[BLDG-SIM] energy consumption of low-E glazing , why the cooling energy increases
Leonard Sciarra
leonard_sciarra at gensler.com
Mon Jul 30 07:05:32 PDT 2007
If cooling load is increasing with decreasing SC that would seem to
suggest that your lights are going on for more hours, check your day
lighting settings (if on). Also, with such high U-factors, the ambient
air ( I am assuming a warm hot climate ) may be also adding to your
cooling load.
Try adding some exterior shades and see what happens.
Leonard Sciarra, AIA, LEED ap
312.577.6580 (Dir)
G E N S L E R | Architecture & Design Worldwide
30 West Monroe Street
Chicago IL, 60603
312.456.0123
leonard_sciarra at gensler.com
________________________________
From: BLDG-SIM at gard.com [mailto:BLDG-SIM at gard.com] On Behalf Of nicole
chen
Sent: Monday, July 30, 2007 3:03 AM
To: BLDG-SIM at gard.com
Cc: bldg-sim at gard.com
Subject: [BLDG-SIM] energy consumption of low-E glazing , why the
cooling energy increases
What I did is define a new glass type with simplied method in detailed
model. Then replace the old glass with the new defined one. Can this do?
How to avoid the defauls percolate through the program? I check again
and find that there was no wrong with the conduction heat and solar
radiation through window .But the load due to occupancy
/lighting/euqipment of Glass Type II is higher than Glass Type I . And
the cooling energy of Glass type II is a little highter. It make me
confused. Why the load due to due to occupancy /lighting/euqipment was
different when Glass type changed.
And I doubt if the problem has something to do with OA load .
On 7/29/07, Karen Walkerman <kwalkerman at gmail.com> wrote:
Hi nicole,
I can't tell you why the heating energy of glass type II may be
lower
because of the better U-value. With Shading Coefficients almost
the
same, there should be little change in heat gain from solar
radiation
between the two types.
What method did you use to enter your data? You should be
careful of
defaults that can percolate through the program. For example,
the
window frame U-value may not be consistent, or the glass
spacer-type
may be different.
Another good place to look for some feedback is the building and
space
peak loads summary. Here, the solar gain (heat energy gained
through
radiation) and simple conditioning (energy transfered through
the
glass-same as walls), are broken out. The heating design case
will
not take solar radiation into account.
Hope this helps.
~karen~
On 7/29/07, nicole chen <cloris.chen at gmail.com> wrote:
> Dear all
>
> I have tried to compare the energy consumption between two
different glass
> types and got a curious result. The parameters of these two
glasses are
> listed below:
>
> 1) Coated U=2.5 SC=0.45
> 2) low-e U=1.76 SC=0.44
>
> I thought the energy consumption of Glass Type II would be
lower than that
> of Glass Type I . But the result is the cooling energy of
Glass Type II is
> higher than that of Glass Type I , and the heating energy
lower than that
> of Glass Type I.
>
> I have no idea of this. And I checked LS-F/ SS-D / BEPS and
found some
> points listed below
>
> 1) in LS-F annual sensible cooling load of Glass Type II is
lower than that
> of Glass Type I , latent cooling load of Glass Type II is
higher. The total
> annual cooling load of Glass Type II is a little higher
>
> 2) in SS-D monthly cooling energy of Glass Type II is higher
>
> 3) dencity and schedule of occupancy /lighting /euqipment are
the same in
> the two models , but cooling load and heating load due to
these indoor
> factors are different , why?
>
> 4) monthly schedule of occupancy /lighting /euqipment is all
the same
> during the year, but cooling load and heating load due to
these indoor
> factors are different every month, why?
>
>
>
> --
> Yours
> Nicole Chen
--
Karen Walkerman
Second Law Consulting
802-238-0980
kwalkerman at gmail.com
--
Yours
Nicole Chen
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