Which chiller liquid?

[kladue]

I am guessing at the interior dimensions of the freezer, but came up with a possible method using 4" PVC pipe capped on bottom. The approach was to fabricate 4" pipes and install 4 -5/8" od equally spaced copper loops inside pipe and fill with water to within 1" of return elbows on top. If the guessed at dimensions are correct then you could fit about 14 -32" pvc pipes and 4 22" pipes in chamber and connect copper to flow through all of the pipes in series.
some assumptions on loads and capcaities.

10 gallon batch size, 84.5 Lbs liquid
212 degree boil to 60 degrees, 152 degree delta
cooling needed 84.5 Lbs X 152 delta = 12,844 btu's
Btu's to melt 1 Lb ice = 144
4" Dia X 30" icecube with copper coil = Net 13.46 Lb ice, 1938 Btu's
4"Dia X 20" icecube with copper coil = Net 8.92 Lb ice, 1285 Btu's
Possible loading of freezer might be 14 -32" containers + 4 22" containers 32,272 Btu's possible.
The unknown is the efficiency of the ice melt and water temperature rise in pipes, but running the liquid coolant through the pipes in series might work. It would be prudent to build one pipe and test it to observe performence or lack of before building a larger system. The freezing water should grow verticaly in the tubes and not burst the sides, if one is concerned about that a strip of the 1/8" closed cell packing material taped to the inside of pipe should compress enough to prevent bursting.

 

[Yorg]

That's a very good idea. As you say, would need some testing - particularly as ice expands about 9% upon freezing. I'm wondering what other material would serve instead of the PVC, and would allow for some expansion.(?)

With your BTU calculations:
I imagine that ice at -10C has greater cooling capacity than ice at around 0C. Were your calcs based on 0C?
From your calcs, it seems getting down to lager pitching temp would be quite possible.

Once more, my main concern is that the pump would be able to handle coolant much below zero.
But perhaps I've missed your point, is it ice at about 0C that you are suggesting and making your calcs upon?

 

[kladue]

I was trying to be conservative as only the heat absorbed during melting of the ice was used, the temperature below 0C, and the temperature rise of the water liberated during melting was not included. The container is not that important but thought that the easiest to build and place inside the freezer would be 4"(100MM) pipe used for drainage. If the ice is allowed to grow verticaly the pipe should survive the experience. One thing that was not calculated was the pressure drop through the inner tubing when circulating coolant, might need to make paralell loops to limit pressure drop instead of one long series loop.

 

[Yorg]

I believe I will try this.
I'll let you know how it goes.

As for the pressure drop - I wonder if this is actually an issue, as it would probably mean a bit of suction leading back to the pump and giving it a little help for a moment.
Cheers.

Have you been monitoring the diy peristaltic pump build? Your suggestions would be very helpful.

 

[kladue]

My experience with peristaltic pumps is limited to the small displacement types used to move reagents in instrumentation, this large displacement pump system looks interesting. There are few options for self priming pumps for brewing and this method looks interesting if the tubing can hold up under the rollers without splitting or remaining flat under suction. Currently assisting Beerthirty with his build and have incorporated some automatic air vents in the pump piping to see if he can overcome the priming problems and be able to operate his system automaticaly with the brewtroller. When the wet testing is finished he can let folks know how the experiment with his new system has worked out, hopefully it will deal with the march pump priming issues.

 

[ChshreCat]

Sugar water has similar properties as salt water when it comes to the freezing and boiling points. And if it gets in your wort, you just get a slightly dryer beer.

 

[Yorg]

Instead of using air vents, for my brewtroller build, I am dedicating a valve on the outlet side of the pump as an inlet for mains water. I will be back-flushing the pickup tubes of the tuns to expel air bubbles and allow the pump to prime. This will be part of the session setup, but also between batch sparges.
But that's another thread, I think i'll post on that forum.

 

[Yorg]

Got a chance to prove the concept:
Allow about 10% of the length of the pipe for expansion.
The pipe will not burst.
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