Manila Bulletin

LED light­ing

- By FR. EMETERIO BARCELON, SJ Renewable Energy · Solar Power · Science · Ecology · Environmental Economics · Business · Kuala Lumpur · Singapore · Shanghai · Hong Kong · Beijing · United States of America · Philippines · Nebraska · Grace Poe · Capiz · Bell Labs

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>

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