ABSTRACT
This chapter examines radiation utilization at the focus of the solar furnace. Tests have been performed in open air with the 1000kW solar furnace using either direct focal action or rotating-type cavity furnaces. Temperature inside the cavity furnace depends on the power received, the area of the orifice, and the power lost. In addition, the absorption factor of the cavity furnaces for solar radiation is very high and leads to good thermal efficiencies. The horizontal plane is not ‘lighted’ by the entire parabola, but about two-thirds of the heat flux density can be collected on a vertical plane. Because of this limited power and the high reflection values associated with some oxides, the speeds of melting are appreciably less than those obtained in the cavity centrifugal furnaces. In the present state of the art, cavity furnaces do not permit continuous flow, so a technique for melting on a horizontal cooled plate has been developed.
