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Ohio Mike introduces this project by video.
If you do Twitter... Please follow me there too http://twitter.com/iSMTV
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 couple times 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 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 North room in my house... The reason for the increase 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 that away?
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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 the sunny 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 VERY easy 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. A plus, 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 of the 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 on something 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 absolute lowest 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 auto at night.
The only hard to find part of this panel is the Cinefoil which can be bought from my website http://imehrle.com
Let's get started...
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Signing UpStep 1Talking Materials and Tools
Materials needed for the Window Solar Panel:
1. Screen frame Material
2. Screen framing Corners
3. Aluminum flashing
4. Black Cinefoil
5. Heat resistant aluminum tape
6. Window treatment film (comes with double sided tape)
7. Suction cups
8. Eye screws
9. #10 eye screws
10. Optional two soffit vents (not shown)
Basic tools needed:
1. Tin snips or heavy duty scissors
2. Needle nose pliers
3. Measuring tape
4. & THATS IT!!!
4. Marking pen
5. 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 saw
2. Small drill with 1/8 inch bit
3. Riveting tool with 1/8 inch rivets 1/4 inch long
4. Eye blot driving tip
5. Needle nose pliers
6. 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 need the hair dryer :-)
...
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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.
Last year usage was 5.5ccf this year is 4.1ccf
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I'm thinking about buying this pack of black foam board from Amazon http://www.amazon.com/Bazic-Board-Inches-Black-594-25/dp/B00275EC64/
Then, I'd hang it using the same suction method you showed us, and putting a spacer between the foam board and the window. That's it.
By skipping the step of creating a frame and putting plastic sheeting over it, I believe that we simplify the construction process a lot. I posit that both of our approaches still have the same net heat conversion per unit area. My approach would not have as high of a temperature for the output air, but there should be great flux in air movement.
Anyway, I'd love to hear your thoughts and invite you to poke holes in my approach.
I like the low-cost, easily accomplishable concept here. I think some of the nay-sayers just need to listen as you explain that this is not meant to be some exotic and super high tech (hard to do) contraption. It is a simple project with a simple design, on purpose. I like how light and easy to move they are too, which is something to consider before anybody goes and builds some with water or soap-stones inside. You will want to wash your windows and dust the sills sooner or later. Simple, light, economical, practical, and usefull, these are the goals of this project, and you have hit the mark in every catagory. I think your design is superb, and thank you Sir, for sharing it with us. 5 stars & double thumbs up!
I am working on an outdoor collector.
The absorber is corrugated sheet. The frame is drywall profile UW 125
Glazing is a plastic plate Akrylon.
Insulation is Styrodur.
Area for heat transfer is about 2 square meters.
Anyway nice vids and the quantative reasearch was great... There have been a lot of solar/air based systems on the web, a lot of them are based on "black" causing the heat to fall out of the air. The use of black netting in a window will warm up a room on its own and allow you to see through it to the garden/view..
Might I suggest you build your box using a mesh with both sides see through,that way you can see through and force the convection process.
Just a thought
The whole idea is to allow the chamber behind the film to hold the heat the foil captures and then only allow a small amount to escape through the opening at the top.
Bottom line... any black captures better than any other color and materials make a difference too.
Thanks for the comment!
Metal is used because it conducts the heat far more ready than other materials. If you're looking to store heat to be released at a later time - like the person with the sand in the jars - you don't use metal.
And - btw sand in the jar person - water is the best heat capacitor on earth.
So, window screen, weed block, shade cloth or such could be used, but the thicker the material, the more time it would take to get to a critical temperature where it would conduct or radiate the heat off, causing a convective air flow than the metal would. Weight would be a negligible difference, depending on the material used - compaired to the foil used in TS's.
The argument - LOL I can't believe I'm getting into this. The solar energy entering the untreated window is pure light energy. Once it hits objects - flooring, furniture, appliances, it is either reflected as light energy, or converted into heat energy. When converted into heat energy, it is either absorbed by the objects, or radiated off.
So yes, there is some heating occuring, otherwise if you aired your house out on a single digit day (like today), it wouldn't come back to temperature quickly - due to all of those objects radiating their heat to equalize all - air and objects.
However, to say that light energy is being used to its utmost efficiency is a misnomer. It depends on the desired outcome. For light - yes, it's as efficient as it can get, barring curtains and drapes and blinds. But if you're looking for heat, the most efficient way to convert the light energy to heat energy is to use a flat black material. And then, if you want to use the heat immediately, you chose something that has little capacity to hold heat- like metal. If you want it to be used over time, or during a cooler time period, then you use something that has great capacity to hold heat - stone or water - called thermal mass.
Again, I hope I've helped, rather than creating more controversy! LOL
Let the discussion abound!
Of course, in the end, water is cheap and plentiful
You might like the following link:
http://www.buildinggreen.com/auth/article.cfm/1998/4/1/Thermal-Mass-and-R-value-Making-Sense-of-a-Confusing-Issue/
I feel like we're not speaking the same native tongue. LOL So please forgive me.
Soapstone isn't made like rock wool or fiberglass. It is quarried. I just did a search on soapstone, cultured soapstone and manufactured soapstone and came up empty. So I'm guessing you're speaking in very loose terms or know of a process I don't and can't find.
