EcoDesigner STAR from GRAPHISOFT for energy-efficient building design

The challenge of getting energy evaluations into a building information model has been puzzling developers for a long time now. GRAPHISOFT has offered some energy evaluation capability in its flagship product ArchiCAD, but now the company has announced EcoDesigner STAR to serve highly energy-efficient building design by turning ArchiCAD BIM models into multiple thermal zone Building Energy Models (BEM).

While every copy of ArchiCAD 17 has some aspects of EcoDesigner STAR within it, EcoDesigner STAR itself is an add-on product that offers high end building energy performance simulation and reporting without leaving ArchiCAD.

Miklos Sved, product manager, said that architects can now do low and net-zero energy building design much easier than in the past. EcoDesigner STAR’s standard compliant energy simulation engine, advanced energy model visualization and documentation in addition to the integrated energy simulation functionality, are fully integrated into ArchiCAD. EcoDesigner STAR’s advanced BEM export interfaces (such as gbXML and PHPP) allow full collaboration workflow with building energy consultants and enable data export from ArchiCAD to local building energy code compliance calculation applications.

“The first time it was released, EcoDesigner was an add-on for ArchiCAD and it’s been five years since the first release,” said Sved. “Originally the driver behind the development of EcoDesigner was to integrate BIM and energy evaluation for the early design phase. The other idea was to integrate it into the BIM software environment.”

Sved said they decided to make energy simulation part of their architectural design tool. This was a new approach in those days, but now other companies have also done the same thing.

“The first thing we noticed about energy modeling it’s really complex,” said Sved. “Our original goal was to make a tool that architects could use to optimize their design, and to allow them to be able to make comparative decisions. At that point we didn’t go for detailed analysis because what mattered was ease of use and flexibility. The architect evaluates performance of designs and then changes the design in the early design stage. Then he or she gets the chance to evaluate the project again, and see whether the energy characteristics of the project change for better or for worse because of those changes. This concept allowed us to keep the level of input detail very low. Energy modeling works with thousands of custom input parameters, if you want very accurate simulation results. That kind of controlling of parameters is impossible in the early design phase, therefore we provided many default parameters in the program to keep the workflow fast and simple.”

Meanwhile the early design phase is when the most important design decisions are made regarding energy efficiency, Sved pointed out. GRAPHISOFT created the comparative evaluation tool EcoDesigner for ArchiCAD to address that need. The building geometry and material properties come from the BIM so architects don’t have to recreate the architecture model to build it as an energy model.

A common workflow for analysis is that the architects build a separate model in a third party energy tool. “That’s what happens 90% of the time,” said Sved.
“They only build one model at the end of the design process for documentation and compliance purposes. The optimization doesn’t happen but it should, while it’s still cheap to change, so it’s a problem. Our product grew from that situation and the need for integration.”

GRAPHISOFT had developed this program according to this concept until ArchiCAD 15, in which EcoDesigner was a “very solid modeling energy tool ahead of the singular software solutions offered by other companies at the time.”

Users of the software wanted to be able to go “all the way to compliance documentation level” using this tool. So they asked for EcoDesigner to move up to the next level and wanted it integrated and capable of detailed energy analysis.

On that basis, GRAPHISOFT decided to develop an entirely new technology in terms of building information model conversion into the building energy model.

“The geometry method that we apply inside the software to convert the architecture model to the energy model, is the heart of our technology, but to do it according to ASHRAE regulations we had to rebuild it from ground up,” explained Sved.

This is where the idea of EcoDesigner STAR started more than two years ago. It also signaled the end of the first tool and that EcoDesigner tool was removed from the market. Then they began offering energy evaluation functionality inside every copy of ArchiCAD.

The scope of what is resident in each copy of ArchiCAD is similar to the scope of the first generation EcoDesigner add-on: energy performance evaluation in the early design phases.

EcoDesigner STAR and ArchiCAD’s integrated Energy Evaluation functionality have shared main code but Energy Evaluation only utilizes a part and not the whole energy analysis package. To benefit from the entire package users must purchase an extra license to add on EcoDesigner STAR.

In EcoDesigner STAR the workflow is the same very simple three steps as in Energy Evaluation in ArchiCAD 17: input, calculation, output.

The input contains taking the BIM and taking the geometry and the material property from that model. Certain additional data have to also be put on top of the architectural model to enable a successful simulation because not all the information needed for the energy modeling is included in the architecture model. An example is the climate data file. You have to add that to the ArchiCAD architecture model. “Another type of input you have to assign is an operation profile to each interior space,” said Sved. “This is about the interior comfort requirement. The internal spaces are used as offices and then the office in the U.S. have strict requirements regarding temperature, fresh air, internal humidity, daylighting, etc. These are called ‘comfort requirements.’ They are not part of the architecture model.” Detailed building system parameters describing heaters, coolers and ventilation systems complete the input to the simulation engine.

After all the necessary input are assessed, the energy simulation kernel code executes the hourly time-step energy balance calculation.

The third, final part is when the kernel returns the detailed results which are displayed on the screen, ready for documentation.

If you use EcoDesigner Star you can really build a virtual reality building energy model including complex ventilation, heating and cooling scenarios. In ArchiCAD, the detail level of energy evaluation input is limited and only some basic result information are displayed for documentation.

It is more expensive up front to design a sustainable “green” building, so if you want to do it right you are going to have to do it from the early design phase, said Sved. You must keep in mind in everything you do you’re going for low energy and sustainable design.

From GRAPHISOFT’s website:

Comparing Energy Evaluation and EcoDesigner STAR

Tags: AEC, Archicad, architecture, BIM, EcoDesigner STAR, Graphisoft

Categories: AEC, Archicad, architecture, BIM, building information modeling

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