Re: [EnergyPlus_Support] External wall U value setting

["Jean Marais jeannieboef@xxxxxxxxx [EnergyPlus_Support]" <EnergyPlus_Support@xxxxxxxxxxxxxxx>]

No, you have to do it manually or use a program like DesignBuilder which has this utility for the ISO EN DIN norm or use a spreadsheet to find out how thick your insulation layer should be.

U-value is a rating system. You can deturmine the U-value of an assembly differently, depending on what norm you are using as a base (which itself sets certain airfilm coefficients, delta Temperatures and thermal bridging effects). EnergyPlus reports the u-value, both air to air and surface to surface based on ASHRAE 90.1 for the film coefficients, and assumes that the user has setup his assembly in such a way as to reflect the degradation due to thermal bridging effects (such as those in App. A of standard 90.1). Usually, we degrade the insulation thickness untill the rated U-value matches that of the assembly product specification, but you need to check that the assembly product uses the same norm. That being said the differences between some norms (for example ASHRAE and DIN) are negligable.

2015-10-06 8:48 GMT+02:00 muminegercek@xxxxxxxxx [EnergyPlus_Support] <EnergyPlus_Support@xxxxxxxxxxxxxxx>:

 

Hi,

Is it possible to set U values of external walls in Energy Plus? I would like to give specific value instead of changing thermal properties (specific heat, conductivity etc) of each layer one by one.

Sincerely

Mümine

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Posted by: Jean Marais <jeannieboef@xxxxxxxxx>

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