Do You Know How Air Conditioning Works?

In 1902, Willis Carrier, an American engineer and the savior of our entire species, invented electrical air conditioning. Life would never again be the same, particularly for anyone unfortunate enough to live in tropics-like locations.

The kids won't leave the thermostat alone no matter how often you yell at them. The most important functions of modern A/C are to reduce the moisture and temperature of interior air.

All modern A/C units rely heavily on a refrigerant in order to perform their cooling duties. Refrigerants vary depending on the manufacturer and region.

There's no dryer in an A/C unit. But to be fair, the machines do make the air feel "drier" as they work their magic.

Refrigerants are specially formulated for air conditioners. Their primary trait is that they can quickly change from gas to liquid and back again throughout a long, hot day.

When liquids convert into gases, they have a useful property … they absorb heat. That principle is the basis for modern A/C contraptions.

Air conditioners circulate refrigerant chemicals through a series of metal coils. These coils provide a means for the chemicals to undergo their vital phase changes.

The refrigerant passes through several stages during the cooling cycle. As it passes through the evaporator it, of course, evaporates.

The unit's refrigerant evaporates and then condenses, over and over again. In the process, it helps cool interior air.

Evaporator coils contain chilled refrigerant. That refrigerant absorbs heat, and then cycles back through the system.

After refrigerant absorbs heat in the evaporator coil, it circulates to the condenser coil. The condenser is outdoors, where it can release excess heat.

Once the A/C unit conditions -- cools -- the air, it must force it back into the area you want to chill. It uses high-speed fans for that task.

In the evaporator, refrigerant turns into a gas. In doing so, that "phase conversion" allows the chemicals to absorb heat.

Refrigerants are not always environmentally friendly. Older types, when exposed to air, would damage the Earth's ozone layer, creating a whole range of potential problems for plant and animal life.

The heated refrigerant is a gas when it hits the condenser coil … and then it releases its heat and becomes a liquid again. It's a simple but efficient cooling solution.

It is chlorodifluoromethane. It is R-22. It is what allows you to breathe indoors in North Carolina in August. It's also being phased out in modern countries due to environmental concerns.

The compressor takes the vaporized refrigerant and increases its pressure and temperature. Then, that refrigerant is sent off to the condenser.

As the heated refrigerant travels into the condenser, air passes over the condenser coils. That air carries off excess heat.

Condenser coils cool well with air flowing over them. But they are even more effective if cool water is circulated over them.

The condenser pressurizes and heats the refrigerant. Then, the refrigerant moves toward the expansion valve.

After being heated and pressurized in the condenser, the refrigerant hits the expansion valve. There, the chemicals quickly drop in pressure and temperature in what's called "flash evaporation."

How badly do you want to cool off on a hot July day? Badly enough to risk using incredibly flammable refrigerants in your house? That's what people did, sometimes with fatal results.

A/C units rely on flash evaporation to quickly turn the refrigerant from liquid into gas as part of the cooling process. But uncontrolled flash evaporation can be hazardous -- it can lead to explosions.

The machine uses fans to circulate hot interior air across the evaporator's coils. Then, the evaporator absorbs that disgusting heat and blasts it outdoors.

False. The condenser and evaporator are housed in discrete portions of the machine. Otherwise, one would warm the air and the other would cool and nothing would improve your living circumstances.

It's called a heat pump -- it's the opposite of an air conditioner. And it can warm your house during wintertime.

Willis Carrier's invention became more refined in the 1920s and was set for a revolution. But then the Great Depression hit, and no one could afford air conditioning … or even mortgages.

Too dry and your lungs will dry up; too much relative humidity and you'll feel sad and soggy. Modern A/C units create an RH level of around 50%.

Roughly 87% of America homes have A/C. The only people crazy enough to go without A/C live in Alaska.

By reducing the temperature of interior air, A/C units also force that air to lose some of its moisture. That makes them dehumidifiers, too … and they make summertime much, much more bearable.