13 research outputs found

    Methodology for cost-effective energy and carbon emissions optimization in building renovation (Annex 56)

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    "Energy in Buildings and Communities Programme, March 2017"Buildings are responsible for a major share of energy use and have been a special target in the global actions for climate change mitigation, with measures that aim at improving their energy efficiency, reduce carbon emissions and increase renewable energy use. The IEA-EBC Annex 56 project «Cost-Effective Energy and Carbon Emissions Optimization in Building Renovation» intends to develop the basics for future standards, which aim at maximizing effects on reducing carbon emissions and primary energy use while taking into account the cost-effectiveness of related measures. The IEA EBC Annex 56 project pays special attention to cost effective energy related renovation of existing residential buildings and low-tech office buildings (without air conditioning systems).info:eu-repo/semantics/publishedVersio

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

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    Recycled concrete is now used in many different applications and scientific studies have shown that they have performances similar to concretes which use natural gravel [1, 2]. With the aim to evaluate the environmental impacts of recycled concrete, a life cycle impact assessment (LCIA) has been performed and results compared with those of normal This study is the result of a project involving the “Claie-aux-Moines (GCM)” gravel mining company and the Canton of Vaud to determine whether the impacts of transporting materials are significant for three different concrete production processes. Two relevant environmental indicators in building environment showed that the recycled concrete have relatively less impacts than normal concrete. This study also demonstrated that the material origin should be taken into account in the LCIA as transport distances have a non-negligible influence on the impacts. These findings suggest that recycled concrete could be an alternative solution to normal concrete as it contributes to reduce environmental impacts of buildings and preserve natural resources by reusing recycled gravel resources

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

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    Le projet UserGap propose une approche innovante pour analyser l’écart de performance entre le bilan réalisé en planification et les consommations mesurées lors de l’exploitation des bâtiments à faible consommation d’énergie. Les consommations énergétiques sont désormais de plus en plus sensibles aux hypothèses sur le comportement des usagers et sur le fonctionnement des installations techniques. Les objectifs de ce projet sont 1) de comparer le bilan énergétique planifié avec les valeurs mesurées en exploitation ; 2) de caractériser l’écart de performances et le rôle des utilisateurs sur celui-ci ; et 3) de tester des mesures de réduction de consommation au moyen de « Living Lab ». Pour ce faire, un modèle stochastique de simulation énergétique a été utilisé. Il caractérise une distribution de probabilité pour la consommation énergétique considérant l’incertitude des paramètres de la norme SIA 380/1. En évaluation ex-post, il est calibré en remplaçant certains paramètres variables par les valeurs mesurées in-situ pour approximer la consommation réelle. Cette approche permet de hiérarchiser l’influence des paramètres (technique et utilisateur) sur le « performance gap », et, peut être utilisé: - en conception: pour identifier l’influence de l’usage sur la demande en simulant mensuellement, selon des distributions de probabilité, les paramètres « utilisateurs » ; - en exploitation: pour vérifier les consommations par ajustement du modèle de calcul et proposer des actions correctives sur la consommation via un Living Lab.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

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

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    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

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

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    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

    Optimum environnemental et financier des isolations pour les rénovations

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    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

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

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    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

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

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    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
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