Exterior Air Film - glazing

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Nick,
Would you not agree that one should define the glazing Conductance in the eQuest input, not the glazing U-value? That way the .sim file reported glazing U-value is closer to what is expected?

Christopher Jones, P.Eng.
Tel: 416.644.4226 ? Toll Free: 1.888.425.7255 x 527

Chris Jones
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No problem Nick. I?ve been reading those manuals for some 20 odd years and I still find things I didn?t know about.

Christopher Jones, P.Eng.
Tel: 416.644.4226 ? Toll Free: 1.888.425.7255 x 527

Chris Jones
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Chris:

After backtracking to the old glossary? I?ve learned something today! You
are absolutely right, and thank you for pressing the point!

I had the mistaken impression the U-values prescribed by 90.1 were
exclusive of air films, analogous to GLASS-CONDUCTANCE. The LV-D reports,
inclusive of the exterior air film (assuming a 7.5mph wind), actually ought
match the prescribed gross assembly U-factor. I?ll be updating some of my
personal resources!

For anyone else interested, here shared are coefficients for a curve
matching the DOE2 reference for converting between the two:

Omar, I?ll leave it to you to decide how to proceed. I have (successfully
enough) addressed the exact same commentary multiple times by simply
illustrating my inputs matched the prescribed values. My heart was in the
right place, but I (and perhaps my reviewers) did not realize the
disconnect with the output reports was not simply a matter of an erroneous
inclusion of air films. I will be changing my ways moving forward,
personally!

Kind regards, and happy holidays to everyone on the list!

~Nick

*NICK CATON, P.E.*
*Owner*

*Caton Energy Consulting*
1150 N. 192nd St., #4-202

Shoreline, WA 98133
office: 785.410.3317

www.catonenergy.com

*From:* Jones, Christopher [mailto:cjones at halsall.com]
*Sent:* Tuesday, December 23, 2014 5:33 AM
*To:* Nicholas Caton; Omar ElRawy; equest
*Subject:* RE: [Equest-users] Exterior Air Film - glazing

Nick,

Would you not agree that one should define the glazing Conductance in the
eQuest input, not the glazing U-value? That way the .sim file reported
glazing U-value is closer to what is expected?

*Christopher Jones**,* P.Eng.
Tel: 416.644.4226 ? Toll Free: 1.888.425.7255 x 527

*From:* Nicholas Caton [mailto:ncaton at catonenergy.com
]
*Sent:* Monday, December 22, 2014 4:46 PM
*To:* Jones, Christopher; Omar ElRawy; equest
*Subject:* RE: [Equest-users] Exterior Air Film

The LV-D reports (and others touching on windows/constructions) do indeed
include an exterior air film. I don?t know of a way to change that.

A quick screengrab of your (correct) inputs and a one-line explanation of
that fact is probably your most expedient path forward for a LEED review
response.

~Nick

*NICK CATON, P.E.*
*Owner*

*Caton Energy Consulting*
1150 N. 192nd St., #4-202

Shoreline, WA 98133
office: 785.410.3317

www.catonenergy.com

*From:* Equest-users [mailto:equest-users-bounces at lists.onebuilding.org] *On
Behalf Of *Jones, Christopher
*Sent:* Monday, December 22, 2014 8:23 AM
*To:* Omar ElRawy; equest
*Subject:* Re: [Equest-users] Exterior Air Film

For glazing, you have to enter the GLASS-CONDUCTANCE into eQuest, not the
glazing U-value. See page 65 in the DOE22Vol2-Dictionary reference manual
available for download at doe2.com.

*Christopher Jones**,* P.Eng.
Tel: 416.644.4226 ? Toll Free: 1.888.425.7255 x 527

*From:* Equest-users [mailto:equest-users-bounces at lists.onebuilding.org
] *On Behalf Of *Omar ElRawy
*Sent:* Monday, December 22, 2014 7:28 AM
*To:* equest
*Subject:* [Equest-users] Exterior Air Film

Dear all,

I have a problem reporting baseline case for LEED submission,
where the exterior walls and windows U-values in Report LV-D appears less
than the ASHRAE G 90.1 values that I did enter to the model, and this is
(as I think) because eQuest adds the exterior air-film effect to the
assembly during the run.

