I am running an energy analysis to show the impact of a shading device on cooling loads by source (direct solar, diffuse solar, conduction, people, lights, equipment, etc).

 

I ran it with and without the shading device. Despite a separate solar radiation analysis showing that the shade reduced the solar radiation hitting the window by over 60%, there is only a minor change in the "Zone Exterior Windows Total Transmitted Beam Solar Radiation Energy" and the "Zone Exterior Windows Total Transmitted Diffuse Solar Radiation Energy". 

I then ran the same simulation using Viper from DIVA 3 as a check. The total solar gain without the shading was about half of what ArchSim predicted. Additionally, the reduction in solar loads when you add the shading is about what I would expected. Can you help clarify what the issue could be? 

On a related side note: The ArchSim shading component is supposed to be always opaque when no schedule is applied. However, the default schedule is "AllOn" which I assume is a schedule of 1 values. Yet, the component notes also state that the schedule 0=opaque and 1=transparent. Indeed, when I ran it with the default schedule, it was if the shade was not there are at all. Only when I created a separate schedule of all zeros did it seem to register the shading.

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Elliot,

Can you post or send the .idf files for the "with shading" version of your Archsim model (those files are located wherever you are storing your simulation files) and the Viper one (in the "thermal" subfolder of your DIVA project folder)? Also I think seeing the Rhino and GH files would help to figure this one out.

Were you using the same two EnergyPlus output variables when evaluating solar heat gain in the two tests?

Jeff

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