BIM Energy Analysis with ArchiCAD 16
Graphisoft has just released the preview videos for their new ArchiCAD version 16, and we are pretty excited about it here at Emu Architects. Enrico Bonilauri has written an extensive assessment of the newly integrated energy analysis features (basically incorporating EcoDesigner) over on our Italian blog. I’ll attempt to translate his thoughts into English here for our international readers:
On the Graphisoft website you can view the entire ArchiCAD 16 presentation, including many new design tools, integration with a cloud based BIM components library and ‘openBIM‘, as well as many other new features that will improve productivity for users.
All of that aside, the one feature that most impresses us is the integration of energy modeling into the main software, absorbing and expanding dramatically the characteristics of the former add-on, EcoDesigner. This sort of innovation turns over a new leaf in the world of BIM. In our opinion, this change represents the most significant step taken by this software house since version 12 and demonstrates how ArchiCAD BIM software is becoming more and more suitable for designers of energy efficient buildings and passive houses. This is not to say that the energy analysis given by ArchiCAD would be able to replace programs such as PHPP, but it does demonstrate that BIM can allow for a series of tests to be performed in the preliminary design phase that can dramatically help steer a project in the direction of the passive standard in later phases.
Let’s look at some of the details…
What we LIKE about the integrated energy analysis in ArchiCAD 16:
First of all, ArchiCAD absorbs EcoDesigner. EcoDesigner was an add-on introduced for ArchiCAD 13 and later versions. In the past we have not given great reviews to that add-on; we evaluated the first two versions (for ArchiCAD 13 and 14) as basically a simple toy with questionable ability to create accurate data. With version 15, EcoDesigner brought some utility with it in allowing a direct export of thermal envelope data to PHPP software. And now, with version 16, it seems that EcoDesigner’s features have been absorbed within ArchiCAD and have been greatly expanded.
Regarding the accuracy of the energy analysis, perhaps the most important improvement with version 16 is the ability to import data from professional climate analysis software, such as Meteonorm (in TMY3 format). This may seem rather insignificant, but in fact makes a fundamental difference for preliminary designs of passive houses. Also, once you import the local climate data, you can customize the wind rose, allowing for site-specific levels and directions of wind exposure.
It is also now possible to insert custom usage profiles on an hourly basis, allowing you to enter extremely accurate data about the needs of the building in terms of comfort, energy, and specific loads (internal heat gains).
Accurate climatic data and precise energy loads are the two most important advancements made by version 16 of ArchiCAD’s energy analysis module – it is no longer a toy.
As far as exporting to PHPP, the option remains, but it is unclear whether or not the functionality was extended to allow customization of the range of data that you can export. In version 15 of EcoDesigner, which we tested last year, you could very easily export data such as areas, layered elements of opaque structures (and their transmittance values), as well as size and orientation of windows. The export was relatively easy and straightforward, and the data were accurate and consistent with the model. Furthermore, when changes were made in the BIM model, it was possible to export the updated data without losing the other entries.
Another very important aspect of the new ArchiCAD 16 is the possibility to assign physical properties to the fills. Specifically, it is now possible to enter values of thermal conductivity, density and heat capacity. For those who frequently deal with detailed energy management, this little addition can help to notably speed up your work. As far as the windows, ArchiCAD 16 also contains several new library elements such as glazing, frames, thermal bridges, etc… all fully customizable.
As far as the boundary conditions of structures, which are fundamental for a detailed energy analysis, ArchiCAD 16 allows for the automatic recognition of the position of each structural element within the thermal envelope (to determine the direction of heat flow and to associate the correct surface resistance). Moreover, for ground level elements, the program can automatically distinguish between underground parts and exposed parts. Again, these details show that this version of the preliminary energy analysis software is no longer a toy.
What we DO NOT UNDERSTAND about the integrated energy analysis in ArchiCAD 16:
There are some aspects of ArchiCAD 16 whic are not explained in the video presentations.
The first thing missing, which is a fairly large mistake on the part of Graphisoft, is that none of the 23 presentation videos show the types of output that can be achieved regarding preliminary energy analysis. Perhaps the output will similar to that in EcoDesigner 15? We don’t know.
