Phius Project Certifier Al Mitchell reflects on his experience at the 2023 ASHRAE Building Performance Analysis Conference in Austin, Texas.
Last week, I had the privilege of attending and presenting at the 2023 ASHRAE Building Performance Analysis Conference (BPAC) in Austin, Texas. As far as conferences go, the annual building performance simulation conference is my second favorite, closely following the acclaimed (and quickly approaching) PhiusCon, despite being two very different events.
BPAC has a different scope, and is mostly focused on the simulation aspects of building design, from tool and workflow development to application of the analysis to the presentation of results. Built upon this foundation, there are usually a few key themes that penetrate the sessions, and for 2023 I would identify these as: decarbonization, resilience and educating the next generation.
The discussion on resilience and decarbonization are close to the Phius mission, and are the two backbones of the forthcoming Phius REVIVE 2024 retrofit program.
For resilience, most of the presentations examined the strain of future climate conditions and extreme climate periods and their impact on the building mechanical systems. When the temperature outside is beyond the statistical design temperatures used to size a building’s equipment, the systems are working beyond their capacity (assuming they are sized correctly, which is another conversation for another day). In these scenarios, the systems may experience more wear, or operate outside the sweet spot of the capacity curve and run less efficiently.
If the conditions are extreme enough, and beyond the capacity of the system completely, the conditions inside the space will not match the thermostat setpoint, bringing us into the world of “unmet hours.” For example, if your air conditioning system is sized for a 95°F day and your locale is experiencing a 103°F day, you may not be able to maintain the 72°F cooling setpoint you want, but will be forced to deal with 80°F.
This all makes sense from the mechanical engineering perspective that many other energy modelers live in, but at Phius we are looking at having the passive building systems drive the project first, such as optimal window location, airtightness and insulation. There was some discussion about this in the case of a power outage, and trying to determine hours of impact on the building, but it seems there is still a great deal of research to do in this field. There are no agreed-upon conditions for simulating outages, or even the metric to rate the resilience of a building in an easily communicable way that captures the nuances and information to inform a decision. Opening keynote speaker Jason DeGraw of Oak Ridge National Laboratory (ORNL) said there is still a need to find “an EUI for thermal resilience.”
For decarbonization, Duncan Cox of Thornton Tomasetti detailed the research and standard writing for embodied carbon he had been involved with in the United Kingdom, and determined that just looking at envelope and structure, most of the control for embodied carbon lies in the structural engineer’s hands with material choices and structural efficiency concerns.
Unlike the thermal resilience issue, tons of CO2 equivalent emissions is a reliable “EUI” but the concerns around calculating and modeling these emissions lie within the databasing and scoping of the calculation. If looking at a project from the materials arriving on site and the emissions from onsite construction, some argue that you have a limited view and should be looking at transport to the site, and then the demolition, landfill and recycling of the building, called “cradle to cradle.” These also include accounting for operational emissions of the building, and discussion was had about accounting for hourly emission factors for the electrical grid, to better account for the decarbonization benefit of load shifting and load shedding through building controls. See Lisa’s blog posts about grid integration of passive building for more details.
While the above two topics make up the majority of the program requirements for REVIVE 2024 – the research project that has consumed every waking thought of mine – I presented on (and am rather passionate about) the education, training and engagement of newer energy modelers. Phius has been a good vehicle to get young people interested in modeling, and every young Phius Certified Consultant (CPHC®) I know has a reasonable understanding of the modeling, but a stronger foundation of the building science fundamentals, which is critical. I think these are core to being a good modeler, so you can do a back of the envelope calculation to confirm your modeling results, or have a better understanding that your checksums are within reason.
It is these mental checksums that take experience to gain, but I think they could be provided in some form of resources. BEMcyclopedia is a new resource for energy modelers that was presented on at the conference, and I think this type of resource library is the key to getting younger folks involved. While some people were floating the ideas of Tik-Toks related to energy modeling as the path forward, I made the point that many young people are still part of this “tutorial generation” where if there is a five to ten minute video, a PDF resource and someone who can answer your questions, then the bar to entry is much lower.
Another resource I think will help younger modelers as well as many of our CPHCs is Project Stasio. This is a competition that is part of the energy modeling conferences, and is a great online resource for inspiring different methods for presenting energy modeling results. Try out incorporating some of these graphics in your next presentation to a client and see if you can communicate complex energy conservation concepts to them more effectively.
As always, these conferences are a great way to network with various bright minds in the building sciences, and of course enjoy a meal together. We went to Terry Black’s, and if you are in Austin, Texas, be sure to head there for some brisket!
