Solar mirror

A Solar Mirror is a viable means to collect fairly dispersed solar radiation and re-direct it to a point of ultimate use. A fair amount of investigation has gone into the concept for two reasons.

First

Solar radiation at the surface of the earth is fairly difuse, containing only about 1 kw of energy per sq. meter of area normal to the direction of the sun. To use this energy for anything from cooking to powering a turbine-electrical generator, this energy must be concentrated, a task normally assigned to flat or parabolic arrays of solar mirrors.

Second

Photovoltaic cells which can convert solar radiation directly into electricity are quite expensive per unit area, and, if cooled, are capable of converting efficiently up to 250 times as much radiation as in normally provided by simple exposure to direct sunlight. In tests done by ({Web reference 1| author=Sewang Yoon, Vahan Garboushian title=Reduced Temperature Dependence of High-Concentration Photovoltaic Solar Ccell Open-Circuit Voltage (Voc) at High Concentration Levels URL=http://www.amonix.com/Tech_Papers/Temp_Depend.htm year=2005 date=Jan 3) [1] for Amonix Corp., the authors state that photocell percent conversion efficiency actually increases at higher levels of concentration, often by significant amounts, provided external cooling is provided to the photocells. For this reason, particularly for Space Solar Power designs now being considered, Solar Mirrors can reduce photocell costs and launch costs since they are expected to be both lighter and cheaper than equivalent large areas of photocells.

Summary

A good overview of options possible for space-based solar power systems is this study supported by Boeing corporation available at [2] {{Web reference 2| author=Seth D. Potter, Harvey J. Willenberg, Mark W. Henley, and Steven R. Kent title=Architecture Options for Space Solar Power URL=http://www.ssi.org/Potter_SSP_99_SSI.pdf year=2005 date=Jan 3} In Fig. 4. captioned Architecture 4. GEO Harris Wheel, the authors describe a system of solar mirrors used to augment the power of some nearby solar collectors, from which the power is then transmitted to receiver stations on earth.

At [3] {{Web reference 3| author=Len Gould title=Tension Stabilized Steerable Orbiting Mirror URL=http://www.ecologen.com/page_TSSOM2-75.html year=2005 date=Jan 3} is described one interesting method to construct such an orbiting mirror.