How does air conditioning work exactly? The simple explanation is that heat is removed from the inside of the house or room and released outside. To really dive deep, though, you need to ask yourself, “What are the components of an A/C unit?” There are five main parts that make the process of removing heat possible: the refrigerant, a compressor, a condenser, an expansion valve and an evaporator coil. Let’s take a look at each one and the function it plays in making your life a little easier to tolerate.
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From A to C
First things first: Let's take a look at how the air conditioner came about. Along with the Easter Bunny and the Tooth Fairy, air conditioning is one of the great mysteries of the universe, right? Well, no. Like many other science-based inventions of the past, someone identified a problem and set out to find a solution. This particular someone was Willis Carrier. Surprisingly, the problem was not uncomfortably hot air; it was humidity control at a printing company in Brooklyn, New York. In 1902, Carrier designed a machine that increased humidity levels by heating water and decreased humidity by cooling it. So the cooling aspect was actually a byproduct of the process of dehumidifying air. That became the first air conditioner.
With WWI, the crash of the stock market in 1929, then WWII, the industry was slow to reach the middle class market until the baby boom years of the 1950s and 60s. Now, with air conditioned homes, workplaces, stores and cars, many people spend a minimum amount of their time in unconditioned air.
Basic principles – refrigerants
At the most basic level, air conditioners operate on the principle that liquids absorb heat as they convert to gases. Residential air conditioners use two common refrigerants to achieve this process on demand: R-22 and R-410A, both hydrochlorofluorocarbons.
R-22, also known as Freon, was the most common air conditioning refrigerant for decades. However, the Environmental Protection Agency (EPA) has identified it as a substance that depletes the ozone layer and has enacted a plan to completely phase out its use by 2020. It is being replaced by R-410A, a more environmentally friendly alternative.
Regardless of which refrigerant your unit currently uses, they both serve the same basic purpose: to absorb heat from the air within your home and convert from a liquid to a vapor, cooling the air.
Of course, that’s not the end of the story. Besides refrigerants, your AC unit has four key parts that each play an important role in maintaining a comfortable temperature inside your house.
Common refrigerants include:
- “Freon,” which is referred to as “R-12” and is known to harm the ozone layer. Production was phased out in 1994.
- R-22, which is slightly less harmful to the ozone layer than R-12 and is slated to be phased out by 2020.
- R-410A and R-134, which are safer refrigerants and are being used to replace R-22.
