ORIENTATION GUIDE FOR ROOF MOUNT PANELS

[Barry Fields]

When a person seeks to install solar panels on an existing roof, there are several factors to consider.

I have attached what I used to evaluate my installation.
   (attachment 1)  Diagram with My parameters.
   (attachment 2)  Blank form for anyone wanting to try it. [I used PAINT to draw and move things around].
   (attachment 3) The source worksheet I used to develop the Bullseye Diagram.

STEP 1
On attachment 1 (my roof) , I first entered the required data.
Longitude - used to determine time of day performance and Solar Noon variations inside a time zone
Latitude - used to determine seasonal performance
Roof orientation - used to adjust of day performance
Roof pitch - used to adjust seasonal performance.

STEP2

calculate pitch offset from latitude, mark it on the small vertical scale and move it to line that mark up with 90°

STEP3
calculate your time zone adjustment and move the time zone scale to the right by that amount.

STEP 4
move bottom most scale to align 00 with your roof orientation degrees on the time zone scale.

STEP 5
draw the horizontal & vertical lines as indicated and align the seasonal chart to align with the horizontal.

PRESS SAVE and Print.

My install shows a slight favoritism to spring/fall. It also shows a deficiency in AM performance. That is why I just recently added additional panels facing east. (see my previous post)

I hope this might be of assistance to someone else. Comments welcome.
(I do realize this does not account for temp extremes . It is intended to be a "ball park" guideline)

[Barry Fields]

Just an example I did for a neighbor to show the difference between mounting the panel flat on his inclined roof VS adding some more inclination.