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Questions
Published in Michael de Podesta, Understanding the Properties of Matter, 2020
An incandescent light bulb is essentially a heater: a small section of wire – the filament – is heated until its temperature is sufficient to cause it to glow. You might be surprised at how hot the filament becomes: in most light bulbs the temperature is around 1700 °C! Such extreme temperatures are required because the hotter the filament, the ‘whiter’ the light. However this requirement severely restricts the materials that can be used for a filament. Most commonly, the element tungsten is used. Let us try to work out how to design a filament for a 60 watt light bulb to operate from a 220 V supply. This is the kind of light bulb you might be using in a desk lamp as you read this. It might not seem to be much of challenge to ‘design a piece of wire’ but as you will see, working out the length L and diameter d of the wire is more complicated than it seems.
Sustainable Energy Plans
Published in John C. Ayers, Sustainability, 2017
Next, an easy way to increase the energy efficiency of your home is to switch from old fashioned incandescent bulbs to Compact Fluorescent Lights (CFLs) or Light-Emitting Diodes (LEDs). Artificial lighting accounts for 10% of the energy consumed in the average home, and improving lighting efficiency can reduce that energy by 60% to 70%.14 CFLs are ~5 times and LEDs are ~6 times more efficient and last much longer than incandescent bulbs do.15 Substituting a standard 13 watt CFL for an incandescent bulb will reduce electricity bills by roughly $30 over the bulb lifetime, which easily repays the higher cost of the bulb (Brown 2009).16 Shifting from incandescent bulbs to CFLs in homes, advanced fluorescent bulbs in commercial buildings, and LEDs in traffic lights17 would “cut the world share of electricity used for lighting from 19% to 7%… and save enough electricity to avoid building 705 coal-fired power plants” (Brown 2009).
Natural Light-Style Organic Light-Emitting Diodes
Published in Zhe Chuan Feng, Handbook of Solid-State Lighting and LEDs, 2017
Jwo-Huei Jou, Meenu Singh, Yi-Fang Tsai
Subsequently, the efficiency of the sunlight-style OLED was significantly enhanced from 2.2 to 30 lm/W at 100 cd/m2 as the electro-fluorescent emitters were replaced by their phosphorescent counterparts. Moreover, the phosphorescent OLED device also demonstrated a relatively high efficiency, even at 10,000 cd/m2. This may provide an energy efficient alternative to incandescent bulbs, whose power efficiency is 10–15 lm/W. As to the lower color-temperature range, it may be suitable for lighting at night to minimize blue hazard.
Cytotoxicity and genotoxicity of light emitted by incandescent, halogen, and LED bulbs on ARPE-19 and BEAS-2B cell lines
Published in Journal of Toxicology and Environmental Health, Part A, 2018
Marta Gea, Tiziana Schilirò, Paola Iacomussi, Raffaella Degan, Sara Bonetta, Giorgio Gilli
In the past century, conventional incandescent bulb was almost the only source of electric light used in households. Due to energy saving policy (Commission regulation 244/2009), conventional incandescent bulbs (and other inefficient lighting methods) had to be phased out until September 2012. Incandescent bulbs have to be replaced with energy-efficient light sources such as halogen bulbs, compact fluorescent bulbs (CFLs), or light-emitting diode (LED) bulbs . All these light sources are extensively used for public and domestic lighting, but for the future, it is planned to replace halogen bulbs and CFLs with LEDs (Necz and Bakos 2014).
Utility and consumer-oriented multi-criteria assessment of residential light bulbs available on the Australian market
Published in Australian Journal of Electrical and Electronics Engineering, 2018
Muhammad Usman, Farhad Shahnia, GM Shafiullah, Ali Arefi
The number of residential premises has been growing significantly over the last few years in Australia. As an example, the Housing Industry of Australia (HIA) has reported that 90–120 thousand dwellings have been built every year in Australia since 2010 (‘Window into Housing’ 2015). In some capital cities such as Sydney and Perth, over 30 thousand houses have been constructed in one year (Hennessey 2015; Duke 2016). Also, the average size of a new Australian house has increased by over 40% from 162.2 to 227.6 square meters between 1984 and 2003, which becomes almost 10% bigger than that in the United States of America (US). Different types of electrical appliances are used in residential premises; among which lighting load is the fundamental and unavoidable one. Considering the above factors, the lighting demand illustrates a growing trend in the Australian residential electricity sector (Sorensen 2013; Johanson 2011). Before 2011, Australian houses could consume up to 25 W electricity per square meter (W/m2) of their house floor space (‘BCA lighting restrictions’ 2017). Conventionally, incandescent light bulbs were the main source of lighting but not very efficient as they have only 16 lm/W on average and 95% of the consumed energy was wasted as heat (Wells 2013). However, with the development of a new regulation on using energy efficient lighting systems in residential premises by the Building Code of Australia (‘BCA lighting restrictions’ 2017), this has been reduced to 5W/m2 for indoors, 4W/m2 for outdoors, and 3W/m2 for garages. This new Building Code has significantly pushed the new house builders and those renovating (over 50% of a house) for using energy efficient lamps which have a minimum of 27 lumens per Watt (lm/W) such as compact fluorescent lamps (CFLs) and light-emitting diodes (LEDs) that have an average of 60 and 150 lm/W, respectively (see Figure 1) (Wells 2013; ‘Energy efficient lighting…’ 2013; ‘Lighting Catalog…’ 2013). The estimation of (‘Phase out of…’ 2017) shows that this will reduce Australia’s greenhouse emissions by 800,000 tons, equal to a saving of approximately 0.14%. In a similar way, many countries in the world have already phased out the use of incandescent light bulbs (see Figure 2 (Kooroshy et al. 2015)) by adopting regulations on banning their production, import, and sale for general lighting purposes (Matvoz and Maksic 2008). As an example, incandescent light bulbs of 40 W and above are banned across the US since 2014 by which the nation’s electricity consumption has reduced almost $10 billion every year (equal to the saving from 30 power plants across the country) (Bravo and Abed 2013). Following these bans, CFLs and LEDs have gained a large acceptance and interest among the people; even though their costs are slightly higher.