Resonance Sound in Copper Pipes

Please consider rechecking your calculations for pipe sizing.

It may be vibration caused by high velocity flow due to undersized pipe.

Possibly the pipe support spacing is just right that one or more sections of the pipe is resonant to the vibration from the chiller. Try locating the points of greatest vibration by touch and add clamps.

For the same reason you can make a Fife out of copper pipe/tubing, Resonance. Depending upon the length and size most pipes have a "natural frequency". Most times it is below the discernible pitch of the human ear but it is there.

It is also possible to make Trumpets, coronets, Clarinets and many other musical instruments out of copper pipe/tubing. A whole lot of work but how many people have played The 1812 Overture on a copper flute with the Boston Pops on July 4th?

Good Luck, Old Salt