Tropical Wort Cooling

[big d]

fellow ahbs
heres a problem for tropical ag brewers that some may have an answer too.
reading charlie papazian,s the home brewers companion page 153 he mentions that cold does not travel only heat does.
mmmm i thought there i was going to run a pre chiller/copper coil through an ice slurry before entering the kettle to chill the wort down to yeast pitching temps.
i woke up from night shift this arvo and thought i would have a test run and buggered if i could get the temp below 25 degrees.
mind you i didnt have a complete ice slurry at the time just some frozen blokes of ice in a 22 litre bucket then into the kettle.
as im in the test stages of an ag set up before the first run in 04 im looking for any ideas or thoughts that may help.
im thinking of something similar to batz,s photo set up of running the copper coil through an ice slurry in an esky set up before hiting the kettle cooler but in the esky of ice adding 10-20litres of pre chilled water to keep the temp way cool.read about 0-2 degrees of cool water to the ice in esky.
any thoughts appreciated.

cheers
big d

 

[JasonY]

Big D, the prechiller that batz had should work a treat, you just have to make sure you have maximum cold liquid in contact with the prechill coil - so an ice slurry is best (some salt may help too ... not sure on that one as to wether you need to freeze salty water (lower freezing temp) or just bung it on the ice.

Can't say I have tried this but if you can - maximise the coil length and as per the other post use plain tap water to drop the temp initially to save some ice.

Can't say I have read Papazian's book but the basic laws of physics say that this will work B) I think he is making a point that energy flows from the hot medium (water in coil) to the cold medium (the ice slurry) ... bleh you can think of it whatever way you want but it will cool.

 

[Guest Lurker]

No experience to offer, but in theory: Yes you can think of it as only the heat travelling, but it still works, in this case the heat in the tap water travels through the copper wall into the esky of ice water and warms it up a bit.

In theory maximum heat transfer comes from sufficient time in contact (slow the tap down so the water spends longer in the coil), and maximum temp difference between the water in the coil and the water outside the coil (maybe jiggle the cold coil around to prevent a buildup of warm water against the coil). Did you give the ice esky long enough to get to equilibrium with the ice before you started (did you have tap water in the bucket at 20 degrees and ice in the bucket at 0 degrees, with heat still travelling in between?

I know a lot of people dont agree with it, but you would get maximum cooling efficiency by omitting the two heat exchangers and shoving the ice directly into the wort, if you could afford some dilution!

Just some thoughts.

 

[big d]

thanxs jason y and guest lurker(simon)?
im just doing pre 04 mash experiments with my set up so far.i must admit gl that the time was rather short with tap water added to the ice slurry and being in the tropics 32+ every day the ice didnt last too long.i think the tap water is around 25 degrees +.ive even had an idea of immersing the copper cooler coil in a bucket of water and bunging the lot in the freezer before brew day then taking it out at wort cooling time and connecting it to the set up and letting the tap water flow.maybe i should patent the idea as i havent heard of it being done before but reckon this would be the ultimate pre cooler set up.i will give it ago sometime and post pics maybe over the next few days if i can convince the handbrake to free up a bit of freezer space.

cheers
big d

 

[Doc]

Basically like the others have said, I would approach it in two steps.

The first would be to first run normal tap water (if you call NT tap water normal at 32 deg) through your immersion chiller in your boiler. This will still help drop the temp from boiling.

When you have removed the bulk of the heat, then start using the pre-chiller in ice and then use it to bring the temp down the last x degrees.

Also have the water flowing through the chiller at a slow rate.

Beers,
Doc