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Mike Ashby Department of Engineering University of Cambridge www.grantadesign.com/education/resources © M. F. Ashby, 2011 For reproduction guidance see.

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Presentation on theme: "Mike Ashby Department of Engineering University of Cambridge www.grantadesign.com/education/resources © M. F. Ashby, 2011 For reproduction guidance see."— Presentation transcript:

1 Mike Ashby Department of Engineering University of Cambridge © M. F. Ashby, 2011 For reproduction guidance see back page This lecture unit is part of a set created by Mike Ashby to help introduce students to materials, processes and rational selection. The Teaching Resources website aims to support teaching of materials-related courses in Design, Engineering and Science. Resources come in various formats and are aimed primarily at undergraduate education. Unit 12. Eco-selection and the Eco-audit tool Introducing students to life-cycle thinking

2 M. F. Ashby, 2011 Outline Material consumption and life-cycle Eco-audits and the audit tool Strategy for materials selection LCA - problems and solutions Exercises Resources  Text: “Materials and the Environment”, Chapters  Text: “ Materials: engineering, science, processing and design”, 2 nd Edition, Chapter 20  Text: “Materials Selection in Mechanical Design”, 4 th Edition, Chapter 16  Software: CES EduPack with Eco-Audit tool  Poster: Wall chart of Eco-properties of materials Demo

3 M. F. Ashby, 2011 Material production Concern 1: Resource consumption, dependence 96% of all material Usage 20% of Global energy

4 M. F. Ashby, 2011 Carbon to atmosphere Concern 2: Energy consumption, CO 2 emission 20% of all carbon to atmosphere

5 M. F. Ashby, 2011 The product life-cycle Landfill Combust Resources Emissions and waste Life cycle assessment (LCA )

6 M. F. Ashby, 2011 Typical LCA output Aluminum cans, per 1000 units Bauxite59kg Oil fuels148MJ Electricity1572 MJ Energy in feedstock512 MJ Water use1149kg Emissions: CO 2 211kg Emissions: CO0.2kg Emissions: NO x 1.1kg Emissions: SO x 1.8kg Particulates2.47kg Ozone depletion potential 0.2 X Global warming potential 1.1 X Acidification potential 0.8 X Human toxicity potential 0.3 X Life cycle assessment (LCA) Roll up into an “eco-indicator” ? Full LCA expensive, and requires great detail and skill – and even then is subject to uncertainty How can a designer used these data? Resource consumption Emissions inventory Impact assessment ISO series PAS 2050

7 M. F. Ashby, 2011 Design guidance vs. product assessment Product specification Concept Embodiment Detail Market need Problem statement Alternative schemes Layout and materials CAD, FE analysis, optimization, costing Production Life cycle assessment Eco – audit ability

8 M. F. Ashby, 2011 Eco-audit for design Need: Fast Eco-audit with sufficient precision to guide decision-making  Distinguish life-phases  1 resource – energy (oil equivalent) 1 emission – CO 2 equivalent Energy (MJ) Material Manufacture Transport Use Disposal EoL credit C0 2 equiv (kg) Material Manufacture Transport Use Disposal EoL credit This is the life-energy and life-CO 2 (as prescribed in ISO and PAS 2050) These are potential benefits (could be recovered at end of life)

9 M. F. Ashby, 2011 Fast eco-audit Eco-aware design: the strategy (1) The steps Analyse results, identify priorities Explore options with “What if..”s Energy (MJ) Material Manufacture Transport Use Disposal EoL credit Initial design Energy (MJ) Material Manufacture Transport Use Disposal EoL credit What if.. Different material?

10 M. F. Ashby, 2011 Fast eco-audit Eco-aware design: the strategy (2) The steps Analyse results, identify priorities Use CES to select new Materials and/or Processes Recommend actions & assess potential savings Explore options with “What if..”s Energy (MJ) Material Manufacture Transport Use Disposal EoL credit Use eco-audit to indentify design objective Minimize: material in part embodied energy CO 2 / kg Material Minimize: process energy CO 2 /kg Manufacture Minimize: mass distance transport type Transport Minimize: mass thermal loss electrical loss Use Select: non-toxic materials recyclable materials End of life Look at the first three steps

11 M. F. Ashby, 2011 The CES Eco-audit tool User interface  Bill of materials  Manufacturing process  Transport needs  Duty cycle  End of life choice User interface  Bill of materials  Manufacturing process  Transport needs  Duty cycle  End of life choice User inputs Eco database  Embodied energies  Process energies  CO 2 footprints  Unit transport energies  Recycling / combustion Eco database  Embodied energies  Process energies  CO 2 footprints  Unit transport energies  Recycling / combustion Data from CES Eco audit model Outputs (including tabular data)

