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From: cage@fmeed1.UUCP (Russ Cage)
Newsgroups: sci.energy,sci.electronics,sci.physics
Subject: Re: solar cells
Summary: Tracker power drains are very small.
Message-ID: <9284@fmeed1.UUCP>
Date: 7 Jan 91 20:05:02 GMT
References: <1990Dec17.190857.16559@engin.umich.edu> <37448@cup.portal.com> <1755@cluster.cs.su.oz.au> <5173@optilink.UUCP>
Reply-To: russ@m-net.ann-arbor.mi.us (Russ Cage)
Followup-To: sci.energy
Organization: Ford Motor Co., Electronics Div., Dearborn, MI
Lines: 24

In article <5173@optilink.UUCP> cramer@optilink.UUCP (Clayton Cramer) writes:
>It used to mentioned as a problem on tours of Solar One.
[....]
>Also, they have lots of electric motors moving those mirrors
>to track the Sun.  How much electricity?  I was told while I
>was there in the early 1980s that they FINALLY were producing
>more electricity than they were using.

Even working against wind loads, the amount of power needed
to track the sun is minuscule.  1/10 HP is overkill for all
but the biggest arrays.  Rapid tracking to stow mirrors in
sandstorms would take more power, of course, but that is a
transient and infrequent requirement.

If the array catches 700 W/m^w and the system turns 20% of that
into electricity, each square meter produces 140 watts, or about
twice what the tracking motor needs.  If each part of the array
has 100 m^2 of area, then tracking takes about .005 of the
energy output; not negligible, but far from a killer.
-- 
Russ Cage	Ford Powertrain Engineering Development Department
Work:  itivax.iti.org!cfctech!fmeed1!cage   (CHATTY MAIL NOT ANSWERED HERE)
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