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On the Tradeoffs between Embodied and Operational Carbon in Building Envelope Design: The Impact of Local Climates and Energy Grids

‌Méndez Echenagucia, T., Moroseos, T., & Meek, C. (2023).  On the Tradeoffs between Embodied and Operational Carbon in Building Envelope Design: The Impact of Local Climates and Energy Grids. Energy and Buildings, 238.

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Abstract

Embodied and operational carbon tradeoffs in building envelopes are studied. • Envelope variables include wall assemblies, WWRs, glazing and shading. • Energy decarbonization models are used to determine the 30-year operational carbon. • Results show the importance of a total carbon approach to envelope design. • Over or under insulation can result in waste of 10–150 kgCO 2 e/m2. The building envelope has a substantial influence on a building's life cycle operational and embodied carbon emissions. Window-to-wall ratios, wall assemblies, shading and glazing types, have been shown to have a significant impact on total emissions. This paper provides building designers, owners, and policy makers with actionable guidance and a prioritization framework for establishing co-optimized lifecycle carbon performance of facade assembly components in a broad spectrum of climate contexts and energy carbon intensities. A large parametric study of building envelopes is conducted using building performance simulation and cradle-to-gate embodied carbon calculations in 6 US cities. The authors derive the total carbon emissions optimization for commercial office and residential space types using standard code-reference models and open-source lifecycle data. Comparisons between optimal total carbon solutions and (i) optimal operational carbon and (ii) minimum required assemblies, show the impact of under and over investing in envelope-related efficiency measures for each climate. Results show how the relationship between embodied and operational carbon is highly localized, that optimal design variables can vary significantly. In low carbon intensity energy grids, over investment in envelope embodied carbon can exceed as 10 kgCO 2 e/m2, while under investment in high carbon intensity grids can be higher than 150 kgCO 2 e/m2.

Keywords

Building performance simulation; Embodied carbon; Operational carbon; Parametric modeling

Allison Hyatt

Allison Hyatt is a Researcher with the Carbon Leadership Forum at the University of Washington. Prior to joining the CLF, Allison oversaw the design development of various high performance buildings for public sector projects at Siegel & Strain Architects. With years of experience as an architect, she prioritizes forging links between architectural practice and research. As a graduate student, her research assessed metrics to compare among operational carbon savings, embodied carbon expenditures, and monetary costs of different decarbonization strategies over time. In the spring of 2022, she received her Masters degree in Design Studies with a concentration in Energy and Environment from the Harvard University Graduate School of Design.

Anthony Hickling

Anthony Hickling joins CLF with experience in environmental and social sustainability as well as nonprofit management and fundraising. His foundations in sustainable building are informed by experience at Presidio Graduate School where he received an MBA in Sustainable Solutions, as well as his work on the sustainability team at Webcor Builders in San Francisco. Through academic and professional experience he has learned to navigate the priorities of traditional business stakeholders while incorporating social and environmental externalities. From executing successful marketing plans to determining research priorities, Anthony believes that wide impact considerations and diversity of thought should be embedded into all decision-making.

Brad Benke

Brad Benke, AIA, is a Research Engineer at the Carbon Leadership Forum focused on developing data-driven resources to help practitioners and policymakers adopt and scale decarbonization strategies in the built environment. With a background in deep-green architecture and consulting, Brad works to synthesize and improve life cycle assessment practices and tools within the AEC industry and deliver practical solutions for low-carbon building design and construction. His recent work includes leading the CLF WBLCA Benchmark Study and developing the background data and methodologies for the CLF Embodied Carbon Policy Reduction Calculator. Brad is a former co-chair of AIA Seattle’s Committee on the Environment, and a former Senior Architect at McLennan Design, where he led diverse teams and stakeholders toward achieving decarbonization goals for buildings and organizations across the country.

Megan Kalsman

Megan Kalsman is a Policy Researcher with the Carbon Leadership Forum at the University of Washington. She specializes in advancing the procurement of low-carbon materials and informs the development and implementation of cross-sectoral climate policies targeting embodied carbon.

