Buleryan oven and convection ovens

Recommendation points

• What is this Buleryan oven
• The design and principle of operation of Buleryan furnaces
• Buleryan stoves – pros and cons
• Which convection oven is better – Buleryan, Breneran or Professor Butakov’s oven
• Several recommendations for buyers and owners of convection ovens

In this article: how the Buleryan oven works and works; its negative and positive characteristics; which stove is better – Buleryan, Breneran or Professor Butakov; recommendations for buyers and owners of convection ovens.

A house somewhere in a rural wilderness, near a pretty pond or even a river, is an idyll, a pacifying rest for the nerves. Dream, in a word. But what about heating a dream house? Especially if you want to visit it periodically at any time of the year … Traditional heating options disappear – there is no natural gas, electricity is intermittent. Stove heating remains, and only stove heating, without water heating, since periodic draining and re-filling of the system with coolant is not a rest, but a routine. Not a bad option with a stove stove, but there is a better way out – a convection oven, for example, the Buleryan oven.

What is this Buleryan oven

Air has a lower heat capacity than any liquid, therefore, by heating the air, you can quickly heat the room. Any household stove heats the air and the efficiency of its heating depends on the size of the stove – the larger it is, the faster the air heats up, because there is a larger heat transfer area.

The first Buleryan stove was not created by heating specialists – ordinary lumberjacks in the Rocky Mountains of Canada. Cold climates, hard work in deforestation – lumberjacks needed an efficient stove capable of heating the air in their huts as quickly as possible in order to keep warm and dry their clothes after work. By the way, the authorship of Canadian lumberjacks can be clearly traced in any Buleryan stove and the like – these stoves run only on wood fuel. The name of the furnace and the patent for it do not belong to any Canadian manufacturer at all – they are owned by Energetec GmbH, a company from Germany. In Russia, under the license of a German manufacturer, a furnace similar to Buleryan is produced under the brand name “Breneran”, produced by CJSC “Laotherm”.

Externally, the Buleryan stove is similar to a conventional potbelly stove, but compared to the latter, it has great capabilities in heating the air, realizing heat exchange in three ways – radiation, convection and heat transfer. In their design, the buleryans combine three devices at once – the furnace itself, the heater and the gas generator.

The design and principle of operation of Buleryan furnaces

An oval barrel-shaped steel body, a two-tier firebox through which 7 air pipes bent in the middle to the center of the firebox are vertically led. Outside there is an oven door, an air regulator and a smoke damper, the usual tray for ash removal is absent.

The original design of Buleryan-type furnaces solves the problem of air injection for heating without the use of electric fans – convection is provided by the temperature difference at the point of entry and exit of air from the pipes passing through the furnace of these furnaces. The air temperature directly at the outlet of the air pipes during the operation of the furnace reaches 110-120 ° C (do not check with your hand, you can get burned!), The smallest Buleryan (model “Kid”) pumps through itself and heats up more than 4 m³ air per minute.

Buleryan furnace design: 1 – ash pan; 2 – primary chamber; 3 – injector; 4 – a blower with an adjustable damper; 5 – partition; 6 – secondary chamber; 7 – loading door; 8 – chimney pipe with a regulator; 9 – heat exchange tubes

Glowing wood fuel in the first (lower) combustion chamber forms a generator gas – combustible and capable of providing additional thermal energy when it is burned. True, for its formation, it is required to burn exclusively dry wood and for complete combustion, conditions are necessary that Buleryan is only partially able to provide (for complete combustion of generator gases, air supply under pressure, a special catalyst and a much higher temperature than Buleryan are required).

The Buleryan-type furnace has two operating modes: kindling, during which the operating temperature is reached inside the furnace, and the air in the heated room quickly warms up to the optimal level; gasification, the stove is switched to this mode after about half an hour from the start of kindling and after the end of rapid heating of the cold room. To switch to gasification mode, the Buleryan firebox is filled with firewood to capacity, the door is closed and the opening angle of the dampers is adjusted to reduce the amount of air entering the firebox. As a result, the wood fuel does not burn with an open flame, but smolders, the air temperature at the outlet from the air pipes drops to 55-60 ° C. One full load of firewood in the Buleryan stove is enough for 10-12 hours of heating.

Buleryan stoves – pros and cons

Positive characteristics of the Buleryan furnace:

• Provides fast convective heating of the room, heated air can be transported through air ducts to rooms on different floors.
• Heating of premises occurs evenly.
• Less fuel consumption, no complicated maintenance, easy to install and operate.
• The efficiency of Buleryan furnaces is about 70%.
• Long period of operation on one full fuel load (10-12 hours).

Negative characteristics:

• The Buleryan stove and its analogues operate only on solid wood fuel.
• Even 70% of the generator gas is not burned, a significant part of it escapes into the pipe.
• Mandatory need for an insulated (this is important!) Pipe, regardless of whether it is metal or brick.
• The need for a significant allocation of space for placement. Horizontally – at least a meter from the furnace body to any wall or objects, for this reason, such furnaces are most often installed somewhere in the middle of the room. To reduce the distance fivefold, it is necessary to install metal sheets on the walls with a height slightly higher than the furnace installation height.
• Dust burning is inevitable, since some parts of the Buleryan furnaces will heat up to temperatures above 120 ° C.
• It is possible to achieve the fuel economy declared by the manufacturers and the robots for a long period of time from one bookmark of firewood is possible only by fine-tuning the position of the dampers installed in the blower and pipe, and this is not so difficult.
• Due to incomplete combustion of fuel, the pipes of Buleryan-type furnaces smoke in any weather – for this reason, manufacturers strongly advise to bring them to a height of at least 3 meters from the upper edge of the furnace.

