Greenhouse heating, its types and features, the device of heating systems of various types. Heating a greenhouse is providing a closed room with a comfortable microclimate for full-fledged cultivation of plant crops in it. We will tell you about this important function for a greenhouse in our article.
Types and features of greenhouse heating
When developing a project for a home greenhouse, it is necessary to pay attention to the choice of its heating system. It should be the most appropriate and optimal for a particular case. This will play an important role in the future in obtaining an early harvest.
Modern technologies involve three types of heating for such structures:
- Natural heating - in this case, the greenhouse's protected ground absorbs the heat of daylight;
- Biological heating of the greenhouse - occurs due to the decomposition of manure or other organic matter, which is accompanied by the release of heat;
- Technical heating - carried out by burning fuel, using electric heaters or hot water.
The implementation of any of them contributes to maintaining a favorable microclimate in the greenhouse - creating the desired daily temperature and humidity. When choosing a heating system, you need to take into account their features. The budget options include natural and biological heating.
Natural heating by the sun is based on creating a greenhouse effect in a structure made of transparent materials. Passing through such a covering, the sun heats the soil and building elements. Those, in turn, giving off heat, gradually heat up the air in the structure, if it is reliable and hermetically sealed.
Since solar activity is not constant, the goal of a naturally heated greenhouse owner should be to keep the heated air in the building as efficiently as possible. This can be achieved by correctly orienting the structure in relation to the cardinal points and using additional methods for storing solar heat, which include the manufacture of water panels or solar ovens.
The most primitive version of such batteries, which are often used by summer residents, are plastic bottles filled with water. During the day, they heat up in the sun, and at night they give off heat, leveling the temperature drop, which is undesirable for plants.
Natural heating of the greenhouse, although it is the cheapest and most environmentally friendly, is limited in use due to the lack of sun in the northern regions and the middle zone of our country.
Biological heating is based on the chemical activity of substances of organic origin. These include sawdust, horse manure, household food waste. During decomposition, these biological materials come into contact with air, which acts as an activator of exothermic reactions accompanied by the release of heat. The amount of such energy can be enough to constantly warm up the greenhouse, even in winter.
Biological fuel can be vegetable humus. To prepare it, a five percent urea solution is added to a wooden container with grass, the container is closed with a wooden lid and the mixture is kept for two weeks.
Technical heating will be especially interesting for those who plan to harvest the whole year. When it's cold, this heating complements natural heating perfectly. It can be solid fuel, water, infrared, gas and electric.
When building a greenhouse with artificial heating, the following must be considered:
- The air in such a room should not be very dry, otherwise the upper part of the plants will inevitably wither;
- The release of heat should go from bottom to top gradually, so that it stays in the greenhouse longer;
- Heating should not promote the development of bacteria;
- Heating control should be simple.
Greenhouse heating systems
If there is a part of the heating main under the land plot, then we can say that you are in luck. It remains only to find its location and install a greenhouse there - the problem with heating will be solved. In other cases, you will have to arrange heating the greenhouse with your own hands. We'll talk about this below.
Gas heating
For gas heating large buildings, a line of burners is used, evenly distributed along its perimeter and connected to the gasification of the house. For a small greenhouse, you can stock up on gas cylinders. Winter heating works for several weeks, so in this case, a pair of cylinders will last for a long time.
It is important to remember that the product of gas combustion is carbon dioxide, which is essential for plant life. However, if carbon dioxide is in excess, the opposite effect can be obtained. Therefore, to remove combustion products, the greenhouse should be equipped with exhaust ventilation so that the supply of fresh air is constant.
Lack of oxygen can disrupt the combustion process and lead to the release of fuel into the air. To prevent this from happening, it is recommended to use heaters with protection: special sensors will turn off the gas supply when required.
Electric heating
Heating with electricity is a cheaper option. It can be organized using heaters that include paddle fans and built-in thermostats. They greatly facilitate the use of such devices and allow you to provide the required temperature in a short time.
Using fans is not the only way. Another common heating method is cable heating of the soil, which works according to the "warm floor" principle. Its main advantage is the saving of the inner space of the greenhouse, the reason for this is the underground laying of the heating cable. Its location contributes to the effective heating of the soil, and then the air. Due to the possibility of regulating the temperature regime of the cable using such a system, it is possible to select the heating of the greenhouse in accordance with a certain stage in the development of crops. In addition, the cable heating thermostat helps reduce energy costs and simplifies heating control.
