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PEOPLE@HES-SO – Directory and Skills inventory
PEOPLE@HES-SO – Directory and Skills inventory

PEOPLE@HES-SO
Directory and Skills inventory

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Lasvaux Sébastien

Lasvaux Sébastien

Adjoint scientifique

Main skills

Funding & coord. of R&D projects

Life Cycle Assessment (LCA)

LCA of materials and tech systems

Building LCA

Building energy simulation

Decision making tool

  • Contact

  • Teaching

  • Research

  • Publications

  • Conferences

  • Portfolio

Main contract

Adjoint scientifique

Phone: +41 24 557 61 87

Desktop: S128a

Haute école d'Ingénierie et de Gestion du Canton de Vaud
Route de Cheseaux 1, 1400 Yverdon-les-Bains, CH
HEIG-VD
Institute
IE - Institut des énergies
BSc HES-SO en Energie et techniques environnementales - Haute école d'Ingénierie et de Gestion du Canton de Vaud

Ongoing

Ecobilan paramétré des pompes à chaleur pour la décarbonation des bâtiments
AGP

Role: Main Applicant

Description du projet : L'objectif du projet LCA-PAC est d'approfondir les émissions de gaz à effet de serre (GES) sur le cycle de vie des pompes à chaleur (PAC) utilisées dans les bâtiments. Croisant collecte de données in-situ sur les caractéristiques des PAC en fonctionnement et modèle paramétré d'écobilan tenant compte des paramètres influents et variables, il contribue à améliorer l'évaluation des stratégies de décarbonation du chauffage et de la production d'eau chaude sanitaire du parc existant. Appliqués à différentes échelles d'analyse et selon différents horizons temporels (retours d'expérience ex-post et vision plus prospective), cette étude permet de déterminer les gains écologiques effectifs d'une installation spécifique en prenant en compte les effets d'échelle, les taux de fuites de réfrigérant, les actions de maintenance, la consommation d'électricité selon différentes configurations de PAC, sources froides et typologies de bâtiments pour aller vers le zéro net dans le cycle de vie des bâtiments d'ici 2050.

Research team within HES-SO: Duret Alexis , Da Riva Enrico , Lasvaux Sébastien , Frossard Mija , Demonchy Gauthier

Durée du projet: 01.02.2025 - 30.10.2027

Statut: Ongoing

Lowering of heat distribution temperatures, for integration of renewables and decarbonisation of multifamily buildings in dense districts
AGP

Role: Collaborator

Description du projet : As a requisite for massive integration of renewables and decarbonisation with heat pumps or district heating, the T-DROP project explores optimal combinations of targeted envelope retrofit and technical optimization of heat distribution systems to lower its temperatures. Focus is set on multifamily buildings in dense districts. An extensive set of case studies, with diverse and mixed building typologies, will be used for characterisation of building and system archetypes, for testing of prospective scenarios, as well as for disseminating recommendations at national level.

Research team within HES-SO: Périsset Blaise , Duret Alexis , Favre Didier , Lasvaux Sébastien , Jobard Xavier , Pauletta Stefano , Demonchy Gauthier

Durée du projet: 02.01.2023 - 30.09.2025

Statut: Ongoing

Solutions logistiques pour le réemploi dans la construction
AGP

Role: Co-applicant

Description du projet : Le projet consiste à assurer étudier les solutions logistiques mises en 'uvre actuellement pour le réemploi de matériaux de construction et de terres d'excavation dans le canton de Genève et à mener des projets pilote et élaborer des propositions pour de nouvelles solutions ou pour des améliorations, afin de développer l'économie circulaire par le réemploi dans la construction. Le projet mené avec la HEIG-VD bénéficie du soutien des SIG, dela FTI et de l'association Materiuum.

Research team within HES-SO: Rinquet Lionel , Lasvaux Sébastien , Frossard Mija , Demonchy Gauthier , Seraphin Benoît

Durée du projet: 01.01.2023 - 31.12.2025

Statut: Ongoing

TypoRENO-VD
AGP

Role: Co-applicant

Description du projet : Objectif du projet pilote TYPO-RENO Développer des fiches (feuille de route) pour la rénovation énergétique des bâtiments vaudois représentatifs, protégés en catégorie 2 ou 3 en collaboration avec la Direction de l'énergie (DGE-DIREN) ·et la Direction générale des immeubles et -du patrimoine (DGIP-MS). Les fiches serviront de pratique commune pour la rénovation énergétique des bâtiments à valeur patrimoniale dans ·1e canton de Vaud, ainsi que d'outils de communication vers les communes, les architectes et le grand public. Le travail est structuré en deux phases. Une phase test qui sert à mettre en place le processus. Elle permet d'ajuster et valider la méthode de travail, le gabarit et le contenu des fiches au travers d'un premier cas concret. La deuxième phase comporte l'analyse des différentes études de cas choisies et l'établissement d'une fiche de synthèse par étude de cas. ' Analyse du bâtiment existant. ' Développement d'un scénario de rénovation. ' Elaboration des détails constructifs de l'enveloppe. ' Calcul du bilan énergétique selon SIA 380/L ' Calcul de l'étiquette CECB (avant & aprés rénovation selon Lesosai). ' Possibilité d'intégration de l'énergie solaire .(intégration architecturale seule). ' Calcul du bilan environnemental (selon Lesosai). ' Chiffrage des coûts de construction (selon fiche eREN). ' Etablissement d'une.fiche récapitulative avec l'évaluation des résultats.

Research team within HES-SO: Périsset Blaise , Sciboz Yanaelle , Rime Jean-Luc , Favre Didier , Perrelet Théo , Lasvaux Sébastien , Bitzi Raphaël , Gaudard Jean-François , Gatard Maëlle , Deregis Maxime , Schwab Stefanie

Partenaires académiques: Canton de Vaud; FR - EIA - Institut TRANSFORM; Administration communale Bas-Inthyamon; Patrimoine Suisse; iE; Schwab Stefanie, FR - EIA - Institut TRANSFORM

Durée du projet: 01.09.2021 - 31.12.2025

Statut: Ongoing

Case studies Romandie: strategies and potentials of temperature reduction on existing district heating networks
AGP

Role: Collaborator

Requérant(e)s: iE

Description du projet : While reduction of DH (district heating) temperature is a priority for integration of renewable heat, it is conditioned by the temperature level of the individual substations. This issue is of particular concern for existing buildings, where distribution temperatures are known to be high, and where corrective actions within inhabited spaces is of particular complexity. Several techniques for temperature reductions at substation level have been proposed or are currently under investigation, but their actual implementation on existing DH substations depends to a large extent on pre-existing conditions. Furthermore, the actual benefit of temperature reduction at the level of the DH network, as well as interaction between temperature reduction strategies and other energy policy measures, need to be analyzed on specific case studies. Within this WP, these issues will be tackled by means of case studies on existing DH systems, in urban and rural context, requiring close collaboration with our cooperation partners.

Research team within HES-SO: Duret Alexis , Lasvaux Sébastien , Jobard Xavier , Robert Alain , Masset Olivier

Partenaires professionnels: iE

Durée du projet: 01.05.2021 - 31.12.2025

Url of the project site: https://www.sweet-decarb.ch

Statut: Ongoing

Completed

Identification of the potential to reduce the environmental impacts through the reuse of materials for Swiss buildings (Reuse-LCA)
AGP

Role: Main Applicant

Description du projet : The main focus of the Reuse-LCA project is to analyze the potential environmental gains (non-renewable energy and GHG emissions) that the reuse of materials entails, in buildings. Several design alternatives of pilot buildings (new constructions and energy-related refurbishments) situated in different regions in Switzerland are studied in detail. Thus, along with the financial costs of the reuse, the potential environmental gains of reuse, combined with other low-carbon strategies are, also, evaluated.

Research team within HES-SO: Périsset Blaise , Citherlet Stéphane , Favre Didier , Lasvaux Sébastien , Goulouti Kyriaki , Frossard Mija , Demonchy Gauthier

Partenaires académiques: iE

Partenaires professionnels: CPEG; DGIP Direction générale immeubles et du patrimoine; Immobilien Basel-Stadt; Axa Investment Managers ; Losinger Marazzi AG; SBB AG

Durée du projet: 01.01.2021 - 31.01.2025

Statut: Completed

Revue critique ACV projet de recherche ADEME SAND
AGP

Role: Main Applicant

Description du projet : Revue critique ACV dans le cadre d'un projet de recherche ADEME portant sur le développement de sables de boues de béton et de sable de bétons de démolition

Research team within HES-SO: Lasvaux Sébastien , Frossard Mija

Partenaires académiques: iE

Durée du projet: 01.05.2023 - 31.12.2024

Statut: Completed

S-DSM - Sustainable Demand Side Management for a low Carbon Footprint operation of Buildings
AGP

Role: Collaborator

Description du projet : With technologies to achieve the Energy Strategy 2050, the energy demand profile of buildings is changing. However, we are still dependent on electrical energy from the grid. The carbon footprint of this grid not only fluctuates seasonally, but also strongly within a day. Here, this carbon footprint is applied to a predictive controller at the DSO and energy contractor level into the building operation of two buildings; the K3 complex in Wallisellen and the NEST demonstrator at Empa.

Research team within HES-SO: Citherlet Stéphane , Lasvaux Sébastien , Jobard Xavier , Goulouti Kyriaki , Frossard Mija

Durée du projet: 01.01.2021 - 31.12.2024

Publications liées:

  • EcoDynElec : Open Python package to create historical profiles of environmental impacts from regional electricity mixes

Statut: Completed

Réemploi des matériaux de construction, état des lieux sur les défis logistiques.
AGP

Role: Collaborator

Requérant(e)s: HEPIA inPACT, Rinquet Lionel, HEPIA inPACT

Description du projet : La déconstruction et les déchets de chantier représentent de véritables mines urbaines non exploitées qui génèrent en Suisse environ 17MT/an de matériaux de déconstruction et 57MT/an de matériaux d'excavation qui finissent pour l'immense majorité en décharge ou incinéré. Peu sont actuellement recyclés et encore moins réutilisés. Cette pression environnementale épuise les ressources naturelles, engorge les décharges existantes et représente indirectement une surconsommation d'énergie grise et de gaz à effet de serre pour fabriquer de nouveaux matériaux. Cela rend nécessaire la valorisation des matériaux de déconstruction et des déchets de chantier, mais le réemploi à l'échelon local, qui existe actuellement à l'état expérimental se heurte aux intérêts des fabricants de matériaux et aux habitudes bien ancrées chez les acteurs du marché. Il représente cependant un potentiel énorme pour accompagner la transition environnementale et aller dans le sens d'une économie circulaire dans le domaine de la construction.

Research team within HES-SO: Citherlet Stéphane , Rinquet Lionel , Lasvaux Sébastien , Cardinale Luca , Frossard Mija , Demonchy Gauthier , Seraphin Benoît

Partenaires académiques: HEPIA inPACT; iE; Rinquet Lionel, HEPIA inPACT

Durée du projet: 31.10.2022 - 20.12.2024

Statut: Completed

Net-zero GHG Emissions in the Building Area ' Bottom-up Approach (F2); Netto-Null Treibhausgasemissionen im Gebäudebereich ' NN-THGG_F2
AGP

Role: Co-applicant

Requérant(e)s: FR - EIA - Institut ENERGY, Jusselme Thomas, FR - EIA - Institut ENERGY

Description du projet : The Federal Government promotes basic and applied research, and the research-oriented development of novel energy technologies, especially in the areas of energy savings, efficient energy use, transmission and storage of energy and the use of renewable sources of energy. On 23 December 2022 (revised on 2 June 2023) the HEIA-FR / Energy and iTEC submitted an application at the Swiss Federal Office of Energy (SFOE) for financial support of the project «Net-zero GHG Emissions in the Building Area ' Bottom-up Approach (F2); Netto-Null Treibhausgasemissionen im Gebäudebereich ' NN-THGG_F2». This project has the following content: Net Zero is the answer, but what was the question? How can we build and renovate Swiss buildings so that they sustain life and well-being of future generations? In this project, we want to assess current practices to build and renovate buildings, in order to highlight solutions which are technically and economically feasible. We will model existing buildings with different greenhouse gas accounting methodologies and consider various future scenarios in order to reach a robust comparison between buildings. In particular, we will look at built buildings using biobased and reused/recycled materials or building components as well as new advanced and alternative construction materials. The components of the different studied buildings will then be integrated in the building stock model done by F1.

Research team within HES-SO: Périsset Blaise , Favre Didier , Zwicky Daia , Lasvaux Sébastien , Jusselme Thomas , Priore Yasmine , Schulthess Lucile , Maillard Philippe , Frossard Mija , Cau Sonia Anselmina

Partenaires académiques: PSI; FR - EIA - Institut ENERGY; ETH Zürich - Chair of Sustainable Construction ; iE; Jusselme Thomas, FR - EIA - Institut ENERGY

Durée du projet: 01.07.2023 - 30.11.2024

Statut: Completed

Solar energy neighborhoods ' Optimal design and operation of heat, cold and electricity supply on the neighborhood scale
AGP

Role: Collaborator

Description du projet : This project aims to develop smart planning methods and control strategies for high-performance solar neighborhoods. The supply with heat, cold and electricity of such neighborhoods shall make optimal use of solar energy technologies, storage solutions, and the interconnection of the buildings via electrical and thermal grids. A special focus is on the winter heat supply, and the search for effi-cient alternatives to air/water and geothermal heat pump systems. Exploiting synergies and sector coupling at the neighborhood scale will allow to reduce the carbon-intensive winter electricity de-mand and to provide a high load and production flexibility towards the electricity grid. The technical approach is the development of efficient computational models that allow a) to com-pare a large number of system variants in the design phase with regard to different objective func-tions (costs, emissions, grid flexibility) and b) to realize model-predictive control strategies on a neighborhood scale.

Research team within HES-SO: Duret Alexis , Lasvaux Sébastien , Pham Stéphanie , Capezzali Massimiliano , Fesefeldt Marten , Jobard Xavier , Clot Nathalie , Goulouti Kyriaki , Pauletta Stefano , Frossard Mija

Partenaires académiques: SPF Institut für Solartechnik

Partenaires professionnels: ponzio solar SA

Durée du projet: 01.11.2021 - 30.11.2024

Statut: Completed

OPTIM-EASE - Optimisation de la gestion énergétique d'ensemble de bâtiments incluant les impacts environnementaux et le couplage sectoriel
AGP

Role: Collaborator

Description du projet : Le concept énergétique optimal d'un groupe de bâtiments est différent de la somme des concepts optimaux des bâtiments considérés séparément. Le projet OPTIM-EASE développe un cadre méthodologique permettant l'optimisation énergétique de groupes de bâtiments en utilisant leurs synergies. En comparant la solution optimale d'un groupe de bâtiments avec la somme des solutions optimales des bâtiments individuels, les gains économiques et environnementaux de l'agrégation de bâtiments sont caractérisés.

