Heat exchanger, heat engine system and control method using the same

Abstract

A heat exchanger is provided. The heat exchanger comprises an evaporator, a vapor-liquid separator, a liquid level sensor and a controller. The evaporator is used for heating a working fluid up to a vapor-liquid state, and has a working fluid inlet pipe and a working fluid outlet pipe. The vapor-liquid separator is connected to the working fluid outlet pipe for separating the working fluid into a vapor working fluid and a liquid working fluid. The liquid level sensor detects a level of the liquid working fluid inside the vapor-liquid separator and outputs a liquid level signal. The controller receives the liquid level signal and controls the vapor quality of the working fluid inside the evaporator.

What is claimed is: 
     
         1 . A heat exchanger, comprising:
 an evaporator for heating a working fluid up to a vapor-liquid state, wherein the evaporator has a working fluid inlet pipe and a working fluid outlet pipe;   a vapor-liquid separator connected to the working fluid outlet pipe for separating the working fluid into a vapor working fluid and a liquid working fluid;   a liquid level sensor for detecting a level of the liquid working fluid inside the vapor-liquid separator and outputting a liquid level signal; and   a controller for receiving the liquid level signal to control a vapor quality of the working fluid inside the evaporator.   
     
     
         2 . The heat exchanger according to  claim 1 , wherein the vapor quality of the working fluid inside the evaporator is between 0.6-0.8. 
     
     
         3 . The heat exchanger according to  claim 1 , wherein the level of the liquid working fluid inside the vapor-liquid separator is inversely proportional to the vapor quality of the working fluid inside the evaporator. 
     
     
         4 . The heat exchanger according to  claim 1 , wherein the controller determines whether the vapor quality of the working fluid inside the evaporator is greater than a predetermined value to obtain a state of the working fluid, the predetermined value is settled when a vaporization ratio of the working fluid is greater than 0.8. 
     
     
         5 . The heat exchanger according to  claim 4 , wherein when the vapor quality of the working fluid is greater than the predetermined value, the controller adjusts the flow velocity of the working fluid to increase a flow rate of the working fluid at an inlet of the evaporator. 
     
     
         6 . The heat exchanger according to  claim 1 , wherein the vapor-liquid separator has a vapor working fluid outlet pipe and a liquid working fluid reflow pipe, the liquid working fluid reflow pipe is connected to the working fluid inlet pipe of the evaporator for reflowing the liquid working fluid into the evaporator. 
     
     
         7 . A heat engine cycling system, comprising:
 an evaporator for heating a working fluid up to a vapor-liquid state, wherein the evaporator has a working fluid inlet pipe and a working fluid outlet pipe;   a vapor-liquid separator connected to the working fluid outlet pipe for separating the working fluid into a vapor working fluid and a liquid working fluid, wherein the vapor-liquid separator has a vapor working fluid outlet pipe and a liquid working fluid reflow pipe, the liquid working fluid reflow pipe is connected to the working fluid inlet pipe for reflowing the liquid working fluid into the evaporator;   a liquid level sensor for detecting a level of the liquid working fluid and outputting a liquid level signal;   a controller for receiving the liquid level signal and controlling a vapor quality of the working fluid inside the evaporator;   a condenser for cooling the working fluid to a liquid state;   a power generation module connected to an outlet of the vapor-liquid separator through a first pipe and connected to an inlet of the condenser through a second pipe; and   a pump connected to an outlet of the condenser through a third pipe and connected to an inlet of the evaporator through a fourth pipe.   
     
     
         8 . The heat engine cycling system according to  claim 7 , wherein the vapor quality of the working fluid inside the evaporator is between 0.6-0.8. 
     
     
         9 . The heat engine cycling system according to  claim 7 , wherein the level of the liquid working fluid inside the vapor-liquid separator is inversely proportional to the vapor quality of the working fluid inside the evaporator. 
     
     
         10 . The heat engine cycling system according to  claim 7 , wherein the controller determines whether the vapor quality of the working fluid inside the evaporator is greater than a predetermined value to obtain a state of the working fluid, and the predetermined value is settled when a vaporization ratio of the working fluid is greater than 0.8. 
     
     
         11 . The heat engine cycling system according to  claim 10 , wherein when the vapor quality of the working fluid is greater than the predetermined value, the controller adjusts the flow velocity of the working fluid to increase the flow of the working fluid at the inlet of the evaporator. 
     
     
         12 . The heat engine cycling system according to  claim 7 , wherein the vapor-liquid separator has a vapor working fluid outlet pipe and a liquid working fluid reflow pipe, and the liquid working fluid reflow pipe is connected to the working fluid inlet pipe of the evaporator for reflowing the liquid working fluid into the evaporator. 
     
     
         13 . A control method, comprising:
 providing an evaporator and introducing a working fluid to the evaporator to heat the working fluid up to a vapor-liquid state;   introducing a vapor-liquid working fluid to a vapor-liquid separator for separating the working liquid into a vapor working liquid and a liquid working liquid;   detecting a level of the liquid working fluid and outputting a liquid level signal; and   using a controller to receive the liquid level signal and control a vapor quality of the working fluid inside the evaporator.   
     
     
         14 . The control method according to  claim 13 , wherein the vapor quality of the working fluid inside the evaporator is between 0.6-0.8. 
     
     
         15 . The control method according to  claim 13 , wherein the level of the liquid working fluid inside the vapor-liquid separator is inversely proportional to the vapor quality of the working fluid inside the evaporator. 
     
     
         16 . The control method according to  claim 13 , wherein the controller determines whether the vapor quality of the working fluid inside the evaporator is greater than a predetermined value to confirm whether the working fluid is overheated, and the predetermined value is settled when a vaporization ratio of the working fluid is greater than 0.8. 
     
     
         17 . The control method according to  claim 16 , wherein when the vapor quality of the working fluid is greater than the predetermined value, the controller adjusts the flow velocity of the working fluid to increase a flow rate of the working fluid at an inlet of the evaporator. 
     
     
         18 . The control method according to  claim 13 , further comprising reflowing the liquid working fluid into an inlet of the evaporator.