Web Exclusive Q&A – 749 University Row
Q&A with Scott Hackel, Member ASHRAE, is principal energy engineer at Seventhwave, a nonprofit research and engineering firm in Madison, Wis., and Chicago.
HPB: This case study focuses on the sustainability of this project from an environmental and economic standpoint. Why have developers (as opposed to owners who occupy their buildings) been slower to pursue highly efficient buildings, and is 749 University Row representative of a broader growing interest in sustainable design among developers?
Hackel: I think developers have been slower to pursue highly efficient buildings because they perceive a risk that their tenants will not fully value the additional performance, and the developer will therefore not realize a return on their investment because they cannot capture that value in rent. I think there is some growth to more sustainable design among developers, but it is still on a slow incline.
HPB: As a speculative project with unknown future tenants, the building team pursued a high performance design while also seeking to create an environment that would be welcoming to tenants. For instance, in the HVAC selection process a unitary ground-source showed slightly better performance than a ground-source variable refrigerant flow system. But the unitary system would have required heat pumps to be distributed throughout the building, which was highly undesirable for the owner, so the team selected the VRF system. How did the building team navigate these the dual goals of performance and creating a welcoming environment for tenants, and what can be learned from the project’s results?
Hackel: The team navigated these types of trade-offs through conversation, directly, between the developer, designer, contractor and relevant consultants. There were simply more of these conversations on the 749 University Row project than we’d typically have in the early (schematic) phase. Having four to five additional conversations about building performance turned out to be well worth the investment of a few hours’ time at that early stage.
HPB: One of the reasons that Seventhwave moved its offices to 749 University Row was to “walk the talk.” How has this new location helped Seventhwave better communicate the benefits of sustainable design from the perspectives of energy efficiency and cost?
Hackel: This new location has been great for Seventhwave. On the research side, we’ve actually be able to conduct extensive measurement of several of the systems, and we’ve included three of those systems in broader research where we also monitored other buildings. These research efforts have already led to a few successful publications and interesting conclusions. For our consulting practice, we frequently reference what we did on our building when we’re making recommendations to clients, especially regarding office design, lighting, and variable refrigerant flow (VRF). And our education team has seen a lot more people actually visit our office to receive live education in our large training room. Those educational events have generally included either a short discussion about the components of the building, or often even a full tour, prior to or after the event.
HPB: In addition to monitoring the performance of this building’s demand controlled ventilation (DCV) system, Seventhwave has conducted a field study of six DCV systems in Minnesota. What are some of the key findings that building teams could use when considering and designing DCV systems?
Hackel: We learned a lot about what is being done right and what is being done wrong with DCV, and much of it related directly to designers. In short, designers need to ensure that they complete a full design of the system with the construction documents. This may seem obvious, but a lot of projects simply label which rooms get CO2 sensors—and leave the rest up to the controls contractor. This leads to systems that don’t perform. The designer needs to select a specific sequence—and there is detailed advice around this in our report at Seventhwave.org/dcv—and then document the elements of that sequence, including CO2 setpoint, lower airflow limit and upper airflow limit. Designers should also draw the specific sensor location in the room, and include airflow measurement requirements AND location.
HPB: Task tuning, the practice of using dimmable lighting to adjust light levels so that illuminance is appropriate for the activity in the space, resulted in significant lighting energy savings in 749 University Row. What are some of the key findings from the study of this project?
Hackel: A fact sheet with the key findings from our task tuning research, "Summary of Findings From a Field Study of Task Tuning," can be found at http://tinyurl.com/juv8t7p. See p. 2 for lessons learned for utility programs, and p. 3 for lessons learned on how to task tune.
HPB: The building’s inviting entry stairwell is designed to encourage people to take the stairs rather than the elevator. In what other ways are energy-saving behaviors encouraged?
Hackel: I think the bike facilities are the other largest behavior-impacting feature of the overall building. Most cars must park in the shared ramp across the street, but all bikers are allowed to park in the heated basement directly under their office. Lockers and showers are convenient to the entryway. It’s just very inviting to bikers. All other behavior elements would be in the tenant spaces, and individual to each.
HPB: What feedback has been received from people who use 749 University Row, and how has that feedback been used to fine-tune building operations?
Hackel: Central feedback has been primarily related to the HVAC system, as you’d expect. The same contractor who installed the system holds a maintenance and operations contract, and they’ve been directly responsive to feedback from the tenants. The primary change thus far has been thermostat re-tuning/programming, along with some minor adjustment of the dedicated outdoor air system (DOAS).
HPB: You co-created an energy modelers group in Madison, Wis., through ASHRAE to assist others in gaining expertise. How have you seen building energy modeling evolve during your career, and what are some of the major learning curves for those new to the field?
Hackel: This is an entire article unto itself. The main thing that we’ve noticed is that energy modeling has evolved from a niche service to one that most major engineering and architectural/engineering firms must feel comfortable conducting. And on a much higher percentage of their projects. The metrics from the 2030 Challenge suggest that there are still a lot of projects that could use more energy modeling, but it’s refreshing to see a majority of projects conduct even a little modeling, and often as part of the engineers’ base scope.
The biggest learning curve now is probably in implementing the advanced systems that are available—software is no longer a barrier for basic systems, but now there are so many more complex HVAC systems, lighting controls and other systems that cannot be directly modeled in the software. These systems require solid energy modeling judgment to conduct workarounds or custom models, which is not something that can be learned in a two-day software course.
HPB: Your personal passions include endurance sports, home brewing and exploring the outdoors. How do these interests connect with or inform your professional pursuits as an energy engineer?
Hackel: My interest in outdoors (and outdoor sports) is inextricably linked to how I work in my day job to reduce environmental impact. The example that hits me most directly is use of the lakes here in Wisconsin—kayaking, doing triathlons or just swimming with my kids—I’m keenly aware of the water quality. And it’s surprising how often this comes up when working with the built-environment—whether considering rainwater collection or saving energy from local power plants, which generally use those surface water bodies too.