My first project, With a few pics

[willythompson]

First off, thanks all for the information I have gleaned from this and other sites. I am truly fascinated by the use of this idea. I started off collecting cans, and midstream decided to switch to a screen collector. My Friends and family are still piling cans at my feet so...Seemed easier for me with better results for my first try. I live in Racine Wi (around Milwaukee) and obviously its pretty cold in this area. I wanted to try and help out the heat in my workshop. Because of a giant pine tree in my yard I lose the sun around 2pm I may cut that tree down in the future. But for now, I will just live with it. I start making heat around 930 in the morning and it continues till just about 2 (January) I know this will change for the better as the days get longer

I wired in a Duct fan booster, with a snap switch, and also an auxiliary receptacle, that I use for now to power a light I can see from the house if I am not out there. Just to kinda see when it is turning on and off. For the last 3 weeks of use I have gotten pretty comfortable figuring out by feel when it will be on. I will probably disconnect the the light today or tomorrow

In my shops position the window that I have the light in faces east. I notice that I get some very nice sun there early in the morning. I am currently thinking about building 2 collectors that will mount inside the shop to those windows. I am planning on doing one with cans and one with screen to be able to compare efficiency. (can anyone tell me if a collector box mounted inside needs to have insulation? or can it just be plywood painted black)

[willythompson]

I have a vid that i shot the other day using a thermo gun to see the temp being generated, This is a 100 cfm fan hooked into a snap switch. I start making heat about 930-10 in the morning and stop when the sun goes behind the pine tree around 145 - 200

[Amy@altE]

NICE! I love solar heaters, I installed one on my previous house in MA. Worked beautifully. Have you gotten any temp reading of the heat output of the collector? On a good sunny day, I saw up to 98F from mine. But mine was not DIY, it was a Your Solar Home SolarsHeat, so I wouldn't expect that high from yours. Would love to know what you are getting.

We used to sell the Canadian CanSolair heater that was made from aluminum cans. That thing worked amazingly well also, so once you get enough cans, I would definitely build another.

Others on this forum have warned about using a wood frame, it needs to be protected well or it will rot eventually.

[Amy@altE]

Holy cow, just saw your video after I typed my reply. That is SO impressive! Well done!

[willythompson]

NICE!

Others on this forum have warned about using a wood frame, it needs to be protected well or it will rot eventually.

I built this out of treated lumber (1x8) and gave it a lot of paint. I was thinking about using steel studs, but I had the room for 8" depth so I went with 1x8. I rabbited the back and front to receive the ply and the front panel, then used a carpet molding to cover the edge and secure the "glass" so that I can take it apart and make mods as I see fit. so far I don't know if I need to adjust anything. I am a carpenter by trade, so if the box rots It will just make another lol nice attitude eh?

Steel rusts wood rots, so its a horse a piece in my mind and wood insulates better. well at least that is the mind set I used haha

[willythompson]

I had a 2' section of pipe coming thru the back wall, and decided to extend the out put to where I stand most of the time while working in the shop, it is now about 8' long with a down turn. Obviously its on the ceiling of the shop. The day I took that vid it was around 15 degrees outside, and the shops ceiling in the area of the output was 80 after about an hour as you can see.
outfeed into shop.jpg

this was the pipe with temp wiring before adding on, and securing the 110

[J.P.M.]

First off, thanks all for the information I have gleaned from this and other sites. I am truly fascinated by the use of this idea. I started off collecting cans, and midstream decided to switch to a screen collector. My Friends and family are still piling cans at my feet so...Seemed easier for me with better results for my first try. I live in Racine Wi (around Milwaukee) and obviously its pretty cold in this area. I wanted to try and help out the heat in my workshop. Because of a giant pine tree in my yard I lose the sun around 2pm I may cut that tree down in the future. But for now, I will just live with it. I start making heat around 930 in the morning and it continues till just about 2 (January) I know this will change for the better as the days get longer

I wired in a Duct fan booster, with a snap switch, and also an auxiliary receptacle, that I use for now to power a light I can see from the house if I am not out there. Just to kinda see when it is turning on and off. For the last 3 weeks of use I have gotten pretty comfortable figuring out by feel when it will be on. I will probably disconnect the the light today or tomorrow

In my shops position the window that I have the light in faces east. I notice that I get some very nice sun there early in the morning. I am currently thinking about building 2 collectors that will mount inside the shop to those windows. I am planning on doing one with cans and one with screen to be able to compare efficiency. (can anyone tell me if a collector box mounted inside needs to have insulation? or can it just be plywood painted black)

You will get slightly more solar energy into the space with a simple window than you will a simple window with a solar collector covering it.

Solar thermal collectors that cover a window may be educational and fun but they do not add heat to the conditioned space more than a simple, well sealed window by itself. Windows by themselves are a more efficient way.

