Geez Joel, we need to start a solar museum for all the cool old stuff
you have.
I just did a bit of research, and it seems lux is a weighted measure
based on visible light present, while irradiation is more a total power
measurement. I guess we really need to have two different meters to
measure how much light passes through a module.
If we were to go a step further and characterize the quality of light
present, we might need a spectral analyzer to determine whether its
"cool white" or "daylight", etc. As always, the more you think about
something, the more complicated it becomes.
Ray Walters
On 11/3/2011 11:39 AM, Joel Davidson wrote:
See-thru solar cells have been around for decades. Arco Solar made 4%
efficient amorphous silicon modules and car sunroofs in 1984 that were
tinted brown like sunglasses. I got a 12-inch square see-thru laminate
that still works.
I also have a 6.75-inch square sample of MSK Corp's amorphous silicon
PV-TV solar panels. They were developed in conjunction with Kaneka and
Japanese architects Taiyo Industries. The full-size glass panels,
measure 1-meter square. In addition to producing electricity, they
provide thermal insulation, solar heat gain protection and protection
from ultra violet rays. During the manufacturing process, a laser
inscribes a series of ultra fine lines onto the panel to allow 10
percent of visible light to be transmitted through the glass, enough
for sufficient light to enter a building even during cloudy conditions
while protecting against excessive solar gain. Amorphous silicon solar
cells with 10 percent, 5 percent or 1 percent transparency are placed
between two sheets of glass to generate power. This solar panel
is called PV-TV because it is also used as a display screen on the
outside of buildings. See
http://www.metropolismag.com/story/20040727/pv-tv-a-multifunctional-eco-friendly-building-material
The Tiger Woods Learning Center in Anaheim and other buildings have
see-thru Schott solar modules with different amounts of transparency.
See
http://www.solardesign.com/library/pdf/tiger-woods-solar-curtain-wall.pdf
Also, opaque cell solar modules are manufactured with various cell
spacings for BIPV applications.
I have a Mastech Light Meter LX1010B in my tool kit for measuring lux.
This handy tool costs around $20.
Joel Davidson
----- Original Message -----
*From:* Keith Cronin <mailto:electrich...@yahoo.com>
*To:* Phil Undercuffler <mailto:solarp...@gmail.com> ; RE-wrenches
<mailto:re-wrenches@lists.re-wrenches.org>
*Sent:* Wednesday, November 02, 2011 9:50 PM
*Subject:* Re: [RE-wrenches] Bifacial modules
Thanks everyone for the feedback!
Thinking that the manu's can space cells accordingly on the
surface of the glass and create whatever % light the end user
wants to seep through.
The % of light must slide between 5-15%, depending on manu's
specs. Architecture can meet solar and increase the applicability
of the products.
Perhaps someday, they can make the cells see-through (or almost),
like glass.......? Now that opens up possibilities!
Aloha,
Keith
------------------------------------------------------------------------
*From:* Phil Undercuffler <solarp...@gmail.com>
*To:* Keith Cronin <electrich...@yahoo.com>; RE-wrenches
<re-wrenches@lists.re-wrenches.org>
*Cc:* Bill Brooks <billbroo...@yahoo.com>
*Sent:* Wednesday, November 2, 2011 9:18 AM
*Subject:* Re: [RE-wrenches] Bifacial modules
We've got an array of Silicon Energy modules "out back," and in
the interests of scientific discovery and procrastinating from
what I really am supposed to be doing, Kelly, Seth and I just ran
a few experiments to see if we can quantify the amount of
irradiation that makes it through the array.
Using a Kyocera module as our reference, we measured ISC with the
module in the plane of the array, then moved the module to the
same orientation but approximately 12 feet behind and in the shade
of the SE array, and again measured ISC. Sun conditions were
light wispy clouds, guesstimated 800 W/M2 (pretty darned good for
Arlington WA this time o' year), 10:30 local time. We measured
5.9A ISC in front of the array, and 610 milliamps when in the
shade the array, leading us to say that just over 10% of the
available sun will make it to your orchids.
It should be noted that there is a opaque backing behind each SE
cell, so the only light that makes it through is through the
intercell gaps. I've used Sanyo doubles before, and in those
modules the cells are slightly translucent, so the sun is somewhat
visible through the body of the cell itself as well -- sort of
like looking through very dark sunglasses. In either case, the
illumination on objects behind the array is a dappled, dynamic
light. As Bill says, it's pretty cool from an aesthetic point of
view. My personal .02 is that there is no finer place to put an
array than a shade structure using clear modules. It keeps
everything off the roof, gives shade and makes for a premium
installation option.
Phil
-----------
"When we learn how to store electricity, we will cease being apes
ourselves; until then we are tailless orangutans. You see, we
should utilize natural forces and thus get all of our power.
Sunshine is a form of energy, and the winds and the tides are
manifestations of energy. Do we use them? Oh, no! We burn up wood
and coal, as renters burn up the front fence for fuel. We live
like squatters, not as if we owned the property.
There must surely come a time when heat and power will be stored
in unlimited quantities in every community, all gathered by
natural forces."
-- Thomas Edison --
On Tue, Nov 1, 2011 at 7:48 PM, Keith Cronin
<electrich...@yahoo.com <mailto:electrich...@yahoo.com>> wrote:
Bill
Appreciate the feedback. One of the questions that I'm seeking
to determine- how much light will filter through the spaces
between the cells to the surface below?
Lets say for someone that wants to grow orchids- they need low
light, as an example.
Wondering how much light is diffused through the panels to be
able to do things like grow orchids and or have filtered light
to work?
As an example: Do any of you have irradiance measurements on
any carports that have done bifacials and determined how many
watts sq m are below?
Keith
------------------------------------------------------------------------
*From:* Bill Brooks <billbroo...@yahoo.com
<mailto:billbroo...@yahoo.com>>
*To:* 'Keith Cronin' <electrich...@yahoo.com
<mailto:electrich...@yahoo.com>>; 'RE-wrenches'
<re-wrenches@lists.re-wrenches.org
<mailto:re-wrenches@lists.re-wrenches.org>>
*Sent:* Tuesday, November 1, 2011 11:44 AM
*Subject:* RE: [RE-wrenches] Bifacial modules
Keith,
This is easy to test. Simple take an irradiance sensor, turn
it upside-down and test the irradiance on the bottom surface
of any PV array. It will vary greatly based on exposure to
reflected light and so on, but it will rarely be above 100
W/m^2. 10% improvement is an absolute maximum for any bifacial
technology, and that is on the high side. Any claims above 10%
are ignoring the physics of sunlight, reflectance of typical
materials, and PV.
Nothing wrong with bi-facials. They are beautiful to look at.
I would buy them based on aesthetics, not on performance.
Bill.
*From:*re-wrenches-boun...@lists.re-wrenches.org
<mailto:re-wrenches-boun...@lists.re-wrenches.org>
[mailto:re-wrenches-boun...@lists.re-wrenches.org
<mailto:re-wrenches-boun...@lists.re-wrenches.org>] *On Behalf
Of *Keith Cronin
*Sent:* Tuesday, November 01, 2011 1:04 PM
*To:* RE-Wrenches
*Subject:* [RE-wrenches] Bifacial modules
Hi
Was wondering if any of you have installed bifacial modules
and know what the % of light that comes through to a surface
below the modules?
Looking for a canopy type of installation/ application and
wondered if you have any #'s?
Thank you~
Aloha,
Keith
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