[Equest-users] Solar Gain Factor & Variable Infil Values

[Nick Caton]

Hi Piyush,

 

Apologies, I wasn't sure whether you meant SHGF.  

 

I did some googling to check my vocabulary and found this reference:  
http://www.levolux.com/L_PDF_Files/Lev. Comp Analysis Table.pdf
<http://www.levolux.com/L_PDF_Files/Lev.%20Comp%20Analysis%20Table.pdf> 

 

It looks like:  Solar Gain Factor (S Factor) = Shading Coefficient (SC)
* 0.87 

I can add that:  Shading Coefficient (SC) = (Center of Glass SHGF) /
0.87

 

So to answer your first question, while this is the first time I've
personally run into S Factors, it would appear they're analogous to a
center-of-glass SHGF, but can vary based on external shading devices
(including trees, curtains and shades) per the above.  I'm copying
eQuest-users to share the following procedure and to allow others to
correct any misunderstandings we may have regarding what S Factor really
means - I hope you don't mind!

 

So per your second inquiry to determine the hourly S Factors, and
because I was curious, here's a procedure:

-          Set up your windows and all variable shading items.

-          Create an hourly report/block for the window(s) in question
selecting the items shown in the  screengrab below - SC and "Value by
which..." SC multiplier for those of you in the archives.

-          Run the simulation and open the hourly results up in excel
(hit the 'hourly results' button in the sim viewer).

-          Multiply those values across to get your hourly effective SC,
and again by 0.87 to get an hourly S Factor.

 

 

 

Best of luck,

 

~Nick

 

 

NICK CATON, E.I.T.

PROJECT ENGINEER

25501 west valley parkway

olathe ks 66061

direct 913 344.0036

fax 913 345.0617

Check out our new web-site @ www.smithboucher.com 

 

From: Piyush Varma [mailto:varpiyush at gmail.com] 
Sent: Thursday, April 22, 2010 3:06 AM
To: Nick Caton
Subject: Re: [Equest-users] Solar Gain Factor & Variable Infil Values

 

Hi Nick,

 

Thanks a lot for your prompt reply & even more so for the detailed
account.

 

However, if you could resolve a few more of my queries i'd be greatly
obliged.

I wanted to ask whether Solar Gain Factor & Solar Heat Gain Factor are
the same...I believe they are different but honestly i don't know the
difference and I am actually looking for solar gain factor value or
alternating solar gain factor values(hourly).

 

Regards,

Piyush 

 

On Wed, Apr 21, 2010 at 3:56 AM, Nick Caton <ncaton at smithboucher.com>
wrote:

Piyush, I am but a humble user and not a developer or "expert," but I
can offer some fast suggestions - someone else may care to elaborate:

 

1.       The solar heat gain factor (SHGF) used depends on the window
selected.  Suggest checking out the DOE2 Glass Library if you haven't
already.  Right-click nearly any input field, select "Tutorials and
Reference" from the context menu, and select the DOE2 Glass Library
excel spreadsheet.

2.       If you asking whether the variability of solar heat gain (that
is, transmitted + absorbed radiation that flows inward) through a window
is accounted for, then the answer is yes.  That varies hourly based on
the changes of incident sunlight, as affected by the fixed window
orientation, any building shades and/or other self-shading elements.  If
instead you mean a variable shading coefficient (SC), as with automated
blinds and such, then the answer is also yes - via creating a custom
shading schedule.

3.       Variable infiltration and ventilation rates are both model-able
in eQuest, and are two distinct topics...

a.       For infiltration, suggest entering the detailed mode, opening
the properties for any space under "internal loads" tab, and exploring
the various infiltration methods that may be employed under the
infiltration tab, along with the corresponding help/dictionary entries.
The ACH rate method for example accounts for the hourly wind speed data
present in your weather file to determine the hourly ventilation rate.

b.      For ventilation, you may observe "constant" ventilation rates,
but only if you chose to model as such.  Be sure any and all methods of
varying the ventilation air rate are accounted for in your model.

 

Best of luck!

 

~Nick

 

Error! Filename not specified.

 

NICK CATON, E.I.T.

PROJECT ENGINEER

25501 west valley parkway

olathe ks 66061

direct 913 344.0036

fax 913 345.0617

Check out our new web-site @ www.smithboucher.com
<http://www.smithboucher.com>  

 

From: equest-users-bounces at lists.onebuilding.org [mailto:
equest-users-bounces at lists.onebuilding.org] On Behalf Of Piyush Varma
Sent: Tuesday, April 20, 2010 3:40 AM
To: equest-users at lists.onebuilding.org
Subject: [Equest-users] Solar Gain Factor & Variable Infil Values

 

Hi,
am a eQuest newbie, am doing some research wherein i need to know the
solar gain factor the windows use, also does eQuest take into account
Alternating Solar Gain Factor???I would also like to find out whether
variable infiltration flow rates (or variable ventilation values) are
taken into account??? the hourly report block i generated only gave me
same value for infiltration flow rates for all 24 hrs & for all 365
days.

Please help, this is regarding my Major Project at College & deadlines
are approaching.

Thanks in advance,

Regards,
Piyush Varma 

 

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