Research team within HES-SO: Wagner Guy , Duret Alexis , Loperetti Murielle , Lasvaux Sébastien , Pham Stéphanie , Capezzali Massimiliano , Fesefeldt Marten , Jobard Xavier , Clot Nathalie , Goulouti Kyriaki , Pauletta Stefano , Frossard Mija , Demonchy Gauthier

Partenaires professionnels: Helion Solar Ouest SA; Swissolar; VSG Verband der Schweiz. Gasindustrie; Powerloop - Schweizerischer Fachverband

Durée du projet: 01.02.2021 - 31.10.2023

Statut: Completed

OPTIM-EASE - Optimisation de la gestion énergétique d'ensemble de bâtiments incluant les impacts environnementaux et le couplage sectoriel, financement FOGA
AGP

Role: Collaborator

Requérant(e)s: iE

Description du projet : Le concept énergétique optimal d'un groupe de bâtiments est différent de la somme des concepts optimaux des bâtiments considérés séparément. Le projet OPTIM-EASE développe un cadre méthodologique permettant l'optimisation énergétique de groupes de bâtiments en utilisant leurs synergies. En comparant la solution optimale d'un groupe de bâtiments avec la somme des solutions optimales des bâtiments individuels, les gains économiques et environnementaux de l'agrégation de bâtiments sont caractérisés. il s'agit, ici du financement accordé par le FOGA pour étudier spécifiquement dans le cadre du projet OPTIM-EASE, les aspect liés au gaz renouvelable: - Quantifier la contribution du gaz renouvelable au virage énergétique suisse en réduisant l'impact environnemental de la demande énergétique des groupes de bâtiments (thermique et électrique) - Développement de systèmes multi-énergie décentralisés pour des groupes de bâtiments comprenant des appareils fonctionnant au gaz renouvelable (cogénération, chaudière à gaz à haut rendement, petit réseau de chauffage urbain, etc.) - Identification des options les plus appropriées pour l'intégration du gaz renouvelable dans le concept énergétique via des méthodes d'optimisation multi-objectif, y compris la minimisation des coûts et de l'impact environnemental

Research team within HES-SO: Wagner Guy , Duret Alexis , Loperetti Murielle , Lasvaux Sébastien , Pham Stéphanie , Capezzali Massimiliano , Bürer Mary Jean , Fesefeldt Marten , Jobard Xavier , Goulouti Kyriaki , Frossard Mija

Partenaires académiques: Fachhochschule Ostschweiz; iE

Durée du projet: 31.10.2023 - 31.10.2023

Statut: Completed

Begleitgruppe Bilanzierung von Negativemissionstechnologien (NET) im Bauwesen
AGP

Role: Main Applicant

Description du projet : Participation en tant qu'expert écobilan au comité de suivi du projet "Bilanzierung von Negativemissionstechnologien (NET) im Bauwesen" de la Ville de Zürich

Research team within HES-SO: Lasvaux Sébastien

Partenaires académiques: iE

Durée du projet: 01.12.2022 - 30.06.2023

Statut: Completed

Plateforme intégrée d'aide à la rénovation énergétique des bâtiments à caractère architectural et patrimonial notables (HISTO-RENO)
AGP

Role: Main Applicant

Description du projet : Le projet Histo-Reno vise à développer une plate-forme transfrontalière intégrée d'aide à la rénovation des centres urbains historiques afin de réduire la pollution locale liée à la demande énergétique des bâtiments patrimoniaux. L'angle d'étude concerne le bâti existant à caractère architectural et patrimonial notable. Pour ce faire, le projet propose de développer une plate-forme transfrontalière reposant sur un système d'information géographique (SIG) intégrant les différents moyens d'aide à la rénovation du bâti ancien en zone urbaine. Cette plate-forme, développée en lien étroit avec les entreprises et collectivités locales, assurera une cohérence avec les besoins opérationnels du terrain. Elle permettra de développer les compétences locales dans le domaine et complètera les outils pour un aménagement durable et intégré des communes. La plate-forme Histo-Reno permettra de comparer rapidement des variantes permettant de réduire la pollution locale, en travaillant à la fois sur la réduction de la demande énergétique (amélioration de l'enveloppe thermique) et sur la fourniture d'énergie renouvelable (solution à faible impact environnemental). Deux modes d'utilisation permettront soit de capitaliser des retours d'expériences (via un mode « Consultation ») soit d'inciter, grâce un outil d'analyse, à la rénovation du bâti patrimonial (mode « Analyse »). Ces deux modes seront développés en lien étroit avec les collectivités, les propriétaires privés, les fournisseurs d'énergie et les bureaux d'ingénieurs et d'architectes afin d'assurer la pérennité de cette plate-forme à l'issue du projet.

Research team within HES-SO: Périsset Blaise , Favre Didier , Giorgi Morgane , Lasvaux Sébastien , Masset Olivier , Frossard Mija

Partenaires académiques: IGT; iE; Lasvaux Sébastien, iE

Partenaires professionnels: divers partenaires

Durée du projet: 01.02.2020 - 30.04.2023

Url of the project site: https://www.historeno.eu

Statut: Completed

NextEarthBuild ' « Une nouvelle génération d'éco-construction en terre d'excavation recyclée »
AGP

Role: Co-applicant

Requérant(e)s: FR - EIA - Institut iTEC

Description du projet : Pour rendre possible une densification urbaine durable tout en maintenant une qualité de vie acceptable, il est indispensable de repenser la manière et la matière dont les bâtiments et les aménagements sont conçus et construits. Parmi les déchets de la construction qui ne sont pas valorisés, la terre d'excavation présente le volume le plus important. Ce projet, réalisé en collaboration avec la Haute École d'Ingénierie et de Gestion du canton de Vaud (HEIG-VD), vise à faire de la terre d'excavation une nouvelle matière première qui offre une solution pragmatique et rentable au problème de la construction de bâtiments et des aménagements extérieures, tels que les parkings et les chemins piétons, souvent réalisées en béton ou en mortier silico-calcaire. La terre d'excavation pourrait donc devenir : - le composant incontournable d'une nouvelle technique de construction et de préfabrication appelée shotearth (terre projetée) ; - l'ingrédient qui rend végétalisables et auto-recyclables des nombreux aménagements extérieurs. Ce projet a pour but de développer des nouvelles manières de concevoir et de construire avec la terre d'excavation, grâce à : - l'utilisation de techniques de fabrication innovantes (projection classique, impression 3-D d'élément complexes) ; - l'optimisation des matériaux, alliant performances et éco-compatibilité ; - l'optimisation de la forme et du lien entre forme et fonction.

Research team within HES-SO: Leopold Sebastian , Galé Benjamin Claude , Delaquis Dominique , Redaelli Dario , Lasvaux Sébastien , Murith Noé , Savino Vincenzo , Bourrier Hervé , Schranz Noè , Albertoni Loran , Agustoni Amedeo , Goulouti Kyriaki , Viviani Marco , Frossard Mija

Partenaires académiques: INSIT; IGT; FR - EIA - Institut iTEC; FR - EIA - Institut SeSi

Partenaires professionnels: Pittet

Durée du projet: 01.01.2019 - 30.09.2022

Statut: Completed

Open Data Co2 60995.1 INNO-EE
AGP

Role: Collaborator

Requérant(e)s: MEI, Rappo Daniel, MEI

Description du projet : Permettre aux entreprises d'estimer leur empreinte CO2 grâce aux outils comptables qu'elles utilisent au jour le jour. Les bilans CO2 sont utiles en créant un moment durant lequel l'entreprise se questionne sur sa pratique et se fixe des objectifs. Entre ces audits, il n'y a pas d'outil simple de suivi des impacts environnementaux des activités. C'est ce problème que notre application de comptabilité CO2 propose de corriger en offrant une solution facile à intégrer qui calcule automatiquement, sur la base de valeurs reconnues, les émissions de gaz à effet de serre des activités d'une entreprise. Notre outil sera intégré comme module à la solution Open Source Odoo, largement utilisée comme ERP et logiciel de comptabilité. Dans toutes les entreprises, la comptabilité enregistre au quotidien toutes les actions, et les converti en unité monétaire, nous proposerons donc une application qui permet d'enregistrer cette comptabilité en double valeur, CHF et KG CO2, en établissant un facteur d'équivalence entre des comptes financiers, ou des articles du stock, et des KG de CO2. Des valeurs d'impact CO2 sont disponibles mais ne sont pas utilisables directement dans un tel outil (trop spécifique, complexe ou non applicable à la Suisse). Le but du projet est de créer une base de données de valeurs moyennes d'impact CO2 pour les différentes catégories les plus habituelles entrant dans un plan comptable suisse.

Research team within HES-SO: Dozot Grégory , Rappo Daniel , Citherlet Stéphane , Lasvaux Sébastien , Lecorney Stéphane , Taylor James , Favre-Lamarine Jonathan , Frossard Mija

Partenaires académiques: MEI; IGT; Rappo Daniel, MEI

Durée du projet: 01.03.2022 - 31.08.2022

Statut: Completed

Assessing Life Cycle Related Environmental Impacts Caused by Buildings (IEA-EBC Annex 72)
AGP

Role: Main Applicant

Description du projet : Ce projet contribue à la nouvelle IEA-EBC Annex 72 en fournissant l'état de l'art sur les méthodologies d'écobilans et outils de planification développés en Suisse. De même, ce projet fournira des résultats obtenus dans le cadre de projets parallèles, financés par l'OFEN et d'autres sources de financement (H2020, SNF, ') et correspondant aux sujets de l'Annex 72 (p.ex. optimisation de l'énergie grise vs énergie de fonctionnement, durées de vie d'éléments du bâtiment')

Research team within HES-SO: Citherlet Stéphane , Favre Didier , Lasvaux Sébastien , Padey Pierryves , Goulouti Kyriaki

Partenaires professionnels: IGT; IGT

Durée du projet: 15.11.2017 - 31.12.2021

Url of the project site: https://annex72.iea-ebc.org/

Publications liées:

  • Comparison of the environmental assessment of an identical office building with national methods
  • Implications of using systematic decomposition structures to organize building LCA information : a comparative analysis of national standards and guidelines- IEA EBC ANNEX 72
  • Review of visualising LCA results in the design process of buildings
  • Dataset of service life data for 100 building elements and technical systems including their descriptive statistics and fitting to lognormal distribution

Statut: Completed

Construire la densification des surfaces habitables urbaines en équilibre avec la nature
AGP

Role: Co-applicant

Requérant(e)s: FR - EIA - Institut iTEC, Zwicky Daia, FR - EIA - Institut iTEC

Description du projet : Tous pronostics démographiques prévoient un développement de plus en plus important des centres urbains. Pour lutter contre l'étalement des villes, ces dernières doivent être densifiées vers l'intérieur comme l'exige aussi la dernière LAT ' et ceci sur la base d'un stock de bâtiments urbains bien âgé. Un des moyens le plus prometteur pour densifier les villes existantes est l'augmentation de la capacité de logement des bâtiments existants par l'élargissement vers le haut, i.e. la surélévation des bâtiments. Déjà d'un point de vue des capacités de la structure du bâtiment existant, les éléments de surélévation doivent être les plus légers possibles afin de ne pas sur-solliciter la construction existante d'une façon excessive respectivement de rendre possible l'ajout d'un nombre maximal d'étages sans interventions disproportionnées sur la structure existante. Ces éléments de construction légers peuvent être réalisés en utilisant, soit des matériaux légers en dimensions usuelles, soit des matériaux de haute performance d'une densité (beaucoup) plus élevée mais permettant des dimensions très minces. Sur la base de bâtiments existants utilisés comme études de cas, des matérialisations génériques pour les éléments de surélévation sont proposées en tenant compte des exigences structurelles, thermiques, phoniques et de protection incendie en fonction de différents aménagements de surélévation. Les solutions développées sont évaluées par rapport aux impacts écologiques et économiques, à l'aide d'une bibliothèque de composants en considérant différentes combinaisons de matériaux de structure, d'isolation et de revêtements. A la multitude de combinaisons possibles de matériaux, s'en ajoutent plusieurs pour l'évaluation de l'impact du type d'aménagement intérieur et du nombre d'étages ajoutés. Ces évaluations écologique et économique permettaient d'identifier, quelles sont les solutions plus adaptées à la construction de surélévation et celles qui ne le sont pas, en considérant le type d'aménagement intérieur et le nombre d'étages ajoutés. De plus, elles permettent d'identifier les éléments prépondérants (et ainsi, à optimiser) pour l'impact écologique, en premier lieu. Les résultats montrent qu'il n'y a pas une réponse simple à la question, quelle est la matérialisation générale (« béton », « bois » etc.) la plus appropriée pour construire des surélévations. Faire des surélévations les plus hautes possibles est à priori bénéfique pour les impacts économique et écologique, mais plus elle est haute, plus il faudrait faire des compromis sur l'aménagement d'étage. Une surélévation plus haute sera aussi favorable à l'amortissement d'une rénovation énergétique de l'existant (i.e. les loyers supplémentaires grâce à la surélévation contribuent à « payer » la rénovation de l'existant). L'impact écologique se trouvent principalement dans les éléments de plancher y.c. la toiture tandis que sa distribution sur les différentes couches de l'élément varient fortement en fonction du matériau appliqué. Les couches non porteuses (i.e. second 'uvre : finitions, revêtements et parois de séparation) peuvent contribuer d'une façon très importante à l'impact écologique. Des résultats plus détaillés se trouvent dans le rapport technique final. Les résultats montrent encore qu'il n'y a pas de corrélation évidente entre le poids constructif de la surélévation et l'impact écologique. Par contre, cibler une réduction de l'impact économique est normalement au détriment de l'impact écologique, tandis qu'une augmentation des dépenses financières ne résultent normalement pas dans une réduction de l'impact écologique (au contraire). In fine, les résultats du projet permettaient de recommander des matérialisations préférentielles et de déconseiller d'autres.

Research team within HES-SO: Radu Florinel , Périsset Blaise , Rudaz Joëlle , Citherlet Stéphane , Favre Didier , Zwicky Daia , Meszes Adam Attila , Schaller Marc , Torche Jérémy , Giorgi Morgane , Lasvaux Sébastien , Runser Julie , Bernasconi Andrea , Uboldi Paride , Bourrier Hervé , Jaquerod Grégory , Goulouti Kyriaki , Schwab Stefanie

Partenaires académiques: IGT; FR - EIA - Institut iTEC; FR - EIA - Institut TRANSFORM; Zwicky Daia, FR - EIA - Institut iTEC

Durée du projet: 15.11.2018 - 31.10.2021

Statut: Completed

BIM-basierte Ökobilanzierung in frühen Entwurfsphasen (BIM-LCA)
AGP

Role: Main Applicant

Description du projet : In diesem Projekt wird eine BIM-basierte Methode entwickelt, um planungsbegleitend bereits ab den entscheidenden frühen Entwurfsphasen Ökobilanzierungen (inklusiver grauer und Be-triebsenergie) durchführen zu können. Besonderer Fokus liegt auf der einfachen Anwendbarkeit und der Visualisierung der Ergebnisse, um diese während des Entwurfsprozesses intuitiv zur Opti-mierung der ökologischen Performance des Gebäudes nutzen zu können.

Research team within HES-SO: Périsset Blaise , Garin Isabelle , Citherlet Stéphane , Favre Didier , Tschumi Gabriel , Lasvaux Sébastien , Wuhrmann Virginie , Goulouti Kyriaki

Partenaires académiques: IGT; Lasvaux Sébastien, IGT

Durée du projet: 01.01.2019 - 30.09.2021

Publications liées:

  • Implications of using systematic decomposition structures to organize building LCA information : a comparative analysis of national standards and guidelines- IEA EBC ANNEX 72
  • Review of visualising LCA results in the design process of buildings

Statut: Completed

Robust and reliable sustainability assessment for building renovation strategies (Robust-Reno-LCA)
AGP

Role: Main Applicant

Description du projet : Among all human activities, buildings are the largest energy consumers and greenhouse gases emitters, both in developed and developing countries. The building industry is therefore a key sector to mitigate climate change. With recent technological innovations certain new builds now consumer zero energy, or are even net producers of energy. However, in Europe, and more specifically in Switzerland, the building stock is made up of older buildings that have a much lower energetic performance. We therefore need to focus on energy based renovations. However it is difficult to make any robust comparisons between two renovation scenarios given the long service life of buildings and the inherent uncertainties associated with future scenarios. These uncertainties include for example: the evolution of financial costs for renovation, the external temperature evolution due to climate change, the service life of the technical equipment, the nature of the energy carriers any many more. All these uncertainties strongly affect the final environmental and economic costs as well as the effective inside comfort of renovated buildings. Our project will, through the application of new statistical methods, propose robust information on the overall impact of different renovation solutions as well as identify key parameters that need to be considered carefully in order to reduce the uncertainties of specific renovation scenarios. In particular, we will focus on environmental impact, economic costs and the indoor thermal comfort. To do so this project will implement the following three pronged strategy: 1) Adapt and apply forefront uncertainty quantification methods to the specificity of building assessment 2) Run energy simulation for various renovation scenarios on residential buildings 3) Apply detailed probabilistic LCA and LCC of renovation packages The required competences and expertise will be pooled by three research groups. Together they will provide accurate recommendation for building owners on renovation strategies considering future uncertainties.

