Insulating a Single Wall BBT Tank for use as an HLT

[Jephro]

Suppose you have a 30 BBL single wall BBT and you want to put a heating element in it to use as a HLT.

-How would you insulate it?

-What would you use to insulate it?

[beermkr]

Spray foam....

I built a CLT out of a plastic tank wrapped with PEX tubing and sprayed with 4 inches of foam. We had an commercial insulation company come in and do it.

We ended up with a very ugly contraption that we covered with a faux wooden barrel. The barrel is clamped together with copper bands and is cool. Pictures can be seen at my Blog site:

https://www.pensinger.net

Mike

[gitchegumee]

Sure, sounds simple enough, right? It can be done. It might not be cheap. First, the insulation is the tough part. Low chloride, high temp, stainless-qualified insulation is a must for longevity. Then a total surround stainless cladding is nice over the insulation to keep the tank nice and shiny, to keep any moisture from robbing heat, growing bugs, and being a nuisance. That's the pricey bit. Otherwise, on the cheap you could insulate with closed-cell neoprene held on by a contact cement product called "gorilla snot", and call it done. I don't recommend that option. An overflow standpipe from near the top of the vessel to the house drain for possible overflows is good. A large vent on top for release of gases and to relieve yourself of any ASME requirements. Weld in a stainless 1 1/2" half-coupling near the bottom and screw in your new element. It's not crucial what type of element you have, as long as you don't dope your sparge water with acid. If so, go with Inconel. Get it as long as you can, though. Lower Watt density may lead to longer life. Use the bottom fitting as a drain and pull hot liquor above this, if you can. And then a float switch above the element as a permissive to your heater circuit to prevent dry firing of the element. That will probably save your ass more than once! Size your element per your Hx efficiency. If you can get 85 degree water from knockout, then your load is small if you brew every day. If you have less efficiency, or brew infrequently (or on the spur of the moment), then you may need higher kW rating. I currently have a 5kW heater on a 10hl system that performs just fine. If I don't brew for a week, I do have to start the heat about a day in advance to get 1,200 liters to 80 degrees, but I can manage that. That being said, a 10kW heater isn't that much more. Good luck and I hope you can make it work!

[Moonlight]

I found that sheet styrofoam insulation can be bent by strapping it to your kettle. Once warmed and curved it relatively keeps that curve and can be strapped to your round tank. Two or three layers of 1" styrofoam could do it. (overlap seams of successive layers) The dished top and especially bottom could be more challenging.
Another option for an outer wrap is sheet aluminum. Relatively cheap and easy to work-rivets or short screws could even hold it together at the overlapping seams. Caustic and such would make the finish look ugly, but even that could be painted.