SYSTEM AND METHOD FOR CONTROLLING AN EXPANSION SYSTEM

• US 20090151356A1
• Filed: 12/14/2007
• Published: 06/18/2009
• Est. Priority Date: 12/14/2007
• Status: Active Grant

• Current Assignee: Ai Alpine Us Bidco LLC
• Original Assignee: General Electric Company
• Inventors: Klockow, Helge Burghard Herwig, Bartlett, Michael Adam, Lehar, Matthew Alexander, Ast, Gabor, Frey, Thomas Johannes, Kopecek, Herbert
• Granted Patent: US 8,186,161 B2
• Time in Patent Office: Days
• US Class Current: 60/660
• CPC Class Codes: F01K 13/02 Controlling, e.g. stopping or starting
• CPC Class Codes: F01K 23/101 Regulating means specially adapted therefor F01K23/105, F01K23/108 take precedence
• CPC Class Codes: F01K 25/10 the vapours being cold, e.g. ammonia, carbon dioxide, ether
• CPC Class Codes: Y02P 80/15 On-site combined power, heat or cool generation or distribution, e.g. combined heat and power [CHP] supply

Abstract

A control system includes a temperature sensor communicatively coupled to an exit of an expander of an expansion system and configured to detect temperature of the working fluid flowing through the exit of the expander. A pressure sensor is communicatively coupled to the exit of the expander and configured to detect pressure of the working fluid flowing through the exit of the expander. A controller is configured to receive output signals from the temperature sensor and the pressure sensor and control operation of one or more components of the expansion system so as to control the thermodynamic conditions at the exit of the expander while driving a quality of vapor of the working fluid at the exit of the expander towards a predetermined degree of superheat.

Claims

1. A control system configured to control thermodynamic conditions at an exit of an expander in an expansion system;

the control system comprising;

a temperature sensor communicatively coupled to the exit of the expander and configured to detect temperature of the working fluid flowing through the exit of the expander;

a pressure sensor communicatively coupled to the exit of the expander and configured to detect pressure of the working fluid flowing through the exit of the expander; and

a controller configured to receive output signals from the temperature sensor and the pressure sensor and configured to control operation of one or more components of the expansion system so as to drive a quality of vapor of the working fluid at the exit of the expander towards a predetermined degree of superheat.

2. The control system of claim 1, wherein the predetermined degree of superheat is zero.

3. The control system of claim 1, wherein the controller is configured to maintain a quality of vapor of the working fluid at an inlet of the expander below one.

4. The control system of claim 1, wherein the controller is configured to adjust the thermodynamic conditions at the expander exit of the expansion system based on a plurality of parameters related to the expansion system, wherein the plurality of parameters comprise temperature of working fluid at the exit of the expander, pressure of working fluid at the exit of the expander, type of expansion system;

or a combination thereof.

5. The control system of claim 1, wherein the controller comprises data lookup tables or equations of state;

wherein the controller is configured to calculate vapor quality at the expander exit and at an inlet of the expander based on the output signals from the temperature sensor and the pressure sensor, expander efficiency, equations of state, and/or data lookup tables.

6. A waste heat recovery system, comprising:

a heat source;

a rankine cycle system comprising an expander, wherein the rankine cycle system is coupled to the heat source and configured to circulate a working fluid, wherein the rankine cycle system is configured to remove heat from the heat source; and

a control system coupled to the heat source and the rankine cycle system, the control system comprising;

a temperature sensor communicatively coupled to an exit of the expander and configured to detect temperature of the working fluid flowing through the exit of the expander;

a pressure sensor communicatively coupled to the exit of the expander and configured to detect pressure of the working fluid flowing through the exit of the expander, and

a controller configured to receive output signals from the temperature sensor and the pressure sensor and configured to control thermodynamic conditions at the exit of the expander so as to drive a quality of vapor of the working fluid at the exit of the expander towards a predetermined degree of superheat.

7. The recovery system of claim 6, wherein the predetermined degree of superheat is zero.

8. The recovery system of claim 7, wherein the rankine cycle system further comprises an evaporator coupled to the heat source, wherein the expander is coupled to the evaporator, and wherein the expander comprises at least one radial type expander, axial type expander, screw type, or impulse type expander.

9. The recovery system of claim 8, wherein rankine cycle system further comprises a condenser coupled to the expander.

10. The recovery system of claim 9, further comprising a pump coupled between the condenser and the evaporator.

11. The recovery system of claim 10, further comprising a control valve situated in a pump bypass path between the condenser and the evaporator, the control valve being operable to control the flow of the working fluid entering the evaporator.

12. The recovery system of claim 11;

wherein the controller is configured to control the pump, pump bypass control valve, condenser fan speed or water flow, expander speed or expander inlet guide vane, heat input from the heat source, or a combination thereof so as to control the thermodynamic conditions at the exit of the expander.

13. The recovery system of claim 6, wherein the controller is configured to control the thermodynamic conditions at the exit of the expander so that a quality of vapor of the working fluid at an inlet of the expander is below one.

14. The recovery system of claim 6, wherein the controller comprises data lookup tables or equations of state;

wherein the controller is configured to calculate vapor quality at an inlet of the expander based on the output signals from the temperature sensor and the pressure sensor, expander efficiency, equations of state, and/or data lookup tables.

15. A method for controlling thermodynamic conditions at an exit of an expander of an expansion system;

the method comprising;

detecting temperature of the working fluid flowing through the exit of the expander;

detecting pressure of the working fluid flowing through the exit of the expander; and

controlling operation of one or more components of the expansion system based on detected temperature and pressure of the working fluid flowing through the exit of the expander so as to drive a quality of vapor of the working fluid at the exit of the expander towards a predetermined degree of superheat.

16. The method of claim 16, wherein the predetermine degree of superheat is zero.

17. The method of claim 16, further comprising maintaining a quality of vapor of the working fluid at an inlet of the expander below one.

18. A method comprising:

circulating a working fluid through a rankine cycle system coupled to a heat source, wherein circulating the working fluid comprises removing heat from the heat source; and

detecting temperature of the working fluid flowing through an exit of an expander of the rankine cycle system;

detecting pressure of the working fluid flowing through the exit of the expander of the rankine cycle system; and

controlling one or more components of the rankine cycle system, heat input from the heat source, or a combination thereof based on detected temperature and pressure of the working fluid flowing through the exit of the expander so as to drive a quality of vapor of the working fluid at the exit of the expander towards a predetermined degree of superheat.

19. The method of claim 18, wherein circulating the working fluid through the rankine cycle system comprises circulating working fluid through an evaporator, expander, and condenser.

20. The method of claim 19, further comprising transferring the working fluid from the condenser to the evaporator via a pump.

21. The method of claim 20, further comprising controlling flow of the working fluid from the condenser to evaporator via a control valve provided in a pump bypass path between the condenser and evaporator.

22. The method of claim 21, comprising controlling the pump speed, pump bypass control valve, condenser fan or water flow, expander, heat input from the heat source or a combination thereof so as to control the thermodynamic conditions at the exit of the expander.

23. The method of claim 18, further comprising controlling the thermodynamic conditions at the exit of the expander so as to maintain quality of vapor of the working fluid at an inlet of the expander less than one.

24. The method of claim 18, wherein the predetermined degree of superheat is zero.