The air-condition or the AC, the electrical appliance that is practically used just about everywhere from houses, offices, vehicles and many other places to tackle the sveltering heat has a father. An American engineer by the name of Willis Carrier, who while working at the Sackett-Wilhelms Lithographing & Publishing Company, a printing plant in Brooklyn, New York came up with a rather unique solution to a quality problem experienced at the firm.

Willis Carrier
Picture for representational purposes

Carrier used his knowledge of heating objects with steam and reversed it by sending water through cold coils (filled with cold water) instead of hot coils, which cooled the air thereby enabling the amount of moisture to be controlled. This made the humidity in the room controllable, and it helped maintain consistent paper dimensions and ink alignment.

Willis Carrier was granted a patent on his invention on January 2 1906, four years after his invention of the air-conditioner. He termed his creation, 'Appartus for Treating Air.' Career is believed to have made the world's first spray-type air-conditioning equipment, which humidified or dehumidified air, heating water for the first and cooling it for the second.

Willis Carrier. Pic/YouTube
Willis Carrier. Pic/YouTube

After discovering that "constant dew-point depression provided practically constant relative humidity," Willis Carrier designed an automatic control system, for which he filed a patent claim on May 17, 1907. This later became known among air conditioning engineers as the "law of constant dew-point depression."

Willis Carrier's "Rational Psychrometric Formulae" tied together the concepts of relative humidity, absolute humidity, and dew-point temperature thus enabling the design of air-conditioning systems to precisely fit the requirements at hand. Carrier presented it at the American Society of Mechanical Engineers in December 3, 1911 and it went on to become the "Magna Carta of Psychrometrics."

Willis Carrier poses next to his invention. Pic/YouTube
Willis Carrier poses next to his invention. Pic/YouTube

Carrier along with seven young engineers pooled together their life savings to form the Carrier Engineering Corporation in New York on June 26, 1915 after their employer Buffalo Forge Company decided to confine its activities entirely to manufacturing on the onset of the First World War. The Carrier Corporation pioneered the design and manufacture of refrigeration machines to cool large spaces. Residential air-conditioning was introduced in the 1920s. The Carrier Corporation remains a world leader in commercial and residential HVAC and refrigeration. In 2007, the Carrier Corporation had sales of more than $15 billion and employed some 45,000 people.