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Because several ACerS members are directly or indirectly involved with LED research and development, and because I am doing some remodeling at my house, I figured that now would be a good time to investigate what reasonable LED options are available for residential lighting. I was even willing to fork over some extra cash for the inevitable premium price being charged for home LEDs, as long as the performance was good. Unfortunately, my experience was disappointing.

Obviously, LEDs are starting to make inroads in niche residential applications such as exterior holiday lights. But I wanted something more typical and useful from my perspective: A replacement for a 65-75 watt incandescent in a ceiling recessed-can fixture. Typically, these fixtures use “floodlight” type bulb. I limited my shopping to big box outlets, lighting stores and local hardware stores. (I did peak at Amazon and eBay to see what might be available, and the choices/prices/shipping hassles didn’t seem to justify taking that route.)

I ended up selecting what was described as an 18-watt indoor floodlight for about $40. When I screwed it in, the light was, uh, overwhelming. I felt like I was suddenly in one of those movie scenes where the detectives are interrogating a suspect under the glare of a single bright lamp. It certainly was bright, but only in an annoyingly focused small area. It made me think that instead of “floodlight,” the manufacturer meant spotlight.

Actually, I wasn’t totally surprised. It seems the difficulties of diffusing LED light is a known problem that has been a limiting factor with widespread LED adoption. I just hadn’t realized how huge of a problem it is for consumers and manufacturers.

But apropos to all this, and totally by coincidence, I came across this recent announcement from Panasonic touting that its new LED bulbs and lamps illuminate much larger areas. One of the products looks like a bulb; the other is a squarish, flattish ceiling lamp.

I am not sure I understand Panasonic’s approach, so I am going to rely on the description provided by Nikkei Monozukri’s Masaru Yoshida. Regarding the “Everleds” bulb (concept illustrated above), Yoshida says Panasonic gets around the narrow light distribution angles this way:

“[The] light source (LED package) is arranged in a circular shape inside a globe (a semi-spherical cover) and two light reflectors with apertural areas are used. The light from the LED package is reflected on the first light reflector to the back direction (normally to the side of the ceiling). And part of the light passing through the apertural area is reflected on the second reflector to the side. The light traveling in a straight line is diffused by the semi-spherical globe. As a result, it becomes possible to realize a light distribution angle as wide as that of an incandescent light bulb. […] Panasonic took measures to improve heat radiation. It arranged the circuit of the light bulb so that driver chips and other heat-sensitive components are located near the center of the circularly-arranged LED package, where temperature is relatively low.

The ceiling lamp’s operation is different and requires two LED modules. Again from Yoshida:

“One is mainly used to directly light the entire room by emitting light downwards (direct light module). And the other lights the ceiling and walls (indirect light module). […] Specifically, the LED module for direct light is placed in the four sides of the quadrangular ceiling light with its light-emitting area facing the inside. And light is emitted downwards from the module by using the reflector and the light diffuser located below the reflector. On the other hand, the LED module for indirect light is placed on the LED module for direct light, facing outward, so that light spreads horizontally. In addition, each module is equipped with two types of LED packages: a daylight-color LED package and an incandescent-color LED package.

For an Everled bulb equivalent to a 60-watt incandescent, the estimated price is around $45. The ceiling lamp (below) initially might sell for $600 (yikes!) Neither appear to be available in the U.S. market yet, but are likely to arrive sometime in the next 12 months.

As for now, I am returning my LED bulb and plan on waiting another year before I try again.

Credit: Panasonic

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Via Fast Company, artist-designer Wendy Legro’s concept for a mechanical/electronic LED “morning glory,” one-at-a-time or in an array, displayed at the Design Academy Eindhoven exhibition at Milan Design Week 2010:

[Legro] wants to reintroduce the sun’s natural source of light back into our lives. ‘morning glory’ consists of mechanical flowers which are triggered by a light sensor. by day, the flowers are closed, allowing the sun to shine in, and after sunset they open up and radiate light as they begin to cover the window.

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The title of this post may sound like it’s a statement of the obvious. Sure, compact fluorescent bulb and LED’s use far less energy to generate an equivalent amount of light in comparison to standard bulbs. But whether one is looking at electric buses, batteries or bulbs, a much broader – and ultimately more important – question is the total energy usage of a product over its full life cycle, viz., the energy required to manufacture, operate and finally dispose of it.

So, looking at this bigger picture, how do LEDs and CFLs fare? OSRAM Opto Semiconductor says its got the answer.

The company published a study a few days ago reporting on a full life-cycle assessment of each of the lights and the bottom line, according to the study, is that filament bulbs require about five times the energy that CFLs and LEDs use.

Now, admittedly OSRAM-OS is in the LED business, so the doesn’t directly promote the use of CFLs. In fact, the long-term battle for LED makers isn’t to challenge the performance of filament bulbs but to challenge CFLs as the best alternative to filaments. Having noted that, it’s worth taking a look at the following findings from the report:

• Less than 2% of the total energy demand is needed for production of the LED lamp
The manufacturing phase is insignificant in comparison to the use phase for all three lamps as it uses less than 2% of the total energy demand. This study has dismissed any concern that production of LEDs particularly might be very energy-intensive. Merely about 0.4 kWh are needed for production of an LED (OSRAM Golden Dragon Plus), about 9.9 kWh for the production of the Parathom LED lamp including 6 LEDs.

