12' Wort Chiller?

Would a 12' Stainless Wort Chiller be efficient enough for a 5 gallon setup in a kitchen sink?

Yes.... IMO

It'll be better than nothing.

Stir it a lot while you're cooling, and you should be fine.

This time of year, you'll be fine because of the COLD tap water...but if/when that warms up you may have to wait a while for the wort to get down to pitching temp. Not sure about CT in the summer, but around here our tap water get's up to 85F.

Do you have a good deal on stainless because copper transfers heat better. I know some people dont like the copper, but I have a 15ft copper chiller and it works great. I have one of those big blue tubs for kegs, I put my brew pot in there, then I hook my hose to the chiller, then use a small piece of hose from the discharge into the tub. Then I use another small piece of hose to siphon out of the tub onto the ground. With the hose at 3/4 the disharge is still pretty cold, so the water in the tub cools the outside of the pot as well. Kind of a 2 stage cooling system.

EDIT: I just reread you post and saw it was in your sink, so my setup wouldnt work, but I think copper is still better for heat transfer.

OK, I've got to do it now.

Sometime this weekend I'll do the calculations for convection on the inside and outside of a chiller and set up the resistance network to show how minimal the higher conductivity of copper matters. It's all about the convection guys.

BTW, this is ALL I thought about through my entire heat transfer course I just finished up.

hammacks said:

OK, I've got to do it now.

Sometime this weekend I'll do the calculations for convection on the inside and outside of a chiller and set up the resistance network to show how minimal the higher conductivity of copper matters. It's all about the convection guys.

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Be sure to factor in the dramatically thinner walls of stainless tubing. I've got both a copper and a stainless chiller of about the same size...the stainless is a fraction of the copper ones weight, light as a feather. Both seem to work about the same.

Of course lemon but...

It is possible that the extra thickness of the copper benefits heat transfer. How? More surface area. I wont know until I crunch some numbers to give me some realistic convection rates.

Case in point, contacts actually cool your eyes. They insulate some conduction, but they create an increase in surface are for convection.


But anyway I will probably use 32 thou for the copper and 20 for the SS.

hammacks said:

It is possible that the extra thickness of the copper benefits heat transfer. How? More surface area. I wont know until I crunch some numbers to give me some realistic convection rates.

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How do thicker walls get you extra surface area? Given the same OD, thinner walls would actually translate to slightly more surface area on the inside.

BlindLemonLars said:

How do thicker walls get you extra surface area? Given the same OD, thinner walls would actually translate to slightly more surface area on the inside.

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Seems that way to me to FWIW.

Pipes are measured by their ID. So same ID, bigger OD.

hammacks said:

Pipes are measured by their ID. So same ID, bigger OD.

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Copper tubing is sold by OD, with varying wall thickness.

Yup OD on copper, but really, the difference we are talking here, is it even worth the effort to calculate transference rates for an IC?

Laughing_Gnome_Invisible said:

Yup OD on copper, but really, the difference we are talking here, is it even worth the effort to calculate transference rates for an IC?

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Define "worth" for me! All in the name of scientific curiosity, good sir.

Exactly when did you go invisible?

BlindLemonLars said:

Define "worth" for me! All in the name of scientific curiosity, good sir.

Exactly when did you go invisible?

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Definition of "worth" :- Math induced headache V. Exact knowledge of extremely minimal difference = Not "worth" the trouble

I went invisible about a week ago, but nobody noticed because I was, well....Invisible! Just a little FYI, I am not English invisible, I am French invisible, Pronounced ang-vees-ah-bluh......It's a music related thing, which I'm sure that someone with a user name like yours would fully understand.

Laughing_Gnome_Invisible said:

Yup OD on copper, but really, the difference we are talking here, is it even worth the effort to calculate transference rates for an IC?

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Ah thanks for the correction guys. I could have sworn it was by ID.

As far as worth it: I'm sitting in class on the first day and the professor is mentioning all the things heat transfer knowledge is useful for. One of the things he says is brewing. Well it's been bothering me since. Also, copper is often called superior whenever someone asks for purchasing advise. Whatever the case may be, Brewers spending their cash should know if that's true or not eh?

So you guys pretty sure both SS and Cu are going to be the same OD? I'll take your word for it.

For a given listed size, considered apples-to-apples (ID and ID), the walls in SS are going to be thinner. For the size of tubing we use in homebrewing, the few thousandths of an inch doesn't matter.

