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Foil Solar Panels for Windows (VERY Easy) Build one an hour!by OhMike on December 26, 2010

Table of Contents

Foil Solar Panels for Windows (VERY Easy) Build one an hour! . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1

Intro:   Foil Solar Panels for Windows (VERY Easy) Build one an hour! . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2

Step 1:   Talking Materials and Tools . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3

Step 2:   Building the frames . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5

Step 3:   The back of the panel . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7

Step 4:   Prepairing the "solar" foil . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11

Step 5:   Apply Flashing to First Frame . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13

Step 6:   Applying the foil, the second frame and prepair for film . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17

Step 7:   Applying the window film and aluminum trim tape . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20

Step 8:   Final Step - Apply hangers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 26

Related Instructables . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29

Comments . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29

http://www.instructables.com/id/Foil-Solar-Panels-for-Windows-VERY-Easy/

Author:OhMike    The Savvy TechA technician for over 30 years.

Intro:  Foil Solar Panels for Windows (VERY Easy) Build one an hour!

Ohio Mike introduces this project by video. 

 

If you do Twitter... Please follow me there too http://twitter.com/iTechTV

I was watching my first video again originally describing the project and discovered this...

The day I made this video the highs were in the teens. I would hope you would agree that in the most well insulated house the furnace would come on at least a coupletimes even on a sunny day because the house does not have sunlight heating items in side a North room.

If you would... look at the video at the 5:50 second mark of the first video and pause it. You should notice the thermostat set at 65 degrees, which is where we keep ourhouse to keep heating bills down.

Now... even though the thermostat is set at 65 it shows the temperature at 70 plus degrees. .. the thermostat is in a North room in my house... The reason for theincrease is I have the fan turned "on" to allow air circulation throughout the whole house from the room being heated with the panels... can the naysayers explain thataway?

_______________________________________________________________________

This panel is only 3/4 of an inch thick and weighs in at less than three pounds. On a partly cloudy day the black foil collector reached about 150 degrees (during thesunny times). The film front only felt warm to the touch and the aluminum flashing on the back of the panel only made it to 98 degrees.

This type of solar panel (like most) only work if you have south facing windows; and of course, a little sun helps. But the nice thing about these panels... They are VERYeasy to make and hang "INSIDE" your window where you don't need to concern yourself with zoning codes or big ugly boxes hanging on the side on your house. Aplus, you can take them down in the summer; also, because of their design... you can use these in apartments and condos.

The design... there are virtually no size limits, allows you to custom size them to fit "ANY" window and they allow for light to come through around the edges.

The panel is without any electrical or mechanical parts and they work fine with its natural rising of heat through the back chamber of the panel. To aid the distribution ofthe heat rising to the ceiling in your room is to add a (SMALL) fan pointing to the ceiling to circulate the air or better yet, if you have one, you can place the fan onsomething like a bookcase with the fan facing down.

Another option for better circulation (throughout the home) add fans to pull the heat from the main room to other rooms in each doorway and set the fans to their absolutelowest settings.

Yet another option... turn your thermostat's fan to on so the furnace fan runs all the time; this will allow for the best circulation throughout the house... put it back to autoat night.

The only hard to find part of this panel is the Cinefoil which can be bought from my website http://imehrle.comLet's get started... 

http://www.instructables.com/id/Foil-Solar-Panels-for-Windows-VERY-Easy/

Step 1: Talking Materials and Tools

Materials needed for the Window Solar Panel:

1. Screen frame Material2. Screen framing Corners3. Aluminum flashing4. Black Cinefoil5. Heat resistant aluminum tape6. Window treatment film (comes with double sided tape)7. Suction cups8. Eye screws9. #10 eye screws10. Optional two soffit vents (not shown)

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Basic tools needed:

1. Tin snips or heavy duty scissors2. Needle nose pliers3. Measuring tape4. & THATS IT!!!4. Marking pen5. Utility Knife

-- Optional Upgrades--For easier and more accurate cutting and to upgrade your panel,these additional tools and parts are needed:

1. Hack saw for better cuts or even better, a power miter saw2. Small drill with 1/8 inch bit3. Riveting tool with 1/8 inch rivets 1/4 inch long4. Eye blot driving tip5. Needle nose pliers6. Straight edge (for cutting)

And of course, a hair dryer... if you are one of those super-observant people... you will see, I don't needthe hair dryer :-)

...

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Step 2: Building the frames

So that your cuts make for a square solar panel... tape together four lengths of screen frame. 

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After cutting to size, insert the corners. 

Completed Frames. 

...

