D. Li (Australia)
521-134 Electricity, Solar cell, Power, and P-V energy system
In standard P-V systems, the world has held back widespread adoption of this technology for decades due to the high cost and low quantum efficiency of silicon cells. Most methods require the concentration of the sunlight in order to increase the efficiency of energy conversion, to generate electrical power from solar energy in a cost effective way. Most systems use parabolic mirrors to focus sunlight to either a line (trough systems) or a small volume (dishes). The high cost of the collection systems, is one of the reasons solar power still remains scarcely utilised. The costs of electricity produced by the action of sunlight on solar cells are still much higher than that produced by the burning of fossil fuels. The most expensive component in a solar cell (also known as a ‘P V cell’) is the silicon material [4]. Although several decades of development have given rise to major increases in efficiency and lower costs, the large areas of silicon required, together with low efficiencies (typically 10 to 15%) have meant that the use of solar cells are only economically viable for certain market segments that do not have access to mains electricity. Light focusing devices using reflection usually take the form of a curved mirror. In paradox, this paper describes the new design of a device consisting of an array of small angled reflecting mirror facets located in a planar form. The 3-D angle of each facet in the array is a function of its position in the array, and is calculated to be such that for a parallel beam striking the array, each facet will reflect the light in such a way as to form a focal point region. Recently, there has been the development of a special type of silicon cell capable of high efficiency operation (up to 25%) at light intensities 10 to 300 times normal sunlight.[5] The use of these cells together with cheaper materials for concentrating sunlight (such as glass / plastic mirrors or lenses) has allowed the development of solar concentrators potentially capable of producing electricity at a lower cost than current flat panels.
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