Research team within HES-SO: Périsset Blaise , Wagner Guy , Citherlet Stéphane , Favre Didier , Lasvaux Sébastien , Padey Pierryves , Goulouti Kyriaki

Partenaires académiques: IGT; ETH Zürich; Lasvaux Sébastien, IGT

Durée du projet: 01.01.2018 - 31.08.2021

Publications liées:

  • Robust and resilient renovation solutions in different climate change scenarios
  • Statistical method to identify robust building renovation choices for environmental and economic performance
  • What is the optimal robust environmental and cost-effective solution for building renovation ? : not the usual one

Statut: Completed

Ecobilan Dynamique des Bâtiments (EcoDynBat)
AGP

Role: Collaborator

Requérant(e)s: IGT

Description du projet : Le projet EcoDynBat a pour objectif d'étudier l'effet de la variabilité temporelle lors du calcul des impacts environnementaux de l'électricité consommée dans les bâtiments. Ce travail tient compte des fluctuations temporelles 1) de la production électrique nationale, 2) des importations d'électricité, 3) des pertes réseaux et de conversions, 4) de la production d'électricité décentrali-sée et 5) de la demande d'électricité au sein du bâtiment.

Research team within HES-SO: Périsset Blaise , Duret Alexis , Citherlet Stéphane , Lasvaux Sébastien , Padey Pierryves , Capezzali Massimiliano , Jobard Xavier , Goulouti Kyriaki

Partenaires académiques: IESE; IGT

Partenaires professionnels: losinger; Amstein + Walthert

Durée du projet: 15.11.2018 - 31.07.2020

Publications liées:

  • Dynamic Life Cycle Assessment of the building electricity demand : a case study
  • Dynamic LCA of a single-family house, equipped with a micro-cogeneration unit, using a variable share of biomethane

Statut: Completed

Robust Internal Insulation for Historic Buildings (RIBuild)
AGP

Role: Collaborator

Requérant(e)s: IGT

Description du projet : RIBuild will strengthen the knowledge on how and under what conditions internal thermal insulation is to be implemented in historic buildings, without compromising their architectural and cultural values, with an acceptable safety level against deterioration and collapse of heavy external wall structures. The general objective of RIBuild is to develop effective, comprehensive decision guidelines to optimise the design and implementation of internal thermal insulation in historic buildings across the EU. RIBuild focuses on heavy external walls made of stone, brick and timber framing, as most historic buildings are made of these materials. The general objective is achieved through three main activities ' To obtain a thorough knowledge level to characterise the eligibility of the building for a deep internal thermal insulation renovation. This knowledge is obtained through screening of historic buildings, investigation of material properties and threshold values for failure ' To determine the conditions under which different internal insulation measures are reliable and affordable measures based on probabilistic modelling of the hygrothermal performance, the environmental impact and the cost/benefit ' To develop a set of comprehensive decision guidelines, which are demonstrated in a number of buildings RIBuild addresses the most difficult retrofitting measure of historic buildings: internal thermal insulation. The adaption of knowledge developed by RIBuild contributes to sustainable historic buildings with improved energy efficiency implying an easier conversion of energy supply from inefficient fossil fuels to efficient renewable energy sources. RIBuild also assesses the hygrothermal performance of the building construction, thus no collateral damage occurs; in case of failure an easy roll back of the measures is possible. The guidelines developed in RIBuild strongly support the deep and holistic retrofitting approach which historic buildings face in the coming years.

Research team within HES-SO: Périsset Blaise , Wagner Guy , Citherlet Stéphane , Favre Didier , Giorgi Morgane , Lasvaux Sébastien , Padey Pierryves , Goulouti Kyriaki

Partenaires académiques: IGT

Durée du projet: 01.01.2015 - 30.06.2020

Publications liées:

  • Energy saving potentials in historic buildings’ renovations : to which extent is the heating demand limit value (SIA 380/1) reachable and at which costs?
  • Hygrothermal assessment of historic buildings' external walls : preliminary findings from the RIBuild project for Switzerland
  • A stochastic approach to LCA of internal insulation solutions for historic buildings

Statut: Completed

Analyse des DUrées de vie des éléments de construction pour une meilleure gestion des RÉnovations du parc de bâtimEnts (DUREE)
AGP

Role: Main Applicant

Description du projet : La durée de vie d'un même élément de construction peut varier selon les sources d'information, ce qui génère un manque de consistance lors de certaines analyses (économique, écologique, etc.). Ce projet a pour but de faire une synthèse des valeurs trouvées dans la littérature suisse et étrangère, d'examiner ce qui se fait dans la pratique et d'analyser l'effet de cette variabilité sur des cas d'étude pour proposer des valeurs plus consistantes.

Research team within HES-SO: Périsset Blaise , Citherlet Stéphane , Favre Didier , Giorgi Morgane , Lasvaux Sébastien , Padey Pierryves , Goulouti Kyriaki

Partenaires académiques: IGT; ETHZ; Institut de recherches économiques (IRENE); Lasvaux Sébastien, IGT

Durée du projet: 15.11.2016 - 31.03.2019

Publications liées:

  • Dataset of service life data for 100 building elements and technical systems including their descriptive statistics and fitting to lognormal distribution
  • Service life of building elements : an empirical investigation
  • Uncertainty of building elements’ service lives in building LCA & LCC : what matters ?
  • Uncertainty and sensitivity analyses for evaluating the building element's replacement in building LCA

Statut: Completed

Seed Money Grant (LCA Swiss-Brazil)
AGP

Role: Main Applicant

Description du projet : The objective of this project is to identify the critical parameters to take into account in the development of an environmental database of construction materials for medium-economy countries. This database will be a simplified LCA with reduced data collection at manufacturing sites in order to be largely used in the construction sector with very low additional costs, allowing identify variability of environmental impact among producers of a same product.

Research team within HES-SO: Lasvaux Sébastien

Partenaires académiques: IGT; ETH Zürich - Chair of Sustainable Construction ; Universidade de São Paulo; Lasvaux Sébastien, IGT

Durée du projet: 29.01.2018 - 28.01.2019

Publications liées:

  • Primary data priorities for the life cycle inventory of construction products : focus on foreground processes

Statut: Completed

Eco-habitat à haute efficacité énergétique utilisant au mieux les ressources locales et adapté au contexte sahélien
AGP

Role: Collaborator

Requérant(e)s: IGT, Duret Alexis, IGT

Description du projet : Ce projet propose de concevoir et de développer des bâtiments écologiques adaptés au contexte sahélien en exploitant au mieux les ressources locales. Les bâtiments développés devront permettre de fournir à ses occupants un très bon niveau de confort (thermique, éclairage, ') tout en minimisant d'une part sa consommation énergétique et, d'autre part, son impact sur l'environnement. Il doit utiliser au mieux les ressources disponibles localement (éco-matériaux de construction, les ressources énergétiques tels que le solaire, ') tout en mobilisant des technologies simples, éprouvées. Ce projet a été structuré en deux axes. Un premier axe R&D durant lequel l'éco habitat sera développé et testé. Suivra un deuxième axe « renforcement des capacités » qui consistera principalement à disséminer les résultats du projet à travers deux sessions de formations continues.

Research team within HES-SO: Périsset Blaise , Garin Isabelle , Duret Alexis , Loperetti Murielle , Citherlet Stéphane , Bony Jacques , Favre Didier , Giorgi Morgane , Lasvaux Sébastien , Padey Pierryves , Eicher Sara , Zahar Skander , Guillaume Martin

Partenaires académiques: IGT; Duret Alexis, IGT

Durée du projet: 01.02.2012 - 30.09.2017

Statut: Completed

Bâti-Tech - Volet 3: Ecobilan et réduction des impacts environnementaux de la production de matériaux de construction écologiques
AGP

Role: Collaborator

Requérant(e)s: Lesbat

Description du projet : L'objectif de ce troisième volet du projet Bâti-Tech est d'effectuer un écobilan selon les règles de l'art de cinq de ces produits. Ceux-ci devraient présenter des impacts environnementaux et une consommation d'énergie primaire inférieure aux produits standards du même segment de marché.

Research team within HES-SO: Périsset Blaise , Duret Alexis , Monney Isabelle , Citherlet Stéphane , Favre Didier , Lasvaux Sébastien , Ropp Julien

Partenaires académiques: Lesbat

Durée du projet: 01.07.2013 - 30.09.2016

Publications liées:

  • Life cycle impact assessment of recycled concrete and comparison between three concrete production scenarios

Statut: Completed

2024

Dynamic simulation and life cycle analysis of a 784m2 solar thermal plant with evacuated flat plate collectors coupled to a district heating network
Scientific paper ArODES

Alexis Duret, Xavier Jobard, Stefano Pauletta, Sébastien Lasvaux, Mija Frossard, Gauthier Demonchy

Thermal Science,  2024, 28, 5 Part B, 4369-4379

Link to the publication

Summary:

One of the first solar plants in Switzerland to be integrated to a large urban district heating network has been monitored since its commissioning in 2021. Located in Geneva, this 784 m² solar field, equipped with innovative evacuated flat plate collectors, has confirmed the potential of vacuum solar collectors for industrial and district heating network applications. In 2022, the plant achieved a specific annual production of 684 kWh per m², corresponding to a 45% yearly average efficiency. A dynamic numerical model, developed under TRNSYS and validated against measurement data, allowed investigating the impact of several optimization strategies together with their economic viability. Additionally, a life cycle assessment and a life cycle cost analysis were conducted, confirming that incorporating solar heat into district heating network significantly reduces GHG emissions and non-renewable energy consumption at an energy production cost which is competitive with that of current district heating networks. These findings underscore the potential of solar thermal technology in decarbonating the thermal energy sector, notwithstanding its limited role in the current energy production arena.

Environmental savings from concrete reuse :
Scientific paper ArODES
examining the limitations and optimal practices for cutting thresholds of concrete building components for reuse

Shuyan Xiong, Mija Frossard, Sébastien Lasvaux, Edwin Zea Escamilla, Guillaume Habert

Environmental Research: Infrastructure and Sustainability,  2024, 4, 3, 035016

Link to the publication

Summary:

Concrete, a widely used construction material, presents both opportunities and challenges for promoting environmentally responsible practices. This research focuses on the concept of concrete reuse as a sustainable strategy, examining the limitations of cutting dimensions. To investigate the greenhouse gas (GHG) emissions associated with preparing concrete for reuse, a mathematical model was developed considering several factors, such as transportation emissions, energy used in cutting, and the effects of varying cutting performance and energy sources. By incorporating real-life data and connecting with industrial practices, this study establishes a screening standard to determine the minimum cutting size for concrete reuse. The results indicate that the ratio of transportation distances for the reuse case versus the new production of concrete case has an influence on the minimum cutting size for concrete reuse. Moreover, the cutting size itself significantly impacts the overall GHG emissions of the reuse strategy. We offer practical insights for industry stakeholders to optimize concrete reuse practices and effectively reduce GHG emissions. As further research explores cost-effectiveness and on-site case studies, the potential for large-scale implementation of concrete reuse has become increasingly promising. Thus, concrete reuse has emerged as a viable and effective approach to sustainable construction, provided that the minimum cutting dimensions are carefully considered.

Strategies for robust renovation of residential buildings in Switzerland
Scientific paper ArODES

Alina Galimshina, Maliki Moustapha, Alexander Hollberg, Sébastien Lasvaux, Bruno Sudret, Guillaume Habert

Nature Communications,  15, 2024, 1, 2227

Link to the publication

Summary:

Building renovation is urgently required to reduce the environmental impact associated with the building stock. Typically, building renovation is performed by envelope insulation and/or changing the fossil-based heating system. The goal of this paper is to provide strategies for robust renovation considering uncertainties on the future evolution of climate, energy grid, and user behaviors, amongst others by applying life cycle assessment and life cycle cost analysis. The study includes identifying optimal renovation options for the envelope and heating systems for building representatives from all construction periods that are currently in need of renovation in Switzerland. The findings emphasize the paramount importance of heating system replacements across all construction periods. Notably, when incorporating bio-based insulation materials, a balance emerges between environmental impact reduction and low energy operation costs. This facilitates robust, equitable, and low-carbon transformations in Switzerland and similar Northern European contexts while avoiding a carbon spike due to the embodied carbon of the renovation.

Adap­ter la don­née à la de­mande
Professional paper

Marion Cruz Absi, Lasvaux Sébastien

Tracès (revue suisse romande des techniques et cultures du bâti, partenaire de la Société suisse des Ingénieurs et Architectes (SIA)), 2024 , no  3546

Link to the publication

Summary:

L’entrée en vigueur d’un certain nombre de normes et de lois cantonales imposant le calcul de l’écobilan de bâtiments soulève de nombreuses questions. Retour sur les méthodes de calcul, les données KBOB ainsi que les outils mis à disposition.

Electricity in Buildings and LCA
Scientific paper

Lasvaux Sébastien

Buildings & Cities, 2024

Link to the publication

Summary:

The latest LCA Forum considered key issues in research and labelling regarding the representation of electricity mix in buildings’ operational electricity consumption.

Electricity consumption is an important contributor to their environmental impacts. The forum discussed the following key questions:

  • What is the current state of electricity mix modelling for construction products and buildings’ use phases?
  • How do different modelling approaches reflect and/or influence the transition of the electricity sector of a country to renewables?
  • Which electricity mix modelling approach(es) should be offered in LCA databases?

2023

EcoDynElec :
Scientific paper ArODES
Open Python package to create historical profiles of environmental impacts from regional electricity mixes

François Lédée, Pierryves Padey, Kyriaki Goulouti, Sébastien Lasvaux, Didier Beloin-Saint-Pierre

SoftwareX,  2023, vol. 23, article no. 101485

Link to the publication

Summary:

This article presents the EcoDynElec python package that creates temporal historical profiles of various potential environmental impacts for electricity mixes in different regions. The profiles are evaluated with the same electricity modeling structure that is used in life cycle assessment databases, simplifying their consistent combination in studies. The open access information from the ENTSO-E platform is used as an input that enables the creation of profiles that can reach temporal precision of 15 min for the last five years. EcoDynElec is shared to open its use in environmental studies that can be substantially affected by the temporal variability of electricity uses.

Basics and recommendations on influence of service life of building components on replacement rates and LCA-based assessment results
Report
A contribution to IEA EBC Annex 72

Lasvaux Sébastien, Kyriaki Goulouti

2023,  Uster, Switzerland : Treeze Ltd.,  36  p.

Link to the publication

Summary:

The operational and embodied GHG emissions are recorded and evaluated in a life cycle analysis of buildings. The embodied emissions are composed of the modules A1-A5 (upfront), B2-B5 and C1-C4. For reasons of simplification, concrete calculations usually focus on A1-A3, B4, C3-C4. Module B4 makes a significant contribution to the results of a building LCA. Components and systems that are either replaced very frequently or cause high environmental impacts (initially and when replaced) are important. For the modelling of B4, there are different methodological questions for which methods need to provide answers. This is the aim of this report. It particularly discusses the service lives definitions, the service life values of building components/elements and their related uncertainties and variabilities based on values found in literature as well as default values used in A72 countries. The latter values were collected based on a survey among A72 experts. This report also illustrates the consequences/ influence on the result of the variability of service life values of building components, the replacement rate calculation method and the reference study period on the basis of a case study. Finally, recommendations are provided.

Visualising LCA results in the design process
Report
A contribution to IEA EBC Annex 72

Alexander Hollberg, Benedek Kiss, Martin Röck, Bernadette Soust-Verdaguer, Aoife Houlihan Wiberg, Lasvaux Sébastien, Alina Galimshina, Guillaume Habert

2023,  Uster, Switzerland : Treeze Ltd.,  39  p.

Link to the publication

Summary:

Life Cycle Assessment (LCA) is increasingly used for decision-making in the design process of buildings and neighbourhoods. Therefore, visualisation of LCA results to support interpretation and decisionmaking becomes more important. The number of building LCA tools and the published literature has increased substantially in recent years. Most of them include some type of visualisation. However, there are currently no clear guidelines and no harmonised way of presenting LCA results. In this report, we review the current state of the art in visualising LCA results to provide a structured overview. Furthermore, we discuss recent and potential future developments. The review results show a great variety in visualisation options. By matching them with common applications of LCA we provide a structured basis for future developments. Case studies combining different kinds of visualisations within the design environment, interactive dashboards, and immersive technologies, such as virtual reality, show a big potential for facilitating the interpretation of LCA results and collaborative design processes. The overview and recommendations presented in this report provide a basis for future development of intuitive and design-integrated visualisation of LCA results to support decision-making.

