Site Design

TheElectrician

Senior Member
Hey Guys,

I was wondering how everyone here is designing their site plan for large commercial roof tops, especially how do you guys draw the shade from the objects in CAD?

What I do:

I use AutoCAD 2D to draw the layout and use shade calculation (Proprietary Tool) to estimate the shade based on the object height and then draw it out in AutoCAD and place them over every object on the roof (This literally takes soo much time to do!) So, I was wondering if there are any other tool available to create these shade crowns? (Check attached to see what I am talking about)
 

Attachments

ggunn

PE (Electrical), NABCEP certified
I used to use Sketchup with its geolocation and shade simulation to do this sort of thing. I built 3D models of the roof and obstructions, set the date for the shade simulator for the winter solstice, and swept the time between the beginning and end of the solar window I wanted to capture. Drawing in the outlines of the shadows at several points in time and overlaying them gave me the shading over the course of the day. One thing it yielded differently from what you have drawn is some concavity in the horizontal line across the top of the shading pattern.

Now we use drones and Scanifly to model roofs and generate TSRF numbers for module locations. It's a whole lot easier.
 

TheElectrician

Senior Member
I used to use Sketchup with its geolocation and shade simulation to do this sort of thing. I built 3D models of the roof and obstructions, set the date for the shade simulator for the winter solstice, and swept the time between the beginning and end of the solar window I wanted to capture. Drawing in the outlines of the shadows at several points in time and overlaying them gave me the shading over the course of the day. One thing it yielded differently from what you have drawn is some concavity in the horizontal line across the top of the shading pattern.

Now we use drones and Scanifly to model roofs and generate TSRF numbers for module locations. It's a whole lot easier.
Thanks man, I agree on the concavity, since its drawn manually on AutoCAD I don't get that. "I built 3D models of the roof and obstructions, set the date for the shade simulator for the winter solstice, and swept the time between the beginning and end of the solar window I wanted to capture. Drawing in the outlines of the shadows at several points in time and overlaying them gave me the shading over the course of the day" - You did all this with Sketchup?

Also, I looked at Scanify, it looks awesome and easy!
 

pv_n00b

Senior Member
I have used Helioscope for layouts and transfer that to CAD. Super easy and you can what if around with the shading limits to maximize the annual yield. With the cost of modules being low and the latest tech being more shade-tolerant you will get a higher annual yield by putting more modules on the roof and letting them be shaded during periods of low solar insulation during the winter. It's not like in the old days where even shade on the module during the Winter solstice was to be avoided.
Large commercial roofs are usually done with a drone survey these days. Then the 3D modeling can come out of that. While that can give you shading you still need to know how that affects the annual energy yield and that requires running everything through energy production software and packing in modules.
 

ggunn

PE (Electrical), NABCEP certified
Thanks man, I agree on the concavity, since its drawn manually on AutoCAD I don't get that. "I built 3D models of the roof and obstructions, set the date for the shade simulator for the winter solstice, and swept the time between the beginning and end of the solar window I wanted to capture. Drawing in the outlines of the shadows at several points in time and overlaying them gave me the shading over the course of the day" - You did all this with Sketchup?

Also, I looked at Scanify, it looks awesome and easy!
Yes, and it was a bit tedious, to say the least. After I had the 3D model built and the date set to the winter solstice, I would use the shade tool and change the time from beginning to end of the solar window, i.e., 8AM-4PM. in one hour increments, make a mark or two at the upper boundary of the shade at each time, and then connect the dots.

And yes, Scanifly is great. I just got back from a small commercial site assessment using a drone for imaging to feed Scanifly. We were on site for 15-20 minutes and no one had to get on the roof.
 

TheElectrician

Senior Member
I have used Helioscope for layouts and transfer that to CAD. Super easy and you can what if around with the shading limits to maximize the annual yield. With the cost of modules being low and the latest tech being more shade-tolerant you will get a higher annual yield by putting more modules on the roof and letting them be shaded during periods of low solar insulation during the winter. It's not like in the old days where even shade on the module during the Winter solstice was to be avoided.
Large commercial roofs are usually done with a drone survey these days. Then the 3D modeling can come out of that. While that can give you shading you still need to know how that affects the annual energy yield and that requires running everything through energy production software and packing in modules.
That is right. And I use Helioscope too, but you cant export the shade as an object when to export it to a CAD file. I need to show the shadings in my construction plan for the installers.
 

TheElectrician

Senior Member
Yes, and it was a bit tedious, to say the least. After I had the 3D model built and the date set to the winter solstice, I would use the shade tool and change the time from beginning to end of the solar window, i.e., 8AM-4PM. in one hour increments, make a mark or two at the upper boundary of the shade at each time, and then connect the dots.

And yes, Scanifly is great. I just got back from a small commercial site assessment using a drone for imaging to feed Scanifly. We were on site for 15-20 minutes and no one had to get on the roof.
Got it, I understand what you are doing. We actually started to use Drone Deploy recently, but it does not give you an interface like the Scanify to measure the heights of the obstructions or the building, It just gives a CAD file showing all the obstructions in the roof. I will try to use Scanify, may be set up a demo with them.
 

ggunn

PE (Electrical), NABCEP certified
Got it, I understand what you are doing. We actually started to use Drone Deploy recently, but it does not give you an interface like the Scanify to measure the heights of the obstructions or the building, It just gives a CAD file showing all the obstructions in the roof. I will try to use Scanify, may be set up a demo with them.
Tell 'em Gordon from Freedom Solar Power in Austin sent ya'. :D
 

pv_n00b

Senior Member
That is right. And I use Helioscope too, but you cant export the shade as an object when to export it to a CAD file. I need to show the shadings in my construction plan for the installers.
Why do the installers need to know the shade pattern? Unless they are doing module layout on the fly. I show the module layout and have not shown shade on a drawing in a long time. I think it just adds unnecessary clutter to the drawings.
 

TheElectrician

Senior Member
Why do the installers need to know the shade pattern? Unless they are doing module layout on the fly. I show the module layout and have not shown shade on a drawing in a long time. I think it just adds unnecessary clutter to the drawings.
We use the same drawings for our QA/QC and maintenance purposes. So it is a good record keeping for us to look back at designs. But yeah it does take a good amount of time to create them!
 
Top