Quote Originally Posted by Nuclrchiller View Post
I wonder if condensation was laying on top of the solution in the tank, from humid air entering the equipment room...
that is an absolutely excellent point. i only had 1 chiller that was an open tank and that was a long time ago.

Quote Originally Posted by fxb80 View Post
Are you saying you have chillers with an evaporator SST colder than the solution freeze point?

If flow is enough to keep the glycol in solution regardless of evap temp, is any flow enough? I did some measurements today of the evaporator that prompted this. After deducting approximate refrigerant tubing volume (I have an identical barrel that I cut the top off), the solution volume of the evaporator is 40 Gallons. Flow, corrected for temperature and % ethylene, is about 28 GPM. Evaporator is 2.5' from inlet to outlet. Average fluid velocity is 0.029 Feet/Second or 0.348 Inch/Second. I don't know what chiller normal is but that doesn't seem like much.

I, also, am interested to hear what skpkey9 has to say.
typical minimum flow rates are around 3 feet per second minimum but i don't know what you have for a chiller barrel.

this whole thread seems to me to center around the water molecules separating out or freezing at 32F instead of the SOLUTION freeze point temperature. this is not true in a flowing system. the water molecules are going to stay in solution and not freeze out separately and collect in the coldest part of the system (evaporator).

i do not have any chillers that have a design evaporating temperature colder than the solution freeze point...that would be dumb and counter productive. i have run across systems that were improperly maintained and had an evaporating temperature lower than the solution freeze point (due to low flow rates) and they did occasionally make slush...but i believe that it was a solution slush, not a water slush and the glycol still a fluid.