To obtain a consistently high crop of vegetables throughout the year, any greenhouse will have to be equipped with a suitable heating system that will provide the plants with the temperature they need. The simplest and relatively cheapest option are long-burning furnaces, because in some situations they turn out to be more effective than modern electrical products. How such boilers are arranged, and which models are worth paying attention to, you will learn more about this below.
Furnace Feature
A long-burning furnace is a modern heating equipment capable of maintaining high temperature indicators in a room for a long time on a single fuel tab. At the same time, the plant efficiency is almost 90%, which is largely explained not by the fast burning of the fuel used, but by its slow decay, which results in the formation of “gas for heating” (with time it transforms into thermal energy).
Coal briquettes, sunflower husks, sawdust, peat and even household waste are used as fuel, but more often standard material is used - firewood. On average, one such furnace on a full tab can function normally for at least 12 hours, maintaining stable high temperature indicators in the room.
Principle of operation
When organizing furnace heating for a greenhouse or greenhouse, you should first pay attention to the presence of a vestibule, an effective ventilation and gas exhaust system in the existing building. The working principle of finished stoves may vary depending on the type of construction.
But in general, the processes taking place inside are as follows:
- Cold air flows through the pipe of the upper part of the furnace, supplemented by a damper.
- The lower compartment is filled with fuel and set on fire as much as possible, but since the flow of oxygen to it is limited, chips or firewood smolder more than they actually burn.
Important! In addition to heating the airspace of the greenhouse, such a furnace, when a water circuit is connected to it, will provide heating of the irrigation fluid.
Types of furnaces from the manufacturer
Having a desire and a small set of materials, a long-burning furnace can be built independently, and quickly and cheaply. However, for those who do not want to burden themselves with such worries, there is a ready-made solution - a purchased product, with all the necessary design features. In the modern market there are several devices suitable for the greenhouse, so before making your choice, it is worth evaluating the capabilities of each of them.
"Vologda"
The model is characterized by high heat transfer rates, even if the laying of firewood will be performed only 2 times a day. The efficiency of Vologda reaches 80%, and the principle of operation resembles the activity of a gas generator: the coolant is supplied using flexible hoses that are simultaneously connected to the back of the boiler and the fuel tank.
It will take at least 40 minutes to heat the liquid in an existing water tank to 60 degrees. Some models can simultaneously heat not only the greenhouse, but also a residential building, where the heat is supplied by means of water heating radiators and corresponding circuits.
Buleryan
A variant of a heating device that is rarely used to heat the greenhouse space, but like other varieties, is able to maintain long burning of the fuel used. "Buleryan" - a convection product, when working with which wood products or ordinary firewood are used.
Important! In specialized heating equipment stores, you can find different types of Butakov’s stove, so if you need to heat a polycarbonate greenhouse, you should choose the Gymnasist or Student model, with a power of 5 or 9 kW.
In appearance, the design resembles a barrel laid to one side, with tubes attached along the length. Depending on the parameters, devices of different capacities are distinguished: for example, the smallest models pass at least 5 cubic meters of air every minute.
So that the incandescent case does not become dangerous for humans, the manufacturer covers it with special paint, which is one of the advantages of the Buleryan furnace. Among the disadvantages of the product, it is worth highlighting the absence of a temperature controller, the need for constant monitoring and certain difficulties in the installation process.
Butakov's stove
Another convection type unit, which is a direct competitor to the previous product. It was developed in the 1960s and is still used for space heating. The efficiency of such a furnace is about 85%, which is quite enough for continuous heating of a structure with an area of 150 m². Unlike Buleryan, it can also be used for cooking, and temperature indicators are kept at the right level without the constant addition of firewood.
Did you know? The first boilers for heating the premises were cast iron and often combined with brickwork. The history of district heating began in 1716 and is associated with the name of Martin Trivald, who developed a steam-based system.
Outwardly, the Butakov’s furnace resembles a parallelepiped, with convection air exhaust pipes inside, a special two-chamber firebox, and a grate to protect the bottom from burnout and even distribution of combustion over the entire installation area.
Among the remaining structural components of the product, a chimney, a damper and an ash pan are distinguished. Almost the only drawback of the described construction is the exit from the body of numerous tubes, which makes the installation inconvenient to maintain.
Slobozhanka
Outwardly, “Slobozhanka” is more reminiscent of a standard potbelly stove, though with three different units: a gas generator, the stove itself and a heater. The principle of operation of the device is based on the thermal decomposition of compounds of organic and inorganic origin, with the release of combustible gases.
Did you know? The first heating systems appeared in ancient Rome and were a kind of mine, which was located under the homes of wealthy people and was heated with wood. The air in the room was heated by heating the floor.
However, if in other designs they are brought out together with the exhaust, then here they play the role of an additional heat source, increasing the efficiency of the entire installation. Fuel materials (mainly solid) are loaded into the combustion chamber from above, therefore, the process itself occurs in a downward direction.
