Heat transfer

[richlong8020]

Does anyone know, in approximation, the rate of heat transfer in copper tubbing. I want to build a cooler with a coil in it but don't want to go nuts and over do it.

I was thinking about one of those round igloo coolers you may see on job sites. Then 50' of 1/2" tubing coiled inside for ice and water to get the wort down to pitching range or lower.

Thoughts are always great.

 

[RM-MN]

Since the wall of the tubing is thin, you can consider the heat transfer nearly instantaneous.

 

[ChuckO]

Think more about the total amount of heat that must be transferred. Bring 5 gal. of 212 deg. wort down to 70 deg. and consider the volume of ice required. That's why a lot of people use counter flow chillers, there's a lot of heat to remove.

 

[govner1]

I'd put a small pond pump in the bottom to give you better circulation of the ice/ water mix. It'll be much more efficient.

 

[richlong8020]

I don't think I was clear with my question. I need to know the rate of heat transfer per foot of copper tubing. I need to know if 50' is too much or if it will cool the wort too much.

I think the cooler the wort the better. It can warm up to the right temps with ice baths and swapping out frozen bottles.

 

[nukebrewer]

Rate of heat transfer depends on the difference in temperature between the cooling water and the wort. I think what you want to know is the specific heat capacity of copper, which is about 0.09 Btu/lb-F. So it's more a question of what the mass of the copper tubing is rather than the length of it. Now, there's a bunch of fancy engineering calcs you could do to figure out how fast your wort will cool, but the general rule is that the quicker you can cool your wort, the better. Just stop cooling when you're at the right temperature. I don't think 50 ft is overkill.

 

[richlong8020]

Rate of heat transfer depends on the difference in temperature between the cooling water and the wort. I think what you want to know is the specific heat capacity of copper, which is about 0.09 Btu/lb-F. So it's more a question of what the mass of the copper tubing is rather than the length of it. Now, there's a bunch of fancy engineering calcs you could do to figure out how fast your wort will cool, but the general rule is that the quicker you can cool your wort, the better. Just stop cooling when you're at the right temperature. I don't think 50 ft is overkill.

This is good info. So 50' at 1/2" is good and that's what I was hoping to hear. I was planning for at least an inch of space between the coil and cooler wall. Plenty of ice and water to touch the copper.

I'm leaving the plug in place to drain off some water as it melts and add more ice.