless you install an old MS-140 heating “accordion” into the flue, as shown in the photo. But remember: the battery will instantly burst when cold coolant is supplied to a hot stove or as a result of water freezing during a long period of inactivity.

Pros and cons of various heat exchangers

Installing a tank inside a brick kiln has been practiced by craftsmen for decades. This is a proven and reliable method that allows you to constantly heat water and even organize its natural circulation, you just need to lay large-diameter pipes (about 50 mm) in compliance with the slopes. A properly made boiler tank very rarely burns out, because it contains a large volume of coolant that cools it.

The disadvantage of this option is the large size of the container. It will only fit into a heater made of brick, and there is too little space in metal potbelly stoves. Unlike a tank, the size and shape of a register made of steel pipes can be changed and built into any stove, but other problems arise here:

When installed inside the firebox, the coil is constantly exposed to high temperatures (up to 1000 °C at its peak) and condensation with soot, and therefore will last 4-6 years, after which it will burn out. Stainless or heat-resistant pipes will last longer - up to 10 years.
A more reliable way is to install the water circuit inside the chimney duct, where the temperature is lower. But then the heating intensity will drop and to organize normal heating the heat exchanger will have to be increased in size. It turns out to be a vicious circle.
The coolant circulation inside the register must be non-stop. Otherwise, the water will boil, turn into steam, and its pressure will rupture the pipeline in a weak spot - somewhere at the junction. This means that it is unrealistic to organize gravity flow, and the operation of the circulation pump will have to be secured with an uninterruptible power supply unit in case of a power outage.
The capacity of metal heaters is very limited, so it will not be possible to insert a high-quality heat exchanger there. Practice shows that a steel factory furnace with a water circuit can serve no more than 2 radiators with a total power of up to 4 kW.

Types of welded registers

Important point. Any heat exchangers mounted inside the firebox take a decent portion of the generated heat. This reduces the already low heat output of the stove, plus reduces the burning time from one load of wood or coal.

Economizer (left) and a conventional tank for installation on a chimney (right)

The samovar heat exchanger (economizer) is free from all of the listed disadvantages. It is a water jacket for the chimney and takes away the heat of the exhaust gases. And their temperature in furnaces operating on wood or waste reaches 300 °C. This solution is often used in sauna heaters to heat water for washing. A combined option is a tank through which a chimney pipe is passed.

For obvious reasons, the idea with an economizer cannot be implemented on a brick stove. But for Buleryan, Breneran or another steel potbelly stove, regardless of its size, this option is well suited. And the last, most effective method is to install a water jacket around the heater body. Essentially, it turns any metal stove or fireplace into a heating boiler. One problem is that the option is quite difficult to implement.

Iron stove designed by Butakov with a convection casing and a water circuit on the rear wall of the firebox

Conclusion. The best way to get hot water from a steel heater using wood or exhaust (these are used in garages) is to make a samovar-type heat exchanger or a container on the chimney pipe. For a brick oven there are few options - building in a container or register.

The original design of an external heat exchanger with an improvised economizer is demonstrated in the video:

Calculating register sizes

To make a water circuit for the stove with your own hands, you need to determine its dimensions, or more precisely, the area of the heat exchange surface. To do this, use the following algorithm:

Find out the area of the heated rooms and multiply it by 0.1 kW. If you live in one of the cold northern regions, multiply the square footage of the premises by 0.2 kW. For a house of 100 m² you will need 10 and 20 kW of thermal energy, respectively.
From practical observations it follows that a register installed directly into the firebox is capable of transferring up to 10 kW of heat to the coolant from each square meter of its surface. Divide the heat requirement by this figure to get the radiator area.
For an economizer and a tank mounted in a chimney duct, where the temperature is lower, take the specific heat transfer value not 10, but 6 kW per 1 m² of surface.
Knowing the area, the dimensions of a rectangular container are easy to calculate. But the length of the pipes from which the register is welded is calculated by the formula: L = S / πD (S – area, D – pipe diameter).

Diagram of a brick oven with a hot water boiler placed in the firebox

Note. When calculating the heated area, you do not need to take all 100 or 200 square meters of the house; subtract from them the rooms that the stove heats directly.

If we take a dacha room with an area of 100 m² as an example, then the heat exchange surface of the radiator built into the firebox should be at least 1 m². When installed in a flue, this area will increase to 10 / 6 = 1.67 m².

We build the tank into a brick oven

The first and important rule: it is necessary to plan the installation of the water circuit even before building a brick heater. It is almost impossible to remake a finished structure; you will have to disassemble at least half of it again. This applies to all purely heating stoves - Russian, Dutch and Swedish, which do not have a hob.

In this case, the register is mounted in the smoke circuit of the stove, and not in the firebox

Reference. If you have a heating and cooking stove at home or in your country house, then it is sometimes possible to remake it. Lift the cast iron surface with the burners and evaluate whether it is possible to place a boiler under it and what shape to give it. Be sure to consult with a master stove maker.

We offer the option of a simple stove with a heating boiler installed in the path of combustion products, but outside the firebox. Thanks to this, the tank is made of metal 3 mm thick, which is enough for long and reliable operation. Schematically the unit looks like this:

Advice. If you choose another design, where the container is mounted in the firebox, then make its walls facing the flame from metal 5 mm thick, the rest - 3 mm. To make the register, use pipes with a wall thickness of 3.5 mm, and when installing, do not connect it to the walls of the stove, since metal and brick have different expansion coefficients.

The procedure for laying the hob

The laying of a furnace with a water circuit located in the combustion chamber is described in the following video:

Making a contour for a steel stove

To make a samovar-type heat exchanger for a chimney, select 2 pipes: one in diameter should be equal to the size of the stove pipe, and the second should be 3-4 cm larger (for example, 102 and 133 mm).

Homemade samovar-type heat exchanger

Determine the heat transfer area as described in the previous section, then cut both pipes to the calculated size.
Make 2 holes 20-30 mm in the water jacket casing and weld the supply and return pipes with threads to them.
Insert one pipe into another and weld together, making jumpers from a steel strip. From it, make the upper and lower covers for a homemade water circuit.
Check the unit for leaks and install it on the chimney as close as possible to the oil or wood stove. More details about production are shown in the video.

Unlike internal water circuits, the economizer can be easily connected to various heating systems - with forced and natural circulation of coolant. In the second case, it is important to slope the lines 2 mm per 1 m of pipe and install an open expansion tank at the top point.

Conclusion

It is not easy to judge how useful a homemade stove with a water circuit is in operation. According to user reviews, such units work flawlessly in small country houses and garages. We must also take into account the fact that the craftsman who made the heater with his own hands will not criticize it, but will try to find positive aspects. One thing is clear: there are cost savings when all rooms of the building are heated evenly. But in houses with an area of over 100 m², it is worth considering installing a solid fuel boiler.

Design engineer with more than 8 years of experience in construction.
Graduated from the East Ukrainian National University. Vladimir Dal with a degree in Electronics Industry Equipment in 2011.