[Ar.Niyati Gupta]

The main purpose of commercial HVAC (heating, ventilating, and air conditioning) systems is to provide the people working inside buildings with "conditioned" air so that they will have a comfortable and safe work environment. "Conditioned" air means that air is clean and odor-free, and the temperature, humidity, and movement of the air are within certain comfort ranges.

HVAC systems control the air temperature, of course, but also to intake outside air, exhaust or filter contaminated air and efficiently use energy.

http://www.edcmag.com/articles/hvac-syst...-they-work