My question is that; can I disable this eQuest calculation to see my input
directly in LV-D report or not?

Thanks,

*Omar ElRawy*,
*LEED AP BD+C*LEED Project Manager
EA Sustainable Building Consultants
http://www.ea-buildingconsultants.com/

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Chris, Thanks so much for making this very clear.
Nick, Thanks for sharing the coefficients, I think I will go on the safe side and present an LV-D report with the actual intended values, this won't take much effort using the coefficients I guess.
Thanks 'nHappy Holidays for All

Best Regards,
Omar ElRawy, LEED AP BD+C
LEED Project Manager
EA Sustainable Building Consultants
http://www.ea-buildingconsultants.com/

Omar ElRawy, LEED AP BD+C LEED Project Manager, EA Sustainable Building Consultants www.ea-buildingconsultants.com
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Here?s a dumb question:

How do you input the glass conductance if you aren?t modeling your glass as a simplified assembly? I am used to either using the glass library or a LBNL Window input. I?ve always assumed (perhaps incorrectly?) that if you use the simplified (Shading Coefficient) method to specify glass, you get incorrect solar heat gain numbers in your calcs.

Vikram Sami
BEMP, LEED BD+C
Associate Partner

ZGF ARCHITECTS LLP
T 206.521.3509 E vikram.sami at zgf.com
925 Fourth Avenue, Suite 2400
Seattle, WA 98104

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Hi Vikram,

?Incorrect? may be a strong term here ? I?d suggest ?Less Correct? =).

To my best understanding, simulating using the LBNL WINDOW and glass
library approaches essentially means you additionally account for the
hourly performance with respect to solar angle. As 90.1 merely prescribes
whole assembly properties, exclusive of angular performance, it?s my best
understanding that you may choose any of these approaches as best fits the
needs of your project at-hand (though one should be uniform in which
approach they apply to the baseline and proposed models).

As to ?how? conductance is entered, my understanding is that when you use
the glass library (or specify a GLASS-TYPE-CODE), conductive properties are
already worked into the associated library entry and you do not need to
concern yourself with the GLASS-CONDUCTANCE input.

Regards,

~Nick

*NICK CATON, P.E.*
*Owner*

*Caton Energy Consulting*
1150 N. 192nd St., #4-202

Shoreline, WA 98133
office: 785.410.3317

www.catonenergy.com

*From:* Sami, Vikram [mailto:vikram.sami at zgf.com]
*Sent:* Saturday, December 27, 2014 2:06 PM
*To:* Nicholas Caton; Jones, Christopher; Omar ElRawy; equest
*Subject:* RE: [Equest-users] Exterior Air Film - glazing

Here?s a dumb question:

How do you input the glass conductance if you aren?t modeling your glass as
a simplified assembly? I am used to either using the glass library or a
LBNL Window input. I?ve always assumed (perhaps incorrectly?) that if you
use the simplified (Shading Coefficient) method to specify glass, you get
incorrect solar heat gain numbers in your calcs.

*Vikram Sami*
BEMP, LEED BD+C
Associate Partner

ZGF ARCHITECTS LLP
*T *206.521.3509 *E *vikram.sami at zgf.com
925 Fourth Avenue, Suite 2400
Seattle, WA 98104

*From:* Equest-users [mailto:equest-users-bounces at lists.onebuilding.org
] *On Behalf Of *Nicholas Caton
*Sent:* Tuesday, December 23, 2014 1:43 PM
*To:* Jones, Christopher; Omar ElRawy; equest
*Subject:* Re: [Equest-users] Exterior Air Film - glazing

Chris:

After backtracking to the old glossary? I?ve learned something today! You
are absolutely right, and thank you for pressing the point!

I had the mistaken impression the U-values prescribed by 90.1 were
exclusive of air films, analogous to GLASS-CONDUCTANCE. The LV-D reports,
inclusive of the exterior air film (assuming a 7.5mph wind), actually ought
match the prescribed gross assembly U-factor. I?ll be updating some of my
personal resources!