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Step 3: The back of the panel

Use your hair dryer to heat-up the glue holding the sticker on. (makes removal easy of any stickers) 

http://www.instructables.com/id/Foil-Solar-Panels-for-Windows-VERY-Easy/

Measure the roll of roof flashing to your desired length. 

After marking, position a straight edge and tape it down.(Yep, a utility knife will cut flashing with a few passes) 

Carefully cut the flashing. 

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Mark to ends of your cut flashing for the vents you desire to use. 

More marking. 

Use a deep throat paper punch to get enough reach.I remove the piece catcher to see though the hole to help align the punch over the hole.

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Repeat. 

Finished...

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Step 4: Prepairing the "solar" foil

Remove foil from protective box. 

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Use the aluminum flashing you already cut to size for sizing the foil. 

Use utility knife to cut foil. 

Also cut to lenght. 

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Now roll the foil up for later use. 

...

Step 5: Apply Flashing to First Frame

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Align the flashing to the frame. 

Start the taping process for the flashing.

Tape each corner as shown. 

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Apply tape to the centers of each end and side. 

Position flutes to make sure a clear channel is maintained through the heating chamber.Although this is not a necessary step it helps and prevents waste.Flutes are just the cut off pieces (left over's) from the pieces cut to size. 

Tape the flutes down.

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Drill two to three holes in each piece. 

Turn panel over and start riveting. 

After all rivets have been inserted, turn panel over again to prepare for the foil.

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Step 6: Applying the foil, the second frame and prepair for film

Align the foil to the opposite side of the first panel with the flashing back.

 

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Center the foil and tape the center of one end.

 

Then center the other end and start tapping the rest of the panel.

 

Tape the corners first.

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Then tape the sides.

 

Place the second frame on top of the foil side and repeat the aluminum taping process.

 

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Start taping the perimeter of the second frame with the supplied double stick tape fromthe window film kit.

 

After all pieces of the frame are taped, peel back the protective layers of tape about aninch or so then set the panel aside.

...

Step 7: Applying the window film and aluminum trim tape

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Tape the film down on a floor or table to have it laying flat.

 

Tape, pulling each corner until you get the rolls out of the film...the wrinkles will be taken care of with the hair dryer.

 

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Now place the panel down with the double stick tape facing up and remove the tapesbacking paper.

 

Flip the panel over... As you can see, this process makes it easy to place the film on thetape with "NO" headaches.

 

Press down on all corners and around the perimeter to make sure the tape grabs the film.

 

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Cut around the perimeter to remove excess film.

 

Remove the excess film and flip the panel over.

 

Pre-measure and cut the aluminum tape for all sides.

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Peel back the tape backing a couple inches.

 

Align the tape and press the exposed sticky side of tape to the film.

 

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Align the non-exposed side of the tape and start peeling off the backing.

 

Now press the tape down gently to give you a nice clean edge.

 

As you apply the aluminum tape, flip the panel up to wrap the tape around the backfinishing off this process

 

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 Now for some fun (at least I think so).Use your hair dryer to shrink the film finishing off the panel.

...

Step 8: Final Step - Apply hangers

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Drill each corner with a 3/32 bit for starter holes.

 

Start the eye hooks by hand.

 

Carefully run the eye hooks down with a special driver bit. If you use any other tool

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be careful to not scratch the film.

 

As you can see, the eye hooks accept the window suction cups well.

 

 

Success... The finished panel !!!

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using SolarCells, To makeGlass frame DIYSolar Panel byEARTHFORSOLAR

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Comments

50 comments Add Comment view all 270 comments

 OhMike says:  Jan 13, 2011. 3:37 AM  REPLYNo disrespect to the very smart people out there, but in here lays the problem...

This project is not intended to be scientific or an engineering feat. It is a simple project that works.

And is for the not so mechanically inclined, it allows the average person to be able to experiment in this technology at a low cost.

 OhMike says:  Feb 19, 2011. 12:13 PM  REPLYThose small solar panels I made work... got my gas bill today. Last months payment (during a warmer cycle - December) was $131... this month (during acolder cycle - January) was only $126. http://bit.ly/Lower_with_Solar

Last year usage was 5.5ccf this year is 4.1ccf

~

 Video-lash says:  Mar 11, 2011. 9:36 PM  REPLYCinefoil can be found online at places like B&H photo or studio depot. I use it for video work all the time.

 OhMike says:  Mar 12, 2011. 5:37 AM  REPLYYes... but it can be found on my website toohttp://blog.imehrle.com/2011/02/10/solar-heating-made-easy----very-easy.aspx

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 titusm says:  Jan 16, 2011. 11:33 AM  REPLYhyNice and simple idea:)

I have a quick tip for you thou.

i noticed the aluminum frame you are using is usually used for mosquito screens (not sure exactly how it is called - it stops the bugs from coming in thehouse when the window is opened).

You have a rubber band that keeps that net stuck to the frame. It also stretches the net. I am so sorry that I don't know how to explain this to you but in mycountry usually this is used at the windows companies. (I mounted some myself). I’ll attach a picture.

You could use this idea to make this panel. It would work much much faster. And also you could use the mounting to the window idea- not the one in thepicture. If you are interested I can look for a picture and send it to you.

What you need extra is a small simple tool to put the rubber string or band inside. It has a rolling wheel that is as wide as the diameter of the rubber string.You press the string with it in place.

good luck

 llord willette says:  Feb 22, 2011. 1:56 PM  REPLYThe "rubber string" is called splining.

 sparky9 says:  Feb 6, 2011. 8:49 AM  REPLYThe rubber string/band is called "spline"cheers,Sp9

 pdionne says:  Feb 3, 2011. 1:48 PM  REPLYI would suggest adding additional flutes and run them from side to side, leaving a space on alternating sides, i.e. the first flute would be mounted rightagainst the left side of the frame and would have a gap of a couple of inches between the end of the flute and the right side of the frame. The next flutewould butt up against the right side of the frame and would have the gap on the left side. The next would be mounted like the first flute.

Doing this would cause the air to be retained in the panel longer and would increase the output temp of the air.

I would also find a way to increase the depth of the panel to allow more airflow, but remember, the flutes would also need to be thicker to restrict the air.

The idea of using screen frame is excellent and much easier than constructing it out of wood, as I was planning. Also, the idea of using shrink film is greatcompared to using plexi-glass, and lots cheaper.

Great project!

 roz392 says:  Feb 2, 2011. 2:34 AM  REPLYJust read "all" the comments. Yes - holes at the bottom too .My metal panel experiment had metallized material pegged onto the back for insulation anddirect the heat to the black front of the panel and not loose heat out the back.Seemed to be important to increase the heat.

 Physika says:  Jan 27, 2011. 9:58 AM  REPLYHi Savvy -- for some reason I could not post a reply to your last response (Jan 28, 7:28 AM), so I am posting as a new thread.

First, it is nice to see you again posting on your great instructable. I don’t want to be critical of your instructable, because you did a first rate job of putting ittogether and I do think it has value. You have generated all of this wonderful interest and been very generous responding to comments. But I do want todiscuss this fuel bill point. It is important.

First, there is no question that darker materials will convert more light to heat. And there is no question that your panel heats up…a lot. No need to prove thatto anyone. I would like to discuss the furnace observation you made.

Without being at your house to observe exactly the conditions of your furnace experiment, I can’t tell you with certainty what did happen in your experiment,but I can tell you with certainty what did NOT happen. What did not happen is that you did not convert appreciably more of the sunlight into heat than youwould by fully opening the shades. You just produced most all of it at the panel instead of in the rest of the room. This can be a useful thing to do.

I will offer one possible explanation (there are others) of your observation on the furnace not coming on. If you let the sunlight be absorbed by thefurniture/walls/floor, it will be stored and released slowly. So the furnace may still need to come on during the day, but not quite as much later in the daywhen the sun has gone down, as that heat is slowly released. Net fuel bills would be the same, unless somehow the released heat later in the day is heatingthe room up higher than you want it to be heated. In winter, this should not be a problem.

Another possibility...I assume you have already tried opening all the shades and observed the furnace coming on. Perhaps the shades are still blocking partof the windows.....just throwing ideas out.

You would really need to look at fuel bills for an extended period of time, and compare them to those incurred when you just open the shades, under verysimilar sunlight and weather conditions. Analyzing the daytime alone will not suffice. This is obviously a difficult experiment to create.

http://www.instructables.com/id/Foil-Solar-Panels-for-Windows-VERY-Easy/

I can see that you are skeptical of the theoretical arguments, and that is fair enough, as you have no way of knowing whether those of us making thesearguments really know what we are talking about.

Please don’t interpret these remarks as an all-out criticism of your instructable, because I do see plenty of value in it for producing the heat here rather thanover there, and releasing it now rather than later; for making the room feel warmer when you might be using it more….and the security, and all that. It is agreat instructable, very worthwhile for a lot of people. But you are not converting more sunlight to heat than if you open the shades. You are just putting itwhere you want it at the right time….which does have value!

 roz392 says:  Feb 2, 2011. 2:21 AM  REPLYGood points. If you use a solar curtain after collecting the heat in the room and contain it would that not be net over all more heat, basically because thetimeline is more efficient .I have been doing rough experiments using $1 ex office metal panels ( from shelves I think) , painted black and put up against asunlit window .They come half way up the window right across.The heat cranks when the sun hits a certain angle. After this inrush of extra heat which Ican feel at the top of the panels I close all the curtains. It stays warm all night.

 a.j.p. says:  Jan 27, 2011. 5:48 PM  REPLYI'm sorry, but I have to reply again...First - As I said before, more light IS converted to heat. The absorption efficiencies of black foil versus tan carpet are far from equal. It isn't just a matterof "here rather than there" or "now rather than later", although that is a part of living comfortably.

