03-01-2016, 12:18 AM
Thought I would post a project that I had been thinking about for years and when my shop furnace died for good I figured what the heck lets go for it and see how it works. Did a bunch of research and ended up talking with a guy who has designed and made a couple of these collectors that has been named a "Zero Pass" hot air collector. This particular design is different from most hot air collectors in that it is a forced air system vs a gravity/thermo-siphon. It utilizes 2 layers of screen placed with 1" between them that run down the center of the collector. Air is forced in one end of the collector then "funneled" through the gap between the screens. The screens acts as the transfer agent to move the heat from the black surfaces to the moving air.
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I was lucky enough to have a guy offer me a few sheets of tempered glass so I sized the collectors accordingly. The glass is 45"x76"x 3/16" thick. I made the frames from 20ga metal stud track. The back of the collector is lined with 1/2" foil faced foam board that is rated for heat. Inside the hollow of the track I ripped some 3/4" pine and then more of the 1/2" foam board. This combination filled the hollow perfectly.
The corners were made by leaving the end caps an extra 2" long then folding them around the corner and pop riveting in place.
Screen frames I made out of furring strips with some corner braces. Screen is regular fiberglass window screen stretched very very tight.
I mounted this unit on the south wall of my shop and ducted directly into the building.
Venting right into the building presented a problem. My whole south wall is cabinets. But as luck would have it I was able to modify the end cabinet for the blower assembly. I'm using the fan from my old furnace. It is a 4 speed fan so I hooked it up to run on low. It is a little oversized but not terribly. This thing needs a lot of air.
End result.
Just got it together the other day but so far I'm pleased. We had decent sunshine here this afternoon and it was blowing a steady 85 to 90 degree air all afternoon. I still have to order out a temperature controller for running the fan but for now I'm running it manually. This won't replace a furnace but it will sure cut down on the gas bill though. I expect to have about $250 invested in this by the time I'm done. If I didnt get the glass I was going to use a product called Twin Wall Glazing, Menards carries it for about $50 for a 4x8 sheet. Still wouldn't have been an extremely expensive project.
Lot of work left to due such as residing around it and flashing and adding a controller and adding back flow devices to keep the cold from running in through the ducts at night.
In case your wondering its 19' long, 45" high.
" /> I was lucky enough to have a guy offer me a few sheets of tempered glass so I sized the collectors accordingly. The glass is 45"x76"x 3/16" thick. I made the frames from 20ga metal stud track. The back of the collector is lined with 1/2" foil faced foam board that is rated for heat. Inside the hollow of the track I ripped some 3/4" pine and then more of the 1/2" foam board. This combination filled the hollow perfectly.
The corners were made by leaving the end caps an extra 2" long then folding them around the corner and pop riveting in place.
Screen frames I made out of furring strips with some corner braces. Screen is regular fiberglass window screen stretched very very tight.
I mounted this unit on the south wall of my shop and ducted directly into the building.
Venting right into the building presented a problem. My whole south wall is cabinets. But as luck would have it I was able to modify the end cabinet for the blower assembly. I'm using the fan from my old furnace. It is a 4 speed fan so I hooked it up to run on low. It is a little oversized but not terribly. This thing needs a lot of air.
End result.
Just got it together the other day but so far I'm pleased. We had decent sunshine here this afternoon and it was blowing a steady 85 to 90 degree air all afternoon. I still have to order out a temperature controller for running the fan but for now I'm running it manually. This won't replace a furnace but it will sure cut down on the gas bill though. I expect to have about $250 invested in this by the time I'm done. If I didnt get the glass I was going to use a product called Twin Wall Glazing, Menards carries it for about $50 for a 4x8 sheet. Still wouldn't have been an extremely expensive project.
Lot of work left to due such as residing around it and flashing and adding a controller and adding back flow devices to keep the cold from running in through the ducts at night.
In case your wondering its 19' long, 45" high.
If the women don't find you handsome, they should at least find you handy.
A thermal mass tank of sorts would add a lot and something to consider down the road.
