Air Conditioning – How it works

Posted in Cooling on July 6, 2011 »

An air conditioner works the same way your refrigerator does except it moves the heat it takes out of your home and dumps it outdoors. The refrigerator does the same except dumps the warm air into your kitchen.

To understand how this happens, we’ll start where the freon gas enters the compressor (located in the unit you see outside).

As refrigerant gas enters the compressor, it squeezes the freon gas that has absorbed heat from your home, causing it to become very hot. Think of your bicycle pump when you push the handle down. The air being compressed at the end of the pump becomes hot because the air in the pump is being pushed into an area much smaller than it was.

This “compressed” freon now leaves the compressor and runs thru a set of coils surrounding the outdoor unit. A fan blows on it to cool the high temperature gas releasing much of the heat. This fan and coil arrangement works similar to a radiator on a car.

As the outdoor unit cools the compressed gas (hot vapor), it condenses into a liquid like steam condenses into water when it loses heat. The high pressure freon liquid is returned to your house via a lineset. It then passes thru a small opening into the evaporator coil
that sits above your furnace.

The tiny entrance into the coil allows the freon to “back up” which allows the compressor to maintain a low pressure with no space in the evaporator. When the cooler high pressure gas passes into this low pressure area, the difference in pressure causes some of
it to expand into a gas. Now the cool refrigerant is occupying a bigger area, so the heat that was left has spread out over its bigger size.

The need to use its limited heat over a now bigger gas molecule causes it to become cold. It then passes through the indoor coil. The air passes over the coil, is cooled and then spread through your home via the blower in the furnace. In the mean time, the heat taken out of your home’s air has entered the warming freon gas so when it gets back to the compressor the whole process is repeated again.

This process is very complicated so you should always have your system serviced by qualified air conditioning technicians. At O’Mara Plumbing, Heating & Cooling, our experienced and trained technicians can repair all brands of air conditioning systems.