Cascading closed loop cycle (CCLC)

Claim 1

A method for converting heat to useful energy based on a Cascading Closed Loop Cycle (CCLC), said method comprising the following steps: A) supplying a primary liquid stream of propane to a primary indirect heat exchanger to vaporize said propane by utilizing the thermal energy derived from a heat source; B) expanding the primary stream of vaporized propane in a primary expansion turbine to produce useful energy; C) leading the primary vaporized propane stream leaving the primary expansion turbine to a secondary indirect heat exchanger; D) superheating a secondary stream of vaporized propane in the secondary indirect heat exchanger; E) expanding the secondary stream of superheated propane in a secondary expansion turbine to produce useful energy; F) leading the primary stream of vaporized propane exiting the secondary indirect heat exchanger to a stream mixer; G) leading the secondary stream of vaporized propane exiting the secondary expansion turbine to the stream mixer; H) combining the primary and secondary streams of vaporized propane in the stream mixer; I) leading the combined stream of vaporized propane to a tertiary indirect heat exchanger for vaporizing the secondary stream of liquid propane; J) leading the combined stream of vaporized propane to a condenser for cooling the same to a liquid; K) leading the combined stream of liquid propane exiting the condenser to a pump; L) pressurizing the combined stream of liquid propane in the pump; M) separating the pressurized combined stream of liquid propane from the discharge of the pump into a primary and secondary propane stream in the stream separator; N) leading the primary stream of pressurized liquid propane to Step A for vaporizing same; and O) leading the secondary stream of pressurized liquid propane to Step I for vaporizing same.

Claim 2

A method for converting heat to useful energy based on a Cascading Closed Loop Cycle (CCLC), said method comprising the following steps: A) supplying a primary liquid stream of propane to a primary indirect heat exchanger to vaporize said propane by utilizing the thermal energy derived from a heat source; B) expanding the primary stream of vaporized propane in a primary expansion turbine to produce useful energy; C) leading the primary vaporized propane stream leaving the primary expansion turbine to a secondary indirect heat exchanger; D) superheating a secondary stream of vaporized propane in the secondary indirect heat exchanger; E) expanding the secondary stream of superheated propane in a secondary expansion turbine to produce useful energy; F) leading the primary stream of vaporized propane exiting the secondary indirect heat exchanger to a stream mixer; G) leading the secondary stream of vaporized propane exiting the secondary expansion turbine to the stream mixer; H) combining the primary and secondary streams of vaporized propane in the stream mixer; I) leading the combined stream of vaporized propane to a tertiary indirect heat exchanger for vaporizing the secondary stream of liquid propane; J) leading the combined stream of vaporized propane to a condenser for cooling the same to a liquid; K) leading the combined stream of liquid propane exiting the condenser to a pump; L) pressurizing the combined stream of liquid propane in the pump; M) separating the pressurized combined stream of liquid propane from the discharge of the pump into a primary and secondary propane stream in the stream separator; N) leading the primary stream of pressurized liquid propane to Step A for vaporizing same; and O) leading the secondary stream of pressurized liquid propane to Step I for vaporizing same.