Whole Building Life Cycle Assessment of a Living Building

Life cycle assessment (LCA) is a tool to quantify the environmental impacts of a product or system. This tool is used to assess environmental impacts of buildings over their lifespan. LCAs performed on standard buildings showed that the use phase dominated the impacts over the course of a building’s lifespan. Consequently, building energy efficiency was the target of reduction measures and high-performing buildings began to emerge. The design of living buildings followed, which are buildings that are defined as being net-positive energy and water. In these energy efficient buildings the significance of the use phase diminishes, shifting the focus to other life cycle stages. This research includes a whole-building LCA of a living building that focuses on the impacts from green building materials, a decentralized water system, a net-positive use phase, and the disposal of structural materials. The material processes used in this LCA were modified by removing the use of highly toxic chemicals per the product submittals; results showed carcinogenic impacts were decreased by up to 96%. The septic system, which is not aerated, used for wastewater treatment contributes to 37% of the global warming potential (GWP, kg CO2eq) for the whole building’s lifespan due to methane emissions. The solar panels on-site generate more electricity than the site demands, allowing for 44,000kWh of green energy to be returned to the grid. Lastly, a scenario analysis was performed on multiple waste streams for materials of two structural models (lumber or steel) with a concrete foundation. Results showed that based on the frame and waste stream selected, the end of life GWP impacts could vary from +14,000kg CO2eq to -10,500 kg CO2eq for the as-built structure. This whole-building LCA aims to identify and mitigate hotspots of the case study building, and to reduce life cycle impacts of living buildings moving forward

Impact of Lifetime on U.S. Residential Building LCA Results

Purpose: Many life cycle assessment (LCA) studies do not adequately address the actual lifetime of buildings and building products, but rather assume a typical value. The goal of this study was to determine the impact of lifetime on residential building LCA results. Including accurate lifetime data into LCA allows a better understanding of a product’s environmental impact that would ultimately enhance the accuracy of LCA results. Methods This study focuses on refining the U.S. residential building lifetime, as well as lifetime of interior renovation products that are commonly used as interior finishes in homes, to improve LCA results. Residential building lifetime data that presents existing trends in the U.S. was analyzed as part of the study. Existing data on product emissions were synthesized to form statistical distributions that were used instead of deterministic values. Product emissions data were used to calculate life cycle impacts of a residential model that was based on median U.S. residential home size. Results were compared to existing residential building LCA literature to determine the impact of using updated, statistical lifetime data. A Monte Carlo analysis was performed for uncertainty analysis. Sensitivity analysis results were used to identify hotspots within the LCA results. Results and discussion Statistical analysis of U.S. residential building lifetime data indicate that average building lifetime is 61 years and has a linearly increasing trend. Interior renovation energy consumption of the residential model that was developed by using average U.S. conditions was found to have a mean of 220 GJ over the life cycle of the model. Ratio of interior renovation energy consumption to pre-use energy consumption, which includes embodied energy of materials, construction activities, and associated transportation was calculated to have a mean of 34% for regular homes and 22% for low-energy homes. Ratio of interior renovation to life cycle energy consumption of residential buildings was calculated to have a mean of 3.9% for regular homes and 7.6% for low-energy homes. Conclusions Choosing an arbitrary lifetime for buildings and interior finishes, or excluding interior renovation impacts introduces a noteworthy amount of error into residential building LCA, especially as the relative importance of materials use increases due to growing number of low-energy buildings that have lower use phase impacts

A Hybrid Life Cycle Assessment Model for Construction Processess

This research qualitatively and quantitatively examined the environmental impacts due to the construction phase of commercial buildings. Previous building research often overlooked the construction phase and focused on the material and use phases, discounting the significant environmental impacts due to construction. The research was conducted using life cycle assessment (LCA) methodology, which is a systematic environmental management tool that analyzes and assesses holistically the environmental impacts of a product or process. This research contributed to further developing LCA research by focusing efforts on hybrid LCA modeling. The context of this research was established through examining green building rating systems, policy review, and project delivery methods with respect to the modeled results. Documented life cycle inventory results focused on PM emissions, GWP, SOx, NOx, CO, Pb, non-methane VOCs, energy usage, and solid and liquid wastes. Results compared with the entire building life cycle indicated that construction, while not as significant as the use phase, is as important as the other life cycle stages. In terms of hybrid LCA modeling, the augmented process based LCA proved to be effective in modeling the construction phase and allowed for efficiently combining process and input-output inventories. Including input-output results, especially construction service sectors, is critical in construction LCA modeling. One case study's results demonstrated that services had the highest level of methane emissions and were a significant contributor to CO2 emissions. Recommendations are made in terms of green building rating systems and national policies, including placing higher significance on construction activities within the United States Green Building Council's Leadership in Energy and Environmental Design (LEED) green building rating system

