What Is the Nominal Diameter and Length of Heat Exchangers?

1. What is the nominal diameter of heat exchangers?
The heat exchanger of the coiled cylinder takes the inner diameter of the cylinder as the nominal diameter (DN), and the heat exchanger of the steel cylinder makes the outer diameter of the steel tube as the nominal diameter (DN).

2. What is the nominal length of the heat exchanger?
When the heat exchange tube is straight, the length of straight tube is the nominal length (LN). If the heat exchange tube is U-shaped, and the length of the straight parts of U-shaped tube is the nominal length (LN).