#810 When was the first air conditioning invented?

When was the first air conditioning invented? It was invented on July 17^th, 1902.

The first electrical air conditioning, the predecessor of what we use today, was invented in 1902, but people have been using forms of air conditioning for thousands of years. The first methods to cool buildings relied on architecture. Ancient buildings have been found with double walls, giving a space for air to flow through. Over 4,000 years ago, Ancient Egyptians hung wet reed mats over their doorways and windows. When the water evaporated, it took heat out of the building in the same way that our sweat evaporating takes heat out of our bodies. Egypt has a dry climate, so people also used shaded open spaces. Keeping out of the direct sunlight can reduce the temperature. The Egyptians also used something called a malqaf, which means “wind catcher”. It was an opening raised higher than the building that captured cooler air and blew it down a pipe into the house. They used awnings to provide as much shade as possible and they built their houses in light colors so as to reflect the heat.

Later, the Romans came up with a system of using water to cool their houses. They had designed aqueducts to carry water into the city from lakes and rivers in the countryside. They didn’t use pumps, relying on gravity to carry the water. In some wealthier people’s houses, the water was directed through pipes built into the brickwork. The water absorbed the heat from the bricks and the house, carrying it away and keeping the house cool.

People made use of these methods for the next few thousand years. In the 16^th century, scientists started to find different ways to cool things down. One method was to add salts such as potassium nitrate to ice, which lowered its freezing temperature. Benjamin Franklin discovered that things could be cooled using forced evaporation. By evaporating alcohol or ether off an object, they could lower its temperature dramatically. This was interesting, but it was still a long way from the air conditioning we have today and without electricity it was too difficult to make.

In the 19^th century, people discovered that compressing different substances could cool the air around them. A doctor called John Gorrie used this method to make ice and to cool rooms in a hospital for people with Yellow Fever. Modern fridges and air conditioners use compressors. They work because when air is compressed, its temperature rises. The compressor has a tank of air and a piston to compress the air. As the air is compressed, the heat energy the air holds is squashed down into a smaller space, making the temperature rise. The very hot air is then fed through a tank of cool water and the water takes away a lot of the heat energy because heat always moves from a hot place to a cold place. Once the air has been cold, the piston releases the pressure and the air expands back up to its original size, but now it has much less heat energy and is far colder than it was. This cold air can be used to take heat out of other objects, such as a fridge.

Electricity was becoming widespread by the end of the 19^th century and, in 1902, Willis Carrier invented the first electric air conditioner. He worked in a publishing company in New York and every summer the paper would become unmanageable due to the humidity. According to the Carrier air conditioning company, he was sitting on a train platform in very foggy weather. He suddenly realized that he could remove moisture from the air by passing it through water to create fog. Carrier set up an industrial fan in the publishing factory and blew the warm, humid air over coils filled with cold water. The moisture in the air condensed on these coils, making it drier and cooler. He had made a machine that reduced humidity and cooled the air, which was the first real air conditioner. It took him several years to get it working perfectly, but he applied for a patent and set up the Carrier Air Conditioning Company, which is worth $18.6 billion today.

The first sir conditioning unit for a house was installed in 1914 and the first air conditioning unit for a car was invented in 1932. They were extremely expensive, although, as with any technology, the price started to come down as more people bought them and they improved. Today, many homes have air conditioning and they will become vital as the global temperature keeps rising. One of the problems with them is that the energy they require to cool the air is one of the reasons why the global temperature is rising. Also, the hot air they release into the air outside the house raises the air temperature. Plus, many people that desperately need to cool the air they live in cannot afford them. And this is what I learned today.

Photo by Suleyman Seykan: https://www.pexels.com/photo/white-concrete-building-in-low-angle-photography-6344882/

Sources

https://www.daikin-ce.com/en_us/daikin-blog/the-history-of-air-conditioning.html#accordion-d0d367eaee-item-f01f86f6db

https://www.cambridge.org/core/services/aop-cambridge-core/content/view/6317345C8FB8B405AADE7BA99CD62E8B/S1359135501001312a.pdf/passive_downdraught_evaporative_cooling_principles_and_practice.pdf