Patent ID: 7260934

Claim:
An organic Rankine cycle engine comprising: (a) an organic working fluid; (b) a boiler capable of exchanging heat between the working fluid and an external heat source and raising the temperature of the working fluid; (c) a motor, having an intake and an exhaust port, capable of being driven by the working fluid, whereby the working fluid enters the intake port and exits the exhaust port in a gaseous state; (d) a condenser capable of exchanging heat between the working fluid and an external cooling source and lowering the temperature and pressure of the working fluid, whereby the working fluid is liquefied; (e) a first pump capable of transporting the liquid working fluid from the condenser to the boiler, under pressure; and (f) a means to create a pressure differential across the motor, thereby driving the motor, at start-up, selected from the group consisting of: (i) a second pump, positioned between the boiler and the condenser, and a bypass valve and piping for routing the working fluid around the second pump, when the engine is in full operation; and (ii) a reservoir, located between the boiler and the intake port of the motor, capable of isolating a portion of the working fluid from the bulk of working fluid to be heated in the boiler; a check valve located between the reservoir and the boiler, capable of restricting the flow of the working fluid back to the boiler; and a means to selectively increase the pressure of the working fluid in the reservoir, thereby increasing the pressure of the working fluid at the intake port of the motor.