SLL Young Lighter 2020
'School pupils are particularly affected since one in every three primary school students goes to a school without any type of electricity' household income. This expense leads parents to cut down students' study time. Light output from the kerosene lamps is also dull and flickers, which reduces the concentration and energy level of the student, hence the need for high-quality light sources.
THE BENEFITS OF LEDS LED lighting has replaced a lot of kerosene lamps on the continent. As they have elsewhere in the world, LEDs have become a great competitor of conventional lighting technologies. The LED is a semiconductor based on the p-n junction of a diode that emits visible light of a certain colour when electricity passes through it. It has a long life, from 25,000 to 50,000 hours, and also a high luminous efficacy which ranges from 60-130 lm/W. It is therefore very useful in batterypowered systems, and continuously improving. Their efficiency reduces the operational cost compared to other light sources, and they produce higher luminous flux in smaller packages which is favourable in most lighting applications. There has also been a price drop in the LED industry, making it affordable to the rural population.
March/April 2021
poor capacitor construction, inefficient heatsink design and use of poor-quality components. Driver failure contributes to 60 per cent of LED luminaire failure. Africa still lacks the infrastructure to manage electronic waste and this poses a challenge for ensuring proper collection and recycling. With the sharp rise in the production of batterypowered consumer electronics the continent is seeing more batteries finding their way to dumpsites before the end of their lifespan. These batteries can be reused to power LED chips from luminaires that have been disposed of, a proposition made more viable by the high efficacy of LED lighting.
OFF-GRID POWER The high solar yields that are received in Africa generally makes off-grid solar lighting a highly practical solution for improving lighting in schools. Furthermore, the decrease in solar equipment prices also means there is increased potential for joint ventures between the government, NGOs and the general population to ensure that the schools get reliable lighting solutions. DC solar systems would be used to power LED chips directly, to increase efficiency and eliminate the use of sophisticated drivers which, as mentioned before, shorten the lifespan of the chip. DC solar systems in LED lighting have the following benefits compared to an AC solar system:
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better for charging batteries more efficient if most energy needs to be stored, meaning longer lighting hours easy to set up and safe to work with for voltages below 48V eliminates the use of inverters which reduces the overall system cost by 20 per cent
This system would be set up at schools and other central points so as to cater for students living far away from the school and ensure reliable access to lighting. The off-grid solar lighting set up would consist of DC LED luminaires, solar panels, charge controllers, batteries, and charging ports (5V and 12V) for charging individual lanterns. The system would be sized to provide power for charging the batteries and the individual lanterns. The lumen method and Dialux Evo would be used to ensure 300 lux general lighting for classrooms is achieved. Students and teachers would be taught the basics of setting up and maintaining the off-grid solar lighting system. Multiple USB charging ports would be provided for charging individual lanterns. The process would also involve establishing collection points and sorting areas for electronic waste, typically from LED sources, rechargeable torches, power banks and cellphone batteries. Students, teachers and the community would be trained on how to reuse the abovementioned e-waste to make lanterns.
Kerosene lamps have become a widely used light source at the expense of both health and the environment
RECYCLED COMPONENTS The concept uses off-the-shelf DC converters and chargers. LEDs are designed for lowvoltage DC which makes drivers a requirement for using them in AC systems. The drivers usually fail before the LED chip fails and this is due to
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