Heat Engine and Heat to Electricity Systems and Methods with Working Fluid Mass Management Control

• US 20140096524A1
• Filed: 12/11/2013
• Published: 04/10/2014
• Est. Priority Date: 09/17/2009
• Status: Active Grant

• Current Assignee: Echogen Power Systems, LLC
• Original Assignee: Echogen Power Systems, LLC
• Inventors: Held, Timothy James, Hostler, Stephen, Miller, Jason D., Vermeersch, Michael, Xie, Tao
• Granted Patent: US 9,458,738 B2
• Time in Patent Office: Days
• US Class Current: 60/651
• CPC Class Codes: F01K 25/103 Carbon dioxide F01K25/065 takes precedence
• CPC Class Codes: F01K 3/185 using waste heat from outside the plant F02G5/00 takes precedence
• CPC Class Codes: F01K 7/08 Control means specially adapted therefor
• CPC Class Codes: F24H 2240/12 with thermodynamic cycle for converting thermal energy to mechanical power to produce electrical energy

Abstract

Aspects of the disclosure generally provide a heat engine system and a method for regulating a pressure and an amount of a working fluid in a working fluid circuit during a thermodynamic cycle. A mass management system may be employed to regulate the working fluid circulating throughout the working fluid circuit. The mass management systems may have a mass control tank fluidly coupled to the working fluid circuit at one or more strategically-located tie-in points. A heat exchanger coil may be used in conjunction with the mass control tank to regulate the temperature of the fluid within the mass control tank, and thereby determine whether working fluid is either extracted from or injected into the working fluid circuit. Regulating the pressure and amount of working fluid in the working fluid circuit selectively increases or decreases the suction pressure of the pump to increase system efficiency.

Claims

1. A heat engine system, comprising:

a working fluid circuit configured to circulate a working fluid through a high pressure side and a low pressure side of the working fluid circuit;

a first heat exchanger fluidly coupled to the working fluid circuit, configured to be fluidly coupled to and in thermal communication with a heat source, and configured to transfer thermal energy from the heat source to the working fluid within the high pressure side of the working fluid circuit;

a second heat exchanger fluidly coupled to the working fluid circuit, configured to be fluidly coupled to and in thermal communication with the heat source, and configured to transfer thermal energy from the heat source to the working fluid within the high pressure side of the working fluid circuit;

an expander fluidly coupled to the working fluid circuit between the low pressure side and the high pressure side and disposed downstream of the first heat exchanger or the second heat exchanger in the working fluid circuit;

a recuperator fluidly coupled to the low pressure side and the high pressure side of the working fluid circuit and configured to transfer thermal energy between the low pressure side and the high pressure side;

a cooler fluidly coupled to the working fluid circuit, disposed downstream of the recuperator, and configured to control a temperature of the working fluid in the low pressure side;

a pump fluidly coupled to the working fluid circuit between the low pressure side and the high pressure side, disposed downstream of the cooler, and configured to circulate the working fluid through the working fluid circuit; and

a mass management system fluidly coupled to the working fluid circuit and configured to regulate a pressure and an amount of the working fluid within the working fluid circuit, the mass management system further comprises;

a mass control tank fluidly coupled to the working fluid circuit at one or more tie-in points on the working fluid circuit; and

a control system communicably coupled to the working fluid circuit at a first sensor disposed upstream of an inlet of the pump and at a second sensor disposed downstream of an outlet of the pump, and communicably coupled to the mass control tank at a third sensor disposed either within or adjacent the mass control tank.

2. The heat engine system of claim 1, wherein the working fluid comprises carbon dioxide.

3. The heat engine system of claim 1, wherein the mass management system further comprises a heat exchanger coil configured to transfer heat to and from the mass control tank.

4. The heat engine system of claim 3, wherein the heat exchanger coil is disposed within the mass control tank.

5. The heat engine system of claim 3, wherein the heat exchanger coil is fluidly coupled to the cooler and configured to use thermal fluid derived from the cooler to heat or cool the working fluid in the mass control tank.

6. The heat engine system of claim 3, wherein the heat exchanger coil is fluidly coupled to the working fluid circuit downstream of the pump and configured to use the working fluid discharged from the pump to heat or cool the working fluid in the mass control tank.

7. The heat engine system of claim 1, wherein the recuperator is configured to transfer thermal energy from the working fluid in the low pressure side to the working fluid in the high pressure side.

8. The heat engine system of claim 1, wherein at least one of the tie-in points is disposed upstream of the inlet of the pump on the low pressure side of the working fluid circuit.

