Learning about Direct Coupling [RE-wrenches]

[Jeff Clearwater]

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Hi All,

I can imagine a cap/small battery buffer that would deal with this 
but then you'ld also have to have a way to supply grid AC when 
needed.  Like Jeff says it sounds like the hassle wouldn't be worth 
the expense but do you know otherwise?  Is this a seriously emerging 
industry?

jc


>"Direct Coupling of PV to lighting loads in commercial buildings. Has
>anybody had any experience with this? Anybody want to learn with me?"
>
>All fluorescent and HID commercial lighting fixtures require ballasts
>which are an AC device.  Of course you could use custom DC ballasts
>but that is not your main problem.  I think you will find the direct
>coupling of the pv array to the lighting loads without any kind of
>electrical "buffer" device to stabilize system voltage such as a
>battery bank, voltage regulator, or inverter, the voltage and currents
>will be all over the place and either destroy your ballasts or at
>least cause constantly changing light output levels.  What happens if
>a cloud passes over?
>
>You will also find it very expensive for retro-fit DC electronic
>ballasts in this size range.  Bottom line, probably cheaper to use
>grid tied inverter system and lower cost (but high efficiency) AC
>ballasts.
>
>Jeff Yago
>
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-- 
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
Jeff Clearwater
Village Power Design Associates
Sustainable Energy & Water Solutions for Home & Village

Office:  (413) 256-6777,  Cell: (720)480-8455 
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Council Member - Ecovillage Network of the Americas - http://www.ecovillage.org
Advisory Board - Living Routes - Ecovillage Education - 
http://www.livingroutes.org
Founder:  Ecovillage Research, Development, and Demonstration Program:
http://www.home.earthlink.net/~clrwater/RDD/rdd.html
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

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