• LED lamps are competitive to CFL today
In contrast to the primary energy consumption of incandescent lamps of around 3,302 kWh, CFL and LED lamps use less than 670 kWh of primary energy during their entire life. Thus 80% of energy can be saved by using CFL or LED lamps. The bottom line is that LED lamps are more efficient than conventional incandescent lamps and also ahead in terms of environmental friendliness. Even today, LED lamps show nearly identical impact on the environment compared to CFL.

• Future improvements of LED lamps will further cut down energy demand
As the efficiency of LEDs continues to increase, LED lamps will be capable of saving more
energy and achieving even better LCA results in future.

An executive summary of the study is available here.

The timing of the study seems a little odd. It appears from the OSRAM-OS website that the study was completed in August. A press release indicates that it was to be sent out for independent verification and, following that, publication in October. However, the study wasn’t posted until Nov. 30. Indeed, the study now includes information that the results were certified by Matthias Finkbeiner, TU Berlin (Germany); Stig Olsen, Danmarks Tekniske Universitet Copenhagen (Denmark); and Jens Hesselbach, Limón GmbH (Kassel, Germany).

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I’m not sure if this Solar Roadways concept is insane or brilliant, but I think my gut reaction is that this is generally far fetched – at least on the scale these visionaries are thinking about. Having noted that, I also think it might be useful for some specific roadway signage applications in the short run. Regardless of my thoughts, however, the SR idea apparently made enough sense to the U.S. Department of Transportation to get the agency to tentatively agree to give a $100,000 SBIR Phase I grant to the Idaho-based SR group to build a prototype.

Here is SR’s idea: Create full roads out of structurally-engineered solar panels. Yes, they would be driven on! These panels would provide a road surface, and collect and store energy to a LED transportation communications system built into some of the panels. Excess power would be pushed into the grid for residential and commercial use.

SR proposes making three-layered panels:

• The surface layer: Traction-designed, weatherproof and translucent. High-strength glass?
• The electronics layer: Primarily the PV layer, but with LEDs for “painting” and signage built into the road surface, and ultracapacitors for energy storage.
• The base plate layer: This layer insulates the upper layers, and distributes power and data signals.

SR says that it expects that each panel could produce 7600 Wh and 3.344MWhr per lane, per mile of electricity based on 15% efficiency and four hours of sunlight per day (for more details, see their Numbers page).

The issue of glass strength isn’t really addressed head on by SR. An FAQ on SR’s website has some discussion about traction issues, and mentions that presentations have been made at an International Workshop on Scientific Challenges for New Functionalities in Glass workshop and to Penn State’s Materials Research Institute, but fails to making a convincing case about whether current glass materials are up to the task that the SR concept poses.

One of SR’s weaker arguments is that the group envisions these panels as needing little maintenance (”Hey - we can use self-cleaning glass technology!”) and eliminating snow plowing (”Hey - they can heat themselves. No more snow/ice removal and no more school/business closings due to inclement weather!). For a company based in Idaho, they seem oblivious to the notion that state DOTs spend a lot of time and money on snow and ice removal despite (and because of) the fact that current roadways act already as heat sinks. SR panels would also be vulnerable to snow drifting.

Here is Scott Brusaw, one of SR’s key figures, discussion the proposition:

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Lumenhaus is Virginia Tech’s zero-energy home that can be completely powered by the sun and geothermal energy. Other sustainable features include the use of passive energy systems, radiant heating and building materials made from renewable and/or recyclable sources.

The College of Architecture and Urban Studies is entering the house in the U.S. Department of Energy’s Solar Decathlon 2009.

The house will be displayed outside the National Building Museum in Washington, D.C. for most of September. In October, Lumenhaus will be on display at the National Mall along with other entrants in the Solar Decathlon. And, Virginia Tech is one of only two U.S. universities invited to compete in the first Solar Decathlon Europe, which will take place in Madrid in June 2010.

A powerful array of photovoltaic panels provides carbon-neutral energy to the house. The PVs, arranged in a single array that covers the roof, are built into the house during construction. The panels are bifacial, meaning they use both sides to increase energy output by up to 15 percent. Using an electric actuator, the entire PV array can be tilted to the optimal angle for each season (from zero degrees to a 17-degree angle in summer and to a 35-degree angle in winter).

The energy collected during the day will be radiated back out at night through a low-energy, long-lasting LED lighting system.

Lumehaus is not only energy-efficient; it is water-efficient, too. The roof is sloped to collect rainwater that is filtered for potable use in the house, while used household greywater – from the shower, bathroom sink and clothes washer - goes through a series of bio-filters in the surrounding landscape where it is cleaned for non-potable use.

Lumenhaus facade uses aerogel as an insulator that allows natural sunlight in the house while insulating against the harshest conditions. (Credit: Virgina Tech)

An advanced building façade is comprised of two independent layers: a metal shutter shade and a translucent insulating panel. The shutter shade slides along the north and south façades, providing protection from direct sunlight while simultaneously allowing for indirect, natural lighting, views to the exterior and privacy to those inside. The sliding insulating panel is a translucent polycarbonate panel filled with aerogel. Aerogel provides insulation equivalent to a typical sold wall during harsh weather conditions without blocking natural light.

I don’t know about you, but this is my dream house come to life. If you like it, too, you can even fan it on Facebook.

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