Rectify this

Below is a cut and paste “review” of the idea behind light rectification as an alternative method of deriving electrical power from solar energy. To preempt comments, this is not a magic bullet solution, it is some way yet before it may be useful (if ever) and I am not suggesting that “all our energy problems are over hip hip hooray”. However, IF advances keep apace, the possibility of being able to mass print such a device as envisioned below may be a welcome development.

Rectification is part of the process of converting an AC signal into a DC signal. Simple half wave rectification uses a diode that allows the forward going current to pass and blocks the reverse going current. Additional components are then used to “smooth” the resulting signal. Full rectification uses a bridge rectifier (essentially a collection of diodes) arranged in such a way that both the input forward and reverse currents appear at the output of the circuit in the same direction. Again, when smoothed this becomes a DC current.

Rectification is not a new technology. The simple “cats whisker” rectifier (a piece of wire in contact with a semiconducting crystal) of simple crystal radio sets – perhaps a novelty for the Nintendo generation – was the heart of the detector.

Rectification of microwaves is achievable at high power and is one of the technologies behind schemes to transmit solar power from space to ground based receivers. It has also been demonstrated as a means of wireless transmission.

In theory, the same principle should be applicable to shorter wavelength radiation, if some fundamental limitations can be overcome.

LEDS be realistic

Australia announced its ban of the old incandescent in 2007 and since last year (2010) they are no longer allowed to be sold. Did the ceiling fall in? No.

Incandescent lights used for novelty (decoration) and specialty (fridges/ovens/UV-Vis Spectrophotometers) uses are of course still available.

So I don't understand why banning the wire in a bottle is being reported as such a burning issue in the US. Is it that much of an icon of US invention?

The immediate successor is the CFL, but LEDs are making rapid progress.

Image from Hwa A. Lim, “Eco-fficiency: Green this and green that”, Symbiosis, May/August, 2010.

The life time savings in both energy AND mercury emissions are obvious.
All lights flicker when used on AC so that can't be a real issue, and CFLs and increasingly LEDs are available in a range of colours and improved colour rendering ability.

LED Bulbs Hit 100 Watts As Federal Ban Looms
NPR

Two leading makers of lighting products are showcasing LED bulbs that are bright enough to replace energy-guzzling 100-watt light bulbs set to disappear from stores in January.

Their demonstrations at the LightFair trade show in Philadelphia this week mean that brighter LED bulbs will likely go on sale next year, but after a government ban takes effect.

The new bulbs will also be expensive — about $50 each — so the development may not prevent consumers from hoarding traditional bulbs.

Creating good alternatives to the light bulb has been more difficult than expected, especially for the very bright 100-watt bulbs. Part of the problem is that these new bulbs have to fit into lamps and ceiling fixtures designed for older technology.

The big problem with LEDs is that although they don't produce as much heat as incandescent bulbs, the heat they do create shortens the lifespan and reduces the efficiency of the chips. Cramming a dozen chips together in a tight bulb-shaped package that fits in today's lamps and sockets makes the heat problem worse. The brighter the bulb, the bigger the problem is.

However, LED prices are coming down quickly. The DoE expects a 60-watt equivalent LED bulb to cost $10 by 2015, putting them within striking range of the price of a compact fluorescent bulb.

And from CNET

Philips switches on bright LED bulb
CNET, May 16

The EnduraLED A21 will be the first general-purpose LED bulb to give off as much light as a 75-watt incandescent bulb, according to Philips. It will be rated at 1,100 lumens and an efficiency of almost 65 lumens per watt.

The bulb will have a rated life of 25,000 hours, or about 17 years with four hours of daily use. The color rendering index, a measure of light quality, is 80 and the color temperature is 2,700, or a warmer yellow light meant to be similar to incandescents.

There are about 90 million 75-watt incandescent bulbs sold every year in the U.S., and switching to LEDs would eliminate the carbon emissions of almost 1 million cars, according to Philips.

Budget LEDs debut on Amazon
CNET, April 22

I suspect the people who now complain about the amount of Hg enclosed in a CFL might be the same people who oppose banning mercury thermometers - and most people don't put a CFL in their mouth OR elsewhere!