CFC concept

[Matovichi]

So last night I had an epiphany. I'm not very good at describing what's in my head, so ya'll will have to run with it. My idea is to get some 5' or so of 3/4" copper tubing (straight, not to be curved) and filling it with marbles. Now I have not lost my marbles, but hear me out. Assuming you build the cfc around the tube filled with the marbles as normal, I think it will end up with some fairly decent cooling for much less than it would normally cost. My logic is that the marbles (which tend to be 1/2") will more or less force the hot wort to the outer portion of the copper tube, the side that's doing the heat transfer. If you had a long row of these marbles it would, in my theory, cool off wort fairly well. Now the 5' was arbitrary, but 5' surface area equals out to 11.775sq.ft., which is the same as what I currently have (1/4" approx 15' long) Now my current chiller probably has about 5 or so extra feet of tubing that wouldn't be required (I currently get from 212 to 60 with heavy condensation on the "entrance" end of the cold water), so I figure that equals out to 7.85 sq.ft. and 3' of 3/4" would be 7.065. I think I could get away with a 3' chiller.

Now all of this is hypothetical using math only to calculate the surface area of the tubes. Since the marbles increases the volume of wort in contact with the copper, I think this would be the main thing to consider. I really just wanted to hear what you all had to think about my concept. I plan on trying it out soon, since it really shouldn't be too hard to build. And it ought to be relatively cheap, since a 10' piece of tubing is 16 bucks, I plan on using pvc as the jacket so maybe another 5, and then some plumbers putty for sealing, so another 2.

 

[drunkatuw]

First problem would be trying to find a 1" hose to wrap around the 3/4" copper tubing.

Maybe along the same line you could do something like a 1/4" copper tubing with the ends soldered closed inside of a 1/2" copper tube inside of a 3/4" garden hose.

 

[King of Cascade]

If the marbles are 1/2 inch and the tubing you want to use is 3/4 inch it leaves you with 1/4 inch of transfer area. Why not use 1/4 inch tubing and skip the marbles.

 

[beerthirty]

I think the marbles would hold a lot of heat so you would be trying to cool them down also. the further down the pipe the cooler the marbles would be but they would also slowly heat up. I think what you are trying to do is cooling the wort by providing more surafce area to the wort. Now if you ran a smaller pipe down the center of your 1" pipe and sealed it from fluid transfer from the outer pipe, you could run coolant through the center pipe, but then toy would need a larger pipe to go over the wort pipe to run coolant also. 3 pipes with the inner and outer running coolant while the middle one ran the wort. sounds a bit more than I want to get into. check out my CFC here https://www.homebrewtalk.com/showthread.php?t=73315&highlight=hell+earth I gave it a test on real wort sun. boil to 72* single pass, 15 min, 10 gallon, 20 lbs of ice

 

[the_bird]

If the marbles are 1/2 inch and the tubing you want to use is 3/4 inch it leaves you with 1/4 inch of transfer area. Why not use 1/4 inch tubing and skip the marbles.

Hmm... you could split the wort into three or four lengths of 1/4" tube, which would then travel down the length of the PVC.

 

[k1v1116]

Hmm... you could split the wort into three or four lengths of 1/4" tube, which would then travel down the length of the PVC.

I think that's called a "shotgun condenser" in distilling. the hardest part would be building the manifold to split the wort evenly into however many streams.

 

[Brew-Happy]

Why not flatten the 3/4" tubing to the same thickness as 1/4" to expose the wort to a larger surface area. Heck, you could flatten it even thinner.

Of course leave the ends round to connect.

Just a thought.

 

[Bobby_M]

Now the 5' was arbitrary, but 5' surface area equals out to 11.775cu.ft.

Surface area is measured in square inches, feet, meters, etc, not cubic. Cubic is a measure of volume. 5 feet of 3/4" ID tubing is just under 1 square foot of surface area. It's diameter x 3.14 x length (makes sure the D and L are the same units) so .75" x 3.14 x 60 = 141 sq inches.

You're right in that your current tube has the same surface area.

I understand the concept, more surface area per length. It's an alternative to the multi-tube exchanger (picture like four 1/4" OD wort tubes down the center of a 3/4" coolant jacket like the_bird said).

