[RE-wrenches] Inter row shading: Portrait V landscape

[Joel Davidson]

William,

Kyocera has info and diagrams about shading at http://www.google.com/imgres?imgurl=http://www.kyocerasolar.com/images/SI_shading2.gif&imgrefurl=http://www.kyocerasolar.com/solar/modules.html&usg=__yf6KqK_dUhhzxPEz7cw-kfYIu0E=&h=284&w=465&sz=9&hl=en&start=16&itbs=1&tbnid=6DoggLWqADx8LM:&tbnh=78&tbnw=128&prev=/images%3Fq%3Dpv%2Bshading%26hl%3Den%26sa%3DG%26gbv%3D2%26tbs%3Disch:1

(if this long address doesn't work, then go to google images for pv shading)

Premier Power's brochure at http://www.docstoc.com/docs/29007477/Residential-Solar-Power/ page 6 shows similar images and says shading the bottom row of a portrait module knocks out 100% of the module's output.

Joel Davidson
  ----- Original Message ----- 
  From: William Miller 
  To: RE-wrenches 
  Sent: Thursday, April 22, 2010 8:40 PM
  Subject: [RE-wrenches] Inter row shading: Portrait V landscape


  Friends:

  99% of the time, we install modules in portrait mode.  We find ourselves installing a set in landscape with some short inter-row spacing, due to roof vents.  We are using Solarworld SW230 modules.

  It is my understanding that shading the short edge of this type of module is much more detrimental to the output than shading a long edge.  This is because of the manner in which the cells within the module are arranged in series.  I understand that one string is on the bottom half of a module and the other on the top half of a module in the landscape orientation.  In order for the module to cease power production, you have to shade at least one cell from each of the two internal strings.  Therefore, you need to shade more than half of a module in the landscape mode before the module before the output declines drastically.

  Is my understanding here correct?  I will be testing this tomorrow if weather permits.

  Thanks in advance.

  William Miller



  Please note new e-mail address and domain:

  William Miller 
  Miller Solar
  Voice :805-438-5600
  email: william at millersolar.com
  http://millersolar.com
  License No. C-10-773985




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