I have a random 30 gallon aluminum pot laying around and 100' of copper coiled and a few lengths of copper pipe.
I got to thinking that maybe I should build a dual-set of immersion coils into the 30 gallon pot. Where one coil is toward the outer radius and the other coil is on the inner radius. The two coils would each be fed cold water seperately and exit seperately. And for a finishing touch add Jamil's whirlpool chiller idea to keep the wort moving.
(I run my wort cooling water into 40-gallon buckets and use it for cleaning up equipment and the brew house floor.)
To sanitize the wort chiller tank... I expect to clean thoroughly (as always) and drain and leave enough water, in the 30-gallon vessel where the copper coils have been fixed, so as to steam clean via direct application of heat from the bottom. With the 30-gallon vessel sealed from the top, it can be given ample time to cool down (say overnight).
I think it's just a matter of building it at this point. Since all the materials are sitting in my lap (sans a wort pump). I just wanted to throw this out there for you fellas to read.
The advantage I am thinking of here would primarily be in terms of cool thermal mass when the wort is transferred from boil tun to wort chiller tank. The benefits of the concept of running dual immersion chillers with the whirlpool concept go without argument.
The vessel is large enough to maybe use it as a jacket for my 14 gallon fermenter. This is another idea I am thinking of yet haven't posited. I only say this as I am basically done with fighting fermentation temperatures.
Anybody have good ideas for jacketed fermenters? I am always toying with fabricating a trough style fermenter along the lines of the Yorkshire squares: wider at the top and narrow toward the bottom to yield a greater ratio of surface area to volume than I am using now.