9. The heat engine system of claim 1, wherein the one or more tie-in points on the working fluid circuit further comprises:

a first tie-in point disposed on the working fluid circuit, fluidly coupled to the mass control tank, and configured to flow the working fluid from the working fluid circuit to the mass control tank; and

a second tie-in point disposed on the working fluid circuit, fluidly coupled to the mass control tank, and configured to flow the working fluid from the mass control tank to the working fluid circuit.

10. The heat engine system of claim 9, wherein the second tie-in point is disposed upstream of the inlet of the pump on the low pressure side of the working fluid circuit.

11. The heat engine system of claim 9, further comprising:

a first valve disposed between the mass control tank and the first tie-in point; and

a second valve disposed between the mass control tank and the second tie-in point.

12. The heat engine system of claim 11, wherein the control system is operatively coupled to and configured to selectively actuate the first valve and the second valve in response to operating parameters derived from the first sensor, the second sensor, or the third sensor.

13. The heat engine system of claim 11, wherein the mass control tank is further fluidly coupled to the high pressure side of the working fluid circuit at a third tie-in point disposed downstream of the pump, a third valve is disposed between the mass control tank and the third tie-in point, and the control system is operatively coupled to and configured to selectively actuate the third valve in response to operating parameters derived from the first sensor, the second sensor, or the third sensor.

14. The heat engine system of claim 11, wherein the mass management system further comprises a transfer pump disposed between the mass control tank and the second tie-in point, wherein the transfer pump is configured to transfer the working fluid from the mass control tank and into the working fluid circuit via the second tie-in point.

15. A heat engine system, comprising:

a working fluid circuit configured to circulate a working fluid through a high pressure side and a low pressure side of the working fluid circuit, wherein the working fluid comprises carbon dioxide;

a heat exchanger fluidly coupled to the working fluid circuit, configured to be fluidly coupled to and in thermal communication with a heat source, and configured to transfer thermal energy from the heat source to the working fluid within the high pressure side of the working fluid circuit;

an expander fluidly coupled to the working fluid circuit between the low pressure side and the high pressure side and disposed downstream of the heat exchanger in the working fluid circuit;

a recuperator fluidly coupled to the low pressure side and the high pressure side of the working fluid circuit and configured to transfer thermal energy between the low pressure side and the high pressure side;

a cooler fluidly coupled to the working fluid circuit, disposed downstream of the recuperator, and configured to control a temperature of the working fluid in the low pressure side;

a pump fluidly coupled to the working fluid circuit between the low pressure side and the high pressure side, disposed downstream of the cooler, and configured to circulate the working fluid through the working fluid circuit; and

a mass management system fluidly coupled to the working fluid circuit and configured to regulate a pressure and an amount of the working fluid within the working fluid circuit, the mass management system further comprises;

a mass control tank fluidly coupled to the working fluid circuit; and

a control system communicably coupled to the working fluid circuit at a first sensor disposed upstream of an inlet of the pump and at a second sensor disposed downstream of an outlet of the pump, and communicably coupled to the mass control tank at a third sensor disposed either within or adjacent the mass control tank.

16. A method for regulating a pressure and an amount of a working fluid in a thermodynamic cycle, comprising:

placing a thermal energy source in thermal communication with a heat exchanger disposed within a working fluid circuit, the working fluid circuit containing the working fluid and having a high pressure side and a low pressure side, and the working fluid comprises carbon dioxide;

circulating the working fluid through the working fluid circuit with a pump;

expanding the working fluid in an expander to generate mechanical energy;

sensing operating parameters of the working fluid circuit with first and second sensor sets communicably coupled to a control system, wherein the first sensor set is configured to sense at least one of an inlet pressure and an inlet temperature proximate an inlet of the pump, and the second sensor set is configured to sense at least one of an outlet pressure and an outlet temperature proximate an outlet of the pump;

extracting the working fluid from the working fluid circuit at a first tie-in point on the working fluid circuit and transferring the working fluid to a mass control tank fluidly coupled to the first tie-in point; and

injecting the working fluid from the mass control tank into the working fluid circuit via a second tie-in point on the working fluid circuit while increasing a suction pressure of the pump.

17. The method of claim 16, further comprising extracting additional working fluid from the working fluid circuit at a third tie-in point disposed between the pump and the heat exchanger.

18. The method of claim 16, wherein injecting the working fluid from the mass control tank into the working fluid circuit via the second tie-in point further comprises transferring the working fluid into the working fluid circuit with a transfer pump disposed between the second tie-in point and the mass control tank.

19. The method of claim 16, further comprising sensing operating parameters of the mass control tank with a third sensor set configured to sense at least one of a pressure and a temperature either within or adjacent the mass control tank, wherein the third sensor set is communicably coupled to the control system.

20. The method of claim 16, further comprising cooling the working fluid within the mass control tank with a vapor compression refrigeration cycle having a vapor compressor and a condenser fluidly coupled to the mass control tank.