Based on the specific design of Slobozhanka, there are three ways to supply the air required for the combustion process - through:
- Pipe opening from top to bottom (L-shaped feed).
- A pipe located in the center of the device (air enters from below).
- Side pipe at the very bottom of the furnace.
When choosing a specific polycarbonate greenhouse furnace, always consider the following criteria:
- the size of the device, on which the size of the area heated by it depends;
- fuel used (the cheaper the raw materials, the more profitable the furnace, however, we must take into account other important factors: for example, the unpleasant odor that appears when burning waste);
- fuel consumption and heat transfer level;
- the ability to control temperature (the presence of a temperature controller in the furnace);
- complexity of installation and further maintenance of the stove.
How to make a stove for a greenhouse with your own hands?
Almost any furnace for heating the greenhouse space consists of a fuel compartment, a second bottom (located above the indicated compartment), an opening with a door and a blower. In addition, we must not forget about the organization of the chimney (must have a metal valve and cover). Chips, sawdust and small firewood are more often used as fuel; therefore, we suggest considering a home-made version of such a stove.
Preparatory work
To design a long-burning furnace, in the simplest version, the following tools and materials will be required:
- sealed barrel, the volume of which is 200 l;
- a thick metal circle (with a diameter slightly smaller than the barrel);
- 4 corners or the same amount of channel, slightly shorter than the pancake radius;
- a piece of metal pipe for blowing with a diameter of 100 mm (length above the barrel by 5 cm);
- a piece of metal pipe for a chimney with a diameter of 150 mm and a length of 5 m;
- welding machine;
- Bulgarian;
- sledgehammer;
- chisel;
- pliers;
- hammer.
In the finished form, the furnace on sawdust or small wood should look something like this:
As an alternative, you can build a brick and metal pipe stove in the greenhouse, but in this case, most of the heat will not come from the walls of the structure, but from the metal chimney, so the longer it is, the more air will warm up. However, a too long horizontal chimney limits the traction in it, so it is not recommended to use a part longer than 6 m.
The finished brick oven will look something like this:
All that is needed for its manufacture is a brick, vertical and horizontal pieces of pipe of the right size, supports, cement and tools for assembling the structure. However, if you want a mobile, easily collapsible design, then it's easier to use an old barrel.
Sequencing
A home-made long-burning furnace is an economical version of a factory design, which often has a large working resource. However, you can achieve the most positive results from its work only if you design it correctly.
Therefore, we propose to consider the sequence of steps for manufacturing the simplest, "barrel" system for heating:
- Take the barrel prepared in advance, cut off the weld seam at its upper end part and align the sharp ends with pliers. As a result, you get a cylinder with a cap.
- Bend the edges of the cylinder inward with a sledgehammer, and the remaining side, on the contrary, leave it outside.
- Turn the cover over and put it on the prepared cylinder, only so that it fits tightly on it and does not slip.
- Using a chisel, carefully cut a hole with a diameter of 102 mm in the center of the lid (later an inflatable tube will be inserted into it, which should freely move up and down).
- In the upper part of the future furnace, outline a hole for the chimney and cut it out (a part of the chimney will be welded to it, no more than 30 cm long).
- When the installation case is almost ready, you can deal with the air supply device. To increase the rigidity of the pancake previously obtained, it is advisable to bend its edges, but if you use a part of another barrel as a lid, then you must weld the existing cork hole.
- Weld corners or channels on the inside of the lid, and install a damper in the upper part of the pipe hole (it is better to fix it with the wing nut, by loosening or tightening it you can adjust the amount of air supplied.
- Install a chimney made of a pipe with a diameter of at least 150 mm, otherwise the smoke from the firewood will not be fully discharged outside. To ensure good traction, the length of the chimney should be at least 5 m.
- In addition to the device already manufactured, you can weld a ball valve that is suitable for draining accumulated condensate from the inside of the unit.
- The ignition site should be at the bottom of the barrel, so cut a rectangular hole in it and make a drawer or tray to clean the stove from unburned firewood. Above the door level, install a hole partition with a hole in its central part (it should correspond to the lower end of the blowing pipe).
Video: how to make a do-it-yourself oven for a greenhouse
What is the difference between a homemade stove from a purchased one?
At first glance, a home-made long-burning stove differs from the purchase price only, but in fact, everything is more complicated. In the factory models, everything is thought out to the smallest detail, so if you do not have experience in this field, it is better not to take the risk and purchase the finished product. So you protect yourself from possible burnout of metal, poor draft of the chimney and other unpleasant problems that will only complicate the operation of the finished furnace.
Moreover, improvised parts are not always highly compatible, so you should not rely on the fact that different elements of a home-made device will be able to dock well. However, if you have already prepared the necessary tools and materials, and also have experience in welding, it is worth trying to make a stove yourself, especially since using the scheme of the finished product, there will be no difficulties with the invention of a fireplace for working off.
