Heat engine cycles for high ambient conditions

• US 8,857,186 B2
• Filed: 11/07/2011
• Issued: 10/14/2014
• 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
• Primary Examiner(s): NGUYEN, HOANG M
• Application Number:
  US13/291,086
• Publication Number:
  US 20120131921A1
• Time in Patent Office: 1,072 Days
• Field of Search: 606/55, 606/50, 606/70, 606/82, 606/84
• US Class Current: 60/655
• CPC Class Codes: F01K 25/08 using special vapours

Abstract

A system for converting thermal energy to work. The system includes a working fluid circuit, and a precooler configured to receive the working fluid. The system also includes a compression stages and intercoolers. At least one of the precooler and the intercoolers is configured to receive a heat transfer medium from a high temperature ambient environment. The system also includes heat exchangers coupled to a source of heat and being configured to receive the working fluid. The system also includes turbines coupled to one or more of the heat exchangers and configured to receive heated working fluid therefrom. The system further includes recuperators fluidly coupled to the turbines, the precooler, the compressor, and at least one of the heat exchangers. The recuperators transfer heat from the working fluid downstream from the turbines, to the working fluid upstream from at least one of the heat exchangers.

Claims

1. A system for converting thermal energy to work in high ambient temperature conditions, comprising:

first and second compression stages fluidly coupled together such that the first compression stage is upstream of the second compressor stage, the first and second compression stages being configured to compress a working fluid in a working fluid circuit, the working fluid being separated into a first mass flow and a second mass flow downstream from the second compression stage;

an intercooler disposed upstream from the second compression stage and downstream from the first compression stage;

first and second heat exchangers coupled to a source of heat and disposed downstream from the second compression stage, the first heat exchanger being configured to transfer heat from the source of heat to the first mass flow and the second heat exchanger configured to transfer heat from the source of heat to the second mass flow;

first and second turbines, the first turbine configured to receive the first mass flow from the first heat exchanger and the second turbine configured to receive the second mass flow from the second heat exchanger;

a first recuperator disposed downstream from the first turbine on a high temperature side of the working fluid circuit and between the second compression stage and the second turbine on a low temperature side of the working fluid circuit, the first recuperator being configured to transfer heat from the working fluid on the high temperature side to working fluid on the low temperature side; and

a second recuperator disposed downstream from the second turbine on the high temperature side and between the second compression stage and the second turbine on the low temperature side, the second recuperator being configured to transfer heat from the working fluid on the high temperature side to working fluid on the low temperature side.

2. The system of claim 1, further comprising:

a third compression stage disposed downstream from the second compression stage and configured to further compress the working fluid; and

a second intercooler interposed between the second and third compressions stages.

3. The system of claim 1, further comprising a precooler disposed upstream from the first compression stage and configured to cool a combined flow of the first and second mass flows, wherein at least one of the precooler and the intercooler is configured to receive a heat transfer medium from an ambient environment, and a temperature of the ambient environment is between about 30°

C. and about 50°

C.

4. The system of claim 1, wherein the first and second mass flow of the working fluid on the low temperature side upstream from the at least one of the first and second recuperators has a temperature of between about 50°

C. and about 70°

C.

5. The system of claim 1, wherein the combined first and second mass flow of the working fluid on high temperature side downstream from the second recuperator and upstream from the precooler has a temperature of between about 70°

C. and about 110°

C.

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

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

8. The system of claim 1, wherein the working fluid is at a supercritical state at an inlet of the first compression stage.

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

10. The system of claim 1, wherein, on the high temperature side, the first mass flow downstream from the first recuperator and the second mass flow upstream from the second recuperator are combined and introduced to the second recuperator.

11. The system of claim 1, wherein, on the high temperature side, the first mass flow downstream from the first recuperator and the second mass flow downstream from the second recuperator are combined and introduced to the precooler.

