Re: [Vo]:Re: 70% solar panels

[R C Macaulay]

Whoa! Michel... say that again.. I'm missing something. My feeble mind 
cannot grasp the physics of attaining anywhere near this output.. unless.. 
well.. err...wez talkin about Dime Box saloon poker playing rules where both 
cards and whiskey can stretch the imagination.
Richard
----- Original Message ----- 
From: "Michel Jullian" <[EMAIL PROTECTED]>
To: <vortex-l@eskimo.com>
Sent: Tuesday, July 15, 2008 8:13 PM
Subject: [Vo]:Re: 70% solar panels


Nope, 1000 W per m^2 at normal incidence is all there is to it. Per square 
centimeter that's 1000/(100*100) = 0.1 W, so as the wiki you quote says 
(quite clearly I would have thought) you need 2300 times that, which you can 
obtain e.g. by focussing sunlight with a concentration factor of 2300:1, to 
get 230W on a square centimeter...

Michel

----- Original Message ----- 
From: "Brian Prothro" <[EMAIL PROTECTED]>
To: <vortex-l@eskimo.com>
Sent: Wednesday, July 16, 2008 2:02 AM
Subject: RE: [Vo]:Re: 70% solar panels


Now in my meager understandings in this area, I thought the 1000watts per
square meter is defined as a narrow "1 nm bandwith" of sunlight and is "a
measuring standard" not the full power falling on the surface of the 
Earth.
(The bands defined from below 400nm to 1700nm.)



The test measurement is partially described as;

"The ASTM G173 spectra represent terrestrial solar spectral irradiance on 
a
surface of specified orientation under one and only one set of specifed
atmospheric conditions. These distributions of power (watts per square 
meter
per nanometer of bandwidth) as a function of wavelength provide a single
common reference for evaluating spectrally selective PV materials with
respect to performance measured under varying natural and artifical 
sources
of light with various spectral distributions..."

"



So, if a panel absorbs multiple bands and is more efficient, as DBK seem 
to
have resolved thru engineering, then there is more power.  I also saw
mentioned they work well in low light? (might be poor rcall on my part.)



Now I am not an expert here, but the wiki says the power per square
centimeter is 230 watts:

"One sun" is a measurement equal to the solar power incident at noon on a
clear summer day. I.e. in a 2300 sun system, approximately 230 watts per
square centimeter are concentrated onto the cell system.[14]



Does the Additional multiple junction solar technology not tend to be far
higher in production that the normal 15%?  DBK claims Five levels.



I will ask DBK this directly...



FYI -here is a chart of all current peak outputs for various technologies
for solar cells

http://en.wikipedia.org/wiki/Image:PVeff%28rev110707%29d.jpg



Brian Prothro





-----Original Message-----
From: Michel Jullian [EMAIL PROTECTED]
Sent: Tuesday, July 15, 2008 5:41 PM
To: vortex-l@eskimo.com
Subject: [Vo]:Re: 70% solar panels



1/ Making use of 70% of wavelengths doesn't mean 70% efficient!



2/ From the details you provide it seems that the panel has an embarked
battery, which is fed by the ~200 W solar cells, and which is feeding a 
3kW
inverter. This allows them to claim 3kW for the panel, which indeed it can
provide, but of course not more than 200/3000 = 7% of the full insolation
time as they conveniently forget to specify.



They probably hope some people will be gullible enough to believe it can
provide 3kW full time, while receiving only 1.3kW solar irradiation!



I see no reason why the product can't be a good one BTW, apart from the
misleading way in which they present it.



Michel




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