For anyone else interested, here shared are coefficients for a curve
matching the DOE2 reference for converting between the two:

Omar, I?ll leave it to you to decide how to proceed. I have (successfully
enough) addressed the exact same commentary multiple times by simply
illustrating my inputs matched the prescribed values. My heart was in the
right place, but I (and perhaps my reviewers) did not realize the
disconnect with the output reports was not simply a matter of an erroneous
inclusion of air films. I will be changing my ways moving forward,
personally!

Kind regards, and happy holidays to everyone on the list!

~Nick

*NICK CATON, P.E.*
*Owner*

*Caton Energy Consulting*
1150 N. 192nd St., #4-202

Shoreline, WA 98133
office: 785.410.3317

www.catonenergy.com

*From:* Jones, Christopher [mailto:cjones at halsall.com]
*Sent:* Tuesday, December 23, 2014 5:33 AM
*To:* Nicholas Caton; Omar ElRawy; equest
*Subject:* RE: [Equest-users] Exterior Air Film - glazing

Nick,

Would you not agree that one should define the glazing Conductance in the
eQuest input, not the glazing U-value? That way the .sim file reported
glazing U-value is closer to what is expected?

*Christopher Jones**,* P.Eng.
Tel: 416.644.4226 ? Toll Free: 1.888.425.7255 x 527

*From:* Nicholas Caton [mailto:ncaton at catonenergy.com
]
*Sent:* Monday, December 22, 2014 4:46 PM
*To:* Jones, Christopher; Omar ElRawy; equest
*Subject:* RE: [Equest-users] Exterior Air Film

The LV-D reports (and others touching on windows/constructions) do indeed
include an exterior air film. I don?t know of a way to change that.

A quick screengrab of your (correct) inputs and a one-line explanation of
that fact is probably your most expedient path forward for a LEED review
response.

~Nick

*NICK CATON, P.E.*
*Owner*

*Caton Energy Consulting*
1150 N. 192nd St., #4-202

Shoreline, WA 98133
office: 785.410.3317

www.catonenergy.com

*From:* Equest-users [mailto:equest-users-bounces at lists.onebuilding.org] *On
Behalf Of *Jones, Christopher
*Sent:* Monday, December 22, 2014 8:23 AM
*To:* Omar ElRawy; equest
*Subject:* Re: [Equest-users] Exterior Air Film

For glazing, you have to enter the GLASS-CONDUCTANCE into eQuest, not the
glazing U-value. See page 65 in the DOE22Vol2-Dictionary reference manual
available for download at doe2.com.

*Christopher Jones**,* P.Eng.
Tel: 416.644.4226 ? Toll Free: 1.888.425.7255 x 527

*From:* Equest-users [mailto:equest-users-bounces at lists.onebuilding.org
] *On Behalf Of *Omar ElRawy
*Sent:* Monday, December 22, 2014 7:28 AM
*To:* equest
*Subject:* [Equest-users] Exterior Air Film

Dear all,

I have a problem reporting baseline case for LEED submission,
where the exterior walls and windows U-values in Report LV-D appears less
than the ASHRAE G 90.1 values that I did enter to the model, and this is
(as I think) because eQuest adds the exterior air-film effect to the
assembly during the run.

My question is that; can I disable this eQuest calculation to see my input
directly in LV-D report or not?

Thanks,

*Omar ElRawy*,
*LEED AP BD+C*LEED Project Manager
EA Sustainable Building Consultants
http://www.ea-buildingconsultants.com/

______________________________________________________________________
NOTICE: This communication and any attachments ("this message") may contain
confidential information for the sole use of the intended recipient(s). Any
unauthorized use, disclosure, viewing, copying, alteration, dissemination
or distribution of, or reliance on this message is strictly prohibited. If
you have received this message in error, or you are not an authorized
recipient, please notify the sender immediately by replying to this
message, delete this message and all copies from your e-mail system and
destroy any printed copies.

______________________________________________________________________
NOTICE: This communication and any attachments ("this message") may contain
confidential information for the sole use of the intended recipient(s). Any
unauthorized use, disclosure, viewing, copying, alteration, dissemination
or distribution of, or reliance on this message is strictly prohibited. If
you have received this message in error, or you are not an authorized
recipient, please notify the sender immediately by replying to this
message, delete this message and all copies from your e-mail system and
destroy any printed copies.

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