(US5323764-A)      The solar receiver includes a housing with a window for the admission of incident concentrated solar radiation. A volumetric solar absorber within the housing, includes a base body holding an array of absorber members spaced from each other and projecting from one face with their free ends facing the window.    Working fluid is injected into the volumetric solar absorber in flow directions which intersect the absorber members. The heated working fluid is then withdrawn. The window of the central solar receiver is a tubular frusto-conical body coaxial with the housing, where the receiver is adapted for operation at elevated pressure.    ADVANTAGE -   Window is well suited to withstand elevated pressure prevailing within receiver.    (US5421322-A)      The central solar receiver is located within a housing fitted with an axi-symmetric, frusto-conical, tubular window. The window has a first, large diameter open end with a first cylindrical rim portion and a second, small diameter open end with a second cylindrical rim portion. The second cylindrical rim portion is connected to the housing by a thermal expansion absorbing bellows.    The window has a double pane. The tubular housing has an opening and a window for admission of incident concentrated solar radiation. A volumetric solar absorber body within the housing has an absorber surface facing the window. The volumetric solar absorber body and said window defining a heating chamber.    ADVANTAGE -   Operates at high pressure. Adapted for housing in central solar receiver.    (RU2048661-C1)      The receiver comprises a tubular frusto-conical window coaxial with a housing admitting concentrated solar radiation to a volumetric solar absorber. The absorber is mounted within the housing and comprises a frusto-conical body holding an array of ceramic spike shaped absorbing members.    At the larger end of the absorber a perforated metal ring allows injection of working fluid from an annular duct. The heated working fluid is withdrawn through an annular chamber with inlets at the smaller end of the absorber, into a tubular vent. The vent is surrounded with an insulating layer which extends to the outer rear portion of the absorber.    ADVANTAGE -   Provides absorber which can operate at elevated pressure. Bul. 32/20.11.95    (JP3058776-B2)      The receiver comprises a tubular frusto-conical window (6) coaxial with a housing (1) admitting concentrated solar radiation to a volumetric solar absorber (30). The absorber is mounted within the housing and comprises a frusto-conical body (31) holding an array of ceramic spike shaped absorbing members (32).    At the larger end of the absorber a perforated metal ring (33) allows injection of working fluid from an annular duct (34). The heated working fluid is withdrawn through an annular chamber (35), with inlets (49) at the smaller end of the absorber, into a tubular vent (36). The vent is surrounded with an insulating layer (37) which extends to the outer rear portion of the absorber.    ADVANTAGE -   Provides an absorber which can operate at elevated pressure.