Shading issues?

[mark da spark]

We have just been to look at a house which is located next to a park with trees to the east of it (well over 100ft). Shadows the south facing roof completely until nearly midday which it is then clear until sunset. The trees are decidous.

Now for the 100 questions.

What is the best option to quote for the customer?
What shading factor would you use from SAPS calcs?
Should we use bypass diodes and if so, how and which panel would you recommend?
Has anyone ever used the Day4 panels which are apparently great for shading areas (supplier sent us a brochure & watched demo on ***tube)?

Hope someone can help.
Thanks in advance.
Mark

 

[Worcester]

Has anyone ever used the Day4 panels which are apparently great for shading areas (supplier sent us a brochure & watched demo on ***tube)?

From the DAY4 Installation manual:

• Install Day4 Energy modules where they are not shaded by obstacles like buildings and trees. Pay attention to avoid partial shading by objects during the daytime.
• Do not operate the module if it is shadowed or otherwise covered in its entirety or partially by debris, leaves, tree branches, dirt, bird droppings, snow, ice and/or any other substance or objects capable of preventing the light from illuminating the front surface of the module in a uniform unobstructed manner (refer to section in this manual labeled “Notes on Installation”)
...
• Even the slightest partial shading, like from dirt deposits, will cause a reduction in yield. A module is considered “shadow-free” if it is un-obscured across its entire surface for the entire year. Even on the shortest day of the year, un-obstructed sunlight should reach the module.

That seems to contradict their sales brochure / data sheet! (sales people vs techies I guess)


Use a good quality panel with bypass diodes, split the area into a number of different strings each with it's own mpp tracker - do a shadow map of the roof or use the 3D in PV*SOL expert , or use smaller inverters, even consider the enecsys micro-inverters, they have a two panel one (360W) out later this month.

Have a look at the SMA OptiTrac video and consider an inverter with OptiTrac Global Peak.

If it's covered for up to half the day, you'll want to squeeze eveything out of it that you can.