Before joining the CLF, Megan completed her Master of Science degree at Lund University in Sweden in Environmental Management and Policy with the International Institute for Industrial Environmental Economics. She published her thesis project in 2021, on the intersection of gender equality with different environmental issues like climate change, biodiversity, and chemicals on an international policy scale.

Prior to studying in Sweden, Megan coordinated environmental policies and programs for local government agencies in California with a focus on toxic chemical reduction and pollution prevention. She helped in developing the first in the nation ban on toxic flame retardant chemicals in San Francisco. This served as a model policy for the State of California and other states in the U.S. passing similar policies. Her undergraduate degree was in Environmental Studies at San Francisco State University with a minor in Urban Planning and the Built Environment.

Megan’s work at the CLF combines her environmental research experience and policy design background. She strives to frame her work with an intersectional lens each day – protecting the health of people and the environment in an equitable way. At the CLF, Megan enjoys interacting with a variety of stakeholders around embodied carbon policies and ultimately working together towards a more sustainable and just future.

Evaluation Strategies on the Thermal Environmental Effectiveness of Street Canyon Clusters: A Case Study of Harbin, China

Li, Guanghao; Cheng, Qingqing; Zhan, Changhong; Yocom, Ken P. (2022). Evaluation Strategies on the Thermal Environmental Effectiveness of Street Canyon Clusters: A Case Study of Harbin, China. Sustainability, 14(20).

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Abstract

Urban overheating significantly affects people's physical and mental health. The addition of street trees is an essential, economical, and effective means by which to mitigate urban heat and optimize the overall thermal environment. Focusing on typical street canyon clusters in Harbin, China, landscape morphology was quantified by streetscape interface measurements (sky view factor, tree view factor, and building view factor). Through ENVI-met simulations, the correlation mechanism between streetscape interface measurements and thermal environment was evaluated, and optimization methods for assessing the thermal environment of urban streets were proposed. The results revealed: (1) The thermal environment optimization efficiency of general street canyon types was greatest when street tree spacing was 12 m. At present, the smaller spacing has not been simulated and may yield better thermal environment results. The average decrease in temperature (Ta), relative humidity (RH) and mean radiant temperature (MRT) was 0.78%, 2.23%, and 30.20%, respectively. (2) Specific street canyon types should adopt precise control strategies of streetscape interface according to their types to achieve the optimal balance between thermal environment optimization and cost. (3) Streetscape interface measurements and thermal environment indexes show quadratic correlation characteristics, and are critical points for further investigation. The conclusions are more specific than previous research findings, which are of great significance for decreasing the urban heat island effect at the block scale, improving residents' physical and mental health, and improving the urban environment quality.

Keywords

Heat Mitigation Strategies; Urban Green Areas; Sky View Factor; Cold Region; Comfort; Tree; Landscape; Park; Simulation; Density; Street Canyon Clusters; Streetscape Interface Measurement; Envi-met Simulation; Thermal Optimization

On the Tradeoffs between Embodied and Operational Carbon in Building Envelope Design: The Impact of Local Climates and Energy Grids

Echenagucia, Tomas Mendez; Moroseos, Teresa; Meek, Christopher. (2023). On the Tradeoffs between Embodied and Operational Carbon in Building Envelope Design: The Impact of Local Climates and Energy Grids. Energy & Buildings, 278.

View Publication

Abstract

The building envelope has a substantial influence on a building's life cycle operational and embodied car-bon emissions. Window-to-wall ratios, wall assemblies, shading and glazing types, have been shown to have a significant impact on total emissions. This paper provides building designers, owners, and policy makers with actionable guidance and a prioritization framework for establishing co-optimized lifecycle carbon performance of facade assembly components in a broad spectrum of climate contexts and energy carbon intensities. A large parametric study of building envelopes is conducted using building perfor-mance simulation and cradle-to-gate embodied carbon calculations in 6 US cities. The authors derive the total carbon emissions optimization for commercial office and residential space types using standard code-reference models and open-source lifecycle data. Comparisons between optimal total carbon solu-tions and (i) optimal operational carbon and (ii) minimum required assemblies, show the impact of under and over investing in envelope-related efficiency measures for each climate. Results show how the rela-tionship between embodied and operational carbon is highly localized, that optimal design variables can vary significantly. In low carbon intensity energy grids, over investment in envelope embodied carbon can exceed as 10 kgCO2e/m2, while under investment in high carbon intensity grids can be higher than 150 kgCO2e/m2.Published by Elsevier B.V.