Context-specific assessment methods for life cycle-related environmental impacts caused by buildings: Energy in Buildings and Communities Technology Collaboration Programme
Report
Energy in Buildings and Communities Technology Collaboration Programme - IEA EBC Annex 72

Thomas Lützkendorf, Maria Balouktsi, Rolf Frischknecht, Bruno Peuportier, Harpa Birgisdottir, Rolf André Bohnen, Maurizio Cellura, Maria Anna Cusenza, Nicolas Francart, Antonio Garcia-Martinez, Vanessa Gomes, Maristela Gomes da Silva, Juan Carlos Gomez de Cozar, Kyriaki Goulouti, Francesco Guarino, Endrit Hoxha, Lasvaux Sébastien, Carmen Llatas, Sonia Longo, Antonin Lupisek, Marina Mistretta, Pierryves Padey, Alexander Passer, Lizzie Monique Pulgrossi, Marcella R. M. Saade, Zsuzsa Szalay, Bernadette Soust-Verdaguer, Giovanni Tumminia, Xiaojin Zhang, Laetitia Delem, Tove Malmquist, Alice Moncaster, Marie Nehasilova, Damien Trigaux

2023,  Uster, Switzerland : treeze Ltd.,  190  p.

Link to the publication

Basic and recommendations on electricity mix models and their application in buildings LCA.
Report
A contribution to IEA EBC Annex 72

Bruno Peuportier, Rolf Frischknecht, Zsusza Szalay, Lasvaux Sébastien, Harpa Birgisdottir, Rolf-André Bohne, Pierryves Padey, Nicolas Francart

2023,  Uster, Switzerland : Treeze Ltd.,  115  p.

Link to the publication

Summary:

The evolution of electricity systems is one of the key issues to progress towards net zero GHG emissions, as shown in the IEA roadmap for the global energy sector1 . Because a large part of the produced electricity is consumed in buildings, and because electricity consumption is an important contributor in life cycle impacts of buildings, it is essential to properly account for the electricity system when performing a Building LCA. This document was written for method and tool developers, and policy makers (regulation). Existing (official and individual) approaches in different countries are first reviewed. Users are invited to follow the recommendations provided by the developers (e.g. certification scheme, design tools). Some of the recommendations are case specific. We propose to distinguish the following four cases:

a. Assessments against benchmarks defined by voluntary certification schemes and regulation

b. Environmental reporting of facility management companies and assessment of private lifestyles:

c. LCA in building design tools (building optimisation independent of voluntary schemes or regulation)

d. LCA in building research

These recommendations address electricity related impacts. Methodological choices should be consistent across energy sources. Thus, the following recommendations should be applied on fuels as well. For instance, if a future renewable scenario is applied for electricity production, the same level of ambition should preferably be applied for gas (future supply with biogas and/or synthetic gases produced with biogenic carbon and renewable electricity) and liquid fuels.

2022

Bio-based materials as a robust solution for building renovation :
Scientific paper ArODES
a case study

Alina Galimshina, Maliki Moustapha, Alexander Hollberg, Pierryves Padey, Sébastien Lasvaux, Bruno Sudret, Guillaume Habert

Applied Energy,  2022, vol. 316, article no. 119102

Link to the publication

Summary:

Boosting building renovation is urgently needed to achieve carbon neutrality by 2050. Building retrofit can be achieved by energy-efficient measures such as thermal insulation or replacement of a fossil heating system. Currently, conventional materials that are mostly used for envelope insulation raising the risk of a lock-in situation where measures to mitigate climate change are actually contributing to it. Bio-based materials are a promising alternative as they can be used to not only reduce the energy consumption of a building but also temporarily store carbon. To evaluate the potential benefits of such materials, life cycle assessment (LCA) and life cycle cost analysis (LCCA) are commonly used. Such assessment allows the analysis of a building over its whole life. However, considering that buildings are very long lasting systems, many associated uncertainties can affect the outcome of LCA and LCCA. To account for all the uncertainty sources and provide a robust solution for building renovation, uncertainty quantification can be applied. In this paper, we use robust optimization under uncertainties to define the most cost-effective and climate-friendly solution. We apply bio-based materials and include carbon storage calculation in the integrated LCA and LCCA. For the robust optimization, we use a novel methodology combining a well-known non-dominated sorting genetic algorithm II (NSGA-II) with surrogate modeling to lower computational cost. The methodology is applied for a case study located in Switzerland. The results show that bio-based materials provide a robust solution for building renovation but to achieve the highest reduction potential, bio-based envelope insulation should be combined with the replacement of the existing fossil heating system.

Earth plastered wall heating as a low-emitting, cost-effective and robust energy system for building renovation
Scientific paper ArODES

Alina Galimshina, Maliki Moustapha, Andreas Hollberg, Guy Wagner, Pierryves Padey, Sébastien Lasvaux, Bruno Sudret, Guillaume Habert

Bio-Based Building Materials,  2022, vol. 1, pp. 466-477

Link to the publication

Summary:

Renovation of the building stock in Europe is urgent to decrease the environmental impact from the building sector and meet the United Nations climate action goals. However, it is often hard to define a robust scenario for a renovation due to numerous uncertainties, which occur during the production, operation and end-of-life stage. One can cite the loss of performance of insulation and heating systems, the replacement time of installation or the future energy prices as well as the future climate. The replacement of oil boilers with heat pumps has shown a good performance regarding costs and greenhouse gas emissions. However, due to the flow and return temperature differences, often the current heat distribution system needs to be replaced as well, which is normally done with conventional radiators or floor heating. In this paper, we analyse a new possibility of a heat distribution system with earth plastered wall. We develop a methodology on the integrated assessment of life cycle assessment (LCA) and life cycle cost analysis (LCCA) for the renovation scenarios and adapt the analysis of the heat pump renovation solution with conventional radiators system and the earth plastered wall for two typical residential buildings located in Switzerland. Through rigorous statistical treatment, we then propagate the possible sources of uncertainty and perform the uncertainty quantification using polynomial chaos expansion to compare the distributions of two outcomes. The results show that the solution with the earth plaster has lower overall environmental impacts and costs. It has also been noticed that the solution with the earth plaster is more robust in investment cost and embodied emissions compared to the solution with the conventional radiators.

2021

Understanding the reasons behind the energy performance gap of an energy-efficient building, through a probabilistic approach and on-site measurements
Scientific paper ArODES

Pierryves Padey, Kyriaki Goulouti, Guy Wagner, Blaise Périsset, Sébastien Lasvaux

Energies,  2021, vol. 14, no. 19, article no. 6178

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Summary:

The performance gap, defined as the difference between the measured and the calculated performance of energy-efficient buildings, has long been identified as a major issue in the building domain. The present study aims to better understand the performance gap in high-energy performance buildings in Switzerland, in an ex-post evaluation. For an energy-efficient building, the measured heating demand, collected through a four-year measurement campaign was compared to the calculated one and the results showed that the latter underestimates the real heating demand by a factor of two. As a way to reduce the performance gap, a probabilistic framework was proposed so that the different uncertainties of the model could be considered. By comparing the mean of the probabilistic heating demand to the measured one, it was shown that the performance gap was between 20–30% for the examined period. Through a sensitivity analysis, the active air flow and the shading factor were identified as the most influential parameters on the uncertainty of the heating demand, meaning that their wrong adjustment, in reality, or in the simulations, would increase the performance gap.

What is the optimal robust environmental and cost-effective solution for building renovation ? :
Scientific paper ArODES
not the usual one

Alina Galimshina, Maliki Moustapha, Alexander Hollberg, Pierryves Padey, Sébastien Lasvaux, Bruno Sudret, Guillaume Habert

Energy and Buildings,  2021, vol 251, article no. 111329

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Summary:

Buildings are responsible for a large share of CO2 emissions in the world. Building renovation is crucial to decrease the environmental impact and meet the United Nations climate action goals. However, due to buildings’ long service lives, there are many uncertainties that might cause a deviation in the results of a predicted retrofit outcome. In this paper, we determine climate-friendly and cost-effective renovation scenarios for two typical buildings with low and high energy performance in Switzerland using a methodology of robust optmization. First, we create an integrated model for life cycle assessment (LCA) and life cycle cost analysis (LCCA). Second, we define possible renovation measures and possible levels of renovation. Third, we identify and describe the uncertain parameters related to the production, replacement and dismantling of building elements as well as the operational energy use in LCCA and LCA. Afterwards, we carry out a robust multi-objective optimization to identify optimal renovation solutions. The results show that the replacement of the heating system in the building retrofit process is crucial to decrease the environmental impact. They also show that for a building with already good energy performance, the investments are not paid off by the operational savings. The optimal solution for the building with low energy performance includes the building envelope renovation in combination with the heating system replacement. For both buildings, the optimal robust cost-effective and climate-friendly solution is different from the deep renovation practice promoted to decrease the energy consumption of a building.

Dataset of service life data for 100 building elements and technical systems including their descriptive statistics and fitting to lognormal distribution
Scientific paper ArODES

Kyriaki Goulouti, Didier Favre, Morgane Giorgi, Pierryves Padey, Alina Galimshina, Guillaume Habert, Sébastien Lasvaux

Data in Brief,  2021, vol. 36, article no. 107062

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Summary:

This article presents the descriptive statistics of service life data of building elements, gathered through an international, European and Swiss literature review of LCA, LCC and other sources called “Real-Estate Management sources” that include building owners, banks, insurances, associations of tenants and owners, etc. Furthermore, the properties of the fitted lognormal distribution are given. The data are structured, using a hybrid decomposition (functional decomposition, according to the eBKP-H – SN506511 and material decomposition, as well). These data and the derived statistical distributions were used in a research study, in order to quantify the uncertainty and sensitivity of the LCA and LCC output, due to the variability of the building elements’ service lives.

Environmental datasets for cement and steel rebars to be used as generic for a national context
Scientific paper ArODES

Raul Gomes, José Dinis Silvestre, Jorge de Brito, Sébastien Lasvaux

Journal of Cleaner Production,  2021, vol. 316, article no. 128003

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Summary:

The selection of the most suitable Life Cycle Assessment (LCA) databases, and corresponding elementary processes, to be used in the modelling of raw materials and related processes, is of paramount importance and decisively conditions LCA results. The NativeLCA methodology is based on the selection and/or adaptation of a coherent LCA dataset to produce each building product to be used as generic data for a national context. The aims of this paper are: to test the plausibility of Portuguese LCA datasets of raw and construction materials used in reinforced concrete structures; to confirm the coherence and usefulness of the NativeLCA methodology; and to increase the number of case studies illustrating its application that are available for the scientific and academic community. In that sense, the NativeLCA methodology is briefly summarized; available databases for construction products are presented and characterized; and two case studies (representing a full and a simplified NativeLCA methodology application) are presented and discussed. The results include coherent LCA datasets for cement and steel rebars product stage (A1-A3), based on the adaptation of available European (foreign or national) LCA datasets, that can be used as generic in LCA studies in Portugal. This paper also contributes to: the development of the NativeLCA methodology by providing examples of its application in its full and simplified versions; demonstrate that, while further efforts are needed to develop regional and sector-specific LCA databases, adapted to each national context, the NativeLCA approach can be used to consistently choose available LCA datasets to be used as generic in a national context; lead practitioners to increase the reliability of building LCA studies according to their goal and scope definition.

Potentiel d’économies de CO2 dans la rénovation
Professional paper ArODES

Didier Favre, Pierryves Padey, Sébastien Lasvaux

Bâtiment et énergie suisse 2021 : Annuaire suisse de la construction durable,  pp. 49-52

Link to the publication

Summary:

Le Laboratoire d’Energétique Solaire et de Physique du Bâtiment (LESBAT) de l’Institut de Génie Thermique (IGT) de la Haute École d’Ingénierie et de Gestion du Canton de Vaud (HEIG-VD) a développé un cadre d’analyse pour identifier les compromis sur les aspects financiers, énergétiques et climatiques de plusieurs centaines de combinaisons de scénarios de rénovation de l’enveloppe thermique des bâtiments. Une première étude de cas est présentée pour un bâtiment historique.

2020

Review of visualising LCA results in the design process of buildings
Scientific paper ArODES

Alexander Hollberg, Benedek Kiss, Martin Röck, Bernadette Soust-Verdaguer, Aoife Houlihan, Sébastien Lasvaux, Alina Galimshina, Guillaume Habert

Building and Environment,  2021, vol. 190, article no. 107530

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Summary:

Life Cycle Assessment (LCA) is increasingly used for decision-making in the design process of buildings and neighbourhoods. Therefore, visualisation of LCA results to support interpretation and decision-making becomes more important. The number of building LCA tools and the published literature has increased substantially in recent years. Most of them include some type of visualisation. However, there are currently no clear guidelines and no harmonised way of presenting LCA results. In this paper, we review the current state of the art in visualising LCA results to provide a structured overview. Furthermore, we discuss recent and potential future developments. The review results show a great variety in visualisation options. By matching them with common LCA goals we provide a structured basis for future developments. Case studies combining different kinds of visualisations within the design environment, interactive dashboards, and immersive technologies, such as virtual reality, show a big potential for facilitating the interpretation of LCA results and collaborative design processes. The overview and recommendations presented in this paper provide a basis for future development of intuitive and design-integrated visualisation of LCA results to support decision-making.

Uncertainty of building elements’ service lives in building LCA & LCC :
Scientific paper ArODES
what matters ?

Kyriaki Goulouti, Pierryves Padey, Alina Galimshina, Guillaume Habert, Sébastien Lasvaux

Building and Environment,  2020, vol. 183, article no. 106904

Link to the publication

Summary:

The existing methods of evaluating the environmental life cycle assessment (LCA) and life cycle costs (LCC) performance of a building concept have been widely used, since they offer the possibility to consider the system globally and avoid, thus, the hidden impacts. However, many studies have indicated the possible uncertainties of the input parameters and recommended the use of probabilistic methods, to deal with these issues. The current study continues towards this direction and presents a systematic way to take into account the uncertainties of the building elements’ service life within a stochastic framework, by defining the corresponding probability density functions, based on a new service life database. Applying this methodology for the calculation of the LCA & LCC for multifamily houses in Switzerland revealed that the replacement stage contributes with a share of up to 36% on the GHG emissions. Furthermore, through a global sensitivity analysis, the uncertainty on the replacement rate of six building elements was found to mainly influence the LCA & LCC uncertainty, i.e. compact façade (external insulation), windows, roofing, flooring, internal layout and ceiling covering. Finally, it was found that the reference service life of the building significantly influences the LCA and LCC uncertainty. In order to increase the reliability on the building LCA and LCC results, it is recommended to take into account probabilistically the service lives of the building elements, which mostly influence the LCA uncertainty.

Statistical method to identify robust building renovation choices for environmental and economic performance
Scientific paper ArODES

Alina Galimshina, Maliki Moustapha, Alexander Hollberg, Pierryves Padey, Sébastien Lasvaux, Bruno Sudret, Guillaume Habert

Building and Environment,  2020, vol. 183, article no. 107143

Link to the publication

Summary:

Building renovation is urgently required to decrease the energy consumption of the existing building stock and reduce greenhouse gas emissions coming from the building sector. Selecting an appropriate renovation strategy is challenging due to the long building service life and consequent uncertainties. In this paper, we propose a new framework for the robust assessment of renovation strategies in terms of environmental and economic performance of the building's life cycle. First, we identify the possible renovation strategies and define the probability distributions for 74 uncertain parameters. Second, we create an integrated workflow for Life Cycle Assessment (LCA) and Life Cycle Cost analysis (LCC) and make use of Sobol’ indices to identify a prioritization strategy for the renovation. Finally, the selected renovation scenario is assessed by metamodeling techniques to calculate its robustness. The results of three case studies of residential buildings from different construction periods show that the priority in renovation should be given to the heating system replacement, which is followed by the exterior wall insulation and windows. This result is not in agreement with common renovation practices and this discrepancy is discussed at the end of the paper.

