Inverter Shoot-Out continues [RE-wrenches]

Bill Brooks billb at endecon.com
Mon Mar 29 08:46:03 PST 2004


===========================================================
Are you looking for savings on products you use everyday? 
Visit Quality Health today and see the coupons, free 
samples and special offers our members enjoy each and 
everyday.
http://click.topica.com/caab5n1bz8Qcsbz9JC9a/ Ivo Interactive
===========================================================

Ezra,

The focus of our work with the CEC is overall system value and I agree with
you that system performance is more important than any one component's
performance.

In order to determine the value of a system, one must consider many, many
things. Here are just a few:

1. System documentation--does it explain the installation well enough for a
qualified person to install it properly so it will work properly?

2. System hardware--is the system hardware (not just modules and inverters)
designed to last as long as the solar array--materials selection, quality,
etc...? In the case of the inverter, what is the expected life and what is
to be done when and if it fails?

3. System troubleshooting--if a problem occurs, how does the customer find
out that there is a problem and how easy is it for the service person to
troubleshoot the issue?

4. System performance--does the system perform as expected?

This performance issue is the portion we have been discussing. It is only
one of several important issues--but the longterm performance is certainly
the most important of all issues. How do you determine system performance?
One way is to characterize each part that impacts performance for a generic
system (not counting orientation, shading, and soiling which are site
issues)--the PV array and the inverter. Computer modelling of the array and
inverter can help provide some initial sense of matching and performance.
That's why we need the inverter test--to characterize it. Lastly, a one or
two month field test of the product is needed to validate that the model has
accurately predicted actual performance.

Of course this does not necessarily address system degredation and other
important issues, but there is data for accounting for these issues that can
be incorporated into long-term models fairly easily. When you get into
predicting performance in year 17, models are just educated guesses anyway.

Bill.

-----Original Message-----
From: Ezra Auerbach, DragonSun Consulting [mailto:ezra at lasqueti.net]
Sent: Monday, March 29, 2004 7:54 AM
To: RE-wrenches at topica.com
Subject: RE: Inverter Shoot-Out continues [RE-wrenches]

I guess I'll chime in.  In my view the issue is overall system
performance, and being able to certify systems which are reasonably
likely to produce the estimated amount of energy.  To me this means more
than a few real-world test labs given the climatic differences of North
America.  Of course the final arbiter of what a system does is energy
produced, yes I did say it.  I also agree that +/- 10% is way too loose
for PV manufacturers to rate at.

Already a trend is beginning for funding agencies to require accurate
production information (CEC accepted meters built into inverters are now
a 'feature' on some).  It is time for module manufacturers to tighten
their scales.

Regards,

Ezra


DragonSun Consulting
Morewater Road
Lasqueti Island, B.C. V0R 2J0

ezra at lasqueti.net
250 333 8650 voice

===========================================================
**** Bounces like rubber! Shatters like ceramic! ****
Discover Crazy Aaron's Thinking Putty in grown up 
handfuls. It's the creativity unleashing, mood enhancing 
desk toy!
http://click.topica.com/caab4CEbz8Qcsbz9JC9f/ Crazy Aaron Enterprises
===========================================================

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

Archive of previous messages: http://lists.topica.com/lists/RE-wrenches/read

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

Check out participant bios: www.mrsharkey.com/wrenches/

Hosted by Home Power magazine

Moderator: michael.welch at homepower.com
--^----------------------------------------------------------------
This email was sent to: michael.welch at homepower.com

EASY UNSUBSCRIBE click here: http://topica.com/u/?bz8Qcs.bz9JC9.bWljaGFl
Or send an email to: RE-wrenches-unsubscribe at topica.com

For Topica's complete suite of email marketing solutions visit:
http://www.topica.com/?p=TEXFOOTER
--^----------------------------------------------------------------







More information about the RE-wrenches mailing list