How does Central Air Conditioning Work?

How does Central Air Conditioning Work?
October 29, 2015 nobleair

Living in a dry, arid climate like the Valley of the Sun means that having a residential air conditioning system is a must. For much of the year, outside temperatures are quite warm (read: hot) and to keep a home comfortable, people rely on their HVAC system. While you probably enjoy the function of your air conditioner greatly, you might not understand how it works. Many people know it contains refrigerant and a fan. The filter and ductwork are also commonly known, but how it actually works remains much of a mystery to most people.

How does Central Air Conditioning Work?

All air conditioners employ the same basic elements and use similar principles to keep a home cool. It’s how they are configured which makes systems differ from one another. The most common type of residential air conditioners in the country are central air conditioning systems called “split systems.” These have an encased compressor and condenser, usually installed outside of the home and an air handler and evaporator coil, which are generally found inside the house, in the attic, or even garage.

So how does a typical air conditioning unit work and keep you sane during the heat? The basic concept is that a chemical called a refrigerant loops from inside the home to outside and back again, absorbing and casting out heat in the process. The refrigerant cools and then re-enters the home, starting the cycle anew —Live Science

Heat pumps are another type of unit which function according to their namesake — they pump heat out of the home during the summer. The process is reversed during the winter, when warm air is pulled inside. Packaged central air conditioners are more common to commercial spaces, usually situated on a concrete slab. Ductless mini-split systems are typically mounted high on an interior wall and their main components are placed outside.

Now that you know some of the differences between systems, here’s how central air conditioning works:

  • Refrigerant or coolant. This is a liquid which is changed into a gas that cools the air forced into a home. It’s changed back into a gas once circulated and the process repeats again and again. When refrigerant gets low, the forced air becomes warmer and warmer.
  • Evaporator. This component is what changes the refrigerant from a liquid to a gas. Evaporators contain a fan which pulls-in warm air, exposing the heat to the coolant, and producing the gas which cools the air that’s blown into the home.
  • Compressor. The compressor does precisely what it’s called: it compresses and therefore pressurizes the gas, causing it to heat.
  • Condenser. This part does the opposite of the evaporator by turning the gas back into a liquid.
  • Expansion valve or device. Cooled air flows through this component slowly, dropping the pressure and helping to cause the gas to be turned back into a liquid. The liquid is then run back through the system again.
  • Outdoor unit. This is the housing unit which contains the condenser, compressor, and expansion device. It typically contains fins to allow heat to be released away from the system.
  • Ductwork. Made of different types of material, ductwork handles air circulation through an organized network.