Application of Machine Learning for Predicting Building Energy Use at Different Temporal and Spatial Resolution under Climate Change in USA

Given the urgency of climate change, development of fast and reliable methods is essential to understand urban building energy use in the sector that accounts for 40% of total energy use in USA. Although machine learning (ML) methods may offer promise and are less difficult to develop, discrepancy in methods, results, and recommendations have emerged that requires attention. Existing research also shows inconsistencies related to integrating climate change models into energy modeling. To address these challenges, four models: random forest (RF), extreme gradient boosting (XGBoost), single regression tree, and multiple linear regression (MLR), were developed using the Commercial Building Energy Consumption Survey dataset to predict energy use intensity (EUI) under projected heating and cooling degree days by the Intergovernmental Panel on Climate Change (IPCC) across the USA during the 21st century. The RF model provided better performance and reduced the mean absolute error by 4%, 11%, and 12% compared to XGBoost, single regression tree, and MLR, respectively. Moreover, using the RF model for climate change analysis showed that office buildings’ EUI will increase between 8.9% to 63.1% compared to 2012 baseline for different geographic regions between 2030 and 2080. One region is projected to experience an EUI reduction of almost 1.5%. Finally, good data enhance the predicting ability of ML therefore, comprehensive regional building datasets are crucial to assess counteraction of building energy use in the face of climate change at finer spatial scale

Attacking the Global Plastics Waste Problem

"Plastic waste is a growing problem on a global scale, with the annual global production of synthetic polymers (now >500 million tons per year) predicted to triple by 2050.  At present, large volumes of polymeric waste migrate directly into the environment, and  less than 2% of polymeric waste is collected and reused in high-value applications.  A key obstacle to effective recycling is the vast number of formulations—each tailored to address a particular type of application—which is key to commercial success of polymers but creates a near-impossible separation problem during mechanical recycling and renders current approaches to chemical recycling inefficient. We are proposing to address this problem by creating a convergent academic center focused on the circular economy of synthetic polymers. This center will tightly integrate the science and engineering of plastics recycling (via a novel approach to chemical recycling of polyolefins using liquid metal catalysts and the a priori design of recyclable thermoset plastics) into the framework of life cycle and techno-economic analyses, and law and governance assessments.  Towards this goal, the center will convene faculty from the Swanson School of Engineering, the Dietrich School or Arts & Sciences, and the Law School, with the required complementary expertise. Efforts in year one will be focused on nucleating the collaborative efforts and producing initial results, which then will form the basis for convening a workshop at the start of year 2. This workshop will be used to scale up the effort by connecting to other US academics, industrial partners, and NSF and DOE program managers, in order to position ourselves for large center grants (e.g. NSF ERC, DOE EFRC), and create interest among potential industry sponsors (in particular members of the Alliance to End Global Plastic waste) to join and support this effort.

Investigation of the Relationship between Green Design and Project Delivery Methods

