Bug screen solar hot air collector
 

Hey gang I thought I would do a build thread on my solar hot air project. It started out as a proof of concept for me (Gary Resa and others made it work long before me but I didn't believe it would work so well in Winnipeg) and now I'm hooked on solar power as it works quite well. I had been put off trying this by a friend who said he'd tried making his own and he hadn't realized much heat during the winter. I'm glad I didn't listen (I'm quietly stubborn) and went ahead anyway. Now I'll have to ask him about his system to find out what he did wrong.

It works even though I had to make some very late design changes to accommodate a concerned wife. I think now that she's seen the performance of this unit and the finish level possible that future projects won't be as influenced.

I learned that building a panel in place would be a much easier way of doing things, but that I would be committed to finish within a reasonable time. My panel spent two years in my garage before I got mad at it and hung it up already. I suppose you could call me a procrastinator too. A recovering procrastinator.

Vital stats: 4x8' collector so 32 square feet minus a few for insulation thickness. I used standard Fiberglass bug screen in two layers as an absorber and used 4" ducting run by a NuTone radon fan. Controlled by a common snap switch or a manual override for trouble shooting. I followed Scott Davis' plan of routing the ducts in the house.

I have decided that installing on the side of the house vertically is the ultimate home for this panel. It'll get rid of losses over the long ducting runs I've used and directly heat the living space instead of the basement. Sounds like a good summer project. Maybe a second panel?? I will also go with 6" ducting and fan. I'd like DC and variable speed.

Next up: Pictures!

I have been digging through the archives and have found that all of the pictures of the panel construction have been lost in a recent computer upgrade. I do have photos of the install however. Sorry about that!

I'll give more details on the panel itself after today's pic post.

http://ecorenovator.org/forum/member...into-place.jpg

Here's the panel just after being lifted into place. I did this myself and it wasn't that hard, just needed to prepare. I'm used to carrying sheet goods at work for a construction supply company, so technique helps. I'm not a big guy. The biggest help was the little 2x4 tabs that grip the front of the panel. The bottom ones were in place while the tops were only held with one screw so that they could be rotated up and out of the way until the panel was set in place. Then the tabs were rotated down and I could let go! Then I fastened the panel solidly with deck screws. Uprights are 4x4 pressure treated wood set in concrete. Many holes in bottom as I switched designs from downpipe collector to screen after construction began. I filled these holes with foam.

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Here is detail of assembling the ducting for the panel and a general view of the outdoor electrical. I ran power out to an outlet to plug in the car and power out to a light fixture at the same time so I only needed to drill one hole through the concrete. I rented the proper tool from Home Depot. I think it was a $50 hole. Ha! Snap switch cable simply unplugs from house in the summer. That receptacle is fused for my fan so nothing else can be plugged here.

What I learned: Too many elbows reduces flow. Strain relief for electrical is a good idea, though I fastened the wire securely to the panel in many places I don't like that the run into the panel is not strong.

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Here's detail inside the panel of the snap switch install and the return duct to the house. As I tipped the panel on it's side at the last minute, the hole that was on top of the panel was now on the side in the middle. So is the snap switch. Certainly not ideal. This summer I may rectify this. I also may mount it upright against the house and fix the problem that way! :D
Insulation is 1 1/2 inch foil faced I got for a song from work as it was dead stock that sat for 8 years. They were happy to take it off the inventory list. They only stock 3/4 inch and got stuck with a cancelled special order.:D

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Routing the ducting through the window grates. If I want to go to 6" ducting it can't go here.

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What is that nasty stuff in the elbow? Ew.

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High tech solution to thermosiphoning at night. ha ha. NuTone fan secured to wall.

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Completed installation except for thermosiphoning protection. I simply capped the ends at night for a week or two.

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Glazing fogged up from thermosiphoning at night.

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Cleared off from the sun.

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Butterfly flappy thing installed that came with fan keeps most cold air out at night, but not all.

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This little flap did the trick. Almost no detectable air flow now.

http://ecorenovator.org/forum/member...duct-open.jpeg

Wires are for temp sensors.

http://ecorenovator.org/forum/member...air-panel.jpeg

In 3rd year of operation and I still haven't insulated the last 4 feet of pickup air from the house into the panel. Need to scrounge some as I can't justify buying a whole package for $50, or just mount it on the wall and get rid of all losses due to ducting through cold air. Used vinyl siding destined for the dump to cover panel back, some nice 10" aluminum fascia for the sides, and a bit of roll roofing on top. The roofing is hokey and could be done better.

http://ecorenovator.org/forum/member...air-panel.jpeg

The front of the panel. It's near Winter solstice at about 4pm. Sun won't be up long. Wish I had bigger windows, but I suppose I have more room for panels! House is at 2pm or so, panel is at 12pm as close as I could make it. I don't think I'd lose too much mounting to the house compared to duct run through frigid air.

http://ecorenovator.org/forum/member...moved-fall.jpg

End of summer. I'm set up to remove the summer cover that's made of vinyl siding. Comes off in a few minutes in a one person operation. Secured top by sill trim and bottom by starter strip while the rest simply hook together and are held in place by j-trim.

http://ecorenovator.org/forum/member...ment-floor.jpg

Here's my monitoring station installed on the main floor. Cheap Bios units from Walmart for 9 bucks or so. I used network cable to lengthen the runs to the sensors. The bottom temperature is the remote temperature. They are left to right: Panel, output into house and intake from basement floor. It's -10C outside. I could get more performance by insulating the last 4' of ducting, or better yet mounting on the wall of the house and putting that warm air into the upstairs living area.

That's it for now folks!

Here's another picture of the panel in the Summer. It can disappear if you want it to:

http://ecorenovator.org/forum/member...ce-summer.jpeg

This summer I grew Scarlett runners on the panel. Very tasty and juicy and the flowers brought us humming birds this year. There might be nine vines or so here. I attached netting to the top of the panel for them to climb.

What temp snap switch did you use? I have a panel already made, its just waiting to be installed.
Good looking project!

I believe it was a 120 on 90 off switch. I would go to a lower temperature range next time as some very cold days there is usuable heat but the switch cycles off too early. Maybe a 80 110 switch.

Awesome thanks man! I thinking I'm going to go digital on this project.

Awesome Link!
The Zen of Passive Solar Heating Panel Design

Very nice read. Thank you!

Found em!
 

Hey Gang I found the pictures of my panel as I was building it, so in the next few days I'll post them as time becomes available.

I'll be waiting, I got my panel onto the roof friday by myself. Looking forward to seeing your build.