Solar panel mounting angles

Posted by bp100a on May 25, 2004, 7:39 am

Is there any data on how the efficiency of a panel setup is affected by
changes in the mounting angle?

At my location the mounting angle should be approximately 40-41 degrees. I
would like to have panels on my roof flat-mounted, which is significantly
different than 40 degrees. How much would I be losing?

/harry

Posted by Miguel Gimenez on May 25, 2004, 8:46 am

There are computer programs that calculate the efficiency along the year
with varying angles.

You will loose about 40% per year (27% lost in week 26, 70% lost in week 52)

Best regards
Miguel Gim�nez

Posted by George Ghio on May 25, 2004, 1:13 pm

And when you are all done you can work out the losses during the warmer
times of year due to the temp of the panels.

Minimum single axis rack and reposition twice a year.

George

Posted by Martin Riddle on May 25, 2004, 8:02 pm

I believe its 2% for angle differences up to 20deg.

Cheers

Posted by Duane C. Johnson on May 25, 2004, 9:45 pm

Hi Martin;

Martin Riddle wrote:

The loss basically follows the cosine law:

100% - cos( angle ) = loss

30deg = 13.4%
25deg =  9.4%
23deg =  7.9%
20deg =  6.0%
15deg =  3.4%
10deg =  1.5%
5deg =  0.4%

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