Second - There are a lot of people who turn the thermostat down or even off at night while they're alseep in their cozy beds(epsecially if they live in old,drafty houses). Even with your flawed assumptions, people in this camp WILL save money by using the panel. And for this scenario, "here rather thanthere" and "now rather than later" is very important and does save money.

 Physika says:  Jan 27, 2011. 6:30 PM  REPLYa.j.p. - I enjoy the discussion. I'll try not to fall into the same temptation of being insulting. I will just respond to the technical arguments.

First point of yours: "... then you are assuming the walls, furniture, etc absorb the light energy AS WELL as the black foil panel ..." - No, I am notmaking that assumption. That would clearly be an incorrect assumption. As others have already spelled out in this discussion, the light bouncesaround multiple times, losing some of its energy as heat with each reflection. In the end it all gets converted to heat, except for the small amount thatescapes back out the window. One must account for where the energy goes....little of it remains as light after a few reflections. Everything that doesnot escape the window as light is converted to heat.

Next point: "...this panel keeps it in the air rather than in the floors and furniture. So, the thermostat would trip less often and heating bills would belowered - but at the expense of a cold couch..." This is a very critical point to understand correctly. Heat going into the couches is not lost....it isslowly released back into the room. One does not feel it as much, so the perception of warmth is lacking relative to the panel. Net fuel bills aredetermined soley by how much heat flows out of the house, not by where in the house it is distributed.

Last point: "...There are a lot of people who turn the thermostat down or even off at night while they're alseep in their cozy beds ...." I accounted forthis in my comment, though didn't elaborate. Even with the thermostat turned down, the room is still heated from the furnace. The only reason thefurnace is not on more is because stored heat energy is being released from the walls/furniture,etc... back into the air to keep it warm. The energystored there from the sun would replace the energy put there by the furnace...lowering the fuel bills in the case of an open shade.

Good discussion. I am happy to keep it up, and will try to keep it respectful. I can see that you have some knowledge or intuition in this area, but I willtry to convince you that it is not complete.

I also reiterate my praise for Savvy and his good instructable. There is a lot of value in this project, but it is not in lowered fuel bills.

 a.j.p. says:  Jan 27, 2011. 9:08 PM  REPLYAlthough I don't see any end in sight, I can't help myself. Light does escape out the window in either the open curtain case, or the black panel.What isn't up for debate is that less light escapes while the black panel is used. So, without getting bogged down on just how much energy isabsorbed in either case, the panel clearly absorbs more.

I very well understand the concept of stored energy. I also understand the "critical" point that heat isn't lost in the couch. However, as far as thehomeowner is concerned, it is lost. The heat it slowly radiates at night is useless for someone sleeping in bed. They want it cold. Cold is cheap.So, that stored heat is really just stolen heat from the waking part of the day when the furnace is turned on, and as a result, the furnace must stayon longer. Net fuel bills are determined by the perceived warmth of the air. If the inhabitant feels cold, they will crank the thermostat.

I appreciate your openly proud restraint, and I am now trying to cope with the realization that my knowledge in this area is incomplete.

I'm sure this post has in no way changed your mind. And finally, I don't care if it does. This sort of posting is arrogant and irritating to otherreaders and I'm sad to have been a part of it.

 Physika says:  Jan 28, 2011. 3:33 AM  REPLYThere may be no end in sight....true enough. But I think we are not just going in circles, and are actually delving into technical detail withrational arguments. I was trying not to offend with my comments, but obviously failed, so I will try harder to stick to the technicals.

We are now into enough technical depth that it becomes very difficult to carry on a discussion in a forum like this. So I'll just toss out one thingthat I think is interesting to consider. Your statement that the panel certainly absorbs more light than the room would without it is actually upfor debate (sorry...not just trying to be argumentative).

Here is why: ;even dark objects are not perfect absorbers. They are doing very well if they absorb 95% of the energy and reflect 5%. Thispanel is right in front of the window, so much of the reflected energy goes right out the This panel might even be significantly worse thanthat...dunno.

