During lunch at work yesterday, I was reading the high volume wort chiller thread
during lunch and thought, "Hey, I think I can take this to the next level"
So I started thinking up a design, its sort of a cross between a shell and tube and counterflow heat exchanger. It would use 6 1/4" copper tubes split from a 1/2 inch inlet. There would be three inner spirals in one direction with 3 concentric spirals in the other wrapped on top of the inner layer. There would be a 1.5" PVC pipe or something to force all flow to run over the coils instead of down the middle with a 3" PVC shell on the outside.
With this design, it would use about 40' of copper pipe with about 350 in^2 of heat transfer surface. I imagine turbulent flow would be maintained in the shell as there would be many regions where the flow can mix.
If I were to build this, chilled water would flow through the shell on the opposite section of the wort. Probably just drill some holes in the PVC and epoxy in some fittings.
I made a (not so) quick model of it and have some images below. My poor laptop really didn't like this
Both sides would be enclosed of course. Also, the far side would be terminated as the close side in the rendering. It was just killing my comp so I didn't draw it.