A serious problem with any Buleryan type stoves is condensation in the chimney that forms during the operation of the stove. It consists of tar, soot and water, and its appearance and accumulation is caused by the fact that the furnace gases at the outlet have a low temperature, and the combustion of the fuel does not take place completely. Condensation accumulations are especially noticeable at the joints on the pipe, when the condensate heats up, especially when the furnace is fired up after a long period of inactivity, an unpleasant odor is formed that penetrates into the living quarters.

Which convection oven is better – Buleryan, Breneran or Professor Butakov’s oven

First of all, the stoves under the Buleryan and Breneran brands are identical in design, they are produced only – one in Germany, the second in Russia (under license), so there is no particular difference in them.

Furnace Breneran and Buleryan are identical in design

Professor Butakov’s furnace works on the same principle as the Buleryan furnace, but it has structural differences: a larger number and slightly larger cross-section of air pipes, they are completely hidden in the furnace body and air intake in them is performed at right angles; the body is made in the form of a parallelepiped (which, according to the creators, contributes to better combustion of the generator gas); the chimney pipe is introduced in the upper plane, and not at the end, as in the Buleryan stove; there is a drawer for ash, grate.

Of the above design differences, the Butakov stoves are the most inconvenient: the chimney entry point – changing the position of the damper, it is easy to burn yourself on the hot base of the pipe or on the upper part of the stove body; the rotary damper of the blower is not equipped with any lock and when you try to set its position, it moves independently under the weight of the handle.

Furnace design “Professor Butakov”: 1 – pull-out ash drawer; 2 – grate; 3 – cold air inlet; 4 – firebox; 5 – furnace door; 6 – convective pipes; 7 – hot air outlet; 8 – surface for heating food; 9 – gate and place for fixing the chimney

The grate, present in Butakov’s stove, is for some reason considered an advantage by the manufacturer – but in the case of convection ovens, the better burning of firewood, which is provided by the grate, is not an advantage, because the fuel will have to be loaded more often. By the way, in the Buleryan and Breneran stoves, firewood burns almost completely and with a minimum residue, although these stoves are not equipped with grates. The oven manufacturer Butakova claims that its flat top allows you to heat food – but the temperature of the body of such ovens is relatively low and it turns out that the food will have to be reheated for a long time. It will be appropriate to note here that the temperature of the body of the working furnace of Professor Butakov is higher than that of the working furnace Buleryan – the air pipes built into the body do not give a shielding effect, as in Buleryan, which means that its hot body can get burned and it will last a shorter period of time, because . no heat dissipation from side walls.

It is worth mentioning that in convection ovens of domestic production, small and large imperfections are very often found – either the seams glow at night, or some structural elements are missing. In German Buleryany, no such imperfections were noted.

Prices for convection ovens: the smallest models Buleryan and Breneran (per 100 m³) cost about 11,000 rubles, the cost of Butakov’s “Gymnazist” oven, also designed for 100 m³, about 9 500 rubles.

Several recommendations for buyers and owners of convection ovens

Especially carefully choose the place of installation of the convection oven; in the absence of heat shields, this will require more space than you expect. The safest would be to install such a stove in a separate room, preferably a basement, with good ventilation in case of reverse draft in the chimney. Consider the exit of the pipe, its sealing when exiting through the roof. I repeat – the insulation of the chimney is absolutely necessary for such furnaces.!

For better smoldering in a convection oven, it is better to deviate from the recommendations of the manufacturers and lay the fuel according to the following scheme: chips and thin logs are laid in the first layer, there should be small voids with air between them; on top, with an emphasis on the back wall of the firebox, large logs are laid out, a little free space must be left between the logs and the firebox door; put pieces of newspaper, tree bark, wood chips and small branches in this free space, put thicker logs on top (for coals). After placing the fuel in the firebox according to the above diagram, light the paper and close the firebox door, not forgetting to open the damper in the chimney (gate) and the blower damper before that. As the firewood burns up, put the stove in smoldering mode, reducing the opening angle of the dampers.

Important! In order to reduce condensation deposits on the walls of the chimney, convection ovens should be heated only with absolutely dry wood..

A protective heat shield can be purchased ready-made, or you can make it yourself, and without using a layer of insulation recommended by the manufacturer behind it. We take a sheet of metal and attach it to the wall so that a small gap of about 50 mm remains between it and the wall – the main thing is that this gap is the same over the entire area of ​​the metal sheet. The radiation of the furnace will heat the metal screen and a constant air movement is formed in the space between it and the wall, in the direction from the floor to the ceiling, which will take heat from the heat screen, the wall behind it will not heat up.

Which model of the convection oven is better to choose – with a blank firebox door or with glass installed in it? Firstly, stoves with glass in the door will cost the buyer 70-80% more, and secondly, it will not work for a long time to admire the tongues of flame in the stove through the window in the door, since the glass will certainly get smoked, and it will also be possible to sit in front of the stove not easy – strong radiation of heat will not allow.

Like stoves of other designs, the Buleryan stove is not as ideal as the manufacturers claim – it is important to understand this and take into account its shortcomings even before buying.