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Problem Set #1 Exercise #1: Modify the question with different variables and post it here.

posted Mar 04, 2012 22:42:23 by SolPowerPeople
Rewrite the question changing the variables any way you'd like and then repost back here to share with other participants.
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7 replies
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SolPowerPeople said Mar 05, 2012 03:51:11
Alternate Problem Set #1 Exercise #1

You are designing a ground mount PV array at 30°N Latitude with multiple rows that faces true south. The tilt of the modules are 20°. The width of the modules are 39 inches and they will be installed in landscape layout. What is the closest distance the rows of the modules can be and not cause any shade during the hours of 8AM and 4PM solar time?
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SarahRaymer1 said Mar 05, 2012 22:13:59
Try this one:
You are designing a PV array on a flat roof in Santa Fe, NM. You have multiple rows facing true south with a tilt of 35 degrees.
You want to optimize your design for no shade during the hours of 7:30am to 4:30 pm.
Your modules are 36" wide, and laid out in a landscape formation.
There is a ridge around the rooftop that is 3' high.
How far in from the edge must your modules be to prevent the wall from shading the array? How far apart must your rows then be to prevent them from shading one another?
:)
I have posted illustrations to my answer for the alternate problem above from SPPI on my facebook page.
My answer came to 39.5" .
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SolPowerPeople said Mar 06, 2012 03:46:23
Hi Sarah, just out of curiosity, which sun path chart did you use to solve the alternate problem? (looks like you might have used 40N instead of 30N).
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SolPowerPeople said Mar 06, 2012 21:22:06
Okay, now here's another question (expect to see something like this on the test).

What is the pitch angle of a 2/12 roof?
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SarahRaymer1 said Mar 09, 2012 02:53:09
Well, I used a sun path chart from a class I took in the past... let me see... Holy Moly! Don't do what I did! After reading the Solar Pro article by Ken Gardner I was so excited that I could do this, and then I read the chart wrong. Let this be a learning lesson for me and for the rest of you all. Take your time when you write down your numbers! Argh!
Another lesson: if you take the time to try to explain it to someone else, it will often help it make sense to you. I was having trouble visualizing the 2nd part of the equation. I was out on a walk with my boyfriend, and I was pointing out at the horizon as I tried to explain the Solar Azimuth- and it came to me with clarity. You have to determine the LONGEST shadow length and design for a shadow occurring at ANY time in the day, at any place in the solar window!
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SarahRaymer1 said Mar 09, 2012 03:05:01
Since a slide show has already been posted on the 2/12 question, I would like to add one of my own for good measure. This is another fun visual problem.
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SarahRaymer1 said Mar 09, 2012 05:34:36
Did anyone try my wacky problem from above:

You are designing a PV array on a flat roof in Santa Fe, NM. You have multiple rows facing true south with a tilt of 35 degrees.
You want to optimize your design for no shade during the hours of 7:30am to 4:30 pm.
Your modules are 36" wide, and laid out in a landscape formation.
There is a ridge around the rooftop that is 3' high.
How far in from the edge must your modules be to prevent the wall from shading the array? How far apart must your rows then be to prevent them from shading one another?

It was a real doozy.
I'm posting images of it all worked out on my blog at abundancesolar.com, as well as a better solution for a design problem.
Please feel free to contact me to explain it if you like.
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