Friday, May 13, 2011

Let there be light emitting diodes


Because we rely on solar panels for our electricity, we're conscious, though less so each day, about appliances, lights and other gadgets that suck up juice, and curious about new ways to conserve energy. So we were glad to find our local hardware store stocking LED lights that seem almost too good an idea. We had looked at LEDs before but at US$25 apiece we just walked away. Now the price has dropped to about US$7.50 and suddenly they make sense.

How LEDs work I don't know. Internet explanations I checked ranged from moronic ("LEDs are devices that produce light when electricity runs through them." Duh.), to technical jargon that was equally useless. Try this:

Most commercial light-emitting diodes (LEDs), both visible and infrared, are fabricated from III–V semiconductors. These compounds contain elements such as gallium, indium, and aluminum from column III (or group 13) of the periodic table, as well as arsenic, phosphorus, and nitrogen from column V (or group 15) of the periodic table. There are also LED products made of II–VI (or group 12–16) semiconductors, for example ZnSe and related compounds. Taken together, these semiconductors possess the proper band-gap energies to produce radiation at all wavelengths of interest.

Whatever. The ones we bought are not just one light but a series of tiny lights bundled together and which remain cool to the touch despite their brightness. They are wired so they can replace two-prong halogen lights which consume up to 15 times more electricity and get very hot. The ones we bought are 3 (three) watts and put out as much light as 50-watt halogens. LEDs also come in one-watters which we haven't tried.

According to the package these LEDs are supposed to last up to 20,000 hours. They are useful for replacing halogens used as spotlights on pictures or other special areas. We put ours in a couple of niches showcasing Mexican handicrafts, and on an outside fountain (in sealed outdoor sockets and not submerged in the water). From what we can tell they provide an amount of light comparable to the halogens but use only a fraction of the electricity, which combined with their longevity should make them cost-effective. The wattage for the three fountain lights went from 150 to 9.

A couple of shortcomings. Unlike halogens or regular incandescents, LEDs cannot be dimmed. Cristian, the helpful local hardware young man who seems to know everything involving electrons, says manufacturers are beginning to offer dimmable LEDs, but they are not yet available in Mexico. At a hardware store in New York we also saw dimmable fluorescent energy-saving bulbs.

So LEDs are not suitable for creating the type of dimly-lit, romantic ambiance that minimizes the wrinkles on people's faces. Don't toss out those candles yet.

In fact, LEDs tend to emit a harsh, intense light you don't want shining directly on your eyes. Originally the only color was a ultra-white, almost bluish light, but now they come in various colors, include the "warm white" we bought. I also read that one manufacturer has repackaged tiny LEDs inside a container that looks like a conventional light bulb that can be screwed into a regular socket.

I don't know what's caused the sharp drop in the price of LEDs, but a note on the package carries a familiar hint: "HECHO EN CHINA." A local installer of solar electricity systems told us that the price of photovoltaic panels also is dropping sharply, as China barges into the market like an 800-pound panda.

So here's a question for all libertarians, free-market economists, open-trade advocates, warmed-over socialists, members of Canada's Green Party and any others who fall sleep at night fondling big thoughts. Is it a good thing for China to be flooding our market with these cheaper green products that help us save energy and lessen our dependence on polluting oil and coal, spooky nuclear plants and other old-energy sources--even if the Chinese walk away with most of the profits?

Or even more profound still: Is there anything left at the hardware store that isn't made in China?

Please feel free to post your answers, theories and pontifications in the comments box at the end of this blog.

The ironic thing for us right now is that with more daylight every day we are actually generating more electricity than we need. Yesterday our system produced a little more than 17KW, so LEDs don't seem as urgent as if it were cloudy and rainy, which we hope happens soon.

2 comments:

  1. Its really interesting blog. To effectively plan your garden illumination scheme you need to check the garden thoroughly throughout the day and also again through the night. Use most efficient grow light for indoor gardening.

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  2. That is a fascinating idea; never thought of using LEDs to grow seedlings indoors. That would be particularly useful here because it's often difficult to germinate some seeds outdoors because of the drastic changes in temperature (cold at night), winds, dust and dryness. Thanks.

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