Re: [EnergyPlus_Support] Outside convective heat transfer coefficient

["Michael J. Witte" <mjwitte@xxxxxxxx>]

If you mean a WINDOWSHADE rather than a shading surface, exterior shades and 
blinds convect with the outside air and the airflow in the gap between the 
shade or blind and the outside glass layer is also modeled.  The gap flow is 
affected by temperature differences and by the shade or blind characteristics.  
In the case of the shade, the "Air flow permeability" is a factor in this 
calculation.  My understanding is that the reported convection coefficients are 
for the shade or blind convecting to the outside air, not the effective 
convection coefficient for the glass layer, but I am not 100% sure of this.  
The Engineering Reference discusses shading layer heat balances in detail, see 
"Heat Balance Equations for Shading Device and Adjacent Glass", beginning on p. 
191, pdf p. 219.   

Mike



On 16 Feb 2006 at 5:29, Linda Lawrie wrote:

> At 02:28 AM 2/16/2006, Peter G Loutzenhiser wrote:
> >If I have a an exterior shade mounted over a glazing unit, what is
> >the output for the exterior convective heat transfer coefficient
> >giving me is it the heat transfer coefficient on the outer window
> >surface or the outer shading surface?
> 
> Since shading surfaces are NOT heat transfer surfaces, the exterior 
> convective coefficent reporting is on outer window surface.
> 
> 
> Linda
> 
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========================================================
Michael J. Witte, GARD Analytics, Inc.
EnergyPlus Testing and Support      
EnergyPlus-Support@xxxxxxxx





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