More on solar ovensgreenspun.com : LUSENET : TimeBomb 2000 (Y2000) Preparation Forum : One Thread
I went to a store today to see their solar stove for tips on how to improve my stove. I mentioned earlier that the one I made got up to 185 degrees ( it looks lke the one attached the house in the diagram posted earlier. Perhaps someone could provide a link. The salesperson told me she got theirs up to 350. What was missing from mine was reflector sheilds. I'll try to describe it. Picture a pyramid with the top 1/3 cut off. Turn it upside down. Place it to surround glass area. You could easily do this with cardboard and the emergency reflecting sheild found in camping stores. One more idea; dark grey roof slate make good heat tiles, as they are flat and don't take up a lot of room, but do hold the heat.
-- King of Free Estimates (Your@town.USA), July 15, 1999
i recently purchased a product called Skypipe for transmitting light into a building. it uses a super reflective material called Silverlux - i dont know if this is a trade name or generic, but its probably the most reflective material i've ever seen. its expensive also. but it would make a 'great' reflector for a solar oven i believe.
anyone ever hear of this material?
-- lou (email@example.com), July 16, 1999.
Hope this helps--
The amazing Skypipe tubular skylight with 3M Silverlux
PACIFIC SUN LITE
-- Tom Carey (firstname.lastname@example.org), July 17, 1999.
Here in southern California we use a reflective panel against the inside of the windshield to keep the heat out of the car. It is sturdy and quite foldable. I was thinking this could be folded into the pyramid shape and would make a very effective solar collector for a box oven. Any thoughts?
-- Doc (email@example.com), July 17, 1999.
K F Estimates ; Just wondering if you raised your cooking space up off the botom of the cooker??? I did about 2" and that helped alot, to allow heated air to circulate around the food. Also the more items inside the cooker helps raise the temp. My cooker has reached 220 with only 2 tupperware containers in it and small ones at that.... Furie...
-- Furie (firstname.lastname@example.org), July 19, 1999.
Re: Silverlux or any other "super reflective" material other than aluminum foil.
It isn't worth the cost.
Just use plain aluminum foil, shiny side up.
Bare aluminum reflects over 90% of infrared energy (heat) anyway. See graph "Bare Aluminum Coating" at the bottom of this page: http://advancedoptics.co m/newpage4.htm -- The infrared region of the spectrum is from 0.8 microns to longer wavelengths, the right-hand side of the graph. Note that except for a minor dip near 0.8 microns, the reflection percentage is well above 90% in the infrared.
In Pacific Sun Lite's graph "Light Intensity Comparisons - Silverlux Specular Silver vs. Anodised Aluminum" on page http://www.skypipe.com/fea tures.html, note that:
(A) The comparison is biased in favor of Silverlux by contrasting it with anodised (or anodized) aluminum. Anodized aluminum is not bare aluminum like aluminum foil; it has been treated by a process which, among other things, reduces its reflectivity (which may be desirable in some applications). If the Silverlux chart had shown a comparison to aluminum foil instead of anodized aluminum, Silverlux wouldn't have looked significantly, if at all, superior in reflectivity.
(B) The figures at the bottom of the Silverlux chart apply to a multiple-reflection situation, but in most solar ovens most incoming rays will be reflected only once or twice before being absorbed. The fewer the reflections, the less important any small difference in reflectivity percentage.
On the Pacific Sun Lite page linked above, is the statement "Silver reflects the 'warm side' of the light spectrum, which results in more natural light. Aluminum reflects the 'cool side,' which is much less warm to the perceptive eye." This applies to visible light, but that's not what's doing the cooking in your solar oven. Also, that statement could have been truthfully worded like this: "Silver is far less reflective than aluminum on the blue end of the visible light spectrum. (Compare the graph for silver at http://www.opticoat.com/pro t_ag.htm with the graph for aluminum at http://advancedoptics.co m/newpage4.htm)". The blue end of the spectrum (0.4-0.5 microns) isn't important for cooking.
-- No Spam Please (email@example.com), July 20, 1999.
Regarding "extra reflective" Solar materials, I recovered my home-made Cookit Solar Panel Cooker with Mylar Space Blanket material (cost about $3) and it worked noticeably (*really noticeably*) better. Cooks bread in 2.5 hours now, never got hot enough before. I'm not saying that NoSpam is wrong, but I reckon if you're having inadequate heat problems it's worth a try. (Or maybe USA alfoil is shinier than Aussie!)
Regarding raising cooking dishes: I put mine on Alfoil coated blocks (the alfoil helps to keep the rays bouncing around until they strike the black pot) to raise the pots about 1.5 inches. I think this helps a bit but it's more a gut feeling than quantifiable.
-- Ron Davis (firstname.lastname@example.org), July 21, 1999.
Y2K, ` la Carte by Dancr near Monterey, California
Just in case anyone didn't already know this... it's not a good idea to have light on all the time in your closet or pantry. There's a good reason why these rooms tend to be in the center of the house with no windows. Light is not good for clothing or for stored foods. Turn on a light to get what you need, then turn off the light. In case of no electricity, this is a good application for a flashlight.
I know... the links were placed here because of the reflective material, but some may have considered these home "improvements," based upon the suggestion by the manufacturer that these were reasonable applications for the pipes.
-- OT_Dancr (email@example.com), July 21, 1999.
>I recovered my home-made Cookit Solar Panel Cooker with Mylar Space Blanket material (cost about $3) and it worked noticeably (*really noticeably*) better.
Do you mean that you put the Space Blanket material on the reflective surface of the flaps that bounce sunlight into the oven, or that you put the Space Blanket material around the oven box as thermal insulation to prevent heat from escaping through the sides?
My remarks about aluminum foil were aimed at use for the reflective surfaces that bounce sunlight into the oven, not at using aluminum foil for thermal insulation to keep heat from escaping the oven once it got in. I would agree that the Space Blanket material would be better than aluminum foil for thermal insulation.
>the alfoil helps to keep the rays bouncing around until they strike the black pot
This is exactly what I meant! The aluminum foil bounces the rays so well that one need not go to the expense of using any more expensive material to do this part of the job.
-- No Spam Please (firstname.lastname@example.org), July 21, 1999.
Oops, sorry about the excessive spacing in the previous post, more HTML practice required.
-- Ron Davis (email@example.com), July 22, 1999.
Actually, it's more like a crockpot idea, and a darn good one at that! 8-}]
-- Mac (firstname.lastname@example.org), July 22, 1999.
It is indeed a crockpot idea! Crockpot recipes are perfect for solar cooking!
-- Ron Davis (email@example.com), July 22, 1999.