The multi-tube system is a little tougher to build but it's predictably more efficient. Take this example:

25 feet of 3/8" tubing (.25" ID) has a coolant surface area of 353sqin. The cross sectional area is .078 sq.in.

If you took THREE lengths for 1/4" OD (.19" ID) tubing, that has a cross sectional area of .088" which should flow a little better than the above, but now has a coolant surface area of 708 sq.in.

So, it's 100% more surface area for the same length or the potential for 1/2 the length for the same cooling. There's also the advantage of being able to give the three tubes a gradual twist to keep the coolant water turbulent. I'd go with 3/4" PVC as the Jacket, or 3/4" hose.

After all that, you're still screwed if your tap water is over 75F.

 

[Matovichi]

I should have probably mentioned the other benefit I see in using marbles (I told you all I was bad at describing what's in my head). This is kinda a twofer, the first being that the shape of the marbles allow turbulence, but shouldn't slow the flow of the wort down nearly as bad as using 1/4" tubing (soooo slow!). The other benefit is the fact that the marbles do absorb heat, laboratories use glass condensers and glass refluxers. The main point is that glass transfers heat just about as well as copper, and while it may hold heat, the marbles down by the cold water will remain cold. The main goal of this isn't to make a high tech nor a complex cooler. Just a cheap, effective one that could cost less to do than making an immersion chiller. Also, there ought to be more than 1/4" of available space, because of the shape of the marbles. Hopefully, that would allow the wort to travel faster through the chiller than 1/4" tubing would.
Bobby, nice catch, I kept typing that, but I tried to correct myself. Obviously, I missed one.

 

[John Beere]

First-ly, welcome. Second-ly, while I admire the inventive spirit, I don't think 5' of anything is going to be enough to bring boiling wort down to pitching temperature - regardless what you do to it.

 

[Bobby_M]

Three 1/4" tubes in parallel should flow more than a single 3/8" tube. Give your idea a try and let us know how it works out. Document your tap water temp when you test it out because it is the most influential variable in any chilling results.

 

[Matovichi]

Will do. FWIW, I use a ice water bath that feeds my current cfc via an aquarium pump. It's not a very fast pump, but it certainly gets the job done. I noted a 20*F difference between using tap water and using the iced water. Plus using my bath (very large laundry bin) I can actually have the hot water 'recycled' back into it, since hot water will stick to the top. The pump I use is mounted on the bottom of the bath to ensure that cold water goes through the pumps.

 

[Skrimpy]

Well...it sounds a little bit like what the chillzilla does but the opposite. (Note: for those that don't know, the chillzilla causes turbitity in the water making it take on heat more efficiently, thus cooling the wort more efficiently) It sounds like you will make the wort a little more turbid but I don't know how this would help since the marbles would also take on some heat most likely decreasing the efficiency. Your idea has sprung one in my mind to help you but I don't know if it would be worth the work, but here goes.

How about three tubes instead of two? You could take a smaller copper tube and place it inside your wort tube and also pass cold water through that in the opposite direction to the wort. Finagling the logistics in getting the water into it is not really something I am willing to think about at the moment, and I am sure someone will tell me if it is, or isn't possible and the pitfalls of doing so, and how one would go about doing it because why? We got a lot of friggin smart people here. My guess is that it could approach 1 1/2 to 2 times the effieciency of just two tubes. The upsides would be the benefit you were mentioning with the marbles. You would increase the cooling surface area, thus increasing the contact area for the wort. Then what you could do is do things to make the water more turbid in the outside water tube (maybe welding a copper wire spiral around your wort tube) and also the inside water tube (ie just put anything you can find in it...screws, nuts, bolts, marbles). Don't ask me specifics about size, it's late and I'm not willing to think right now. Sounds do-able to me, but after 10 beers anything is do-able.

 

[Matovichi]

Right now I'm in the process of acquiring all the stuff I'll need, but I'm having some 'second thoughts' if you will. Not second thoughts in the usual sense, but rather, incorporating what you all have told me thus far into my design. I don't know if it's because I just got off work at 6 in the morning and have already had a beer or 3 (stressful "day"), but what if I take my idea, and sort of invert it. Instead of having the hot wort going through the center tube, what if I flipped it. I made a whoopsie when I bought my copper and my pvc, and have very little actual space for any coolant to travel through, so this also has to do with my alterations.

