Please Register and login to reply and use other advanced options
Posted by Winston on February 17, 2012, 12:40 am
j wrote:
(...)
> http://wims.unice.fr/xiao/solar/diy-en.pdf
Wow! Lots of detail in that report. Thanks!
> Since you have the mirror source. Although you can get metalized mylar cheap.
If I were to make that sort of collector, I'd consider a sheet
of aluminum Coilzak lighting sheet. It has the specular surface
already and would form a parabola easily.
> I had thought of doing an acoustic stirling (or a simple variation), but the
amount of dead clear days is too few here,
> and the complexity, too much. > There is a lot to be said for simple ideas that work! Like your reflector and
fan!
So far, the reflector has not moved much heat. The experiment was a success,
but the technique falls far short of adequate performance. :)
I suspect that these Heat Grabbers would work much better:
<http://www.motherearthnews.com/Do-It-Yourself/1977-09-01/Mothers-Heat-Grabber.aspx>
<http://www.motherearthnews.com/Nature-Community/1978-09-01/Mothers-Fluorescent-Tube-Solar-Collector.aspx>
--Winston
Posted by Jim Wilkins on February 16, 2012, 10:29 pm
> Jim Wilkins wrote: >> ... > That is high tech, Jim!
Whatever is appropriate. I can be VERY high-tech if someone else pays for
it.
> Right now, I'm experimenting with solar reflectors. > I have some surplus acrylic mirror material taped to some MDF > which is propped up on a step ladder. It reflects solar > energy from the back yard into the kitchen/living room area. >... > Curiously, aluminum foil did not reflect nearly as well as I'd > hoped. The crinkly surface puts too much power at inconvenient > angles. Also, I find that plain (non-mirror) acrylic appears > to work nearly as well as does the expensive 'mirror' stuff > in reflecting sunlight.
I've had an acrylic mirror outdoors exposed to rain (but not sun) for about
ten years, and it's still in good condition. It was a truck mirror repair
kit from WalMart.
> I've had an acrylic mirror outdoors exposed to rain (but not sun) for about > ten years, and it's still in good condition. It was a truck mirror repair > kit from WalMart.
The mirror - coated acrylic appears to be much flatter than the
uncoated stuff. The reflection from the uncoated acrylic pieces
are highly distorted. I don't suspect this matters much though.
Upthread, I conceded that a separate solar absorber box would
probably work very much better than my reflector idea did.
--Winston
Posted by Vaughn on February 16, 2012, 8:48 pm
On 2/16/2012 10:06 AM, Jim Wilkins wrote:
> The water heater is a tank at ground level with no external plumbing, fill > it with a hose through a backflow preventer and carry hot water to the > washing machine in a bucket. In addition to being much cheaper to build this > way it causes no damage when it leaks and it can't contaminate the household > water supply.
I remember when square bathtub-type solar hot water heaters were common
on roofs of older homes in the south Florida area. They were little
more than a black tar-coated tank of water on the roof. I assume they
were unpressurized. They likely had a toilet-style ballcock to keep them
full, and served the house through gravity feed.
There was no separate solar collector, the tank itself serves as the
"collector". Inefficient, but cheap and reliable.
As for the naked PV cells that the OP asked about, In a world where a
careful buyer can purchase panels for 1 dollar/watt, I would need to buy
them at far less than 50 cents/watt to bother with them. The best
homebuilt panel is probably inferior to the crappiest factory built unit.
Vaughn
Posted by Curbie on February 16, 2012, 4:55 pm
This on-line book goes into the fine detail of building PV panels:
"Build Your Own Solar Panel" $2.95
by Phillip J. Hurley
http://www.goodideacreative.com/solarpanel.html
Table of contents:
http://www.goodideacreative.com/spcontents.html
Although, I like the encapsulated method of moisture sealing PV panels
better as shown here:
Curbie
> Having previously had no interest in PV solar, I am now somewhat >intrigued. >I've noticed a huge number of tabbed and untabbed cells. Some that are >advertized as almost whole for prices under $.50/W. Some that are grade >A whole for ~$.70/W. >I am not sure what you do with these. Does it need glazing over it? >I've got a couple of potential uses. One is that I know of a few people >living off grid, who struggle with simple things like getting cell >phones charged. Or recharging AA and AAA batteries. Voltage input >tolerance for 12V source chargers is wide. >The other is that I have a location here where I was going to set up >domestic hot water, I have about 120SF of such. Solar could run the >pumps, although low power DC pumps are pricey. >But it seems a bit crazy, but it is little money crazy. Throwing a >couple hundred bucks at crazy is not the same as throwing a couple thousand. >Thoughts? > Jeff