Fan in Cupola

[BC Birch Tapper]

Has anyone ever put a fan in a cupola to assist in steam extraction?
I've got a 2x6 evaporator centered in the middle of the sugar shack with a
2'x2' cupola right over top.

I don't have steam hood, I got some quotes & they started around $1800 so it was a bit too pricy for me right now.
I have a tin roof and after things get rolling I get condensation on the inside of the shack which is a bit of a frustration.

I've also thought of making the cupola longer, say 2x6 to match things better.
Any thoughts? Thanks

[Clan Delaney]

Two things come to mind. First, I've read over and over that your cupola size should be at least as big as the size of your evaporator pans. I'd venture even farther to say that it should probably be as big as the working surface area of your pans (pans with flues will have greater surface area). That should take care of your steam venting issues. Second, I've also read that a fan could just make your problems worse. Fans need to move a large volume of air out of your shack to work. The replacement air needs to come from somewhere, namely outside. Now you're pulling cold air into the shack which will cool the hot steam that's naturally trying to rise, and cause it to fall. Water, even water vapor, is heavy. You'd need a powerful, steady upwards air current to carry out water vapor that's trying to fall.

[Flat47]

Clan - you bring up a very important point: rising air needs more air below it to replace it. Somewhere I have a sugarhouse design book that talks about air displacement. Like Clan said, rising steam needs air coming in under it to create a natural convection column (warm air rising and drawing in colder air beneath it, which gets warmed and rises and the cycle continues until heat is removed).

I'd try opening a window a little bit to add air into the sugarhouse and see how that goes. A bigger cupola will help, too.
I have seen sugarhouses with exhaust fans in the cupola (mounted vertically pointing out the cupola doors), so it's been done. Might be costly, though, but do-able.

[KenWP]

I see the old sugar houses here with the cupola with the doors that open up and the other day they were boiling and the steam must have been a 100 feet in the air. Thats how I found the one sugar bush as its hidden from the highway untill you spot the steam.
You would not need to spend 1800 bucks for a fan. Go to Princess Auto and they have barn fans for a lot less money. I have the catolog here and they list a 24 inch single speed 4255 cfm fan for $289 and a 2 speed 18 inch for $299 so you don't need to invest all that much money. A explosion proof fan is only $569 and there is not dust in a sugar house so hardley needed.

[Roads End]

Have you looked at your local Home Depot? I know they stock attic vent fans in the one by me up to 36" in diameter and for less money thenyou had mentioned

[Clan Delaney]

Have you looked at your local Home Depot? I know they stock attic vent fans in the one by me up to 36" in diameter and for less money thenyou had mentioned

I'm not sure an attic vent fan would hold up for long when exposed to the moisture levels of a sugar house. Add to that the freezing nights... That fan could end up being a one season purchase.

[tyrod2]

Paying for moore electric will just cut down on what you will make on your syrup.That is why you don't use a electric water heater to preheat your sap.
Thay just raised my eletric bill again.

[802maple]

A longer cupola for sure and also cover your tin roof on the underside with boarding or plywood and that will help on the condensation on your roof.

[KenWP]

I can't read while watching my evaporator on a cool day or at night as I get rained on and the pages get soaked.

[jrthe3]

i have the attic vent fan in my roof that is all it has been five years now still going strong just wish i would of bypassed the thermo switch

[PerryW]

cover your tin roof on the underside with boarding or plywood and that will help on the condensation on your roof.

Ditto to that comment. If you just use strapping with a metal roof, you will get drips because the steam directly hits the metal and condenses. Just take the metal roofing off, and completely board up the roof, and reinstall the metal. If you used screws, it isn't as much work as it sounds.

[woodshillmaple]

I used to get a lot of condensation too even though my cupolo is plenty big enough. I bought a roll of tech foil, the aluminized bubble wrap, and stapled that to the ceiling joists. It helps to insulate the roof that way in itself plus created an area of dead air between the tin and foil. It works great and was easy to install.