Re: Antw: [EnergyPlus_Support] window surface temperature

["Achim Geissler" <Achim.Geissler@xxxxxxxxxxxxxxxx>]

Alan,

radiation on the ouside wall is somewhat different from the window, as
the wall has zero transmission. What are you using for solar absorption
/ reflection? Solar absorption for clear glass is somewhere around 8 to
15 %. Solar absorption of wall materials can easily be 70 to 80%.
Additionally, the heat transfer to the inside will (hopefully) be very
limited due to a small U-value.

Achim


>>> pizzaalan@xxxxxxxxx 18.05.2004  18.35 Uhr >>>
Dear Achim and Griffith

Thank you for your help. It makes sense, the radiation to ouside 
might be more than its to the inside. Also I check the convection 
coefficient, the outside coefficient is around 3 times than inside.
But then why the outside wall temperature is much higher than inside 
wall temperature?  Although the outside coefficient is also higer 
than inside and radiation situation is pretty simialr to window's (I 
guess).

Alan




--- In EnergyPlus_Support@xxxxxxxxxxxxxxx, "Achim Geissler" 
<Achim.Geissler@S...> wrote:
> Alan,
> 
> as first idea: Check your long wave radiation surrounding. Indoor 
will
> have eps of approx 0.9, probably and a surface temperature of ??.
> Outdoor long wave radiation temperature will be around air 
temperature,
> probably. Thus, the surface temperature difference of 0.2 K for the
> single pane could easily be explained.
> 
> Achim
> 
> 
> >>> pizzaalan@y... 17.05.2004  23.59 Uhr >>>
> There is a problem I don't understand. I let E+ report all the 
> surface temperatures. I found that in summer condition,  the 
> exterior wall inside temperature (35.29 C) is much lower than wall 
> outside temperature (53 C ). This makes sense since the wall is 
> exposed to sun. However,the window inside temperature (32.8 C) is 
a 
> little bit higher than window outside temperature (32.6). How 
could 
> this be possible? The window is also exposed to sun, should have a 
> higher temperature. That is just a single pane window which 
> definately on that exterior wall.  
> 
> Firstly I doubt that my input might be wrong, but I tried those 
> example files and reported surface temperatures. It is same. So 
> anyone knows why it is, please let me know. Thanks a lot.
> 
> Sincerely,
> Alan
> 
> 
> 
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