2011 AIA Convention - Energy Modeling


Energy Modeling: What You Need To Know (EV101)


William Worthen, AIA, Director, Resource Architect for Sustainability
Maurya McClintock, Facade Group
Nicholas Long, NREL.

Session Blurb

This session will present the latest AIA research and efforts related to energy modeling skills and tools, and how you can begin to use energy modeling to assist with high performance project design early in the design process. The outline for the AIA’s Practice Guide on Using Energy Modeling in the Design Process will be presented, as well as other education content and collaborations.



Bill Worthen spoke first. His talk was about the history of energy modeling within architecture, the current state of affairs and some of the challenges facing architects as they try to work with energy professionals and engineers to get better design data. The typical process is late in the project. Usually too late to have significant effect on the design. This is usually to check to make sure the design is going to do what everyone hopes it will do in terms of energy performance, but not to affect real design decisions.

There are certain challenges with this. There are limitations of software such as it may be able to only model certain things. An example given was chilled beams which apparently are difficult to model in current tools. Another issue is that the results are variable. Of course the output is only as good as the input, but the same input in different software can provide different results. This is due to the fact that there is currently no standard for what an energy model is or what energy modeling software does. There are no standards in analysis tools and analysis engines.

To get from 30% to 50% better than ASHRAE 90.1 baseline, design needs to be engaged. Typically, projects can achieve 30% just through tighter engineering of the systems, without really affecting design. To get beyond 30%, the geometry needs to be affected. The challenge is to get architects and engineers speaking a common language. For example, an architect says design and an engineer says geometry, but they both mean the same thing.

The speaker continued by highlighting some information from American Colligate Schools of Architecture (ACSA). It shows that ACSA think that energy analysis is the most important thing that needs to be understood by graduating students but that architecture schools and current curriculum are not prepared and/or not qualified to teach it.

International Green Construction Codes are coming. This is an evolutionary change. Green building codes will force us to do energy modeling.

An energy modeler should be like a spec writer, every project needs one. They might be dedicated on a large project or serving a few smaller projects, they might be internal or external consultant, but they need to be there.

Architects need to understand what is behind energy reports. The underlying assumptions made by energy modelers are unknown to architects. This needs to change.

Next the speaker highlighted some of the related industries activates. First, the ASHRAE presidents term theme: Modeling a Sustainable World. Under development by ASHRAE is a 50% AEDG for Large Hospitals which should be out in May 2012. This is another in the series of AEDG for both 30% and 50% efficiency over ASHRAE 90.1.

Next, the New Building Institute's Outcome-Based Energy Codes (of course there are liability concerns here). How do we ensure owners use the building the way the energy model predicted?

Finally, the AIA is developing a document called Practioner's Guide to Using Energy Modeling in the Design Process. This should help architects understand more about what energy modeling is and means.

The second speaker was Maurya McClintock of the Facade Group. Maurya talked about the tools that are currently available. She highlighted the most common ones including eQUEST, EnergyPlus, IES, EnergyPro (CA) and Comcheck. She also spoke briefly about the ongoing development of a graphical user interface for EnergyPlus and Radiance and the ability to import IFC files into EnergyPlus from Revit.

The next speaker was Nicholas Long from NREL.  NREL develops OpenStudio. He demonstrated this EnergyPlus plug-in for SketchUp. He highlighted the Photo Match feature of SketchUp for getting started quickly in making an energy model of an existing building. He also showed how to quickly turn a SketchUp model used for design into an energy model using a copy/paste method. The demonstration was a very simple box which left me wondering about how well it would work with a well developed model produced by a designer.

In addition, Long spoke about some of the new developments that are being worked on for OpenStudio. These include a basic HVAC graphical design tool, guides and tutorials, gbXML and IFC import to OpenStudio. Finally he talked about the development of a NREL Building Component Library. Components could be customized, configured and saved on the web. Each component would have unique URL so as to be able to share components with others via web hyperlink.

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