Air Conditioning Basics

Now that summer is here, I am going to cover some air conditioning basics.

Your central air conditioning system consist of two main components; your evaporator (that thing typically installed above your furnace that turns into an ice block when things go awry), and your condenser (the loud ‘fan’ on the outside of your house).  

Let’s discuss how these work together to keep you from becoming agitated when it is hot outside. In the condensing unit outside, there is a fan (air mover) and a compressor (refrigerant pump), along with a condenser coil. These three components, in one form or another, pump refrigerant into your home (evaporator coil), and extract the heat from your home, but how? In its simplest form, the compressor converts a low pressure low temperature gas (refrigerant, aka freon) into a high pressure high temperature gas, via compression. The high pressure gas then is pumped through your condenser coil, and with the assistance of your condenser fan (the one that blows warm air on your outdoor unit), it cools the gas enough to become liquefied prior to entering your home. As the high pressure liquid is pumped into your house, it hits a roadblock (aka a metering device) at your evaporator coil. As the pressure forces the liquid past the roadblock and into your evaporator coil, it creates what they call a refrigerant flash (now this is getting interesting). Think of the flash terminology as 5,000 people trying to get through one small gate to collect their lottery winnings, which you could imagine would cause people to shoot through the gate uncontrollably due to the pressure of all of those people pushing them. Your refrigerant does this same thing, but as it gets pushed through the gate (metering device), it forces the refrigerant to lose not only pressure, but temperature as well. So at this point, the refrigerant has passed through the metering device and enters your evaporator coil as a cool, low pressure liquid. As this liquid serpentines through your evaporator coil,  your indoor fan blower moves air from your warm house across this coil, resulting in the refrigerant absorbing this heat, causing condensation on the coil surface. As the heat is being absorbed by the warm air blowing across the evaporator coil, the refrigerant “boils” back into a gas and delivers that heat to your outdoor condensing unit, where it repeats this process over and over again. 

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