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 plurality of compression stages fluidly coupled together in series and configured to compress and circulate a working fluid in a working fluid circuit having a low pressure side and a high pressure side;

one or more intercoolers, each being disposed between two of the plurality of compression stages and configured to cool the working fluid, at least one of the one or more intercoolers being configured to receive a heat transfer medium from an ambient environment, the ambient environment having a temperature of between about 30°

C. and about 50°

C.;

first and second heat exchangers fluidly coupled in series to a source of heat and fluidly coupled to the working fluid circuit, the first heat exchanger configured to receive a first mass flow of the working fluid and second heat exchanger configured to receive a second mass flow of the working fluid;

a first turbine configured to receive the first mass flow of working fluid from the first heat exchanger;

a second turbine configured to receive the second mass flow of working fluid from the second heat exchanger, wherein the plurality of compression stages and the one or more intercoolers are disposed upstream of the first heat exchanger, the second heat exchanger, the first turbine, and the second turbine on the low pressure side of the working fluid circuit; and

a plurality of recuperators, the plurality of recuperators being configured to transfer heat from the first mass flow downstream from the first turbine to working fluid upstream from the first heat exchanger, and configured to transfer heat from at least the second mass flow downstream from the second turbine to at least the second mass flow upstream from the second heat exchanger.

14. The system of claim 13, wherein the plurality of recuperators comprise first and second recuperators coupled together in series on a high temperature side of the working fluid circuit and disposed in parallel on a low temperature side of the working fluid circuit, wherein the first recuperator receives the first mass flow from the first turbine, and the second recuperator receives the first mass flow from the first recuperator and the second mass flow from the second turbine.

15. The system of claim 13, wherein the first and second recuperators are fluidly coupled in parallel on a high temperature side of the working fluid circuit and on a low temperature side of the working fluid circuit.

16. The system of claim 13, further comprising a precooler disposed upstream from the first compression stage and configured to receive and cool a combined flow of the first and second mass flows.

17. The system of claim 16, wherein a combined flow of the first and second mass flows on the high temperature side, upstream from the precooler and downstream from the plurality of recuperators, has a temperature of between about 70°

C. and about 110°

C.

18. The system of claim 13, wherein the first and second mass flows of the working fluid on the low temperature side, upstream from the plurality of recuperators, have a temperature of between about 50°

C. and about 70°

C.

19. The system of claim 13, wherein the heat source is a waste heat stream and the working fluid is carbon dioxide, the carbon dioxide being at a supercritical state at an inlet to the first compression stage.

20. The system of claim 13, wherein the plurality of recuperators comprises a single recuperator component.

21. A system for converting thermal energy to work in a high ambient temperature environment, comprising:

a working fluid circuit having a high temperature side and a low temperature side, the working fluid circuit containing a working fluid comprising carbon dioxide;

a precooler configured to receive the working fluid from the high temperature side;

a compressor having a plurality of stages and one or more intercoolers configured to cool the working fluid between at least two of the plurality of stages, the compressor configured to receive the working fluid from the precooler, wherein at least one of the precooler and the one or more intercoolers is configured to receive a heat transfer medium from the ambient environment, the ambient environment having a temperature of between about 30°

C. and about 50°

C.;

a plurality of heat exchangers coupled to a source of heat, the plurality of heat exchangers being configured to receive fluid from the low temperature side and discharge fluid to the high temperature side;

a plurality of turbines disposed on the high temperature side of the working fluid circuit, each of the plurality of turbines being coupled to one or more of the plurality of heat exchangers and configured to receive heated working fluid therefrom; and

a plurality of recuperators, each of the plurality of recuperators being coupled the high and low temperature sides of the working fluid circuit, the plurality of recuperators being coupled, on the high temperature side, to at least one of the plurality of turbines and to the precooler and, on the low temperature side, to the compressor and at least one of the plurality of heat exchangers, the plurality of recuperators being configured to transfer heat from the high temperature side, downstream from at least one of the plurality of turbines, to the working fluid, upstream from at least one of the plurality of heat exchangers.