Sustainable Design Tools Exhibited at AIA 2009

The area of sustainable design tools showed a lot of momentum at this year’s AIA Expo with the introduction of several new products. Graphisoft finally made the vision of “one-click evaluation” a reality with its new EcoDesigner application that is fully integrated within ArchiCAD, making early stage design analysis very easy for ArchiCAD users. Bentley used the show to highlight its new detailed building analysis tools, Hevacomp and Tas. IES, the leading vendor in the performance analysis field, introduced a new application, VE-Gaia, to add to its already substantial product repertoire. Another new analysis product that I came across at the AIA Expo was DesignBuilder, originally developed in the UK and just starting to be marketed in the US. Last but not the least, there was Autodesk, which showed the 2010 version of its re-branded Ecotect Analysis application, following up on its Ecotect acquisition last year. An overview of all these applications is provided in this article. It follows up on the earlier articles on the technology product highlights from the AIA 2009 Convention and the separate overview of the financial and business management applications, both of which were published a few weeks ago.

Graphisoft EcoDesigner

One of the most significant announcements related to sustainable design at the AIA show this year came from Graphisoft, which launched a new energy evaluation tool, EcoDesigner, that works inside of ArchiCAD. It is the only analysis application so far that is fully integrated within a BIM application, allowing ArchiCAD users an easy way to analyze the energy performance of a proposed building design in the earliest design phases, when the most critical decisions that influence energy performance are made. Designed to be comprehensive, yet quick and easy to use, EcoDesigner calculates the energy consumption, carbon footprint and monthly energy balance of a proposed design, enabling architects to efficiently evaluate multiple design alternatives and find the optimal one from a sustainable design perspective. They can fine-tune aspects such as building orientation, building volumes, area and orientation of glazed surfaces, and shading options, all of which can greatly impact energy performance.

The use of EcoDesigner involves three main steps: model analysis, energy calculation, and display of results. The first time EcoDesigner is launched for a project in ArchiCAD, it runs through an automated model analysis that breaks the model up into structure groups based on which the energy calculations can be performed. A Model Review palette allows these structure groups to be displayed in specific colors on the floor plans and in 3D for visual review, and to make any necessary changes to the groups (see Figure 1). The next step is to define various other energy-related settings for the project such as its geographical location, building type and function, orientation, wind protection, and solar reflection, façade shadings of the different orientations, and information about the MEP system such as ventilation type, air-to-air energy recovery system info, heat pump characteristics, etc. Some settings such as the thermal properties of structural elements and openings are automatically calculated based on their type, but these can be manually changed or selected from product catalogs that are integrated with the application. It is also possible to specify the local prices for the purchased energy sources, which will enable the carbon footprint to be calculated.

Once all necessary input data is provided, clicking on the Start Evaluation button starts the analysis process. EcoDesigner uses an accurate dynamic calculation algorithm that evaluates heat transmission of the building envelope structures at every hour of the day throughout the year. It uses a well-established and certified energy calculation engine, VIPCore developed by StruSoft. EcoDesigner’s energy calculations have been validated by finding that they are within 7-8% of the results achieved by using more detailed and sophisticated analysis tools, thereby assuring users of their reliability. The analysis results are displayed in three sections as shown in Figure 2: annual energy consumption according to consumption type (heating, cooling, lighting, usage) and prime energy usage (gas, oil, coal, electricity, etc.); the carbon dioxide emissions resulting from the building's operation over the course of a year; and the monthly energy balance contrasting the amount of energy the building emits with the amount of energy it absorbs from the environment and its own internal heat sources.

While the energy analysis capability provided by EcoDesigner is not revolutionary in itself, what is significant is that it is integrated within ArchiCAD, bringing the “one-click evaluation” vision for BIM to reality at last. Architects can now perform a quick energy estimate even on complex projects, without being a building energy expert, and without leaving their BIM application. The introduction of EcoDesigner should certainly help to heighten ArchiCAD’s appeal as a BIM application and strengthen its position in the industry.

Autodesk Ecotect Analysis 2010

Even prior to its acquisition by Autodesk last year, Ecotect was one of the most popular analysis tools among architects, specifically developed for them to be able to assess aspects such as solar exposure, thermal performance, acoustics, lighting, shading, etc., during schematic design as well as design development. An introduction to the basic principles of the application and how to use it was published in AECbytes in November 2007—it specifically focused on demonstrating how useful Ecotect could be in the early stages of the design process. After its acquisition, Ecotect has been rebranded as Autodesk Ecotect Analysis and the 2010 version of the application was recently released. It was demonstrated at the AIA by Autodesk, along with Green Building Studio, another analysis application that had Autodesk acquired. The two are now being marketed as complementary products. Ecotect customers who add subscription to their software license are given access to the Autodesk Green Building Studio web-based service for the duration of their subscription and can use it to evaluate multiple design alternatives for energy efficiency and carbon neutrality.

