Readers might recall I was an early adopter of LED lighting technology. Now it is getting even better.
New LED light design offers less energy, more light
LEDs are durable and save energy. Now researchers have found a way to make LED lamps even more compact while supplying more light than commercially available models. The key to success: transistors made of the semiconductor material gallium nitride.
Incandescent light bulbs are now banned in the EU, while energy-saving lamps remain a bone of contention. In 2016, it will be lights out for halogen bulbs over 10 watts as well. LEDs (light-emitting diodes) therefore have the best chance of becoming the light source of the future. Experts reckon that LED retrofit lamps for use in standard bulb fittings will overtake traditional energy-saving bulbs for the first time from 2015. By 2020 it is predicted that LEDs will have captured between 88 and 90 percent of the lighting market. The tiny diodes offer a whole host of advantages as the most environmentally friendly source of light – they contain no harmful substances, consume less energy and, with a lifetime of between 15,000 and 30,000 hours, last longer than conventional light sources. They also work at full brightness as soon as you flick the switch.
Coping with higher temperatures
LEDs do have one weakness, though – they are extremely sensitive to variations and spikes in power. To function properly, they need a driver that ensures a constant supply of power at all times. This driver, which takes the alternating current from the grid and converts it into direct current with a reduced voltage, has a profound influence on the light yield and lifetime of the LED lamp as a whole. The demands placed on the driver electronics are correspondingly high. This has prompted researchers at the Fraunhofer Institute for Applied Solid State Physics IAF in Freiburg to focus their attention on voltage transformers featuring gallium nitride (GaN) transistors. During practical testing, the scientists found that the drivers developed using this new semiconductor material were extremely robust. Components made of GaN can operate at higher currents, voltages and temperatures than standard silicon transistors. “Heat plays a role both in the brightness and the service life of LED lamps,” says Dr. Michael Kunzer, group manager at Fraunhofer IAF.
Gallium nitride transistors switch at high speed
Gallium nitride transistors can also switch at high frequencies. The switching speed has a significant impact on the size of the coils and condensers built into the drivers for energy storage. In a GaN-based driver, the switch speed can be made as much as a factor of 10 faster than that of its silicon equivalent. “Applied to a smaller surface, this means it is possible to make switching cheaper. The whole LED lamp can be made lighter and more compact while delivering the same or even improved illumination,” explains Kunzer. Since the energy storage component plays a decisive role in manufacturing costs, this could have an extremely positive effect on the end price.
Thanks to the new semiconductor material’s useful properties, Kunzer and his team have been able to boost the efficiency of the GaN driver to 86 percent – between one and four percentage points better than its silicon equivalent. When compared with the silicon transistor LED lamps available on the market., the scientists were able to increase the light output: while the luminous flux of commercial LED retrofit lamps featuring silicon components is around 1000 lumen (the unit used to measure the light produced), researchers from the IAF have been successful in increasing this to 2090 lumen. “20 percent of energy consumption worldwide can be attributed to lighting, so it’s an area where savings are particularly worthwhile. One shouldn’t underestimate the role played by the efficiency of LED drivers, as this is key to saving energy. In principle, the higher the light yield and efficiency, the lower energy consumption is. If you think that by 2020 LEDs will have carved out a market share of almost 90 percent, then it is obvious that they play a significant role in protecting our environment,” says Kunzer. The researchers will be showcasing a demonstrator of their retrofit LED from April 7-11 at the Hannover Messe, where they can be found at the joint Fraunhofer booth in Hall 2, Booth D18.
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I replace about 4 or 5 incandescent bulbs a year. When they were due to be phased out I went out and bought enough bulbs to see me out. At the time I was buying two 100w bulbs in a pack for 38 cents (euroland) thanks to them being phased out.
During the summer we are outside much of the evening, so lights are not used for long periods. During the winter, the lights go on when it gets dark and generally the extra heat given out means that no heating is required despite sub zero temps (oil central heating – much more expensive than the lighting). Here in France the electricity (mostly nuclear) is relatively cheap – once the relevant extras are taken into account about ten euro cents per Kwh (cheap rate after ten pm) and sixteen euro cents during peak hours.
I can’t imagine switching over to any other form of lighting anytime soon. I prefer the light, the response time and I believe I am using less total energy hence saving money. Win/win/win.
SteveT
I have two twisty bulbs still in the package. Why? The dim light panel in the bathroom will not be made brighter by replacing the burned-out twisties with new yet still dim twisties. It just isn’t worth the hassle of getting a big ladder into the bathroom.
Years from now the stories in childrens’ books will be about some famous president who as a child was trying to read by the dim light of a twisty.
Love LED bulbs. Put them in everywhere in my house I could. It’s about being $$ smart, not Carbon stupid.
Went with the twistys (whole house) when they came out years ago.
Power bill went down $10.00 per month. Only had 3 fail in all that time and they get left on a lot.
