Comparative performances of 'tower-top' and 'tower-reflector' central solar receivers

The optics of various types of solar tower configurations and receivers are analyzed. The power values that are finally available for the process, for a given field and different optical arrangements at specified operating te mperatures (above 1100 K), are compared, At these temperatures the use of s econdary concentrators placed in front of the receivers is peremptorily jus tified from optical and energetical points of view. A model for calculating the efficiencies of central solar receivers with secondary concentrators i s presented. This model permits the optimization of these secondary concent rators taking into account the different losses of real devices. The effect of heliostat field density and the performance of 'tower-top' and 'tower-r eflector' solar plants are discussed and compared. (C) 1999 Elsevier Scienc e Ltd. All rights reserved.