Why Tunnel Fans with Butterfly Shutters may not be a Good Investment?
Published:January 23, 2015
Summary
Figure 1. Damaged fans with butterfly shutters For decades, the “slant wall” fan was the preferred poultry house exhaust fan (Figure 2). Testing found that by simply moving a traditional exterior panel shutter (Figure 4) to the intake side of the fan, the air-moving capacity of the fan was increased five to ten percent. Furthermore, the interior fan shutter location resulted in ...
Good article. I ended up with butterfly shutters on a new site without a discussion from the contractor of the options.
Have you done any work on a way to insulate the butterflies and or fan shrouds to save energy and reduce condensation?
I have problems with butterflies freezing up and not closing correctly in very cold weather. High wind is also a problem. Poor design in my opinion, but now I’m stuck with them.
Steven Nisly It is a weakness of all butterfly shutters. There are fans with motorized butterfly shutters which solves the high wind and sealing issues, such as the Skov Blue fan. The doors are not super insulated but they do have an insulation "disk" that winterizes the fan very well. It is also a variable speed fan. As you might expect it is not inexpensive.
Dr. Mike Czarick you may also have a look at DACS that makes a motorized insulated door, called MagDoor, that you install inside the barn. With a exterior fan cover for winter should be good to go. Probably not the cheapest way upfront, but figuring how much energy is wasted + fan corrosion, it may be well worth.
Here in Quebec, as most of other Canadian provinces, because our winters are very cold, we use interior shutters that we replace in cold weather with a interior insulated rigid closure panel. Maybe you could add a framing around up your fans and add this kind of panel ?
Good luck