Everything Everywhere Daily: History, Science, Geography & More - Air Conditioning

Starting point is 00:00:00 One of the biggest problems that humanity has faced for thousands of years is heat. Excessive heat made it difficult to work in the middle of the day. Heat was especially problematic in the tropics where a shockingly large percentage of humanity lived. As cities became more developed, excess heat all year round became a limiting factor in how tall buildings could get. All of these problems were solved with one invention. Learn more about air conditioning and how it helped us usher in the modern world on this episode of Everything everywhere daily. What if your perceptions about the past were wrong? ThruLine is a podcast that takes you back in time to uncover the parts of the story that may have gone unnoticed. It effectively

Starting point is 00:00:56 turned day into night and how it shaped the world now. Time travel with us every week on the ThruLine podcast from NPR. Heating and cooling are flip sides of the same coin, yet they're very different in how you go about doing it. Heating is relatively simple. You take something and burn it, and you will produce heat. And if that is impossible, we produce heat ourselves, and we can keep ourselves warm by just trapping that heat through insulation. Cooling, however, is totally different. Cooling, or getting rid of heat energy, is much more difficult. Traditionally, the options you had for keeping cool were more limited. People would often just shield themselves from the direct rays of the sun. They might wear long, loose clothing to keep the warmer air temperature away from

Starting point is 00:01:49 their body, or they might wear wide-brimmed hats to keep the sun off them. Their buildings might be made of thick walls to keep the inside cool and to keep the outside heat away. Many cultures also worked around it by avoiding the hottest times of the day. In Spain and in other cultures, they just shut things down in the middle of the day to avoid the heat. People would leave the fields and their businesses and go home, have an extended lunch, and wait for the sun to get lower in the sky. Most of these things involve simply avoiding the heat and keeping the sun off of you. It's not a bad strategy, but it's also not quite the same thing as burning wood to produce heat. However, there is a physical process that can remove heat from a system and cool it down. Evaporation. You've probably

Starting point is 00:02:36 experienced this yourself. If you get wet, the water drying on your skin will cool you down. This is why you can cool off by swimming in water even if the water happens to be kind of warm. For thousands of years, people around the world have used evaporation to cool themselves down. In ancient Egypt, people would hang wet reeds in the windows. The evaporation of the water from the reeds cooled the air as it passed through the window. In Persia, they used a system that was different but relied on the same fundamental principles. They created tall towers with openings known as wind catchers that face the prevailing winds and captured and directed airflow into buildings. The air would then pass over a pool of water or some wet surface,

Starting point is 00:03:18 cooling it down as it entered living spaces. This technique is actually being revived in modern buildings that use passive cooling as a way to lower temperatures, but without any electricity. During the Islamic Golden Age, many buildings featured central courtyards with fountains or pools. These water features cooled the surrounding air through evaporations, and the courtyards provided shaded cool spaces. Before I get any further into the discussion of air conditioning, I should explain why evaporation reduces temperatures, because this ancient technique is critical to understanding

Starting point is 00:03:50 how modern air conditioners work. As you know, matter can be in different states, particularly solid liquid or gas. Heating or cooling something can cause it to undergo a phase change, causing it to melt, freeze, or boil. However, it is possible for something to be a gas at the same temperature as a liquid and a solid. That's because when you measure the temperature of something, you're actually measuring the average of the kinetic velocity of all the molecules

Starting point is 00:04:16 that make up the system. But not all of the molecules in a glass of water, for example, have the same amount of energy. When a water molecule evaporates, it absorbs heat from its surroundings. This energy is used to break the molecular bonds that hold the water molecules together in the liquid state, allowing them to escape into the air as vapor. Because energy is taken out of the air, the air gets cooler. This principle of using the evaporation of substances to cool something down was used in the 18th and 19th centuries to conduct experiments such as liquefying gases. To reach very cold temperatures, they would often use a cascade of cooling one gas to cool another gas and so on. This physical phenomenon was used to create the first refrigeration systems.

Starting point is 00:05:00 The very first mechanical refrigeration system was built in 1834 by an American vendor living in Britain named Jacob Perkins. His refrigeration system and all subsequent systems use a liquid called a refrigerant which has a very low boiling point. Early refrigerants use liquids such as ammonia, sulfur dioxide, methyl chloride or propane. When these liquids in a closed loop underwent a phase transition, they took heat out of the system, just like via evaporation. The system that Perkins designed was not the first air conditioner because air conditioning isn't just refrigeration. It also has to do with the conditioning part of air conditioning, which has to do with humidity, not temperature. Hot weather is one thing, but hot weather with high humidity is particularly

Starting point is 00:05:50 annoying. Humidity was what the first air conditioner was actually invented to solve. The development of the first air conditioner is usually credited to Willis Carrier. Carrier was working for the the Buffalo Forge company in 1902 when one of their clients had a problem. The second Wilhelm's lithographic and publishing company in Brooklyn, New York, had an issue with their paper. When they were doing four-color printing, they had to run the paper through their presses four times, and the paper had to be perfectly aligned. The problem was that humidity caused the paper to change its width and sometimes crinkle, which would ruin the printing process. Carrier developed a system where air would be blown over coils with cooled water inside. moisture in the air would condense on the cooled coils, resulting in cooled air with the moisture removed.

