Q&A Simulating tilted glass

[Naeun Kim]

Hi everyone.

I'm currently working on how to calculated tilted glass.

As two glasses have different inclination, the head and jamb section is quite complex.

Firstly, tried to insert glass in inclined position; however, I knew glass imported from WINDOW only supports 90 degree when importing into THERM. 

So I thought I have no choice but to model section into 90 degree in cad, which can then insert glass from window, and tilt glass + frame whole again in THERM.

Here comes the problem and question.

1) Because two glasses have different inclination, I should divide frame into two parts and make them vertical.

2) In case of dividing frame, how can I make the right division? Two frame is originally connected, and the division is arbitrary.

3) To sum, in these kinds of situations, how can I organize model and the test? I have searched whole manual, but could not find this case though.

Any comments will help me.

Thanks a lot!

* THERM and WINDOW version is 7.6.1

* Section drawing of head and sill is attached below. 

[Robin Mitchell]

One clarification -- you can rotate glazing systems in THERM using the Draw / Rotate / Degree option.

Robin

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Robin Mitchell

Building Technology and Urban Systems Division
Energy Technologies Area
Lawrence Berkeley National Laboratory

[Ventura, Ed Ramir]

What I would do is to import the glass on a separate file, rotate it, copy using locator (shift+F2) and paste it the file I'm working on. repeat for the second glass with the different angle/tilt.

To view this discussion on the web visit https://groups.google.com/d/msgid/LBNL-THERM/CACF39Sv9TP1ycHMcK2t-ZbgBw5Hv7a-tXwm55mthj559%3DiRJow%40mail.gmail.com.

[Robin Mitchell]

Yes I guess the program doesn't support having glass layers at different tilts without rotating them in a different file and then copying/pasting them into the master file, as you suggest. Copying and pasting glazing systems into THERM is not recommended, but I guess in this case you don't have any option, unless as you originally indicated, you want to break the model into two different files. 

Robin 

[D. Charlie Curcija]

We have not tried this before, but it should work if you import in a separate screen and then copy/paste glazing into your original drawing. Same should work to divide model along frame joint and model as two separate THERM drawings and then copy/paste to join them in a single model.

Charlie

On Mon, Jan 11, 2021 at 5:56 PM Robin Mitchell <rdmit...@lbl.gov> wrote:

Any thoughts about how this person should model their system in THERM? 

Robin 

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D. Charlie Curcija, Ph.D.                              Tel: (510) 495-2602

Lawrence Berkeley National Laboratory         Fax: (510) 486-4089

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[Robin Mitchell]

ok, great, thx.

Robin 

[Robin Mitchell]

I conferred with others here and they all agree that this seems like a good approach.

Thanks Ed !

Robin

On Mon, Jan 11, 2021 at 5:39 PM Ventura, Ed Ramir <edramir...@gmail.com> wrote:

[yal...@gmail.com]

Would it be possible to just model the insulating glass in THERM and use the keff (effective conductivity) that is calculated in Window? You wouldn't be able to calculated the system u-factor in Window because of the different angles so might simplify modeling.

[yal...@gmail.com]

Also note that the IGU is underslung. The angle in Window inputs needs to be 135 so that the IGU and air gap and film coefficient is calculated for heat flow downward direction. Below you will see gives you different transmittance. Also you will get lower IGU and frame temperatures due to the underslung angle.

As I mentioned earlier, another method you could take the Gap 1 keff (see below the results) and create material with that conductivity and will be the same. You'll need to get the film coefficient from the Window debug folder which is by default in the following folder:

C:\Users\Public\LBNL\WINDOW7.7\Debug

Some additional up front work needed but probably simpler to model in Therm. Six of one half a dozen of the other.

Best,

Yalin