The evaporator coil, explained
An a/c’s evaporator coil, also called the evaporator core by some techs, is the section of the cooling system where the refrigerant absorbs heat.
The modern evaporator coil is situated inside or near the air handler where the blower fan is.
Quality evaporator coils are made from copper, steel, or aluminum because these metals conduct heat extremely easily, however most residential AC evaporators consist of tubes that are going to be bent into U shapes and set into panels. As the a/c runs, the compressor pulls extremely cold, low pressure liquid refrigerant through the tubing in the evaporator coil. Before finally entering the evaporator coil, the refrigerant passes through the expansion valve. As the liquid refrigerant flows, the blower fan draws hot room air over the evaporator coil. The ice cold refrigerant absorbs heat from the passing air and, as it does so, it warms up and evaporates over time. When the water vapor in your moderate household air hits the evaporator coils, the airborne water vapor condenses into liquid form and drips down into the condensate pan which will eventually drain outdoors. This is how the evaporator coil reduces the humidity in your home and removes moisture. Both evaporator and condenser coils both need to be kept clean to properly perform as intended and reach optimal energy efficiency. A dirty evaporator coil can easily experience a number of issues including impared heat absorption, impaired cooling capacity, much higher energy use, higher pressures and temperatures, and frost and ice buildup on the AC unit. Even a thin layer of dust on the coil can reduce efficiency. Plus, a layer of frost on your evaporator coil is never normal and if your system is running with any amount of frost present on the coil, it can cause the evaporator to fail. Corrosion of evaporator coils can easily also be caused by mixing moisture with chemicals commonly found located in the air and would require replacement.