Warning: glass system and gravity vector orientation

[Adriana Aranda]

Hi Robin, I am having troubles simulating a curtain Wall, this polygon is the frame of the curtain wall that is located over the concrete floor, the frame type I gave it is Head (as it is the head divider of the curtain wall module) and I assigned the boundary conditions according to Figure 8-96. Head Boundary Conditions (head_boundary.thm) of section 8. Special Cases of the Simulation Manual, then, according to Figure 6-4 of section 6.3 Draw the Cross Sections I put the gravity arrow towards down but then I try to simulate the program and this warning shows up. What should I do?

I am running THERM 7.4

[Robin Mitchell]

Adriana

Without the THERM file it is hard to know exactly how it is defined, but the program determines the Gravity arrow based on the Cross Section Type, defined in File/Properties. Here is a screen shot of that dialog box -- in your case you should set the Cross Section Type = Head, and then the Gravity arrow should automatically get set to down. If you have the Cross Section Type set to something that would not by default have a gravity arrow pointing down, but you manually set it to down, you could expect the message that you are getting. It is not an error message, it is informative, and you can proceed with the simulation if you think everything is defined properly. Check the Cross Section Type, and if it is not set to Head, change it to that option, then see if the message goes away. 

Robin

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Robin Mitchell
Building Technology and Urban Systems Department
Environmental Energy Technologies Division
Lawrence Berkeley National Laboratory

[Adriana Aranda]

Actually that is the problem, I set the Cross Section as Head in the Properties of the File, but the Gravity Arrow sets Up automatically, so I manually changed it towards Down and that´s when the message appeared. Here is the THERM file if you have the chance to see it. However, if you say that the Warning is just informative, I will not pay attention to it and go on with the simulation. Thank you Robin!

El martes, 21 de febrero de 2017, 12:46:47 (UTC-6), Robin Mitchell/LBNL escribió:

Adriana

Without the THERM file it is hard to know exactly how it is defined, but the program determines the Gravity arrow based on the Cross Section Type, defined in File/Properties. Here is a screen shot of that dialog box -- in your case you should set the Cross Section Type = Head, and then the Gravity arrow should automatically get set to down. If you have the Cross Section Type set to something that would not by default have a gravity arrow pointing down, but you manually set it to down, you could expect the message that you are getting. It is not an error message, it is informative, and you can proceed with the simulation if you think everything is defined properly. Check the Cross Section Type, and if it is not set to Head, change it to that option, then see if the message goes away. 

Robin

On Tue, Feb 21, 2017 at 8:21 AM, Adriana Aranda <aar...@bioconstruccion.com.mx> wrote:

Hi Robin, I am having troubles simulating a curtain Wall, this polygon is the frame of the curtain wall that is located over the concrete floor, the frame type I gave it is Head (as it is the head divider of the curtain wall module) and I assigned the boundary conditions according to Figure 8-96. Head Boundary Conditions (head_boundary.thm) of section 8. Special Cases of the Simulation Manual, then, according to Figure 6-4 of section 6.3 Draw the Cross Sections I put the gravity arrow towards down but then I try to simulate the program and this warning shows up. What should I do?

I am running THERM 7.4

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[Robin Mitchell/LBNL]

I didn't do "reply all" so my reply didn't make it back to the forum, but thought I would put it in this thread anyway.

*******

I re-read the NFRC Sim manual for this case, and I guess because you are modeling the "head" and the "sill" separately in terms of U-factors, the rule is to set it to Property Type = Head. 

But in reality, this model is actually Type = Horiztonal Divider. 

So I took your file and ran it both ways

- Type set to Horizontal Divider, gravity arrow down, which does not issue a warning message

- Type set to Head, gravity arrow down, which results in warning message

Both of the IR images + the U-factor results were identical. 

The reason the warning message appears for the Head type is that there is the upper glazing that is oriented up, which would normally be for a Sill, so the program gives the warning. 

In this case, you can ignore the warning. 

Robin

[Robin Mitchell/LBNL]

Actually, my reply below is not quite correct.

As Adriana correctly pointed out, the gravity arrow is Down for both Head and Sill. 

Robin 

On Tuesday, February 21, 2017 at 8:21:46 AM UTC-8, Adriana Aranda wrote: