A century later, 'Apparatus for Cooling Air' becomes indispensable contrivance

In the summer of 1902, a 25-year-old engineer named Willis Haviland Carrier was presented with a challenge by a Brooklyn printing plant owner.

Fluctuations in summertime heat and humidity had caused the dimensions of printing paper to keep altering slightly, enough to ensure the misalignment of colored inks. Could Carrier come up with a way to stabilize temperature and moisture in the air inside the printing plant?

Yes, Carrier managed to stop the bleeding ink 100 years ago. He later received a patent for his "Apparatus for Cooling Air," and the presence of mechanically cooled air led to a shift in the power centers of the world's economy, including the rise of the U.S. South. Air conditioning made it possible for printers, chocolate manufacturers and silicon chip makers to manufacture their products in a consistent, quality-controlled environment, and in an atmosphere that brought workers comfort and improved productivity,

Carrier didn't invent the system for providing mechanically cooled air - but the company he formed developed the technology and did much to improve it and bring it into the world's homes and businesses during the 20th Century.

Physician-scientist John Gorrie of Florida could arguably lay claim to the title, "father of air conditioning." He was convinced that he could improve the health of malaria victims if he could lower the temperature of their hospital. He was quite a mechanical tinkerer, and predicted that portable cooling systems could also effectively be used to transport fruits, meats and vegetables long distances.

According to a history compiled by the American Society of Heating, Refrigerating and Air-Conditioning Engineers Journal, "Without question Willis Carrier was one of the great men in the history of air conditioning, but he was born 28 years after John Gorrie wrote in the Apalachia Commercial Advertiser (in 1848), 'If air were highly compressed, it would heat up by the energy of compression. If this compressed air were run through metal pipes cooled with water, and if this air cooled to the water temperature was expanded down to atmospheric pressure again, very low temperatures could be obtained, even low enough to freeze water in pans in a refrigerator box."

He received a patent in 1851 for "the first machine ever to be used for mechanical refrigeration and air conditioning." Although the mechanism produced ice in quantities, leakage and irregular performance sometimes impaired its operation. Gorrie went to New Orleans in search of venture capital to market the device, but either problems in product demand and operation, or the opposition of the ice lobby, discouraged backers. He never realized any return from his invention.

Research and tinkering in mechanical air cooling advanced somewhat during the next half-century.

By 1900, the ability to install mechanical cooling was well established in the food industry, but the technology hadn't yet been adapted into the ability to effectively cool entire rooms or buildings and make the occupants consistently comfortable.

At the turn of the century, many cooling engineers settled on a forced-air design for cooling buildings - after all, the "plenum" system of blowing forced-air over a steam or water-heated surface to distribute heat had been used effectively for the last 50 years.

But settling on a method to cool the air, size the equipment, and remove moisture from the air proved vexing.

Through trial and error, engineers started to come up with a series of formulas to determine the temperature to which the air must be cooled to remove a given weight of moisture, the amount of latent heat that must be removed, and the surface area of the cooling coil.

A solution was close, predicted the editors of the trade journal Ice and Refrigeration in 1904. "The practical application of mechanical refrigeration to air cooling for the purposes of personal comfort, no doubt has a field…and the day is at hand, or soon will be, when the modern office building, factory, church, theatre and even residence will be incomplete without a mechanical air cooling plant."

Bringing it all together was Carrier. In 1911, he disclosed his basic Rational Psychrometric Formulae to the American Society of Mechanical Engineers. The formula still stands today as the basis for all fundamental calculations for the air conditioning industry.

In 1921, Carrier patented the centrifugal refrigeration machine. The "centrifugal chiller" was the first practical method of air conditioning large spaces. Previous refrigeration machines used reciprocating-compressors (piston-driven) to pump refrigerant (often toxic and flammable ammonia) throughout the system. Carrier designed a centrifugal-compressor similar to the centrifugal turning-blades of a water pump. The result was a safer and more efficient chiller.

Industries flourished with the new ability to control the temperature and humidity levels during and after production. Film, tobacco, processed meats, medical capsules, textiles and other products acquired significant improvements in quality with air conditioning.

Cooling for human comfort, rather than industrial need, began in 1924, when three centrifugal chillers were installed in the first department store in the nation, the J.L. Hudson building in Detroit. Cooling was introduced on the first three floors, and then eventually to the entire building. The boom in human cooling spread from the department stores to the movie theaters, most notably the Rivoli theater in New York, whose summer film business skyrocketed when it heavily advertised the cool comfort.

By 1930, more than 300 theatres nationwide displayed on their marquees, "Cooled by Refrigeration."

In 1928, Carrier developed the first residential "Weathermaker," an air conditioner for private home use. The Great Depression and then World War II slowed the non-industrial use of air conditioning. After the war, consumer sales started to grow again.

After World War II, mechanical cooling allowed the development of the modern glass-walled skyscraper - the symbol of freedom from traditional construction systems as well as heating and cooling methods. Glass-walled skyscrapers such as the United Nations (1952) linked modern architecture with the new technology.

At first, air-conditioning systems were designed with initial cost as a major consideration. Operating costs were virtually ignored because electrical energy was cheap - but that changed for good during rapid energy price increases during the 1970s, which brought a shift in emphasis toward energy-efficient operation. The rest is history, cool and comfortable history.

A turn-of-the-century engineer who worked on the New York Stock Exchange's cooling system, Alfred Wolff, had it about right.

"If the refrigerating plant is instituted…and the entering air is cooled…and the percentage of moisture lowered, the result will be that this room will be superior in atmospheric conditions to anything that exists elsewhere. It will mark a new era in the comforts of habitation."

Information for this article was excerpted from American Heritage Magazine, the American Society of Heating, Refrigerating and Air Conditioning Engineers Journal, the National Building Museum and information provided by Carrier Corp. 

SHOWN HERE IS the world's first centrifugal chiller, circa 1922. Most chiller pumps in use at the time used piston-driven rotating impellers to move refrigerant, but there were limits to their capacity. Willis Carrier's design utilized a smooth, efficient centrifugal compressor, which finally made it possible to cool large spaces.