We took part in the webinar “Green” BIM – Low Energy Building Design for New Projects and Retrofits with GRAPHISOFT EcoDesigner”, organized by Graphisoft to present Ecodesigner, the energy evaluation add-on for ArchiCad.
ECODESIGNER FOR ARCHICAD
Ecodesigner is an add-on issued by Graphisoft for ArchiCad. It allows architects to evaluate the consequences of early design decisions on the energy and environmental performances of their designs. This lightweight and fast software gives a fairly comprehensive picture of the overall energy requirements of buildings while still working within ArchiCad.
The webinar pretty much followed the product presentation that was already available online on Graphisoft website, with two Passive Houses being used as case studies. With these two examples, the presenter demonstrated the use of EcoDesigner. He could work on the energy performance of those buildings while still at the preliminary stage of architectural design, before HVAC and energy consultants would step into the project.
PROS AND CONS
The two strong points of EcoDesigner are its ease of use and speed. The product target audience is architects who are in charge of preliminary and architectural design. These designers are now able to quickly evaluate the energy performance of their buildings without stepping foot into special fields such as building services or full energy modeling. We had a chance to test the free demo version of EcoDesigner (download it for free here). We can say that this program can deliver what it promises.
As it is easy to understand, this simple tool can end up giving over-simplified results. EcoDesigner is capable of automatically recognizing envelope element structures that have been set in ArchiCad, opening types etc. Unfortunately, the program is not yet capable of recognizing the geometry of the facades of the building (a real shame for a BIM software), so that building and opening shading has to be manually set within a few standardized options.
One more missing detail is thermal bridges. It is possible to force them into the calculation by overriding the calculated thermal transmittance of envelope structures. Needless to say, this slows down the speed of the process immensely.
The calculation output of EcoDesigner is a PDF report that shows the overall monthly energy requirement of the building(s), including HVAC, lighting and other uses. The result is given both in Watts per square meter (W/m2) and as Carbon Footprint.
We did not dare to take a look at the algorithms of the software, which are based on the VIP-Energy by Strusoft. The error margin declared by the software house is between 5 and 8%: as an early stage tool that is not meant for ant kind of certification, this magnitude of error can be acceptable.
Just like ArchiCad, EcoDesigner allows for customization of materials and building elements to be used for the calculation. The software is also able to associate the physical properties of a construction material with the relative fill in composite structures.
Our experience with ArchiCad is that this kind of BIM software needs a lot of time to get started with the first few projects (much more than what their software houses want us to believe). Once all default company settings and databases are set and ready, the work flow is easy, quick and reliable, and the output is better and requires less time than traditional CAD programs.
We managed to test the EcoDesigner database: it’s relatively easy to customize construction materials and elements such as doors and windows. Our advice is to set up your own database entirely, since the physical values of the materials of the default database may not be that accurate.
ECODESIGNER: FUTURE DEVELOPMENT
The presenter announced that next version of EcoDesigner will follow ASHRAE 90.1 guidelines for LEED Certification, and the equivalent for the Australian GreenStar, also allowing for multi-zone calculation.
As far as daylight study, however, it looks like next release of EcoDesigner will not include this feature, as the built-in rendering engine of ArchiCad does not seem to be capable to carry out the necessary calculation to yield reliable results.