1231 of 3
CiteExportLink to record
Permanent link

Direct link
Cite
Citation style
  • apa
  • ieee
  • modern-language-association-8th-edition
  • vancouver
  • Other style
More styles
Language
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Other locale
More languages
Output format
  • html
  • text
  • asciidoc
  • rtf
Advancing the life cycle energy optimisation methodology
KTH, School of Engineering Sciences (SCI), Centres, VinnExcellence Center for ECO2 Vehicle design. KTH, School of Engineering Sciences (SCI), Engineering Mechanics, Vehicle Engineering and Solid Mechanics.ORCID iD: 0000-0002-1848-7924
2019 (English)Licentiate thesis, comprehensive summary (Other academic)
Abstract [en]

The Life Cycle Energy Optimisation (LCEO) methodology aims at finding a design solution that uses a minimum amount of cumulative energy demand over the different phases of the vehicle's life cycle, while complying with a set of functional constraints. This effectively balances trade-offs, and therewith avoids sub-optimal shifting between the energy demand for the cradle-to-production of materials, operation of the vehicle, and end-of-life phases. This work further develops the LCEO methodology and expands its scope through three main methodological contributions which, for illustrative purposes, were applied to a vehicle sub-system design case study.

An End-Of-Life (EOL) model, based on the substitution with a correction factor method, is included to estimate the energy credits and burdens that originate from EOL vehicle processing. Multiple recycling scenarios with different levels of assumed induced recyclate material property degradation were built, and their impact on the LCEO methodology's outcomes was compared to that of scenarios based on landfilling and incineration with energy recovery. The results show that the inclusion of EOL modelling in the LCEO methodology can alter material use patterns and significantly effect the life cycle energy of the optimal designs.

Furthermore, the previous model is expanded to enable holistic vehicle product system design with the LCEO methodology. The constrained optimisation of a vehicle sub-system, and the design of a subset of the processes which are applied to it during its life cycle, are simultaneously optimised for a minimal product system life cycle energy. In particular, a subset of the EOL processes' parameters are considered as continuous design variables with associated barrier functions that control their feasibility. The results show that the LCEO methodology can be used to find an optimal design along with its associated ideal synthetic EOL scenario. Moreover, the ability of the method to identify the underlying mechanisms enabling the optimal solution's trade-offs is further demonstrated.

Finally, the functional scope of the methodology is expanded through the inclusion of shape-related variables and aerodynamic drag estimations. Here, vehicle curvature is taken into account in the LCEO methodology through its impact on the aerodynamic drag and therewith its related operational energy demand. In turn, aerodynamic drag is considered through the estimation of the drag coefficient of a vehicle body shape using computational fluid dynamics simulations. The aforementioned coefficient is further used to estimate the energy required by the vehicle to overcome aerodynamic drag. The results demonstrate the ability of the LCEO methodology to capitalise on the underlying functional alignment of the structural and aerodynamic requirements, as well as the need for an allocation strategy for the aerodynamic drag energy within the context of vehicle sub-system redesign.

Overall, these methodological developments contributed to the exploration of the ability of the LCEO methodology to handle life cycle and functional trade-offs to achieve life cycle energy optimal vehicle designs.

Abstract [sv]

Livscykelenergioptimerings-metodologin (LCEO) syftar till att hitta en designlösning som använder en minimal mängd av energi ackumulerat över de olika faserna av en produkts (i detta arbete i formen av ett fordon) livscykel, samtidigt som den uppfyller en förutbestämd uppsättning funktionella begränsningar. Genom detta kan avvägningar balanseras effektivt, och därmed undviks suboptimala förskjutningar mellan energibehovet för vagga-till-produktion av material, fordonets användningsfas samt hantering av det uttjänta fordonet, på engelska kallad End-Of-Life (EOL). Detta arbete vidareutvecklar LCEO-metodologin och utvidgar dess omfattning genom tre huvudsakliga metodologiska bidrag, som, för illustrativa syften, har applicerats på en fallstudie av ett fordons sub-systemdesign.

En EOL-modell baserad på substitution med korrigeringsfaktorer, är inkluderad för att uppskatta energikrediter och bördor som härrör från hanteringen av det uttjänta fordonet. Flera olika scenarier som beskriver återvinning med olika nivåer av antagen degradering av egenskaper hos de återvunna materialen har definierats, och deras respektive LCEO utfall har jämförts med motsvarande resultat för scenarier baserade på deponering och förbränning med energiåtervinning. Resultaten visar att införandet av en EOL-modell i LCEO-metodologin kan ändra flöden och mönster kring materialanvändning och har en signifikant påverkan på den totala livscykelenergin i de optimala fordonsdesignen

Då valet av EOL-modell har signifikans för LCEO utfallet, har de föregående, statiska modellerna kompletterats med en utvidgning mot en mer holistisk systemstudie utifrån LCEO. I denna utvidgning studeras frågor kring optimerade produktsystem, framförallt avseende en delmängd av EOL processernas parametrar som har inkluderats i form av kontinuerliga designvariabler med antagna barriärfunktioner som modellerar deras genomförbarhet. Resultaten visar att LCEO kan användas för att finna den optimala designen av en fordonskomponent tillsammans med dess associerade, ideala, syntetiska EOL-scenario. Dessutom demonstreras metodens förmåga att identifiera de underliggande mekanismer som möjliggör den optimala lösningens avvägningar.