Primary data priorities for the life cycle inventory of construction products :
Scientific paper ArODES
focus on foreground processes

Fernanda Belizario Silva, Daniel Costa Reis, Yazmin Lisbeth Mack-Vergara, Lucas Pessoto, Haibo Feng, Sérgio Almeida Pacca, Sébastien Lasvaux, Guillaume Habert, Vanderley Moacyr John

The International Journal of Life Cycle Assessment,  2020, vol. 25, pp. 980-997

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Summary:

Purpose : Life cycle assessment can support decisions for improving the environmental performance of construction products. However, the amount of data required for developing life cycle inventories limits the adoption of LCA. This work associates the interpretation of the impact results of construction products at the unit process level with a quantitative definition for the foreground and background system, for guiding primary data collection towards foreground processes that can be affected by decision-makers in the construction sector. Methods : A set of construction products commonly used in Brazil is selected, and their cradle-to-gate life cycle inventories are modeled using the ecoinvent database (version 2). Life cycle impact assessment is performed using the ReCiPe Midpoint Hierarchist method. The contribution of each process during the life cycle of construction products for each impact category is quantified. These processes are associated with economic sectors, which are classified as belonging to the foreground or background system from the perspective of the construction industry. Foreground sectors are those controlled or influenced by the construction sector and are defined based on the production share consumed by the construction value chain. The elementary flows defining each impact category are also identified. Results and discussion : Foreground processes show significant contributions to most impact results of construction products. Global warming, fine particulate matter formation, ozone formation, acidification, human carcinogenic toxicity, and terrestrial ecotoxicity are mainly caused by direct emissions and fossil fuel combustion in manufacturing processes. Land occupation for production activities contributes to land use change, while the consumption of fuels, raw materials, and water causes fossil and mineral resource scarcity and water consumption respectively. Freshwater and marine ecotoxicities and human non-carcinogenic toxicity have foreground contributions only for steel and copper products due to emissions from the landfilling of mining tails. Ionizing radiation and stratospheric ozone depletion are mostly driven by background processes. A reduced group of elementary flows covers a big share of the environmental impacts of most construction products. Conclusions : The results indicate priorities for life cycle inventory primary data collection of construction products, by focusing on foreground processes and the corresponding elementary flows that cause many of the potential embodied impacts of construction. Increasing the availability of primary data for these processes improves the reliability of LCA-based decisions in the construction sector, especially in countries which still lack local LCI databases.

A stochastic approach to LCA of internal insulation solutions for historic buildings
Scientific paper ArODES

Elisa Di Giuseppe, Marco D'Orazio, Guangli Du, Claudio Favi, Sébastien Lasvaux, Gianluca Maracchini, Pierryves Padey

Sustainability,  2020, vol. 12, no. 4, article no. 1535

Link to the publication

Summary:

Internal insulation is a typical renovation solution in historic buildings with valuable façades. However, it entails moisture-related risks, which affect the durability and life-cycle environmental performance. In this context, the EU project RIBuild developed a risk assessment method for both hygrothermal and life-cycle performance of internal insulation, to support decision-making. This paper presents the stochastic Life Cycle Assessment method developed, which couples the LCA model to a Monte-Carlo simulation, providing results expressed by probability distributions. It is applied to five insulation solutions, considering different uncertain input parameters and building heating scenarios. In addition, the influence of data variability and quality on the result is analyzed, by using input data from two sources: distributions derived from a generic Life Cycle Inventory database and “deterministic” data from Environmental Product Declarations. The outcomes highlight remarkable differences between the two datasets that lead to substantial variations on the systems performance ranking at the production stage. Looking at the life-cycle impact, the general trend of the output distributions is quite similar among simulation groups and insulation systems. Hence, while a ranking of the solutions based on a “deterministic” approach provides misleading information, the stochastic approach provides more realistic results in the context of decision-making.

2019

Service life of building elements :
Professional paper ArODES
an empirical investigation

Benjamin Volland, Mehdi Farsi, Sébastien Lasvaux, Pierryves Padey

University of Neuchâtel, Institute of Economic Research, IRENE working paper,  2019, no. 20-02

Link to the publication

Summary:

Improvements in building’s energy-efficiency hold considerable potential for decreasing energy consumption. Yet, renovations in the building stock could occur belatedly and without the coordination required for fully tapping the energy reduction potentials. In this paper, we use data from a household survey in Switzerland to analyse replacement patterns for windows, heating systems, façades and roofs. As opposed to most previous studies that assume a linear age effect, we model the renovation probability as a conditional hazard rate with a more flexible representation of age effects. We compare the renovation patterns identified by the survival analysis with the service lives determined by building norms. We find systematic deviations between the two, suggesting sub-optimal replacement in many cases, especially for the building envelope. In particular, the results point to a considerable fraction of cases, where the owners refrain from renovation far beyond the end of an element’s technical service life. Moreover, the strong differences in renovation timing across various elements could hinder the expected energy savings. We identify a number of determinants for replacement timing, in view of energy policies aiming at the promotion of energy-saving renovations in buildings.

Calcul probabiliste de la performance énergétique des bâtiments
Professional paper ArODES

Pierryves Padey, Sébastien Lasvaux, Joëlle Mastellic

Schweizer Energiefachbuch 2020,  2020, pp. 136-37

Link to the publication

Summary:

Le Laboratoire d'Energétique Solaire et de Physique du Bâtiment (LESBAT) de l'Institut de Génie Thermqiue (IGT) de la Haute École d'Ingénierie et de Gestion du Canton de Vaud (HEIG-VD) a développé une méthode de simulation énergétique probabiliste des bâtiments tenant compte de l'incertitude des valeurs standards des normes SIA (climat, performance réelle des équipements, température intérieure, etc.).

2018

Investigating transparency regarding ecoinvent users’ system model choices
Scientific paper ArODES

Marcella Ruschi Mendes Saade, Vanessa Gomes, Maristela Gomes Da Silva, Cassia Maria Lie Ugaya, Sébastien Lasvaux, Alexander Passer, Guillaume Habert

The International Journal of Life Cycle Assessment,  2019, vol. 4, pp. 1-5

Link to the publication

Summary:

Purpose : Life cycle assessment (LCA) is a data-intensive methodology; therefore, experts usually focus collection efforts on a few activities, while generic data on remaining activities are taken from databases. Even though increased availability of databases has facilitated LCA takeoff, assuring data quality is fundamental to ensure meaningful results and reliable interpretation. Methods : Ecoinvent has become a global reference for inventory data. Its current version released three impact partition modeling options—the recycled content, “allocation at the point of substitution” (APOS), and consequential models—whose adequate choice is crucial for yielding meaningful assessments. Tutorials and manuals describe the distribution algorithm that backs each system model, to ground decision-making regarding the best fit to a study’s goals. We performed a systematic literature review to investigate—within the papers published on the International Journal of LCA (IJLCA)—how transparently authors addressed the system model choices. Results and discussion : About 70% of LCA practitioners continued to use earlier versions of ecoinvent after version 3 was launched in 2013. The number of papers using versions 3.x only showed an increased growth trend 2 years later. Eighty-three papers actually adopted the newest version of the database. From those, only 29 papers clearly mentioned the adopted system model. Our SLR also suggests a trend regarding authorship profile of LCA-related studies: the number of studies conducted by practitioners aware of the intricacies of sound modeling of background and foreground data might have been surpassed by those conducted by non-LCA specialists who use LCA as a supporting tool for investigations in applied fields, and merely scratch the surface. Conclusions : Our results point to a need for a caveat: ecoinvent users must take time to understand the general concept behind each system model and practice one of the most important actions when performing an LCA—state methodological choices clearly.

2017

A review of urban metabolism studies to identify key methodological choices for future harmonization and implementation
Scientific paper ArODES

Didier Beloin-Saint-Pierre, Benedetto Rugani, Sébastien Lasvaux, Adélaïde Mailhac, Emil Popovici, Nicoleta Schiopu

Journal of Cleaner Production,  2017, vol. 163, supplement, pp. s223-s240

Link to the publication

Summary:

The concept of urban metabolism has often been used to model and analyze urban regions to provide insights on their environmental sustainability. However, no consensus exists on the assessment methods that should be used to analyze the sustainability of these complex systems. This lack of consistency prevents data sharing and comparison between most studies. Past and current publications are therefore surveyed to identify key methodological aspects that could be favored to harmonize the sustainability assessment of urban metabolism. This investigation is structured around the common aspects of environmental assessment methods that have been used for the past forty years. It suggests that a network system modeling approach, a global life-cycle perspective, and a multi-criteria assessment are strategic choices for environmental sustainability assessment. While challenging in their implementations, these choices can offer common grounds to capitalize on the knowledge brought forth by new studies. The investigation also discusses basic principles to propose developments like the use of a functional equivalent as a basis of comparison and the use of specific uncertainty assessment methods. These propositions could help to improve the clarity of future studies that tackle the question of environmental sustainability in urban metabolism.

Buildings environmental impacts' sensitivity related to LCA modelling choices of construction materials
Scientific paper ArODES

Ian-Frederic Häfliger, Viola John, Alexander Passer, Sébastien Lasvaux, Endrit Hoxha, Marcella Ruschi Mendes Saade, Guillaume Habert

Journal of Cleaner Production,  2017, vol. 156, pp. 805-816

Link to the publication

Summary:

The assessment of the environmental performance of buildings is now commonly using a life cycle approach, based on a growing number of databases and methods in Life Cycle Assessment (LCA). Recent studies have, however, highlighted the problems related to uncertainties in the LCA results. The aim of this study is to assess the sensitivity of construction materials to the different modelling choices in order to highlight their consequences at the building scale. In particular, we focused on the different modelling options in terms of database choices, system boundary definitions and replacement scenarios of building materials during the whole service life of the buildings. The assessment of uncertainties was conducted at two levels: the material or element level and the building level. The results clearly show the importance of these modelling choices. Variations on the overall assessment of buildings are significant, but the details at the material scale show that not all materials are similarly sensitive to these choices. We identified those materials that have a large contribution to the environmental impact of the buildings and which are also sensitive to different modelling choices. This can help for a better understanding of these modelling choices and can be used in upcoming regulations or public policies.

Towards guidance values for the environmental performance of buildings :
Scientific paper ArODES
application to the statistical analysis of 40 low-energy single family houses’ LCA in France

Sébastien Lasvaux, Alexandra Lebert, Fanny Achim, Francis Grannec, Endrit Hoxha, Sylviane Nibel, Nicoleta Schiopu, Jacques Chevalier

The International Journal of Life Cycle Assessment,  2017, vol. 22, pp. 657-674

Link to the publication

Summary:

Purpose : In this study, life cycle assessment (LCA) is applied to a sample of 40 low-energy individual houses for the French context in order to identify guidance values for different environmental priorities (energy and water consumption, greenhouse gases emissions, waste generation etc.). Methods : Calculation rules for the LCA derived from EeBGuide guidance and HQE Performance specific rules for the French context. Data are based on Environmental Product Declaration (EPD for the impacts related to products and technical equipment while generic data are used for energy and water processes. The LCA is defined for the entire life cycle of a building from cradle-to-grave according to NF EN 15978 standard. It includes the products and equipment implemented in the building, the different uses of energy for heating, domestic hot water, lighting, ventilation and auxiliaries, and the different uses of water consumption. Results and discussion : Results for the 40 houses showed that the average life cycle non-renewable primary energy consumption is about 37 kWh/(m2*year) while the life cycle greenhouse gases emissions are of 8.4 kg CO2-eq/(m2*year). The embodied impacts represent between 40% and 72% for the following indicators: acidification, global warming, non-renewable primary energy, and radioactive waste. The net fresh water use is mostly determined by the direct use of the water in use, and the non-hazardous waste indicator is only linked to the materials and equipment. When integrating the variability of the different houses design, energy performance, climate requirements, it was found that those values can vary of an order of two between the 10 and 90% percentiles’ values. It was found that the results are also sensitive to the enlargement of the system boundaries (e.g. inclusion of the other uses of energy such as building appliances) and the modification of the reference study period. Conclusions and recommendations : This study provided a first set of LCA guidance values describing a range of environmental impacts for new low-energy individual houses in France. Results were also reported for different design parameters, system boundaries and reference study period. The outcomes of this study can now serve as a basis to guide and support new LCA-based labelling systems developed by public authorities and labelling schemes (e.g. the HQE Association).

Influence of construction material uncertainties on residential building LCA reliability
Scientific paper ArODES

Endrit Hoxha, Guillaume Habert, Sébastien Lasvaux, Jacques Chevalier, Robert Le Roy

Journal of Cleaner Production,  2017, vol. 144, pp. 33-47

Link to the publication

Summary:

Life cycle assessment (LCA) is widely used to evaluate the environmental impacts of buildings, but due to uncertainties, the final results can be unreliable. To increase the reliability of LCA results, this study identifies the building materials that have the largest relative contribution to buildings' impacts and uncertainties. To do so, the impacts of 15 single-family houses and 15 multi-family building projects situated in France are evaluated. Only the uncertainties related to input parameters for building materials are considered (service life, characterization factors and quantity). The results obtained in this study show that LCA will still be able to distinguish significantly between two projects if their difference is higher than approximately 20%. Furthermore, the impacts of the buildings' exploitation phase do not show any correlations with the impacts related to the construction materials. The exploitation phase dominates the non-renewable energy consumption while waste impacts are most influenced by building materials. The contribution to global warming potential is shared between both phases. Finally, reinforced concrete was identified as the largest contributor to the environmental impact of both building types. In contrast, insulation materials and non-structural wood were the largest contributors to the uncertainties of the final results for single-family houses and multi-family buildings, respectively.

Product-specific Life Cycle Assessment of ready mix concrete :
Scientific paper ArODES
comparison between a recycled and an ordinary concrete

Annelore Kleijer, Sébastien Lasvaux, Stéphane Citherlet, Marco Viviani

Resources, Conservation and Recycling,  2017, 122, pp. 210-218

Link to the publication

Summary:

Recycled concrete is one of the most efficient answers to the shortage of natural aggregate in highly populated and protected regions, such as Switzerland. Although the technology has evolved and today a number of certified recycled concretes are available in the ready mix concrete market,there are still many barriers to its use for structural purposes. These are caused by early tests that, analyzing non-optimized or non-commercial products, reached the conclusion that the performances of recycled concrete would not match the ones of ordinary concrete. Furthermore, early studies on the environmental impact of recycled concrete seemed to confirm an identical environmental impact for recycled and ordinary concrete (Viviani 2011 ; Viviani 2014). In this paper, is presented a thorough Life Cycle Assessment (LCA) for a commercialized recycled concrete and a commercialized ordinary concrete of the same strength class, both certified, both deeply characterized, showing virtually identical physical and rheological properties and sold at the same price (recycled concrete price being slightly lower than the ordinary). This LCA study shows that recycled concrete is only slightly better than ordinary concrete in terms of greenhouse gases emissions. This difference is yet not enough significant (1%) as well as for the cumulative energy demand (4%). In opposite, it performs better with around 12% less environmental impacts according to the Swiss Ecological Scarcity 2006 Method. So, current actions taken to promote their use are fully in the direction of a more sustainable construction industry if the transportation distance to the construction site is minimized and below e.g., 25 km as recommended in the Swiss Minergie ECO label.

2016

Correlations in life cycle impact assessment methods (LCIA) and indicators for construction materials :
Scientific paper ArODES
what matters?

Sébastien Lasvaux, Fanny Achim, Philippe Garat, Bruno Peuportier, Jacques Chevalier, Guillaume Habert

Ecological Indicators,  2016, vol. 67, pp. 174-182

Link to the publication

Summary:

Different Life Cycle Impact Assessment (LCIA) methods have been developed over the past twenty years. While the use of a single score indicator may, on the one hand, ease the decision making it may also induce a loss of information. On the other hand, the use of a large set of environmental indicators may increase the difficulty of decision making due to the high number of parameters. In this paper, a statistical methodology is used to identify a simplified set of environmental indicators. This methodology applies Principal Component Analysis (PCA) to five LCIA methods (CML’01, Eco-indicator99, IMPACT 2002+, ecological scarcity, EPD) using a building products database. For each method, the results show that only 4–6 dimensions are sufficient to explain at least 90–95% of the variance for each set of indicators. They refer to the following environmental themes: fossil-fuel consumption, ecotoxicity, ionising radiation, land use and mineral resources. The use of a selected set of five LCI flows is found to be as relevant as current LCIA methods from a statistical point of view. Furthermore, PCA applied to a building LCA case study shows similar trends as for the database results. Further studies are now needed to confirm these findings for going towards simplified structural relationships among LCIA indicators for building materials.

