Air Conditioning

Air conditioning is the invention of mechanical engineers. Ben Franklin experimented with alcohol and freezing water in 1758, and it took another 144 years before modern air conditioning was invented. It took mechanical engineers another 50 years to make a design cheap enough for the middle class.

Impact:

Air conditioning has been an enormously powerful invention which has spurred economic development and productivity for entire geographic regions. The economic empires based out of Florida, California, Brazil, Texas, Malaysia, Singapore, Hong Kong and more all owe their success to this one invention. Air conditioning makes life bearable and increases human productivity in areas that have humid heat problems. Interestingly if you look at global population distribution and urbanization over the last 100 years you can see the shift from far northern and far southern climates (Germany, Nederlands, Argentina, New England, Japan) to southern climates (Brazil, SE Asia, Southern China, Southern India).

How it Works:

Air conditioners are heat pumps which use a fluorinated hydrocarbon to to transfer heat from inside to outside. See our page on refrigerators to see how heat pumps work.

Video: good explanation of the concept of physics in air conditioning
Video: Auto Air Condition Systems
Video: 3d graphics showing layout of auto air conditioning system

Beginnings:

Early innovators discovered that some volatile materials like ammonia evaporate faster than water, and this can freeze water. Early experiments involved compressing and condensing these materials. Willis Carrier invented a device that blows air over cold tubing in 1902. By 1906 – the term ‘air conditioning’ was used by Stuart Cramer who invents a device that humidifies the air.

In 1931 single room air conditioners were only available to the wealthy and cost over $120,000. During the 30s and 40s movie theaters had air conditioning while normal residences did not, during the hottest days of summer people would watch more movies in order to escape the heat.

Over the years air conditioning has become obtainable by the middle class. ASME (American Society of Mechanical Engineers) members rated air conditioning as one of the top 10 ten inventions of all time.

Further Reading:

Global Cooling and the History of Air Conditioning – by the ASME >
Willis Carrier – from Carrier Inc >
Full history >

Related Topics:

Sources:
Popular Mechanics
Slate.com
ASME
Carrier

Photos/Video:
Edison Tech Center / Minerals Education Coalition
Whelan Communications

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