3D thermal bridges

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Fuadbaba
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3D thermal bridges

Post by Fuadbaba » Thu Nov 05, 2015 6:09 am -1100

Please I want to know the meaning and the difference between the "Terminologies" in the "Boundary conditions" list in 3D object , such as:
* Climate: this term has Rs = 0.04 m2.K/W for out side(which is reasonable) but the short wave and long wave is 0 (which is not reasonable)
* while, West Azimuth 270 inclination 90: this term has Rs = 0.13 m2.K/W for outside (which is not reasonable) but the short wave and long wave is 0.4 , 0.9 (which is reasonable) and the same values for North, East and South.
* zone1 South... etc
When and where can we use each one?

Thanks

mpazold
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Re: 3D thermal bridges

Post by mpazold » Sun Nov 08, 2015 10:31 pm -1100

If you choose "climate" as boundary conditions, the 3D-Object doesn't know about the orientation of the object surfaces, so the solar radiation is not regarded in this case.
You have to choose the boundary conditions from a component (the outer side condition of this component) for the object, then the same solar radiation is used for the 3D-object. This is why absorbtion an emission is not zero for "component xzy" boundary conditions but for the "climate" condition.

Of cause, we will check Rsi, if you choose the component. meanwhile you may can deactivate "use component settings" and input the heat transfer resistance uesr defined.

stevebe
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Re: 3D thermal bridges

Post by stevebe » Sun Jan 20, 2019 4:34 pm -1100

It appears that for 3D objects, the component boundary conditions do not include any shading calculation.

The component boundary condition includes the exterior temperature, and includes the solar radiation determined by orientation and absorptivity, but the shading of the component is not taking into consideration for calculation of the solar radiation.


Is there any way to include the appropriate shading or solar radiation as the part of the component boundary conditions for 3D objects in WUFI Plus?

mpazold
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Re: 3D thermal bridges

Post by mpazold » Fri Mar 15, 2019 12:28 am -1100

For a constant shading factor, you can regard the shading with the absorptivity factor.

for a hourly dependend shading factor, the workaround is not simple done. You have to do a first simulation, to get teh solar shaded radiation (W/m²) on a component, then you can set this, and temperature and relative humidity as external measured data file for the coponent. and use this as optional climate for the boundray conditions, for the 3D-Object.

stevebe
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Re: 3D thermal bridges

Post by stevebe » Sun Jul 14, 2019 7:53 pm -1100

Hi mpazold,

Thanks for replying to my question.

I understand how to export the component boundary conditions (outside temperature, outside relative humidity, and total incident Solar Radiation (with shading considered)) to a *.CSV or a *.txt file by simply indicating to "Retain Calculation Results" for the specified component, running the simulation, and then using the Export feature within WUFI+.

Could you please indicate the most appropriate method to covert this data into a climate file.
I presume that I need to somehow save the file as a *.wac file? Is there a way to do this with WUFI+? I do not currently have access to WUFI Pro, which I believe comes with an excel tool to generate .wac files. Is there some way to access this tool or otherwise generate the appropriate file?

Once I have the climate file, I see you have instructed me to go to the Optional Climates and from there, the climate will appear in the list of boundary conditions within the 3D Object list.

I have tested and confirmed this is okay with a Sine Curve or other prescribed Optional Climate; However, I am unsure of how to import the climate file into the Optional Climate. I see that there is an option for "File Based", but I couldn't find where to specify the file directory (despite myself, not even having an optional climate file prepared).

Thank you very much for your resolute support.

Regards,
Steve

stevebe
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Re: 3D thermal bridges

Post by stevebe » Sun Jul 14, 2019 8:14 pm -1100

I would just like to add that I was able to find the climate tool within the WUFI+ Directory under tools. Who would have thought! (my apologies).

I will give it a go and report back.

I also did read within the WUFI+ Manual that for the Optional Climates:

”File based refers to a previously uploaded climate file in ”Files/MeasuredData”. I'm now going to look for this folder.
Edit - Deary me, I found within the Software, within the Project Directory "Tree", above the list of Cases.

Apologies for these few now redundant questions, I haven't used WUFI since posting my original question. I will now attempt to integrate my 3D object with the appropriate solar-based boundary conditions and report back.

Edit2 - I think simply saving the air temperature, humidity, and total solar incident radiation as a *.csv seems to be the most effective way to import it into the Optional Climate. The File/MeasuredData did not interpret the .*wac file very well, and I thought to try a simple csv rather than tinker with the *.wac import settings.

Kind Regards,
Steve

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