12 M. F. Ashby, 2011 Typical record showing eco-properties

13 M. F. Ashby, 2011 The simple Audit tool: Levels 1, 2 and 3 Add record Eco Audit Synthesizer Options…. ^ 1. Material, manufacture and end of life ? v 2. Transport ? v 3. Use ? v 4. Report ? 1 Component 1 Cast iron 30% 2.4 Casting Recycle 1 Component 2 Polypropylene 0% 0.35 Molding Landfill HELP at each step Name Choose material from CES DB tree Enter mass Set recycle content 0 – 100% Choose process Choose end-of- life path How many?

14 M. F. Ashby, 2011 CES EduPack materials tree Material and process energy / CO 2 Component name Material Process Mass (kg) End of life Component 1 Aluminum alloys Casting 2.3 Recycle End of life options Reuse Refurbish Recycle Combust Landfill Component 2 Polypropylene Polymer molding 1.85 Landfill Component 3 Glass Glass molding 3.7 Reuse Total embodied energy Total process energy Total mass Total end of life energy Available processes Casting Forging / rolling Extrusion Wire drawing Powder forming Vapor methods

15 M. F. Ashby, 2011 Transport Transport stage Transport type Distance (km) Stage 1 32 tonne truck 350 Stage 2 Sea freight Table of transport types: MJ / tonne.km CO 2 / tonne.km Transport energy Transport CO 2

16 M. F. Ashby, 2011 Use phase – static mode Energy input and output Power rating Usage Fossil fuel to electric days per year hours per day 1.2kW Energy conversion path Fossil fuel to heat, enclosed system Fossil fuel to heat, vented system Fossil fuel to electric Fossil fuel to mechanical Electric to heat Electric to mechanical (electric motor) Electric to chemical (lead-acid battery) Electric to chemical (Lithium-ion battery) Electric to light (incandescent lamp Electric to light (LED) Total energy and CO 2 for use W kW MW hp ft.lb/sec kCal/yr BTU/yr

17 M. F. Ashby, 2011 Bottled water (100 units) Fossil to electric 0.12 kW 2 days 24 hrs/day Use - refrigeration  1 litre PET bottle with PP cap  Blow molded  Filled in France, transported 550 km to UK  Refrigerated for 2 days, then drunk Number Name Material Process Mass (kg) End of life 100 Bottles PET Molding 0.04 Recycle 100 Caps Polyprop Molding Recycle 100 Water 1.0 Transport 14 tonne truck Stage km

18 M. F. Ashby, 2011 The output: drink container The audit reveals the most energy and carbon intensive steps… … and allows rapid “What if…” Material Manufacture Transport Use End of life Carbon (kg) 100% virgin PET with recycling PET Glass ? Material Manufacture Transport Use End of life Energy (MJ) 100% virgin PET with recycling

19 M. F. Ashby, 2011 Change the materials Fossil to electric 0.12 kW 2 days 24 hrs/day Use - refrigeration  1 litre glass bottle with aluminum cap  Glass molded  Filled in France, transported 550 km to UK  Refrigerated for 2 days, then drunk Transport 14 tonne truck Stage km Number Name Material Process Mass (kg) End of life 100 Bottles PET Molding 0.04 Recycle 100 Caps Polyprop Molding Recycle 100 Water 1.0 Soda glass Glass mold 0.45 Aluminum Rolling 0.002

20 M. F. Ashby, 2011 Glass bottle replacing PET Material Manufacture Transport Use End of life Carbon (kg) 100% virgin PET with recycling Material Manufacture Transport Use End of life Energy (MJ) 100% virgin PET with recycling Material Manufacture Transport Use End of life Energy (MJ) Change of scale 100% virgin glass with recycling Material Manufacture Transport Use End of life Carbon (kg) Change of scale 100% virgin glass with recycling

21 M. F. Ashby, 2011 Use recycled PET instead of virgin? Material Manufacture Transport Use End of life Carbon (kg) 100% recycled PET with recycling 100% recycled PET with recycling Material Manufacture Transport Use End of life Energy (MJ) 100% virgin PET with recycling Material Manufacture Transport Use End of life Energy (MJ) Material Manufacture Transport Use End of life Carbon (kg) 100% virgin PET with recycling

