Active Solar Air Heater

[michaelrp88]

OK guys. Here is the scoop. I haven't made another panel for the house yet due to one feature I'm not so happy with. The inside of the glass gets dirty over time so I'd suggest a hinged panel thats easy to open yet remain water tight. I just haven't got around to doing it. This litle panel, while not orientated or configured for optimim air flow still helps heat the garage.

Mike - Go as big as you can is my best advice.

[Redshift21]

@michaelrp88 That is an indication that either the cans are leaking air into the case or the case isn't airtight to the outside, either way this will not be good, if you are filtering the air entering the cans then dirt would suggest air entering the case from the outside as air in the cans should be clean, I'm not surprised you weren't getting a lot of gain from your rig, you only have a small panel and a large uninsulated building, you need to insulate : )

[havoc2000]

My name is also Mike, and I also live here in Southern Maine. I'm thinking of building myself a unit like this, only larger and using downspout.I just want to add the free heat to my cellar during the day, and hopefully benefit a bit from it.I'm wondering if you have done anymore of this experimenting, and if so, how it went! Mike :)

[cggage]

Just curious - I have a place in Troy, Maine, and am looking for some supplemental heat. You mentioned you were going to build one for the house. How did that work out? Any comments on whether it worked and was worth it? Thanks!

[allgovsarecriminal]

use one can row to let the air to the other side and the rest of the rows to let it flow back. well maybe i didnt understand your problem but thats what comes into my mind.

[jamieclarke321]

when did youtube become absolutely shit!

[IdahoViewing]

As far as the duct work being on the same end you might try creating a "U" shaped flow that would separate the supply air from the return air. I know this would create more of a flow restriction but it would be interesting to see if it increased the efficiency.

[wafi0123]

i think if u put your air intake put from inside the grage and out let also that means hot air recycle and doubling and heat soaring quick and efficiently. if bring cold air from out side heat loss is high. inside air recycle inside is heat exchanger technic. thanx

[michaelrp88]

Hello Zein. Yes I'm circulating the air but my wood working hoby creates allot of dust. I don't want this dust to collect in the panel over time. The paper filter you see in the vid does restrict flow quite abit, thats why I added the fiber filter on the bottom.

As for snow...Not a problem. I've had it covered half way up after a storm. It all comes off with a few hours of sunshine.

With your new shed keep in mind the difference between magnetic and true north.

[zeineguy]

just wondering if you are just circulating the air why you decided to use air filters? it is almost a closed circuit.. intake from the same shed it is returning to. maybe that is slowing your heating down. I am designing my own garage for next year and looking to build the roof at a larger area facing south. also wondering if you kept this up for the winter, if the snow was a factor on the system. Am thinking it would melt faster, depending on the angle.

[NOBOX7]

so how warm is it in the shed, i mean what was the temp gain

[michaelrp88]

@NOBOX7 Please see the thread below. Thanks for checking this out.

[landslave]

where is the snap disc located? what would be the cfm volume to reach equilibrium in full sun?

[michaelrp88]

@landslave Please see the thread below. Thanks for checking this out.

[2skullscrushing]

i bet you'd get a better ventury style flow if you feed one end, and exited the other.

[michaelrp88]

@2skullscrushing Please see the thread below. Thanks for checking this out.

[tim4962]

I find it interesting that you made this video when there was snow on the ground. :) How hot was the air blowing during the video? This data would help in my future construction. I am looking to come up with a design that will keep heating during the night, at least part of the night only using natures sun light. Thanks for the video.

[MrLeonard55]

Put a temperature gauge up there to show us.

[yalay5]

muy bueno,felicitaciones y gracias por compartirlo.

[MrLeonard55]

Make a video of you building it so others can build one.

[janapcoelho]

Did you try to run a water pipe inside this painel to heat the water in the same space?

[michaelrp88]

@janapcoelho Jan - Yes I considered interleaving a series of copper pipes to heat water in the same panel. Perhaps someone with more knowlege than I can shed more light on this matter. My theory is that the panel will absorb a finite amount of BTUs so if half is going into heating the water pipe then its stealing it from what would potentially go toward heating the air ducts. This panel would probably do either well but not both mediums at the same time. However;

[magicyte]

@michaelrp88 Copper has a higher thermal conductivity than aluminum. that's the same plan I'm working on. Heating water. Solar coated copper pipe would get very hot. Boiling in the summer. Warm in the winter...which in turn causes the hot water tank in the house to work only half the time. Sounds like big savings to me. I've done tests with boiling water to prove this btw.

[michaelrp88]

@janapcoelho Jan - However; If the panel was sized large enough for both then perhaps good results can be realized. With these panels it seems bigger is better. Hope this helps.

[zeineguy]

@michaelrp88 or making 2 seperate systems one for air and one for water. Have not seen anyone doing this with copper pipes for water yet. mostly just for heating air.

[janapcoelho]

Did you already try to but the water pipe insite this painels to heat the wather in the same time and space?

[spaceshipearth999]

lately i've been staring at all the vast unused spaces on rooftops...solar furnaces for air and water are cheap to make and can provide allot of heat energy...soon every roof will have these.

[water4fuelh20]

Nice job, don't be afraid to take your design and make a small widow box and blow that heat were it counts, ( your home) If your unobstructed. This is just what i have done with outstanding results. I'm lucky to be able to pump the air right into our living room with a unobstructed south facing view. Nothing fancy but it works and works very well.

[Bigjohnnywad]

Nice set up...

[689362003]

i wonder if you could put copper pipe inside or between the cans and use it as a water preheater as well? or would the water take all teh heat away from the air ?

[MrWombatPPC]

Why not include inside the box a Solar powered fan to pump the air around for free

[michaelrp88]

Thats the plan for the next panel. I want this to cost $0 to operate.

[mchlan92]

try getting a small solar panel that puts out like 12v at 100w and hook up some fans to that. should work

[rikkiesix]

Nice design!!

Pity you don't have enough insulation there. that would help more then a bigger panel.if you already insulate the roof that would make a big difference. Heat escapes mostly trough the roof so. Good luck and keep up the good work.

Greetings from Belgium.

Erik

Ps: i'm gonna make one for my appartment.

It will be on the inside of the but not mounted against the window. it will be a closed of box with plexiglas mounted close to the window. Wish me luck. hehe

[michaelrp88]

Good luck! True about the insulation.This garage is in such bad shape that its about to fall over. I took the video when there was snow on the roof to hide how bad it is. I can't see putting any money into it other than to tear it down and rebuild. It didn't hurt one bit to cut a big hole in the roof for the duct work.

[rikkiesix]

Thx a lot michael. I would say good luck too you also with building a new garage then and don't forget the insulation. It pays off in the long run and your heater is gonna work great. About now i'm gonna go to the hardware store and get some wood for my heaterbox.

Greetings

Erik

[solarcookerguide]

What's a snap disk?

[willyD200]

I just did a project where I ended up with 4 regular sized sliders, and one 8 footer. these are older single pane glass. I'm in the process of gathering all the different styles/info. before I attempt my own passive solar heater. I pretty much have all the stuff from jobs I've done over the summer so the cost will be nil. A couple questions, What about metal tape for connecting the cans and is there a special size for the end compartments?

I too live in S. Maine...here's hoping for a mildone

[michaelrp88]

The manifold size was dictated by the 4" conduit and the length of the assembled cans. I was able to make them the same size and liked the way it looked. I connected the cans with high temp RTV. Ace Hardware in Windam had black in a calking tube that was less than $10. Its not painable so I was very careful to not get any on the outside of the cans. I recently learned that if the manifolds aren't air tight to the rest of the panel the glass will get dirty. Feel free to come take a look.

[wiboater4]

When you get it working better make an insulated bin full of medium sized stone and run the air thru the bin to heat up the stone. Then at night when there is no sun you can still draw heat from the heated stone.

[michaelrp88]

That would certainly be one way to increase thermal mass but my roof sees enough snow loading so I'd hate to put a pile of rocks up there too. Besides, the loss would be high. Might as well mount the panel near the ground and run your heat pipe in a loop in the earth under your house. You may notice the effect of the passive heating. See richallenmusic here on you tube. He increased effeciency by putting his cans inside steel gutters.

[billyposter]

Been thinking about doing this using flexible chimney flue pipe arranged in a serpentine pattern. I can get s/h off ebay.. its double lined- is that an issue?

[michaelrp88]

look at the video posted by lawnngardenguy. his seemed to work pretty well. I almost tried it myself but the can design gave more surface area for the sun to hit.

[ReR0LL]

Cool!!

[1alasdar1]

What was the temp of the air omming out of the vent?

[michaelrp88]

Alasdar,

Output temp varies. the snap disk won't allow the system to function unless the air inside the panel is above 90°F. I've had readings up to 155°F but I could get much higher if I measured it in the middle of the summer. There isn't much loss in the pipe once it gets going. Hope this helps.

[iamkaven]

hi Michael very good job but if i were you i would of mounted it vertically instead of horizontally cause the hot air rises and the cold air drops so you put the intake on the bottom and the output on the top ...but that is my opinoin any ways great job i hope to build on someday

[michaelrp88]

Thanks Kaven,

You are correct about the natural convection between hot vs cold air however, consideration to the input and output port locations on the dwelling must be given. This panel is an experiment. My fan overcomes the natural air flow.

