Significance of humidifier in AHU

Humidification is often necessary in colder climates where continuous heating will make the air drier, resulting in uncomfortable air quality and increased  static electricity. 

Various types of humidification may be used

Evaporative

dry air blown over a reservoir will evaporate some of the water. The rate of evaporation can be increased by spraying the water onto baffles in the air stream. 

Vaporizer

steam or vapor from a boiler is blown directly into the air stream. 

Spray mist

water is diffused either by a nozzle or other mechanical means into fine droplets and carried by the air. 

Ultrasonic

A tray of fresh water in the airstream is excited by an ultrasonic device forming a fog or water mist. 

Wetted medium

A fine fibrous medium in the airstream is kept moist with fresh water from a header pipe with a series of small outlets. As the air passes through the medium it entrains the water in fine droplets. This type of humidifier can quickly clog if the primary air filtration is not maintained in good order.