Joyce Smith Cooper

Review and analysis of PEM fuel cell design and manufacturing

Abstract Design and manufacturing alternatives for Proton Exchange Membrane (PEM) fuel cells are described and analysed within the context of vehicle applications. Specifically, following a review of many alternatives, 16 polymer electrolyte membranes, 2 types of gas diffusion layers (GDL), 8 types of anode catalysts, 4 types of cathode catalysts and over 100 bipolar plate designs are recommended for further study. This work not only reviews membrane electrode assembly manufacturing options and synthesis processes for many of the membranes and for the gas diffusion layers, but also adds to the bipolar plate fabrication options described in literature. This work is intended to facilitate material and process selection through the consideration of the variety of design and manufacturing alternatives prior to capital investment for wide-scale production.

Specifying functional units and reference flows for comparable alternatives

Goal, Scope, and BackgroundDespite documentation of product lifetime, performance, and system dependency issues, requirements for specifying functional units and reference flows in LCA have not been developed. The ISO standards simply note that selection between functions is dependent on the goals and scope of the study, that the functional unit must be clearly defined and measurable, and that the reference flows are the amount of product necessary per functional unit. The goal of this work is to suggest and demonstrate the use a set of requirements for specifying the functional unit and reference flows for comparative LCAs.MethodsThe suggested requirements were developed to address the lifetime, performance, and system dependency issues described in LCA literature and to ensure adequate information is available for the interpretation of results. Also, well developed methods for conceptual design were used to formulate aspects of the requirements to improve comparability of alternatives. A case study demonstrates the use of the requirements in materials selection for aircraft design. In the case study, functional units are specified for the component being designed and for the aircraft. Similarly, reference flows for the component, component interfaces, and the aircraft are quantified based on parametric and linear estimation models. Finally, an interpretation of data quality, uncertainty, assumptions, and limitations are presented.Results and DiscussionThe requirements are shown to be particularly important when the product be assessed operates as part of a larger system and when there are performance differences among alternatives. The case study illustrates the importance of including consideration of system and interface materials and energy flows in the comparison of aircraft components. Specifically, because the mass of interface materials is estimated as more than the difference in subsystem masses, differences in the variable mass of the aircraft and the lifetime fuel consumption are accounted for in the reference flows.ConclusionsSome practitioners have recognized difficulties in accounting for product lifetime, performance, and system dependencies in LCA, even though a set of requirements has not been included in literature or in the ISO standards. The suggested requirements presented in this work were found to be useful in accounting for differences in materials and energy flows and in providing a transparent presentation, assessment, and interpretation of reference flows and ultimately in the LCA results.Recommendations and OutlookThis work is significant because the specification of the functional unit and the definition of the reference flows dictate the materials and processes included in the LCA. Future work is needed to test the general applicability of the suggested requirements to a wide variety of product systems.

New Directions in Design for Manufacturing

This paper gives an overview of research that is expanding the domain of design for manufacturing (DFM) into new and important areas. This paper covers DFM and concurrent engineering, DFM for conceptual design, DFM for embodiment design, DFM for detailed design, design for production, platform design for reducing time-to-market, design for system quality, design for life cycle costs, and design for environment. The paper concludes with some general guidelines that suggest how manufacturing firms can develop useful, effective DFM tools.

Converting lignocellulosic solid waste into ethanol for the State of Washington: an investigation of treatment technologies and environmental impacts.

There is little research literature on the conversion of lignocellulosic rich waste streams to ethanol, and even fewer have investigated both the technical aspects and environmental impacts together. This study assessed technical and environmental challenges of converting three lignocellulosic waste streams to ethanol: municipal solid waste (MSW), low grade mixed waste paper (MWP), and organic yard waste (YW). Experimental results showed high conversion yields for all three streams using suitable conversion methods. Environmental impacts are highly dependent on conversion technology, and process conditions used. Life cycle assessment results showed that both chemicals production and waste collection are important factors to be included within a waste-to-ethanol study.

Life Cycle Energy Analysis as a Method for Material Selection

This paper presents a method of performing Life Cycle Energy Analysis (LCEA) for the purpose of material selection. The method applies product analysis methods to the evaluation of material options for automotive components. Specifically, LCEA is used to compare material options for a bumper-reinforcing beam on a 1030 kg vehicle. In this analysis, glass fiber composites and high-strength steel beams result in the lowest life cycle energy consumption. This paper also presents a set of life cycle energy terms designed to clearly distinguish between energy consumption occurring during different phases of a products life cycle. In addition, this paper compares the results of the LCEA method to those of other energy analyses and demonstrates how different methods of varying thoroughness can result in different material selections. Finally, opportunities are identified for extending this type of analysis beyond both automotive components and energy consumption. In particular, this paper identifies the need to develop similar methods for other environmental indicators.

