Understanding How Your A/C Works

To most people, the science behind air conditioning is pure magic. The process cools your house and that’s all you care about… until it stops working. However, a basic understanding of the process behind air conditioning will provide you with a better ability to troubleshoot problems. Evaporator and condenser coils are at the heart of this process.

Why Refrigerant Is So Important

First, it’s important to understand how refrigerant plays a role in air conditioning. It easily transitions between liquid and gas, and when it does, it either extracts heat from the air or releases heat into the air. Pressure aids the process.

How an Air Conditioner Works

In a split-system central air conditioner, liquid refrigerant, also called coolant, is pumped into the home. It flows through an evaporator coil, which is either located in a dedicated air handling unit or attached to the furnace plenum.

Before the coolant flows into the evaporator coil, an expansion valve reduces pressure on the refrigerant, causing it to evaporate into a gas. As this happens, the refrigerant extracts heat energy from the surrounding air. The removal of heat from the air cools it off, and that cooled air is blown away from the coil and circulated throughout the home via a blower fan and air ducts.

At this point, the A/C pumps the gaseous refrigerant back outside to the condenser/compressor unit, usually located on a concrete pad next to the house. The compressor squeezes the gas, turning it back into a liquid. As the returns to a liquid state , heat is released into the outside air, blown away by an exhaust fan.

All air conditioning systems — central, portable and package units — operate on the same principle. Electric, air-source heat pumps cool homes in this manner as well, using a reversing valve to switches the process from indoor cooling to heating. When this happens, the indoor evaporator coil operates as a condensing coil during heating, and the outdoor condenser coil becomes an evaporator coil.

When Your System Isn't Cooling

If you notice your A/C isn't cooling right, always check to see if any of the breakers have tripped and verify you have changed your filter recently.If you notice the system not cooling properly, check to see if there is any ice forming around the insulated line coming off the evaporator coil or condenser outside. This a sign the system is low on refrigerant, and you should turn the system off right away and contact a professional to assess the system. Be sure to keep it turned off until a tech arrives, even after the ice has thawed. Just like you wouldn't run your car with out oil, you don't want to run the A/C without refrigerant.

For more information on how evaporator and condenser coils cool, please contact Self Heating and Cooling at 678-909-6377