Lighting in Design Q1 2022

Energy-efficient lighting: entering a new era From the moment the first artificial light bulb was introduced, ‘energy-efficiency’ was a major focus area for the lighting industry and significant progress has been made over the years in making lighting more efficient.

S ince the invention of the incandescent lamp, the lighting industry has always been focused on improving the efficiency of its products. For decades this focus rendered little results. The oil crisis in 1973 gave a boost leading to the introduction of the Compact Fluorescent lamp. The conversion from analogue to digital technology (LED) combined with legislation like the ban on the inefficient incandescent lamps changed the energy landscape for lighting and resulted in a significant drop in percentage used for lighting as part of the global electricity consumption, from 19% in 2006 to 13% in 2013 with a further reduction on the cards. This achievement created a perception that lighting has done its part in reducing energy-use in the fight to combat climate change. Nothing is further from the truth as there is still a large potential to further reduce energy-use for lighting. The lighting industry must intensify its efforts in promoting the most efficient LED solutions in combination with control systems, align itself with the trend towards green – and net zero carbon buildings and reach out to other industries to realise potential spin-off effects. This article is part of this awareness creating effort. Lighting and efficiency From the moment the first incandescent lamps were introduced the lighting industry focussed on increasing the efficiency of the lamps. The unit to measure the light output of a lamp is the ‘Lumen’ and the lighting industry uses the ‘Lumen/Watt ratio’ to indicate the efficiency of a light source.

As the light generating principle of an incandescent lamp is intrinsically inefficient (it generates more heat than light) the increase in efficiency over time was limited with the ‘invention’ of the halogen lamp as most important step forward. The introduction of a new light generating principle being the gas discharge principle delivered better results. Fluorescent tubes and High Pressure Sodium lamps used in street lighting are examples of gas discharge lamps. The end of the 70s and the 80s of the 20 th century saw an acceleration in new energy- efficient lighting products. This was the result of the 1973 ‘oil crisis’ in theWestern countries, people realised how dependent they were on oil for energy and transport. This renewed focus on energy- efficiency resulted in the introduction of Compact Fluorescent Lamps, more efficient fluorescent tubes and more efficient (electronic) control gear. Some markets adopted all these new products, other markets considered them too expensive. Another major event took place in the early nineteen nineties when Shuji Nakamura developed the blue LED. This resulted in the commercial use of LEDs (Light Emitting Diodes) in general lighting as it allowed the creation of white light (either by combining blue LEDs with green – and red LEDs or by adding yellow phosphors to blue LEDs). The last 20 years has seen a dramatic increase in efficiency of LEDs (increased Lm/W ratio) while prices have dropped, making LEDs the technology of choice and transforming lighting from traditional

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LiD Q1 - 2022