Abstract: A concentrated solar energy collection system includes an array of heliostats and a solar receiver that further includes a plurality of tubes having at least one inlet and at least one outlet for carrying a heat transfer fluid (HTF). A flow control arrangement is provided for controlling the flow of HTF through the tubes. This includes at least one radiation sensor such as a pyranometer for sensing values representative of the aggregate solar radiation falling on the solar receiver via the heliostats. At least one temperature sensor measures input temperature of the HTF at or near the inlet. A controller coupled to the radiation and temperature sensors regulates the outlet temperature of the HTF by controlling the flow of HTF through the tubes via the flow control arrangement. A pressure differential sensor arrangement measures pressure differential across the flow control arrangement, providing an input to the controller.