The selection of the project delivery method (PDM) for any project is critical--it establishes communication, coordination, and contractual issues between the owner, contractor, and designer. With an increase in the number of green design projects, understanding the relationship between the PDM and green design is paramount to project and contract management. It is reasonable to assume that a positive relationship between green design and design-build (DB) exists since both theoretically are intended to foster an integrated, holistic, and collaborative project. This research examines the relationship between the design-bid-build (DBB), construction management (CM), and DB PDMs and green design with the goal of establishing best practices and identifying potential synergies between them. The research collected information by conducting primarily telephone interviews with approximately twenty-five individuals, including owners, contractors, and designers involved in completed green design projects, mainly in the public sector. The interviews developed a general understanding of the current state of knowledge and experience and not a rigorous quantitative analysis. Upon completion of the interviews, the tabulated results were summarized and green project characteristics and project-PDM interactions emerged. Existing published research was evaluated to reveal aspects of PDMs independent of green design. Best practices were ascertained by combining information from the interviews and published research. Best practices are as follows: (1) Project implementation features--The decision to use DB as PDM on green design or other projects should be based on the specific project features; e.g., well-defined scope and adequate owner staffing. DB will not produce successful results on all projects. (2) Collaboration--Project team collaboration early in the design and construction process is an important aspect of green projects, and collaboration was considered somewhat more important in projects that used DB. (3) Experience--Team experience is important on all green design projects independent of the PDM. Owners should use a 'best value' selection process, which is more prevalent in DB projects, and include team experience as a criterion. The owner's role is critical with DB. (4) Leadership--Leadership is an important feature for all contracting parties involved in green design projects and it is a dominant success factor in DB projects. (5) Scope of work--A well-defined scope of work is important on all projects, independent of the PDM. In DB, improving the scope of work definition by developing a set of documents, typically comparable to the design development phase, as the basis for awarding a contract is called DB bridging. Using contracting techniques such as DB bridging can result in better identification of expected quality and improves the owner's level of control. (6) Funding and Budget--Having adequate funding and budget for the given scope of work is particularly important in a green design project. Public funding restrictions may not allow use of certain PDMs, and the nature of public funding streams may make non-traditional PDMs more difficult. (7) Complexity and Flexibility--Complexity and flexibility is a project feature that is more specific to green design projects and is more frequently associated with DB. (8) Control and Accountability--Control and accountability is a problem associated with DB more than with DBB. It is not specific to green design projects. DB Bridging can be used to offset the lack of control with traditional DB. The use of green design and DB is increasing and understanding the linkage between the two is important. This research has found that while linkages do exist, the owner needs to carefully consider all aspects of a green design project before making the decision of the most appropriate PDM

Investigation of Energy Modelling Methods of Multiple Fidelities: A Case Study

Building energy modelling has become an integral part of building design due to energy consumption concerns in sustainable buildings. As such, energy modelling methods have evolved to the point of including higher-order physics, complex interconnected components and sub-systems. Despite advances in computer capacity, the cost of generating and running complex energy simulations makes it impractical to rely exclusively on such higher fidelity energy modelling for exploring a large set of design alternatives. This challenge of exploring a large set of alternatives efficiently might be overcome by using surrogate models to generalize across the large design space from an evaluation of a sparse subset of design alternatives by higher fidelity energy modelling or by using a set of multi-fidelity models in combination to efficiently evaluate the design space. Given there exists a variety of building energy modelling methods for energy estimation, multi-fidelity modelling could be a promising approach for broad exploration of design spaces to identify sustainable building designs. Hence, this study investigates energy estimates from three energy modelling methods (modified bin, degree day, EnergyPlus) over a range of design variables and climatic regions. The goal is to better understand how their outputs compare to each other and whether they might be suitable for a multi-fidelity modelling approach. The results show that modified bin and degree day methods yield energy use estimates of similar magnitude to each other but are typically higher than results from EnergyPlus. The differences in the results were traced, as expected, to the heating and cooling end-uses, and specifically to the heat gain and heat loss through opaque (i.e., walls, floors, roofs) and window surfaces. The observed trends show the potential for these methods to be used for multi-fidelity modelling, thereby allowing building designers to broadly consider and compare more design alternatives earlier in the design process

Do single-use medical devices containing biopolymers reduce the environmental impacts of surgical procedures compared with their plastic equivalents?