Now I have to get into how much light escapes from an open shade as light repeatedly bounces around the room. Somewhat complicated, butif you imagine that everything else absorbs just a tiny fraction of energy off each reflection (which is not true....they absorb probably more than15-20%, but I don't have hard numbers), then how much light escapes? Without proof here (this is why the forum isn't ideal for thisdiscussion), I will claim that it is the ratio of the area of the windows to the total surface area of the walls/ceiling/floor). Now when we put backin the 15-20% guess on absorption of other objects from each reflection, we would actually find that a very small percentage of light actually

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makes it back out the window. Details to back that up are not easy to spell out here. I could try to add a lot more meat to that line ofreasoning, but I think it is too long and off topic for this forum.

I appreciate that you make rational arguments. We may not be able to go much farther than we have, and there is no need to convinceeachother of anything here. The discussion is meant to be fun and stimulate thought....which I think it has.

And Savvy should win some sort of award for Most Intriguing Instructable.

 OhMike says:  Jan 29, 2011. 6:25 PM  REPLYHas anyone watched the second video? It "should" weaken the naysayer’s arguments

 Physika says:  Jan 29, 2011. 7:10 PM  REPLYBy the second video, are you referring to the one showing how different materials heat up differently?

If that is the one, that does not really address the 'naysayer' argument (not my preferred term for us...but oh well.....). I don't believeanybody is disputing the claim that dark objects heat up, or that your panel heats up. Everybody would agree with that part, andalways has, as far as I have noticed.

The 'naysayer' argument is that without the panel, you still get the pretty much the same heat generated in the house as you would byfully opening the shades, but the heat generation is spread around all over the place as the light bounces around with a little bit at atime converted to heat with each reflection. Your panel converts it to heat all in one place. The panel improves the comfort levelbecause the air is heated more directly, which is beneficial, but in the end the amount of heat you are generating with the panel or withopen shades is very similar.

Anyway, thanks, Savvy for sparking all this discussion....I don't want to cause animosity by expressing these thoughts. I think yourinstructable has lots of value and inspires home energy-related projects.

 OhMike says:  Jan 30, 2011. 5:28 AM  REPLYNo problem Physika... I never get angry if someone does not see my point or doesn't agree... it is not socially constructive...

But... :-)

Not everyone opens curtains or drapes (or in many cases... "can") enough to let that light you guys are so aggressivelypromoting... again :-)

 Physika says:  Jan 30, 2011. 6:04 AM  REPLY

"..Not everyone opens curtains or drapes (or in many cases... "can") enough to let that light you guys are so aggressivelypromoting..."

True enough! And if one were to buy into the view we are promoting, it might suggest building 'perimeter' panels that generatethe heat where the curtains would normally block with their usually-bright-colored surface, and let the light shine through in themiddle of the window....much harder to construct, I would imagine, but maybe you have some clever ideas in that departmenttoo.

I do recall that you have already suggested partial panels to let some light in. This might suggest how that partial panel couldbe most productively shaped.

 OhMike says:  Feb 5, 2011. 12:47 AM  REPLYPhysika...

I was watching my first video again originally describing the project and discovered this...

The day I made this video the highs were in the teens. I would hope you would agree that in the most well insulated housethe furnace would come on at least a couple times even on a sunny day because the house does not have sunlight heatingitems in side a North room.

If you would... look at the video at the 5:50 second mark and pause it. You should notice the thermostat set at 65 degrees,which is where we keep our house to keep heating bills down.

Now... even though the thermostat is set at 65 it shows the temperature at 70 plus degrees. .. the thermostat is in a Northroom in my house... The reason for the increase is I have the fan turned "on" to allow air circulation throughout the wholehouse from the room being heated with the panels... can you explain that away?

 Physika says:  Feb 5, 2011. 8:24 AM  REPLYHi Savvy,I take your word on the thermostat….but I don’t think that your observation needs to be explained away. Rememberthat I am not questioning that your panel heats the air more efficiently than other materials would. I am pointing out thatthat light energy would eventually turn into the same amount heat energy anyway after multiple reflections in thehouse, except for the fairly small portion that reflects back out the window.

Now distributing the energy in a more optimal way is a way to save on fuel bills, I would agree. Especially if the furnacehas to kick on to heat the back rooms, and then overheats the front room that has the sun. But this is a different effectfrom what one might first conclude your panel is doing….converting light into heat that otherwise would not becomeheat. That is really my point…though I shouldn’t really claim it as ‘mine.’ It is physics.

Without the panel, I would also expect that if the shades were fully opened and you circulated air, then one would findapproximately the same reduction in fuel bills as with the panels. But, as you have pointed out, it is not really practicalto fully open the shades.

http://www.instructables.com/id/Foil-Solar-Panels-for-Windows-VERY-Easy/

I do think your panels have a role to play in heating the air instead of the solid objects, making it more comfortable. Andusing them to distribute the heat as you describe is also valuable. So I do want to repeat that I am not saying there isno value to the panels. It is just not quite the dramatic effect we would all like it to be of creating substantially more heatin the house than wide open shades.

