On this date… 17 July 1902
Modern Air Conditioning Invented
Thanks to Tesla’s ability to harness AC electricity in a safe, reasonable manner, the world has air conditioning (A/C, not to be confused with the AC of alternating current electricity). In the depths of summer, where heat stroke kills thousands of people each year, A/C is a modern convenience that literally saves lives, keeps us comfortable, and ironically contributes to global climate change (sometimes called global warming). Air conditioning revolutionized the world, created a whole industry (HVAC – heating, venting, and air conditioning) that employs thousands of people, and was invented, in its modern form, on this date, 17 July 1902.
The idea of cooling people and places goes back to ancient times. What, you think the people of ancient Persia or Greece liked sweating in blistering, mind-numbing heat? But due to their technological limitations and geography, their only real alternative was to import ice or snow from far afield. The practicalities of this, not to mention cost, were astronomical, so ancient, and modern, people suffered. At least until an engineer named Willis Carrier designed a machine that we now take for granted.
A recent engeinner graduate of Cornell University, Carrier began working for the Buffalo Forge Company in 1902. There he was tasked with solving a problem where humidity was warping and wrinkling magazine pages. After running numerous experiments Carrier designed a system that controlled humidity using cooling coils that would either humidify (by heating water) or dehumidify (by cooling water) air. Though it was big, bulky, and expensive, the general idea of modern air conditioning units was created. With a group of other engineers, Carrier formed his own company, the Carrier Engineering Corporation, in 1915.
Refrigeration Technology
The general public first gained exposure to the concept at the 1904 World’s Fair in St. Louis, Missouri, where organizers used Carrier’s mechanical refrigeration idea to cool a 1000 seat auditorium. It wasn’t until the 1920s that air conditioning began gaining widespread use, most often in movie theaters, where customers flocked to see major stars on the silver screen. Even these early versions were still plagued with problems, as the auditoriums were usually cooled through vents in the floor, which resulted in frigid temperatures at lower levels but hot, muggy conditions at the higher levels. In 1922, Carrier Engineering installed the first well-designed cooling system for theaters at the Metropolitan Theater in Los Angeles. This pumped cool air through higher vents for better humidity control and comfort throughout the building. Later that year, at the Rivoli Theater in New York Carrier publicly debuted a new type of system that had fewer moving parts and was more reliable, which helped lower the costs and expand air conditioning throughout the country.
Refrigeration technology in general was improving at a rapid rate during the early part of the 20th century. The earliest modern refrigerators were invented in 1913, began getting mass produced by 1918, and became widespread around the US by 1927. Frigidaire, GE, and even General Motors all created their own versions of small cooling devices. Unfortunately, the Great Depression and World War II kept most people from being able to afford or use them. Only after WWII had engineers made small window units affordable to the average consumer. In 1947 almost 50,000 window units were sold, and by the late 1960s most new homes had central air conditioning. According to the Energy Department, A/C is now available in 87 percent of all American households, or nearly 100 million American homes.
Energy Use and Other Technology
Indeed, A/C isn’t just a household item. Through it factories were able to better protect workers and increase efficiency, allowing everything from baked goods to wartime supplies and more. Cooling theaters via air conditioning led directly to summer blockbusters, and the ability to precisely control temperature in a space also helped make shopping malls, transatlantic flight, and computer servers that power the internet possible.
All these uses need energy, though. Almost half of all US energy consumption is used for heating and cooling, which contributes to a growing need for fuel and leads to climate change. It’s a vicious cycle. If it feels hot outside, it likely is. The remedy is to cool off using air conditioning, which only makes it hotter outside, upping the need for the A/C. Hopefully new technologies can reduce energy use and make A/C more efficient, which might help offset all the damage to the planet and keep future generations alive and well.