PARALLEL CYCLE HEAT ENGINES

• US 20120131920A1
• Filed: 08/18/2011
• Published: 05/31/2012
• Est. Priority Date: 11/29/2010
• Status: Active Grant

• Current Assignee: Echogen Power Systems, LLC
• Original Assignee: Echogen Power Systems, LLC
• Inventors: Held, Timothy James, Vermeersch, Michael Louis, Xie, Tao, Miller, Jason
• Granted Patent: US 9,284,855 B2
• Time in Patent Office: Days
• US Class Current: 60/650
• CPC Class Codes: F01K 13/02 Controlling, e.g. stopping or starting
• CPC Class Codes: F01K 23/04 condensation heat from one cycle heating the fluid in another cycle
• CPC Class Codes: F01K 25/10 the vapours being cold, e.g. ammonia, carbon dioxide, ether
• CPC Class Codes: F01K 25/103 Carbon dioxide F01K25/065 takes precedence
• CPC Class Codes: F22B 35/086 operating at critical or supercritical pressure

Abstract

Waste heat energy conversion cycles, systems and devices use multiple waste heat exchangers arranged in series in a waste heat stream, and multiple thermodynamic cycles run in parallel with the waste heat exchangers in order to maximize thermal energy extraction from the waste heat stream by a working fluid. The parallel cycles operate in different temperature ranges with a lower temperature work output used to drive a working fluid pump. A working fluid mass management system is integrated into or connected to the cycles.

Claims

1. A system for converting thermal energy to work, comprising:

a pump configured to circulate a working fluid throughout a working fluid circuit, the working fluid being separated into a first mass flow and a second mass flow downstream from the pump;

a first heat exchanger fluidly coupled to the pump and in thermal communication with a heat source, the first heat exchanger being configured to receive the first mass flow and transfer heat from the heat source to the first mass flow;

a first turbine fluidly coupled to the first heat exchanger and configured to expand the first mass flow;

a first recuperator fluidly coupled to the first turbine and configured to transfer residual thermal energy from the first mass flow discharged from the first turbine to the first mass flow directed to the first heat exchanger;

a second heat exchanger fluidly coupled to the pump and in thermal communication with the heat source, the second heat exchanger being configured to receive the second mass flow and transfer heat from the heat source to the second mass flow; and

a second turbine fluidly coupled to the second heat exchanger and configured to expand the second mass flow.

2. The system of claim 1, wherein the heat source is a waste heat stream.

3. The system of claim 1, wherein the working fluid is carbon dioxide.

4. The system of claim 1, wherein the working fluid is at a supercritical state at an inlet to the pump.

5. The system of claim 1, wherein the first and second heat exchangers are arranged in series in the heat source.

6. The system of claim 1, wherein the first mass flow circulates in parallel with the second mass flow.

7. The system of claim 1, further comprising a second recuperator fluidly coupled to the second turbine and configured to transfer residual thermal energy from the second mass flow discharged from the second turbine to the second mass flow directed to the second heat exchanger.

8. The system of claim 7, wherein the first and second recuperators are arranged in series on a low temperature side of the working fluid circuit, and the first and second recuperators are arranged in parallel on a high temperature side of the working fluid circuit.

9. The system of claim 1, further comprising a second recuperator fluidly coupled to the second turbine and configured to transfer residual thermal energy from a combined first and second mass flow to the first mass flow directed to the first heat exchanger.

10. The system of claim 1, wherein an inlet pressure at the first turbine is substantially equal to an inlet pressure at the second turbine.

11. The system of claim 10, wherein a discharge pressure at the first turbine is different than a discharge pressure at the second turbine.

12. The system of claim 1, further comprising a mass management system operatively connected to the working fluid circuit via at least two tie-in points, the mass management system being configured to control the amount of working fluid within the working fluid circuit.

