Before air conditioning, Americans endured the discomfort of summer as best they could. Awnings, window screens, shade trees, and high ceilings (to let the hottest air rise above people's heads) all helped. And mechanical fans--powered by kerosene, alcohol, gas, electricity, even flowing water--at least moved the air around.
Cooling the air in a building mechanically is far more difficult than warming it. You have to extract heat; you cannot add cold. The first U.S. patent for a device that could be used to cool air was granted to John Gorrie in 1851 (Patent No. 8,080). It lowered temperatures by compressing air and then permitting it to expand rapidly. Heat was forced from the air and exhausted during compression, but was drawn from the surroundings as the air expanded. Because Gorrie's machine was essentially a heat extractor, it could chill water, food, or the air around it. His innovation went no further than a prototype, however, due to the loss of his financial backer and the lack of public interest in the device.
The first successful mechanical refrigeration equipment was patented soon after the Civil War, but the process was economical only on a grand scale. It was used mainly in brewing, food processing, textile manufacture, and cold storage. The lethal substances ammonia and sulfur dioxide were the primary refrigerants, and the equipment was totally unsuitable for homes. Practical domestic refrigeration machines and "safe" refrigerants such as Freon did not appear until the 1930s.
It is important to understand that air conditioning is not just chilled air, but the result of a careful balance between temperature, humidity, supply and exhaust, air cleanliness, and air movement. Willis Haviland Carrier (1876-1950) was one of the first people to recognize this relationship and devise a mechanical air-conditioning system to regulate simultaneously each of these components. One of the critical elements in the system was the centrifugal compressor, which Carrier began manufacturing in 1922. In 1924, Carrier sold his original compressor to the Onondaga Pottery Company of Syracuse, NY, for the air conditioning of its lithography plant. The machine remained there until about 1957, when the Carrier company repurchased the compressor for donation to the Smithsonian. By that time, the company had sold more than 7,500 of the large machines worldwide.
Willis Haviland Carrier
Willis Haviland Carrier (1876-1950) was born and reared on a family farm outside the town of Angola in western New York. The mechanical aptitude he demonstrated on the farm led him to pursue a bachelor's degree in mechanical engineering at Cornell University, where he graduated in 1901. Carrier began his professional career with the Buffalo Forge Company, which manufactured blowers, exhausters, and heaters. He immediately began collecting data needed to improve the design of heating and ventilating systems, and his systematic approach led company officials to place him in charge of its newly created department of experimental engineering.
Carrier gained wide recognition in 1902, when he headed up Buffalo Forge's contract with the Sackett-Wilhelms Lithographing and Publishing Company to control humidity in its Brooklyn, NY, plant. The plant had suffered chronic problems because the frequent fluctuations in atmospheric conditions caused its paper stock to expand or contract as the humidity varied, thereby making the proper registration of colors in the printing process nearly impossible. The air-conditioning system Carrier devised successfully maintained the relative humidity at 55 percent throughout the year, with temperatures held constant at 70 degrees Fahrenheit in the winter and 80 degrees Fahrenheit in the summer. Carrier's system increased the humidity in the winter by introducing low-pressure steam from the plant's boiler, and dehumidified the air in summer by passing the air over coils that were cooled with water refrigerated by an ammonia-compression machine.
Carrier followed the success of this system with the development of improved temperature and humidity controls and air distribution systems. (Carrier eventually received 80 U.S. patents.) His work opened up a whole new industry, as businesses of various kinds started purchasing air-conditioning systems from the Buffalo Forge Company. Having installed systems in cotton, worsted, and silk mills, a shoe factory, and a pharmaceutical plant by 1907, Buffalo Forge established a wholly owned subsidiary, the Carrier Air Conditioning Company of America, in that year. During the next six years, Carrier air-conditioning systems were in use in nearly 200 industrial processes, including paper mills, meat-packing houses, breweries, bakeries, food processing, and industries producing cloth, candy, soap, leather, rubber, glue, and cigars.
When Buffalo Forge decided to abandon the air-conditioning business in 1915, Carrier and six associates formed the Carrier Engineering corporation. With Carrier as president, the company soon prospered. Its big advancement came in 1922, when Carrier introduced a radically new and more efficient refrigerating machine, the centrifugal compressor (U.S. Patent Nos. 1,575,817-18019). The earlier refrigerating machines had been large, complicated, and dangerous (to the extent that the refrigerants--typically ammonia or sulfur dioxide--were toxic and posed a threat if they escaped). The costs of maintaining and operating these early machines, combined with the toxic nature of their refrigerants, had restricted their use to industrial processes. The new centrifugal compressor required far less space, was cheaper to operate, and utilized a safe, nontoxic refrigerant (dielene, which was a cleaning compound found to have suitable properties as a refrigerant; it was, however, expensive), thereby making practical the use of mechanical air-conditioning systems for human comfort.
Carrier's new centrifugal refrigeration compressor provided the foundation for safer, smaller, and more powerful large-scale air-conditioning systems. It paved the way for air conditioning to be used for the benefit of people (in theaters, department stores, hospitals, banks, offices, and hotels; Carrier introduced its first central air-conditioning system for homes in 1952), as opposed to the betterment of industrial production (which had been the main users of mechanical air conditioning prior to the 1920s).
The Carrier company built its first practical commercial centrifugal refrigeration compressor in 1922, where it operated experimentally in the company's Newark, NJ, offices. The first demonstration of the compressor took place in May 22, 1922, in Carrier's Newark offices before the invited members of the American Society of Refrigeration Engineers. Two years later, Carrier sold his original compressor to the Onondaga Pottery Company of Syracuse, NY, for the air conditioning of its lithography plant. The machine remained there until about 1957, when the Carrier company repurchased the compressor for donation to the Smithsonian. By that time, the company had sold more than 7,500 of the large machines worldwide.
In 1924, the Carrier company installed centrifugal refrigeration machines in the J.L. Hudson department store in Detroit and the Palace Theater in Dallas, thereby introducing the phrase "air conditioning" into the public vocabulary. In 1928, the Milam Building in San Antonio, TX, became the first completely air conditioned office buildings.