Water(less) Wort Chiller

Mountainbeers · 11-27-2009, 10:06 PM

So I've been getting ready to go AG soon and I am amazed at the amount of water these chillers go through.

Yea yea I know what you're going to say..."Recycle your water!"..."Recirculate your water!" Well I'm willing to do that but only if I can't find an easier solution first.

I started trying to think of a design for a chiller using ice. The problem with ice baths now are that a) they melt too fast and b) the heat (energy) isn't taken away like it is in water in say an IC so it takes too long.

Now for the boring part. Hang in there.

The general heat transfer formula is:

1/UA = 1/h1*A1 + (dx/KA) + 1/h2*A2

U = the overall heat transfer coefficient (w/m^2k)
A = contact area (m^2)
k = thermal conductivity of material (w/mk)
h = individual convection heat transfer coefficient for each fluid (w/m^2k) (this depends on the type of fluid and the velocity at which it is moving)
dx = wall thickness (m)

So in general, in order to increase your heat transfer you want to:

1) Increase the amount of contact between the fluids. (A)
2) Decrease the thickness of your copper wall. (dx)
3) Increase the speed at which the fluids move by each other. (h)
4) Increase convection coeff. (h)

With the below design you would be keeping the same k and dx because you are using copper tubing. The only common material with a higher coeff. than copper is silver. And this obviously isn't practical. Ice would fill the cavity (which would be closed off on the ends) and melt down through the holes. The ice conducts heat about 4 times more than water.

Has anybody tried anything like this?

**Bobby_M** · 11-27-2009, 11:08 PM

I'm not quite getting what that object is supposed to be. Is it a U-shaped copper tank? There really isn't a way to get enough ice directly into a batch and have it work well. Pol recently worked out how much total ice you need in a closed system and I think it was something like 40 pounds. Search for closed chilling.

Think of it this way, most water companies charge less than a 1/2 penny per gallon. Even if you used 100 gallons to chill, that's a whole 50 cents.

**ReeseAllen** · 11-27-2009, 11:40 PM

Yeah, I'm a bit puzzled by your 3D model screenshot. A couple of 2-D sketches, labeled, would probably convey your concept a lot more clearly.

AN_TKE · 11-28-2009, 12:09 AM

It looks like this is a rendering of a square copper bucket with the sides cut off. The ice is put in the bucket and allowed to drain as it melts. I am guessing the bucket is square for benefit of surface area to volume ratio. I think this an interesting idea that could be on the right track to having a water(less) wort chiller, but it looks like there may be problems found in draining the ice - where does it drain to - and you will need a pretty big kettle with a lot of freeboard to submerge this thing.

I like the large surface area, small chilling mass idea though. I imagine a copper cube that will fit a bag of ice and a bunch of copper tentacles extending from the ice chamber out into the wort. Then you'd need to replace the ice when it melts throughout the chill. With enough brainstorming maybe you'd stumble on something simple enough to actually incorporate into your brewery.

Mountainbeers · 11-28-2009, 12:23 AM

OK so I guess I didn't explain well. It's just a container of any type of material that is enclosed but the sides are cut off in the picture so you can see inside. The tube going through it is copper. The container is filled with water and frozen into a block of ice. Wort is siphoned/pumped through the tube.

I wasn't worried about the cost of the water as much as the environmental effects. The last two summers here in NC we have been on water restrictions because of drought. I just hate waste in any form.

ikonis · 11-28-2009, 12:25 AM

That makes a good bit of more sense. Maybe you're on to something.

rkw216 · 11-28-2009, 12:30 AM

How much energy will you use to freeze that much ice?

**conpewter** · 11-28-2009, 12:49 AM

Right I think no-chill is the most environmentally friendly way to get wort to room temp. For fast cooling a regular chiller is next best with re-using the water for another application since it is still clean. I do laundry with my chiller water and also save it for clean-up.

Mountainbeers · 11-28-2009, 12:59 AM

Quote:

Originally Posted by rkw216

How much energy will you use to freeze that much ice?

Guess it just depends how much I need. I don't know how big the container would be yet.

1 gal of water is 3.79 kg
spec. heat cap. of water is 4186 j/kg-K

What does water come out of the tap at? 60 F? That's 15.5 C.

Q = m*c*deltaT

Q = (3.79)(4186)(15.5) = 245,906.57 J/gal

245,906.57 J * 2.7778×10^−7 = .0683 kw-H

Average cost of electricity in April 2009 $0.12/kw-H

$0.0082/gallon of frozen water.

You better come back to this thread after all that work haha.

Suriel · 11-28-2009, 01:13 AM

Quote:

Originally Posted by Mountainbeers

Guess it just depends how much I need. I don't know how big the container would be yet.

1 gal of water is 3.79 kg
spec. heat cap. of water is 4186 j/kg-K

What does water come out of the tap at? 60 F? That's 15.5 C.

Q = m*c*deltaT

What I remember from my Heat Transfer Classes in College is that Q= U*A*Delta T log mean. If your looking for a better heat transfer you'd want to look at shell and tube heat exchangers or plate and frame. Really the key is to maintain a high temperature driving force to ensure heat transfer.

CA