"Thermal Capacity of brick, not specifically firebrick, is about 85% of Soapstone. Secondly; Brick transfers heat slower than Soapstone, seemingly at 1/6 the speed."
Thermal Capacities:
Iron 0.450
Aluminum 0.890
Water 4.181
Concrete 0.880
Brick 0.840 Cp J/(gK)
Soapstone 0.98
Thermal Conductivity - k - (W/mK
Calcium Silicate insulating Board at 600F 0.097
Iron 60
Aluminum 250
Water 0.58
Concrete 0.42 to 1.7
Gold 310
Silver 429
Thermal Conductivity
Brick between 0.98 and 1.13 W/m.K
SStone6.4 W/mK
This information was found at; Traditionaloven.com "Firebricks – heavy dense fire clay bricks" and Tulikivi.com "The characteristics of soapstone"
And you're right - mass is the most important aspect to heat capacity. And I was merely making a point with water, not stating it should be used. Some people do, but as one site put it, it has no structure. LOL - not easily used.
Having said that, the best thing to use is what you have available and can afford. If you are truly looking at thermal mass for heat storage couple with passive solar, please consider building a tromble - basically a heating wall.
And like heating with wood, you want the heaviest material that takes up the smallest volume. Wood heats by mass - not volume. A wood that is lighter - like poplar, won't give as much heat as the same volume of a heavier wood like Hickory or locust.
So something like pumice won't work well for heat storage as soapstone, bluestone, brick, etc.
If you could send a link to the manufactured soapstone, I'd be interested. I found nothing last night.
On the other hand, water is much cheaper and more plentiful than soapstone. It can be piped to other areas for heat transfer.
I'll have to look more closely at the site you offered. My knowledge of the sciences is sorely lacking. It is my understanding that, for storage purposes, mass is important. As such, they may not have intended to include things like rock (including soapstone) when they talked about more common thermal storage materials. Any details you have would, obviously, be helpful.
And yes, soapstone is quarried (I've "quarried" a little here in Washington); however, it's also manufactured. As I mentioned, you can mix waterglass (sodium silicate) and talc[um powder] and bake it to manufacture soap stone. Nature does the same thing, just on a large scale.
As an side: Soapstone is superior to firebrick for fire places and stoves. It will take far more heat without breaking down. Here is one reference:
"Bricks made out of crushed steatite bonded by sodium silicate are used for the manufacture of furnaces . . . ."
http://www.mineralszone.com/minerals/talc.html
The metal retains the heat far better than any fabric.
This would be a good solution to use in a window(s) that you might not want to have wide open all the time, for the whole world to see into your house.
Also, this would be good for an area like my living room where, if I had all the windows completely uncovered, I wouldn't be able to see the TV because of the massive glare it would cause.
My living room, and bedroom blinds and/or curtains are always drawn for the above reasons.
A device like this would still allow me to use the sun, without all that annoying light...lol
AND... you are right about blocking the sun... theses panels do not need to cover the entire window; henceforth, allowing light to "still" enter the room... ya's got to love that.
Thanks for your comment!
An incandescent bulb (the old type with the filament) is a better heater than a light, a 100 watt light bulb still wouldn't give off as much heat as one of your panels. If you light the room with an energy saver light bulb of say 20 watts I would imagine you are still getting a net gain when it comes to saving energy on heating versus using energy for lighting.
GREAT instructable Mike.
But I can't help but wonder like a lot of people mentioned here before how this mathematically speaking would be any more effective then just leaving your curtains open and allowing black/dark furniture and the likes to accumulate the heat except for the miniscule amount of light that would be reflected back out of the room.
Although I have seen you attempt to support this claim a few times I can't say I find that to be scientifically sound answers which makes me uncerntain about the whole thing.
I mean sure I can understand how the "passive air heaters" attached to your wall would help seeing as they use passive space but that'd be an entirely different matter.
Now using something like sand or some special form of stone to store the heat for when the sun does go down seems a much sounder idea seeing as you can prove this principle would work based on easily identified/documented data on the subject of heat retention.
Another thought that struck me was this new idea that popped up last year or maybe a bit earlier about constructing solar panels with "maze like" indentationes/grooves in the material to increase the surface area that got radiated by the sunlight.
Wouldn't this principle be applicable to this sort of design, making it more uneeven and therefore increasing the surface area used to trap sunlight by, for an example simply sanding the material before coating it or if painting it allowing it to hang upside down so that it forms these kinds of spikes you see on "spray on cement" and such like?
I dont know how constructive my comment and idea will be but that's my "two cents" on the matter anyways.
I could go through the mathematics but I think this general principle should be easy enough to understand without maths and very well documented scientific formulas.
This is just a simple project... obviously, it is not for everyone.
Thanks for your comment though!
Nice Instructable! In expensive and easy to do.
To support your project Mother Earth News did something similar but different.
http://www.motherearthnews.com/Renewable-Energy/2006-12-01/Build-a-Simple-Solar-Heater.aspx
The great thing about your project is that it can be done by almost anyone, not just those that are good at construction. I believe you panels perform a function very much like those in the MotherEarth article but from an inside-the-house approach.
I think your approach had real merit. Thanks for sharing!
http://blog.imehrle.com/2011/02/10/solar-heating-made-easy----very-easy.aspx
Nice 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 the house 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 my country 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 the picture. 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
cheers,Sp9
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 great compared to using plexi-glass, and lots cheaper.
Great project!