A cone concentrator for high-temperature solar cavity-receivers

A cone concentrator combined with a solar cavity receiver is presented and its performance compared to a single cavity receiver. For both cases the av ailable heat sink within the receiver is calculated. The cone concentrator suffers from a high amount of rejected rays if the exit aperture is made to o small. A larger exit aperture on the other hand increases the thermal los ses of the cavity. The optimum cone geometry therefore has to be found taki ng also into account a model of the cavity. Different operating temperature s and different values of absorption coefficients of the cavity walls are c onsidered. A cone concentrator was built and tested at the solar furnace in Cologne. It transmits 97 percent of the rays entering the entrance apertur e, which is in exact agreement with the theoretical predictions. (C) 1998 E lsevier Science Ltd. All rights reserved.