Re: [EnergyPlus_Support] New file uploaded to EnergyPlus_Support

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

Thank you, Clemens, for a clear explanation.  Turning on the report 
variables for "Surface Inside Temperature" and "Surface Outside 
Temperature" helps illustrate what is happening.  At midday, the 
outdoor air temperature is 30C, the inside air temperature is 24C 
(controlled), the ceiling inside surface temperature is 54C, and 
inside surface temperatures of the walls range from 35C to 44C.  The 
walls at 35C all show a slightly lower outside surface temperature 
which leads to negative values reported for "Opaque Surface Inside 
Face Conduction".  However, these surfaces are still hotter than the 
zone air and contribute to the zone cooling load.  They are warmed by 
radiant transfer from the hot surfaces, most of the energy goes into 
the zone air, but a small amount is conducted to the outside.

Mike



On 21 Nov 2002, at 9:20, Clemens Felsmann wrote:

> Hello,
> 
> in the same folder there is a new file now: help.xls. 
> If you take a look at the temperature profiles you can see the
> different orientations of the walls. The negative surface conduction
> values may be  caused by three effects: 1) very thin wall
> constructions, 1cm, 2) solar radiation 3) longwave radiation exchange
> within the room.
> 
> This means that solar radiation leeds to high outside surface
> temperatures. Because of a low thermal resistance of walls the inside
> surface temperature is very similar to the outside surface
> temperature. In dependence of the sun's position the walls
> temperatures change during a day. In the morning the eastwall is the
> warmest, In the afternoon the westwall is the warmest und during noon
> it is the ceiling which is warmest. Because of langwave radiation
> effects the warmest wall works as a radiative heater. This means the
> inside surface temperature of the other more colder surfaces gets
> higher than the outside one and inside surfcae conduction is below
> zero. So, increasing the thickness of the walls or reduce their
> conductivity could help.
> 
> Clemens
> --
> 
> Dr.-Ing. Clemens Felsmann
> Institut für Thermodynamik und TGA der TU Dresden
> Tel.: 0351/463 3 5177
> Fax: 0351/463 3 7888
> mail: felsmann@xxxxxxxxxxxxxxxxx
>   ----- Original Message ----- 
>   From: EnergyPlus_Support@xxxxxxxxxxxxxxx 
>   To: EnergyPlus_Support@xxxxxxxxxxxxxxx 
>   Sent: Wednesday, November 20, 2002 6:00 AM
>   Subject: [EnergyPlus_Support] New file uploaded to
>   EnergyPlus_Support
> 
> 
> 
>   Hello,
> 
>   This email message is a notification to let you know that
>   a file has been uploaded to the Files area of the EnergyPlus_Support
>   group.
> 
>     File        : /Problem_Submittals/question/help.idf 
>     Uploaded by : gagamere <gagamere@xxxxxxxxxxx> 
>     Description : check a minus cooling load 
> 
>   You can access this file at the URL
> 
>   http://groups.yahoo.com/group/EnergyPlus_Support/files/Problem_Submi
>   ttals/question/help.idf 
> 
>   To learn more about file sharing for your group, please visit
> 
>   http://help.yahoo.com/help/us/groups/files
> 
>   Regards,
> 
>   gagamere <gagamere@xxxxxxxxxxx>
> 
> 
> 
> 
> 
> 
>   To unsubscribe from this group, send an email to:
>   EnergyPlus_Support-unsubscribe@xxxxxxxxxxxxxxx
> 
>   The primary EnergyPlus web site is found at:
>   http://www.energyplus.gov
> 
>   The group web site is:
>   http://groups.yahoo.com/group/EnergyPlus_Support/
> 
> 
> 
> 
> 
> 
>   Your use of Yahoo! Groups is subject to the Yahoo! Terms of Service.
>   
> 



========================================================
EnergyPlus Testing and Support      
EnergyPlus-Support@xxxxxxxx


------------------------ Yahoo! Groups Sponsor ---------------------~-->
Get 128 Bit SSL Encryption!
http://us.click.yahoo.com/CBxunD/vN2EAA/xGHJAA/dkFolB/TM
---------------------------------------------------------------------~->

To unsubscribe from this group, send an email to:
EnergyPlus_Support-unsubscribe@xxxxxxxxxxxxxxx

The primary EnergyPlus web site is found at:
http://www.energyplus.gov

The group web site is:
http://groups.yahoo.com/group/EnergyPlus_Support/




 

Your use of Yahoo! Groups is subject to http://docs.yahoo.com/info/terms/