Mats wrote:
I would like to comment about gbXML and GBS!
First data needed for energy analysis!
For Green Design this is in my opinion a absolute MUST.
When we have to calculate buildings with thicker insulation and higher energy saving standards or calculate natural ventilation or natural cooling then gbXML simply wont do. It have to many holes regarding things like infiltration and heat recovery. For Nordic condition gbXML was never an option.
Your terminology is a bit confused here:
- - GBS is a company providing an online analysis service;
- gbXML is a file format
GBS uses gbXML as a transport mechanism for building data, but they are otherwise unrelated. IES, Ecotect, Trane, and many others are also using gbXML as a transport mechanism, and CAD vendors like Autodesk and Bentley have acknowledged that fact by incorporating gbXML connectivity into their products.
As such, your observations relate entirely to GBS. To say that gbXML isn't suitable for certain calculations is like saying a .pln isn't suitable for producing a new drawing - you don't produce things with a file format. gbXML is explicitly designed for transporting the kind of data you're talking about and - better still - it's an open, published standard with contributors from across the industry.
Mats wrote:
ED main goal is to mix simplicity and speed to let Architects make informed and accurate decisions for green design integrated in their design process.
ED is an entirely different exercise. Real building simulation across an entire year of use is very computationally intensive - much like the calculations performed for radiosity rendering, only more involved because the model parameters change on an hourly basis as you move through the days and seasons. This is why the GBS analysis can take a long time (as any genuine simulation engine will). It may not be helpful to do this at a very early stage of design (presenting ideas to the client) when you may not have established the construction of the building fabric. All you want is 'rule of thumb' results - how is performance affected if I do this? Or that? Is my design improved or worsened? For example, our local planners were leaning on me to re-orientate a building to align with the road rather than the sun - a difference of 15 degrees. I would have very much liked to be able to quickly establish how damaging that might be to solar gains etc. I'm hoping that's what ED will deliver.
The data produced by ED may be wildly inaccurate in a literal sense, but should help you make decisions at an early stage in order to produce an excellent foundation for fine-tuning later, when the early decision have been frozen and detailed design begins. This is where more powerful tools become involved (e.g. IES), and gbXML is the emerging standard for sharing data with them.
Ralph Wessel BArch
Noemi Balogh
