Lighting in Design February-March 2016

It’s difficult to see this as being a low-cost solution and, given the research into LEDs, even as efficiency increases in this process, so will that for LEDs. Yet … yet, there is the emission spectrum that comes from incandescent lighting that is still un- matched by either fluorescents or LEDs. Museums and galleries still prefer the colour presentation of incandescents. And many people are terrified of the mercury in CFL bulbs (which you’d only be exposed to if you broke the damn things … but this does happen). One of the more tricky problems, though, is that EU legislation has banned incandescents rather specifically. Many countries have legislated for a specific efficiency level (such as 15 lumens perWatt, in Australia) which would suit the MIT prototype just fine (at about 45 lumens perWatt, with a theoretical limit of 272 lumens per Watt). “LEDs are great things, and people should be buying them,” says Solja Č i Ć in MIT News. “But under- standing these basic properties about the way light, heat, and matter interact and how the light’s energy can be more efficiently harnessed is very important to a wide variety of things.” The question is: what things? At the moment the limiting factor for widespread LED adoption is simply cost. Compact fluorescents are cheap and long-lasting (and legally mandated over incandescent lamps).The colour balance is gradually being improved. And LEDs are getting cheaper and better. Prob- ably far sooner than these reabsorptive (vampiric? what name should we use?) incandescent lamps will become sufficiently cheap to use. However, there is a market. Much as my wife loves the look and feel of the squirrel cage incandes- cent lamps that hang in our home, people still love the physicality of seeing a real filament inside a real glass enclosure. Light isn’t only about luminance; it’s about the feel of a venue and the expression of personality. Plumen, a British company, specialises in pro- ducing designer low energy lamps, including its signature interlocking looped CFLs. It has created an artistic LED lamp as well. All of these are attempts to add warmth and emotion to something that almost seems wired into our biology. Not for nothing is the symbol of hav- ing a sudden spark of inspiration the incandescent lamp. There will be a market for these proper, more efficient incandescents. And, with a glance to my teacher, I can see I have finally delivered. Let a million lamps lume.

A proof-of-concept device built by MIT researchers demonstrates the principle of a two-stage process to make incandescent bulbs more efficient.This device already achieves efficiency comparable to some compact fluorescent and LED bulbs. Image: Courtesy of the researchers (MIT).

Front view

Cross section

A schematic diagram of a new type of filter that could revive incandescent lighting and make possible more efficient solar electricity generation. The schematic shows the technology from a front and side view (Purdue University-MIT Image/Peter Bermel).

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LiD FEB/MAR 2016