Rankine cycle system and method

Abstract

A Rankine cycle system and method is described and illustrated, and in some embodiments includes an expander, a pump, a condenser, and a receiver comprising a variable fluid volume at least partially defined by a movable member, wherein the variable fluid volume defines at least a portion of the working fluid flow path between the condenser and the inlet of the pump. Also, a method of charging a Rankine cycle system with working fluid is described and illustrated, and can include applying a regulated pressure to a chamber located within a receiver, introducing the working fluid to the Rankine cycle system, the working fluid being separated from the chamber by a movable member of the receiver, monitoring displacement of the movable member, and stopping the introduction of working fluid into the Rankine cycle system when the movable member reaches a predetermined position.

What is claimed is: 
     
         1 . A Rankine cycle system comprising:
 an expander;   a pump;   a condenser located along a working fluid flow path between an outlet of the expander and an inlet of the pump; and   a receiver comprising a variable fluid volume at least partially defined by a movable member, wherein the variable fluid volume defines at least a portion of the working fluid flow path between the condenser and the inlet of the pump.   
     
     
         2 . The system of  claim 1 , further comprising a liquid sub-cooler located along the working fluid flow path between the receiver and the inlet of the pump. 
     
     
         3 . The system of  claim 2 , wherein the condenser and the liquid sub-cooler are parts of a single heat exchanger. 
     
     
         4 . The system of  claim 1 , wherein at least a portion of the variable fluid volume defines a cylindrical volume, the movable member defining an end of the cylindrical volume. 
     
     
         5 . The system of  claim 4 , wherein the movable member is movably disposed within the receiver so as to vary the length of the cylindrical volume. 
     
     
         6 . The system of  claim 1 , wherein the variable fluid volume is a first variable fluid volume, the receiver further comprising a second variable fluid volume at least partially defined by the movable member. 
     
     
         7 . The system of  claim 6 , wherein the second variable fluid volume is in fluid communication with the environment outside of the receiver to maintain a substantially atmospheric pressure within the second variable fluid volume. 
     
     
         8 . The system of  claim 6 , wherein the second variable fluid volume is in fluid communication with a regulated pressure source. 
     
     
         9 . The system of  claim 1 , wherein the movable member is positioned within the receiver, and wherein the receiver includes a position indicator to indicate the location of the movable member within the receiver. 
     
     
         10 . The system of  claim 9 , wherein the position indicator is magnetically coupled to the movable member. 
     
     
         11 . The system of  claim 1 , wherein the variable fluid volume is further defined by an end face of the receiver, the end face including first and second ports in fluid communication with the variable fluid volume and defining portions of the working fluid flow path immediately upstream and downstream of the variable fluid volume. 
     
     
         12 . The system of  claim 11 , wherein at least one of the end face and the movable member includes an offset surface so that a fluid flowpath is maintained between the first and second ports when the offset surface is in contact with the other of the end face and the movable member. 
     
     
         13 . A method of charging a Rankine cycle system with working fluid, comprising:
 applying a regulated pressure to a chamber located within a receiver in the Rankine cycle system;   introducing the working fluid to the Rankine cycle system, the working fluid being separated from the chamber by a movable member of the receiver;   monitoring displacement of the movable member; and   stopping the introduction of working fluid into the Rankine cycle system when the movable member reaches a predetermined position.   
     
     
         14 . The method of  claim 13 , wherein the regulated pressure is greater than a saturation pressure corresponding to a temperature of the working fluid. 
     
     
         15 . The method of  claim 13 , wherein monitoring the displacement of the movable member includes at least one of visual observation of the movable member and electronic measurement of the movable member. 
     
     
         16 . The method of  claim 13 , wherein monitoring the displacement of the movable member includes monitoring the displacement of a position indicator magnetically coupled to the movable member. 
     
     
         17 . A method of pressure adjustment within a Rankine cycle system having an expander and a pump, the method comprising:
 changing a pressure of working fluid within the system between the expander and the pump;   changing a volume of an internal chamber of a receiver in fluid communication between the expander and the pump responsive to changing the pressure of the working fluid within the system.   
     
     
         18 . The method of  claim 17 , wherein changing the volume of the internal chamber comprises moving a portion of the receiver. 
     
     
         19 . The method of  claim 17 , further comprising receiving the working fluid into the receiver from a first heat exchanger portion, and discharging the working fluid from the receiver to a second heat exchanger portion. 
     
     
         20 . The method of  claim 17 , further comprising changing a volume of a second internal chamber in the receiver responsive to changing the pressure of the working fluid within the system.