The main task of any heating system is to maintain a predetermined sufficiently high temperature indoors. At the same time, the ambient temperature (street) can vary significantly depending on the geographical location and season. And the heater must compensate for weather heat losses, which certainly occur when the temperature difference occurs due to the influx of cold air from the street and the outflow of warm air from the room and through the elements of the building. You can heat a room in several different ways. There are at least three main types of heating systems that differ in heating methods:
- Systems that heat by supplying warm air: stationary (water and electric) and portable (electric) fan heaters; thermal curtains (water and electric); air heating systems (gas, water and electric).
- Convection systems, which include: convectors (water and electric), convector-type radiators. Convection is the process of mixing air flows, which occurs due to the different density of warm and cold air (cold air is heavier).
- Systems that transfer heat using radiation (infrared systems): fireplaces and stoves, lamps, underfloor heating, halogen infrared heaters.
Consider the principles of operation of the most common types of heaters.
The principle of operation of the oil cooler
The oil heater has a metal case, inside of which heating elements are located. They are filled with special oil, which, after heating, keeps heat for a long time, since it has a large heat capacity.
Due to the mixing of warm and cold air flows, the air heated by the oil radiator is distributed throughout the room. The intensity and speed of heating the room primarily depends on the power of the radiator, although its design also plays a role. To increase the efficiency of the radiator, sometimes a fan is connected to it, the operation of which contributes to the rapid heating and mixing of air.
The principle of operation of the fan heater
The operation of a fan heater is based on a heating element (ceramic plates and a spiral), through which the fan blows air. Thus, the air in the room is heated by the fan heater very quickly. The desired degree of air heating can be adjusted thanks to the power regulator.
Many fan heaters have an antifreeze device. With minimal energy consumption, it automatically maintains the room temperature at +5°C and thus prevents freezing.
The safest and most convenient fan heaters with a heating element in the form of ceramic plates. These plates do not get very hot, and this, first of all, prevents unnecessary «burning» of oxygen in the room, and also increases their service life.
The principle of operation of an infrared heater
Infrared heaters differ from most other heaters by the very principle of their operation — they do not heat the air, but objects. Initially, the thermal energy emitted by an infrared heater is absorbed by the surfaces surrounding the heater: furniture, walls, floors, etc. Thus, they heat up and then give off heat to the air.
Like ordinary light, thermal radiation cannot be absorbed by air. Therefore, without any loss, all the energy of the infrared heater reaches people and all heated surfaces in the area of its action. Thanks to this, it is possible to equalize the air temperature along the vertical of the room locally in a certain place and reduce the average temperature in the entire room, because a person will feel the necessary heat, absorbing energy directly from the infrared heater.
The principle of operation of the heat gun
Powerful fan heaters are called electric heat guns. Among their distinguishing features is a fairly strong body, well protected from various damages. Therefore, the principle of operation of heat guns is the same as that of fan heaters — they heat the room with a stream of warm air. There are also heat guns that run on diesel fuel and gas — with a chimney and direct heating.
A chimney gun, from which combustion products are removed, has a closed combustion chamber with an exhaust pipe. In it, fuel is supplied by a pump through a heated filter to the nozzle, and in the same place, in the combustion chamber, the fuel is sprayed and ignited. The fan, which is located in the rear end of the gun, pumps air into it. Through the rear holes, part of the air enters the combustion chamber and supports the combustion process of the fuel there. The main part of the air is heated due to the fact that it passes between the walls of the combustion chamber and the outer casing of the gun.
Thus, the products of combustion do not enter the heated room, but are removed through the chimney. Due to this, this type of guns can be used to heat enclosed spaces with people. Although in such rooms sufficient ventilation must be additionally provided, which can compensate for the loss of air that is used in the combustion process.
A fuel tank is built into the direct heating heat gun. The fuel from it enters a heated sump filter, and from it — through a compressor or pump — into the nozzle. Air is blown into the combustion chamber by a fan located at the rear end of the gun, into which fuel is sprayed from the nozzle. The fuel is ignited by an electrical spark gap or spark plug. A special screen does not allow the flame to leave the combustion chamber. Hot air is supplied to the heated volume together with combustion products. Such a gun can only be used in open areas or in large rooms with an excellent ventilation system and in the absence of people.
The principle of operation of the thermal curtain
Strictly speaking, a thermal air curtain is not a heater. In fact, this is an energy-saving device. The task of such air curtains is to clearly delimit zones with different temperatures on both sides of open gates, entrance doors or working windows.
The thermal air curtain looks like an elongated fan heater that produces a powerful and narrowly directed «flat» air flow. It is installed above a window or doorway or to the side of it.
The air curtain prevents unwanted air flow by creating a barrier in the open doorway for cold air to enter the room. In this case, there must be a sufficiently high speed of the air flow, which is created by the air curtain, so that the air reaches the floor itself. In this case, the main part of the air is blown into the room, but some part is invariably thrown out into the street. Warm air remains inside the room, and the cold outside air is cut off by the flow created by the air curtain.
Sometimes air curtains are used for the opposite purpose — to keep the cold in a special room. Such curtains do not heat the air, but simply create a powerful air flow that closes the opening and separates the premises into different temperature regimes.