Improving heat transfer efficiency of IC

Would dimpling the tubing of a large diameter (1/2 or 5/8 inch) immersion chiller improve it's efficiency?

My thought is that creating turbulence in the water column within the tubing would negate the stated concerns about the cooler center of the water column not seeing much duty.

If you REALLY want to improve its effeciency, do the whirlpool IC conversion.
I am saving for a pump so that I may be able to make this mod with ease.
-Me

Dimpling would make it harder to keep clean, but you could fish some 14 gauge solid copper wire through the coil to provide a source of turbulence.

Bobby_M said:

Dimpling would make it harder to keep clean, but you could fish some 14 gauge solid copper wire through the coil to provide a source of turbulence.

Click to expand...

ah! a brilliant solution...do you think there'd be a practical increase in efficiency from this or are we talking merely theoretical here?

Good question. I think the practical result would be more evident in short lengths. For example, turbulence in a 5/8" x 25' coil would matter more than a 50' coil. The only way to test for sure is to test it.

I really need to run these numbers, but I am 90% sure that flow at our flow rates within a 1/2" tube will be turbulent. Adding stuff into the tube will not help. I could be wrong, but I am pretty sure I am not.

A 5/8" may be a different story, depending on the speed of the flow.

I agree with Boerderij Kabouter....it's not laminar (plug flow) anyway, so there will be a decent parabolic flow profile, which will give plenty of mixing along 50'.

Edit: Did the math. For a 1/2" pipe with water at 10 degrees C (50 F), at 2 gpm, Reynolds # is 9664. Greater than 4000 is turbulent, less than 10 is laminar, anything in between is up for grabs. For 5/8", it's 7731.

So your flow is turbulent regardless.

Double edit, damn, nevermind, Boerderij beat me to my edit......and his numbers are a bit different, but close enough...chalking that up to temperature choices...

O.K. I needed abreak anyway.

To determine which type of flow exists calculate the following:
Flow rate of the fluid in GPM - Q
Specific gravity of the fluid - G
Pipe inside diameter in inches - D
Fluid viscocity in centepoise - V
Use the following equation to determine the REYNOLDS NUMBER:

REYNOLDS NUMBER = RE = [3160 x Q x G] / [D x V]

Flow conditions with a Reynolds Number greater than 4000 is fully developed turbulent flow. A Reynolds Number less
than 2000 is laminar flow. It requires a Reynolds number greater than 4000 to maintain accuracy.

............................................................

So we set up the equation to find a flow rate (Q) for a given tube to maintain turbulent flow.

We will assume our numbers are for water. Wort will be very close to this and if anything would trend to nmore turbulent flow.

G = 1 g/cm3
V = 1.0020 cP
RE = 4000
D = desired tubing

Q (gpm) = [4000 x D x V] / [3160 x G] = [4000 x D x 1.0020] / [3160 x 1]
Q (gpm) = [4008 x G] / 3160

so... for a 1/2" diameter tube

Q (gpm) = [4008 x 1/2] / 3160 = 0.634 gpm

This means in order to maintain a turbulent flow in a perferctly straight pipe with a 1/2" diamter, the water must be flowing at .634 gallons per minute. Add the turns we have in our chillers and that number drops significantly.

for 5/8" tubing Q = 0.793 gpm.

Basically, we always have turbulent flow so extra baffles are just a waste and are slowing down fluid flow.

:EDIT: I posted this up in my blog for easy reference. http://blogs.homebrewtalk.com/Boerderij_Kabouter/Do_I_have_turbulent_flow_in_my_chiller/

holy carp! thanks for taking the time to go thru that....i could've done it myself, but would've needed to go back to school first.

seriously, i appreciate the effort....sounds like it's not worth messing with.

JoeMama said:

If you REALLY want to improve its effeciency, do the whirlpool IC conversion.

Click to expand...

QFT. Moving the wort around is far more important than the style of the IC itself, in my experience.

Instead of the IC conversion I added a whirlpool fitting to my brew kettle, which also allows me to whirlpool for a few minutes after removing the IC so a lot of the solids settle nicely in the center, away from my pickup tube.

I got the idea from a trip to a local brewery. As part of their tubing runs, they can recirc the wort in the kettle causing a whirlpool.



-Joe