Solar energy can be made use of in different ways. We have solar water heaters, solar cookers, solar photovoltaic cells, and other ‘solar’ this and that. Solar water heaters and solar cookers may use concave parabolic reflectors to concentrate the heat rays of the sun onto a particular spot, and use the intense heat generated to provide hot water. Have you ever heard of solar engines with curved mirrors?
Well, here is an innovation that makes use of solar energy very effectively. Touted to be the most power efficient solar energy distiller, the SunCatcher is a sunlight collector that concentrates the heat rays over a Power Conversion Unit (PCU). It generally comprises a radial dish that acts as the collector. There is an array of curved mirror facets that continuously track the sun. The concave mirrors reflect the light rays from sun (infinity) to their focus point. There is a boom that supports the Power Conversion Unit at the mirror’s focus, and the whole setup is supported on a facet support structure with a movable pedestal.
The Power Conversion Unit is quite similar to an Internal Combustion Engine. In an IC Engine, the burnt fuel supplies heat energy to the air inside the cylinder. This heat causes a pressure which in turn moves the piston. Here, in a PCU, the heat source is the giant SunCatcher and a four-cylinder system is used. The solar receiver tubes of the PCU are filled with hydrogen gas. The PCU is directly heated by the intense sun rays and this heat causes an expansion of hydrogen, and the pressure owing to the expansion moves the piston back and forth and powers the engine.
This power is purely mechanical. To convert this into electrical energy, a dynamo or an alternator is coupled to the shaft of the solar engine. The PCU functions as a heat exchanger. The cooling process is simpler than that of an IC engine. The gas is recycled and used again.
This is an amazing invention and has great potential. The capacity of a normal SunCatcher is about 25kWe (kilowatt-electrical).