ContextSrf vs WindowShade

Hi guys

I am trying to run some energy analysis with shading. Based on my results I see that ContextSrf does not make ALMOST any difference in solar gains or indoor operative temperature even though all windows were “covered” by shading (look at the example file, red group, the right one). Same goes for the surrounding buildings. They should cover much more solar gains than they do.

Using the EPWindowShade component makes a difference but the geometry is to limited for my purpose. If just the contextsrf component works I am good to go, otherwise I am really stuck. Please help me!!!





I’m not sure what are your expectations of change. I’ve made some tests with my local EPW and i get for sure differences. I internalized 4 sets of simulations for solar gains. You can see the results in the attached.Without context, with context, without shades on window and with.

Considering that the space is not so big, the windows either, i wouldn’t expect “huge” differences in the results.

I disconnected some radiance materials since HB complained they can’t be found. So check them.

-A. (1.5 MB)

HI Abraham

Thanks for giving it a shot. Unfortunately I can’t see the graphs due to some error in Ladybug 3D chart: 1. Solution exception:unsupported operand type(s) for -: ‘str’ and ‘str’. There is something wrong with the internalized data component. Maybe if you split the results to solar gains and temperature it will work. Another thing is that I don’t know what you mean by fixed shading etc. I ran the script couple of times with / without buildings / with shading that covered both windows.

Total solar gains for zone were as follows

With surrounding buildings: 1425 kWh

Without surrounding buildings: 1624 kWh

Without buildings, with HUGE shading 1324 kWh

If you look how the building is located regarding north, the gains, when turning on/off the buildings, should have completely different shapes and should occur in totally different hours. The surrounding buildings should cut down some of early hours gains, and all they do they cut down gains after midday, and a little in the early hours.

As for the shading that I just ran, it should cut down almost all gains and it doesn’t, take a look at the file.




You know better the conditions of the simulations.

What i would do in order to understand the quality/quantity of the results is testing a simple space with some parameters changing: Orientation, Window size, window shading, glazing type, with/without shading surroundings.

You also need to know, or at least know what to expect, from the results. Those that you wrote above look reasonable. But maybe the range isn’t. Hard me to say.

Not very helpful at the stage you are, i’m afraid …


Thanks again for the reply. I ran couple of test and below you can see the results in the file. I ran 4 test with my own shades:

no shade

full shade around the window

half of the shade on the top of the window

half of the shade on the bottom.

Then I ran two different shades both produced by EPWindowShades. First analysis was ran entirely through the EPWindowShades component, second was just using the created breps and running them through contextsrf component.

Looking at the results now I see that they give similar absolute results, but the difference between EPWindowShades-85 kWh and ContextSrf-136kWh is pretty big as a relative difference.

As a conclusion I need to revise my model and check some similar values. If I get anything unusual I will get back here. Thanks again

SHADING_ (1.11 MB)

Hello, can i get the file via email I cannot download the it said the page not exist or private. Thanks.

You can download that definition from the original discussion on the old forum: