[Bldg-sim] Building Heat Gains

[Joe Huang]

Sambhav,

What do you mean when you say that the conduction gains have increased?  
Do you mean that there's less conduction heat flow entering the 
building, or more ?  If it's the former, that makes a lot of sense, 
since the shading is cutting off solar gain on the wall/window, thus 
lowering its surface temperature (or more exactly, sol-air temperature) 
and reducing heat flow into the building.  If it's the latter, that 
would be problematic, since I don't see how reducing solar gain would 
increase conduction heat flow entering the building.

Joe

Joe Huang
White Box Technologies, Inc.
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On 11/24/2014 7:00 AM, Andrew Corney wrote:
> Hi Sambhav,
>
> Yeah - I'd agree with Cory - you probably have a higher glazing 
> surface temperature with the unshaded model and I wouldn't be 
> surprised if that is part of the conduction equation, meaning you are 
> less likely to gain heat through conduction if the glazing is in full sun.
>
> cheers,
>
> Andrew
>
> On Mon, Nov 24, 2014 at 2:55 PM, Duggin, Cory <Cory.Duggin at tlc-eng.com 
> <mailto:Cory.Duggin at tlc-eng.com>> wrote:
>
>     The VE doesn’t model thermal bridging, so that isn’t it.  What
>     climate is your building in?  What percentage glazing are the east
>     and west walls? Are you losing heat through the envelope or
>     gaining it?  It could have to do with the shades blocking more sun
>     from heating up the outside of the envelope on those walls, which
>     then changes the delta T and resulting conduction gain.
>
>     *Cory Duggin, EI, LEED AP BD+C *
>
>     /Associate/Energy Engineer/
>
>     *TLC Engineering for Architecture *
>
>     direct:
>
>     	
>
>     615-346-1939 <tel:615-346-1939>
>
>     *From:*Bldg-sim [mailto:bldg-sim-bounces at lists.onebuilding.org
>     <mailto:bldg-sim-bounces at lists.onebuilding.org>] *On Behalf Of
>     *Sambhav Tiwari
>     *Sent:* Monday, November 24, 2014 2:21 AM
>     *To:* Attiq
>     *Cc:* bldg-sim
>     *Subject:* Re: [Bldg-sim] Building Heat Gains
>
>     Hi All,
>
>               Thanks for the reply this analysis was done in ies ve
>     and the external conduction gains are increasing with shading
>     while solar gains are reducing
>
>     i am sending the snapsort of the building with shading in east and
>     west
>
>     Regards
>
>     Sambhav
>
>     On Sat, Nov 22, 2014 at 9:46 PM, Attiq <aur at bepc.biz
>     <mailto:aur at bepc.biz>> wrote:
>
>     The shades are attached to the building exterior and there is no
>     thermal break between the shades and the exterior walls. The
>     shades act as fins conducting heat to the outside.
>
>     Attiq
>
>     Sent from my iPhone
>
>
>     > On Nov 22, 2014, at 7:15 AM, Sambhav Tiwari
>     <tiwari.sambhav at gmail.com <mailto:tiwari.sambhav at gmail.com>> wrote:
>     >
>     > Dear All,
>     >                I am analyzing a rectangular building with each
>     and west facades structured glazed and forming longer sides of
>     rectangle  and i shaded these facades with louvers (shading device)
>     >
>     > I compared the annual heat gains of two case1 building with no
>     shading case 2 building with shading(louvers) what i found was
>     there is considerable reduction in annual solar gains in building
>     but the annual external conduction gains in building have
>     increased after shading i am unable to understand this.
>     >
>     > Any one who can share his ideas on this.
>     >
>     >
>     > Warm Regards
>     > Sambhav Tiwari
>
>
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>
> -- 
> Andrew Corney
> PE M.CIBSE M.ASHRAE
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