For more solar energy to the space, the panels need to be outside the heated space and not blocking the window(s). A panel being used inside a conditioned space is doing nothing more than using energy already inside the space - no more. Do not confuse temp. with quantity of heat.

For safety reasons, I'd avoid using wood products as a solar collector material.

[J.P.M.]

NICE! I love solar heaters, I installed one on my previous house in MA. Worked beautifully. Have you gotten any temp reading of the heat output of the collector? On a good sunny day, I saw up to 98F from mine. But mine was not DIY, it was a Your Solar Home SolarsHeat, so I wouldn't expect that high from yours. Would love to know what you are getting.

We used to sell the Canadian CanSolair heater that was made from aluminum cans. That thing worked amazingly well also, so once you get enough cans, I would definitely build another.

Others on this forum have warned about using a wood frame, it needs to be protected well or it will rot eventually.

Forget about rot, if it's not protected, it may combust as the kindling temp. of any wood exposed to elevated temps. is lowered over time by all the hot air/elevated temps.

DIY air cooled solar thermal collectors can have temps. as high or higher than mfg. units, depending on design (or lack of it). Higher temps are usually at least a partial and usually major function of flowrate.

[willythompson]

That is interesting about kindling the wood. Almost every part of the wood inside that collector is covered perfectly with 2 sided foil foam. I hear what you are saying, am not arguing with you, but my logic tells me that the wood is being insulated from the heat, as well as the box is being insulated from the outside temps. There is no air movement across the wood directly, nor direct temp from the inside of the box. Everything has been painted with high temp bbq paint. not sure that helps or hinders? The only thing in the box that is not covered in foam is the stretcher I made for the screen.

Is there any confirmed instances of one of these diy (or other wise) having spontaneous combustion?

[J.P.M.]

That is interesting about kindling the wood. Almost every part of the wood inside that collector is covered perfectly with 2 sided foil foam. I hear what you are saying, am not arguing with you, but my logic tells me that the wood is being insulated from the heat, as well as the box is being insulated from the outside temps. There is no air movement across the wood directly, nor direct temp from the inside of the box. Everything has been painted with high temp bbq paint. not sure that helps or hinders? The only thing in the box that is not covered in foam is the stretcher I made for the screen.

Is there any confirmed instances of one of these diy (or other wise) having spontaneous combustion?

I had one in the mid 70's, but I was too busy with a hose at the time to take photos. I intentionally stagnated it in an attempt to determine the overall loss coefficient of the small test collector I built when I thought I knew something. Such things usually don't happen, but the large variation in design options makes it an ever present consideration even if a small probability. Better safe than sorry. Small probability - perhaps dire consequences. Take what you want/need/find useful from the tale. Scrap the rest.

On another matter: Am I under a misconception or are you planning to operate these collectors inside a building ?

[willythompson]

On another matter: Am I under a misconception or are you planning to operate these collectors inside a building ?

I have only built one. the pictures are at the top. it is outside piped into the garage. yes I was considering making some that mounted to the window frame inside. You got me spooked now, as well as wondering if the effort is worth it. Will have to think a bit on it.

[J.P.M.]

I have only built one. the pictures are at the top. it is outside piped into the garage. yes I was considering making some that mounted to the window frame inside. You got me spooked now, as well as wondering if the effort is worth it. Will have to think a bit on it.

I'd keep it outside - away from any windows. Putting it inside the dwelling in a window, or outside blocking a window only intercepts solar energy that would otherwise pass through the window and be absorbed by some other material inside the structure. The heating effect of the solar energy on the dwelling and its contents is the same whether some of the incoming solar radiation is absorbed by a solar device or a solar cat sleeping in the sun or anything else inside the structure. (kudos to Jim Augustyn on the solar cat).

Regards,

J.P.M.

[green]

It's funny, I debate this one (window collectors) all the time in my mind. I do experiments in the windows of my south facing 3 season porch. I make small scale solar heaters and test the output. I know the Sun is shining through the windows and heating the room, but I often wonder, because the room is painted white, how much warmer would it get if it were painted a darker color. I ponder this because as you touch or measure the temp of the white walls, they are much cooler than dark objects in the room. Where is that solar energy going? Is the white stuff reflecting it directly to the air, or is it going right back out the windows it came in through. Since my wife won't let me paint our beautiful bright shiny porch a dark drab color I guess I'll never know. lol

That being said, I do agree that collectors should be outside to bring in extra energy that would have just been absorbed by dirt or snow.

[J.P.M.]