Other advantages of such greenhouse heating include:
- An increase in the varieties of cultivated plants up to the subtropical flora, which is very demanding on the thermal regime;
- Independence of the created microclimate from weather conditions;
- Acceleration of growth, increase in yield, extension of the time of fruiting of crops.
The installation process of such heating is completely simple:
- The installation of a cable heating system should begin with the installation of a heat-insulating substrate; moisture-resistant insulation - foam, for example, can serve as a material for it.
- After that, the thermal insulation must be covered with plastic wrap and a layer of sand with a thickness of at least 100 mm should be poured on top.
- A heating cable should be laid on a sand cushion in the form of a coil with a pitch of 150 mm and covered with a layer of sand, but of a smaller thickness - 50 mm.
- To protect against external damage, the installed heating system must be covered with a netting from above, and then everything must be covered with a layer of fertile soil. Its thickness should be 35-40 cm.
Water heating
In material terms, such heating is quite profitable, especially if you do it yourself. Of the basic materials, you will need several old pipes, an electric heating element (TEN) and a welding machine as the main equipment.
The work should be done step by step:
- Before heating the greenhouse, a V = 50 liter boiler with heating elements with a capacity of 2 kW should be mounted in its corner. When heated, water will rise up the riser to the expansion tank, and then be supplied to the system. A metal boiler is made from a section of a wide pipe, to which a bottom equipped with a flange must be welded.
- The heating elements should be connected with an electric cable with a plug and securely insulated.
- A rubber gasket must be inserted between the flange and the boiler drum.
- It is required to make a thirty-liter expansion tank from a metal pipe. From the side of its bottom and ends, it is necessary to weld couplings designed to connect to the heating system and the riser.
- Cut out a hole in the expansion tank for adding water. Its level will need to be monitored constantly.
- It is necessary to cut threads on both sides of each pipe, and then connect all products into registers. The pipes should be placed at the edges of the greenhouse with a downward slope.
- The boiler body must be grounded with a three-core copper cable without insulation. The wire must withstand voltage over 500V. Two cores of the cable must be fixed on the phase contacts of the heating element, the third - on the body of the heating boiler.
To automate such a system, you can include an AC relay and a temperature sensor. After it is triggered, the relay contacts will close, and the heater will heat the water and raise the temperature in the greenhouse. After the liquid reaches the preset level, the device will work again, open the relay circuit, and the heater will turn off.
Solid fuel heating
It is used in private, industrial and farm applications. It is especially popular in rural areas - there is often an abundance of firewood. A large selection of boilers designed for burning solid fuels is offered at specialized retail outlets. Such installations are affordable, do not require an installation permit and are characterized by good efficiency.
However, solid fuel heating has some disadvantages: complex control, the combustion process is directly related to the quality of the fuel and needs to be controlled.
With a lack of money for a finished heating system, solid fuel heating can be done in the greenhouse with your own hands. Sometimes this solution is very successful. A homemade stove with a horizontal chimney is extremely simple to manufacture.
The step-by-step process of its installation looks like this:
- In the greenhouse vestibule, you need to make a brick stove with a firebox.
- A chimney should be laid along the length of the greenhouse. On the other side of the building, it must be taken outside so that carbon monoxide is removed, and the heat remains inside.
- The distance between the end of the building and the firebox is taken at least 25 cm, and from the rack to the top of the horizontal chimney - a little more than 15 cm.
Infrared heating
The device in the greenhouse infrared heating allows you to significantly reduce the cost of electricity and most evenly distribute the heated air inside the room. Other advantages of such a system include a 30% increase in seed germination, durability of at least 10 years, ease of transportation and installation.
An element of such heating can be a special conductive film or a light bulb fixed in a ceramic base. Heat sources should be located around the perimeter of the greenhouse.
Preferring infrared heating, it is important to know that, unlike convection heating, it does not affect the air, but the surrounding objects, which subsequently radiate thermal energy into the inner space of the greenhouse. This heating method is best suited for polycarbonate-coated structures.
Summing up, it can be noted that the main purpose of organizing greenhouse heating is to provide an optimal microclimate, most suitable in terms of humidity and temperature for high crop yields in the cold season. To solve the question of how to heat a greenhouse, an integrated approach is needed, implying the choice of a durable system that works in two directions - heating the air and warming the soil.
How to heat a greenhouse - watch the video:
For the question considered in this context, the most optimal variant is cable heating, which simultaneously provides both of the above-mentioned directions.
