[Greenbuilding] Solar electric configuration details

Tue Nov 21 17:48:48 CST 2006

larry could probably increase the annual output 30-50% with a tracker (at 
little i.e. 10%) cost increase and thus improve the payback to 25 years 
which is after al l a 4% after tax (taxfree) return .

----- Original Message ----- 
From: "William Revelle" <lists at revelle.net>
To: "Lawrence Lile" <LLile at projsolco.com>; <greenbuilding at listserv.repp.org>
Sent: Thursday, November 09, 2006 9:24 PM
Subject: Re: [Greenbuilding] Solar electric configuration details

> Lawrence,
>
> In your calculations, don't forget the strong seasonal effects on PV
> generation as well as consumption. That 5 hours a day figure is an
> average over the year.
>
> The most efficient air conditioner is one that is not turned on!
> High efficiency ceiling fans do a good job for many days of summer.
>
> We have a nominal 6400 watt system that produces between 4 to 34
> KWH/day depending upon the season and the weather.   Total production
> for the year (we live in Evanston, just north of Chicago so we have a
> bit less sun than St.Louis) runs about 5700 KWH or 80% of our total
> electrical consumption.
>
> I use the data that I have recorded over the last 3 years to
> demonstrate graphical data analysis on a page discussing the use of
> the R stats program in analyzing data.
>
> http://personality-project.org/r/r.plottingdates.html
>
> Ignore the R code on the page and just look at the graphs.  I show
> daily data (the individual dots) as well as various smooths of the
> data.  What is clear is that production is very seasonal as is
> consumption.
>
> You might want to visit a discussion of  our production/consumption
> at http://revelle.net/lakeside/lakeside.new/electric.html
>
> Is it economical? No. (Even with a $6/watt subsidy from the state for the 
> PV).
> Does it reduce our carbon footprint substantially?  Yes.
> Does it make other people want to reduce their electrical consumption? 
> Yes.
> Does it make other people want to reduce their carbon production? Yes.
>
> Good luck.
>
> Bill
>
>
>
>
>
> At 5:34 PM -0600 11/9/06, Lawrence Lile wrote:
>>  >Is there nothing you can do to reduce that 34 kWh a day?  The return on
>>
>>investment (to say nothing of payback) on CFL bulbs is 300% (before
>>taxes).
>>
>>The 34KWH/Dy is a wild guess estimate, based roughly on my current
>>house, from my memory which is fulla holes.  The new house should be
>>dramatically more efficient, it is set up for 100% fluorescent lights,
>>super efficiency AC, radiant heat not requiring a juice-sucking fan
>>motor, no electric appliances, and so on.  After a month or two I'll be
>>able to gauge my electric usage more closely, hopefully it will beat the
>>current house by at least 40%.  I move in December.
>>
>>CFL bulbs are great compared to incandescants.  They are wimpy compared
>>to high efficiency T-8 bulbs with good electronic ballasts.  The 4 foot
>>T-8 lamps can beat a CFL lamp by another 50%!  I'm using a lot of T-8's
>>in the new house.
>>
>>Back to the solar electric system:  I'm trying to figure out if this is
>>just nuts.  So far, I can't justify it on economics, Carbon, or anything
>>except reliable power and the Solar Grin I'd get driving up to my house
>>and seeing the solar electric panels on top of it.
>>
>>--Lawrence
>>
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>
>
> -- 
> William Revelle http://revelle.net/revelle.html
> 2815 Lakeside Court
> Evanston, Illinois
> Information on energy efficient houses
> http://revelle.net/lakeside/energy.html
>
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