Parameterization in Life Cycle Assessment inventory data: review of current use and the representation of uncertainty

PurposeParameterization refers to the practice of presenting Life Cycle Assessment (LCA) data using raw data and formulas instead of computed numbers in unit process datasets within databases. This paper reviews parameterization methods in the European Reference Life Cycle Data System (ELCD), ecoinvent v3, and the US Department of Agricultures Digital Commons with the intent of providing a basis for continued methodological and coding advances.MethodsParameterized data are reviewed and categorized with respect to the type (raw data and formulas) and what is being represented (e.g., consumption and emission rates and factors, physical or thermodynamic properties, process efficiencies, etc.). Parameterization of engineering relationships and uncertainty distributions using Smirnov transforms (a.k.a. inverse transform sampling), and ensuring uncertain individual fractions (e.g., market shares) sum to the total value of interest are presented.ResultsSeventeen categories of parameters (raw data and formulas) are identified. Thirteen ELCD unit process datasets use 975 parameters in 12 categories, with 124 as raw data points and 851 as formulas, and emission factors as the most common category of parameter. Five additional parameter categories are identified in the Digital Commons for the presentation and analysis of data with uncertainty information, through 146 parameters, of which 53 represent raw data and 93 are formulas with most being uncertainty parameters, percentages, and consumption parameters.ConclusionsParameterization is a powerful way to ensure transparency, usability, and transferability of LCI data. Its use is expected to increase in frequency, the categories of parameters used, and the types of computational methods employed.

Commentary on issues in data quality analysis in life cycle assessment

PurposeFor compliance with the ISO standard 14044, comparative life cycle assessments are required to address data quality for time-related coverage, geographic coverage, technology coverage, precision, completeness, representativeness, consistency, reproducibility, sources of the data and uncertainty of the information. As the community of practitioners and data developers grows, the purpose of this commentary is to initiate discussion of current issues and opportunities for improvement in data quality analysis.MethodsCommonly applied data quality analysis methods are described as ranging from the collection of only qualitative information to the assignment of numeric scores. Common interpretations of data quality information are described as ranging from comparison in raw form to contribution and sensitivity analysis results, combination into an aggregate/multiaspect score, or use to infer data uncertainty. Method strengths and issues are described.ResultsThe strengths of current data quality analysis methods lie in the consideration of the data quality aspects specified by the ISO standards and in the differentiation of low and high data quality. Weaknesses, however, lie in unrepeatable scoring criteria, aggregation of data quality information in a way that is difficult to interpret or misinterpreted and the use of data quality information in the estimation of uncertainty with no basis for accuracy.ConclusionIt is found that among commonly applied methods there exists a need for improved repeatability and interpretability. When combined with emerging efforts to provide reliable uncertainty data to support the use of data quality information with contribution and sensitivity analysis results and efforts that have improved consideration of completeness, the future of data quality analysis promises substantial contribution to the field.

Teaching Life-Cycle Assessment at Universities in North America, Part II

Journal of Industrial Ecology 13 Faculty members at universities throughout North America are working to prepare students to meet the growing need for those trained in industrial ecology and related fields. Lifecycle assessment (LCA) is an important component of this training. To gain a better understanding of their activities related to LCA, we sent informal questionnaires in December 1998 to those receiving the Journal of Industrial Ecology and others teaching at the university level in the United States and Canada. We report on and assess the results of the questionnaire in this and the forthcoming column. The questionnaire focused on the characteristics of courses in which LCA is taught and related teaching resources. The first section contained background questions for all respondents to answer. The second section contained more detailed questions to be answered as time permitted. Although the questionnaire was intended to be broad in scope, because of the method of participant selection it cannot be considered statistically representative of activities in North America. Of the 108 informal questionnaires distributed, 26 were returned. Of those returned, 22 respondents indicated LCA is currently taught within a course or is planned as a part of a course being developed. Of the remaining respondents, the reasons given for not teaching LCA were (1) that LCA is outside the scope of current course work, (2) that the respondent’s status had changed (a change in university, on leave from teaching), or lack of background in LCA.

Toward the Estimation of Liquid Crystal Display Materials for Waste Management and Other Assessments

A review of the materials used in liquid crystal display (LCD) monitors is followed by the development of a parametric model for the quantification of material masses from waste monitors. The model uses diagonal length as an input which is first translated into a range of screen areas using viewing area aspect ratios. Next, the model divides LCD monitor components into those that are scaled by the screen area and those that are not, and estimates the masses of materials based on when components are removed in a materials recovery facility. Model results are presented as the coefficients of linear functions which allow specific material quantities to be estimated for each diagonal length. Overall the screen area LCD material estimation model results compare well with the published data in terms of both unit masses and individual material masses. The model is applied in an example characterization of material stream purity and suggested for use in materials flow analysis, life cycle assessment and in the quantification of the materials management needs of a certain recycler or in a certain region or country.

Estimating regional material flows for LCDs Proceedings of the IEEE international symposium on electronics and the environment ISEE (May 2008)

As LCD monitors increasingly enter the e-waste stream, there is a need to better understand what recyclers might expect in terms of what they will receive and what materials they will need to manage. Here, we identify materials used in the production of key subassemblies, and note uncertainties in the composition of the LCD assembly, film set (comprised of the reflection foil, light guide, prism foil, diffuser, and the brightness enhancement film), and the backlight assembly. Next, we quantify the range of U.S. flows of LC assembly and film set materials and the mercury in the backlight assembly, on the basis of the range of screen diagonals for portable PCs, PC flat screens, and TV flat screens. Finally, we considered computer use statistics presented by the U.S. Census and data on the location of U.S. e-waste and automotive mercury switch recovery programs as a first step in understanding regional preparedness, noting opportunities for improvements in all aspects of our analysis.