Climat océanique | EPFL Graph Search

Le climat océanique, selon la classification de Köppen Cfb, également connu sous le nom de climat maritime, est un climat tempéré humide qui se caractérise par des hivers doux et humides et des étés plus frais que pour les climats subtropicaux (climat méditerranéen et climat subtropical humide) et avec un temps variable, sachant que le maximum de précipitations se produit durant la saison froide. Il se rencontre sur les façades occidentales des continents, entre des zones à climat méditerranéen en se rapprochant de l'équateur et les zones à climat polaire en se rapprochant des pôles. Le climat océanique est plus doux et bien moins extrême que le climat continental mais moins chaud que le climat méditerranéen. Il correspond au climat typique de l'Ouest de la France et de sa longue façade océanique bordant l'Océan Atlantique, de la Normandie au Pays-Basque. vignette|Carte du monde montrant les zones bénéficiant d'un climat océanique, les climats océaniques en pleine zone intertropical

Solar energy potential at the Great St Bernard Pass

Pietro Florio, David Notzon, Josef Andreas Schuler

The historical site of the Great St Bernard Pass, situated in the Alps at an elevation of 2469 m, records very high electricity consumptions. This study aims at evaluating the photovoltaic potential at the pass. The analysis was performed on the envelope surfaces of the building complex, taking into account the topography as well as typical climate data issued from a weather station located on site. It is found that during the months from June to October, each year, 54 MWh of electricity could potentially be generated, which is more than what could be produced by the same system in the climate of Geneva.

IOP PUBLISHING LTD2021

Toward Assessing the Sensitivity of Buildings to Changes in Climate

Sönke Frederik Horn

A building is designed for one set of typical climatic conditions. In the context of expected climate change, substantial numbers of existing and new buildings are expected to survive long enough to experience perceptible shifts in climate ‘normals’ (averages). This is problematic for predicting building performance, largely because the exact nature of climate change is hard to predict with certainty. Thus an optimal design is not only tuned to the original design conditions, but is also robust to changes in climatic conditions in the sense of a low sensitivity of its performance. To predict a building’s response to changes in typical weather, two inputs are required: weather data representing this change, and suitable metrics to compare building performance across different climate normals. This report presents initial work on a proposed method for assessing the sensitivity of new or existing buildings to climate change. This method begins with a selection of weather files to represent climate change, then quantifies a building’s passive performance in those climates using an enthalpy-based metric, and ends with a graphical analysis of the performance of the building in different climates to assess its robustness. In this report, we propose an objective performance metric based on the extent to which a building creates indoor conditions passively, i.e. without auxiliary systems. Initial work suggests that the performance assessment carried out here is reproducible and applicable for indoor environment design and evaluation in different ranges of climate change. This approach enables a comparison of building performance without the bias introduced by inherent differences in climatic conditions.

2013

The role of Encapsulants in the long-term performance of advanced Crystalline Silicon Glass-Glass PV modules

Luca Gnocchi

The adoption of crystalline silicon (c-Si) PV modules based on glass-glass (G-G) structures is gaining momentum because of the possibility to manufacture bifacial panels, collecting light from the rear side. Despite not being an optimal material, Ethylene Vinyl Acetate (EVA) has become the dominant encapsulant in the PV industry. In fact, upon exposure to UV at high temperatures in the presence of moisture, EVA generates acetic acid (HAc), leading to the corrosion of the metallic interconnects. This problematic may be even more pronounced in a non-permeable G-G structure, compared to a conventional glass-backsheet (G-BS) design, in which HAc can be partially degassed out through the breathable BS. Nevertheless, some industries would like to continue using EVA in the manufacturing of G-G modules, because of the lower cost, the much longer track record and easier processability of EVA compared to newer alternatives, such as polyolefns (POs). In this work, we try to answer the question whether it is possible to use EVA in the manufacturing of G-G modules. The experimental chapters focus primarily on study the long-term reliability, in particular:1. The sensitivity to water of different c-Si cell technologies (i.e. Aluminum Back Surface Field (Al-BSF), Passivated Emitter Rear Cell (PERC) and Silicon Heterojunction (SHJ)) exposed to damp-heat, where we highlight the good stability of the EVA, and the sensitivity to moisture of the SHJ solar cells.2. We propose a detailed microscopical model explaining the problematic of the SHJ to water. In reality, the presence of moisture (favored by the use of EVA) is only a contributing factor, as clearly indicated by the fact that the degradation in more pronounced in the presence of glass. Here we point at the role of a glass corrosion process and of NaOH in damaging the passivating properties of the cell. Either by reducing the water ingress (with an edge seal or a PO) or by replacing the glass type, the degradation phenomenon is not observed.3. The impact of EVA storage conditions on the lamination quality and ultraviolet (UV) degradation. If good polymer storage and handling practices are carefully respected, the results tend to suggest that EVA can still be a viable solution to encapsulate G-G PV modules, for deployment in geographical zones where the humidity levels are not so high during the year (i.e. temperate climates). On the contrary, if these conditions are not observed, or in the event of module operating in a hot-humid climate, we believe that this may affect the long-term performance of G-G modules encapsulated with EVA.4. An accelerated aging test for acetic acid corrosion (missing in the industry standards) is developed to probe wear-out and end-of-life behavior and facilitate screening of metallization, and interconnection technologies. Corrosion is in fact one of the main end-of-life failure modes in PV modules which use EVA. Here, SHJ cells with a low temperature silver paste-based interconnection outperformed cells with conventional solder-based interconnection (i.e. Al-BSF and PERC). The proposed corrosion test method can be optimized to match corrosion behavior observed in feld modules with shorter times than standard damp heat tests.These results give us a deeper insight on how to manufacture reliable and durable G-G modules, based on different cell technologies, and do not rule out the possibility to use EVA when targeting extended lifetimes of double glass panels.

EPFL2022

The role of Encapsulants in the long-term performance of advanced Crystalline Silicon Glass-Glass PV modules

Luca Gnocchi

EPFL2022