[Equest-users] U-Value unexpected impact

[Robby Oylear]

Omar,

When looking at a problem like this, you should really look at how the
individual energy uses change, not just the total building energy use.

For example, if it's Space Cooling energy increased, then it's likely that
your worse U-factor glazing was acting as a way for heat to escape the
building from high internal loads.

This question becomes much simpler if you know where the energy is going in
your building.

-Robby

2011/10/13 Omar Osama <o_osama at live.com>

>  Thanks so much,
> I do appreciate your reply ,, I shall re-check internal loads, guess I have
> excessive lighting loads.
>
>
> *Omar AlRawi*
>
> *Project Engineer,*
>
> *EA Sustainable B uilding Consultants
> **www.ea-buildingconsultants.com*
>
> ------------------------------
>
>
> ------------------------------
> From: akrickx at seriousenergy.com
> To: chris at greenengineer.com; o_osama at live.com;
> equest-users at lists.onebuilding.org
> Date: Thu, 13 Oct 2011 10:39:02 -0700
> Subject: RE: [Equest-users] U-Value unexpected impact
>
>
>  Hi Omar,
>
> Another thing to check is that you are modeling a glass with a low-Solar
> Heat Gain Coefficient (SHGC). Low SHGC glasses and glass-units are best
> for situations where there is no need for passive heating (hot climates and
> internal load-dominated buildings).
>
> You can still maintain high VT (>0.5) with low SHGC (<0.3), so it doesn't
> need to sacrifice aesthetics and daylighting options.
>
> Great point on the internal loads Chris.
>
> Cheers,
> Alex
>
>
> Alex Krickx, LEED AP
>
> Building Energy Specialist
>
> Serious Energy, Inc.
>
> 1250 Elko Dr, Sunnyvale, CA 94089
>
> (t) 408.541.8124
>
> akrickx at seriousenergy.com
>
>
>
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>  ------------------------------
> *From:* equest-users-bounces at lists.onebuilding.org [
> equest-users-bounces at lists.onebuilding.org] On Behalf Of Christopher
> Schaffner [chris at greenengineer.com]
> *Sent:* Thursday, October 13, 2011 10:04 AM
> *To:* Omar Osama; equest-users at lists.onebuilding.org
> *Subject:* Re: [Equest-users] U-Value unexpected impact
>
>   In mild weather, with high internal heat gains, the losses through the
> glazing reduce the cooling load. In this situation, increasing the
> performance of the glass will cause increased energy consumption.
>
>  This counterintuitive result is often the result of an overestimation of
> internal heat gains.   You should perform a reality check on your internal
> heat gains, before you determine if this result is correct.
>
>  --
>
>  Chris Schaffner, PE
> LEED Fellow
> Founder and Principal
>
>  The Green Engineer, LLP
> Sustainable Design Consulting
> 50 Beharrell Street
> Concord, MA 01742
> T: 978.369.8978
> M:978.844.1464
> chris at greenengineer.com
> www.greenengineer.com
>
>  The Green Engineer, LLP is a Certified B Corporation
>
>   From: Omar Osama <o_osama at live.com>
> Date: Thu, 13 Oct 2011 16:07:13 +0200
> To: <equest-users at lists.onebuilding.org>
> Subject: [Equest-users] U-Value unexpected impact
>
>   All,
>     I'am modelling a mid-rise, curtain wall, office building in Egypt (hot
> humid climate 2a). while I do decrease the glazing's U-value, below 0.5, the
> energy consumption tends to increase. does this issue have a reality related
> explanation, is it a problem in my file, or is it a software bug issue?
>
>
>  Thanks for consideration,
>
>  Omar AlRawi
> Project Engineer ,  EA Sustainable Building Consultants
> www.ea-buildingconsultants.com
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