ttps:////»https://www.w3.org/TR/REC-html40/loose.dtd»>
The principle is exactly the same as the refrigerator: a substance capable of cooling a serpentine set inside the device – something like a system of hoses through which liquid or gas passes. In the case of air conditioning, this substance – based on chlorine, fluorine and carbon – is called R-22. This product leaves the liquid state and turns into a gas at a very low temperature: only 7 ºC, against, for example, the 100 ºC that water needs to evaporate. The cold R-22 runs through a circuit of coils, condensers and evaporators, absorbing the heat from the air sucked in from the internal environment. What the most diverse models of air conditioning have not yet managed to eliminate is an annoying side effect: dry air. “In contact with the cold, the humidity in the air condenses into droplets inside the air conditioner, as it happens in a bottle of cold beer”, says engineer Maurício Carvalho, who works at a company that manufactures air conditioners in São Paulo.
Device uses special substance to cool the air1. The ambient air is sucked in by a fan (A) and passes through an evaporator, passing around a coil filled with R-22, a refrigerating substance at a temperature of 7 ºC and in a liquid state. In contact with the icy coil, the air cools down and returns to the room (B)
2. By absorbing the heat from the air, the R-22 changes state inside the coil and turns into a gas, then entering an electric compressor. This piece, which produces the noise of the air conditioner, compresses the R-22 until, under high pressure, it becomes a hot gas at 52ºC
3. This gas enters another coil, outside the device, called a condenser. Hotter than the outside environment (C), R-22 cools down a bit. With that, it turns liquid again even before reaching 7°C, as it is under high pressure. Another fan blows the leftover warm air into the street (D)
4. The R-22 (in a liquid state because of the high pressure) enters an expansion valve, a kind of orifice where the liquid quickly loses pressure and cools down to 7ºC, which keeps it in a liquid state. From there, the cycle starts all over again.