Originally Posted by rodduley
Hey microbusbrewery, this couldn't have been posted at a better time. I am in the process of trying to build the exact thing. I had imagined using an old cornie keg but this looks like it might be easier to work with. I also was going to just "drop in" the coil similar to a small wort chiller but I love the way yours goes through the walls. Could you please post a parts list and or any lessons learned during fabrication. Did you have any problems coiling the copper? any leaks? Have you tested the efficiency yet (ramp times)? Do you worry about any stratification? Sorry to question you to excess but I would like to know everything about this that is possible to complete my own build.
The copper wasn't too hard to coil. Copper work hardens so you just want to take it slow to make sure you don't kink it. It comes coiled and I started off slightly tightening the coil by hand, then I formed it around the crock of a mini-crockpot, then I formed it around a roll of duct tape for the final diameter.
As for leaks, the pot never leaked in my testing but I had a couple very small ones in the fittings themselves. These were fixed by tightening the fittings a bit.
Re perfomance, I just finished it last night so I haven't had a chance to brew with it yet. It's about the same size as my old HEX, so I'd expect the same performance. Both the old and new version use a 110V 1500watt element. In the past I've been able to a raise the temp by a little more than one degree F per minute. For example, if I was mashing at 154F and raising to 168F for mashout, it would typically take around 11-14 minutes to raise the temp to 168F. That's based on measuring the temp of the wort exiting the HEX. I'm going to brew a Pale Ale next weekend so I'll post back if I notice any performance differences.
As for stratification, I'm sure there's some but considering it's such a small vessel and that I'm measuring the temp of the wort itself as it's exiting the HEX, I think it's negligible.
Sounds like you found the parts list on Kal's site. He does a great job of stepping you through everything so I'd definitely recommend checking it out. Speaking of his site, the element enclosure is basically the same as his; an outdoor double gang box with 3/4" fittings.
The lid is just a basic Bain Marie lid. I'm going to try to find a flat saucepan lid that will hopefully fit it better. Here's a side view that shows the electrical box and you can kind of see the lid. I did a little write-up on my blog too, http://www.microbusbrewery.org/2013/03/heat-exchanger-redesign.html