The encyclopedia · Engineering & Operations · Product decision · 1902-1920s
Willis Carrier made air conditioning by controlling humidity, not just temperature
Carrier's 1902 'apparatus for treating air' fixed a printing plant by cycling air over cold coils to hold humidity at 55%.
Buffalo Forge · Carrier Corporation
the move
The Sackett & Wilhelms Lithographing and Printing Company in Brooklyn printed in colour by running the same paper through four colors, and if the humidity changed between runs the paper expanded or contracted and the colors misaligned. They needed moisture control, not cooler air for people.
Willis Carrier, a young engineer at Buffalo Forge, designed a system that circulated air over coils chilled by compressed ammonia, bringing the air below its dew point so it lost moisture and holding humidity near 55%.
The invention was decisive for printing accuracy, and Buffalo Forge sold it wherever humidity was a problem, such as flour mills and to Gillette, where moisture rusted razor blades. By 1906 Carrier was exploring the comfort applications that turned air conditioning into a consumer industry.
why it works
- Printing precision depends on controlling the water in the air, and dew-point control is the precise lever for that.
- Cooling air to the dew point removes moisture, which was the real process problem.
- A device that solved a production problem had demand wherever humidity was a hazard.
- The same technology later could be aimed at human comfort, not just industrial processes.
what transfers
The cause of a problem may not be the obvious one: a humidity complaint is a water-in-the-air problem, and solving it precisely can open a whole new market the direct approach misses.
what came after
Carrier went on to found Carrier Engineering (later Carrier Corporation), and air conditioning spread from industrial humidity control to theatres, offices and homes, enabling the summer movie season and the growth of the Sun Belt and shopping malls.
references
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