Économie verte | EPFL Graph Search

L'économie verte est l'activité économique . Ce modèle économique obéit aux règles, aux principes et aux critères du développement durable. Les autres modèles économiques peuvent parfois être qualifiés de gris ou noirs ; conduisant aux pollutions, au gaspillage et/ou à l'épuisement des ressources non renouvelables, et à la destruction de l'environnement, ou rouges dans le cas où l'on tire profit de la vente des armes par exemple. Avant tout l'économie verte est liée au respect de la nature et cherche à maintenir le capital naturel en équilibre (c'est-à-dire à ne pas consommer plus de ressource que ce que les écosystèmes, la Terre et le Soleil peuvent fournir, tout en maintenant les services écosystémiques équitablement disponibles pour tous et pour les générations futures). Au sein de l'économie verte, les éco-activités s'attachent donc directement à la restauration ou à la protection de l'environnement et la préservation des ressources naturelles et humaines, surtout quand elles s

Articulating natural resources and sustainable development goals through green economy indicators: A systematic analysis

Marta Giulia Baldi, Ian Gunderson, Albert Merino, Bruno Maria Camelo Oberle

Natural Resources are essential inputs for economic and social development. However, unsustainable resource use has led to environmental degradation and resource depletion, endangering the well-being of humanity and the environment. The 2030 Agenda for Sustainable Development and its 17 Sustainable Development Goals (SDGs) represent a plan of action to address these issues. The Green Economy (GE) concept is described by various institutions as a vehicle to move towards sustainable resource management. This paper demonstrates the linkages between SDGs and Natural Resources though the systematic analysis of 494 GE indicators, derived from 12 distinct frameworks focusing on GE or on Green Growth. This articulation provides insights to gain an improved understanding of the links between SDGs and Natural Resources and interpret their inherent complexity. GE indicators focus unevenly on SDG, although each SDG is related to at least one resource category. Two complementary typologies were applied to the Materials subcategory to highlight additional characteristics, leading to the proposal of an adaptable analytical framework for the assessment of sustainability issues and GE transitions.

ELSEVIER SCIENCE BV2018

Multi-Scale Study of High-Temperature Latent Heat Storage With Metallic Phase Change Materials

Nithin Mallya

Energy storage is a central issue in the green economy with half the global end energy usage being heat. Latent heat thermal energy storage (LHTES) provides an energy dense heat storage solution with a well-defined discharge temperature. Utilizing low-cost, high-temperature, high-conducting metal alloys as phase change materials (PCMs) enables high energy and power density LHTES systems. Detailed characterization, reliable design tools and guidelines for modelling and building such systems are missing. This thesis presents design-related and operation-oriented innovations for such systems at different scales: (a) application-scale experimental-numerical demonstration of a LHTES test-bed, (b) non-dimensional numerical study of low and high-conducting PCMs at storage-unit scale, (c) novel power dense macro-porous PCM structures at encapsulation scale, and (d) interface scale experimental melt interface tracking by advanced tomography techniques for high-temperature PCMs.A megajoule scale high-temperature LHTES modular LHTES test-bed was built and tested, for charging-discharging at temperatures up to 950 K with aluminium alloy PCM encapsulated in stainless steel and air as the heat transfer fluid (HTF). Engineered open-cell cellular ceramic lattice were used as porous fins for enhancing the HTF-PCM heat transfer. Successful first operation was demonstrated with near-isothermal discharge for 2.7 hours in a 1.31 MJ storage. A quasi-1D lumped parameter model was developed and validated to quantify its thermal stratification, heat losses, and phase change characteristics. Heat storage characteristics of scaled configurations of the test-bed were predicted using the model.A 2D transient phase change model was used to compare a high-conducting, high melting point aluminium alloy PCM with a commercially available low-conducting, low melting point paraffin wax to quantify the effect of PCM properties, encapsulation shape, load conditions, and buoyancy driven internal convection on the power density. Parametric study and non-dimensional analysis quantified the influence of thermal and geometrical parameters on phase change and contribution of natural convection inside the encapsulations linking the melt fraction and heat transfer rates to combination of Fourier, Stefan, Rayleigh and Nusselt numbers.With high-conducting PCMs, the LHTES power density is limited by HTF-PCM convective heat transfer which can be enhanced by using novel macro-porous encapsulation designs. A comparison of several random and ordered macro-porous cells was performed with a 3D coupled CFD-phase change model. A mesh-based convolutional neural network was trained to emulate the 3D model and predict phase change time and pressure drop characteristics. Finally, a synchrotron source X-ray tomography experimental campaign to create a validation case for phase change models of high-temperature PCMs is detailed. Transient 3D melt interface tracking was conducted for aluminium alloy in cylindrical encapsulations heated using lasers. As the beamline was limited to small samples, a furnace heating setup was also built for radiography experiments of larger cubic samples at a tabletop CT facility.This thesis presents a combination of modelling frameworks and experimental setups to provide general understanding of transient heat transfer in PCMs at different scales, provide novel approaches for heat transfer enhancement, and tools for designing high-temperature LHTES systems.

EPFL2022

Unpacking the Green Economy concept: A quantitative analysis of 140 definitions

Marta Giulia Baldi, Albert Merino, Romano Tobias Wyss

Over the past ten years, the Green Economy (GE) concept has gained momentum in both academia and policy-making arenas, leading to international programs in diverse sectors and driving national agendas all over the world. The concept is however highly controversial, partly due to its theoretical blurriness. The aims of this article are to shed light on the conceptual ambiguities surrounding the GE and to clarify its distinctive components. More concretely, the paper aims at understanding what GE definitions have in common as a conceptual whole (that is, which key features do they share?), and what makes them different to each other. For these purposes, the present study relies on an extensive review of both academic and grey literatures. Such a review yielded 95 GE definitions, as well as 45 definitions of Green Growth (GG), which is often interchangeably used with the former. All the definitions were methodically translated into a coded format thanks to a conceptual framework inductively developed by the research team. They were subsequently analyzed through descriptive and inferential statistics, as well as network analysis. Results provide the basis for a common meta-understanding of the GE concept. Like Sustainable Development (SD), the GE is a multidimensional notion, whose focus is on the potential trade-offs and synergies between economic and environmental dimensions (without ignoring social issues). The results uncover several discourses underlying the GE narrative, such as “econocentric incrementalism”, “unlimited eco-efficiency” and “transformative GE”. The analysis outlines several key cleaving elements discriminating GE definitions, like the focus on either well-being or economic growth, or the consideration or not of environmental limits. Finally, GE definitions are put into a broader perspective according to their potential as theoretical backgrounds for handling the social-ecological challenges posed by the Anthropocene.