Finned heat exchange tubing for a counterflow chiller?

I had an idea of building a counterflow chiller using copper tubing with fins (like for water baseboard heating). I was thinking to use pvc pipe for the outer water flow. I was just wondering if this was practical. The tubing has those nifty heat exchange fins but it usually comes in a pretty large diameter. Has anyone done this or seen anything like it?

I tried it. The piece of 4" sched. 80 PVC I used is back to serving as a rain spout extension. I couldn't make it work well enough for it to be of any use. I only played around with it for a couple of hours after work one night.

I just can't think of an inexpensive and effective way to get the cooling medium (water in my case) to flow over the fins. I would imagine there is a way to use this tubing but it would probably require a more elaborate set-up than would be practical. Keep me/us posted on your progress if you continue this project.

I think it would work great if it had a heat sink style fins that went with the pipe. Only thing I can think of is that schedule 80 pipe with a manifold injecting the cold water from multiple sights along the pipe with a single exit point for the water.

Yeah, the problem with that construction is that the fins are oriented to heat air that flows perpendicular to the copper. I know there is copper that has a helical fin wrapped, but I'm not sure it's available as a raw material.

I don't think a radiator tube like that would work well. There are coolers known as laminova cores that are made out of aluminum. They have a massive amount of surface area for their size. They are used for oil or supercharger coolers in race cars. They would work great if you can afford them.

What if you packed the outer tube with ice?

I see the same problem others have. If you have that inside another pipe with water flowing in the opposite direction of the fins, you will get poor results. The fins are oriented the wrong way for that use, the water will simply go around. If you build a more complex rig where the water entered from the top and exited from the botom, traveling between the fins, it might work better. Still that is a lot of work.

Makes sense, I just had a bit of this I could get for free but it might be more trouble than it's worth.

One way I was looking at it is to have the pipe with the fins in a rain gutter that is sealed at both ends and fill the rain gutter with ice water. That could maximize the contact with the fins and pipe without having to build some contraption to move the water across the fins.

Yeah but the ice will melt fast and then the water warms up and you've got nowhere to go from there.

Yep, hopefully it's cooled to where you want it by then.

Unfortunately not with 5 gallons of boiling wort. It takes some 40 pounds of ice to pull that kind of heat out.