Unisolar Roofing [RE-wrenches]

[Carl Emerson]

Bill Brooks wrote:

> Carl,
>
> How long did you wait for the a-Si to "attenuate?" It has a major impact on
> your results. Even 90 days is on the short side.

Yes, Bill your caution is absolutely correct.

Testing in Indonesia (by Fukae Lim Tamechika and others) of the triple junction
panels showed that it took 2000 hours of full sun for the power curve to
flattened out.
It should be noted that this soaking test that took 2000 hours for the panels to
stabilize was under intense sun simulation. For the academics, the conditions
were AM 1.5, 1 sun, 50 degrees cell temperature maintained throughout. Over this
period the samples averaged an 18% degradation before stability.
In my view, in the real world, I would wait one year outdoors to be sure that
stability was achieved.
For this reason and this is very important with these panels, I always do the
system design based on about 100 watts out of a US64 or EF2-64 roofing module
because the first season of sun will produce those power levels and you don't
want to cook the regulators MPPT inverters or whatever. In fact the insolation
levels in NZ can be as high as 1300W/M2 mid summer, well above the rated level
of 1000W/M2. This is partly because of the ozone hole over this part of the
globe.

For these reasons a period of soaking preceded the tests we made.

> Also, the test set you put together is for an off grid application. Any low
> fill factor module will tend to perform better under those conditions.

Yes again, at the time grid tie was unknown in New Zealand.

>  There are so many factors that influence how a PV module will perform, that
> it is important to be clear about how transferable a certain test is to other
> applications and other areas.
>

Totally agree. Typically in NZ for example the peak performance is somewhat west
of True North simply because we tend to have a lot of early morning fog and
clear evenings.

I am convinced that an important factor is the ratio of clear vs cloudy days on
annual average. This is because some panels absorb more handle Global insolation
better than others.

>
> Right now, we need tests for grid-connected equipment in California. I'm not
> really concerned about who outperforms who in the Netherlands (but I'm sure
> they do there). I want to know what happens here, and what the implications
> are for our market in California. If that benefits New Zealand, Canada, or
> the Netherlands, so much the better.

Sure... my experience can help in some ways but at the end of the day you need
some real world testing over there.

To those who have asked for the summary of results , be patient It will take a
day or two to get it together.
--
Regards,


Carl Emerson
Manager
FREEPOWER LTD.  "Harnessing Natural Energy"  Auckland, NEW ZEALAND.


- - - - - - -
To send a message:
 RE-wrenches at topica.com

The archive of previous messages: 
 http://www.topica.com/lists/RE-wrenches/

List rules & etiquette:
 http://www.mrsharkey.com/wrenches/etiquete.htm

To unsubscribe send a message to: 
 RE-wrenches-unsubscribe at topica.com

To check out the other RE-Wrench participants:
 www.mrsharkey.com/wrenches/index.html

Hosted by Home Power magazine: 
 www.homepower.com

For info contact list moderator by email:
 michael.welch at homepower.com

____________________________________________________________
T O P I C A  -- Learn More. Surf Less. 
Newsletters, Tips and Discussions on Topics You Choose.
http://www.topica.com/partner/tag01