"Ask a Modeler" Column Archive

10-20-2020: Are There Strategies to Save Cost and Energy by Changing the way HVAC Load is Calculated?

Volkan Doda, Associate Environmental Designer at Atelier Ten, replies: "Dear Right Size, Rejoice, as gone are the days of boasting about the biggest kit in town. Now is the time of the kit that is just the right size to do the right job right. It’s obvious: good engineering strives for a working solution with ever higher efficiency by designing out waste. Coincidentally, not paying for waste also tends to make things cheaper. Great, but what’s the right size then, I hear you ask, and this is indeed where things get murky..."

09-15-2020: Should the Modeling Community Focus More on Existing Buildings to Battle Climate Change?





Alex Nutkiewicz, M.S., PhD Candidate at the Stanford Urban Informatics Lab, replies: "As many readers might agree, buildings are a critical component of a sustainable, low-carbon future. In 2019, 28% of all primary energy consumption (and subsequent carbon emissions) in the United States came from our buildings (International Energy Agency). And while there are emerging policies that emphasize the importance of energy efficiency in newly constructed buildings (California Public Utilities Commission)..."

08-19-2020: What are Some New or Creative Sources of Hard-to-Get Data?

Rhys Goldstein, Principal Research Scientist at Autodesk Research, replies: "Dear Playing, I’m happy to suggest a few “creative” sources of data for you to play with. You’ll have to judge whether they’re appropriate for your work! Let’s start with occupancy schedules. Suppose we want to derive them from the behavioral patterns that occur in an existing building. Our first instinct may be to explore the various technological solutions at our disposal... Sometimes the simplest solutions are the best..."

07-21-2020: Are There Any Aspects of Buildings That Current Simulation Tools Do Not or Cannot Address?

David Goldwasser, Software Developer and Researcher at NREL - Buildings and Thermal Sciences Center, replies: "Dear Testing, The short answers are yes and yes, which is why whole building simulation engines and modeling tools are continually evolving. When developers consider adding a new functionality, they perform a balancing act of the impact of a building characteristic or element on consumption, equipment sizing, comfort, and safety against the cost and complexity of implementing, modeling, and simulating that building characteristic or element..."

06-16-2020: How Well do Building Simulation Programs Model Thermal Bridging?

Som S. Shrestha, R&D Staff Scientist at Oak Ridge National Laboratory, replies: "Dear Learning, Building envelopes are non-homogeneous, so heat transfer through a building envelope is not one dimensional due to thermal bridging. However, thermal bridges cannot be explicitly modeled in most whole-building simulation tools, including EnergyPlus. Therefore, modelers need to somehow account for the impact of thermal bridging in their building models..."

05-19-2020: When is the Earliest in the Design Process That Useful Performance Simulation is Possible?

Eric Flower, Software Account Executive at Willdan, replies: "Dear Early Bird, Where did the time go? Design evolves at such a fast pace that decisions must often be made based on partial knowledge. Because the design process is dynamic, every stage of the process presents its own unique opportunities for 'early moments'..."

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04-21-2020: What Questions Do You Ask When Doing Sanity Checks on a Model?

David Eldridge, Energy Efficiency Ninja at Grumman/Butkus Associates, replies: "Dear Sanity, Where did you go? Sanity seems to be out the window these days. But if you feel like you are losing it while working from home, at least your modeling results don’t have to be a contributor..."

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03-30-2020: What is the Biggest Misconception Designers Have About Energy Modeling?

Sara Motamedi, Senior Building Performance Analyst at Interface Engineering, replies: "Energy modeling provides us an insight about the importance of design decisions on total energy consumption. On one hand, I’ve seen architects who are eagerly waiting for the energy modeling results..."

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02-18-2020: How is the BEM Industry Changing to Meet the Challenge of Mandatory Energy Codes?

Krishnan Gowri, Building Performance Practice Lead at Intertek, replies: "Challenge comes along with the tremendous growth we are experiencing to meet the simulation and modeling needs of the design community..."

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11-19-2019: What is the Future of Energy Modeling Going to Look Like for the Industry?

Michael Wetter, Staff Scientist at Lawrence Berkeley National Laboratory, replies: "The future of energy modeling will be similar to the present of energy modeling—EnergyPlus is not going away..."

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10-16-2019: What are Some Alternative Careers that use Building Energy Modeling Skills?

Stephanie Egger, Product Manager at AMS, replies: "Speaking as a former building energy modeler myself, I’ve come to learn that one of the (many) great things about energy modeling is that the core skill set is highly transferable!"

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09-17-2019: How Are Energy Modeling Careers Evolving?

Carrie Brown, Senior Technical Consultant at Resource Refocus, replies: "I’m reasonably certain that we’ll continue to have buildings in the next few decades -- and if we don’t, the future of energy modeling careers probably won’t be our top concern..."

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07-23-2019: How Can I Talk to Clients About the Uncertainty in Models?

Michael Sweeney, Energy Engineer at AKF Engineers, replies: "My first instinct is to recommend that you bang loudly on your client’s desk while shouting the aphorism (generally attributed to the statistician George Box), ‘ALL MODELS ARE WRONG BUT SOME ARE USEFUL!!!!!"

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06-19-2019: How Do You Get People Excited About Building Energy Modeling?

Dan Macumber, Engineer with NREL Commercial Buildings, replies: "This question really caught me by surprise, I mean who does not get excited by heat pumps, they are practically engineering magic!"

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05-22-2019: What is the one thing no one tells you about building performance modeling?

Erik Kolderup, Principal at Kolderup Consulting, replies: "Dear Wondering, Only one thing? Many are the unspoken secrets of the ancient modelers! But here’s one...

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