Manila Bulletin

LED lighting

- By FR. EMETERIO BARCELON, SJ

THE efficiency ratio between LED and incandesce­nt lighting is about 20 times; so that a 3-watt LED is equivalent to a 60-watt bulb of the incandesce­nt lamp. They are also sturdier and can take a lot of beating. They can last 10 to 15 years as against the life time of two years for the incandesce­nt lamp. The cost is about six times more. The 3-watt LED is sold at about 120 at present while the incandesce­nt 60-watt bulb is about 20.

The government could provide an incentive to use the LED but here is the problem in this country our financing system is in its infant stage. We have no financing for such a sure project as this. This is where we are being left behind by our neighbors. Surprising, that Kuala Lumpur and Singapore have left us behind in finance. It would not have been surprising if it was Shanghai or Hong Kong that left us behind since there have been hundreds of years of financing and insurance coverage on the Yangtze and other big rivers of China.

LED is light emitted from a solid diode of chemicals in the III and V columns of the periodic table; for example, gallium arsenide. The red light from solids was discovered some time ago but it was a Japanese group (Akasaki, Amano, and Nakamura) that were able to produce the blue light and accordingl­y the whole spectrum to produce white light. They were awarded the Nobel Prize for science. The technology is a bit complicate­d but is now being produced in large quantities both in the US and China. For lighting, therefore, there is no reason to keep people in darkness. In combinatio­n with solar source of power, we should be able to give adequate light for study and entertainm­ent to most of our people.

In a University, where I am, and in laboratori­es, department stores, and many other places, the need for power is heavy during day time. This obviates the use of batteries. And within 30 degrees north and south of the equator the source of solar light has been studied rather extensivel­y as sufficient for most purposes without use of batteries. The Philippine­s lies 5” to 15” north of the equator. Inorganic photovolta­ic solar cells are becoming cheaper every day. At present they can produce one watt cheaper than any other source such as coal and hydro. The only problem is that they are available only six hours a day and therefore need batteries for use during non-sunlight hours.

At present the heat of the sun could be used for thermal heating of water and from there produce electricit­y. There are some plants in the world as in Nebraska where thermal rather than photo voltaic is used. The solar radiation is concentrat­ed through reflectors and prisms to boil water and this produces the power. But the prospectiv­e for solar energy is really with the (PV) or photovolta­ic. At present there are three systems in use one of which is silicon system but new or other arrangemen­ts can be found to harness the rays of the sun. They are used to dislodge electron.

Light-induced voltage was discovered in 1839 by Becquerel. In 1883 C. Fritts demonstrat­ed the first solar cell. But it was only in 1946 that the modern solar cells was patented and developed by the scientists in Bell laboratori­es in 1954. Plenty of work is being done on these solar cells at present so that its price is expected to drop a lot more.

***

Unfortunat­e that Grace Poe decided to run for president at this time. She ruined what would have been a sure thing next time. In the opinion of many, she is not yet tough enough to suffer the pressures the president undergoes. But that is an opinion. Now a fearless forecast is that Duterte will also throw his hat into the fray. The best chances will still be for Mar Roxas and Duterte. At least Mindanaoan­s will now have a chance to vote for someone who knows the problems of Mindanao. <emeterio_barcelonya­hoo.com>

 ??  ??

Newspapers in English

Newspapers from Philippines