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Technology Our solar products have been developed to utilise technologies that require no maintenance and incur no enery costs. They use solid-state lighting technology and have a semi-permanent lifespan. Our solar products comprise components including solar cells, LEDs and the EnergyCache, a super ultracapacitor. These are described below. Solid-state Lighting
Lighting applications that use Light Emitting Diodes (LEDs) are commonly referred to as solid-state lighting. Major benefits of solid-state lighting systems include:
Solar Cells (Photovoltaics)
Solar cells convert sunlight directly into electricity. Solar cells are often used to power calculators and watches. Solar cells are made of semiconducting materials similar to those used in computer chips. When sunlight is absorbed by these materials, the solar energy knocks electrons loose from their atoms, allowing the electrons to flow through the material to produce electricity. This process of converting light (photons) to electricity (voltage) is called the photovoltaic (PV) effect.The performance of a PV cell is measured in terms of its efficiency in turning sunlight into electricity. Only sunlight of certain energies will work efficiently to create electricity, and much of it is reflected or absorbed by the material that makes up the cell. Light Emitting Diode (LED)
The LED is a type of diode. Diodes only let current (electricity) flow in one direction. LEDs have the unique "side effect" of producing light while electricity is flowing through them.LEDs are different from ordinary light bulbs because they do not have a filament to break or burn out. They operate on very low voltage from 2-3 volts, generate very little heat, and are ideal for putting lights into portable equipment and self-contained solar lighting devices. In the simplest terms, the LED is made with two different kinds of semiconductor material: one type that has too many free electrons roaming around inside, and another that doesn't have enough. When an electron from one material (the donor) gets pushed across a thin barrier and gets into tiny spaces in the other (the holes), a photon or particle of light is produced. The color of light depends on a number of factors, including the type of material used to make the LED and the material's quantum bandgap (how much energy each electron needs to pack in order to cross the barrier). A smaller bandgap that fairly weak electrons can cross gives you infrared or red light, while a large bandgap that needs really strong electrons gives you light that has a blue or violet color to it. Ultracapacitor
Ultracapacitors are a newly developed technology positioned between the conventional capacitors and rechargeable batteries. Ultracapacitors offer a shift in thought, circumventing the battery scramble, and instead extracts greater efficiency from existing power sources. Ultracapacitors are free from the characteristic battery problems of limited cycle life, cold intolerance and critical charging rates. They are also environmentally friendly, help conserve energy, and enhance the performance and portability of consumer devices.Ultracapacitors can be used to replace batteries in outdoor solar-lighting products. Although their energy capacity is not as great as that of batteries, it is enough to light areas in gardens, driveways, paths and mark roads. In solar lighting, the ultracapacitor has many advantages over batteries.
Ultracapacitors vs. Batteries for Solar Lighting Systems
Rechargeable batteries generate and consume electricity by chemical reaction. This leads to slower responses and the deterioration of performance over time. Usually the charge/discharge cycle is ~1,000 times at best. At this cycle rate, the rechargeable battery has to be replaced every 2-3 years. In addition, the operating temperature range of the rechargeable batteries is very narrow, from 0~45°C (32~113°F). Beyond this range, the performance of the rechargeable batteries drops rapidly. And so the proper working environment of the battery-based solar lighting system is limited. They require maintenance every 2-3 years and have a narrow working temperature range.Ultracapacitors address the drawbacks of rechargeable batteries for solar based lighting systems. Utracapacitors are fast responding and show no deterioration of performance over time. The charge/discharge cycle of the ultracapacitor is more than 100,000 times. This translates into 273 years of continuous operation making it ideal for path lighting and buried traffic lighting. (One cycle of charge and discharge for solar lighting system is one day.) Ultracapacitor vs. Battery for Solar Lighting System
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