 OhMike says:  Feb 5, 2011. 1:46 AM  REPLYBy the way... the 70 degrees plus allows the furniture, carpet and other objects you are defending as being aseffeceint... but they actually reach higher tempaturers through the ambient heating coming from the air being heated bythe solar panels. That my friend is the oven effect.

 frollard says:  Feb 5, 2011. 2:21 PM  REPLYTo solve this one must consider the house a bomb calorimeter. Figure out the heat capacity of various things. Yourpanel indeed heats air - which can be comfortable - but sitting on a cold couch, a very good insulator, is not fun.

The only improvement in the design would be louvring the black surface such that any reflections from the surfacehit another part of the same surface, otherwise I say you both have a case. Fact remains that if you can see thepanel from outside with the sun shining on it, it's letting light back out of the house, and if you can see inside yourhouse without the panel there, you're still letting light out - the difference is probably moot.

I bet joule for joule your system isa) more comfortable for the immediate local warmer air, andb) less comfortable sitting on the insulated cold couches which heat much slowerc) almost identical fuel bills if you set your thermostat the same in both scenariosd) needs more lights on in the house, since your sun side rooms are all dark. Lighting has gotten more efficient, buthaving to create light while the sun is out is a little bonkers

Solutions: a heliostat in the yard that aims ADDITIONAL sunlight into open windows, tracking the sun and adding afew extra meters of window space to the existing windows.

 roz392 says:  Feb 2, 2011. 2:12 AM  REPLYI'm about ready to make one. Having difficulty finding cinefoil. Panel costs $100 here in NZ to make without cinefoil. Window film being marketed by oneindividual only. One question shouldn't it be open at the bottom end for the cold air to funnel up through?

 zimmett says:  Jan 13, 2011. 8:25 AM  REPLYI loved the idea but can you see outside with these panels, or are they too dark in color to use as an ordinary window, thanks Steve Zimmett

 OhMike says:  Jan 14, 2011. 4:16 PM  REPLYExplaination video for the project here:http://www.youtube.com/watch?v=M1flG4kt5yY

 cheesphht says:  Jan 27, 2011. 6:46 PM  REPLYIsn't the explanation due to the plain fact that you're converting the light (all of it) into heat at a concentrated point? Whereas the light coming into awindow only heats percentage wise because of the angles and reflections not to mention the fact that there is still light given off in the room?

 OhMike says:  Jan 13, 2011. 8:33 AM  REPLYYep!!!

 Questor says:  Jan 13, 2011. 9:36 AM  REPLYyup what !?!?!?!?can you see out ??

 OhMike says:  Jan 13, 2011. 11:21 AM  REPLYSorry... as you can see there are a lot of post to answer and I am about to stop... I can't keep up. Again Sorry!

These panels can be made to whatever size you want; so, cover all the window or part of it.

Again Sorry...

 a.j.p. says:  Jan 26, 2011. 10:21 PM  REPLYIt never ceases to amaze me just how many "experts" there are on this site. I imagine that those who dispute the "thermodynamic" validity either:

1) don't hold any relevant degree on the topicor2) should be ashamed

No laws are broken. Fact. This panel is just more efficient at turning light energy into heat. Unless the carpet, furniture, walls, and ceiling are painted matteblack, and happen to be made of a material that transfers heat as readily as thin foil does to air, there is nothing to argue.

Nice instructable.

http://www.instructables.com/id/Foil-Solar-Panels-for-Windows-VERY-Easy/

 Physika says:  Jan 27, 2011. 6:52 AM  REPLYNobody is saying thermodynamic laws are broken....just pointing out that fuel bills are not lowered relative to just opening the shades. Heating happensall at the panel instead of at the walls, furniture, etc, making one feel warmer. But fuel bills are not lowered.

You imagination would be wrong on both counts.

 a.j.p. says:  Jan 27, 2011. 5:00 PM  REPLYNo. My imagination is right on at least one count. And, for your matter of fact statement that fuel bills would not be lowered to be true, then you areassuming the walls, furniture, etc absorb the light energy AS WELL as the black foil panel. Yes, one would feel warmer because the panel isdesigned to transfer the heat to the air and a couch obviously isn't, but in addition to that, the panel does a better job at absorbing the light than thesame room with just an open window. We see the color on the walls, carpet, and funiture because they are REFLECTING at least some of the lightspectrum.

And, even if your backwards reasoning were right and a sunlit room absorbed just as much energy, this panel keeps it in the air rather than in thefloors and furniture. So, the thermostat would trip less often and heating bills would be lowered - but at the expense of a cold couch. Pick your poison.