The new Ecotect Analysis includes an expanded array of environmental analysis and simulation capabilities including shadows and reflections, shading design, solar analysis, photovoltaic array sizing and load matching, lighting design, right-to-light analysis for neighboring buildings, acoustic analysis, thermal analysis, and ventilation and airflow. An example of solar analysis in Ecotect is shown in Figure 3-a, where a freeform façade is being analyzed for solar radiation exposure so to determine the optimal shape for minimizing direct solar gains. Another example is shown in Figure 3-b, where the daylight factors and illuminance levels are calculated and used to design a space to maximize the use of daylighting. Other examples include shading design analysis, shown in Figure 3-c and ventilation and airflow analysis, shown in Figure 3-d.

One of the key strengths of the application is the easy-to-use interface and, as demonstrated by the images above, its visual communication tools that display analysis and simulation results in ways that can be easily understood by architects and demonstrated to clients. It also has some generative design capability, which can be seen in its Right-to-Light analysis, demonstrated in Figure 4. It provides the designer with an optimal envelope within which the form of the building should stay to satisfy the right-to-light of neighboring buildings (the ones with the blue windows).

Ecotect continues to rely on the gbXML format to get model data from BIM applications such as Revit Architecture, ArchiCAD, and Bentley Architecture, and is thus not that closely tied to Autodesk solutions yet. Over time, however, it is possible that Autodesk will build API-level integration between Ecotect and Revit, allowing Ecotect to not only provide “one-click evaluation” for Revit users—similar to what the new Graphisoft EcoDesigner provides for ArchiCAD users—but go beyond it to provide bi-directional integration—where a change made to the model in Ecotect can be brought back automatically into Revit. This level of seamless integration is really what we need for sustainable design analysis to become a fundamental component of the design process.

VE-Gaia from IES

I first wrote about IES’s building performance solutions in my article on Autodesk University 2006, where the company was exhibiting its sophisticated and comprehensive building performance software suite <VE>, short for “Virtual Environment.” At that time, the application had direct API-level integration only with Revit MEP, and was seen as a high-end application that could be used primarily by energy experts and MEP engineers for detailed building analysis and energy code compliance at the later design stages. Since then, IES has greatly diversified the array and scope of its applications. At the AIA show last year, it launched VE-Ware, a free building energy and carbon assessment tool that can be accessed by plug-ins to either SketchUp or Revit.  It works with the building geometry as input and uses international data on climatic conditions and the typical characteristics of different building, room and system types to provide feedback on the building’s energy consumption and carbon dioxide emissions, and also compares the results to the Architecture 2030 Challenge targets in North America. Then at Autodesk University 2008, IES released the VE-Toolkits, which are stripped-down versions of <VE> intended specifically to be used by architects for early design decisions and quick iterative assessments. They include tools for analyzing energy consumption, carbon emissions, LEED daylighting, solar shading and artificial lighting, and are integrated around a central 3D model that can connect directly with SketchUp, Revit, and with other 3D design tools via the gbXML format (see Figure 5).

At the AIA show, IES introduced an additional tool in its product suite called VE-Gaia, whose capabilities lie between the VE-Toolkits and the full-fledged <VE> application, now labeled VE-Pro (see Figure 5). It is intended to allow designers to undertake complex environmental performance analysis but without the need for expert knowledge that the full-fledged VE-Pro product requires, thereby opening up sustainable design analysis opportunities to a wider range of users. It offers the same ease of use and quick feedback capabilities as the VE-Toolkits, but also provides users the ability to input exact building data and manipulate models. It features “step-by-step” smart navigation that includes analysis workflows for varied sustainable design tasks such as climate review, availability of natural resources, building metrics, materials use, water usage, energy/carbon, daylighting/solar, renewable/low carbon technologies, occupant comfort, passive design strategies, and others (see Figure 6). Additional functionality such as LEED compliance and urban design analysis are also available as add-ons to the base product. Plug-ins for Revit and SketchUp, plus tight gbXML connectivity to ArchiCAD allows models to be imported directly without the need to re-build.  Independent model building and gbXML/DXF import capabilities are also available. VE-Gaia is expected to be released later this month.

Bentley’s Tas and Hevacomp

Bentley has been continuing to expand its portfolio of solutions for building design, as described in my article on its V8i launch event last November. In addition to its multi-disciplinary suite of BIM applications, GenerativeComponents, structural analysis tools, and model checking and collaboration solutions, it now offers two energy analysis tools, Tas and Hevacomp, that are packaged into the “Energy Performance Series.” The Hevacomp product was acquired by Bentley last year; Tas, on the other hand, is developed by Environmental Design Solutions Limited (ESDL) and Bentley has acquired exclusive distribution rights for it. Both these applications are well established for energy design, analysis, and simulation in the UK, which has very strict energy standards for buildings, and they have been used in several high performance green buildings, including the iconic 30 St Mary Axe, Heron Tower, Terminal 5 Heathrow, 122 Leadenhall Street, and CityPoint, London (see Figure 7). Bentley is hoping to now popularize these applications in the US and Canada as well, and made them a focal point of its demonstrations and exhibits at the AIA show.