A second point that is not clear concerns the calculation of dispersion surfaces: it is unclear of the measurements are taken from the interior or the exterior of the elements. This may seem like a rather irrelevant detail, unimportant for the energy efficiency of a building. However, in practice a convention is followed, especially for passive house design: it is up to those who perform the energy calculation to chose whether to use internal or external measurements, but it’s important to stay consistent from beginning to end. For those planning passive houses in Italy, by convention we always calculate the outer dimensions of the building’s elements (in other words, everything you can see from outside). This is of particular importance because it also determines how to calculate thermal bridges (PSI) in finite element programs. In EcoDesigner 15, the entire building element was exported to PHPP (walls, floors, etc), so it was possible to chose between internal or external measurements by modeling in ArchiCAD accordingly. It’s not clear if this is still possible in ArchiCAD 16, but can be a real deal breaker for the usability of the tool for the correct workflow in passive design.
Lastly, it would interesting to verify the calculations for transmittance values of elements dispersing towards the ground.
What we DO NOT LIKE about the integrated energy analysis in ArchiCAD 16:
Now for the flaws that we have found, based on the video presentations of the integrated energy analysis in ArchiCAD 16:
First of all, the section of the presentation dedicated to energy analysis is entitled “Green”. If ArchiCAD wants to be seen as a serious energy analysis software, this must change. Call it “energy”, “environment” or something similar. With all the garbage that is being generated in the name of “green” (greenwashing), this makes the new version of ArchiCAD seem much more commercial and less credible than it really is.
ArchiCAD 16 absorbs and greatly improves EcoDesigner, but it does not solve all the problems that the former add-on brought with it.
For example, there is no mention of the margin of error for the energy analysis calculations. We found no reliable calculations to validate the results of EcoDesigner 13, 14, and 15 (the StruSoft software that takes care of the energy modeling component in ArchiCAD claims a 5-8% margin of error). If Graphisoft wants to get serious and proceed in this new direction they have taken, they will need to publish these comparative analyzes. We intend to test out this new software alongside a parallel test in PHPP, and we’ll make sure to publish the results here on our blog in the coming months.
Another thing is that ArchiCAD 16 inherits the somewhat superficial attitude that EcoDesigner had towards assigning shading standard values to openings. Sure, now you can customize the degree of shading for each opening, but you can only chose between three options: no shade, partial shade, and full shade. If you consider that you can make detailed calculations with software such as Ecotect, we would propose that ArchiCAD not limit itself to this superficial mode of calculation.
Another quick note: thermal bridges, thermal bridges, thermal bridges. A BIM software must be able to automatically recognize thermal bridges of a building, whether they be geometric or structural.
Furthermore, the interface itself for the energy analysis portion on ArchiCAD 16 seems to have forgotten the fact that Graphisoft actually makes an add-on dedicated to building services: it’s called the MEP modeler.
It seems odd that EcoDesigner didn’t include some sort of integration with this add-on previously, and with this new version it has remained an oversight.
There are a few other basic elements for energy evaluation that are missing, such as emissivity of building element surfaces. Values like periodic thermal transmittance , phase shift and attenuation , or even verification of interstitial condensation (Glaser) will have to be added to future version of Archicad.
Finally, if you can assign fills to physical properties, then you probably should be able to associate other values, such as resistance to vapor diffusion or embodied energy value. This would greatly increase the value and significance of the energy analysis tool.
The length of this post alone should demonstrate the importance of this fundamental step to integrate energy analysis into the ArchiCAD software. This is significant news for us users.
Now that the main software has absorbed the EcoDesigner add-on and included the possibility to import detailed climate data from Meteonorm, we expect ArchiCAD 16′s ability to create a preliminary energy analysis to be much more reliable. The fact that energy design has now been pushed inside the BIM framework to the actual assignment of physical properties of materials, means that the export of energy balance results to cutting-edge softwares (such as PHPP) can become the future workflow for the design of highly energy efficient and passive buildings.
Based on the videos published by Graphisoft, it’s unclear as to what the format is for the energy analysis output. There are also a few other obscure aspects that should be further tested before we can conclusively comment on them.
As far as the accuracy and reliability of the preliminary results of the energy analysis, StruSoft’s stated margin of error should still be tested. Those results need to be transparently published before ArchiCAD can be taken seriously as an energy analysis tool.
All in all, ArchiCAD 16, as presented in the series of videos on Graphisoft’s site, shows considerable improvement and potential, while leaving ample room for modifications in future versions.