It's funny, I debate this one (window collectors) all the time in my mind. I do experiments in the windows of my south facing 3 season porch. I make small scale solar heaters and test the output. I know the Sun is shining through the windows and heating the room, but I often wonder, because the room is painted white, how much warmer would it get if it were painted a darker color. I ponder this because as you touch or measure the temp of the white walls, they are much cooler than dark objects in the room. Where is that solar energy going? Is the white stuff reflecting it directly to the air, or is it going right back out the windows it came in through. Since my wife won't let me paint our beautiful bright shiny porch a dark drab color I guess I'll never know. lol

That being said, I do agree that collectors should be outside to bring in extra energy that would have just been absorbed by dirt or snow.

Debate all you want, but don't think you are providing more heat to a dwelling by putting solar collectors in an enclosed space or blocking a window.

There's a lot more to it than this but, VERY briefly:

Solar energy enters a space through openings (windows). It hits an object inside the space and is either absorbed or reflected or transmitted (if partially transparent as in glass). Usually two of those mechanisms - absorption and reflection are present for opaque materials. The sum of what's reflected, absorbed and (perhaps) transmitted by a surface or object must equal the radiation that is incident upon that surface. For a totally "white" interior, a lot of the incident solar radiation is reflected off the white surfaces. Some of that reflected energy is intercepted by other "white" surfaces and reflected again, and again. Some of that reflected radiation, maybe a lot of it depending on window size, room size, room shape, etc. eventually goes in the direction of the window(s) and leaves the enclosure. Most of the incoming energy is eventually either absorbed and stored by the interior, effectively raising the room temp., or leaves the enclosure via the window.

Something called an "energy balance" on the room - basically what goes in (solar energy) must equal (what goes out plus what stays in) - sorry - it's the law. If the room is all "white" solar energy bounces around more and is absorbed less by the surfaces. Eventually a lot more (but not all, and maybe not even most) of the solar energy leaves the same way it came in - via the window, than if the room is "less" white. That's a good portion of the reason (but far from all of it) why dark rooms with windows get hotter than white rooms with windows of the same size and location.

In reality, those white surfaces are not actually "white". They are what are referred to as "grey" - that is, they reflect a portion of the incident solar energy, maybe a lot of it, usually somewhat as a function of the wavelength of that radiation (most white paint actually absorbs a small to a fair amount of the infrared portion of the solar spectrum - hence, there is some absorption of the total solar spectrum and some heating - just not usually a lot). The human eye sees a "white" surface as reflecting most everything. In reality "white" surfaces reflect more of the visible wavelengths of electromagnetic radiation than say "black" or other dark colors. As you observe, white surfaces are cooler than black ones. Light brown are somewhere in between, dark green are almost as warm as black.

Locating collectors in the room will not get you much in the way of additional heat in any measureable way. Any benefit, such as it may be, will come from less energy leaving the room because the white reflecting surface area is smaller. You can have the same heating effect by using a piece of cardboard the same size as your collector painted black and placed in the same position as the collector, but you won't get more net energy into the dwelling with either scheme. A little less will leave with either scheme, but I'd bet you'd not be able to measure it, and for other reasons dealing with elevated or excess room temp., the enclosure heat loss will likely go up, negating a slightly lower reflection loss.

And, putting collectors over a window only blocks solar energy that would otherwise heat the dwelling with about the same or slightly higher efficiency and in about the same amount in a "passive solar" way.

Do not confuse energy quantity with temperature.

A few asides.

As you do your experiments in the white room, it will get warmer due to the darker colored objects in the room - the collector, you wearing your dark solar sweater and shades, the dog, etc.

Try this : Look around for a south facing window on a sunny day. Look at it from the outside at some distance, say 100 ft. or so. If the shades are open, I bet it looks black. Reason: the room/window combination is acting as something called a "cavity absorber", meaning most of the light entering through the window is being absorbed by the (probably mostly non white) interior surfaces and staying in there. Now do the same with your all white space and observe what you see. Less dark maybe ?

Air in the room is absorbing some of the heat, but close to zero in the bigger scheme of things.

A passive solar energy trick: In a space exposed to sunlight, it's often a good idea to make those surfaces exposed to direct sunlight a dark color and make those objects heavy - concrete pony walls, floor tile, heavy furniture, etc. Have shaded areas lighter in color for the walls, and have the non massive things like shades, rugs, occasional pieces, also light color. Light will reflect into dark areas and also eventually tend to hit and be absorbed by the dark and heavy objects, helping some with the overheating problem. Such schemes help with the glare and overheating problems often found in passive dwellings designed by people who are clueless about what they're doing.

Take what you want/need of the above, scrap the rest.

[Amy@altE]

It may be useful for you to read about Trombe Walls. http://sustainabilityworkshop.autode...ached-sunspace and http://en.wikipedia.org/wiki/Trombe_wall, They were big many years ago, but fell out of favor. Maybe your wife would let you disguise a trombe wall as a bar or something.