Evaporator coil structure
Evaporator coils are used to cool or remove moisture from air streams. They are sometimes called direct expansion. They one of the four main components in the refrigeration or air-conditioning cycle. A liquid-vapor mixture of refrigerant enters the coil and cools the air as it evaporates, and eventually leaves the coil as a gas.
Typical applications for evaporators:
· Comfort Cooling
· Process Cooling
· Air Conditioning
Evaporator Coils come in a variety of shapes and sizes, but there are some properties that are common in most evaporator coils:
Generally, the evaporating refrigerant temperature is closer to the air temperature than a heating coil. Also, to keep water from running off excessively the air face velocity has to be low. Both of these factors increase the number of rows required. Typical Evaporators will have between 4 and 8 rows.
· Tube Diameter
The refrigerants moving through an evaporator have fairly high operating pressures, although they are significantly lower than those in the condenser. There are situations in which ⌀7mm tubes are used, but most commonly we see 3/8" and 1/2".
Connections for most refrigerant applications are copper sweat. Other types of connections are prone to leak, which is a big problem when working with refrigerants.