@TheSavvyTechHow do you manage to hold on to your sanity...?Keep up the good work.

 OhMike says:  Jan 27, 2011. 7:28 AM  REPLYa.j.p. is SPOT on! a.j.p. is SPOT on!! a.j.p. is SPOT on!!!

During sunny cold days (and it has been in the teens here in central Ohio) my furnace has "NOT" kicked on during those times (I work from home, soI am home "ALL DAY LONG". So... If your furnace does not kick on because of the use of a solar panel... how are heating bills not lowered?

I see absolutely NO credibility in the naysayers! And the naysayers have not produced one ounce of evidence that this doesn't work, other than theirexhausting rhetoric.

I put up an additional video here showing how different materials put out different amounts of heat from the "EXACT" same amount of light in theEXACT same amount of space and in the EXACT same environment... SO... show me "YOUR" proof that it doesn't work... I didn't think so :-)

 badad says:  Jan 25, 2011. 5:40 AM  REPLYdoes this generate electricity? can we generate elecrticity with this if yes then how?

 qazwe says:  Jan 24, 2011. 4:07 PM  REPLYThis Amazing!!!

_____PCFormatblog.ru

 rll7548 says:  Jan 23, 2011. 4:32 PM  REPLYI have more of a question than a comment. I've noticed that most of the other solar panels of this type have more dead air space than this one does. Howdoes the volume of dead air affect the panel's ability to raise the temperature in the room?

 roz392 says:  Jan 23, 2011. 1:29 AM  REPLYWhat exactly is that window film. Most window films reduce heat don't they? Wouldn't you want as much heat through as you can get?

 vincent7520 says:  Jan 17, 2011. 10:10 AM  REPLYOh well ! …

Sorry folks but I find all those physic niceties somewhat unreal.It seems that science people forget the initial aim of the those "window solar heaters" : heating a house thru solar rays instead of a costly fuel heater (anyfuel).Without doubt the thing works : if you want to add some finesse from your physics courses do so. You may adapt the principle to your own house or enhanceit to our benefit. But the idea is here (has been since a long time too ! …).

So let's be practical : as the panels prevent sun light to come into the room two conditions are needed to have this system work. Either you spend yourworkday out and you benefit from having a house fully heated when you come home with no charge (as it is winter most probably you leave and come homewhen it is dark), or you can spend the day in other rooms in the house lit by the sun.Therefore I would install these "panels" in an unused 1st floor or basement (provided it has real floor to ceiling windows and facing south) and let the heatcome up through either an open door or any other suitable (with no loss of heat)outlet (maybe made for that purpose only).

In other words the system may not be so useful for someone who lives and works at home in a one floor house with only one room facing south (unless it isthe bathroom or a kitchen … but most probably it would be the living room or the study / studio…).

The whole south wall of my living room has 4 windows with a total surface of 130sq ft. (6m x 2m) and I really do not need a heater when the sun shines : talkabout the greenhouse effect ! When this happens I spend half the day with only a T. shirt on !…But then at 5 or 6 pm temperature drops rapidly and this is when I wish I could have a mean to keep all that energy (or heat, whatever you want to call it) Icould have done without and hour earlier. Of course I could have painted the facing wall in black or installed a few jerry cans or other containers full of waterand also painted black … But this is my living room and somehow I don't want to transform it as an other workshop : I already have one in my basement !…

Any other idea ? … 

http://www.instructables.com/id/Foil-Solar-Panels-for-Windows-VERY-Easy/

 Physika says:  Jan 17, 2011. 11:19 AM  REPLYVincent, nice summary of the two conditions for this project. But the physics 'niceties,' are in fact quite relevant to a decision to use such panels. It is notjust nit picking...it is worth understanding whether fuel bills are lowered or not relative to just opening the shades on a sunny day.

The point being made by us science geeks is that you don't reduce your fuel bills relative to just leaving the shades open...so you can enjoy the benefit ofthe light room and have the lowered heating by just opening the curtains.

What this panel does for you is to generate the heat locally instead of distributing it throughout the room, and to heat the air directly rather than having itstored in the floors/walls/furniture of the room to be released slowly and less perceptibly. It also provides the security benefits mentioned. So there arereasons to do it.

But what it doesn't do is to lower the fuel bills relative to just opening the shades. And that is an important point, because it can really affect someone'sdecision about whether they want to do such a project or not.

Now your suggestion of putting them in the basement, or unused room and letting the air up is different. In that case, you are bringing heat up that wouldotherwise leak out of the walls and floor of the unused room, and really be 'wasted.' So I think that is a fine place for this idea, and it would actuallyreduce fuel bills. But in the upstairs rooms, if you want the light of the sun and the heat, then we should all feel very happy to just open the shades andknow that we are enjoying both the light and the heat to nearly their full potential.

