Solar space heater
#11
  Re: (...)
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.
If the women don't find you handsome, they should at least find you handy.
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#12
  Re: Solar space heater by mranum (Thought I would post...)
Cool! Or...hot...or something...



I keep threatening to do something like that with my garage shop...the garage doors are on the south side, so a 7x9 garage door is driving my sizing thoughts.
Dave Arbuckle was kind enough to create a Sketchup model of my WorkMate benchtop: http://www.arbolloco.com/sketchup/MauleS...nchtop.skp
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#13
  Re: Re: Solar space heater by MauleSkinner (Cool! Or...hot...or ...)
MauleSkinner said:


Cool! Or...hot...or something...



I keep threatening to do something like that with my garage shop...the garage doors are on the south side, so a 7x9 garage door is driving my sizing thoughts.




I happen to read an article not long ago that would be right up your alley. You might find this interesting.


Solar Heat and Light for Your Workshop or Studio
If the women don't find you handsome, they should at least find you handy.
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#14
  Re: Solar space heater by mranum (Thought I would post...)
Cool. You need to create a big thermal mass somewhere in or attached to your shop that you can duct the excess heat through during the day, rather than turn the fan off when it gets too hot. Unless you turn your shop temp. way down at night you will use a lot more fuel to heat it after the sun goes down than during the day when the sun is shining. That's the problem with solar collectors. They don't work when you need them most. I'm not poo-pooing what you've done, it's great, just suggesting that you can make it more effective. Creating a large thermal mass would allow you to store that excess heat during the day and recover it at night.

John
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#15
  Re: Re: Solar space heater by jteneyck (Cool. You need to c...)
I rarely ran my furnace when I wasn't in the shop which meant most of the time it was shut off by 7pm and sometimes wouldn't be run for days. Typically by morning the shop would be down to around 45. Furnace would run fairly steady for about an hour to get it back to about 65. Now I still need morning help from propane heat for temperature recovery and on cloudy days. However, if the sun wants to heat my work space for me I'm all for it. With this when it gets too warm in the shop a window will be opened or I will have to cover the collector to turn it off. Just shutting the fan off won't do as it would just overheat the collector. Too much heat during the day is a nice problem to have in this climate this time of year.

This was not, nor intended to be a sole source of heat. Just a very cheap suppliment.

A thermal mass tank of sorts would add a lot and something to consider down the road.
If the women don't find you handsome, they should at least find you handy.
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#16
  Re: Solar space heater by mranum (Thought I would post...)
Nice job. We had a warm air auxiliary system put on our previous house 25-30 years ago. It's thermostat was set to come on, when it had heat, before the furnace, and shut off when cozy warm. When ever the sun was shining the furnace did not run, the solar did it all, even in below zero temps. When a cloud went over the solar shut down.

My boss is a Jewish carpenter. Our DADDY owns the business.
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#17
  Re: Re: Solar space heater by mranum ([blockquote]MauleSki...)
mranum said:


[blockquote]MauleSkinner said:


Cool! Or...hot...or something...



I keep threatening to do something like that with my garage shop...the garage doors are on the south side, so a 7x9 garage door is driving my sizing thoughts.




I happen to read an article not long ago that would be right up your alley. You might find this interesting.


Solar Heat and Light for Your Workshop or Studio


[/blockquote]

Thanks...I've considered that as well. I just have to decide whether I limit the heating time to when I'm in the garage or not.
Dave Arbuckle was kind enough to create a Sketchup model of my WorkMate benchtop: http://www.arbolloco.com/sketchup/MauleS...nchtop.skp
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#18
  Re: Solar space heater by mranum (Thought I would post...)
I've seen these and they are brilliant.
I wonder what happens when you try and store some additional heat by adding small containers filled with a liquid like antifreeze, then as the sun sets, you'll have some stored heat to allow it to run a little longer?

I would certainly fire proof the blower section/cabinet- at least with drywall. Shorted motors/wires can cause a fire.
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#19
  Re: Re: Solar space heater by daddo ( I've seen these and...)
daddo said:


I would certainly fire proof the blower section/cabinet- at least with drywall. Shorted motors/wires can cause a fire.




That is a good idea and what I had in mind by putting the fan where I did. The box where the fan sits is all metal including a ceiling in it. The only thing that isn't is where it passes through the wall, the piece of ply for the hookup to the vent and of course filter door. Have to give that some thought. I do have redundant circuit protectors. The breaker that supplies the power then an additional fused switch to power the fan.
If the women don't find you handsome, they should at least find you handy.
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#20
  Re: Re: Solar space heater by mranum ([blockquote]daddo sa...)
I like it a lot, but I do have a question.

Why did you choose to remove the siding instead of building some kind of stand-off from the wall? I'd think you would have less issues with weather that way.
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