[Equest-users] Queries

Tue May 4 12:45:14 PDT 2010

Hi all,

Second Law of Thermodynamics, heat flows from hot body to cold body, thus a
pos/neg sign convention necessary: cooling load positive, heating load
negative.

Regards,
Carol

On Tue, May 4, 2010 at 8:51 AM, Piyush Varma <varpiyush at gmail.com> wrote:

> Hi,
> thank you all...again the alternating solar gain factor is thorn in my
> flesh...i was actually looking for  hourly data for New Delhi for eight
> orientations (N,S,E,W,NW,NE,SW,SE)...
> just in case anybody is familiar with the Admittance Procedure here is the
> formula
>
> Qs(swing)-Swing in Fluctuating gains for Transparent surfaces.
> A-Area of the glazing
> I-Intensity
> S-Solar Gain Factor
>
> Formula
> *Qs(swing)=A X I(swing) X S(swing)*
> where, I(swing)=Intensity(at time t) - Average Intensity
> & S(swing)=S(at time t)-Average S
>
> here is what Nick had suggested...but having tried that i didnt quite get
> the right results...maybe i am doing some thing wrong.....I would get S=.86
> for all sunshine hours(mult factor=1) & S=0 for the night(& early morning)
> hours when there is no sunshine (mult factor=0) but here is a gist of the
> previous brainstorming session..
>
>
> 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.
>
>
>
>
> On Tue, May 4, 2010 at 8:02 PM, Nick Caton <ncaton at smithboucher.com>wrote:
>
>>  Piyush,
>>
>>
>>
>> Off the list here, please do not (on my account) hesitate to copy any of
>> our previous off-list discussion regarding alternating solar gain factors –
>> not everyone maintains an archive to look up your previous query easily.
>>
>>
>>
>> I’m do not think I have understood exactly what you’re looking for, but
>> weren’t you essentially trying to extract an hourly output for solar
>> admittance to a space to check against a separate simulation’s?   As a
>> humble suggestion, framing your question to the list with some additional
>> context regarding your purpose might help others to guide you to what you’re
>> looking for ;).
>>
>>
>>
>> Best wishes as always,
>>
>>
>>
>> ~Nick
>>
>>
>>
>> [image: cid:489575314 at 22072009-0ABB]**
>>
>> * *
>>
>> *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:* equest-users-bounces at lists.onebuilding.org [mailto:
>> equest-users-bounces at lists.onebuilding.org] *On Behalf Of *Demba Ndiaye
>> *Sent:* Tuesday, May 04, 2010 9:02 AM
>> *To:* Pasha Korber-Gonzalez; Piyush Varma
>>
>> *Cc:* equest-users at lists.onebuilding.org
>> *Subject:* Re: [Equest-users] Queries
>>
>>
>>
>> It make think of the sign convention used in Thermodynamics. You have the
>> System and its Surroundings. Let’s say that the System is the building.
>>
>>
>>
>> In Thermo, heat received by the system from its surroundings (cooling
>> load) is “positive”. The heat lost by the system to its surroundings
>> (heating load) is “negative”.
>>
>>
>>
>> It is the inverse for work.
>>
>>
>>
>> _____________
>>
>> Demba NDIAYE
>>
>>
>>
>> *From:* equest-users-bounces at lists.onebuilding.org [mailto:
>> equest-users-bounces at lists.onebuilding.org] *On Behalf Of *Pasha
>> Korber-Gonzalez
>> *Sent:* Tuesday, May 04, 2010 5:25 AM
>> *To:* Piyush Varma
>> *Cc:* equest-users at lists.onebuilding.org
>> *Subject:* Re: [Equest-users] Queries
>>
>>
>>
>> Piyush,
>>
>>
>>
>> I can help with 01., but I do not understand the concept of alternating
>> solar gain factor that you are referring too, or maybe I just don't
>> understand the question exactly.
>>
>>
>>
>> For 01. I have always known the symbols of heating energy to be referenced
>> as (+) for cooling and (-) for heating although I can't give you the exact
>> reference this nomenclature comes from.  In terms of the positive for
>> cooling energy it is a description for heat energy being present in the
>> conditioned space(s)/building in terms of heat energy being gained (or
>> generated.)  Where the negative symbol is used to represent heating energy
>> this is describing that heat energy from the space/zone is being
>> lost via....whatever the mechanism (i.e. ext. wall or window conduction
>> losses, to exhaust air heat energy loss from the building, to infiltration
>> effects, etc.)
>>
>>
>>
>> As long as you can keep your symbols managed with in your own simulation
>> work don't let this little quirk stop you from reporting your numbers in
>> your preferred format.  It is good that you are asking these types of detail
>> questions so that you can ensure your own foundation of understanding for
>> the tools you use.  This is what makes a good energy simulator.   Keep
>> asking questions, this list is a HUGE benefit from my experience.
>>
>>
>>
>> pasha
>>
>> On Tue, May 4, 2010 at 2:55 AM, Piyush Varma <varpiyush at gmail.com> wrote:
>>
>> Hi all,
>>
>>
>>
>> I am an eQuest newbie and had 2 small queries which hopefully would be
>> answered.
>>
>>
>>
>> 01. What's the logic behind eQuest giving positive (+ve) Cooling Loads &
>> (-ve) negative Heating Loads. (I made an Admittance Method Algorithm & it
>> gives me the opposite values, eQuest i.e. negative cooling loads & +ve
>> heating loads, have checked all sign convention...can't figure out why? My
>> algorithm simulates for Delhi's (India) climate predominantly, cooling
>> loads.
>>
>>
>>
>> 02. I have asked this before...is there any library for data of
>> alternating solar gain factors, especially for Delhi, India. (As far as i
>> believe it does'nt take into account the alternating solar gain factor...)
>>
>>
>>
>> hope these get resolved soon, thanks in advance.
>>
>>
>>
>> Regards,
>>
>> Piyush
>>
>>
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>>
>
>
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