specific annual yield

[Kashyap]

Hello 

I am facing some issues regarding the annual yield. In the east-west system and the south-facing system, there is a major difference after simulation for the same location, as you can see in the attached screenshot. Simulation is done in 2D. Can you explain why it's happening?

Thanks 

[Peter_]

Hi Kashyap,

The difference, Isn't that what you would expect? 

For an EW system : For each installed kWp  there would be 0,5kWp facing the east and the other 0,5kWp facing west.
sun comes up in the east and shines onto the east-facing solar panel, however not on the west facing panel.  
As the sun moves during the day in the afternoon both panels receive sun. And in the evening only the west-facing panel.

For the south system the full kWp is facing south. and would receive some sunlight all day long.

When we compare both cases it seems that over the year the total electricity produced per kWp (=specific annual yield) is higher for a southfacing system than an EW system at this location. (and configuration)

So if the specific yield is higher for a southfacing system, is there any reason to install an EW system ? 

in the case If you have limited area, for example on a flat roof, then you could install more kWp on the same area if you use EW system compared to South system.
And because you can install more kWp on the same roof despite having a lower specific annual yield, your total yearly yield would still be higher than if you had chosen a southfacing system.

Hope it helps you ,

kind regards,

  Peter