[RE-wrenches] Array spacing for optimum performance

[Larry Crutcher, Starlight Solar Power Systems]

Carl, 

This answer does not address a shading issue but may be pertinent to your question. 

Due to the higher cost of electricity in Yuma, AZ in the summer, I installed an 18kW PV array with the elevation optimized for summer production. The utility company recently reported that the system is performing at 15% better than comparable sized systems. It may have to due with choice of components (very low temperature coefficient for power) but also due to the energy cost that is offset in the summer. So, even though the all year performance is compromised, it is still saving my customer more money annually.

Something to consider.

Larry Crutcher
Starlight Solar Power Systems
(928) 342-9103






On Apr 15, 2012, at 4:44 PM, Michael Welch wrote:

Carl is having sending issues, so I am posting this on his behalf. He will be able to receive your responses on the list, though.

From: Carl Emerson <Carl at solarking.net.nz>
Sent: 15 April 2012 10:16 p.m.
Subject: Array Spacing for optimum performance.
 
 Hi there,
 
Can I raise a design issue with large grid-tied arrays.
 
Using William’s spreadsheet for array spacing leaves me with several questions unanswered.
 
Assuming the array is inclined for max year round performance, one could then space the array for no shading for a certain sun Elevation and Azimuth.
 
The question I have is what is the sweet spot when compromising shading for array spacing in large arrays.
 
Narrower spacing means more panels in the array and better output in summer.
 
Wider spacing means better winter performance with less panels and less annual power production.
 
Is there a guideline available to optimise these factors…
 
Thanks for your help.
 
Carl Emerson
Freepower Co.
Auckland N.Z.



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