Having been through much the same class back in the day, the thickness of the metal walls doesn't matter much when you're talking about brewing applications. The five components of heat transfer (five different heat transfer coefficients / R-values) are wort-to-wall (driven by turbulence and thermal conductivity of wort), scale on the inside wall (which will have thermal conductivity one or two orders of magnitude *worse* than the tubing, the resistance of the tubing (orders of magnitude higher than the wort/water-to-wall, scale on the outside, and wall-to-water.

You can drive up heat transfer coefficients on the liquid sides a factor of 10 or so by getting into turbulent flow; that's why some coolers advertise having turbulizers inside. In theory a badly-scaled chiller will fail to transfer heat well; this is a known phenomenon inside industrial boilers, your water heater, and things like that...industrially, scale is dissolved with acid to ensure good heat transfer. Granted, the consequences of scale can be explosions, not a couple extra minutes spent chilling wort.

The only time that tubing material would be a factor would be in a condenser (because the heat transfer of a condensing vapor is one to two orders of magnitude higher than flowing liquid. If the heat transfer coefficients of the working fluids are very high, worry about the metal. If not, just keep your equipment clean and you'll be fine.

One reason to use copper is that it's easier to bend and solder...and still fairly resistant to corrosion. It's more expensive on a per-lb basis, and not as strong...that's why most modern industrial heat exchange equipment is stainless. When you're holding back 2000 psi, you need to worry a lot about tube thickness.

I have no idea about ss, but copper is definitely measured OD. It's how we know what fittings to buy......So I'm guessing ss will be the same. ID is pretty much useless info when buying fittings


And yeah, I would get obsessed too if I had your teacher!!!

Copper tubing is sold both by OD and ID. For some reason the refrigeration stuff goes by OD. Then it gets more confusing that rigid copper tube is rated by nominal ID (1/2" nominal is 5/8" OD).

Bobby_M said:

For some reason the refrigeration stuff goes by OD.

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Well, it's for the reason the invisible gnome pointed out...standardized fittings that mate with the outside of the tubing. Otherwise, we weekend warrior handymen couldn't go to Home Depot and get what we need off the shelf!

Nice treatise on heat transfer, Scotty_g!

Bobby_M said:

Copper tubing is sold both by OD and ID. For some reason the refrigeration stuff goes by OD. Then it gets more confusing that rigid copper tube is rated by nominal ID (1/2" nominal is 5/8" OD).

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OK that's what it was. I was just working with rigid copper for tower cooling.

hammacks said:

OK, I've got to do it now.

Sometime this weekend I'll do the calculations for convection on the inside and outside of a chiller and set up the resistance network to show how minimal the higher conductivity of copper matters. It's all about the convection guys.

BTW, this is ALL I thought about through my entire heat transfer course I just finished up.

Click to expand...

So I was feeling guilty that I was a dead beat on this. The main PIA is getting a decent calculation for the convective heat transfer.

I have a heat transfer LAB course now and wouldn't you know it, this week I will experimenting with counterflow heat exchangers. I should be able to get a decent h value from that. I'm pretty sure I'll be doing a resistance model of the system that will illustrate the whole idea well. And now I have to do it (or I get bad grades ). My prof used to live in Portland and would take her students to microbreweries to see their industrial plate heat exchangers.

In the mean time, lookie what I found. Coefficient of entire heat exchange system (convection -> conduction -> convection)

Fluid-----Material-----Fluid------Transfer Coefficient ((Btu/ft2 hr °F) and (W/m2 K)
Water---Mild Steel---Water----60 - 70----340 - 400
Water---Copper------Water----60 - 80----340 - 455

Very rough, but based on the same velocity and flow characteristics for both so comparison between the two is valid. SS is similar to the mild. Point is, massive difference in conductive coefficients between steel and copper = very little impact on system.

Found it at a great reference site here:
Overall Heat Transfer Coefficients for some common Fluids and Heat Exchanger Surfaces
Look at how much better steam to water through copper than water to water (and that's not even considering the larger temp difference).

Heat transfer in a film of condensing vapor is very high as long as the condensate can get away. IIRC it's got to do with the thin film of condensate (relatively little insulation from a stationary liquid layer) and rapid transport of material from the bulk vapor to the cooling surface--as one volume of gas condenses to form 1/1000 a volume of liquid, 999/1000 volumes of gas are sucked in.

This doesn't have much to do with wort chillers anymore, but it's nice to find another thermo nerd out there (BS ChE from Wisconsin in '98).