[Equest-users] Spandrel Glass
Bishop, Bill
bbishop at pathfinder-ea.com
Mon Dec 10 07:11:16 PST 2018
Paul,
I think you’re getting hung-up on curtain wall = windows. If the spandrel sections are opaque (and it sounds like they are since they have a painted interior lite), then they function more like walls in an energy model than windows. (The model doesn’t care if they’re load-bearing.) You could model the curtain wall areas (the non-brick areas in your project rendering) as exterior walls with spandrel construction, then create and assign windows to the spandrel walls. This would also allow you to model the setback of the curtain wall by adjusting the coordinates of the wall so that the spandrel + window sections can be shown recessed in the eQUEST 3-D view. (You can give windows a SETBACK but the windows won’t be shown recessed in the 3-D view.) However, if you adjust the spandrel wall location, the non-brick areas will be recessed. Then you assign a light-blue color to the spandrel construction, a red color for the brick construction, and something different for the windows, to get a good 3-D rendering.
Modeling the spandrel areas as walls will also give you more accurate reporting from the modeling output (DOE-2 reports; sim file) for your window-to-wall ratio or % fenestration.
~Bill
William Bishop, PE, BEMP, BEAP, CEM, LEED AP
Senior Energy Engineer
[Pathfinder-EA-logo-2]T: (585) 698-1956 F: (585) 325-6005
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From: Equest-users <equest-users-bounces at lists.onebuilding.org> On Behalf Of Paul Diglio via Equest-users
Sent: Monday, December 10, 2018 8:50 AM
To: Daniel Knapp <danielk at arborus.ca>
Cc: equest-users at onebuilding.org
Subject: Re: [Equest-users] Spandrel Glass
Dan:
Thanks for the information. Averaging the spandrel U-factor with the exterior wall is a great idea. Unfortunately, on this project many of the spandrels are part of the curtain wall and there is no exterior wall.
Regards,
Paul Diglio
87 Fairmont Avenue
New Haven, CT 06513
________________________________
From: Daniel Knapp <danielk at arborus.ca<mailto:danielk at arborus.ca>>
To: Paul Diglio <paul.diglio at sbcglobal.net<mailto:paul.diglio at sbcglobal.net>>
Cc: "equest-users at onebuilding.org<mailto:equest-users at onebuilding.org>" <equest-users at onebuilding.org<mailto:equest-users at onebuilding.org>>
Sent: Sunday, December 9, 2018 12:58 PM
Subject: Re: [Equest-users] Spandrel Glass
I have been greatly interested to read everyone’s comments on how they are modelling spandrel panels. It seems to me that there are many valid approaches which get us to a similar place in the end.
Generally, I have found it convenient to model spandrel panels as a separate glass type which can be defined by the simplified method of using a U-value and a SHGC of 0. This makes it easy to assign the correct area in the wizard, and this area can then be modified in Detailed Edit by adjusting window height/width, etc. It also makes it easy to parametrize the spandrel panels and model a range of U-values, including the 90.1 reference U-value which is taken from a light-weight wall construction for the correct climate zone. Given that spandrel panels are generally constructed of glass, metal, and insulation I think the simplified approach is appropriate, since the construction will have a very low heat capacity and heat transfer will be on time scales shorter than 1 hour. We tend to build a lot of models for parametric analysis, and this approach makes it easy to adjust spandrel sizes and thermal performance. It’s much harder to adjust two different exterior wall types and change their relative areas post-wizard, although Nick appears to have come up with a very clever approach to automating this process by adjusting his plenum heights.
Another approach I have taken is to calculate the relative area of the spandrel panels and the opaque wall and use an average U-value for the exterior wall. This approach tends to work best when the spandrel is somewhat uniformly distributed across the wall. Since the indoor air is assumed to be uniformly mixed in any given zone in DOE-2 it doesn’t matter whether you localize the heat loss to a spandrel panel or allow it to spread across the whole wall area.
Anyway, just wanted to put in my two cents.
Have a great weekend everyone!
Dan
—
Daniel Knapp, PhD, PPhys, BEMP, LEED AP
Senior Energy Analyst
ARBORUS CONSULTING
43 Eccles St. 2nd Floor,
Ottawa, ON K1R 6S3
(613) 234-7178 x113
danielk at arborus.ca<mailto:robinh at arborus.ca>
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From: Equest-users <equest-users-bounces at lists.onebuilding.org<mailto:equest-users-bounces at lists.onebuilding.org>> on behalf of Paul Diglio via Equest-users <equest-users at lists.onebuilding.org<mailto:equest-users at lists.onebuilding.org>>
Reply-To: Paul Diglio <paul.diglio at sbcglobal.net<mailto:paul.diglio at sbcglobal.net>>
Date: Saturday, December 8, 2018 at 6:55 PM
To: David Eldridge <DEldridge at grummanbutkus.com<mailto:DEldridge at grummanbutkus.com>>
Cc: "equest-users at onebuilding.org<mailto:equest-users at onebuilding.org>" <equest-users at onebuilding.org<mailto:equest-users at onebuilding.org>>, David Griffin II <DGriffin at archnexus.com<mailto:DGriffin at archnexus.com>>
Subject: Re: [Equest-users] Spandrel Glass
HI David:
Please find attached a rendering of the building I am modeling. Note there are two types of exterior walls, the brick covered columns and sills and the rest is ACM. You can see the spandrel panels under and above some of the windows in a sort of grey-blue color. The spandrels total about 7,000 square feet and the windows about 30,000 square feet. There is some screening on the ends of the building which may or may not be eliminated.
I was able to model the two exterior wall types and added the spandrels as a different glass type. Yes, the spandrel consists of an exterior clear lite, air gap, painted interior lite and 6" of blown-in foam between that and the conditioned space. It actually has a better U-factor than the ACM walls.
Thank you,
Paul Diglio
87 Fairmont Avenue
New Haven, CT 06513
________________________________
From: David Eldridge <DEldridge at grummanbutkus.com<mailto:DEldridge at grummanbutkus.com>>
To: Paul Diglio <paul.diglio at sbcglobal.net<mailto:paul.diglio at sbcglobal.net>>
Cc: David Griffin II <DGriffin at archnexus.com<mailto:DGriffin at archnexus.com>>; Nicholas Caton <Nicholas.Caton at schneider-electric.com<mailto:Nicholas.Caton at schneider-electric.com>>; "jra_sac at yahoo.com<mailto:jra_sac at yahoo.com>" <jra_sac at yahoo.com<mailto:jra_sac at yahoo.com>>; "equest-users at onebuilding.org<mailto:equest-users at onebuilding.org>" <equest-users at onebuilding.org<mailto:equest-users at onebuilding.org>>
Sent: Saturday, December 8, 2018 1:42 PM
Subject: Re: [Equest-users] Spandrel Glass
Some of the mixup might be that some walls are for sake of argument in round figures 50% spandex and 50% vision glass, and some minor percent structure and other.
Other buildings might 33% structure/masonry/etc and 33% spandrel, and 33% vision glazing.
So a common approach in case a is spandrel = wall, windows are windows.
For case B you need two different walls, plus windows in one or both, and how you model the two walls may be important to your zone loads, but look odd in the rendering even if it is thermally equivalent and geometrically expedient.
If you have a photo of the facade you are talking about it might help to sync all of us.
DSE Mobile
On Dec 8, 2018, at 10:40 AM, Paul Diglio <paul.diglio at sbcglobal.net<mailto:paul.diglio at sbcglobal.net>> wrote:
I'd like to thank every for their comments. I don't understand how the spandrels can be modeled as exterior walls since the exterior walls have a different u-factor and eQuest does not allow me to draw an exterior wall over an existing. I think I understand Nick's approach, but it seems that the spandrels are not placed in the appropriate location and will influence the angle of solar gain?
To further complicate matters, this 5 story building does not have a plenum ceiling, the floor deck above is visible in the space below.
I was able to successfully model the spandrels by using a different type of glass, then entering the U-factor by the simplified method and zeroing the Sc and reflectance. The problem is that LV-D reports the spandrels as part of the glass, so it throws the window to wall ration calculations off.
I found the simplest method was simply remove the spandrels (+100) and run the LV-D report to get the actual area of the vision glass.
Regards,
Paul Diglio
87 Fairmont Avenue
New Haven, CT 06513
203-415-0082
________________________________
From: David Griffin II <DGriffin at archnexus.com<mailto:DGriffin at archnexus.com>>
To: Nicholas Caton <Nicholas.Caton at schneider-electric.com<mailto:Nicholas.Caton at schneider-electric.com>>; David Eldridge <DEldridge at grummanbutkus.com<mailto:DEldridge at grummanbutkus.com>>; "jra_sac at yahoo.com<mailto:jra_sac at yahoo.com>" <jra_sac at yahoo.com<mailto:jra_sac at yahoo.com>>; Paul Diglio <paul.diglio at sbcglobal.net<mailto:paul.diglio at sbcglobal.net>>; "equest-users at onebuilding.org<mailto:equest-users at onebuilding.org>" <equest-users at onebuilding.org<mailto:equest-users at onebuilding.org>>
Sent: Friday, December 7, 2018 5:18 PM
Subject: RE: [Equest-users] Spandrel Glass
I second Nick’s approach to spandrel. I have not thought to use the plenum as a geometry generator. I’ll have to utilize that next time.
By code, spandrel is considered a wall construction that happens to have glass in it rather than a window you can’t see through. In my mind, that justifies using a wall construction and adjusting the exterior surface reflectance accordingly rather than try and model it as a window.
I hope everyone is having a great holiday season!
<http://www.archnexus.com/>
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DAVID W. GRIFFIN II<http://www.archnexus.com/>
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From: Nicholas Caton [mailto:Nicholas.Caton at schneider-electric.com]
Sent: Thursday, December 6, 2018 7:09 PM
To: David Eldridge <DEldridge at grummanbutkus.com>; jra_sac at yahoo.com; Paul Diglio <paul.diglio at sbcglobal.net>; equest-users at onebuilding.org
Subject: Re: [Equest-users] Spandrel Glass<http://www.archnexus.com/>
<http://www.archnexus.com/>
I’ll toss some extra thoughts/experience into the pile:<http://www.archnexus.com/>
<http://www.archnexus.com/>
My preferred approach to handling large amounts of spandrel glass is to start by taking advantage of the wizards’ capacity to generate separate “plenum” exterior wall sections (of height resulting from your ceiling inputs), to produce equivalent area to the spandrel glass on each orientation. Those separate sections are in part a by-product of the intent to distinguish the conditioned space/zone volume relative to the floor-to-floor height, but we can repurpose them!<http://www.archnexus.com/>
<http://www.archnexus.com/>
I do not create glass on those “plenums” wall sections, but rather just make a new “spandrel” exterior wall construction in detailed mode and use custom user default expressions to automate assigning “spandrel” vs. “normal” constructions to each exterior surface as a function of their Z coordinate (0 = normal wall, else spandrel construction).<http://www.archnexus.com/>
<http://www.archnexus.com/>
This can be combined with post-wizard manipulation of interior space/ceiling heights (which do not have to line up with the “seams” separating plenum from normal walls), to capture cases where the spandrel actually extends below the ceiling line and ensure the conditioned volume is accurate around your perimeters. Be mindful that if the spandrel glass is largely incident on the conditioned volume it may be more appropriate to move them off the plenum spaces and onto the occupied spaces. <http://www.archnexus.com/>
<http://www.archnexus.com/>
There is an aesthetic “downside” to this approach to consider (according to some industry professionals I’ve worked with), but if someone *really* wants a pretty 3D model picture that looks like a fishbowl from the likes of eQuest (?), I’ll just add that you can generate some (apparently convincing) “forgery” of extra windows by mis-using MSPAINT – the duct tape of my graphical tool belt. And yes, I sleep at night just fine, thank you.<http://www.archnexus.com/>
<http://www.archnexus.com/>
@David: I’m not sure about that library entry either, but I have in the past been convinced myself it was okay to use the simplified window glass definition option and <http://www.archnexus.com/>
* specify a shading coefficient of zero (where SC is the ratio of solar energy transmitted relative to single pane float glass), and<http://www.archnexus.com/>
* specify a U-value appropriate to the degree of insulation (though I’d leave this equivalent to the underlying glass layer(s) if it’s just painted panels – run into that a couple times). <http://www.archnexus.com/>
This modeling approach doesn’t pick up on all of the actual nuances of radiative* emissivity for painted-over windows, but it has for me been good enough for (literally) government work where there were much bigger problems to focus the energy model’s development around… If anyone has developed further best practices for handling “high-e coatings” applied to mitigating unwanted transmissive solar gains, I am certainly all ears =).<http://www.archnexus.com/>
<http://www.archnexus.com/>
~Nick<http://www.archnexus.com/>
<http://www.archnexus.com/>
<http://www.archnexus.com/>
<image001.png><http://www.archnexus.com/>
Nick Caton, P.E., BEMP<http://www.archnexus.com/>
Senior Energy Engineer
Regional Energy Engineering Manager<http://www.archnexus.com/>
Energy and Sustainability Services
Schneider Electric<http://www.archnexus.com/>
D 913.564.6361
M 785.410.3317
F 913.564.6380
E nicholas.caton at schneider-electric.com<http://www.archnexus.com/>
15200 Santa Fe Trail Drive
Suite 204
Lenexa, KS 66219
United States<http://www.archnexus.com/>
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From: Equest-users <equest-users-bounces at lists.onebuilding.org> On Behalf Of David Eldridge via Equest-users
Sent: Wednesday, December 05, 2018 5:59 PM
To: jra_sac at yahoo.com; Paul Diglio <paul.diglio at sbcglobal.net>; equest-users at onebuilding.org
Subject: Re: [Equest-users] Spandrel Glass<http://www.archnexus.com/>
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[External email: Use caution with links and attachments]<http://www.archnexus.com/>
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Paul – to answer your question: painfully? It may not be that bad actually – what’s your base wall type? For a curtain wall that is half spandrel and half vision glass, make the exterior opaque surface equivalent to the spandrel sections as a defined opaque wall construction, and then add the vision glass to that – if you change the surface constructions in spreadsheet view it may not be that painful after all. The painful part will be deleting all of the current spandrel sections that are now defined as the base wall.<http://www.archnexus.com/>
<http://www.archnexus.com/>
JRA – I’m not sure of the purpose of the spandrel glass type in the library, I don’t know if that window object model has the capability to perform as if it were an opaque surface although this spandrel glass definition may be available to be selected…I’m not sure it would be an accurate choice. I wonder if it is a research entry that isn’t meant for the modeling public. Anyone used it?<http://www.archnexus.com/>
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David<http://www.archnexus.com/>
<http://www.archnexus.com/>
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David S. Eldridge, Jr., P.E., LEED AP BD+C, BEMP, BEAP, HBDP<http://www.archnexus.com/>
Associate<http://www.archnexus.com/>
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From: Equest-users [mailto:equest-users-bounces at lists.onebuilding.org] On Behalf Of John Aulbach via Equest-users
Sent: Wednesday, December 05, 2018 5:39 PM
To: Paul Diglio <paul.diglio at sbcglobal.net>; Paul Diglio via Equest-users <equest-users at lists.onebuilding.org>; equest-users at onebuilding.org
Subject: Re: [Equest-users] Spandrel Glass<http://www.archnexus.com/>
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Paul,<http://www.archnexus.com/>
<http://www.archnexus.com/>
As I recall there IS a wall component called spandex glass in the Library. See if that solves your need.<http://www.archnexus.com/>
<http://www.archnexus.com/>
John<http://www.archnexus.com/>
Sent from Yahoo Mail on Android<http://www.archnexus.com/>
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On Wed, Dec 5, 2018 at 3:33 PM, Paul Diglio via Equest-users<http://www.archnexus.com/>
<equest-users at lists.onebuilding.org> wrote:<http://www.archnexus.com/>
I have a building with a very large amount of spandrel glass panels, which I modeled as glass since this seemed to be the only way to insert the panels into the exterior walls.<http://www.archnexus.com/>
<http://www.archnexus.com/>
I would somehow like to re-assign the spandrel panels as another exterior component so they will be counted as part of the exterior walls in the LV-D report instead of glass.<http://www.archnexus.com/>
<http://www.archnexus.com/>
Any idea on how this can be done?<http://www.archnexus.com/>
<http://www.archnexus.com/>
Thank you,<http://www.archnexus.com/>
<http://www.archnexus.com/>
Paul Diglio
87 Fairmont Avenue
New Haven, CT 06513 <http://www.archnexus.com/>
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