DIY Idea/Theory - Counter Flow Double IMMERSION Chiller

[Philip1993]

My roommate theorized something about heating/cooling water causes some sort of current in the pot. Not sure why, but he figured the cold wort would somehow move away from the coil and draw the warmer wort in for some reason. Again, I dunno, it was a crazy (drunk) theory.

Convective currents would be established, causing the cooler fluid to tend downward. But, that effect is very small compared to the reduction in thermal movement caused by the boundary layer of cooler wort near the pipe.

What that means is that (as said before), you maximize efficiency by keeping the wort in constant circulation around the coils.

Now, if you want to get super geeky, starting the cool water into the coil at the top, and removing the hotter fluid at the bottom, will yield a tiny bit of improvement. But only if you aren't stirring the wort....

 

[Bobby_M]

You'd be amazed how fast water convects heat. Yes, in theory the wort closer to the coil will be cooler but only very, very slightly.

Actually it's in theory and in practice. Test it for yourself like this; Leave an IC in an undisturbed pot of wort and run it for 1 minute. Test the temp of the IC output water or even just feel it yourself. Now, have someone stir the wort while you're measuring the output water. You get a HUGE jump in temp. Temperature stratification is pretty common. Ever swim in a lake?

 

[the_bird]

I've played around with the wort chiller, stirring and not, leaving the flow constant. I've got a probe thermometer that stays in the wort, so I'm always getting a current reading. When gently stirring, I can see a stready, pretty rapid decline (it chills to pitching temp in about ten, maybe twelve minutes). When I stop stirring, it stops cooling - the rate of temperature decline is less than half what it was previously, probably significantly less than half.

 

[Philip1993]

You'd be amazed how fast water convects heat. Yes, in theory the wort closer to the coil will be cooler but only very, very slightly.

Actually, the wort closer to the coil will be significantly cooler. As noted in the posts above, the cooling is so significant that further cooling will stop unless something occurs that disturbs that gradient.

 

[98EXL]

/subscribed

 

[sharpstick]

I made a dual-coil immersion chiller, as I found the thin fridge tubing dirt-cheap at the Depot (when they couldn't tell me how much it was, they sold it for less than half price).

i went to lowes to get my own, but found 3/8" x 25' roll at $60. how come you can buy a completely made chiller for less than that?
bill keiser

 

[FlyGuy]

i went to lowes to get my own, but found 3/8" x 25' roll at $60. how come you can buy a completely made chiller for less than that?
bill keiser

Ouch -- I got mine for $20 CDN. I also got 100' of 5/8 copper tubing for $90. Maybe Canada needs to export some copper!

 

[98EXL]

hook it up, send it south

if you ship it to the states, put on the customs form "bong materials" that should get some laughs, hehe

 

[Chriso]

i went to lowes to get my own, but found 3/8" x 25' roll at $60. how come you can buy a completely made chiller for less than that?
bill keiser

Home Depot - at least in my city - overcharges something horrific. I went to a more-local franchise (Menards if anyone has one) and their copper prices are HALF of HD's

I need to drive south to check the Lowe's they just opened.