Starting point is 00:06:42 The system worked, and many people commented that it felt more comfortable to be working around the machine. Carrier put two and two together and created the Carrier Company, one of the largest air conditioning companies in the world today. The term air conditioning was actually coined in 1906 by Stuart Kramer, who ran a textile mill in North Carolina. was trying to add humidity to the air in his factory to make the textiles easier to handle. Carrier liked the name that Kramer used and adopted it for his company. Air conditioning did not catch on right away. The early systems were expensive and bulky, and they required electricity, which still wasn't ubiquitous in the very early 20th century. The first home to be air conditioned was built in Minneapolis in 1914, 12 years after the invention

Starting point is 00:07:30 of air conditioning. The system was massive, requiring a separate room in the the house for the equipment, and it isn't even known if the system was ever used, as the owner of the home died a year before it was completed. In 1922, Carrier developed the centrifugal refrigeration compressor. It allowed for air conditioning systems that were smaller and cheaper with fewer moving parts. One of the first places to adopt this new system was the Rivoli Theater in New York City in May of 1920s. Movie theaters proved to be eager early adopters of air conditioning. They could easily adapt the duckwork of their heating systems for air conditioning, and air conditioning systems could lure in customers. During hot summers, many people would buy a ticket to a movie, not because they were

Starting point is 00:08:13 interested in the film, but because they wanted to spend an hour or two away from hot and humid weather. The concept of a summer blockbuster is entirely due to air conditioning. The first air conditioner that could fit into a window was invented in 1931. The system is very similar to the window units that many people around the world use today. However, these first windowed air conditioning systems were extremely expensive. A single unit cost between $10,000 and $50,000 1932. And if that would be converted into modern dollars, the price would be somewhere between $200,000 and a million. As of the 1930s, residential air conditioning was still just for the wealthy. In 1933, the first air conditioning system for automobiles was released. And in 1935, Chrysler was the first major auto producer

Starting point is 00:09:04 to offer it in its vehicles. However, it was still extremely expensive and didn't sell well. Home air conditioners didn't become commonplace until after the Second World War. In 1945, Life magazine ran a four-page spread on air conditioning titled, quote, air conditioning. After the war, it will be cheap enough to put in private homes. Their prediction would turn out to be true. 1947, 43,000 cheap window air conditioning units were sold, which exploded over the next several decades. By the early 1960s, central air conditioning systems were being installed in homes that cooled the entire building and didn't require bulky, ugly units sticking out of windows. As air conditioning became affordable and commonplace in all public spaces, it began to change

Starting point is 00:09:52 major societal and cultural patterns. Communities in deserts or very hot climates usually didn't have large populations. Suddenly, it became possible for someone to live in such an area and not have to suffer from living in the heat. Communities such as Phoenix, Arizona, or Las Vegas, Nevada exploded in population after the rise of air conditioning. Air conditioning also helped in the development of skyscrapers. In a recent episode, I covered the history of skyscrapers and the technical innovations that made them possible. And one of the important developments that I didn't mention in that episode was air conditioning. Very tall buildings can't allow windows to be opened on higher floors for a host of reasons. That means that all of the heat created on the lower floors would be trapped

Starting point is 00:10:38 in the building as it rose, and that's not to mention the problem of an entire wall of windows being heated by the sun. Without air conditioning, such buildings would be very uncomfortable or uninhabitable. And it also might be the case that air conditioning has made entire countries viable. In 2010, the founder of the modern nation of Singapore, Lee Kuan Yu, was asked during an interview, quote, anything else besides multicultural tolerance that enabled Singapore's success? His answer was straightforward and surprising. He said, quote, air conditioning. Air conditioning was a most important invention for us, perhaps one of the signal inventions of history.

Starting point is 00:11:19 It changed the nature of civilization by making development possible in the tropics. Without air conditioning, you can only work in the cool early morning hours or at dusk. The first thing I did upon becoming Prime Minister was to install air conditioners in buildings where the Civil Service worked. This was the key to public efficiency. End quote. Air conditioning has become so important worldwide that it's one of the biggest consumers of electricity in the world. For example, India uses over 100 terawatt hours each year just for air conditioning, and the United States uses over 600 terawatt hours. During the Second Iraq War, the largest number of American casualties were from improvised

Starting point is 00:12:01 explosive devices on the sides of roads that detonated near trucks carrying fuel. What was all that fuel going towards? The biggest use was air conditioning. The importance of air conditioning might best be seen in what happens when it disappears. During heat waves that cause power outages, thousands of deaths can result from an lack of air conditioning. Over the last 20 years, 3,142 people in the United States have died from heat-related causes. The majority of them have died in their homes when the air conditioning went out. In 2003, a heat wave in France killed an estimated 15,000 people, the vast majority of

Starting point is 00:12:40 which were over the age of 75 without air conditioning. Air conditioning has become a vital part of the modern world. It allows people to live and work and comfort, and it's allowed the habitation of cities and even countries that would otherwise be unlivable. Even though many people don't think about it, air conditioning has become one of the pillars of the modern world. The executive producer of Everything Everywhere Daily is Charles Daniel. The associate producers are Benji Long and Cameron Kiever. I want to give a big shout out to everyone who supports the show over on Patreon, including the show's producers. Your support helps me put out a show every single day. And also, Patreon is currently the only place where Everything Everywhere Daily merchandise

Starting point is 00:13:26 is available to the top tier of supporters. If you'd like to talk to other listeners of the show and members of the Completionist Club, you can join the Everything Everywhere Daily Facebook group or Discord server. Links to everything are in the show notes.

Everything Everywhere Daily: History, Science, Geography & More - Air Conditioning

There aren't comments yet for this episode. Click on any sentence in the transcript to leave a comment.