My new thought is to buy 1/2" copper tubing, and insert it into the 3/4" copper. Then sealing it off like a typical cfc, albeit in a straight line. From there, continue my thought of adding marbles into the 1/2"er (my marbles are probably 1/4", much smaller than anticipated), this is mostly to just 'force' the coolant to the outer perimeter. I suppose if I got some copper wire, I could lace the 1/2 inch with it to create some turbidity in the 3/4" tube. So essentially, the hot wort travels around and against the coolant and if possible also run the coolant through the pvc jacket. I plan on keeping the jacket regardless mostly as a safety precaution. My only issue with that is the pressure required to run both the inner tube and the outer tube at the same time my not be enough from my little pump. Another 'perk' of this idea would be the marbles would still absorb heat, but they're being directly cooled by the coolant. Sort of like having a heat sink. Even though the difference of the two is 1/4", which is what I currently have, the total volume of the 5' concept is approx. 6cuin larger (total volume of usable wort space = 14.715cuin and my current setup is roughly = 8.83 cuin) Therefore, I ought to have a higher rate of flow than I do currently.

Any thoughts on my new idea?

 

[sigmund]

Since the contact between your marbles and the 1/2" copper will be minimal, heat transfer will be little. You'll still be heating the marbles up but you aren't going to get the cooling you think you will. Good luck and keep us updated.

 

[Bobby_M]

Surface area is more important when turbulence is low and you can acheive surface area in many different ways. In the typical 25' CFC, we use length because it's cheap and easy. A plate chiller uses a complex design and manufacture to shrink the surface area down. I still like the idea of tripled 1/4" wort tubes inside a single jacket. I'd solder them in to 3/4 inch end caps where three holes are drilled.

 

[the_bird]

I have a bunch of parts left over from when I built by dual-coil chiller; I may futz around and see if I could put something together, either three or four wort tubes. Wondering if there would be any benefit to jacketing it with copper, so that you could then immerse the whole thing in ice water and pull off even more heat.

 

[Skrimpy]

Surface area is more important when turbulence is low and you can acheive surface area in many different ways. In the typical 25' CFC, we use length because it's cheap and easy. A plate chiller uses a complex design and manufacture to shrink the surface area down. I still like the idea of tripled 1/4" wort tubes inside a single jacket. I'd solder them in to 3/4 inch end caps where three holes are drilled.

He's probably right. If you're going to increase the surface area it probably doesn't really matter how turbid the water is. At the point your cfc is 25' long it probably won't make a huge difference in how cold the wort gets whether you used the marbles for turbidity or to increase surface area. It will probably be as cold as it's going to get well before it comes out of the tube so...yeah, surface area is probably easier to do than turbidity and not that expensive. I'm going to make one with 25'-50' copper coil I have in the basement (left by the previous homeowner in my new home). I hope there is enough to make two. I'de like to sell one like Bobby did to recoup any costs.

 

[Bobby_M]

I have a bunch of parts left over from when I built by dual-coil chiller; I may futz around and see if I could put something together, either three or four wort tubes. Wondering if there would be any benefit to jacketing it with copper, so that you could then immerse the whole thing in ice water and pull off even more heat.

I'm sure that's one way of eliminating the icewater pumping. I have some 3/4 refrigeration tubing that I might try that with. I wonder what kind of radius I could pull on it by hand.

 

[Matovichi]

So I completed it, and wound up with the conundrum of having to chose between running the hot wort through quickly, which did cool it albeit not as efficiently as hoped, or run the wort slowly to get to the temperature I want, but it's still painfully long that way. If I did run it fast, I could get from 212 to about 140 in about 10 minutes. Not spectacular, but still would slow any dms and whatnot, however I would have to recirculate it manually (dump the wort back into the boiler to recool). I'm not too fond of that idea. Running it slow was about 45 minutes to get to 70 with recirculating ice water in the chiller. This might be more effective had I gone with 10' instead of 5', but that would take up far more space than I'd desire. While it was a very minor success (I tried it without marbles and the temps were much higher (170-180), with about 2 minutes less running time) I have chosen to abandon the idea in favor of a recirculating IC. Of course, I need to make that project much more complicated than it needs to be, and I'll probably ask for help later.

 

[Special Hops]

Heat transfer is all about surface area between the hot and the cold. The marbles will create some turbulance which will help, But once the marbles are hot you would loose any efficiency you gained.