2015

Comparison of generic and product-specific life cycle assessment databases :
Scientific paper ArODES
application to construction materials used in building LCA studies

Sébastien Lasvaux, Guillaume Habert, Bruno Peuportier, Jacques Chevalier

The International Journal of Life Cycle Assessment,  2015, vol. 20, pp. 1473-1490

Link to the publication

Summary:

Purpose : The Life Cycle Assessment (LCA) has been applied in the construction sector since the 1990s and is now more and more embedded in European public policies, e.g., for Environmental Product Declaration regulation or for building labeling schemes. As far as the authors know, these initiatives mainly rely on background impact data of building products provided by different databases’ providers. The new product-specific and company-specific EPD data allow having more than one data for describing a building material. But are these new databases really displaying similar LCA results compared to generic databases? Does it depend on which impact category (e.g., global warming, acidification, toxicity) is considered? Methods : To answer these research questions, this paper assesses numerical and methodological differences of two existing LCA databases for building LCAs: the ecoinvent generic database and one Environmental Product Declaration (EPD) database developed in France. After reviewing the main assumptions of these databases, numerical values of environmental impact are compared for 28 building materials using Life Cycle Impact Assessment (LCIA) indicators of the EN 15804 standard calculated based on cradle-to-gate ecoinvent and EPD Life Cycle Inventories (LCI). Results and discussion : Global results at the database level indicate deviations of different magnitudes depending on the LCIA indicators and the building materials. While indicators correlated to fossil fuel consumption, such as the ADP, the GWP, and the primary energy demand, exhibit a small deviation (approximately 25 %), other indicators, such as the photochemical ozone formation (POCP), radioactive waste, and ADP elements, are found to be more variable between EPD and generic data (sometimes by more than 100 %). Three indicators are found to be systematically different between EPD and generic data (i.e., the EPD value being either higher or lower for all materials). Similarly, five building materials show systematic differences for all LCIA indicators. Specific deviations for one indicator and one material are also reported. The application of the two databases on three building LCA case studies (brick, reinforced concrete, and timber frame structures) identifies deviations due to the most influential materials. Conclusions : Current generic and EPD databases can present very different values at the database scale which depend on the type of environmental indicator. For building LCA results, the situation is different as generally speaking a limited number of materials controlled the impacts. Finally, recommendations are presented for each environmental indicator to improve the consistency of the building assessment from generic to product- and country-specific information.

Methodological challenges and developments in LCA of low energy buildings :
Scientific paper ArODES
application to biogenic carbon and global warming assessment

Marine Fouquet, Annie Levasseur, Manuele Margni, Alexandra Lebert, Sébastien Lasvaux, Bernard Souyri, Catherine Buhé, Monika Woloszyn

Building and Environment,  2015, vol. 90, pp. 51-59

Link to the publication

Summary:

In Europe, low energy buildings become common for new constructions and life cycle assessment (LCA) is increasingly used to assess their environmental performance. The overall objective of this study is to investigate known challenges related to buildings LCA such as biogenic carbon accounting and dynamic and prospective aspects, and to discuss how they affect LCA results for low energy buildings and what developments are still needed. Three single family houses built respectively with timber frame, concrete blocks cavity wall, and cast concrete are used as a case study, focusing on the global warming impact category. When biogenic carbon is addressed, the timber house is the less impacting choice, whether it is landfilled or burned at the end-of-life. The cavity wall house is the second most favourable option, and the cast concrete house is the worst one. In the case of landfilling for the timber house, the biogenic carbon balance is not neutral and worth to be considered. When a dynamic approach and specific prospective scenarios are considered, the ranking between houses stays the same, but the gaps between options vary e.g. the gap between the landfilled timber house and the cast concrete house vary from 40 % to 60 % when optimistic changes in the electricity mix are considered. Dynamic LCA allows for a more consistent analysis of emissions flows and global warming impacts over time. Prospective LCA could provide more relevant LCA results but increases uncertainty and could be used as sensitivity analysis for long life span buildings.

Environmental product declarations entering the building sector :
Scientific paper ArODES
critical reflections based on 5 to 10 years experience in different European countries

Alexander Passer, Sébastien Lasvaux, Karen Allacker, Dieter De Lathauwer, Carolin Spirinckx, Bastian Wittstock, Daniel Kellenberger, Florian Gschösser, Johannes Wall, Holger Wallbaum

The International Journal of Life Cycle Assessment,  2015, vol. 20, pp. 1199-1212

Link to the publication

Summary:

Growing awareness of the environmental performance of construction products and buildings brings about the need for a suitable method to assess their environmental performance. Life cycle assessment (LCA) has become a widely recognised and accepted method to assess the burdens and impacts throughout the life cycle. This LCA-based information may be in the form of environmental product declarations (EPD) or product environmental footprints (PEF), based on reliable and verifiable information. All of these use LCA to quantify and report several environmental impact categories and may also provide additional information. To better understand on the one hand existing EPD programmes (EN 15804) for each country and on the other the recent developments in terms of EU reference document (e.g. PEF), the authors decided to write this review paper based on the outcomes of the EPD workshop that was held prior to SB13 Graz conference. This paper presents the state of the art in LCA and an overview of the EPD programmes in five European countries (Austria, Belgium, France, Germany, Switzerland) based on the workshop in the first part and a comprehensive description and comparison of the PEF method and EN 15804 in the second part. In the last part, a general conclusion will wrap up the findings and results will provide a further outlook on future activities. The high number of EPD programmes underlines the fact that there is obviously a demand for assessments of the environmental performance of construction materials. In the comparison between and experiences of the different countries, it can be seen that more similarities than differences exist. A comparison between PEF and EPD shows differences, e.g. LCIA impact categories and recycling methodology. Independent of raising awareness of the construction material environmental performance, the existence of so many environmental claims calls for clarification and harmonisation. Additionally, construction materials being assessed in the voluntary approaches have to follow the harmonised approach following the principles of the European Construction Products Regulation (regulated) not to foster barriers of trade. The authors therefore highly appreciate the most recent activities of the sustainability of construction works (CEN/TC 350 committee http://portailgroupe.afnor.fr/public_espacenormalisation/CENTC350/index.html) currently working on these issues at the EU level. Finally, the LCA community is further encouraged to increase the background life cycle inventory data and life cycle inventory modelling as well as the meaningfulness of certain environmental impact categories, such as toxicity, land use, biodiversity and resource usage.

NativeLCA - a systematic approach for the selection of environmental datasets as generic data :
Scientific paper ArODES
application to construction products in a national context

José Dinis Silvestre, Sébastien Lasvaux, Julie Hodková, Jorge de Brito, Manuel Duarte Pinheiro

The International Journal of Life Cycle Assessment,  2015, vol. 20, pp. 731-750

Link to the publication

Summary:

The aim of this paper is to propose guidelines for the selection of an accurate life cycle assessment (LCA) dataset of building products to be used as generic data for a national context. The guidelines are structured within a methodology, called NativeLCA. First, a review of available datasets for construction products is presented such as generic LCA and Environmental Product Declaration (EPD) databases for both national (e.g. France, Germany, Spain etc.) and European context. Secondly, a method is proposed to choose appropriate generic datasets by means of a hybrid methodology. A meta-analysis is conducted in the first step on the sample of collected datasets from the literature. When relevant, product-specific data (EPD of the different producers) are averaged to represent an average data or existing generic data are adapted to be more suitable for the context. Then, a data quality assessment enables to rank the different datasets according to the goal and scope of the study. This study provides consistent guidelines that can be used by building LCA practitioners to select relevant datasets depending on their goal and scope. A full case study for stone wool boards illustrates and demonstrates the applicability and usefulness of the proposed methodology, namely in the selection of a coherent dataset as generic data for a national context. This work highlights the issues in terms of choice and adaptation of existing data for a national context. Industry data cannot be adapted due to confidentiality issues unlike unit process generic data. The use of data quality indicators then helps to select the relevant generic data for each context according to user needs. While further efforts are needed to develop regional and sector-specific LCA databases adapted for each national context, the proposed guidelines showed that the current use or adaptation of existing data, if consistently done, can lead practitioners to increase the reliability of building LCA studies according to their goal and scope definition.

2014

Influence of simplification of life cycle inventories on the accuracy of impact assessment: application to construction products
Scientific paper ArODES

Sébastien Lasvaux, Nicoleta Schiopu, Guillaume Habert, J. Chevalier, Bruno Peuportier

Journal of Cleaner Production,  2014, vol. 79, pp. 142-151

Link to the publication

Summary:

The simplification of life cycle inventories (LCIs) by reducing the number of elementary flows is a major issue regarding their use in sector-specific applications. It can ease the understanding of complete LCIs and focus on the most relevant elementary flows. Current LCIs that have been created for Environmental Product Declarations (EPDs) differ from databases provided by academics, in which more than a thousand flows are considered, as they contain a reduced list of substances. In this paper, we examine the consequences of these simplified LCIs on the accuracy of the life cycle impact assessment (LCIA) step. We consider the specific case of an LCI database for building products that was developed in France. Three environmental midpoint and endpoint indicators are analysed: the global warming potential (GWP), the photochemical ozone formation potential (POCP), and the disability-adjusted life years (DALY). The results for 110 building materials indicate that a simplification is not always relevant, as large uncertainties were detected in the final results, especially for the environmental indicators describing the photochemical ozone creation and the damage to human health that require a larger number of LCI flows. In the case of the GWP indicator, the simplification is relevant for approximately 95% of the building materials. The analysis of the key elementary flows for each indicator enables the identification of missing elementary flows in the simplified LCI. Perspectives and recommendations are provided to improve the level of details of simplified LCIs according to the impact assessment methods.

Achieving consistency in life cycle assessment practice within the European construction sector: the role of the EeBGuide InfoHub
Scientific paper ArODES

Sébastien Lasvaux, Johannes Gantner, Bastian Wittstock, Manuel Bazzana, Nicoleta Schiopu, Tom Saunders, Cristina Gazulla, Jo Ann Mundy, Christer Sjöström, Pere Fullana-i-Palmer, Tim Barrow-Williams, Anna Braune, Jane Anderson, Katrin Lenz, Zsoka Takacs, Julien Hans, Jacques Chevalier

The International Journal of Life Cycle Assessment,  2014, vol. 19, pp. 1783-1793

Link to the publication

Summary:

The objective of the paper is to discuss the role of a new guidance document for life cycle assessment (LCA) in the construction sector available as an online InfoHub. This InfoHub derives from the EeBGuide European project that aimed at developing a guidance document for energy-efficient building LCA studies. The InfoHub is built on reference documents such as the ISO 14040-44 standards, the EN 15804 and EN 15978 standards as well as the ILCD Handbook. The guidance document was filled with expertise and knowledge of several experts. The focus was put on providing scientifically sound, yet practical guidance. The EeBGuide InfoHub is an online guidance document, setting rules for conducting LCA studies and giving instructions on how to do this. The document has a section on buildings—new and existing—and a section on construction products. It is structured according to the life cycle stages of the European standards EN 15804 and EN 15978, covering all aspects of LCA studies by applying provisions from these standards and the ILCD handbook, wherever applicable. The guidance is presented for different scopes of studies by means of three study types. For the same system boundaries, default values are proposed in early or quick assessment (screening and simplified LCA) while detailed calculation rules correspond to a complete LCA. Such approach is intended to better match the user needs in the building sector. This paper can be viewed as a contribution to the ongoing efforts to improve the consistency and harmonisation in LCA studies for building products and buildings. Further contributions are now needed to improve building LCA guidance and to strengthen links between research, standardisation and implementation of LCA in the construction practice.

Linking research activities and their implementation in practice in the construction sector :
Scientific paper ArODES
the LCA Construction 2012 experience

Sébastien Lasvaux, Anne Ventura, Guillaume Habert, Chantal De la Roche, Kristel Hermel, Adélaïde Ferraille, Yannick Tardivel, Christian Tessier

The International Journal of Life Cycle Assessment,  2014, vol. 19, pp. 463-470

Link to the publication

2013

Adaptation of environmental data to national and sectorial context :
Scientific paper ArODES
application for reinforcing steel sold on the French market

Fernanda Gomes, Raphaël Brière, Adélaïde Feraille, Guillaume Habert, Sébastien Lasvaux, Christian Tessier

The International Journal of Life Cycle Assessment,  2013, vol. 18, pp. 926-938

Link to the publication

Summary:

Environmental data for steel products are generally proposed at a continental or a global scale. The question we are tackling here is: does the fact that steel as a global market necessarily reduces the need for national data? In this study, the environmental impact of reinforcing steel sold in France is evaluated. To do so, a specific environmental inventory is adapted from Ecoinvent database. CML method is used for impact calculation and both methods “recycled content” as well as “end of life recycling approach” are tested. This study shows that there is a specificity of reinforcing steel products sold in France compared to European value. It is due to the fact that reinforcing steel is mainly made with recycled steel as the market growth for construction product in France is limited allowing a very high recycled content. This result is not sensitive neither to the allocation method used for recycling (cut-off approach or system expansion) nor to transport distance and electricity country mix used. The result of this study can be used with confidence in every construction site work located on the French territory. Furthermore, the present study advocates for an adaptation of global database to local context defined by a specific industrial sector and a geographic region even for product such as steel that may be considered as a first approximation as a global product.

2008

Predicting operational energy consumption profiles :
Scientific paper ArODES
findings from detailed surveys and modelling in a UK educational building compared to measured consumption

I. Knight, S. Stravoravdis, Sébastien Lasvaux

International Journal of Ventilation,  2008, vol. 7, no. 1, pp. 49-57

Link to the publication

Summary:

This paper presents the preliminary findings from the first stage of a physical survey and modelling case study conducted to obtain modelled and actual energy consumption profiles for a UK multi-storey mixed use educational building (the Bute building at the University of Wales, Cardiff). The purpose of the study is to provide an insight into how accurately current models and software can predict the actual energy consumption in such a building, with a view to informing the development of operational and asset ratings for buildings in the EU as part of the Energy Performance in Buildings Directive (EPBD) Article 7 requirements. The models used in this study were the software tool ECOTECT and the SBEM (Simplified Building Energy Methodology) version of the UK’s national calculation methodology. The study also briefly discusses the potential problems inherent in the use of modelling techniques for assessing the energy performance of buildings. The data obtained through this study enabled predicted energy consumption profiles for both heating/cooling and electrical energy use to be obtained, as well as a UK SBEM asset-type compliance rating. The predicted profiles and compliance rating were then compared to the monitored actual energy consumption profiles obtained over the same period. It was seen that the various modelling approaches gave a reasonable prediction of the gas consumption and a reasonable estimate of the electrical consumption using the SBEM. However, overall it was felt that further case studies would need to be tested to have any confidence in these findings. The relative agreement between the SBEM results in this case study and the measured consumption supports the view that for prediction of electrical consumption then statistically derived numbers, such as benchmarks, are likely to enable reasonably confident predictions of energy use by generic activity type.

2023

The "EcoDynElec" electricity model for buildings LCA: characteristics and effects?
Conference

Lasvaux Sébastien

DF 85 – Electricity in buildings LCA: State of the art, challenges, and ways ahead, 09.11.2023 - 09.11.2023, Zürich, Switzerland

Link to the conference

Summary:

With buildings, electricity consumption in construction, product manufacture and in the use phase is an important contributor to their environmental impacts. The forum will address electricity mix modelling issues in LCAs of buildings.

Several different models to represent the electricity consumed during the use phase of buildings are app¬lied in European countries: (1) the current national electricity consumer mix according to national statistics; (2) the electricity mix of the supplier, based on guarantees of origin (GO), (3) a (quasi dynamic) future electricity mix based on a national official energy scenario, (4) an individual electricity mix which covers the use profile of the building under assessment.

Companies in the supply chain of construction products purchase «green» electricity products to lower the environmental footprint of their products. These green electricity products are often based on GO or similar certification schemes. Physical production of electricity and electricity quality (GO) are then traded independently on different markets. This unique feature is a challenge for process based LCA.

The forum will discuss the following questions:

• What is the current state of electricity mix modelling for construction products and buildings’ use phases?

• How do different modelling approaches influence the transition of the electricity sector of a country to renewables?

• Which modelling approach is offered by leading LCA databases?

Breakout groups will allow for in depth discussions and identifying areas of consensus.

Reuse practices in building construction :
Conference ArODES
proposition of a life cycle assessment methodology and application to a case study in Switzerland

Mija Frossard, Sébastien Lasvaux, Florence Petetin, L. Gross

Journal of Physics: Conference Series ; Proceedings of cisbat 2023, the built environment in transititon, Hybrid International Scientific Conference

Link to the conference

Summary:

This paper presents a life cycle assessment (LCA) methodology for evaluating the environmental impacts of reuse in building projects and apply it to a case study in Switzerland with 11% of reused components in its total mass. The results show that the life cycle GHG emissions on the construction domain that includes modules A1 to A4, B4, and C1-C4, are 487 kg CO2-eq./m2. In the other hand, the indirect effect of reuse lead to avoided GHG emissions of 76 kg CO2-eq./m2. At the level of a product's supply chain, the analysis demonstrates a significant reduction in the embodied impacts of the reused components compared to newly manufactured ones. The potential benefits from avoided manufacturing and waste management depend on the type of material that is reused.

Economic and environmental benefits of decentralized multi-energy systems for energy communities
Conference ArODES

Xavier Jobard, Massimiliano Capezzali, Neha Dimri, Alexis Duret, Marten Fesefeldt, Mija Frossard, Vincent Jacquot, Sébastien Lasvaux

Journal of Physics: Conference Series ; Proceedings of cisbat 2023, the built environment in transititon, Hybrid International Scientific Conference

Link to the conference

Summary:

In the context of growing interest in decentralised multi energy systems, this work aims at quantifying the benefit of optimized energy concepts for energy communities at the neighbourhood scale compared to individually optimized solution. To tackle this question a multi-objective optimization framework was developed and applied to a case study of 6 buildings consisting of 85% of residential dwellings and 15% to retail shop and food stores. Grouped buildings have decreased costs and greenhouse gases emissions (GHGE) respectively by 18% and 12% in the cost optimum compared to individual buildings. In the environmental optimum, costs have decreased by 11%, while GHGE remains in the same range. This decrease is at both optimum driven by electricity prices favourable to large consumers since exchanges on the electrical microgrid for this neighbourhood is very small. Optimal decrease of GHGE is obtained with greater use of HPs and smaller natural gas consumption. This work illustrates the interest of multi-objective approaches to identify optimal energy solutions for groups of buildings.

Life cycle assessment of the new solar thermal power plant SolarCAD II connected to a district heating network in Geneva, Switzerland
Conference ArODES

J. Solano, Mija Frossard, Sébastien Lasvaux, Alexis Duret

Journal of Physics: Conference Series ; Proceedings of CISBAT 2023, the built environment in transititon, Hybrid International Scientific Conference

Link to the conference

Summary:

This paper presents a life cycle assessment (LCA) of the solar heat injected in a District Heating Network (DHN) by a new solar thermal power plant in Geneva. An environmental Life Cycle Assessment (LCA) is conducted according to ISO 14040, ISO 14044 and SN EN 15804+A2:2019. The scope of the study includes the complete life cycle of the solar power plant heat generation system. The baseline GHG emissions results show that the solar heat injected is responsible of about 15 to 18 gCO2-eq per kWh depending on whether we account for the environmental impacts of the steel gratings or not. This value is mostly determined by the manufacturing and use stages. Different sensitivity analyses are then performed in order to test the robustness of the main influential parameters (e.g., lifetime, efficiency, electricity mix) and better quantify the variability of the GHG emissions. Finally, this LCA study of a solar thermal plant connected to a Swiss DHN provides a first value of the solar heat in comparison with other heat production routes for DHN already provided in LCA databases such as the Swiss KBOB 2009/1:2022 platform for LCA in the construction sector.

2021

Bio-based materials as a robust and optimal solution for building renovation
Conference ArODES

Alina Galimshina, Maliki Moustapha, Alexander Hollberg, Sébastien Lasvaux, Bruno Sudret, Guillaume Habert

Proceedings of CEES 2020, International Conference "Construction, Energy, Environment & Sustainability"

Link to the conference

Summary:

Building energy renovation is urgent in order to lower green house gas (GHG) emissions and achieve carbon neutrality by 2050. Building energy renovation can be achieved by more efficient thermal insulation and replacing the fossil heating system in a building. Currently, conventional building insulation materials dominate the market. However, to drastically reduce GHG emissions, bio-based materials are a valuable asset. These can be applied not only to reduce the operational energy but also to temporarily store carbon in the building stock. To evaluate the environmental and cost performance of such insulation, life cycle cost analysis (LCCA) and environmental life cycle assessment (LCA) can be used. However, as buildings are long lasting systems, many parameters in these analyses are uncertain. Such parameters include the future climate, future inflation rates, point in time when materials are replaced, future energy policies, and so on. In this paper, we apply bio-based insulation materials for building renovation and define the optimal solution for building energy-related renovation using a novel methodology, which combines non-dominated sorting genetic algorithm (NSGA-II) with surrogate modeling. We use materials such as straw, hemp, and wood fibre along with conventional materials such as EPS. At the same time, we account for the uncertainties associated with these materials’ production and replacement as well as those associated with the future building operation. In this analysis, we also include the carbon storage calculation. The results show that bio-based materials provide a robust solution for building renovation and have high potential to store carbon in building components in comparison with conventional insulation materials. The results also show that to achieve the highest GHG emissions reduction, building energy-efficient measures should be combined with the replacement of the existing fossil heating system. The approach presented here allows the identification of the robust and optimal building renovation solution performed with bio-based materials and the comparison of such renovation with conventional materials.

Dynamic LCA of a single-family house, equipped with a micro-cogeneration unit, using a variable share of biomethane
Conference ArODES

Pierryves Padey, Marten Fesefeldt, Kyriaki Goulouti, Sébastien Lasvaux, Massimiliano Capezzali

Journal of Physics: Conference Series ; Proceedings of CISBAT 2021 Carbon-neutral cities - energy efficiency and renewables in the digital era

Link to the conference

Summary:

The current study presents the CO2-eq emissions of the operational energy use of a single-family house, equipped with a micro-cogeneration unit. A back-up boiler and electricity from the grid cover the remaining energy demand, not covered by the micro-CHP. Two different technologies are evaluated, i.e. ICE and fuel cell systems, operating with a variable share of biomethane, while two different substrates were considered for the biomethane generation. A dynamic LCA was applied for the electricity mix, coming from the grid, using different time steps. The results show that producing biomethane from biowaste compared to conventional natural gas is beneficial, in terms of CO2-eq emissions, independently of the micro-CHP technology, while the total CO2-eq emissions of the fuel cell technology are higher than those of the ICE, independently of the substrate and the biomethane share.

2020

Implications of using systematic decomposition structures to organize building LCA information :
Conference ArODES
a comparative analysis of national standards and guidelines- IEA EBC ANNEX 72

B. Soust-Verdaguer, A. Garcia Martinez, C. Llastas, J. C. Gomez de Cozar, K. Allacker, D. Trigaux, E. Alsema, B. Berg, D. Dowdell, W. Debacker, R. Frischknecht, L. Ramseier, J. Veselka, M. Volf, P. Hajek, A. Lupisek, Z. Malik, Guillaume Habert, A. Hollberg, Sébastien Lasvaux, B. Peuportier, F. Pomponi, L. Wastiel, V. Gomes, O. Zara, M. Gomes, A. Gusson Baiocchi, L. Pulgrossi, C. Ouellet-Plamondon, A. Moncaster, R. di Bari, R. Horn, K. Lenz, M. Balouktsi, T. Lützkendorf, M. Röck, E. Hoxha, A. Passer

IOP Conference Series: Earth and Environmental Science ; Proceeding sof BEYOND 2020, World Sustainable Built Environtment Online Conference, 2-4 November 2020, Göteborg, Sweden

Link to the conference

Summary:

Introduction: The application of the Life Cycle Assessment (LCA) technique to a building requires the collection and organization of a large amount of data over its life cycle. The systematic decomposition method can be used to classify building components, elements and materials, overcome specific difficulties that are encountered when attempting to complete the life cycle inventory and increase the reliability and transparency of results. In this paper, which was developed in the context of the research project IEA EBC Annex 72, we demonstrate the implications of taking such approach and describe the results of a comparison among different national standards/guidelines that are used to conduct LCA for building decomposition. Methods: We initially identified the main characteristics of the standards/guidelines used by Annex participant countries. The "be2226" reference office building was used as a reference to apply the different national standards/guidelines related to building decomposition. It served as a basis of comparison, allowing us to identify the implications of using different systems/standards in the LCA practice, in terms of how these differences affect the LCI structures, LCA databases and the methods used to communicate results. We also analyzed the implications of integrating these standards/guidelines into Building Information Modelling (BIM) to support LCA. Results: Twelve national classification systems/standards/guidelines for the building decomposition were compared. Differences were identified among the levels of decomposition and grouping principles, as well as the consequences of these differences that were related to the LCI organization. In addition, differences were observed among the LCA databases and the structures of the results. Conclusions: The findings of this study summarize and provide an overview of the most relevant aspects of using a standardized building decomposition structure to conduct LCA. Recommendations are formulated on the basis of these findings.

Robust and resilient renovation solutions in different climate change scenarios
Conference ArODES

Alina Galimshina, Maliki Moustapha, Alexander Hollberg, Pierryves Padey, Sébastien Lasvaux, Bruno Sudret, Guillaume Habert

IOP Conference Series: Earth and Environmental Science ; BEYOND 2020 – World Sustainable Built Environment conference, 2-4 November 2020, Göteborg, Sweden

Link to the conference

Summary:

Building renovation is currently urgent in order to decrease the energy consumption of a building stock. In order to achieve robust renovation scenarios, uncertainty quantification is needed. Climate change scenarios are important factors and need to be included in the analysis. In this paper, three climate change scenarios are applied probabilistically for a renovation scenario using dimensionality reduction techniques and further uncertainty propagation. The results show that RCP2.6 provides more robust results and saves on average 2. 105 CHF and 2. 105kgCO2eq. in a building life cycle comparing to RCP 8.5. The analysis under climate change is also compared to the probabilistic calculations under current climate and the results show the underestimation of both costs and environmental impacts when climate change is not included. It can also be clearly seen that even under the best case of RCP 2.6, building renovation is urgently needed to decrease the environmental impacts and costs.

Dynamic Life Cycle Assessment of the building electricity demand :
Conference ArODES
a case study

Pierryves Padey, Kyriaki Goulouti, Didier Beloin Saint-Pierre, Sébastien Lasvaux, Massimiliano Capezzali, Vasco Medici, Jalomi Maayan Tardif, Stéphane Citherlet

Proceedings of 21. Status-Seminar "Erneuern! Sanierungsstrategien für den Gebäudepark", 3-4 September 2020, Aarau, Switzerland

Link to the conference

Summary:

The environmental footprint of the Swiss consumed electricity is not constant over the year. Indeed, the share of the energy production means varies throughout the days, weeks and months, as a function of the electricity demand, resource availability (hydro, solar) and the power plant availability (maintenance). Switzerland also balances its electricity grid with imports from neighboring countries. All these possible fluctuations imply a variable environmental footprint of the Swiss consumed electricity, which affect the environmental impact of the building electricity demand. So far, in Switzerland, the environmental accounting of the building energy demand considers yearly average impacts for the consumed electricity. The EcoDynBat project has developed a framework to collect and merge all the necessary data to conduct a Dynamic Life Cycle Assessment (DLCA) of the environmental impact for the Swiss building consumed electricity under different time steps. The resulting database and methodology has been applied to different profiles of building electricity demand, including buildings with heat pump and/or decentralized electricity production systems. The study evaluates the influence of different time step resolutions on the environmental impacts of the electricity demand in Swiss buildings. Results for the climate change impact show a variability going from 36 to 580 g of CO2 eq/kWh for the consumed electricity when using an hourly resolution, during a one year period. This variability causes an increase in the impacts of up to 24% for space heating, when compared to the annual average impacts. Other electricity loads that do not have a seasonal profile are less affected by the time resolution. Nevertheless, observed trends suggest that an hourly resolution will be relevant to evaluate the potential environmental impacts of smart buildings.

Analysis of lifetimes of building elements in the literature and in renovation practices and sensitivity analysis on building LCA & LCC
Conference ArODES
a case study

Sébastien Lasvaux, Kyriaki Goulouti, Didier Favre, Morgane Giorgi, Pierryves Padey, Benjamin Volland, Medhi Farsi, Guillaume Habert, Alina Galimshina

Proceedings of 21. Status-Seminar "Erneuern! Sanierungsstrategien für den Gebäudepark", 3-4 September 2020, Aarau, Switzerland

Link to the conference

Summary:

In this study, the service lives of the building elements, an important parameter in renovations and LCA/LCC calculations, are analyzed, based on a comprehensive literature review and a survey of Swiss households. The literature review showed that there is no consensus about the service lives, among the different countries, while the results of the survey on the renovation timing of the building elements, showed on average an agreement between the element’s effective lifetime and the average from the literature data. In addition, based on the literature data, lognormal distributions were defined for the service life of the building elements and then the probabilistic LCA & LCC were calculated. The results showed that the uncertainty of 6 building elements’ service lives can significantly influence the reliability of the results. For the practitioners, the study confirms that the current practice of using service life data of the SIA 2032 technical books, for building LCA and LCC, constitutes a relative good estimation of the most probable value of the probabilistic LCA.

Uncertainty and sensitivity analyses for evaluating the building element's replacement in building LCA
Conference ArODES

Kyriaki Goulouti, Pierryves Padey, Alina Galimshina, Guillaume Habert, Sébastien Lasvaux

Proceedings of the XV International Conference on Durability of Building Materials and Components DBMC 2020, 30 June-3 July 2020, Barcelona, Spain

Link to the conference

Summary:

This paper presents a systematic way to consider the uncertainties of the building elements’ service lives within a stochastic framework, by defining the corresponding probability density functions, based on a service life database. This methodology is appropriate for screening and detailed building LCA, since the service life database offers the possibility to define the probability density functions of the service lives, in different level of details.

Development of a service life database of building elements based on an international data collection
Conference ArODES

Kyriaki Goulouti, Morgane Giorgi, Didier Favre, Sébastien Lasvaux

Proceedings of the XV International Conference on Durability of Building Materials and Components DBMC 2020, 30 June-3 July 2020, Barcelona, Spain

Link to the conference

Summary:

This paper presents a new service life database (DUREE database) for building elements, based on international service life data. The database includes 7‘000 service life data, for more than 2‘000 building elements. In addition, the fitting of the data to a lognormal distribution is presented. The study contributes to the increasing demand of probabilistic building LCA and LCC and provides the possibility to define statistical distributions, with a systematic way, for a large number of building elements and different levels of details (LOD), appropriate for BIM-based assessments.

2019

Energy saving potentials in historic buildings’ renovations :
Conference ArODES
to which extent is the heating demand limit value (SIA 380/1) reachable and at which costs?

Didier Favre, Kyriaki Goulouti, Pierryves Padey, Sébastien Lasvaux

Journal of Physics: Conference Series - Proceedings of CISBAT 2019 – International Scientific Conference, 4-6 September 2019, Lausanne, Switzerland

Link to the conference

Summary:

The renovation of historic buildings is essential to meet the Swiss objectives for energy consumption in 2050. These buildings offer a great saving potential, however, the heritage preservation has to be considered in the renovation scenarios. While essential for the historic conservation, this consideration restricts the renovation possibilities to achieve the heating demand requirements according to the SIA 380/1 standard. This study introduces a framework for identifying the suitable historic buildings’ renovation schemes considering life cycle costs, energy and life cycle environmental impacts. With a case study, the feasibility of achieving the energy performance SIA 380/1 standard is then discussed.

Hygrothermal assessment of historic buildings' external walls :
Conference ArODES
preliminary findings from the RIBuild project for Switzerland

Morgane Giorgi, Didier Favre, Kyriaki Goulouti, Sébastien Lasvaux

Journal of Physics: Conference Series - Proceedings of CISBAT 2019 – International Scientific Conference, 4-6 September 2019, Lausanne, Switzerland

Link to the conference

Summary:

To meet the national regulation on building energy needs while preserving the architectural heritage, the renovation of protected historic buildings implies to insulate internally their facades. However, it is a technically risky solution. This work is part of the European project RIBuild that develops guidelines to ensure moisture-safe solutions. For that purpose, historical buildings were monitored to confront the current state-of-the-art of hygrothermal simulations with in-situ measurements. To enforce these calculations, stones used in Swiss traditional construction were characterised, and materials' modelling were investigated. The results of the study will be integrated into a probabilistic web-tool.

