Exporting contruction details to Therm

[Anonymous]

Hi everyone,
in order to calculate thermal bridges for Passive Houses, I need to be able to import detail drawings from Archicad into Therm.

From what I understand, Therm (http://windows.lbl.gov/software/therm/therm.html) does not import dwg or dxf files. It only opens its own file type (.thm), or imports "frame" files (.f30 or .f40).

Is there a way I can translate my Archicad drawings into anything like that?

Thanks!

Enrico

[Karl Ottenstein]

I doubt it (pln to thm), but anything is possible with a custom add-on.

Have you looked at the new EcoDesigner for 15? Features here:

http://www.graphisoft.com/products/ecodesigner/

specifically this new feature:

Building model data export to Passivhaus energy calculator
BIM geometry and material property export to PHPP spreadsheet

Maybe that would help if you don't specifically need Therm, of if the Passivhaus group has its own translator to thm...?

Cheers,
Karl

[Anonymous]

Karl, thanks!

I did not know about Ecodesigner becoming compatible with PHPP, this is a huge deal for our company!

Exporting detailed energy info to xls and to PHPP is also a big step to prove that the evaluation issued by Ecodesigner is actually correct (I read somewhere that previous ED accuracy was about 5-8% according to Strusoft, but I could not find any case study with data).

Looks like ED is becoming less of a green toy, and more of a design tool: I cannot wait to receive our AC15 so we can test ED too!

The reason we need Therm is to evaluate potential linear thermal bridges. We need to build construction details to scale 1:5 or similar, to calculate the "psi" value (W/mK) to insert the corrisponding heat losses into the PHPP.

Here's an example from the web (not from Therm): http://www.dartwin.it/wp-content/uploads/mold/step4.jpg

I guess Ecodesigner is still a couple of generation away from giving this kind of results, but we can just wait and hope. The step towards PHPP is already an excellent news.

[Jere]

You can import .dxf into Therm:
http://windows.lbl.gov/software/therm/21a/therm2-chapter5.pdf

[Anonymous]

Great! Thank you!

[Anonymous]

Therm is only 2d and in my opinion it difficult to apply to a building .
Dxf. is imported only as background for make a new hand design . Drawing in therm is painful like in paintbrush.

Therm was developed for windows details fSUA) and has no routines for real architecture . DesignBuilder or Ecotect a very good 3d global building app. and i managed to export from Archicad as gbXML file format one year ago .

A real energy software must have real site climatic charts imported because last 3 years climat changes is big compared to older statistical data. Here you will need Meteonorm app.
You will need a big material database because the biggest problem is the vapour transfer through walls , roofs with minimum alteration of thermal capacity . The catalogue of thermal values are for laboratory perfect condition not for a moisture humid air vapours migrating from your building elements.
The soil - foundations or soil underground levels heat transfer calculations are way more complicated , because non standard soil proprieties and humidity .

So the entire real detailed calculation is futile . Much more important is to have a big picture of projected building with all complex aspects involved .
The real art is to tweak a real value in Ecodesigner for yours building elements .
Real value is a mix of materials , coefficients , and material proportion mixed in your construction elements. For example if a construction is older you will have a depreciation of standard thermal isolation .
The right values can be obtained after some experience . I use only Excel formulas and i say - Therm is beautifull mainly for academic purposes.

[Anonymous]

Archibaldo,
thanks for your contribution to the discussion.

We want to implement the use of Therm (or a similar tool to calculate the psi value for linear thermal bridges) to complete our present workflow.

Our energy efficiency calculation software is the PHPP by the Passivhaus Institut. Version 15 of Ecodesigner is better that any previous one, but we would never use it for any real calculation. Up to 2 months ago (before version 15), we used to define ED as a "toy". With version 15, ED is actually useful because you can use it to export some data into PHPP. As far as data that can be exported, there still a lot of work that can be easily added to the export (I'm guessing, Graphisoft is keeping it for the version 16 update). In my opinion, ED is very far from giving any big picture worth anything.

We are specializing in high energy efficiency and Passive design. If you are familiar with the PHPP calculation spreadsheet, you know how important these thermal bridges are. Even in the "thermal bridge free" design approach, the heat losses caused by a thermal bridge are very important, therefore we want to be able to calculate them.

I strongly disagree with you when you say that the detailed calculation is futile. If you do passive design, you have to desing and calculate all your construction details to maximize energy saving. If you submit your design to be certified by institutes like the Passivhaus Institut or CasaClima, you have to submit your design at 1:20 scale and all your construction details at 1:5 scale (for a single family house, we submitted about 35 details).

[Anonymous]

After import Cad file into Therm it will be used only as background and you have to manualy redraw over this template . The resulted temperature chart is very nice( PROFESSIONAL LOOK ) with colors and temperature isotherm curves and values mixed .

For daily architecture is futile - because more important is the global approach

Not futile for outstanding products and for passive house certification .

Like in the software for structural engineers you cannot think in 2D only , you need 3D finite calculations for real 3D thermal bridges. and this cannot be the 2d - Therm .

You need to have a software made for thermal 3d analysis like aero-spatial , car engine , heat transmission and thermal simulations software's .

No doubt that in 2-3 years a 3d thermal bridges simulation software will unleash the energetic approach of buildings efficiency , an more useful is to have inside a 3d cad software .

Now you have to know allot theory to make a correct calculation . After 2-3 years if a 3d app like ED will take account the 3d mass heat transmission inside thermal bridges , almost every user will make a decent calculation .

The archived sun , and building location - north orientation must be automatic taken into account .

Here in Romania is a very academic approach of passive houses because of
difficult products certification . Therm is recognised in Romania for thermal efficiency product certification but is not easy to use .


Economic problems stopped everything in architecture - in my country .

Energy calculation problem will be resolved by a unitary approach for all Europe inside EURO CODE FOR THERMAL BRIDGES CATALOGUE - good for all countries because today Germany and France measures different the building . Academic Ego .