My dear Dr. Mohamed, I would be happy if you we meet any time to discuss your problem. I hope we could figure out the solution together.

Hi Guys, I have a similar problem. Would you please share your answer here online as well.

I have two electric load centers. One is for PV on roof of the building and other is for BIPV in the wall-construction of the south facade. My design objectives are

1. Min Electricity consumption

2. Maximize Electricity Generation.

My variables are the two load centres and the window to wall ratio.

The results of the optimization show that with smaller WWR, the electricity generation is also smaller (larger negative number). But this should not be the case as smaller window size should mean that the wall covers more area and thus the BIPV should generate more electricity.

The only reason I can think of is that the negative sign is only showing energy generation as opposite to energy consumption which is shown in positive digits.

Does this make sense?

Dear Prof. Mahmoud and Prof. Sardar,

Thank you so much for your help and support. The software developers seem to give a positive sign to energy consumption and a negative sign to the generated energy.

In DesignBuilder, energy consumption is represented by positive values and displayed in blue. This means the higher the positive value, the more energy your building is using. Conversely, generated energy, like from solar panels, is shown as negative values in green. So, a negative value with a green tint indicates your building is producing energy, which helps offset its consumption.