New Lighting Tips for the 21st Century look

Lots of Heat and a little light

We have been supplementing daylight with artificial light for several thousand years. First there was primitive man who found that burning wood produced flames which brought light to their dark caves and then making candles and torches from sticks covered in animal fat so they could spend the night hours fashioning weapons and tools and creating wall art.

With the advent of manuscripts and books came the need for longer burning wax candles to banish the darkness so education and knowledge could flourish. Then, about 200 years technology took another leap forward when coal gas became commercially available for lighting homes and streets at the turn of a knob. Finally, with the arrival of electricity we see the arrival of that triumph of modern engineering, the incandescent filament.

But in reality the modern lightbulb, for all its elegant design and reliable operation at the flick of a switch is not really all that efficient - Why? because it actually produces heat, the light is just a by-product of that heat. So really they should be called heat bulbs, not light bulbs. A standard light bulb emits around 15 lumens per watt of power consumption.

Light without heat.

Now for the first time we can produce light directly from electricity without heating. For the last sixty years fluorescent light tubes have been used, they use electricity to generate ultra-violet light which in turn excites a coating on the glass tube that fluoresces to produce visible light. The new compact variety of fluorescent tubes called CFLs can be used in standard light sockets and are more efficient as they don't product much wasted heat energy so produce about 4 times more light for the same power consumption. A standard CFL emits around 100 lumens per watt of power consumption.

LEDs are more efficient

The latest type of energy efficient lighting is achieved by using an electronic component called a light emitting diode, commonly called an LED. An electric current is passed through the diode causing the diode's atoms to emit light particles which we see as visible light. This effect is almost a reversal of the photoelectric effect which is used to produce electrical current by light stimulation, as used in solar panels. LEDs have been used since the early sixties, but these were not very strong lights, only useful in electronic devices as indicator lights such as the LED lights used to make up the digits in early calculators. But over time technological advances have produced more powerful LED lights, bright enough to replace filament light bulbs. A high brightness LED emits around 200 lumens per watt of power consumption.

But today's LED will never truly be able to replace a standard light bulb, Why? Because LED lights have a narrow beam spread, they don't emit light in all directions like incandescent or CFL lights. But they can be used where a narrow beam is needed, such as torches and spotlights. Some manufacturers are making LED lights composed of multiple LEDs to produce a wider spread of light. The last ten years have seen the development of super bright LED lights and eventually design engineers will overcome the narrow beam problem and we will see LED lights used in standard light fittings. Next time we will discuss outdoor lighting using new generation solar lights.