Ice build up in DIY glycol chiller

[kgranger]

Will this cause any serious issues with performance? Ice build up pretty bad on the pipe leading to the condenser, and then tons on the condenser itself. I had it set to 25 degrees, but it cannot seem to get any lower than 29 right now. Ambient temp in the brew space is around 80, but I haven’t had any issues until very recently, and it has been this hot in here for a while.

 

[kgranger]

Bumping to see if anyone has any advice on how to prevent the frost build up on the condenser. I turned it off to let it melt away, but is there something I can do to prevent this?

 

[day_trippr]

I imagine it's pretty humid in B'more this time of year. How air-tight is the cabinet all that is located within?

Cheers!

 

[501irishred]

Is that a ball of ice around the evaporator coil as well? Can I assume this wasn’t happening when you were able to maintain a 25deg set point? If the evap coil is allowed to fully freeze, 32 is the best you can really hope for. I’d look at other things that might have changed like pump volume, glycol ratio (if any), position of water inlet/outlet in relation to evaporator coil (try to get the most thermal exchange possible across coil).
ice developing on the suction line (copper line coming back to the compressor) can get worse as humidity increases, but is typically a symptom of a deeper issue.

 

[jddevinn]

The evaporator coil needs to be completely covered by the glycol solution. The part that isn't covered isn't pulling heat out of the glycol, it's trying to pull it out of the warmer air above the glycol.

In my experience any part above the glycol level will freeze very quickly. As soon as it freezes the efficiency of the evaporator goes down and other parts start to freeze. I have my return line go into a "manifold" I made out of a copper tee and four pipe segments with caps and holes drilled down the length to push the returning glycol through the entire area of the evaporator.

 

[kgranger]

thanks everyone for the replies! definitely more humid these past couple months. The container is pretty tightly sealed, but I could try to fill it up to the top with the glycol mixture to cover more of the evaporator coil. I thawed the system out and started over, and I am able to get lower temps again, so it is definitely the frost that is reducing efficiency.

 

[Gruel]

It looks like the frost is on the line from the evaporator to the compressor, not the line from the compressor to the condenser. (The condenser is hidden behind the plywood at the bottom right of your first pic.) That means there is still liquid refrigerant left after the evaporator, which means you are not getting enough heat into your evaporator. I don't think the compressor likes it when it sees liquid at the input.
I think you need to let the system rest until that line and the evaporator have thawed out, and then restart after improving the heat transfer into the evaporator, as others suggested.