In addition to Tas and Hevacomp (fully labeled as Bentley Tas Simulator and Hevacomp Simulator respectively), the Energy Performance Series also includes a third application, Hevacomp Mechanical Designer. The two Hevacomp applications are more focused on MEP engineering and allow the energy dynamics of a building to be studied in conjunction with detailed models of its mechanical systems. They use EnergyPlus as their analysis engine, which is optimized for typical project configurations and to ensure compliance with regulatory requirements and industry best practices, and are best suited for small to medium-size projects. Tas Simulator, on the other hand, can be used by engineers as well architects and energy consultants to better understand and accurately predict the energy consumption, CO2 emissions, operating costs, and occupant comfort of buildings. It has its own proprietary high-speed analysis engine, which is capable of performing dynamic thermal simulation for large and complex buildings and allows users to perform analyses more frequently, in sync with the design process. Both Hevacomp and Tas simulations can also be used in tandem for additional insight and complementary in-depth studies, supporting iterative design refinement through timely and actionable analyses results.  

Similar to other energy tools, Bentley’s applications can get building data from CAD and BIM applications through the gbXML format, allowing model data to be re-used rather than needing to be re-created. However, Bentley sees its applications as having a competitive edge by providing fast, powerful, and accurate dynamic simulation for building load, plant energy, passive design, and thermal simulations, enabling users to perform a complete and in-depth analysis of a building’s architecture and critical systems by considering the interrelationships between multiple systems and aspects of design. They also support the widest variety of energy standards including ASHRAE Standard 90.1-2004, ASHRAE Standard 140-2004 (BESTEST Models), LEED Energy and Atmosphere Credit 1, U.K. Building Regulations Part L2, ISO, ANSI/ASME, CIBSE, and others, facilitating required compliance checking and documentation. Evidently, both Tas and Hevacomp are more suited to detailed building analysis, putting them in the category of IES’s VE-Pro rather than in the category of early-stage design analysis tools such as VE-Gaia, Graphisoft EcoDesigner, or Autodesk Ecotect Analysis.

DesignBuilder

And finally, I also came across a new energy analysis tool at the AIA show called DesignBuilder, which uses the EnergyPlus simulation engine and is targeted for use at all stages of building design. Originally developed in the UK, it is now starting to be marketed in the US and Canada. It has its own modeling interface, which allows building models to be assembled by positioning blocks in 3D space and cutting and stretching them to model the specific building geometry. Blocks can be partitioned into energy zones for calculations. A new release of the application includes gbXML import capabilities, allowing models to be brought in directly from BIM applications for analysis rather than be re-modeled within the application. The DesignBuilder gbXML import process includes advanced healing algorithms that allow missing, misformed and misaligned CAD surfaces to be corrected. Shading surfaces can be imported as well as standard construction surfaces like walls, windows, roofs, floors, doors, etc.

The analysis capabilities of DesgnBuilder include calculating building energy use, evaluating façade options for overheating and visual appearance, visualization of site layouts and solar shading, thermal simulation of naturally ventilated buildings (see Figure 8), daylighting and lighting control systems, and calculating heating and cooling equipment sizes. Recent enhancements to the application include 3-D Computational Fluid Dynamics (CFD) that allow analysis of the airflow and comfort distribution inside and outside of buildings, mixed mode natural ventilation to ensure that HVAC and natural ventilation do not occur simultaneously, new HVAC modeling options including humidity control and baseboard heaters (convective and radiant), the option to include/exclude zones from the analysis so that it can be focused on specific parts of a building only, display of simulation results for individual surfaces and openings, green roofs including irrigation control, the option for radiosity-based daylight simulation integrated within the EnergyPlus thermal simulation, and parametric cooling design calculations and simulations.

Conclusions

The increase in the number of analysis tools is a testament to the increasing importance of sustainable design in architecture and the need to optimize building performance. Unlike in the past, when performance analysis was primarily the purview of energy experts, academics, and research institutions, they are now becoming a part of the mainstream architectural toolset, with interfaces that non-technical people can also easily use and understand. Of course, the maxim of “garbage in, garbage out” very much holds true for sustainable design tools as well, and it is easy to be seduced by the colorful diagrams and charts and omit to question the veracity of the input and the accuracy of the output. It’s terrific that we have finally reached the point where the input of building geometry to the analysis tool directly from a BIM application has become a commonplace feature—but we have to keep in mind that geometry is only one of the inputs, and that an accurate analysis depends upon a whole host of other input data that has to be specified correctly as well. It is here that the experiences and insights of an energy expert come in and play a critical role in the design of sustainable buildings. Thus, while it is great to have the tools with their ever-increasing capabilities, it is important to not forget the human element that is ultimately needed for the creation of successful sustainable architecture.

About the Author

Lachmi Khemlani is founder and editor of AECbytes. She has a Ph.D. in Architecture from UC Berkeley, specializing in intelligent building modeling, and consults and writes on AEC technology. She can be reached at lachmi@aecbytes.com.

Features > Sustainable Design Tools Exhibited at AIA 2009 > Printer-friendly format