[whughey42]

Hi,

Very well done and professionally made system! I'm going to begin working on a similar system soon, hopefully. Thanks for the info and ideas!

Bill

[ArashiNage]

very nice!

[pgm98387]

Well done! I'd like to build a setup like that, it would cut back alot on my firewood consumption. Very green! Thanks for sharing, it will save some de naros!

Thanks!

[viking1au]

Cold & wet in Melbourne Australia. At least we don't have snow in the suburban areas. Will watch with interest.

[viking1au]

Maine gets bloody cold. so I will follow your progress, especially as you are entering through roof, rather than walls. You may consider single payne clear acetate or polcarb, to get the heat in better.

[ithorburn]

My panel is almost finished. I built mine like yours with the inlet and outlet on the same side. Mine has 255 cans. I bought a Bathroom vent fan at RONA. Tested the fan and it does not push air through. Im thinking about adding an outlet fan to assist in air movement. Im thinking with a double pass heat exchanger there might be too much resistance. Do you have any thoughts? Thanks

[michaelrp88]

Hard to say whats going on without more details. Most people are using a fan with at least 100 cfm with good results in any configuration. I researched duct work to size my fan and found that the static pressure in the system will drastically reduce your air flow. Multiple bends and yes fins will add to this. My cans are open ended and I'm using a 100 cfm fan and I only get about 40 cfm out. I'd get a bigger fan and/or make sure there are no obstructions. It should breathe well.

[sedgomatic]

Nice job Michael. I noticed you used a storm door for this.  Did you leave the frame in tact or did you remove it? I've got two storm doors that I want to use for this but I've heard removing the frame can be a real pain. Thanks.

[michaelrp88]

Its made from 2 single panes of glass removed from storm windows. Each are 28" square x 1/8" thick. I made a custom frame.

[michaelrp88]

The snap disk is in series with the fan. I put mine in the hottest part of the panel, in my case its in the top of the manifold. Good luck and keep us posted.

[ithorburn]

Nice panel and good explanation. Was wonering where to put the snap switch. Does the snap switch run is series with your fan? Plan to build a large panel for my house. thanks

[321ozzy]

Amazing video, thank you for your clear explanations. I've just started building a solar furnace myself, which will consist of 132 cans.

Your idea of using a filter sounds effective, I was thinking about all the dust that the panel would collect being a problem when the air is running through.

How does it affect the air flow?

I will try to video some steps and upload my furnace when it is ready.

[michaelrp88]

Thanks Ozzy. The paper filter on the side did restrict flow about 20% so I added the fiber filter on the bottom of the box. With both filters I don't recognize any flow loss. The best advice I can give is don't skimp on the size of the panel. In cold weather the fan will cool it down quickly. Good luck and keep me posted.

[321ozzy]

Thank for the advice, the filters will definitely form part of my version as well.

The size of my panel will be 1.80 metres by 0.9 metres. Probably 11 by 11 cans ( 121 in total)

The winters here are not cold during the day, around 18-22 degrees Celcius (64.4-71.6F), however during the night it drops around 0 degrees Celcius (32F).

The houses stay cold the whole day, with the use of the solar furnace this has to change.

Keep you posted.

[shoestring405]

Great looking project ! Please keep us informed

[michaelrp88]

37° outside and 135°F coming out of the panel until it cooled off to 90° inside after about 10 minutes. 98° increase!!!!!!

[matrixm777]

Good work... I look forward to seeing your house unit.

[excalibur440]

Looks great, enjoy the very cheap heat as the fruits of your labor. You may have to set up some partitions around you main work area during the winter to reduce the cubit feet your trying to heat. Just a thought.. Thanks for posting your project.

[grizzlybeers]

Nice panel, I just built one using 48 cans for testing but need to drink another case of beer before finishing it. What are your outlet temperatures?

[michaelrp88]

With the outdoor temp @35°F the output temp will quickly rise to 110°F then after about 15 minutes it will shut off @ 90° for a few minutes and the cycle starts again. Keep in mind that my 4" ducts inside the garage are not insulated yet but I found the loss insignificant as I got the same readings at the roof manifold. BTW...I drilled out the tops and bottoms of all the cans with a 1 3/4" hole saw. No fins or baffels.

[michaelrp88]

Let me clarify....The intake air is also 35°F so I'm seeing a differential temp of 75°F. If I switch to manual mode and let the panel warm up longer I'd get a higher reading. I'll try that this weekend.