Re: [EnergyPlus_Support] Problem: low temp radiant + window frame

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

The window heat gain/loss values seem way too high even without the frame.  
With frame, the peak "RESISTIVE ZONE:Zone Window Heat Gain[W](Hourly)" is 68kW. 
 Without the frame, it is 56kW.  With a non-radiant system (such as 
TermReheat.idf which is the same building envelope), the max window heat gain 
is 3.4 kW.  

It appears to me that the reported window heat gain/loss may be in error when 
using radiant systems.  There is already a known issue with the reporting of 
the window frame portion of the window heat gain heat loss.  The window heat 
gain/loss reported values are computed using a simplified calculation just for 
reporting purposes.  It appears that this is not matching what is actually 
happening on the zone heat balance.  If you look at the chilled water/hot water 
loads for RadLoTempHydrHeatCool vs. TermReheat, they are the same order of 
magnitude.  So this appears to be just a reporting problem, not an energy 
balance problem.  This is a new change request (CR 6897).

Mike




On 3 Feb 2006 at 13:49, Miguel Angel Pascual Buisan wrote:

> Hello,
> 
>  
> 
>  
> 
> I have noticed a problem when using ?LOW TEMP RADIANT SYSTEM:HYDRONIC? and
> ?WindowFrameAndDivider? in the windows. Under this combination, the window
> heat gain increases to impossible values.  
> 
>  
> 
> I have uploaded to the problems submittal area, the modified example:
> ?RadLoTempHydrHeatCoolepm.idf?. In this file, is quite easy to see the
> problem when switching on/off the WindowFrameAndDivider.
> 
>  
> 
> Can anybody have a look a it?
> 
>  
> 
> Thanks in advance,
> 
>  
> 
>  
> 
> Miguel Ángel Pascual
> 
> Director Técnico
> 
>  
> 
> MIYABI       espacios urbanos bioclimáticos
> 
> Leyre 11bis, 1ºC 31002 Pamplona
> 
> Tel: 948 20 36 44  Fax: 948 20 78 60
> 
> Email: mapascual@xxxxxxxxx
> 
> Web: www.miyabi.es <http://www.miyabi.es/> 
> 
>  
> 
> 
> 
> [Non-text portions of this message have been removed]
> 
> 
> 
> The primary EnergyPlus web site is found at:
> http://www.energyplus.gov
> 
> The group web site is:
> http://groups.yahoo.com/group/EnergyPlus_Support/
> 
> Attachments are not allowed -- please post any files to the appropriate folder
> in the Files area of the Support Web Site.
> 
> EnergyPlus Documentation is searchable.  Open EPlusMainMenu.idf and press the
> "search" button.
>  
> Yahoo! Groups Links
> 
> 
> 
>  
> 
> 
> 
> 


========================================================
Michael J. Witte, GARD Analytics, Inc.
EnergyPlus Testing and Support      
EnergyPlus-Support@xxxxxxxx





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