I have one question on counter current

[Aotidae]

So I am thinking about making a counter current wort chiller, and while I was researching a bit, I saw a video where this guy wrapped copper in an inch a half spaced spiral around the copper tubing before running it through the pvc tubing. I think this seems like a good idea, but it also seems like it might be more hassle than it is worth. I think it would provide more of a conductive surface area, but I feel that would only help by a degree or so. Would anyone think this to be a good idea?
This is what I am planning on using so far:

1. http://www.homedepot.com/p/t/100155...&productId=100155676&R=100155676#.UeGuw9Ism8A

2. http://www.homedepot.com/p/t/202270...&productId=202270600&R=202270600#.UeGuztIsm8A (2 of these going to remove the outer layer of lead using the palmer method)
3. http://www.lowes.com/ProductDisplay...&catalogId=10051&productId=3132685&cId=detail

I plan on using gravity and not a pump. If this is not a good idea I will stick to immersion for now.

 

[ajdelange]

Not only does the wire increase the thermal cross section between wort and coolant but it insures the flow will be turbulent thus increasing effective thermal contact. This concept is carried further in the wort chiller sold by Hearts (http://www.heartshomebrew.com/index.php?main_page=product_info&products_id=878). This device is a condenser for a water cooled refrigeration unit (hot gas from the compressor flows through the center and water through the outer circuit). These really do a fantastic job for the size.

 

[tyzippers]

If I understand you correctly, the purpose for wrapping the copper tube with a (I'm guessing) copper wire is not for extra surface area. It's all about creating turbulence in the annulus around the copper tube carrying the wort. That gets more of the cooling water in contact with the copper tube which increases heat transfer. How much, it's hard to say without me getting my fluid dynamics and thermodynamics books out. So, is it worth it, it all depends. It might save you a few minutes in cooling time, so you can make your own choice there.

 

[DaleHair]

I think a better option may be to put a slight crimp in the tubing every few inches before inserting into the outer tubing, this would cause both the wort and the cooling water to have turbulence. However when you coil the thing up it may kink the tubing.

 

[Aotidae]

So the wire would create turbulence which I am guessing creates a circular exchange between each bump created by the wire, which should increase the counter exchange?
I think it would be about $7 extra to do this. Seems worth it I guess.

 

[ajdelange]

The most I'd be willing to say is that it prevents laminar flow so that more of the coolant actually comes into contact with the outer surface of the inner tube.

 

[outside92129]

I did that on my CFC, it worked great. Did it help? I didn't make a comparison unit to benchmark. But the unit worked so well that i could run my pump full-open on it and the wort came out at 70F. Unfortunately i mounted it too close to my BK burner and overtime the PVC degraded and developed too many leaks to deal with. I switched to a plate chiller but i do wish my CFC never died.

Btw, i soldered the outside wire ever several inches so it wouldn't move as i slid it into the PVC. The wire also keeps the copper coil centered in the PVC tubing and surrounded with coolant water, i can see how the tubing would want to go closer to the center as you coiled it. And with the extra wire it became really hard to complete assembly as it added quite a lot of resistance during insertion.