| Popis: |
Simple relationships exist between the aperture of a solar furnace, the target size, the angle of convergence, the maximum attainable concentration ratio, the over-all efficiency, and the amount of spill light surrounding the target. For optical systems having continuous unobstructed surfaces and no spherical aberration, the concentration ratio is determined solely by the angle of convergence. Various systems differ considerably, however, in the amount by which their apertures exceed that of an ideal system of equal performance; in the resulting efficiency at which they operate; in the associated amount of waste light spilled outside the target; in the distribution of this spill light; and in the relative convenience with which they can be fabricated and adjusted. A paraboloidal mirror with heliostat does not seem to be an optimum choice. The optical possibilities afforded by other two-mirror systems are discussed and illustrated by example. We also present structural design for a two-mirror system which appears to possess some practical advantages over the heliostat-paraboloid combination. |
