[Stevie]

I think Marshall should run an test on fast versus slow. Compare time to gallons of water used. I'm sure slow isn't heat sink efficient and full bore isn't water efficient. There must be a point where the lines cross.

[tonyccopeland]

I experimented when I brewed last week.  I know this is all qualitative..., in previous batches my 20ft  3/8 in. IC at a slow flow rate for a 5 gal batch would cool from boiling to 100 in 45 minutes using 10 gal of water.  I increased the flow to use just over 15 gal and it decreased the cooling time to around 15 minutes.  I move the IC up and down constantly while running the water.  Looks like my garden gets a little extra water on brew days. 
I am still planning to get a hydra IC sometime this winter... So I can brew  and cool larger batches.

-Tony

[hopfenundmalz]

This is true. Running full on will give you more delta T across the chiller length, and the water comes out cooler, but it is taking more heat energy out, think M-dot*(T_out-T_in). The high Mass flow rate (M-dot) will carry the heat away.

Shut up, Dr. Kallio, I already passed your thermodynamics class!!!

Sorry...PTSD flashback.

Anyway, good to know.  I heard somewhere to run the water through the IC slowly.  Next time I brew it is full blast.

I learned that in the Heat Transfer class.

My Thermodynamics Prof. was Charles Brown, AKA. Charlie Brown to all of the Engineering students.