Rankine cycle

Abstract

A Rankine cycle where, in a circulation path of a working fluid, a heat exchanger exchanging heat between the working fluid and a heat medium, an expander, a condensing unit and a pumping device are provided in order, includes a temperature detector detecting the temperature of the working fluid flowing out of the heat exchanger, a pressure detector detecting the pressure of the working fluid flowing through the heat exchanger, a flow rate adjusting unit for adjusting the working fluid flow rate to the heat exchanger and a control device controlling the adjusting unit. The control device controls to change the temperature and pressure of the working fluid sucked into the expander while satisfying the relationship along the target pressure line TPL where the target pressure is set to increase the working fluid density following the increase in the working fluid temperature.

1 - 6 . (canceled) 
     
     
         7 . A Rankine cycle where, in a circulation path of a working fluid, a heat exchanger that implements heat exchange between the working fluid and a heat medium, a fluid expander that generates driving power by expanding the working fluid, a condensing unit that condenses the working fluid and a fluid pumping device that transfers the working fluid to the heat exchanger are provided in order, wherein a state of the working fluid after the heat exchange with the heat medium in the heat exchanger is superheated vapor, the Rankine cycle comprising:
 a temperature detector that detects a temperature of the working fluid flowing out of the heat exchanger;   a pressure detector that detects a pressure of the working fluid flowing through the heat exchanger;   flow rate adjusting means for adjusting a flow rate of the working fluid into the heat exchanger; and   a control device that controls the flow rate adjusting means,   wherein the control device sets a target pressure such that a density of the working fluid flowing out of the heat exchanger increases following an increase in the temperature detected by the temperature detector, and controls the flow rate adjusting means so that the detected pressure of the pressure detector becomes the target pressure, and   wherein, following the increase in the temperature detected by the temperature detector, the control device controls the flow rate adjusting means to increase the flow rate of the working fluid into the heat exchanger.   
     
     
         8 . The Rankine cycle according to  claim 7 , wherein an upper limit pressure is set for the target pressure, and when the temperature detected by the temperature detector is equal to or higher than a predetermined temperature, the flow rate adjusting means is controlled so that the detected pressure of the pressure detector becomes the upper limit pressure. 
     
     
         9 . The Rankine cycle according to  claim 7 , wherein the target pressure is proportional to an enthalpy of the working fluid flowing out of the heat exchanger. 
     
     
         10 . The Rankine cycle according to  claim 7 , wherein
 the flow rate adjusting means comprises:   a bypass communicating the flow path of the working fluid, which extends from the fluid pumping device towards the heat exchanger, with the flow path of the working fluid, which extends from the fluid expander towards the fluid pumping device; and   a flow rate regulating valve capable of adjusting the flow rate of the working fluid in the bypass.   
     
     
         11 . The Rankine cycle according to  claim 10 , wherein the bypass is connected between the condensing unit and the fluid pumping device on the flow path of the working fluid extending from the fluid expander towards the fluid pumping device.