By running ventilation at four air changes per hour—a challenging proposition—labs can achieve 60% reduction from the current baseline. Photovoltaics and carbon offsets can make up the difference.
Image: HOK Laboratories are notorious energy hogs. They also tend to have high embodied carbon when built new. Reining in the carbon footprint of this booming building type will be necessary in order to reach the net-zero-carbon goals of both the American Institute of Architects’ and the Royal Institute of British Architects’ respective 2030 Challenges. But how?
Two analysts at HOK have modeled multiple building scenarios to find the answer. In Pathway to Net-Zero-Carbon Labs, Gary Clark and Rob McGill offer guidance on how project teams can cut both operational and embodied carbon of labs to meet 2030 targets.
Using Grasshopper, Energy+, Ladybug, Honeybee, and Octopus, the two developed solutions for net-zero operational carbon that include:
Limiting ventilation to four air changes per hour (4 ACH)
Electrifying the entire building
Installing triple-glazed windows
Significantly boosting insulation, airtightness, and shading
Using ground-source heat pumps
These means brought modeled grid-energy consumption down by 60% compared to a well-performing baseline lab. By adding onsite photovoltaics, the total can be reduced a further 15%. “An additional 25% reduction in energy would have to come from certified offsetting programs—a necessary requirement until the energy grid itself is decarbonized,” the authors say.
Structural elements introduced the most embodied carbon, and the net-zero-carbon option achieved the best performance, using a mass timber structure (not accounting for carbon sequestration).
Timber cladding and windows were also important to bringing down embodied carbon.
The net-zero option used an insulated pre-cast panel façade with aluminum curtainwall.
Little is known about the embodied carbon of mechanical, electrical, and plumbing (MEP) systems, so MEP elements were left the same among all the models studied.
All the same, the report notes that the best way to save embodied carbon is to reuse existing lab buildings rather than constructing new ones.
“HOK’s initial analysis indicates that, while not easy, it is possible to build and operate labs in accordance with the sustainable design goals of the RIBA and AIA 2030 challenges,” the authors conclude.
Since 4 ACH is not a viable option for many labs, a next step for HOK researchers is to explore the possibility of higher air-change rates while still maintaining net-zero operational carbon.
Melton, P. (2022, March 18). Are Net-Zero-Carbon Labs Feasible?. Retrieved from https://www.buildinggreen.com/newsbrief/are-net-zero-carbon-labs-feasible
It's been too long for me to recall the specifics of JCVI's net zero, carbon neutral lab with Peter Rumsey and ZGF, which won an AIA COTE in 2016. I don't think embodied carbon in materials, embedded carbon in water & wastewater were tallied. Ditto for Scope 1 refrigerants.
It's on NBI's net zero db as "emerging" which is puzzling. So I can't say how well it's perfroming. One thing I'm rather certain of is that we were using the grid for storage and not buying any offsets--the project does have thermal storage. Even if SONG hadn't been decommisioned, the grid isn't 100% carbon free, 100% of the time. The notion of 100% carbon-free operations, 100% of the time was the premise for Shanti Pless and Paul Torcellini's 2020 ACEEE paper "ZEB v2.0". It's lofty and unless you provide a massive amount of battery storage, it will be a truly daunting target. I think the more practical target is reduced lifetime carbon from all Scope 1, 2 & 3 sources--that includes the transportation emissions. You're not likely to get to zero, but you can try and you shouldn't take a silo'ed approach to the optimaztion--that was the point of my ACEEE paper with David Goldstein and my 2020 Greenbuild talk with Kelly Roberts, Peter Haas and Ankur Podder.
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