Abstract: A central solar receiver comprising a tubular housing with a central axis, a radiation admitting aperture and an absorber chamber having an outer wall, two oppositely located ends, an inner-wall-forming substantially tubular transparent window co-axial with the tubular housing. The solar receiver further comprises injection means near a first of the oppositely located ends and at least one egress opening means near a second of the oppositely located ends. The injection means are capable of injecting into the absorber chamber a multicomponent fluid mixture comprising at least one radiation absorbing component and are so designed that the fluid mixture is injected into the absorber chamber adjacent and essentially tangentially to the outer wall, whereby contact between the mixture and the window is reduced. The egress opening enables the egress of the fluid mixture from the absorber chamber.

Abstract: A central solar receiver comprising a housing with a frusto-conical window for the admission of incident concentrated solar radiation, a volumetric solar absorber within the housing surrounding the window, means for the injection of working fluid into contact with the volumetric solar absorber and means for the withdrawal of heated working fluid. The frusto-conical window makes the receiver suitable for operation at elevated pressure.

Abstract: A central solar receiver comprising a housing with a window for the admission of incident concentrated solar radiation, a volumetric solar absorber within the housing comprising a base body holding an array of absorber members spaced from each other and projecting from one face thereof with their free ends facing said window, means for the injection of working fluid into the volumetric solar absorber in flow directions which intersect the absorber members and means for the withdrawal of heated working fluid. The window of the central solar receiver is a tubular frusto-conical body coaxial with the housing, whereby the receiver is adapted for operation at elevated pressure.