Camille,
If you are looking for heat transfer from surfaces to the zone
air node, I would suggest using:
Surface Int Convection Heat
Gain to Air
If you are also interested in radiative heat transfer from the
surface you might be able to use:
Opaque Surface Inside Face
Conduction
To use this variable you have to specify
“DisplayAdvancedReportVariables” under Output:Diagnostics. This value should be
close to the total convective and radiative heat transfer from the surface.
Neal Kruis
From:
EnergyPlus_Support@xxxxxxxxxxxxxxx [mailto:EnergyPlus_Support@xxxxxxxxxxxxxxx] On
Behalf Of hvacgeshen516
Sent: Wednesday, June 03, 2009 2:34 AM
To: EnergyPlus_Support@xxxxxxxxxxxxxxx
Subject: [EnergyPlus_Support] Re: About exterior surface convection
coefficient algorithms in EP
Thanks for your reply =)
I get your idea, maybe.
In TAS, exterior surface convection coefficient is calculated :
hc=5.8+4.1Vm CIBSE
In IES,
hc=5.6+4V V<4.88; hc=7.2V^0.78 V>4.88
they are both stating these formulas are used for calculating surface
convection. However,when calculating exterior surface long wave radiation, they
do not involve the radiation between surface and air..
this means this radiation part has been added to convection.
In EnergyPlus,
if "simple" is chosen for exterior surface convection, long wave
radiation is added to convection and calculated together;
if other algorithms except "simple" are chosen, the long wave
radiation between surface and air will be calculated separately.
Correct?
Thanks again =)
xiangjing
--- In EnergyPlus_Support@xxxxxxxxxxxxxxx,
Ben Polly <pollyben@...> wrote:
>
> The simple model calculates combined convective and radiative heat
transfer coefficients. Are you subracting off the contstant radiative
portion when you compare to other algorithms? I'd also look into how the
wind speed conversion (from weather station to surface centroid) affects your
convection coefficients.
>
> Ben
>
>
>
> ________________________________
> From: hvacgeshen516 <geshen516@...>
> To: EnergyPlus_Support@xxxxxxxxxxxxxxx
> Sent: Tuesday, June 2, 2009 12:56:38 AM
> Subject: [EnergyPlus_Support] About exterior surface convection
coefficient algorithms in EP
>
>
>
>
>
> If the algorithms except simple are chosen, the wind-driven convection
coefficient will be much smaller than algorithms implemented by other software
like TAS or IES.
>
> Is there any comments on this?
>
> Thanks and Regards
> Xiangjing =)
>
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