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How A/C works

How Central Air Works

Central air conditioning is a necessity in south Florida.  But it’s also a mystery to most of us. How does central air conditioning get and keep our homes so pleasantly cool? What do you do if your air conditioner breaks?  Here’s some basic information about the way your central air conditioner functions to help you understand

Air Conditioners Draw Heat Out
Air conditioners basically function the same way as your refrigerator does. In fact, your fridge is essentially an air conditioner that’s attached to an insulated box. Both of them work on the theory of drawing heat out of a room or other space (not, as is commonly believed, adding cool air into it). The final result is a space that has less heat in it, offering a much cooler feel.
Air conditioning also takes advantage of the way evaporation works to make us feel cooler. Ever had a swab of alcohol placed on your skin? The fast evaporation of the alcohol made your skin feel cool, but it wasn’t actually lowering your skin temperature, just drawing heat from the air to turn the alcohol into a gas.

Air conditioning units have a special kind of chemical in them, referred to as a refrigerant. Freon was one of the older chemicals used for this purpose, but its ozone depleting effects have caused it to be replaced by other substitute refrigerants. All refrigerants have the ability to evaporate, or change from liquid to gas, in a very short amount of time.

At the factory, the refrigerant will be pumped into the air conditioning or other cooling unit, plus some lubricating oil to keep the compressor working. It should never exit the unit, and if you have a refrigerant leak, you’re losing cooling ability, as well as causing environmental damage. That’s why correct central air conditioning installation and routine checks are important.
There are a number of basic parts to the average central air conditioning unit. They are the:
    •    Condenser (Outdoor Coil)
    •    Evaporator (Indoor Coil)
    •    Compressor
    •    Expansion valve
    •    Thermostat.

An air conditioner may also have thin metal fins on the condenser and evaporator. These allow heat to quickly be dissipated. The compressor is usually the heaviest part of the unit, as it has to be strong enough to stand the immense amount of pressure it’s under.

The Air Conditioning Process

1) The refrigerant enters the compressor. This usually happens at the bottom of the unit, but some other arrangements exist. The refrigerant is a cool gas at this point, but as it enters the inner chamber of the compressor, it is compressed, becoming an extremely warm gas under very high pressure.

2) The refrigerant then passes through a number of condensing coils that are located outside of the house. The heat in it dissipates into the air outside, the same way a radiator in a car removes the heat from engine coolant. Once the refrigerant makes its way to the end of the coils, it’s a lot cooler, has condensed to a liquid but still under a lot of pressure. It’s a lot like the liquid in an aerosol can, in fact.

3) The liquid refrigerant will then be forced through an extremely tiny opening. This is the expansion valve, and it works a lot like that aerosol can’s sprayer, creating an extremely fine mist of refrigerant. Refrigerants evaporate at a much lower temperature than other liquids, including water, so they start evaporating quickly as they travel through another set of coils.
This evaporation works like the alcohol on your skin, drawing heat from the surrounding air in your home. The fans blow air across metal fins that are located over these coils. Air comes to them through the duct work in your home, and leaves feeling much cooler.

4) Now the refrigerant in the gas stage goes back into the compressor. It keeps going around and around through the system until the thermostat registers that a specific temperature has been reached. Then the compressor shuts off and the action stops. Once the room warms up again, the thermostat sense this added heat, kicking the compressor back on again to pressurize the refrigerant.

Efficiency is Important
Of course, your central air conditioning system won’t have to work as hard or use as much energy if you take other measures to keep your home cool, like keeping the doors closed and the window shades down, and sealing air leaks that could cause the heat from outside to come into your house.

A central air conditioning unit is much more efficient than a window mounted air conditioner, as it is able to cool the whole house. Installation in homes that already have forced air furnaces is simple, too – that’s because you can use the existing duct system and just hook the air conditioning equipment up to it.

If your home is older and uses radiators, or some other method of heating, installation of a central air conditioner may be more complicated and costly, since the house will have to be fitted for ductwork. Remember to choose a unit of the correct size to cool the space in your home – units that aren’t large enough won’t provide enough cooling, and overly large units may be a waste of energy.

Expert Installation of Your Air Conditioning System
Installing a new, energy efficient central air conditioning unit is an excellent decision for any home owner who wants to add value to a home and improve the comfort of living. This upgrade can make a big difference in how your home feels in the summer.
Just remember it’s important to have your air conditioning system installation performed by an experienced professional. To keep your system in tip-top shape, consider our air conditioner maintenance agreement. You’ll save money in the long run by keeping your unit maintained properly.

If anything goes wrong, don’t hesitate to call us. It’s important to have your central air conditioning system serviced by FMH Hvac Air Conditioning and Refrigeration , we are the experts.