System and method for cooling an expander

A Rankine cycle system, comprising:

• an evaporator configured to receive heat from a heat source and circulate a working fluid to remove heat from the heat source;
• an expander in flow communication with the evaporator and configured to expand the working fluid fed from the evaporator;
• a condenser in flow communication with the expander and configured to condense the working fluid fed from the expander;
• a pump in flow communication with the condenser and configured to pump the working fluid fed from the condenser,
• a first conduit for feeding a first portion of the working fluid from the pump to the evaporator;
• and
• a second conduit for feeding a second portion of the working fluid from the pump directly to the expander,
• wherein the second portion of the working fluid is fed to at least one location in the expander, and
• wherein the expander comprises a multi-stage expander and the at least one location comprises at least two locations with a first location comprising a location corresponding to a position of at least one expander component and a second location comprising a location in-between two stages of the multi-stage expander.

A method of operating a Rankine cycle system, comprising

• circulating a working fluid in an evaporator in heat exchange relationship with a heat source so as to vaporize the working fluid;
• expanding the vaporized working fluid in an expander, wherein the expander comprises a multi-stage expander;
• condensing the expanded working fluid via a condenser fed from the expander;
• pumping the condensed working fluid,
• supplying a first portion of the pumped working fluid to the evaporator;
• and
• supplying a second portion of the pumped working fluid directly to at least one location in the expander, wherein the at least one location comprises a location in-between two stages of the multi-stage expander.