[RE-wrenches] Bifacial modules
Ray Walters
ray at solarray.com
Thu Nov 3 11:54:19 PDT 2011
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:electrichi01 at yahoo.com>
> *To:* Phil Undercuffler <mailto:solarphil at gmail.com> ; RE-wrenches
> <mailto:re-wrenches at 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 <solarphil at gmail.com>
> *To:* Keith Cronin <electrichi01 at yahoo.com>; RE-wrenches
> <re-wrenches at lists.re-wrenches.org>
> *Cc:* Bill Brooks <billbrooks7 at 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
> <electrichi01 at yahoo.com <mailto:electrichi01 at 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 <billbrooks7 at yahoo.com
> <mailto:billbrooks7 at yahoo.com>>
> *To:* 'Keith Cronin' <electrichi01 at yahoo.com
> <mailto:electrichi01 at yahoo.com>>; 'RE-wrenches'
> <re-wrenches at lists.re-wrenches.org
> <mailto:re-wrenches at 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-bounces at lists.re-wrenches.org
> <mailto:re-wrenches-bounces at lists.re-wrenches.org>
> [mailto:re-wrenches-bounces at lists.re-wrenches.org
> <mailto:re-wrenches-bounces at 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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