To Shade or not to Shade is the question...

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Refering to Appendix G Table G3.1 exceptions: It is pretty straightforward that permanent shading devices, overhangs/projections, and automated blinds can be modeled for the Proposed Design building envelope. AND that the shading projections on the Base Building Vertical fenstration cannot be modeled......This leaves alot open for interpretation then. If permanent structures/hills/mountains can be modeled as a permanent "shading device" on walls/roofs/windows, then it can be used to your advantage on the Proposed case, but what of the baseline? Note that I did not mention trees/bushes which can be argued to outlive the building useful life. Shading is only activated when there is a window (Trace700), so can/should you model shading on the exterior wall surface? 90.1 does not address the walls, just the windows. If I model the permanent shading on the Proposed design, shouldn't it be the same for the Baseline to give a more accurate energy savings? So this is where 90.1 also mentions that when rotating the Baseline model 0,90,180,270 rotations, that it doesn't project shade onto itself. Again this would have been considered during selection of your orginal site layout. In short, if a shading model can be generated to support permanent shading cast upon the Proposed building surfaces, they should be modeled to reflect realistic energy savings against a non-shaded Basecase. If the shadow is not cast on that room for the entire day for all 365days then do not model with shading. At this time, I don't see a way to model shading with a schedule (Trace700). The Trace7000 "Terrain" is only a modifier of windspeed used in the Outside Film calculation.

Be Sustainable -- Never let today use up tomorrow!.

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Joined: 2010-10-01
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