Comparison of the environmental assessment of an identical office building with national methods
Conference ArODES

R. Frischknecht, H. Birgisdottir, C.-U. Chae, T. Lützkendorf, A. Passer, E. Alsema, M. Balouktsi, B. Berg, D. Dowdell, A. Garcia Martinez, G. Habert, A. Hollberg, H. König, Sébastien Lasvaux, C. Llatas, F. Nygaard Rasmussen, B. Peuportier, L. Ramseier, M. Röck, B. Soust Verdaguer, Z. Szalay, R.A. Bohne, L. Bragança, M. Cellura, C. K. Chau, M. Dixit, N. Francart, V. Gomes, L. Huang, S. Longo, A. Lupisek, J. Martel, R. Mateus, C. Ouellet-Plamondon, F. Pomponi, P. Ryklova, D. Trigaux, Y. Yang

IOP Conference Series: Earth and Environmental Science ; Proceedings of Sustainable Built Environment D-A-CH Conference 2019 (sbe19 Graz), 11–14 September 2019, Graz, Austria

Link to the conference

Summary:

The IEA EBC Annex 72 focuses on the assessment of the primary energy demand, greenhouse gas emissions and environmental impacts of buildings during production, construction, use (including repair and replacement) and end of life (dismantling), i.e. during the entire life cycle of buildings. In one of its activities, reference buildings (size, materialisation, operational energy demand, etc.) were defined on which the existing national assessment methods are applied using national (if available) databases and (national/regional) approaches. The "be2226" office building in Lustenau, Austria was selected as one of the reference buildings. TU Graz established a BIM model and quantified the amount of building elements as well as construction materials required and the operational energy demand. The building assessment was carried out using the same material and energy demand but applying the LCA approach used in the different countries represented by the participating Annex experts. The results of these assessments are compared in view of identifying major discrepancies. Preliminary findings show that the greenhouse gas emissions per kg of building material differ up to a factor of two and more. Major differences in the building assessments are observed in the transports to the construction site (imports) and the construction activities as well as in the greenhouse gas emissions of the operational energy demand (electricity). The experts document their practical difficulties and how they overcame them. The results of this activity are used to better target harmonisation efforts.

2018

Modèle probabiliste de la consommation énergétique d'un bâtiment pour l'étude de l'écart de performances
Conference ArODES

Pierryves Padey, Blaise Périsset, Sébastien Lasvaux, Stéphane Genoud, Joëlle Mastelic

Proceedings of 20. Status-Seminar "Forschen für den Bau im Kontext von Energie und Umwelt", Zurich, Switzerland, 6-7 September 2018

Link to the conference

Summary:

The UserGap project aims at assessing the « Energy Performance Gap” (EPG) between simulated and real consumption for low energy buildings. Indeed, in these building, the energy consumption is more and more sensitive to the user behaviour and the technical installation performances. The project’s objectives are 1) to compare the energy consumption between simulation and reality, 2) to characterize the performance gap and identify the users’ influence and 3) to test the implementation of energy saving measures with a “Living lab”. Thereby, a stochastic simulation model the energy consumption has been developed based on the SIA 380/1 norm. It has for output a distribution of the energy consumption as a function of uncertainty of the model’s input parameters (characterized with probability distribution function). In Ex-Post evaluation, the model is calibrated by replacing some uncertain parameters by in-situ measured values so as to approximate the real energy consumption. The parameters influencing the EPG (technics and users) can then be hierarchized/ranked using this simulation strategy. This approach can be used: - In conception: to identify the users’ influence on the energy demand by simulating monthly energy consumption with probability distribution for the “users’ parameters” - In use: to verify the observed energy consumption by adjusting the simulation and propose corrective actions via Living Lab.

2016

Optimum environnemental et financier des isolations pour les rénovations
Conference ArODES

Sébastien Lasvaux, Catherine Hildbrand, Didier Favre, Blaise Périsset, Jacques Bony, Stéphane Citherlet

Proceedings of 19. Status-Seminar « Forschen für den Bau im Kontext von Energie und Umwelt »

Link to the conference

Summary:

Cet article s’inscrit dans le projet ECO-Reno "Rénovation à faible impacts environnementaux dans le domaine de l’habitation" et présente une approche permettant de déterminer des couples optimaux isolant/système de chauffage permettant de minimiser les impacts environnementaux et les coûts combinés entre l’isolation et la consommation d’énergie nécessaire au chauffage d’un bâtiment. La particularité de ce travail réside dans la prise en compte des contraintes réelles liées à la pose d’isolation. L’analyse a été faite sur quatre éléments de construction associés à cinq systèmes de chauffage différents. Les résultats montrent que ces couples diffèrent selon l’indicateur évalué et que les EOI (épaisseur optimale d’isolation) financières sont généralement plus faibles que les EOI environnementales. De plus, les résultats obtenus avec cette méthode ont été comparés avec les épaisseurs d’isolants préconisés par les normes et les labels énergétiques actuels. Ce point a mis en évidence que le respect des normes engendre systématiquement un surcoût financier et environnemental sur la durée de vie du bâtiment alors que la pose d’épaisseurs satisfaisant le label Minergie-P® permet d’être proche des optimums financiers et environnementaux.

Étude détaillée d'une rénovation à haute performance énergétique d'un bâtiment multifamilial
Conference ArODES

Jacques Bony, Didier Favre, Sébastien Lasvaux, Blaise Périsset, Catherine Hildbrand, Sara Eicher, Stéphane Citherlet

Proceedings of 19. Status-Seminar « Forschen für den Bau im Kontext von Energie und Umwelt »

Link to the conference

Summary:

Cet article s’inscrit dans le projet ECO-Reno "Rénovation à faible impacts environnementaux dans le domaine de l’habitation" et présente une évaluation des impacts environnementaux et des coûts liés à la rénovation énergétique d’un bâtiment d'habitation de 59 appartements. L'analyse de cycle de vie montre des résultats très positifs quel que soit l'indicateur environnemental considéré (CEDNRE, GWP et UBP). La part des matériaux utilisés dans la rénovation reste faible en comparaison des économies d'énergie réalisées. Les aspects financiers ont mis en évidence la grande influence de l’évolution du prix de l'énergie sur le nombre d'années nécessaire pour le remboursement des investissements. Dans le cas de ce bâtiment, ce remboursement via les économies d’énergie parait difficile à l'échelle du temps des constructions actuelles. Cependant, une répercussion des coûts de rénovation a été effectuée sur les loyers et permet d'envisager l’exploitation financière de ce bâtiment sereinement.

Economic and environmental assessment of building renovation :
Conference ArODES
application to residential buildings heated with electricity in Switzerland

Blaise Périsset, Sébastien Lasvaux, Catherine Hildbrand, Didier Favre, Stéphane Citherlet

Proceedings of Sustainable Built Environment (SBE) regional conference ; Expanding Boundaries: Systems Thinking for the Built Environment, 15-17 June 2016, Zurich, Switzerland

Link to the conference

Summary:

Following the Fukushima accident in 2011, Switzerland decided to start turning off the electricity coming from nuclear power plants as a part of an ambitious “Energy Strategy 2050” including better energy savings and efficiency of buildings and the development of renewable energies. In this new framework, one of the measures concerns the replacement of direct electric heating systems. It has been discussed in some Swiss cantons and increases the pressures on building tenants that use direct electricity as energy carrier e.g., for heating. However, from an environmental and economic point of view it is not clear yet whether it is better to renovate the building envelope, the electric heating systems or a combination of both. As several alternatives exist during a building renovation, the objective of this paper is to conduct an integrated economic and environmental assessment of four representative scenarios using the Life Cycle Assessment and Life Cycle Cost methodologies based on Swiss standards and cost data collected from manufacturers. From an economic point of view, results showed that the renovation of the electric heating system by a heat pump, solution often promoted by Swiss cantons, enables to get similar costs compared to the existing building. This solution is more interesting than the building envelope renovation or the switch to another heating system for which a technical room needs to be created. From an environmental point of view, the building envelope renovation is fundamental to lower the impacts. The partial renovation of the building envelope while keeping the direct electric heating system gives equivalent results compared to the only replacement of the electric heating by an air-to-water heat pump. Finally, this study shows that it is not always possible to be below the indicative values of the SIA 2040 standard “Energy Efficiency Path” (intermediate goals of the 2000-Watt Society) for the “Construction” and “Operational” aspects for building renovation.

Selection of environmental datasets as generic data :
Conference ArODES
application to insulation materials within a national context

J. D. Silvestre, Sébastien Lasvaux, J. Hodkova, J. de Brito, M. D. Pinheiro

Proceedings of Sustainable Built Environment (SBE) regional conference ; Expanding Boundaries: Systems Thinking for the Built Environment, 15-17 June 2016, Zurich, Switzerland

Link to the conference

Summary:

Purpose: The aim of this paper is to present the application of the NativeLCA methodology to the selection of Life Cycle Assessment (LCA) datasets of insulation materials to be used as generic data within a national context. Method: NativeLCA is applied to the following products: stone wool (SW), polyurethane and insulation cork boards, expanded and extruded polystyrene, and lightweight expanded clay aggregates. Following the NativeLCA methodology, a review of available datasets for these insulation products is presented (i.e. generic LCA and Environmental Product Dec-laration databases). For each material (except SW), the aim was to verify the plausibility of LCA studies completed based on site-specific data, in order to use the latter as generic data within a national context. Results and discussion: The case studies presented in this paper demonstrate the applica-bility and usefulness of using NativeLCA in the selection of a coherent dataset as generic data within a national context. Moreover, the application of this methodology to six case studies showed its feasibility, benefits, and limitations, while allowing the identification of some potential improvements. Conclusion: NativeLCA relies on the selection of LCA data sets of construction products available in the European context to be used as generic for a national context. This is a straightforward approach, focused on the selection of a LCA data set to be directly used by LCA practitioners. The scope of NativeLCA was limited in this paper to insulation ma-terials, but this methodology can be applied to other building products.

Towards a reliable comparison between environmental and economic cost of swiss dwellings :
Conference ArODES
a model with building materials service life uncertainty

I.-F. Haefliger, V. John, Sébastien Lasvaux, E. Hoxha, A. Passer, Guillaume Habert

Proceedings of Sustainable Built Environment (SBE) regional conference ; Expanding Boundaries: Systems Thinking for the Built Environment, 15-17 June 2016, Zurich, Switzerland

Link to the conference

Summary:

Purpose: In this study, the authors develop a method for the estimation of uncertainties arising from the building material service-life in the context of building LCA and LCC. Method: Life Cycle Assessment and Life Cycle Costing analysis were conducted on four newly built Swiss dwellings. The related uncertainties arising for the variability of the building material service lives was evaluated with a Monte Carlo simulation. Findings: The outcome of the study shows that the greenhouse gas emissions or the cost uncertainties of the replacements represent between 6 and 16% of the total result of the buildings’ LCA or LCC. Furthermore, the uncertainties’ estimation of the replacements allows to compare more accurately the buildings’ environmental or economic performances. Conclusion: The study highlights the interest of taking into account uncertainty estimation for the replacement phase, especially in the context of more energy efficient buildings.

2015

Life cycle assessment of energy related building renovation :
Conference ArODES
methodology and case study

Sébastien Lasvaux, Didier Favre, Blaise Périsset, Jacques Bony, Catherine Hildbrand, Stéphane Citherlet

Energy Procedia ; Proceedings of the 6th International Building Physics Conference, IBPC 2015, 14-17 June 2015, Torino, Italy

Link to the conference

Summary:

The building sector contributes up to 40% of energy consumption and 30% of greenhouse gases emissions (GHG) worldwide [1]. One of the main driver to mitigate these energy and GHG emissions is the renovation of existing buildings. While the energy demand is reduced during an energy related renovation, investment costs and environmental impacts increase due to the materials and building integrated technical systems (BITS) replaced or added to improve its energy performance. To address these trade-offs, there is a need to consider a life cycle approach to avoid impacts’ transfer between the operational and embodied energy and impacts. In this paper, we present a pragmatic Life Cycle Assessment (LCA) methodology for energy related renovation measures of building developed in the framework of the IEA annex 56 “Cost effective energy and carbon emissions optimization in building renovation”. The approach is consistent with the existing building LCA's state-of-the-art but goes into a more applicable methodology by focusing only on the significant life cycle stages for energy related building renovation i.e. the production, transportation, replacement and end of life of new materials for the thermal envelope and building integrated technical systems (BITS) and the operational energy demand. In this paper, the methodology is applied on a Swiss multi-family residential building built in 1965 which was renovated in 2010. The LCA is presented using three indicators: the total and non-renewable cumulative energy demand (CED) and the global warming potential (GWP). Results show that embodied CED and GWP remain negligible in the renovated building compared to the energy savings. Further studies are needed to further apply this LCA methodology.

2007

Assessing the operational energy profiles of UK educational buildings :
Conference ArODES
findings from detailed surveys and modelling compared to measured consumption

Ian Knight, Spyridon Stravoravdis, Sébastien Lasvaux

Proceedings of 2nd PALENC Conference and 28th AIVC Conference on Building Low Energy Cooling and Advanced Ventilation Technologies in the 21st Century, 27-29 September 2007, Crete, Greece

Link to the conference

Summary:

This paper presents the preliminary findings from the first stage of a physical survey and modelling Case Study conducted to obtain Modelled and Actual Energy Consumption Profiles for a UK multi-storey mixed use educational building. The purpose of the study is to provide an insight into how accurately current models and software can predict the actual energy consumption in such a building, with a view to informing the development of Operational and Asset Ratings for Buildings in the EU as part of the EPBD Article 7 requirements. The study also briefly discusses the potential problems inherent in the use of modelling techniques for assessing the energy performance of buildings. The data obtained through this study allowed predicted energy usage profiles to be compiled from the level of individual items of equipment through to the whole building. These data were subsequently analysed using standard spreadsheet and building energy simulation software. The results of the analysis enabled predicted energy consumption profiles for both heating/cooling and electrical energy use to be obtained, as well as a UK iSBEM asset-type compliance rating. The predicted profiles and compliance rating were then compared to the monitored actual energy consumption profiles obtained over the same period. The main conclusions were that, despite the time needed to undertake the physical survey, the level of detail of this study and survey were insufficient to predict the energy consumptions of the building with confidence. It was seen that the various approaches gave a reasonable estimate of the gas consumption using ECOTECT, and a reasonable estimate of the electrical consumption using iSBEM. However, overall it was felt that the models were too inaccurate to be used with any confidence. This results of this Case Study also support the view that for prediction of electrical consumption then statistical measures, such as benchmarks, are likely to enable more confident predictions of energy use by generic activity type.

Achievements

Sans date

[depuis oct. 2024] Membre du groupe spécialisé (Fachgruppe) de la plate-forme de données d'écobilan dans le domaine de la construction KBOB/ecobau/IPB

 2025 ; Expertise en écobilan

Collaborateurs: Lasvaux Sébastien

Link to the achievement

Cette plate-forme cadre la mise à disposition de données d'écobilan pour le secteur de la construction sous la forme de la liste de données KBOB qui elle-même est reprise pour évaluer l'empreinte carbone des bâtiments dans les normes et règlementations en vigueur en Suisse

[depuis juin 2023] Co-editor Building & Construction section, ecoinvent database

 2025 ; Expertise en écobilan

Collaborateurs: Lasvaux Sébastien

Link to the achievement

Activités ponctuelles de review de jeux de données de la section Building & Construction de la base de données ecoinvent.

[depuis janvier 2016] Membre commission SIA 2032 "L’énergie grise - Établissement du bilan écologique pour la construction de bâtiments"

 2025 ; Expertise en écobilan

Collaborateurs: Lasvaux Sébastien

Link to the achievement

Société Suisse des Ingénieurs et Architectes (SIA)

[depuis sept. 2014] Habilitation programme de vérification INIES FDES de déclarations environnementales de produits de construction (France)

 2025 ; Expertise en écobilan

Collaborateurs: Lasvaux Sébastien

Link to the achievement

Expert habilité par le programme de vérification INIES FDES pour la revue/vérification de données d'écobilan sous la forme de fiche FDES de produits de construction utilisées dans la règlementation "carbone" des bâtiments RE2020 en France.

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