Most condenser coils are designed with either 1/2” or 3/8” O.D. tubes. Condenser coils are sized to handle the cooling load as well as any desired subcooling and also the heat of compression from the compressor. The type of condenser fan being used and its static pressure capability may be a significant determining factor in the coil design. The subcooler circuit (if provided) will often be integrated into the header design.
The most commonly used tube material is copper, and there are a variety of tube wall thickness options to handle different applications. Aluminum is the most frequently used material for the fins on a coil, because of good heat transfer characteristics and low cost, but copper fins are also common in coastal areas. There are many different fin designs that will either enhance heat transfer or reduce air pressure drop, depending on the requirement. Coil frames (or casings, flanges, whatever you might call them) are normally galvanized. Protective coatings are sometimes utilized in harsher atmospheres such as salt spray or chemical environments. Connections are almost universally made from copper.
Keep in mind that although there are a huge variety of material options available for coil designs, unless there is a design reason to specify something special, most coils will be purchased based on the cost alone, so using the “standard” coil material is generally the approach to take.