För att utöka komplexiteten i de ansatta funktionella begränsningarna har även form-relaterade variabler och aerodynamiska motståndsberäkningar tagits med. I det här fallet används krökningen på den studerade fordonskomponenten som ytterligare en variabel i LCEO analyser, med dess inverkan på det aerodynamiska motståndet och i och med detta variationer i användningsfasens energibehov. I detta fallet har det aerodynamiska motståndet tagits med i analysen genom uppskattning av motståndskoefficienten av en fordonskomponent framtagen genom strömningsmekaniska beräkningar. Denna uppskattning används sedan för att modellera den energi som krävs av fordonet för att övervinna det aerodynamiska luftmotståndet. I detta sammanhang visas också på behovet av en strategi för allokering av den aerodynamiska motståndsenergin hos en sub-komponent i relation till helheten, när fokus ligger på design av ett sub-system hos ett fordon. Resultaten visar att LCEO beskriver den underliggande funktionella synergin mellan de ansatta strukturella och de aerodynamiska kraven.

Detta arbete bidrar till att LCEO utvecklas i flera olika avseenden som utgör väsentliga steg mot en pro-aktiv metod som kan hantera livscykel- och funktionella avvägningar i en optimal fordonsdesign ur ett livscykelenergiperspektiv.

Place, publisher, year, edition, pages
Stockholm: KTH Royal Institute of Technology, 2019. , p. 76
Series
TRITA-SCI-FOU ; 2019:60
Keywords [en]
life cycle energy, vehicle design, optimisation, functional conflicts
Keywords [sv]
livscykelenergi, fordonsdesign, optimering, tvär-funktionella konflikter
National Category
Vehicle Engineering Environmental Engineering Design
Research subject
Vehicle and Maritime Engineering
Identifiers
URN: urn:nbn:se:kth:diva-265556ISBN: 978-91-7873-408-5 (print)OAI: oai:DiVA.org:kth-265556DiVA, id: diva2:1378794
Presentation
2020-01-24, E2, Lindstedtsvägen 3, Stockholm, 10:00 (English)
Opponent
Supervisors
Available from: 2019-12-18 Created: 2019-12-13 Last updated: 2019-12-19Bibliographically approved
List of papers
1. The inclusion of End-Of-Life modelling in the Life Cycle Energy Optimisation methodology
Open this publication in new window or tab >>The inclusion of End-Of-Life modelling in the Life Cycle Energy Optimisation methodology
Show others...
(English)Manuscript (preprint) (Other academic)
Abstract [en]

In this work, an End-Of-Life (EOL) model is included in the Life Cycle Energy Optimisation (LCEO) methodology to account for the energy burdens and credits stemming from a vehicle’s EOL processing phase and balance them against the vehicle’s functional requirements and production and use phase energies. The substitution with a correction factor allocation method is used to model the contribution of recycling to the EOL phase’s energy. The methodology is illustrated through the optimisation of the design of a simplified vehicle sub-system. For the latter, multiple recycling scenarios with varying levels of assumed recycling induced material property degradation were built, and their impact on the vehicle sub-system’s optimal solutions was compared to that of scenarios based on landfilling and incineration with energy recovery. The results show that the inclusion of EOL modelling in the LCEO methodology can significantly alter material use patterns thereby effecting the life cycle energy of the optimal designs. Indeed, the vehicle sub-system’s optimal designs associated with the recycling scenarios are on average substantially heavier, and less life cycle energy demanding, than their landfilling or incineration with energy recovery-related counterparts.

Keywords
End-of-Life modelling, life cycle energy optimisation, vehicle design, credit allocation, recycling
National Category
Vehicle Engineering Environmental Engineering Design
Identifiers
urn:nbn:se:kth:diva-265554 (URN)
Note

QC 20191218

Available from: 2019-12-13 Created: 2019-12-13 Last updated: 2019-12-18Bibliographically approved
2. Towards holistic energy-efficient vehicle product system design: The case for a penalized continuous end-of-life model in the life cycle energy optimisation methodology
Open this publication in new window or tab >>Towards holistic energy-efficient vehicle product system design: The case for a penalized continuous end-of-life model in the life cycle energy optimisation methodology
Show others...
2019 (English)In: 22nd International Conference on Engineering Design, ICED19, Cambridge University Press, 2019, Vol. 1, p. 2901-2910Conference paper, Published paper (Refereed)
Abstract [en]

The Life Cycle Energy Optimisation (LCEO) methodology aims at finding a design solution that uses a minimum amount of cumulative energy demand over the different phases of the vehicle's life cycle, while complying with a set of functional constraints. This effectively balances trade-offs, and therewith avoids sub-optimal shifting between the energy demand for the cradle-to-production of materials, operation of the vehicle, and end-of-life phases. The present work describes the extension of the LCEO methodology to perform holistic product system optimisation. The constrained design of an automotive component and the design of a subset of the processes which are applied to it during its life cycle are simultaneously optimised to achieve a minimal product system life cycle energy. A subset of the processes of the end-of-life phase of a vehicle’s roof are modelled through a continuous formulation. The roof is modelled as a sandwich structure with its design variables being the material compositions and the thicknesses of the different layers. The results show the applicability of the LCEO methodology to product system design and the use of penalisation to ensure solution feasibility.

Place, publisher, year, edition, pages
Cambridge University Press, 2019
National Category
Environmental Engineering Vehicle Engineering Design
Identifiers
urn:nbn:se:kth:diva-248606 (URN)10.1017/dsi.2019.297 (DOI)
Conference
22nd International Conference on Engineering Design, ICED19
Note

QC 20190617

Available from: 2019-04-09 Created: 2019-04-09 Last updated: 2019-12-13Bibliographically approved
3. The inclusion of vehicle shape and aerodynamic drag estimations within the life cycle energy optimisation methodology
Open this publication in new window or tab >>The inclusion of vehicle shape and aerodynamic drag estimations within the life cycle energy optimisation methodology
Show others...
2019 (English)In: Procedia CIRP, ISSN 2212-8271, E-ISSN 2212-8271, Vol. 84, p. 902-907Article in journal (Refereed) Published
Abstract [en]

The present work describes a widening of the scope of the Life Cycle Energy Optimisation (LCEO) methodology with the addition of shape-related design variables. They describe the curvature of a vehicle which impacts its aerodynamic drag and therewith its operational energy demand. Aerodynamic drag is taken into account through the estimation of the drag coefficient of the vehicle body shape using computational fluid dynamics simulations. Subsequently, the aforementioned coefficient is used to calculate the operational energy demand associated with the vehicle. The methodology is applied to the design of the roof of a simplified 2D vehicle model which is both mechanically and geometrically constrained. The roof is modelled as a sandwich structure with its design variables consisting of the material compositions of the different layers, their thicknesses as well as the shape variables. The efficacy of the LCEO methodology is displayed through its ability to deal with the arising functional conflicts while simultaneously leveraging the design benefits of the underlying functional alignments. On average, the optimisation process resulted in 2.5 times lighter and 4.5 times less life cycle energy-intensive free shape designs. This redesign process has also underlined the necessity of defining an allocation strategy for the energy necessary to overcome drag within the context of vehicle sub-system redesign.

Place, publisher, year, edition, pages
Elsevier, 2019
Keywords
life cycle energy optimisation; vehicle design; aerodynamic drag; functional conflicts
National Category
Vehicle Engineering Environmental Engineering Design
Identifiers
urn:nbn:se:kth:diva-223377 (URN)10.1016/j.procir.2019.04.270 (DOI)
Note

QC 20190906

Available from: 2018-02-19 Created: 2018-02-19 Last updated: 2019-12-13Bibliographically approved

Open Access in DiVA

bouchouireb2019thesis(2018 kB)30 downloads
File information
File name FULLTEXT01.pdfFile size 2018 kBChecksum SHA-512
8909b27c54e6d0bb4626cb25084fe28645992d05c123f2625a07f1ab346aeb47936c8b113f2aa2eef37bf8401d836abae3aad42474a433d4429b9e4c8c2375c1
Type fulltextMimetype application/pdf

Search in DiVA

By author/editor
Bouchouireb, Hamza
By organisation
VinnExcellence Center for ECO2 Vehicle designVehicle Engineering and Solid Mechanics
Vehicle EngineeringEnvironmental EngineeringDesign

Search outside of DiVA

GoogleGoogle Scholar
Total: 30 downloads
The number of downloads is the sum of all downloads of full texts. It may include eg previous versions that are now no longer available

isbn
urn-nbn

Altmetric score

isbn
urn-nbn
Total: 251 hits
1231 of 3
CiteExportLink to record
Permanent link

Direct link
Cite
Citation style
  • apa
  • ieee
  • modern-language-association-8th-edition
  • vancouver
  • Other style
More styles
Language
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Other locale
More languages
Output format
  • html
  • text
  • asciidoc
  • rtf