[Bldg-sim] Impact of Overhangs

leen peeters l.f.r.peeters at gmail.com
Sun Feb 7 01:09:11 PST 2010


Fareed,

it will strongly depend on the glass-quality (and the thermal quality of the
walls) and the orientation, as well as on the climate. In fact even on the
efficiency of the production of electricity for light, and the way the
cooling and heating is done.
In fact you should take all of them into account when doing your
optimisation study. Using ESP-r, coupled with GenOpt, I once had the sizes
of the windows determined as a function of the consumed energy for lighting,
cooling and heating. You could add overhangs and optimize their width as
well. And of course, the code does not have to be ESP-r ....

Leen Peeters

On Sat, Feb 6, 2010 at 5:59 PM, John Aulbach <jra_sac at yahoo.com> wrote:

>  Maria:
>
> Excellent information.
>
> Would you please describe what you mean by "free running mode"?
>
> Thank you.
>
>  ------------------------------
> *From:* Maria Kordjamshidi <m_kordjamshidi at yahoo.com>
> *To:* BldgSim Mailing List <bldg-sim at onebuilding.org>;
> equest-users at lists.onebuilding.org; trace-users at lists.onebuilding.org;
> Fareed Syed <syedf at progressiveae.com>
> *Sent:* Fri, February 5, 2010 9:47:04 PM
> *Subject:* Re: [Bldg-sim] Impact of Overhangs
>
>   Fareed
>
> I have examined the effect of many parameters on the thermal performance of
> 6 typical houses (single storey and double storey houses) for a moderate
> climate of Sydney. a part of my report comes in the following for your
> consideration.
>
> "Adding an overhang above all windows improved annual thermal performance
> of the typical houses in conditioned mode. However, this was not the case
> for the houses in free running mode. The houses presented different patterns
> of annual thermal performance in the different modes, responding to
> increments in overhang width.
>
> Increases in overhang width of 1m resulted in an average of 4.8%
> enhancement in the house’s annual thermal performance in conditioned mode.
> The same overhang generally caused 3.7% deterioration in annual free running
> performance, while a slight improvement was observed in thermal performance
> in some cases.  The reason for these different results is made clear when
> comparing the seasonal performances of each house in two different house
> modes.
>
> When all the overhang widths were increased to 1m, the summer performance
> improved by an average of 26.6% in conditioned mode. The improvement
> decreased to an average of 8% for all houses in free running mode. The
> winter performance of the typical houses in this situation deteriorated by
> an average of 8.2% in conditioned mode and 11.7% in the free running mode.
> Thus the deterioration that was observed in the annual free running
> performance of some of the houses in response to the setting of overhang
> with a width of 1m for all windows would appear to owe more to deterioration
> in their winter performance and less improvement in their summer performance
> in free running mode than in conditioned mode."
>
>
>
>
> Hope this help
>
> Maria
>
>
>
> --- On *Sat, 2/6/10, Fareed Syed <syedf at progressiveae.com>* wrote:
>
>
> From: Fareed Syed <syedf at progressiveae.com>
> Subject: [Bldg-sim] Impact of Overhangs
> To: "BldgSim Mailing List" <bldg-sim at onebuilding.org>,
> equest-users at lists.onebuilding.org, trace-users at lists.onebuilding.org
> Date: Saturday, February 6, 2010, 12:22 AM
>
>  Folks,
>
>
>
> Does anyone have good research data using simulations on the impact of
> overhangs and shadings for a typical building?
>
>
>
> I am having hard time convincing architects to reduce the glazing. They
> will make it a glass building if they are given a chance.
>
>
>
> I want to show them that for a 2 or 3 storied building with ton of glazing
> and few feet of overhang will not help the cooling/heating loads at all.
>
>
>
> I would appreciate your input.
>
>
>
> Thanks much.
>
>
>
>
>
> Fareed Syed EIT, LEED® AP
>
> Mechanical Engineer* *
> [image: cid:image001.png at 01C9B834.C9D7E7F0]
>
> 1811 4 Mile Rd NE
> Grand Rapids, MI  49525
>
>
>
> Phone: 616.361.2664 ext. 3247
> Direct: 616.447.3447
> Fax: 616.361.1493
>
> syedf at progressiveae.com<http://us.mc514.mail.yahoo.com/mc/compose?to=syedf@progressiveae.com>
> www.progressiveae.com
>
>
>
>
>
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