Are your squirrel cage fans powered by the wind blowing through them, or are they electric, That is such a good idea!!
Quoting: Lil Sis My first attempt at inflation was with pure wind-powered inflation (I once saw a pic of an Amish fellow's contraption of that type), but it didn't work well enough, so now I use electric squirrel cage fans. The fan kits are ~$140 and use around 10 cents of electricity per day.
OP,
can you elaborate a little more on the double wall and inflating the greenhouse walls?
thanks.
Sure, here's how I set it up--
After creating the skeleton/shell (getting the pvc arches in place and attaching purlins across their undersides to give rigidity to the structure), I cover it with two big sheets of greenhouse plastic, right on top of one another, each one being big enough to totally cover the greenhouse by itself. I dig small troughs along the lengthwise (north and south) sides of the tunnel, place the extra plastic on those sides in the troughs, and bury it to hold it down and to make a fairly air-tight seal. On the ends of the tunnel (where I've built wooden end walls), I use small strips of wood that I screw down onto the extra plastic hanging over those ends, so that there's a mostly air-tight seal on the ends, too.
So at this point I've got the pvc skeleton covered by the two big sheets of greenhouse film, and the film is held down on the long sides by dirt and on the ends by small strips of wood screwed into the end walls. I then install the inflation kit.
The inflation kit has a hose that pulls air from outside (through a hole I cut in the wooden endwall), through the "squirrel cage" fan, and into the space between the two layers of plastic. This requires slicing open the inner layer of plastic and mounting the exit pipe in that opening, which the equipment then seals. Then, when you turn on the fan, it pulls air from outside and pushes it in between the two layers of plastic, causing the outer layer to bulge outward and the inner layer to bulge inward. The inflated space in between the layers (4"?) serves as a great insulator, and the rigidity of the outer layer (it looks and feels like an inflated balloon) prevents it from being whipped in the wind.
It's far simpler than my words make it sound! The pictures that come with the inflation kit make installation easy. Here's a YouTube video I found that might help to better convey what's going on:
