Hello everybody,

I am doing a study with a shading system with photovoltaics integrated into it. Since now, for the calculation of the energy output, I am using the Ladybug_photovoltaic Surface component in combination with the Ladybug_Sunpath Shading component to generate a derate factor to take into account for the self-shading of PV on the upper side of the blinds. I am testing the consequence in PV production of adding more blinds to the system, but I am getting strange results out of it. I did a set of simulation with 10 louvres up to 25 and checking the PV production, there is a linear increase in it, which is unrealistic since the louvres are getting more and more close to each other and the self-shading effect should result in a drop or stabilisation in the production over a certain optimal threshold.

I, therefore, tried to run the same set of simulations with another method, using the Ladybug_radiation Analysis component and then converting the total radiation in PV production through a formula that takes into account the efficiency of the modules and another couple of penalty factors. Here the results follow a more reasonable trend in my opinion, where the addition of extra louvres does not bring any great advantage due to an increase in the overshadowing effect.

My question is: why the method with the Photovoltaic surface in combination with the Sunpath shading is not giving convincing results? I do not see where I am making a mistake in setting it up. Do you have any clue about where the error is? I would prefer to use that one since it gives me hourly PV production results that I would like to have for making the system dynamic in a second step.

Here a couple of pictures of the two methods I am describing and a table and chart of the series of results for the two. The louvres are 20cm wide and 45Ā° tilted.

Thank you in advance for your help

Matteo