Abstract: A process and system are provided for economic utilization of solar energy. Solar energy is absorbed and converted to thermal energy by means of at least two systems, operating in different temperature ranges, for circulating a primary fluid heat transfer medium through separate collector sections of a solar receiver to recover solar heat and through separate output heat exchangers to supply heat to a second heat transfer medium functioning as a working medium, with heat storage means being associated with each system for the purpose of satisfying the heat requirements of the working fluid and also to prevent cooling down of the collector during the time that little or no solar radiation is available.