It appears that your shades are functioning as a solar collector system. When you eliminate the front shade, you open the closed box. You may be able to change
this behavior by not connecting your shade elements (apparently E+ is making them a sealed box).
Ned Lyon, P.E. (MA, WV)
Staff Consultant
SIMPSON GUMPERTZ & HEGER
781.907.9000 main
781.907.9350 direct
617.285.2162 mobile
781.907.9009 fax
www.sgh.com
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From: EnergyPlus_Support@xxxxxxxxxxxxxxx [mailto:EnergyPlus_Support@xxxxxxxxxxxxxxx]
Sent: Wednesday, December 13, 2017 7:37 AM
To: EnergyPlus_Support <energyplus_support@xxxxxxxxxxxxxxx>
Subject: [EnergyPlus_Support] Overlap shading - window heat gain without shading higher than using 80% transmittance shading [2 Attachments]
Hi All
I found a problem while simulating the shading surface in EnergyPlus.
I would like to simulate a model as can be seen in picture 1 below. The model has opaque shadings on the right, left, upper side and in the area between the window, plus a shading with
transmittance in the front area. (picture 1 - I set the model to be transparent so that all the shading device can be seen).
Basically, I would like to know how much the window heat gain reduction can be obtained by varying the transmittance on the front shading. I assumed that the higher the transmittance the
higher the window heat gain will be.
However, after doing several simulations, the result was not as I expected. The result showed that the window heat gain obtained by using the 80% transmittance front shading is higher than
without using the front shading at all. Besides, I also checked whether the heat gain will also be lower if I set to 99% (near 100%) transmittance. But, the result showed that the 99% transmittance front shading has higher heat gain than the 80% transmittance
(as expected). I also check if the result will be different if I set the transmittance to 100% (transparent), without deleting the shading object in the model. But, it showed the same result as deleting the shading.
After trying to fix this error, I found that by deleting the vertical shadings which are placed between two windows (see picture 2 � without the vertical shadings), this error can be solved.
So, I guess this error occurs because there is an overlap between those shading surface objects.
Thus, I would like to ask if anyone here ever find the same problem (error) before? Does it correct that this vertical shading is the reason of this error? Or is there any other explanation?
How can I fix this error without deleting those vertical shadings that I mention above? Because my actual model will have this shading and I would like to include those shadings in my model.
Maybe anyone here has any idea of the other way to simulate my model.
Thank you so much!
Cheers
Nurul
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Posted by: "Edward G. Lyon" <EGLyon@xxxxxxx>
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