[Bldg-sim] Design Builder : Low E coated surface

[D. Charlie Curcija]

WINDOW has function to flip glass.  It is a check box "flip" at the 
glazing layer level.  Same function is available in DesignBuilder.

DesignBuilder includes IGDB and the rule is the same as in WINDOW, 
surface 1 is facing outdoor, while surface 2 is facing indoors.  Same 
rule applies to layers, first glass is outdoormost, last glass is 
innermost.  In DesignBuiolder you can look at the emissivities of each 
glass layer and if emissivity is lower than 0.84 (usually low-e is is 
less that about 0.2), then this is low-e surface.  So if the glass that 
you selected has low-e surface facing wrong side, then you can check 
"flip" box and reverse it.  As somebody pointed out, this reverses the 
orientation of the glass, not the order of glass in the glazing system.  
Typically, you want to have one low-e surface in each gap space (having 
two low-e surfaces in the same gap space provides negligible 
improvement) and typically you do not want low-e facing either indoor or 
outdoor (some manufacturers have started using hard coat low-e facing 
indoors in order to improve U-factor of the glazing system and whole 
window, but this is still pretty rare due to issues of cleaning exposed 
low-e surfaces, discoloring, etc.  Also, it has negative consequences on 
condensation resistance.)  Thus if you have, for example double glazing 
system with Pilkington Suncool  Brilliant 30/17 (low-e glass) on the 
outdoor side and Pilkington North America Optifloat  Clear (Clear) on 
the indoor side, you will notice that the low-e surface on the 
Pilkington Suncool  Brilliant 30/17 is surface #1, which would mean that 
it faces outdoors.  So you would check flip box, which will place low-e 
coating on surface #2, which would be correct becasue it would be facing 
the glazing gap.

Charlie Curcija
DesignBuilder Software USA

-------- Original Message --------
Subject: Re: [Bldg-sim] Design Builder : Low E coated surface
From: Chris Yates <chris at zed-uk.com>
To: Nick Kovess <Nick.Kovess at meinhardtgroup.com>
Date: 8/28/2009 5:17 AM
> Nick's right. I didn't have the software in front of me at the time. 
> Window 5 uses the international glazing database that I talked about. 
> DB uses the same data. It is easier to review it in Window. I don't 
> think Window has a flip feature - is that right Nick?
> Cheers
> Chris
>
> Sent from my iPhone
>
> On 28 Aug 2009, at 06:48, "Nick Kovess" 
> <Nick.Kovess at meinhardtgroup.com> wrote:
>
>> Hi Deepa,
>>
>> I believe 'flip' means to switch which 'surface' on the individual 
>> pane the low-E coating is applied to. The order of the panes in the 
>> glazing setup will not change if you tick the flip box. When you are 
>> building up a glazing system, design builder clearly shows 'outermost 
>> pane' and 'innermost pane', these do not change if you check the flip 
>> box.
>>
>> Basically I believe it is the opposite to what Chris just said.
>>
>> In terms of finding out on which surface the coating originally is, 
>> and thus where it will move to if 'flipped', I have found using the 
>> software Window5 easiest for this. In Window5, find the same pane you 
>> wish to use in DesignBuilder and when you look at the glazing set up 
>> you can see a dashed line which indicates the location of the coating.
>>
>> Hope that helps
>>
>>
>>
>> Nick Kovess
>> Engineer | Building Science Group
>>
>> Meinhardt
>> Level 12
>> 501 Swanston Street
>> Melbourne VIC 3000
>> Phone: +61 (0) 3 8676 1200
>> Direct:  +61 (0) 3 8676 1366
>> Mobile: 0413 586 936
>> Fax:     +61 (0) 3 8676 1201
>> E-mail: nick.kovess at meinhardtgroup.com
>> http://www.meinhardtgroup.com
>>
>>
>>>>> Chris Yates <chris at zed-uk.com> 28/08/2009 3:14 pm >>>
>> Hi Deepa
>> I think flip means swap the place of inside and outside pane - not
>> flipping the individual panes so that the coating moves to the
>> opposite surface.
>> DB uses the International Glazing Database which you can download from
>> lbnl. It's easy to use so worth downloading a copy. Unforunately you
>> can't transfer the results to DB at present.
>>
>> Chris
>>
>> Sent from my iPhone
>>
>> On 28 Aug 2009, at 04:38, deepa chandrashekaran 
>> <creations.deepa at googlemail.com
>>> wrote:
>>
>>> Jeff,
>>>
>>> Thank you for responding. I agree that it depends on the climate.
>>>
>>> Design Builder has the option called 'flip' while making the double
>>> pane assembly. Hence I was not clear as to which surface is the
>>> coating on and what does flip actually mean?
>>>
>>>
>>> Deepa
>>>
>>>
>>> On Thu, Aug 27, 2009 at 8:26 PM, Jeff Haberl <jhaberl at tamu.edu> wrote:
>>> The "surface" depends on the climate.
>>>
>>> Cooling dominated climates benefit from the low-E on the inside
>>> surface of the outside pane.
>>>
>>> Heating dominated climates benefit from the low-E on the outside
>>> surface of the inside pane.
>>>
>>> Such characteristics are normally defined by the applicable codes
>>> for a given location.
>>>
>>> Jeff
>>> BB 8=! 8=) :=) 8=) ;=) 8=) 8=( 8=) :=') 8=) 8=) 8=? BB
>>>
>>> Jeff S. Haberl, Ph.D., P.E., 
>>> FASHRAE...................jhaberl at esl.tamu.edu
>>>
>>> Professor.
>>> .....................................................Office Ph: 
>>> 979-845-6507
>>>
>>> Department of Architecture.......................Lab Ph: 979-845-6065
>>>
>>> Energy Systems Laboratory.......................FAX: 979-862-2457
>>>
>>> Texas A&M University..............................77843-3581
>>>
>>> College Station, Texas, USA.......................URL: www-
>>> esl.tamu.edu
>>>
>>> BB 8=/ 8=) :=) 8=) ;=) 8=) 8=() 8=) 8=?  8=) 8=) 8= BB
>>>
>>> From: bldg-sim-bounces at lists.onebuilding.org 
>>> <bldg-sim-bounces at lists.onebuilding.org
>>>>
>>> To: Bldg-Sim <bldg-sim at lists.onebuilding.org>
>>> Sent: Thu Aug 27 21:58:12 2009
>>> Subject: [Bldg-sim] Design Builder : Low E coated surface
>>> Hello all,
>>>
>>> I am trying to model several types of Low E glazing in Design
>>> Builder to understand the effect on the peak heating and cooling load.
>>>
>>> While choosing different glazing, I could not understand which
>>> surface of the glazing has the Low E coating.
>>>
>>> I would appreciate any inputs about this aspect.
>>>
>>>
>>> Thanks,
>>> Deepa Chandrashekaran, LEED AP
>>> Master of Building Science 2010
>>> University of Southern California
>>>
>>>
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>>
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