Background: While petroleum-based plastics are extensively used in health care, recent developments in biopolymer manufacturing have created new opportunities for increased integration of biopolymers into medical products, devices and services. This study compared the environmental impacts of single-use disposable devices with increased biopolymer content versus typically manufactured devices in hysterectomy. Methods: A comparative life cycle assessment of single-use disposable medical products containing plastic(s) versus the same single-use medical devices with biopolymers substituted for plastic(s) at Magee-Women’s Hospital (Magee) in Pittsburgh, PA and the products used in four types of hysterectomies that contained plastics potentially suitable for biopolymer substitution. Magee is a 360-bed teaching hospital, which performs approximately 1400 hysterectomies annually. Results: There are life cycle environmental impact tradeoffs when substituting biopolymers for petroplastics in procedures such as hysterectomies. The substitution of biopolymers for petroleum-based plastics increased smog-related impacts by approximately 900% for laparoscopic and robotic hysterectomies, and increased ozone depletion-related impacts by approximately 125% for laparoscopic and robotic hysterectomies. Conversely, biopolymers reduced life cycle human health impacts, acidification and cumulative energy demand for the four hysterectomy procedures. The integration of biopolymers into medical products is correlated with reductions in carcinogenic impacts, non-carcinogenic impacts and respiratory effects. However, the significant agricultural inputs associated with manufacturing biopolymers exacerbate environmental impacts of products and devices made using biopolymers. Conclusions: The integration of biopolymers into medical products is correlated with reductions in carcinogenic impacts, non-carcinogenic impacts and respiratory effects; however, the significant agricultural inputs associated with manufacturing biopolymers exacerbate environmental impacts

Embed systemic equity throughout industrial ecology applications: How to address machine learning unfairness and bias

\ua9 2024 The Authors. Journal of Industrial Ecology published by Wiley Periodicals LLC on behalf of International Society for Industrial Ecology. Recent calls have been made for equity tools and frameworks to be integrated throughout the research and design life cycle —from conception to implementation—with an emphasis on reducing inequity in artificial intelligence (AI) and machine learning (ML) applications. Simply stating that equity should be integrated throughout, however, leaves much to be desired as industrial ecology (IE) researchers, practitioners, and decision-makers attempt to employ equitable practices. In this forum piece, we use a critical review approach to explain how socioecological inequities emerge in ML applications across their life cycle stages by leveraging the food system. We exemplify the use of a comprehensive questionnaire to delineate unfair ML bias across data bias, algorithmic bias, and selection and deployment bias categories. Finally, we provide consolidated guidance and tailored strategies to help address AI/ML unfair bias and inequity in IE applications. Specifically, the guidance and tools help to address sensitivity, reliability, and uncertainty challenges. There is also discussion on how bias and inequity in AI/ML affect other IE research and design domains, besides the food system—such as living labs and circularity. We conclude with an explanation of the future directions IE should take to address unfair bias and inequity in AI/ML. Last, we call for systemic equity to be embedded throughout IE applications to fundamentally understand domain-specific socioecological inequities, identify potential unfairness in ML, and select mitigation strategies in a manner that translates across different research domains

Do single-use medical devices containing biopolymers reduce the environmental impacts of surgical procedures compared with their plastic equivalents?

Background: While petroleum-based plastics are extensively used in health care, recent developments in biopolymer manufacturing have created new opportunities for increased integration of biopolymers into medical products, devices and services. This study compared the environmental impacts of single-use disposable devices with increased biopolymer content versus typically manufactured devices in hysterectomy. Methods: A comparative life cycle assessment of single-use disposable medical products containing plastic(s) versus the same single-use medical devices with biopolymers substituted for plastic(s) at Magee-Women’s Hospital (Magee) in Pittsburgh, PA and the products used in four types of hysterectomies that contained plastics potentially suitable for biopolymer substitution. Magee is a 360-bed teaching hospital, which performs approximately 1400 hysterectomies annually. Results: There are life cycle environmental impact tradeoffs when substituting biopolymers for petroplastics in procedures such as hysterectomies. The substitution of biopolymers for petroleum-based plastics increased smog-related impacts by approximately 900% for laparoscopic and robotic hysterectomies, and increased ozone depletion-related impacts by approximately 125% for laparoscopic and robotic hysterectomies. Conversely, biopolymers reduced life cycle human health impacts, acidification and cumulative energy demand for the four hysterectomy procedures. The integration of biopolymers into medical products is correlated with reductions in carcinogenic impacts, non-carcinogenic impacts and respiratory effects. However, the significant agricultural inputs associated with manufacturing biopolymers exacerbate environmental impacts of products and devices made using biopolymers. Conclusions: The integration of biopolymers into medical products is correlated with reductions in carcinogenic impacts, non-carcinogenic impacts and respiratory effects; however, the significant agricultural inputs associated with manufacturing biopolymers exacerbate environmental impacts