13. A system for converting thermal energy to work, comprising:

a pump configured to circulate a working fluid throughout a working fluid circuit, the working fluid being separated into a first mass flow and a second mass flow downstream from the pump;

a first heat exchanger fluidly coupled to the pump and in thermal communication with a heat source, the first heat exchanger being configured to receive the first mass flow and transfer heat from the heat source to the first mass flow;

a first turbine fluidly coupled to the first heat exchanger and configured to expand the first mass flow;

a first recuperator fluidly coupled to the first turbine and configured to transfer residual thermal energy from the first mass flow discharged from the first turbine to the first mass flow directed to the first heat exchanger;

a second heat exchanger fluidly coupled to the pump and in thermal communication with the heat source, the second heat exchanger being configured to receive the second mass flow and transfer heat from the heat source to the second mass flow;

a second turbine fluidly coupled to the second heat exchanger and configured to expand the second mass flow, the second mass flow being discharged from the second turbine and re-combined with the first mass flow to generate a combined mass flow;

a second recuperator fluidly coupled to the second turbine and configured to transfer residual thermal energy from the combined mass flow to the second mass flow directed to the second heat exchanger; and

a third heat exchanger in thermal communication with the heat source and arranged between the pump and the first heat exchanger, the third heat exchanger being configured to receive and transfer heat to the first mass flow prior to passing through the first heat exchanger.

14. The system of claim 13, wherein the heat source is a waste heat stream.

15. The system of claim 13, wherein the working fluid is carbon dioxide.

16. The system of claim 13, wherein the working fluid is at a supercritical state at an inlet to the pump.

17. The system of claim 13, wherein the first, second, and third heat exchangers are arranged in series in the waste heat stream, and the first mass flow circulates in parallel with the second mass flow.

18. The system of claim 13, wherein the first and second recuperators comprise a single recuperator component.

19. The system of claim 13, wherein the first and second recuperators are arranged in series in a low temperature side of the working fluid circuit, and the first and second recuperators are arranged in parallel in a high temperature side of the working fluid circuit.

20. The system of claim 13, further comprising a third recuperator arranged between the pump and the third heat exchanger.

21. The system of claim 20, wherein the third recuperator is configured to transfer residual heat from the combined mass flow discharged from the second recuperator to the first mass flow before the first mass flow is introduced into the third heat exchanger.

22. The system of claim 21, wherein the first, second, and third recuperators are arranged in series in a low temperature side of the working fluid circuit and in parallel in a high temperature side of the working fluid circuit.

23. The system of claim 18, wherein the first, second, and third recuperators comprise a single recuperator component.

24. The system of claim 20, wherein the single recuperator component is configured to receive the first mass flow discharged from the third heat exchanger to transfer additional residual thermal energy from the combined mass flow to the first mass flow prior to the first mass flow passing through the first heat exchanger.

25. The system of claim 13, wherein an inlet pressure at the first turbine is substantially equal to an inlet pressure at the second turbine.

26. The system of claim 25, wherein a discharge pressure at the first turbine is different than a discharge pressure at the second turbine.

27. A method for converting thermal energy to work, comprising:

circulating a working fluid with a pump throughout a working fluid circuit;

separating the working fluid in the working fluid circuit into a first mass flow and a second mass flow;

transferring thermal energy in a first heat exchanger from a heat source to the first mass flow, the first heat exchanger being in thermal communication with the heat source;

expanding the first mass flow in a first turbine fluidly coupled to the first heat exchanger;

transferring residual thermal energy in a first recuperator from the first mass flow discharged from the first turbine to the first mass flow directed to the first heat exchanger, the first recuperator being fluidly coupled to the first turbine;

transferring thermal energy in a second heat exchanger from the heat source to the second mass flow, the second heat exchanger being in thermal communication with the heat source; and

expanding the second mass flow in a second turbine fluidly coupled to the second heat exchanger.

28. The method of claim 27, further comprising transferring residual thermal energy in a second recuperator from the second mass flow discharged from the second turbine to the second mass flow directed to the second heat exchanger, the second recuperator being fluidly coupled to the second turbine.

29. The method of claim 28, further comprising transferring thermal energy in a third heat exchanger from the heat source to the first mass flow prior to passing through the first heat exchanger, the third heat exchanger being in thermal communication with the heat source and arranged between the pump and the first heat exchanger.

30. The method of claim 29, further comprising transferring residual heat in a third recuperator from a combined first and second mass flow discharged from the second recuperator to the first mass flow before the first mass flow is introduced into the third heat exchanger, the third recuperator being arranged between the pump and the third heat exchanger.

31. The method of claim 27, further comprising transferring residual thermal energy in a second recuperator from a combined first and second mass flow to the first mass flow directed to the first heat exchanger, the second recuperator being fluidly coupled to the second turbine.