 Unit042 says:  Jan 22, 2011. 1:49 PM  REPLYAs I watched the video as to how the window thing works, I ran a mental simulation (or thought experiment, if you will) as to the thermodynamicsconcerning possible benefits of this window device, and I must say Physika's comment is very true; that this produces localized heat directly to theair, and it produces no net thermal benefit for heating the house compared to opening the shades.Now, if I were to do this, in order to have any real net thermal benefit, I would have to either concentrate gathered heat to a smaller number of rooms,or have many of these hanging on the outside wall, with the heated air being piped inside. (Instead of heating the outer wall, the sunlight is gatheredusing otherwise wasted real-estate, so to speak)Assume we went with option 2, using multiple units on the outside wall so that A: we get a net benefit of solar thermal energy, and B: we still get A,on top of the optional benefit of having the window let in natural sunlight to illuminate the room (and thus reduce lighting costs).Well, air isn't such a good medium of heat transfer, let's try water. It has a higher specific heat (aka heat capacity), and it is denser, meaning it canhold magnitudes more of warm stuff to transfer inside. Now, we need water pipes, a circulation pump, radiators, etc.Huh, following this line of thought, we have a slippery slope leading to a water-circulating solar thermal gathering plant in order to actually have netbenefit maximized. Interesting.

Note that I am not trying to bring insult or ridicule upon this instructible in any way; I am simply making the point that the claim to "Collect FREE heatfrom the sun!" among other hype, is an uncomfortable amount of fanfare for a piece of tinfoil and black paper that darkens the room so that you canheat your ceiling, and spend electrical energy pushing the heat back down.... where it would have already been if the shades were open anyway, allthe while producing no net profit.

Again, no offense intended; this is a great project that can be done at home, costs little and produces results, ie some hot air over here and not there.If this was proposed as a general purpose heat-gatherer, it would be a useful device to take out into the field, or to camping, or whatnot, but as it ispresented...? No thanks.

 vincent7520 says:  Jan 17, 2011. 7:30 PM  REPLYthank you for your comments Physika.I guess I was a bit overtaken by lack of understanding of anything that relates to maths, physics, chemistry and all … which in turn makes me inclinetowards practical project without much afterthoughts.So your comment is very useful, at least for my frame of mind : it reminds me that I may learn something practical from what I read or hear if I payenough attention to it.Nice comment you made on my remarks about putting the heaters on a basement when possible.Thank you again.

 merlehanna says:  Jan 21, 2011. 9:20 AM  REPLYThank you for a very inventive idea and I agree with all of the positive comments on here. I hope if you have any more ideas that cant help everyone with alimited budget and a few free minutes to make improvements to the way we use/waste energy, please do...Thanks again for sharing this project...

 snekooei says:  Jan 17, 2011. 2:28 AM  REPLYsorry this is a basic question:So what's the rational for building such a screen?if there is a good sunshine, everything that is inside the room is heated (say curtains, for example) and then the warm air goes up and the air in the room iscirculated. This is why a room is warmed in the sunshine.

 martyjr9 says:  Jan 16, 2011. 8:30 AM  REPLYi like this idea.my question ,is there a corresponding set of holes on the other end of the panel?maybe i missed it but how does the cold air enter thepanel?each picture does not show both ends of the aluminum. thanks

 OhMike says:  Jan 16, 2011. 1:00 PM  REPLYCorrect... same number of holes at the bottom....

 ribatejoluso says:  Jan 16, 2011. 12:56 PM  REPLYThis idea looks cool and I would like to to add to the posts of some:Just because you are good in math it does not mean that you have all the common sense in the world. Not calling disrespectful names to anyone, just sayingthat some good ol school thoughts are not learned with any degree.

http://www.instructables.com/id/Foil-Solar-Panels-for-Windows-VERY-Easy/

 blackslax says:  Jan 16, 2011. 10:35 AM  REPLYThis is great idea; and I plan on making a few of these. However, I do have one question: I see that you put holes at the top so that the hot aior can escape.Shouldn't there be a few holes at the bottom to allow incoming cold air???

 robertlelliston says:  Jan 16, 2011. 9:08 AM  REPLYBTW.. Savvytech, THANKYOU...sounds like this will work for "ME"! My neighbor could hardly care less

 robertlelliston says:  Jan 16, 2011. 9:04 AM  REPLYOh My God!!!, You guys are so, FREAKIN', smart.....YOUR MORONS. Go back, read what you've written, and apologize. Oh, and keep in mind......"THEPET ROCK" Who's laughing now???????

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