Solar power system

In a power system, a method for driving a mechanically driven device using a working fluid whose thermodynamic state traverses a Rankine power cycle, comprising:

• (a) heating and vaporizing a liquid portion of said working fluid:
• (b) expanding said working fluid vapor in a heat engine which drives said mechanically driven device;
• (c) condensing said expanded vapor after leaving said engine and returning said liquid back for further heating and vaporizing;
• and
• (d) controlling the temperature of vaporization of said working fluid by varying the torque presented to said engine by said mechanically driven device.

An improved power system for driving a load mechanically wherein the power system is of the type having a working fluid whose thermodynamic state traverses a Rankine power cycle and one or more working-fluid circuits, within which the working fluid circulates, which include:

• (a) means for absorbing heat from a source of heat and vaporizing liquid working fluid which includes one or more working fluid passages;
• said absorbing and vaporizing means being of the type wherein the rate at which heat is absorbed by the working fluid, in the one or more fluid passages of the absorbing and vaporizing means, depends significantly on the value of the difference between the temperature of vaporization of the working fluid and the equivalent temperature of the surroundings of the absorbing and vaporizing means;
• (b) a heat engine in which the vapor generated in the heat absorbing and vaporizing means is expanded, said heat engine being employed to drive the mechanically-driven load;
• (c) means for condensing said expanded vapor;
• and
• (d) means for pumping said condensed vapor back to the entrance of said absorbing and vaporizing means;
• wherein the improvement comprises means for controlling the temperature of vaporization of the working fluid in the heat absorbing and vaporizing means by varying the load, and in particular the torque, presented to the heat engine by the mechanically-driven load, so as to maximize a performance quantity related to the power delivered by the heat engine under prevailing conditions external to the power system which at the same time supplying dry vapor to the heat engine;
• and wherein the control of said temperature of vaporization by said load, and in particular by said torque, is achieved through changes in rotational speed of the heat engine and in associated changes in mass flow rate of the working fluid.