[Bldg-sim] "Opaque" windows
Liam O'Brien
obrien_liam at hotmail.com
Wed Feb 29 16:58:07 PST 2012
Strictly speaking, every construction (window or wall) has a non-zero SHGC. A portion of absorbed solar radiation will ultimately end up inside a space (via conduction through the surface and later radiation/convection into the space). A highly insulated wall will transmit a negligible amount of energy. The ASHRAE Handbook of Fundamentals (Fenestration chapter) provides a method for calculating the SHGC of window frames.
For your opaque windows, the transmittance may be zero, but the SHGC > 0. The magnitude will depend on the construction of the "window"; with higher U-values leading to a higher SHGC.
Why not use LBNL Window software to calculate it? I ran the following tests with opaque glass and clear glass. Here are the results:Plain opaque glass: SHGC = 0.31Opaque outside, air, Clear inside: SHGC = 0.16Clear outside, air, Opaque inside: SHGC = 0.5
Liam O'BrienAssistant ProfessorCarleton University
Date: Wed, 29 Feb 2012 19:11:02 -0500
From: energy.wwind at cox.net
To: bldg-sim at lists.onebuilding.org
Subject: Re: [Bldg-sim] "Opaque" windows
It depends which surface is black........ S1 (outside) clear
>>> normal reflected / transmitted fractions....etc.
On 2/29/2012 7:00 PM, Alex Krickx wrote:
Hi Robert,
If it's an opaque window, can't it be
described as a construction/wall material? Why still define it
as a window?
Alex Krickx
Alex Krickx, LEED AP
Building Energy
Specialist
Serious
Energy, Inc.
1250
Elko Dr, Sunnyvale, CA 94089
(t)
408.541.8124
akrickx at seriousenergy.com
The information
contained in this e-mail and any attachments may be
confidential, proprietary and/or privileged. If you are
not the intended recipient then you have received it in
error and any review, distribution or copying of this
message and any attachments is prohibited and you are to
notify the sender immediately by reply e-mail and delete
immediately this message and any attachments.
-----Original Message-----
From: bldg-sim-bounces at lists.onebuilding.org
[mailto:bldg-sim-bounces at lists.onebuilding.org] On Behalf Of
RobertWichert
Sent: Wednesday, February 29, 2012 3:59 PM
To: bldg-sim at lists.onebuilding.org; EnergyPro at yahoogroups.com;
energysoftllc
Subject: [Bldg-sim] "Opaque" windows
Does anybody know a SHGC for "Opaque"
windows? I think they painted
them black.
I don't think "0.00" is appropriate, but
I'm willing to listen to reason...
--
Robert Wichert P.Eng. LEED AP
+1 916 966 9060
FAX +1 916 966 9068
===============================================
_______________________________________________
Bldg-sim mailing list
http://lists.onebuilding.org/listinfo.cgi/bldg-sim-onebuilding.org
To unsubscribe from this mailing list
send a blank message to BLDG-SIM-UNSUBSCRIBE at ONEBUILDING.ORG
_______________________________________________
Bldg-sim mailing list
http://lists.onebuilding.org/listinfo.cgi/bldg-sim-onebuilding.org
To unsubscribe from this mailing list send a blank message to BLDG-SIM-UNSUBSCRIBE at ONEBUILDING.ORG
--
John R Ross III PE
Westwind Corporation
Vienna, VA 22182-1958
contact.wwind at cox.net
703-255-4712 Office
571-830-4596 Cell
_______________________________________________
Bldg-sim mailing list
http://lists.onebuilding.org/listinfo.cgi/bldg-sim-onebuilding.org
To unsubscribe from this mailing list send a blank message to BLDG-SIM-UNSUBSCRIBE at ONEBUILDING.ORG
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://lists.onebuilding.org/pipermail/bldg-sim-onebuilding.org/attachments/20120229/d054c1b7/attachment-0002.htm>
More information about the Bldg-sim
mailing list