Éclairage

Résumé

Léclairage est l'ensemble des moyens qui permettent à l'homme de doter son environnement des conditions de luminosité qu'il estime nécessaires à son activité ou son agrément. L'éclairage associe une source lumineuse (naturelle ou artificielle, fixe ou mobile) et d'éventuels dispositifs de type batteries, luminaires ou miroir/puits de Lumière. Historique Les sources artificielles étaient le feu, des lampes à graisse, puis des lampes à huile, des torches, des bougies, les lampes à pétrole puis le gaz, puis des lampes électriques d’abord à incandescence (traditionnelle ou halogène) puis fluorescentes et électroluminescentes. Le luminaire sert à diffuser une lumière produite par une source de lumière artificielle (schématiquement : carcasse + vasque + éventuelle optique, accueillant la source lumineuse). Chronologie des techniques d'éclairage Sources de lumière depuis la Préhistoire

Le Soleil : voilà à peu près quatre milliards cinq cents millions d'années,

Source officielle

https://fr.wikipedia.org/wiki/%C3%89clairage

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Renewable energy deployment and implementation of a circular economy will play a crucial role in decreasing CO2 emissions to meet the target from the Paris agreement. Dye-sensitized solar cells (DSSCs) can be designed in various colors and transparency for building-integrated photovoltaics (BIPV). This emerging technology has gained significant attention for its remarkably high power conversion efficiency (PCE) under indoor lighting up to 34%. To improve the performance of DSSCs, various approaches to study and reduce the interfacial electron recombination from the conduction band of the semiconductor to the electrolyte were implemented in this thesis. One of the approaches was the design of a tandem electrolyte containing two redox species, the radical AZADO (AZ+/0) and the [Co(bpy)3]2+/3+ complex. DSSCs with tandem electrolytes showed increased open-circuit voltage (VOC) up to 1009 mV and enhanced PCE of 9.15%. The VOC enhancement was determined to result from the higher redox potential of (AZ+/0) and the slower electron recombination rate. These findings demonstrate the advantages of employing tandem electrolytes to improve the VOC and overall performance of DSSCs. To decrease the solvent's volatility and the interfacial electron recombination in cobalt-based electrolytes, hyperbranched networks (HB) were designed through a click thiol-ene reaction between a thiol-siloxane and an acrylate monomer. The formed polymers were denoted HB1 (thiol-siloxane and PEGMA) and HB2 (thiol-siloxane and PEGMA). The addition of 20% of HB polymers to a cobalt-based electrolyte retained up to 98% of their initial weight until 150°C. The devices employing 10%(v/v) of HB1 attained the highest PCE under AM1.5 of 8.52%, comparable to 9.36% for the cobalt reference electrolyte. All the HB-electrolytes presented higher VOC values than the cobalt reference due to an upward shift in the CB of TiO2 and longer electron lifetimes. It was determined that the HB-polymers reduce the electron recombination and enhance the photovoltaic performance under low light intensity leading to a PCE of 23.19% under 1000 lux compared to 20.37% for the Co-reference. We then developed a new dye, R7, with a strong electron-donating PAH core and BPT2 as the central building block and a bulkier HF donor to decrease electron recombination at the interface TiO2/electrolyte. We found that in the presence of a copper electrolyte, the dye R7 outperformed devices with R6. EIS revealed that the bulky HF-donor introduction effectively suppressed the electron recombination between the TiO2 surface and the redox shuttle. Additionally, we employed a co-sensitized system of R7+Y123 to reach the outstanding parameters of JSC of 16.15 mAcm-2, VOC of 1035 mV, FF of 0.76 to achieve a top PCE of 12.7%. To the best of our knowledge, this is the highest for copper-based DSSCs using a blue photosensitizer. Lastly, the interfacial phenomena in DSSCs with carbon counter electrodes (CCEs) and copper-based electrolytes were studied to determine the feasibility of the production of monolithic DSSCs with copper-based hole-transporting materials. It was found that the electron transport in devices with CCEs is in the same order of magnitude as those with PEDOT. However, the devices with CCEs presented a decrease of 2 orders of magnitude in the recombination resistance, resulting in decreased VOC and JSC, leading to a PCE of 17% compared to 24.5% for PEDOT devices under 1000 lux illumination.

EPFL2021

Chargement

RSS Range Estimation for Indoor Localization Using LED Lighting

Jun Liu

2014

Chargement

Energetic, Visual and Non-Visual Aspects of Office Lighting

Friedrich Linhart

Light has important visual and non-visual effects on humans and high-quality light should therefore be supplied inside buildings in sufficient quantities. On the other hand, artificial lighting is responsible for a large part of an office building's electricity needs. It is thus important to take into account at the same time visual comfort, non-visual effects of light and energy-efficiency when designing lighting systems for office buildings. The general objective of this doctoral thesis was to combine knowledge from several scientific fields (e.g. daylighting technology, artificial lighting technology, lighting simulation and chronobiology) to discuss how sustainable lighting solutions (i.e. lighting solutions that are optimized in terms of energy-efficiency, visual comfort and performance as well as non-visual aspects of lighting) can be achieved in office rooms. A research strategy that used a test office room equipped with an Anidolic Daylighting System (ADS) as a starting point has been followed. This ADS was shown to be well-accepted by office occupants and to be able to supply sufficient daylight flux during large parts of most working days. Based on this ADS, a highly energy-efficient electric lighting system for complementary artificial lighting was developed and tested in a visual comfort and performance study with human subjects. In addition to that, the chronobiological properties of the test office room were assessed. It was shown that the ADS-equipped room performs extremely well under daylighting conditions in terms of non-visual aspects of office lighting. For the rare times when this is not the case, a back-up system for chronobiological lighting based on blue Light Emitting Diodes was developed. In order to get a deeper insight into chronobiological aspects of office lighting, a first applied chronobiological study at the Solar Energy and Building Physics Laboratory was initiated. Furthermore, possibilities to apply the concepts developed during this doctoral thesis to other types of buildings and other geographic regions were discussed. In conclusion, this doctoral thesis successfully demonstrated that it is possible to achieve sustainable lighting scenarios that are optimized in terms of energy-efficiency, visual comfort and performance as well as non-visual aspects by combining day- and electric lighting technologies in an appropriate way.

EPFL2010

Chargement

Energetic, Visual and Non-Visual Aspects of Office Lighting

Friedrich Linhart

EPFL2010

EPFL2021