The Roots Of Air Conditioning
As far as we can look back into ancient history, we find people who were devising ingenious ways to cool their homes in the summertime. The Egyptians, Persians, Romans, and Chinese are all known to have found some sort of means (usually employing water evaporation and air movement) to create central air conditioning. However, to trace the roots of modern air conditioning, we must first look at the development of refrigeration.
It’s interesting that the roots of modern mechanical refrigeration go as far back as the 1700s and chemical experiments by the Scotsman, William Cullen. This was followed by the work of the American inventor and statesman, Benjamin Franklin. And in the early 1800s, the Englishman, Michael Faraday, started his experiments and established some of the basic laws of refrigeration.
It was an American who was living in Great Britain at the time, Jacob Perkins, who obtained the first patent for a vapor-compression refrigeration system (in 1834). Perkins built a prototype system and it actually worked, but it didn’t prove to be a commercial success.
It was in 1842 that an American physician, John Gorrie, designed the first system for refrigerating water to produce ice. He also conceived the idea of using his refrigeration system to cool air for comfort in homes and hospitals. His system employed an air compressor, and then water was used to cool the hot compressed air before it was re-expanded, which provided the cooling. Gorrie built a working prototype, but his system was also a commercial failure.
Alexander Twining began experimenting with vapor-compression refrigeration in 1848 and he obtained patents in 1850 and 1853. He is the one who is credited with having initiated commercial refrigeration in the United States around 1856.
Thereafter, the most prominent uses for commercial refrigeration were for the production of beer, to commercially produce ice, and then to chill meat in the Chicago stock yards.
However, to carry us into the realm of modern refrigeration and air conditioning, we must first consider the ground-breaking work of the Serbian-American genius, Nikola Tesla. Tesla’s patents and theoretical work formed the basis of modern alternating current (AC) electric power systems (including the three-phase system of electrical distribution), and the AC motor, with which he helped usher in the Second Industrial Revolution. So, he not only created the electrical power, but he was also the inventor of single- and three-phase fans.
And this brings us to the person who is known as the father of modern air conditioning, Willis Carrier. The first large-scale electrical air conditioning system was invented by him in 1902, which employed an imported centrifugal compressor.
And although he did in fact invent and install the first true mechanical air-conditioning system, just as important as this is his study of the properties of chilled air and his development of the modern psychometric chart, whereby the comfort properties of conditioned air can be defined and controlled.
However, one of the last great innovations to bring air conditioning into common commercial and household use was the invention of non-flammable and non-toxic refrigerants in the late 1920s.
The CFC, R-12, was invented by Thomas Midgley Jr., who worked for Dayton Engineering Labs (a division of GM’s Delco) under the direction of Charles Kettering. This development (along with the later introduction of the HCFC R-22) was truly a welcome breakthrough, for without it, air conditioners and domestic refrigerators would not be considered “safe.”
There have been many other important developments in the evolution of modern HVAC/R systems which I will discuss in future articles.