[Vo]:Re: Dual-Use solar panels?

[Michel Jullian]

Interesting idea Jones but it seems to me that it would be tricky to get a 
significant portion of the uncollected radiation to be reflected to the 
trough's focal line.

A different kind of PV-thermal hybride had crossed my mind: a solar water 
heater whose sunlight collecting surface would be made of solar cells. Since 
presumably most of the uncollected energy goes off as heat, this might have 
more chances to work, especially if the circulating water is not too hot e.g. 
swimming pool water (hybrid municipal swimming pool / municipal power plant?), 
as I believe PV cells run better when they are cool.

Michel

----- Original Message ----- 
From: "Jones Beene" <[EMAIL PROTECTED]>
To: "vortex" <vortex-l@eskimo.com>
Sent: Wednesday, July 09, 2008 6:40 PM
Subject: [Vo]:Dual-Use solar panels?


> This company:
> 
> http://www.g24i.com/
> 
> Has a thin film solar film panel that is flexible, and
> is claimed to be cheaper than the similar offerings of
> competitors due to lower requirement for rare elements
> like indium. It and others use a printed ink or dye,
> instead of silicon in the active layers.
> 
> Because of low conversion efficiency - less than 10%
> of received irradiation and often a 12-hour average
> below 5% - and the high installation costs for small
> users (which is always underestimated) and the
> maintenance and bad-weathering issues (glossed over by
> the manufacturers) - these printed panels will likely
> NEVER make good economic sense for most US home-owners
> - EVEN if the panel are given away (via tax benefits
> for instance) and are totally free. 
> 
> However, and surprisingly, there is a way that they
> (the flexible printed panels) can make a large - and
> possibly surprisingly large - contribution to daytime
> grid power and at competitive costs for large
> installations. Hybridization.
> 
> But that exact technique is hardly ever mentioned!
> Possibly because it is a combination strategy, and no
> one company stands to benefit from it yet.
> 
> To back-track a bit:
> 
> The lowest cost method for solar conversion now,
> according to the economic studies which I have seen,
> begins with a single axis parabolic trough. Yes, the
> new two-axis sun-tracking Stirling array - the Sandia
> design which is going into large-scale use is close in
> cost to the trough - with the advantage of being far
> simpler, since no steam plant is required. Here is a
> company claiming great things for solar Stirling:
> 
> http://www.infiniacorp.com/main.php
> 
> But the cost and performance edge still clearly goes
> to the parabolic trough collectors, which have evolved
> in Europe, Asia and Israel into significantly lower
> cost options; more so than in the USA. This is due
> partly to standardization and mass production - but
> mostly due to *political willpower* at the highest
> levels (which translates into lack of an oil lobby, or
> worse - no active Petromafia, flush with ill-gotten
> wealth, to deal with).
> 
> Anyway the point of this post is the explication of a
> possible hybrid - of the solar-trough with the
> printed-roll collector.
> 
> That hybrid as I conceive it, would begin with a cheap
> extruded but NON-mirrored parabolic trough, and over
> that base would apply a version of the flexible thin
> film panel, which can follow the curvature of the
> parabola.
> 
> The "ink" used, and the protective top coating,
> however, would be modified so that most of the solar
> irradiation, the spectra which cannot be collected by
> the inks used in the active panel is reflected back up
> to the trough to be used as heat to raise steam. This
> would require a slightly longer trough, since a
> portion of energy is not being reflected - but the
> contribution  of the direct conversion should make the
> hybrid more cost effective than before.
> 
> Jones
> 
>