TTM2
Mechanical
- Nov 20, 2013
- 9
See attached PDF for general piping layout. The idea is that the chiller unit cools the incoming water which is then pumped ~100ft in the air to cool a piece of equipment at higher pressure. My return line is filled with bubbles and unpredictable behavior which I have never observed in lab settings.
I had run this system in a shop before, all components tabletop with minimal elevation gain, with water. I was able to tune the bypass needle valve to hit the flowrate I needed, while staying within our pressure ratings of the pump, and there was no funny business in the water return line (bubbles, cavitation, noise etc).
Now it is installed in "real life" and must move 50/50 water+glycol up 100 feet to cool a piece of equipment in 3/8-1/4 copper tube. The return line has the flowmeter (standard rotameter with clear plastic so bubbles are easy to see). My return line is filled will all kinds of nonsense like chaotic bubbles, jumps, whooshing. Very inconsistent.
At first I thought the bubbles were trapped in the line and working their way out, but after running ~4 hours they are as bad as ever. Is there cavitation in the line, or lowering of the vapor pressure on the return line downwards forming bubbles? I need to nail a certain flowrate and I need to use my bypass needle valve to tune it.
I had run this system in a shop before, all components tabletop with minimal elevation gain, with water. I was able to tune the bypass needle valve to hit the flowrate I needed, while staying within our pressure ratings of the pump, and there was no funny business in the water return line (bubbles, cavitation, noise etc).
Now it is installed in "real life" and must move 50/50 water+glycol up 100 feet to cool a piece of equipment in 3/8-1/4 copper tube. The return line has the flowmeter (standard rotameter with clear plastic so bubbles are easy to see). My return line is filled will all kinds of nonsense like chaotic bubbles, jumps, whooshing. Very inconsistent.
At first I thought the bubbles were trapped in the line and working their way out, but after running ~4 hours they are as bad as ever. Is there cavitation in the line, or lowering of the vapor pressure on the return line downwards forming bubbles? I need to nail a certain flowrate and I need to use my bypass needle valve to tune it.