AEC

BIM and Green Building Studio (1-2-3 Revit Tutorial)

28 Aug, 2008 By: AIA ,Rick Rundell

Architects transform their designs from carbon-positive to carbon-neutral.


Editor's note: This tutorial courtesy of Autodesk.

Since almost half of greenhouse-gas emissions in the United States come from the built environment, it's clear that reducing the carbon footprint of buildings is critical to reversing climate change. The 2030 Challenge and the rise of LEED and other green building certification systems are visible examples of the building industry's commitment to sustainable design.

The ability to perform accurate whole building energy, water, and carbon emission analyses early in the design process is essential for sustainable building design. This month's article explores how the Autodesk Green Building Studio allows architects — the majority of which are not specially trained in any of these analyses — to easily evaluate the carbon "footprint" of a building design emerging from a Revit BIM workflow using the just-released Green Building Studio plug-in for Revit.

Analyzing a Building Design
A computable Revit design model is a great fit for the analyses needed for sustainable design — even during schematic design. As soon as the layout of a building's walls, windows, roofs, floors, and interior partitions (elements that define a building's thermal zones) are established, a Revit model is ready for whole building analyses.

Performing these analyses in a CAD workflow is a fairly difficult undertaking as the CAD model has to be exported and carefully massaged to work with analysis programs. In addition, most analysis software is complex and requires special training — making it unsuitable for casual users like architects or designers. And the output of most analysis programs is complicated, making it hard for architects or designers to understand what to do to improve upon their designs.

Using the Autodesk Green Building Studio Web-based service to analyze building designs from a Revit BIM workflow can simplify this process.

Autodesk Green Building Studio
The Green Building Studio Web service was introduced in 2004 and soon after its initial release, one of my earliest articles in this column featured the Web service. In 2007, its analysis results met ASHRAE Standard 140 and were certified by the U.S. Department of Energy. The service was even awarded the Microsoft Ingenuity Point Award in 2008. Today there are almost 7,000 registered users of the Web service currently accessing energy and carbon results on more than 1,000 active projects.

Built specifically for architects and using gbXML for data exchange across the Internet, the Web service was one of the first engineering analysis tools to deliver interoperability between building designs and sophisticated energy analysis software programs such as DOE-2.

The link between the Revit platform and the Green Building Studio Web service, now an Autodesk product, has been streamlined through a plug-in that enables registered users to access the service directly from their Revit design environment.

Inline Energy Analysis
The Autodesk Green Building Studio Web service enables whole building energy, water, and carbon emission analyses of a Revit building design that can be performed by architects, from within their own design environment, directly over the Internet. This streamlines the entire analysis process and allows architects to get immediate feedback on their design alternatives — making green design more efficient and cost effective.

Based on the building's size, type, and location (which drives electricity and water usage costs), the Web service determines the appropriate material, construction, system, and equipment defaults by using regional building standards and codes to make intelligent assumptions. Using simple drop-down menus, architects can quickly change any of these settings to define specific aspects of their design: a different building orientation, a lower U-value window glazing, or a 4-pipe fan coil HVAC system, for example.

The Web service uses precise hourly weather data, as well as historical rain data, that are accurate to within 9 miles of any given building site. It also uses emission data for every electric power plant in the United States and includes the broad range of variables needed to assess carbon neutrality.

The software determines a building's carbon emissions and the architect views the output in a Web browser, including the estimated energy and cost summaries as well as the building's carbon neutral potential. Architects can then explore design alternatives by updating the settings used by the Web service and rerunning the analysis, and/or revising the building model itself in Revit and then rerunning the analysis.

The output also summarizes the water usage and costs, and electricity and fuel costs; calculates an ENERGY STAR score; estimates photovoltaic and wind energy potential; calculates points towards LEED daylighting credit; and estimates natural ventilation potential. Unlike most analysis output, the Autodesk Green Building Studio report is very easy to understand — giving architects the actionable information they need to make greener design decisions.

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Autodesk Green Building Studio uses the building location to determine the resulting electricity and water usage costs. (Click image for a larger version)

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Registered users can access the Web service directly from their Revit design environment. (Click image for a larger version)

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The Revit user views the output of the analyses in a Web browser, including the estimated energy and carbon emission summaries (shown above) and a detailed LEED water efficiency guide (shown below). (Click image for a larger version)

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Architects can then explore design alternatives by updating the settings used by the Web service and rerunning the analysis, and/or revising the building model itself in Revit and then rerunning the analysis. (Click image for a larger version)

Autodesk Green Building Studio in Action
Van H. Gilbert Architect PC is an architectural firm providing planning, architecture, and interior design services. This 28-person firm, headquartered in Albuquerque, New Mexico, has been using Revit Architecture since 2006. The firm wanted to analyze their Revit designs but had no energy analysis expertise and only a few LEED-accredited architects. So in 2007 they turned to the Green Building Studio Web service, and the firm now uses it on every conceptual design.

"We like the simple user interface and Web-based analysis software of Autodesk Green Building Studio," remarks Stephen Smith, the company's IT director. "It allows even our less technically inclined members of the firm to analyze their designs and make decisions regarding energy usage early in the design process — when it can have the greatest impact — and it prompts early collaboration with our MEP partners as well."

For example, one of the firm's current projects is a new elementary school, being designed as a High Performance (HiP) School in the harsh climate of southern New Mexico. One of the architects on the project began using the service for the first time and, in less than a day, reduced the design's energy use and carbon emissions by nearly 50%. All the architect had to do was submit the Revit design model for analysis, run a baseline analysis, and then try out a few slight design adjustments — selecting the highest possible window glazing rating or increasing the insulation in the south-facing wall, for example. "The results were impressive," exclaims Smith. "It's like taking nearly 30 Hummers off the roads."

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The link between the Revit platform and the Green Building Studio Web service enables designers at Van H. Gilbert Architect PC to analyze their own designs (such as the school building shown here as a thermal model) and make decisions regarding energy usage early in the design process. (Click image for a larger version)

Summary
The design data resulting from a Revit BIM workflow and the whole building energy analysis provided by the Autodesk Green Building Studio Web service work in combination to reduce the cost and time to perform energy modeling and analysis.

This integration enables architects to optimize the energy efficiency of their designs and work toward carbon neutrality earlier in the design process — a key ingredient not only for incorporating energy efficiency into standard building design practices, but also for mitigating the carbon footprint of our built environment.


About the Author: AIA


About the Author: Rick Rundell

Rick Rundell

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