Keywords

Facades; Building-integrated Photovoltaic Systems; Carbon Emissions; Carbon; Building Performance; Building Designers; Building Envelopes; Refuse Containers; Building Performance Simulation; Embodied Carbon; Operational Carbon; Parametric Modeling; Environmental-impact; Search

Qing Shen awarded funding for commute research survey

The Mobility Innovation Center announced that Qing Shen, professor of Urban Design & Planning and an expert in transportation planning and policy, has received a $100,000 award to study commuting patterns and develop a model to understand the effect of telework and flexible scheduling. The project will build off the existing Commute Trip Reduction (CTR) survey for employers who are in the CTR program as required by state law in the central city portion of Seattle. In addition, a complementary…

Celina Balderas Guzmán

Celina Balderas Guzmán, PhD, is Assistant Professor in the Department of Landscape Architecture. Dr. Balderas’ research spans environmental planning, design, and science and focuses on climate adaptation to sea level rise on the coast and urban stormwater inland. On the coast, her work demonstrates specific ways that the climate adaptation actions of humans and adaptation of ecosystems are interdependent. Her work explores how these interdependencies can be maladaptive by shifting vulnerabilities to other humans or non-humans, or synergistic. Using ecological modeling, she has explored these interdependencies focusing on coastal wetlands as nature-based solutions. Her work informs cross-sectoral adaptation planning at a regional scale.

Inland, Dr. Balderas studies urban stormwater through a social-ecological lens. Using data science and case studies, her work investigates the relationship between stormwater pollution and the social, urban form, and land cover characteristics of watersheds. In past research, she developed new typologies of stormwater wetlands based on lab testing in collaboration with environmental engineers. The designs closely integrated hydraulic performance, ecological potential, and recreational opportunities into one form.

Her research has been funded by major institutions such as the National Science Foundation, National Socio-Environmental Synthesis Center, UC Berkeley, and the MIT Abdul Latif Jameel Water and Food Systems Lab. She has a PhD in the Department of Landscape Architecture and Environmental Planning from the University of California, Berkeley. Previously, she obtained masters degrees in urban planning and urban design, as well as an undergraduate degree in architecture all from MIT.

Narjes Abbasabadi

Narjes Abbasabadi, Ph.D., is an Assistant Professor in the Department of Architecture at the University of Washington. Dr. Abbasabadi also leads the Sustainable Intelligence Lab. Abbasabadi’s research centers on sustainability and computation in the built environment. Much of her work focuses on advancing design research efforts through developing data-driven methods, workflows, and tools that leverage the advances in digital technologies to enable augmented intelligence in performance-based and human-centered design. With an emphasis on multi-scale exploration, her research investigates urban building energy flows, human systems, and environmental and health impacts across scales—from the scale of building to the scale of neighborhood and city.

Abbasabadi’s research has been published in premier journals, including Applied Energy, Building and Environment, Energy and Buildings, Environmental Research, and Sustainable Cities and Society. She received honors and awards, including “ARCC Dissertation Award Honorable Mention” (Architectural Research Centers Consortium (ARCC), 2020), “Best Ph.D. Program Dissertation Award” (IIT CoA, 2019), and 2nd place in the U.S. Department of Energy (DOE)’s Race to Zero Design Competition (DOE, 2018). In 2018, she organized the 3rd IIT International Symposium on Buildings, Cities, and Performance. She served as editor of the third issue of Prometheus Journal, which received the 2020 Haskell Award from AIA New York, Center for Architecture.

Prior to joining the University of Washington, she taught at the University of Texas at Arlington and the Illinois Institute of Technology. She also has practiced with several firms and institutions and led design research projects such as developing design codes and prototypes for low-carbon buildings. Most recently, she practiced as an architect with Adrian Smith + Gordon Gill Architecture (AS+GG), where she has been involved in major projects, including the 2020 World Expo. Abbasabadi holds a Ph.D. in Architecture from the Illinois Institute of Technology and Master’s and Bachelor’s degrees in Architecture from Tehran Azad University.