(I have one in a back yard fixture going non-stop for 5 years)
The only thing stopping me from going LED was the color temperature….
Just bought 2 nice 3700 deg. kelvin 60 watt equivalent Cree LED bulbs at Lowes less than $10.00 ea. They give the same light as the 60 watt incandescents we all know and love !!!.
So I’ll be swapping out again.
A somewhat minor edit suggestion. The article states “the luminous flux of commercial LED retrofit lamps featuring silicon components is around 1000 lumen”. This amount of lumen is currently available in a 10-12 watt LED bulb. A currently available 60 watt LED bulb may have 4000-6000 lumen (ie 100 watt/lumen).
@Dennis Kuzara: “The typical LED switching power supply will be a few ten to a few hundreds of KHz. The only reason someone would want to use a GaN tranistor is because they have lower parasitic capacitance compared to a Mosfet, but that only matters in the high Mhz to GHz range. Using a GaN transistor makes no sense, and it will have no effect on the efficiency of the LED. There is no way using GaN transistors can do anything significant, let alone double the power output of the LED.”
Unless I misremember, don’t GaN transistors have a lower Rds ON that MOSFETs? Lower On resistance means less energy loss from heat which in turn means higher efficiencies, all other things being equal.
With higher switching frequencies on the power supplies I would think standard MOSFETs would do the trick, though they would generate a little more heat than GaN FETs.
Do we still know what we are buying when we acquire CFLs or LEDs?
Earlier, when we bought incandescent light bulbs, we knew exactly the color rendering index (CRI), the power factor (PF), the spectrum that is similar to the setting sun. Buying modern lamps, the CRI is lower (about 80%), the PF is very reduced, the characteristics of the spectrum is not indicated: Which colors are predominant? Which hues are absent? What’s the share of the blue color in the spectrum? It is very important to know this share because if it is too high, the lamp may not be used at evening because of health reasons.
Moreover, the life time of the lamps has become a matter of statistics. In Europe, it is considered as ‘normal’ that 10% of the LEDs fail before 6,000 hours, that 20% of the LEDs do not maintain the prescribed luminance after 6,000 hours burning!
Conclusion: Buying a modern lamp is purchasing a product of poor quality regarding CRI and PF. And is taking part in a lottery regarding the life time. The rights of the consumer are denied blatantly.
I haven’t been able to find a dimmable LED light that I like as much as incandescents. That being said about half the lights in my home are LEDs. Unfortunately I also have a few fixtures that are CFL only, which are a total nightmare and don’t seem to work even when I buy the appropriate goofy-pronged replacement bulb. ANYTHING is better than CFL, the sooner we get rid of them the better.
In a cold country LEDs don’t save energy. They provide heat when and where it is needed and otherwise don’t, i.e. they save energy in the same way as ventilation controlled by presence of people in a room. The “saving” LED provide assume people don’t put up their thermostats when the room they sit in becomes colder. All practical experience speak to the opposite. Which you can see from actual energy use in residential homes: it has increased.
My previous comment was WAY up in the list! Usually I’m one of the last to reply to a thread. But here is my second comment:
#1 I agree with the free-market libertarian comments that the issue ought to be decided by personal buying choices. One size does NOT “fit all!”
#2 On the other hand, as a very minor former player in local politics, I will state that UNFORTUNATELY a majority of the population in the USA does not give a rats ass about anything until it becomes a personal problem/irritant. One reason there are so many nuclear power plants is that in decades gone by –due to subsidies and tax breaks– they provided an “easy” way to increase electrical power generation. THE FACTS that decades later these “easy” solutions to boosting power generation would incur billions of dollars in costs for nuke waste management, cleanup were NOT subject to public debate at the time. This does not even begin to address the incalculable costs of things like Fuk-U-shima polluting the entire North Pacific ecosystem.
–Therefore, it is in the public interest to reduce electrical power usage. Being an old git on a very meager US SSD income, I’m personally not fiscally in favor of _really_ charging me what electricity costs to generate and distribute. But most people have no real idea of how unrealistic their current energy costs are. Unfortunately for me and others, reality is what it is.
My bottom-line comment is a pessimistic list. I think it would be best if :
A] All Nuke power plants were decommissioned ASAP.
B] Existing shareholders of the corporations owning these plants bore the brunt of the cost.
C] All Government (politically motivated) subsidies be abolished in the energy markets.
D] Let people decide for themselves whether they want to pay 4-5X the REAL cost in electricity for incandescent bulbs as opposed to LED lighting.
E] CFL’s are mercury-laden toxic hazards. Under any logical application of existing law, they are to be banned. It’s only due to political influence that they are on the market at all.
I can go on and on. But since my appointment as Ruler of the World is still pending, I’d just like to say:
Go Anthony Watts! Go Steyn! Let’s use rational science –and let the chips fall where they may.
. . . and IT’S ALL subject to debate!