The History of Air Conditioning (AC) - The Coolest Invention

Welcome, dear readers, to a tale of human ingenuity so chilling, you might want to grab a sweater! Today, we’re traveling back in time to explore the frosty history of one of mankind’s coolest inventions: air conditioning. When it comes to the history of air conditioning and how modern air conditioning systems came to be, you're in for quite a ride. So, settle in and let's get started.

Once upon a time, during the days of the ancient Egyptians, folks had to beat the heat the old-fashioned way. They would hang wet reeds in their windows and pray for a gentle breeze to waft through. We're talking BC—Before Cooling—here, folks!

Fast forward to the Romans, who, like their Egyptian predecessors, also refused to sweat it out. Their approach? They constructed a network of aqueducts to circulate cool water through the walls of their homes. Leave it to the Romans to move rivers to get their chill on!

In the 1720's, Scottish doctor William Cullen observed that evaporation had a cooling effect. In 1748, he demonstrated this by evaporating ethyl ether in a vacuum. He designed a small refrigerating machine that rapidly evaporated a liquid into a gas, creating a cooling effect. However, his design was not suitable for practical use.

In 1758, Benjamin Franklin and John Hadley performed an experiment that tested evaporative cooling. This experiment consisted of evaporating ether and alcohol on the end of a mercury thermometer. This helped draw us closer to the invention of the modern air conditioner because even air conditioning systems today rely on evaporative cooling!

Refrigeration refers to the process of removing unwanted heat from an object, substance, or space. It then transfers that heat to a different object, substance, or space. The invention of the modern refrigerator and modern refrigeration techniques wasn't done by just one person. Instead, a wide variety of ideas, inventions, and discoveries went into perfecting the modern air conditioning unit.

It also includes the idea of mechanical refrigeration. Mechanical refrigeration refers to the process where heat is removed using a man-made heat exchange system. Many innovative minds in the 1800's worked to create systems that could employ mechanical refrigeration.

In 1805, American inventor Oliver Evans crafted a blueprint for the first ever refrigeration machine. Though it was never built, John Perkins created the first practical refrigerating machine based on Evans' design in 1834. This design used a vapor compression cycle.

In the 1840's, Dr. John Gorrie, a physician from Florida, believed that cool air would be key to avoiding certain diseases and making patients comfortable in hospital rooms. His first attempts at cooling the rooms required shipping ice in from the cooler northern states. This meant they would bring ice in from frozen lakes and streams, which proved a logistical nightmare and unsustainable at the time.

So, Dr. John Gorrie began to experiment with the idea of artificial cooling. In 1851, he was granted a patent for his machine design. This machine created ice by using a horse-powered compressor, water, and wind-driven sails or steam. While Dr. John Gorrie was never able to sell this invention, this technology helped create modern air conditioning and refrigeration.

In 1876, German engineer Carl von Linde patented a process of turning a gas into a liquid which became a key part of refrigeration technology.

Many big developments in modern air conditioning were in the early 20th century. So, let's whizz past the centuries of sweaty sorrow and drop into the cool embrace of 1902.

Meet our hero, Willis Carrier, the man who's responsible for creating the first modern cooling unit. The story goes that Willis was just a humble engineer trying to solve a humidity problem at a publishing company or printing plant (because nobody likes a soggy book). And voila! He ended up inventing the modern air conditioning system.

After more experimentation, he created a system of humidity control using cooling coils which he named the "Apparatus for Treating Air." This invention was patented in 1906 and Carrier quickly realized the benefit in humidity control and air conditioning. In 1908, the Carrier Air Conditioning Company formed as a subsidiary of the Buffalo Forge Company. Shortly after, he left Buffalo Forge and formed the Carrier Engineering Corporation with six other engineers.

The organizers of the St. Louis World's Fair in 1904 employed a mechanical refrigeration system and it was one of the first times the American public was exposed to cooling like this.

Initially, air conditioning units were large, expensive, and predominantly used for industrial purposes but the 1920s brought significant advancement. To improve mechanical air conditioning systems, Willis Carrier invented the centrifugal chiller in 1922. His centrifugal chiller used few moving parts and had less compressor stages than other units currently on the market. This helped improve the performance and also brought the cost of large-scale units down.

That same year, they brought air conditioning to the first movie theater in Los Angeles. In 1925, Carrier installed an air conditioning system in the Rivoli Theater in Manhattan, New York. Movie theaters across the country quickly adopted this new technology, promoting "Refrigerated Air" to entice customers during the hot summer months.

Carrier's contraption was a hit and soon, other movie theaters, known as "cool spots," started using air conditioning to lure people in during summer. I mean, who wouldn’t love a double feature: escaping the scorching sun and catching a flick? Pure genius!

However, our beloved AC remained a luxury for the rich and the commercial for quite some time. It wasn't until the post-WWII economic boom that the middle-class could finally afford to chill out, with the invention of the window unit.

Frigidaire introduced a split-system air cooler in 1929. This split-system room cooler was small enough for residential use, but it was extremely heavy and expensive. Not to mention, it needed a separate condensing unit that had to be remotely controlled.

General Electric continued to improve upon this design until they developed a self-contained unit. They produced a variety of prototypes between 1930-1931.

After this, home cooling systems continued to get smaller. In 1932, H.H. Schultz and J.Q. Sherman released an air conditioning unit capable of fitting on a window ledge. However, because they were expensive, they weren't very popular.

Henry Galson, an engineer, developed a design for even more compact and less expensive window air conditioners and, by 1947, these units had become widely popular.

By the 1960s, there was much more ubiquitous air conditioner use. New homes were commonly being built with central air conditioning and sweat stains on shirts became less of a fashion statement.

In the late 60's, central air conditioners became extremely popular in warm-weather states. However, the energy crisis hit in the 70's, and, in an effort to reduce energy usage, lawmakers created laws designed to reduce energy consumption. This forced them to establish federal energy efficiency standards for air conditioner manufacturers instead of individual standards by state.

In 1928, Thomas Midgely, Albert Henne, and Robert McNary of General Motors synthesized chlorofluorocarbon (CFC) refrigerants. As the first non-flammable refrigerating fluids, they were initially designed to make air conditioners safer. However, they were later determined to be ozone-depleting chemicals and were eventually phased out due to the Montreal Protocol.

The Montreal Protocol on Substances that Deplete the Ozone Layer was a landmark environmental agreement designed to protect the stratospheric ozone layer by regulating and phasing out ozone depleting substances (ODS). It was finalized in 1987 and began phasing out refrigerants such as CFCs and HCFCs. CFCs in air conditioning systems were phased out by 1996 while HCFCs were phased out by 2020.

However, we continue to make developments in more environmentally friendly refrigerant options. In 2006, the Energy Department set new efficiency standards and requirements for manufacturers of central air conditioners and heat pumps. Recent developments by the Energy Department's Building Technologies Office and Oak Ridge National Laboratory have resulted in new technologies and refrigerants.

Additionally, you can now find many natural refrigerant options, which are better for the environment. Since they're natural, they don't contribute to ozone depletion or climate change the way synthetic refrigerants do.

So, the next time you crank up your AC and bask in its delightful chill, remember the history of air conditioning including everyone from Willis Carrier to the Egyptian reed-hangers, the innovative Romans and all the other contributors throughout history.

And that, dear readers, is the history of air conditioning. Stay cool, folks!