RE: [EnergyPlus_Support] Wall condensation

["Ian Doebber" <ian.doebber@xxxxxxxx>]

I agree with Josep that if you are looking at a specific envelope construction, the thermal bridging especially if it contains metal will require 2D or 3D conduction modeling.  

 

Use the results from this analysis to determine the location on the internal face of the construction that experiences the lowest level of insulation.  For example, if you are running winter case where the outside temperature is 30 F and the inside setpoint is 70, then find the lowest wall surface temperature.  Use this temperature and external boundary condition to determine what the R-Value is for that thermal bridge.  

 

Here is where E+ can be useful.  Apply that R-Value to the wall construction in Energy Plus and run it for the entire year with the correct weather and interior control points.  Find out how many times condensation occurs which energy plus does output, (look it up in the input-output ref).  Based on that, you can go back to your 2D or 3D analysis and either change your construction somewhat or the easiest thing is apply continuous rigid insulation on the interior surface underneath the gypsum board.  Then calculate the R-value of the thermal bridge and rerun the E+ analysis.  

 

This will give you a good idea of how the envelope will perform across the year and help you understand what measures you need to take to improve the envelope construction.  Remember that this is a very conservative analysis so if condensation only occurs for a few hours of the year, not worth worrying about.  Don't forget to look at the window construction, especially framing as this will probably be something that will cause more condensation issues than a respectable wall construction.

 

Hope this helps.

 

 

Ian

 

 

 

________________________________

From: EnergyPlus_Support@xxxxxxxxxxxxxxx [mailto:EnergyPlus_Support@xxxxxxxxxxxxxxx] On Behalf Of josep.sole@xxxxxxxxxxx
Sent: Wednesday, May 23, 2007 3:28 AM
To: EnergyPlus_Support@xxxxxxxxxxxxxxx
Subject: RE: [EnergyPlus_Support] Wall condensation

 

Internal wall condensation is mainly a 2D or 3D heat transfer problem ENERGY+ can not (in my opinion) run these kind of calculations, consequently any report coming from E+ will not be very accurate for wall condensation prediction.

Josep Sole 
URSA Iberica Aislantes SA 
www.ursa.es <http://www.ursa.es <http://www.ursa.es> > 

________________________________

De: EnergyPlus_Support@xxxxxxxxxxxxxxx <mailto:EnergyPlus_Support%40yahoogroups.com>  [mailto:EnergyPlus_Support@xxxxxxxxxxxxxxx <mailto:EnergyPlus_Support%40yahoogroups.com> ] En nombre de Miguel Angel Pascual
Enviado el: miércoles, 23 de mayo de 2007 11:51
Para: EnergyPlus_Support@xxxxxxxxxxxxxxx <mailto:EnergyPlus_Support%40yahoogroups.com> 
Asunto: [EnergyPlus_Support] Wall condensation

Hello:

I would like to know if energyplus can report wall condensation in the
inside face of the walls.

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 <mailto:mapascual%40miyabi.es>  <mailto:mapascual%40miyabi.es> 

Web: <http://www.miyabi.es/ <http://www.miyabi.es/>  <http://www.miyabi.es/ <http://www.miyabi.es/> > > www.miyabi.es

[Non-text portions of this message have been removed]

[Non-text portions of this message have been removed]

 

____________________________________________________________
Electronic mail messages entering and leaving Arup  business
systems are scanned for acceptability of content and viruses


[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.pdf under the Documentation link and press the "search" button.
 
Yahoo! Groups Links

<*> To visit your group on the web, go to:
    http://groups.yahoo.com/group/EnergyPlus_Support/

<*> Your email settings:
    Individual Email | Traditional

<*> To change settings online go to:
    http://groups.yahoo.com/group/EnergyPlus_Support/join
    (Yahoo! ID required)

<*> To change settings via email:
    mailto:EnergyPlus_Support-digest@xxxxxxxxxxxxxxx 
    mailto:EnergyPlus_Support-fullfeatured@xxxxxxxxxxxxxxx

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

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