Newsgroups: comp.robotics
Subject: Solar Insolation Levels
From: steve.jones@mecheng.fullfeed.com (Steve Jones)
Path: brunix!cat.cis.Brown.EDU!agate!howland.reston.ans.net!gatech!rutgers!uwvax!gorgon!fullfeed!mecheng!steve.jones
Distribution: world
Message-ID: <af.6906.33.0NAF8FC6@mecheng.fullfeed.com>
References: <ykgcqc4w165w@sfrsa.com>
Date: Tue,  2 Aug 94 18:20:00 -0600
Organization: MechEng / American Society of Mechanical Engineers
Lines: 36


E>Message-ID: <ykgcqc4w165w@sfrsa.com>
E>Newsgroup: comp.robotics
E>Organization: SFRSA BBS 14.4K N81 415-648-6427

E> 
E>Can't find my reference for how many watts per square meter of 
E>convertible energy there is in sunlight at the earth's surface <I can 
E>figure out the effects of lattitude!>.  Anyone know this?  Also, last 
E>time I asked, it was said that the cheap solar cells were in the range
E>of  up to 6% efficient.  Anybody know what progress has been made in
E>the last  few years or so?
E>And how about the more expensive yet commercially available types?

E>Thanks.  Post or email    eds@sfrsa.com

E>Ed

Above the atmosphere (extraterrestrial) solar radiation equals approx. 
1367 W/m2.  What actual penetrates the atmosphere is approx. 1000 W/m2 
which is a good standard used by such organizations as the Nat'l 
Renewable Energy Laboratory.  What do you mean by "cheap" solar cells?  
Stable or field efficiency ranges at 4 to 11% for single and polycrystal 
 silicon cells, which are more popular and less expensive than more 
exotic, higher efficient cells.  Thin-film amorphous silicon cells range 
 in the 1 to 5% efficiency.  The most commercially available and yet 
least expensive for the highest efficiency cells will be the single 
crystal silicon cells.  There is current R&D work being done with TI 
spherical silicon cells which are supposed to possess higher 
efficiencies without the increase in costs.  Remains to be seen.

-Steve Jones, San Diego Gas & Electric Co.

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