Solar-radiation receiving apparatus for heating a heat-transfer medium, formed by particles, in a solar thermal power station, comprising - a container which has two oppositely situated ends (202, 204) and comprises an outer wall and an interior space surrounded by the outer wall; - a feed device for feeding the heat-transfer medium to the interior space of the container, wherein the feed device is arranged at one of the ends (202, 204) of the container; - a discharge device for discharging the heat-transfer medium from the container, wherein the discharge device is arranged at the same or oppositely situated end (202, 204) of the container; and - an aperture opening for the entry of solar radiation at one of the ends (202, 204); wherein the container has a longitudinal axis, which is oriented parallel or at an angle less than 90° to the direction of gravitational force (g), wherein the container can be rotated in an intended direction of rotation by means of a rotary-drive apparatus of the solar-radiation receiving apparatus about an axis of rotation in such a way that the heat-transfer medium can be carried along on an inner wall of the container resulting in the formation of a film of heat-transfer medium, wherein the inner wall of the container has a friction-promoting device, wherein the feed device has a front wall with a feed opening and a back wall directed towards the interior space of the container, wherein the discharge device at the discharge-side end of the container has at least one device which selectively limits a loss of heated particles of the heat-transfer medium from the discharge device, characterized in that the device has at least one baffle element which protrudes in a radial direction, is arranged at the discharge-side end of the outer wall of the container at the transition to a static collecting ring of the discharge device, and is curved along its extent between the inner wall and the outer wall in the direction of the intended direction of rotation, wherein the at least one baffle element deflects the particles and accelerates them in the rotating reference system such that they have a considerably lower speed in the vertical reference system, or wherein the device has a collecting device, which leads away in the radial direction outwards, in particular helically, from the outer wall at the discharge-side end of the container, wherein the collecting device is fixedly connected to a receiving device arranged outside the container, and wherein the collecting device has an inlet opening, which is aligned counter to the intended direction of rotation of the container and is designed to discharge the heated heat-transfer medium. - a container which has two oppositely situated ends (202, 204) and comprises an outer wall and an interior space surrounded by the outer wall; - a feed device for feeding the heat-transfer medium to the interior space of the container, wherein the feed device is arranged at one of the ends (202, 204) of the container; - a discharge device for discharging the heat-transfer medium from the container, wherein the discharge device is arranged at the same or oppositely situated end (202, 204) of the container; and - an aperture opening for the entry of solar radiation at one of the ends (202, 204); wherein the container has a longitudinal axis, which is oriented parallel or at an angle less than 90° to the direction of gravitational force (g), wherein the container can be rotated in an intended direction of rotation by means of a rotary-drive apparatus of the solar-radiation receiving apparatus about an axis of rotation in such a way that the heat-transfer medium can be carried along on an inner wall of the container resulting in the formation of a film of heat-transfer medium, wherein the inner wall of the container has a friction-promoting device, wherein the feed device has a front wall with a feed opening and a back wall directed towards the interior space of the container, wherein the discharge device at the discharge-side end of the container has at least one device which selectively limits a loss of heated particles of the heat-transfer medium from the discharge device, characterized in that the device has at least one baffle element which protrudes in a radial direction, is arranged at the discharge-side end of the outer wall of the container at the transition to a static collecting ring of the discharge device, and is curved along its extent between the inner wall and the outer wall in the direction of the intended direction of rotation, wherein the at least one baffle element deflects the particles and accelerates them in the rotating reference system such that they have a considerably lower speed in the vertical reference system, or wherein the device has a collecting device, which leads away in the radial direction outwards, in particular helically, from the outer wall at the discharge-side end of the container, wherein the collecting device is fixedly connected to a receiving device arranged outside the container, and wherein the collecting device has an inlet opening, which is aligned counter to the intended direction of rotation of the container and is designed to discharge the heated heat-transfer medium.