22 M. F. Ashby, 2011 Is it practical to use recycled PET?

23 M. F. Ashby, 2011 Combust instead of recycle Material Manufacture Transport Use End of life Carbon (kg) 100% virgin PET with recycling Material Manufacture Transport Use End of life Energy (MJ) 100% virgin PET with recycling Material Manufacture Transport Use End of life Energy (MJ) 100% virgin PET with combustion Material Manufacture Transport Use End of life Carbon (kg) 100% virgin PET with combustion

24 M. F. Ashby, 2011 Ship by air freight, refrigerate 10 days Material Manufacture Transport Use Disposal Carbon (kg) 100% virgin PET with truck transport Material Manufacture Transpt Use Disposal Carbon (kg) 100% virgin PET with air freight Change of scale Material Manufacture Transpt Use Disposal Energy (MJ) Change of scale 100% virgin PET with air freight Material Manufacture Transport Use Disposal Energy (MJ) 100% virgin PET with truck transport

25 M. F. Ashby, 2011 Teaching with the CES Eco-audit tool Overview of the life cycle Shown how Eco Audit Tool works Pre-loaded projects Which life phase dominates? What could you do about it? Self-made projects  Bottled mineral water.prd  Hair dryer.prd  Electric kettle.prd  Portable space heater.prd  Family car.prd  Wind turbine.prd Pre-loaded in CES Edu 2011  Material  Recycle content  Transport mode  Transport distance  Use pattern  Electric energy mix  End of life Students can explore change of Introductory level teaching

26 M. F. Ashby, 2011 Jug kettle 2 kW jug kettle  Made SE Asia  Air freight to UK  Life: 3 years  6 minutes per day  300 days per year  3 years Use  12,000 km, air freight  250 km 14 tonne truck Transport Bill of materials and processes

27 M. F. Ashby, 2011 Eco audit: the jug kettle What do we learn?  Little gained by change of material for its own sake  Much gained by insulation – double wall with foam or vacuum  Or make hot water on the fly – only as much as needed

28 M. F. Ashby, 2011 The enhanced Audit tool: Eco Design Add record Eco Audit Synthesizer Options…. v 2. Transport ? v 3. Use ? v 4. Report ? Joining and finishing ^ 1. Material, manufacture and end of life ? Same as the simple model Machining, grinding, % removed % recovered at end of life 1 Component 1 Cast iron 30% 2.4 Casting Fine machining 10% Recycle 95% Component 1 Painting 0.55 m 2 Component 1 Welding 0.7 m Choose joining (adhesives, fastners, welding) and finishing (painting, plating, powder coating) Set parameters For advanced teaching the Enhanced Eco Audit Tool is available in the Eco Design Edition of CES EduPack

29 M. F. Ashby, 2011 So what? Tool 1. Eco-audits allows students to implement quick, approximate “portraits” of energy / CO 2 character of products. CES has two tools-sets to help explore the materials dimension of environmental design Tool 2. Selection strategies allows selection to re-design products to meet eco-criteria, using systematic methods They allow fast audits and systematic materials selection for redesign

30 M. F. Ashby, 2011 Lecture Unit Series These PowerPoint lecture-units are on the Teaching Resource Website Each frame of each unit has explanatory notes. You see them by opening the PowerPoint slide in Notes view (View – Notes pages) or by clicking this icon in the bottom toolbar of PowerPoint

31 M. F. Ashby, 2011 Also Available for Sustainability Exercises with Worked Solutions Other Lecture Units White Papers Interactive selection case studies Webinar recording Poster Sample Eco Audit Project Files Links to other good resource sites Eco Indicator Database On the topics of: Eco Design & Eco Audits Low Carbon Power Systems

32 M. F. Ashby, M. F. Ashby, 2011 Granta’s Teaching Resources Website aims to support teaching of materials-related courses in Engineering, Science and Design. The resources come in various formats and are primarily aimed at undergraduate students. This resource is one of 23 lecture units created by Professor Mike Ashby. The website also contains resources donated by faculty at the 800+ universities and colleges worldwide using Granta’s CES EduPack. The teaching resource website contains both resources that require the use of CES EduPack and those that don’t. Some of the resources, like this one, are open access. Author Professor Mike Ashby University of Cambridge, Granta Design Ltd. Reproduction This work is licensed under a Creative Commons Attribution-NonCommercial-ShareAlike 3.0 Unported License. Please make sure that Mike Ashby and Granta Design are credited on any reproductions. You cannot use this resource for any commercial purpose. The Granta logo, the Teaching Resources logo and laptop image and the logo for the University of Cambridge are not covered by the creative commons license. Accuracy We try hard to make sure these resources are of a high quality. If you have any suggestions for improvements, please contact us by at


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