[Equest-users] Ground/Water reflectance

[Alex Krickx]

Thanks Bill and John for your responses.

I guess I would expect that the ocean would be a bit more "turbid" (seems appropriate) - but what about for buildings facing a lake or harbor where the water is calmer? Perhaps the additional reflected solar gain is negligible, but my gut tells me that is not the case.

This project is a retrofit and they talked of having intense heat along the facades facing the water. Perhaps it's more due to the tinted single-pane glass that gets hot (?) but my initial thought was the water is the culprit.

Is it possible to create a 2d shape in the ground plane south of the building, and apply the reflectance to that, or do I need to apply it to the whole ground?

I looked through a previous project and didn't see the term "GND-REFLECTANCE" anywhere in the inp or pd2 files. Is the default to have a ground-reflectance of 0? If so, I guess I'll run one case with 0, and one with 0.05... although I doubt there will be much difference between the two.

Thanks again - any other thoughts on this are much appreciated.

Kind regards,
Alex Krickx


Alex Krickx
Building Energy Specialist
[cid:image004.jpg at 01CB95F8.55501210]
1250 Elko Dr, Sunnyvale, CA 94089
(t) 408.541.8124

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From: Bishop, Bill [mailto:wbishop at pathfinder-ea.com]
Sent: Tuesday, December 07, 2010 7:20 AM
To: John Aulbach; Alex Krickx; equest-users at lists.onebuilding.org
Subject: RE: [Equest-users] Ground/Water reflectance

Alex,

Exterior surfaces have a "Ground reflectance" property - GND-REFLECTANCE, accessible through the Daylighting - Shading - Other tab of the exterior surface. Reading the DOE-2 Help description, the reflectance value for "ocean" is 0.05, implying that most solar radiation is absorbed, not reflected. I'm guessing that the visual glare we perceive does not increase the solar load as much as we would think. Sea monsters do not seem to have been considered by the DOE-2 team.

Regards,
Bill

William Bishop, PE, BEMP, LEED(r) AP | Pathfinder Engineers & Architects LLP
Mechanical Engineer

[cid:image003.jpg at 01CB95F8.55501210]134 South Fitzhugh Street             Rochester, NY 14608
T: (585) 325-6004 Ext. 114            F: (585) 325-6005
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________________________________
From: equest-users-bounces at lists.onebuilding.org [mailto:equest-users-bounces at lists.onebuilding.org] On Behalf Of John Aulbach
Sent: Monday, December 06, 2010 8:35 PM
To: Alex Krickx; equest-users at lists.onebuilding.org
Subject: Re: [Equest-users] Ground/Water reflectance


Alex:



I wonder if the turbidity (word ??) of the water will actually not make a difference. Any harbor will have boats, wind effects, and an occasional sea monster disturbing the "glass" water.



Only in paintings ???


John R. Aulbach, PE, CEM
Senior Energy Engineer
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Partner Energy
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W: 888-826-1216, X254| D: 310-765-7295 | F: 310-817-2745
www.ptrenergy.com<http://www.ptrenergy.com/> | jaulbach at ptrenergy.com<mailto:%7C%20jaulbach at ptrenergy.com>



________________________________
From: Alex Krickx <akrickx at seriousmaterials.com>
To: "equest-users at lists.onebuilding.org" <equest-users at lists.onebuilding.org>
Sent: Mon, December 6, 2010 5:11:24 PM
Subject: [Equest-users] Ground/Water reflectance
Hello everyone,

I've got a building that is located at the edge of a harbor with the water directly to the south of it. How do I model a reflective surface on the ground that represents the harbor? I feel this is key to include, as this reflectivity will send additional heat through the windows. I looked through the archives but didn't see anything related to ground reflectivity.

If anyone knows how to create reflective objects and/or an appropriate value of reflectivity for water in eQUEST, that would be most helpful.

Thanks in advance!

Regards,
Alex Krickx


Alex Krickx
Building Energy Specialist
[cid:image004.jpg at 01CB95F8.55501210]
1250 Elko Dr, Sunnyvale, CA 94089
(t) 408.541.8124

Warning: The information contained in this e-mail may be privileged attorney-client communications or attorney work product and/or proprietary and confidential.  If the reader of this message is not the intended recipient then you have received it in error and any review, distribution or copying of this message is prohibited and you are to notify us immediately by reply e-mail and delete the original message immediately.



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