This is more of a thought experiment since I don't have time to do the research right now.
1. So far I've been cooling my wort using my double-coil immersion chiller. One coil sits in an ice-water bath and the other in the wort. I run water from the garden hose through it.
2. Another idea is to run the ice-water into the IC and have both coils sitting in the wort. My coils are conveniently coiled at different diameters so they fit inside each other nicely.
It doesn't seem like the tap water in technique 1 gets down to ice water temp by the time it leaves the 1st coil. However the water is already pretty hot by the time it comes out of the 2nd coil in the wort. Even if I got it down to ice water before it went in would it be doing much cooling in the 2nd coil if it were immersed?
I guess I could go look up some formulas for cooling rates etc. Is there a resource for any experiments on this?