I am looking for a method of detecting ice build-up on submerged refrigeration coils. The "coils" are 1.5" dia. SS tubing in which refrigerant circulates. They are submerged about 48 inches to maintain a water bath at 33F. I want to detect the formation of ice, which is detrimental. Has anyone found a satisfactory method to do this?

 

I have heard of people using changes in resonant frequency or amplitude to detect icing. I haven't tried it myself, so I don't know how the details work or just how well it works.

However, the theory is to apply a known vibration to the monitored element at frequency corresponding to its normal resonant frequency. You then monitor the actual vibration amplitude. Accumulation of ice will change the amount of damping (or the resonant frequency - I'm not sure of this point). You then monitor this factor for changes over time.

That has exhausted my knowledge of the subject, but it might help you in searching for an answer.

 

Our refrigeration guy supplied us with an ice detector which is installed on what sounds to be a very similar situation. I believe it is a Johnson Controls device. It is one of the old remote bulb type sensors with a long capillary and a mechanical contact. I am sure there must be more sophisticated techniques out there but hey.....no electronics...nothing fancy...and it does the job for us.

Cheers,
Gerald