Answer: Because the cold dryer performs condensation heat exchange of compressed air. In the process of condensing water vapor into water droplets, a layer of water film must first be formed on the outer wall of the copper tube. The horizontal arrangement can make the water film drop rapidly in the form of beads. If it is arranged vertically, the water droplets will flow along the surface of the copper tube in a curtain-like manner. The curtain-like flow makes the water film thicker and affects heat transfer. Therefore, the evaporator copper tubes in the cold dryer are mostly arranged horizontally.
