July 18, 2011

Working of an Air Conditioner

Hi Guys,

This time let us see How an Air Conditioner works.

Basically Air Conditioner works on the principle of Thermodynamics Second Law (Kelvin Planck’s statement). It states that ‘Heat cannot be transferred from a cold body to a hot body without the help of external energy’. AC and Refrigerator works on same principle. The size and the level of cooling vary.

Generally many people think that hot air is sucked in. But actually hot air is sucked in and is again sent into the room as cold air. This occurs till the desired temperature is achieved.

Generally Freon gas is used as refrigerant (but now these days liquid ammonia is used as a substitute as Freon is a main source of Global Warming). This gas is sent through a series of ducts where it absorbs the hot air. Then it passes through evaporator where it is expanded and the temperature decreases. This cool air is transferred in another set of ducts and cool air is sent in. Generally ACs also includes humidifying or dehumidifying units and therefore the environment remains ambient.

There are basically two types of ACs, the olden day Window ACs and the modern day Split ACs. In Window ACs all the components are kept inside the same box and it is suitable to be fitted in a window.

In Split ACs, the cold side (evaporator or expansion valve) is kept inside the room. The hot side (compressor) is kept on the outer side and a tube connects both the units.

This is quite a simple passage. I don’t want to bring in technical details here. If you wish to know more in detail and how the capacity of an AC to be used is determined, please visit How Stuff Works- AC website.

Happy Reading!!!


  1. Thanks, thats very knowledgeable.

  2. Very informative article Karthick... These things are so normal that we take it for granted, never know how it works...
    Have a fabulous week ahead:)

  3. You hit it right on the nail. Awesome diagram and clear description!


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