Off-ideal Array Tilt Output [RE-wrenches]

[Bill Brooks]

===========================================================
Graduate in less than 13 months with AIU’s Online virtual 
campus. Classrooms and student service as close as your 
computer. Highly accredited, study anytime – anywhere.
http://click.topica.com/caab6anbz8Qcsbz9JC9a/ AIU
===========================================================



William,

The overall average wire losses should be about 75-80% of peak power because
for a typical system in the U.S. (except Alaska) 50% of energy is generated
above 800 W/m^2 and 50% of energy is generated below 800 W/m^2.

Bill.

-----Original Message-----
From: William Korthof [mailto:wkorthof at earthlink.net]
Sent: Monday, April 05, 2004 11:35 AM
To: RE-wrenches at topica.com; RE-wrenches at topica.com
Subject: RE: Off-ideal Array Tilt Output [RE-wrenches]

Interesting subject to bring up...

If your wire losses at peak power are 2%, your actual wire
losses will be significantly lower. At half power, the losses
would be half as much (1%). At 25% power, losses would
be one quarter (0.5%). The overall losses are the production-
weighted wire loses over the total production cycle. I think
the overall wire losses for a typical system would be maybe
50-60% of the loss at peak power.

/wk


At 08:28 PM 4/4/2004, Bill Brooks wrote:
>
>
>Don and Allan,
>
>The problem that Tim Townsend was having with PV Design Pro is that there
is
>a calculation bug in the program that overpredicts the impact of wire
>losses. Essentially, if your wire losses are 2%, it will calculate them to
>be 3 or 4%. This yields a more conservative production number which is
>generally erring on the right side of safety. However, his point is that if
>a bug is found, it should be fixed because it raises questions about the
>code in general. I think most people that use the program have been happy
>with it. However, if I used it (which I don't), I would feel much better if
>the bug was removed.
>
>Bill.
>-----Original Message-----
>From: Don Loweburg, Offline [mailto:i2p at aol.com]
>Sent: Saturday, April 03, 2004 10:45 AM
>To: RE-wrenches at topica.com
>Subject: Re: Off-ideal Array Tilt Output [RE-wrenches]
>
>
>In a message dated 4/3/2004 10:20:44 AM Pacific Standard Time,
>tony at appliedsolarenergy.com writes:
>According to my calculations: (using the weather data for Albuquerque)
>the annual total for tilt at 30 degrees, south is
>5420 kwh (for a specific combination of panels and inverter)
>and at tilt 26 degrees, azimuth 50 degrees west of south the annual total
is
>5002 kwh
>so the relative performance is 92.3%.
>
>
>
>I ran the simulation using PV Design Pro and got the result that the off
>south orientation yields 93 % of true south yield.  So at least our
software
>yields similiar results, now for the real world.
>
>In my experience the software is doing a good job for me predicting actual
>vs
>real output.
>
>
>Tim Townsend has some issues with Design Pro and the way the program sizes
>wire, but for me the real- theoretical is close enough --(a few percent
>generally)
>
>best, Don
>
>[Non-text portions of this message have been removed]
>
>

===========================================================
Your opinion counts! We’re conducting a survey for a 
computer service/repair company. When you complete our 
survey, you will also be entered into a drawing for one of 
ten $100 prizes. Just click
http://click.topica.com/caab6Pibz8Qcsbz9JC9f/ Val Rad
===========================================================
- - - -
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
--^----------------------------------------------------------------