Tag Archives: light

Cold Incandescent Light Bulbs?

Just when you thought incandescent bulbs were going out, they’ve been “reinvented” to be even more efficient than LEDs!

Normally Incandescent bulbs are about 5-10% efficient as most of the energy is converted to wasted heat and this age-old problem has finally been solved.

We’re literally talking about recycling light in a two step process.

The key is to create a two-stage process, the researchers report. The first stage involves a conventional heated metal filament, with all its attendant losses. But instead of allowing the waste heat to dissipate in the form of infrared radiation, secondary structures surrounding the filament capture this radiation and reflect it back to the filament to be re-absorbed and re-emitted as visible light. These structures, a form of photonic crystal, are made of Earth-abundant elements and can be made using conventional material-deposition technology.

That second step makes a dramatic difference in how efficiently the system converts electricity into light. One quantity that characterizes a lighting source is the so-called luminous efficiency, which takes into account the response of the human eye. Whereas the luminous efficiency of conventional incandescent lights is between 2 and 3 percent, that of fluorescents (including CFLs) is between 7 and 15 percent, and that of most commercial LEDs between 5 and 20 percent, the new two-stage incandescents could reach efficiencies as high as 40 percent, the team says.

The first proof-of-concept units made by the team do not yet reach that level, achieving about 6.6 percent efficiency. But even that preliminary result matches the efficiency of some of today’s CFLs and LEDs, they point out. And it is already a threefold improvement over the efficiency of today’s incandescents.

The team refers to their approach as “light recycling,” says Ilic, since their material takes in the unwanted, useless wavelengths of energy and converts them into the visible light wavelengths that are desired. “It recycles the energy that would otherwise be wasted,” says Soljačić.

The rest of the article available here: http://news.mit.edu/2016/nanophotonic-incandescent-light-bulbs-0111 mentions that the crystal is created with readily available natural ingredients so cost will probably not be an issue if they actually get these out to the public.

Solar Lamp Only $2

Solar Lamp

In some third world countries, when the sun goes down, there is no light for the people. If there is, it is usually a kerosine lamp that burn indoors. The light is useful, but some claim that one night of breathing in the fumes is the same as smoking 40 cigarettes. And to top it off, 20% of a family’s income every week pays for the fuel.

$2 Solar Lamp by LEDsafari
$2 Solar Lamp by LEDsafari

The folks at LEDsafari are doing some great work using a very simple method. They use a cell phone battery with the electronics removed, an LED, a switch and a small solar cell to build a low cost solar lamp.

Little by little their method is getting a bit more sophisticated. LEDsafari is now adding a diode to keep the battery from sending power to the solar cell and burning it up. Also, a resistor is added to limit the current the battery delivers to the LED so it lasts longer. Total cost is about $2.00.

There are some simple ways to improve upon these methods. But for now, this project has been a blessing for thousands of people. Without LEDsafari’s solar lamp program, many would be sitting in the dark or spending money just to breath unhealthy fumes. This just shows that something so small and simple really can make a huge difference in people’s lives!

LEDsafari Students
LEDsafari Students

Saving Money, Reducing Fuel & Increasing Health

The income savings and health benefits are obviously priceless. It is important to understand this isn’t a hand-out. LEDsafari holds workshops to teach people how to empower themselves by learning how to build their own solar lamp! Just look how happy those kids are in the picture up above. This is not just a technical skill, but a way to increase their self-esteem and build confidence in the fact that they can help themselves.

Support this project by telling your friends, sharing this page and visiting: LEDsafari