Patent ID: 8833079

Claim:
A method of converting solar energy into electricity using atmospheric air as a gaseous working fluid in a Brayton cycle, comprising steps of: directing atmospheric air, to be used as working fluid, to the inlet of a compressor; pressuring said gaseous working fluid in said compressor; heating said high-pressure working fluid in a recuperator using thermal energy in the low-pressure working fluid emerging from a turbine; further heating said high-pressure working fluid in a solar receiver to further increase the temperature and enthalpy of said working fluid; expanding said working fluid by expansion through said turbine, and using the work of said turbine to generate electricity; cooling said low-pressure working fluid emerging from said turbine in said recuperator, which is arranged in counter-flow to said high-pressure working fluid from said compressor; releasing said gaseous working fluid to the atmosphere; wherein the inlet temperature of said turbine is controlled in response to the level of solar energy input, by lowering the temperature and increasing the mass of said high-pressure working fluid entering said solar receiver by introducing an evaporative fluid before said solar receiver to produce evaporative cooling; and adjusting the flow of said evaporative fluid to maximize the power production of said turbine consistent with the level of solar energy received and the maximum allowable turbine inlet temperature.