3D thermal Modeling

Lena Javidiani

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Jul 21, 2020, 9:10:30 AM7/21/20

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Hi Everyone,

I am comfortable using Therm7.6, but now i was asked to look into 3D thermal modeling, which program would you suggest? mostly used for curtain wall/glazing systems.

Cheers,

Shin Bakouris

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Sep 14, 2020, 8:12:59 PM9/14/20

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I would like to know the answer to this also.

Shin

yal...@gmail.com

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Sep 17, 2020, 6:11:40 PM9/17/20

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There's many flavors for 3D analysis but none are free. There's standalone heat transfer or multiphysics platforms that have heat transfer solvers. Many are quite pricey $3,000 or more.

There's only one standalone heat transfer software that I know will do 3D radiosity based grey radiation. Others are fixed heat transfer coefficients. If you need grey radiation (not necessary for most problems) then you need to look at multiphyics platforms that are probably $10k plus.

None are plug and play like Therm so will need experience on finite element modeling, meshing, and general concepts in heat transfer.

I use Trisco/Solido developed by Physibel.

Strand 7 also has heat transfer but is primarily a structural FEA and I use in strain problems.

Then there's Ansys, FEMAP, Comsol, etc. multiphysics platforms which are not streamlined for building physics but surely can be used.

roro sell

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Sep 19, 2020, 9:33:48 AM9/19/20

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this document (about 10 years old) of a european program might provide you some leads

http://www.buildup.eu/sites/default/files/content/P198_Software_and_atlases_for_evaluating_thermal_bridges_0.pdf

roro

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Vladimir Pezel

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Sep 19, 2020, 10:19:20 AM9/19/20

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There is also Heat3, for 3D thermal analysis, along with Heat2, for 2D. I think it is getting some traction here in the US.

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Lena Javidiani

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Feb 12, 2021, 4:52:06 PM2/12/21

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Thanks all for the suggestions.

Firstly to mention that the price is not an issue right now as I would like to evaluate the programs first.

Heat3 & Solido are european programs and are not NFRC approved, so I would prefer to keep them as my last options. I did try Solido but was difficult to understand the block concept and the connections to their 2D programs. I preferably would want something as close as possible to Therm but 3D.

Is there any 3D program that would be NFRC approved?

Cheers,

Robin Mitchell

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Feb 12, 2021, 4:58:55 PM2/12/21

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Lena

As far as I know, NFRC does not use (allow?) 3D modeling for their certification program. You might want to contact them to verify this.

Robin

https://groups.google.com/g/LBNL-THERM

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Robin Mitchell

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

yal...@gmail.com

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Feb 13, 2021, 2:34:27 PM2/13/21

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I don't think there is anything in the NFRC technical documents that says you can't do 3D modeling but based on the modeling approach elements that are not continuous (3D effect) are ignored. I suppose that's why NFRC also requires testing for validation. Because 3D is ignored in simulation I don't think there is an NFRC approved 3D software.

It depends on what you are trying to model. Is it a wall? Because Walls don't fall under NFRC.

To compare 3D software need an understanding of what Therm does. The main thing that separates therm is the calculation of air gaps according to ISO 15099. The rest is conduction and non-linear radiation which other FEA also can do. Calculation of air gaps can be done manually by hand or you can write in custom equations for materials in some FE packages. Solido / Trisco and HEAT3 does calculate air gaps according to ISO10077 which will get you close enough. Solido/Trisco also does non-linear radiation at boundaries so there you have it.

I have to add that doing the non-linear radiation for boundary conditions can take hours to solve because of the fine mesh needed for window profiles.

Lena Javidiani

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Feb 23, 2021, 8:32:20 AM2/23/21

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Hi,

Yes that makes total sense, you are right. I will be using Solido. Do you have any videos or trainings on solido? I just have the manual.

Thank you,

Shahima Rahmatipour

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Mar 11, 2022, 12:41:27 PM3/11/22

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Hi,

I am using Solido for 3D thermal modelling. I have seen that you are using this software too.

I am comparing the 3D results with therm and window 2D results. The U-value of whole assembly in 3D is less than the one that I calculated using NFRC method. I expected the worse results in 3D.