subject: Solar Concentrators Are The Most Efficient Collectors [print this page] Wikipedia wrote an article on this concept, below is an excerpt from the article.
The parabolic reflector functions due to the geometric properties of the paraboloidal shape: if the angle of incidence to the inner surface of the collector equals the angle of reflection, then any incoming ray that is parallel to the axis of the dish will be reflected to a central point, or "focus". Because many types of energy can be reflected in this way, parabolic reflectors can be used to collect and concentrate energy entering the reflector at a particular angle. Similarly, energy radiating from the "focus" to the dish can be transmitted outward in a beam that is parallel to the axis of the dish.
The trick in making a perfect parabolic concentrator is the shape of the parabolic dish. This is especially important when trying to produce Solar Power, since there cannot be any hotspots that could damage the expensive solar cells. SolarTron Energy Systems is in the process of manufacturing a perfect parabolic concentrator that can produce up to 4kW of electricity, with no hotspots. This solar power system is called SolarBeam.
By using sophisticated imaging software and CAD drawings, the perfect shape has been created, with an efficiency of 80%. Most parabolic shapes that are used for satellites only have an efficiency of around 50%.
The parabolic shape is better than the trough system since it takes up less space and can be placed in harsh climates, because it can tip away snow and ice. Whereas, the trough systems have to be manually cleaned.
The parabolic concentrator can also produce more solar heat than flat panels. 1 SolarBeam concentrator can produce more heat than 12 flat panels, since it can track the sun throughout the day. The SolarBeam can produce 13kW of solar heat; in 2011 the photovoltaic module will produce up to 4kW of electricity.
