DUAL CYCLE RANKINE WASTE HEAT RECOVERY CYCLE

• US 20110308253A1
• Filed: 06/21/2010
• Published: 12/22/2011
• Est. Priority Date: 06/21/2010
• Status: Active Grant

• Current Assignee: PACCAR Incorporated
• Original Assignee: PACCAR Incorporated
• Inventors: Ritter, Jason
• Granted Patent: US 9,046,006 B2
• Time in Patent Office: Days
• US Class Current: 60/661
• CPC Class Codes: F01K 23/04 condensation heat from one cycle heating the fluid in another cycle
• CPC Class Codes: F01K 23/065 the combustion taking place in an internal combustion piston engine, e.g. a diesel engine
• CPC Class Codes: F01K 25/08 using special vapours
• CPC Class Codes: F22B 1/1807 using the exhaust gases of combustion engines
• CPC Class Codes: Y02E 20/30 Technologies for a more efficient combustion or heat usage
• CPC Class Codes: Y02P 80/15 On-site combined power, heat or cool generation or distribution, e.g. combined heat and power [CHP] supply
• CPC Class Codes: Y02T 10/12 Improving ICE efficiencies

Abstract

A dual cycle waste heat recovery system includes a high-temperature circuit that utilizes a first working fluid. The first working fluid is heated by a first waste heat source and then expanded through a first expander to produce power. The heat recovery system further includes a low-temperature circuit that utilizes a second working fluid. The low-temperature circuit also includes a first heat exchanger for heating the second working fluid with heat from the first working fluid and a second heat exchanger for heating the second working fluid with heat from a second waste heat source. A control valve selectively controls the flow of the second working fluid to each of the first and second heat exchangers according to a predetermined set of parameters. An expander receives the second working fluid from the first and second heat exchangers and expands the second working fluid to produce power.

Claims

1. A dual cycle waste heat recovery system, comprising:

(a) a high-temperature circuit having a first working fluid, wherein the first working fluid is (1) heated by a first waste heat source, and (2) expanded through a first expander to produce power; and

(b) a low-temperature circuit, comprising;

(i) a second working fluid;

(ii) a first heat exchanger for heating the second working fluid with heat from the first working fluid;

(iii) a second heat exchanger for heating the second working fluid with heat from a second waste heat source;

(iv) a control valve for selectively controlling a flow of the second working fluid to each of the first and second heat exchangers according to a predetermined set of parameters; and

(v) an expander for receiving the second working fluid from the first and second heat exchangers, wherein the expander expands the second working fluid to produce power.

2. The system of claim 1, wherein the predetermined set of parameters comprises an amount of heat available from the first working fluid.

3. The system of claim 2, wherein the amount of heat available from the first working fluid is determined at least in part by a temperature of the first working fluid.

4. The system of claim 3, further comprising a temperature sensor for sensing the temperature of the first working fluid.

5. The system of claim 2, wherein the amount of heat available from the first working fluid is determined at least in part by a mass flow and temperature of the first working fluid.

6. The system of claim 3, further comprising a mass flow sensor for sensing the mass flow of the first working fluid.

7. The system of claim 6, further comprising a temperature sensor for sensing the temperature of the first working fluid.

8. The system of claim 7, wherein the temperature of the first working fluid is used to determine an enthalpy of the first working fluid, and the amount of heat available from the first working fluid is determined by multiplying the enthalpy of the first working fluid by the mass flow of the first working fluid.

9. The system of claim 2, wherein the predetermined set of parameters further comprises an amount of heat available from the second waste heat source.

10. The system of claim 9, wherein the amount of heat available from the second working fluid is determined at least in part by a temperature of the second working fluid.

11. The system of claim 9, wherein the amount of heat available from the second working fluid is determined at least in part by a mass flow and temperature of the second working fluid.

12. The system of claim 9, wherein the control valve directs at least a portion of the second working fluid to the first heat exchanger when the amount of heat available from the first working fluid is greater than the amount of heat available from the second waste heat source.

13. The system of claim 12, wherein the control valve directs at least a portion of the second working fluid to the second heat exchanger when the amount of heat available from the second waste heat source is greater than the amount of heat available from the first working fluid.

14. The system of claim 1, further comprising a third heat exchanger for heating the second working fluid with heat from a third waste heat source, wherein the control valve selectively controls the flow of the second working fluid to each of the first, second, and third heat exchangers according to a predetermined set of parameters.

16. The system of claim 1, wherein the predetermined set of parameters includes an amount of heat available from at least one of the second heat exchanger and the third heat exchanger.

15. A dual cycle waste heat recovery system, comprising:

(a) a high-temperature circuit, comprising;

(i) a first working fluid;

(ii) a first heat exchanger for heating the first working fluid;

(iii) a first expander for receiving the first working fluid from the first heat exchanger and expanding the first working fluid to produce power; and

(iv) a second heat exchanger for receiving the first working fluid from the first expander and cooling the first working fluid; and

(b) a low-temperature circuit, comprising;

(i) a second working fluid;

(ii) a valve for selectively directing the second working fluid to be heated by one of the second heat exchanger and a third heat exchanger;

(iii) a second expander for receiving the second working fluid from the one of the second heat exchanger and third heat exchanger, and expanding the second working fluid to produce power; and

(iv) a controller for controlling the valve to direct the second working fluid selectively to one of the second heat exchanger and the third heat exchanger according to a predetermined set of parameters.

17. A dual cycle waste heat recovery system, comprising:

(a) a first heat recovery circuit, comprising;

(i) a first working fluid;

(ii) a first heat exchanger for heating the first working fluid;

(iii) a first expander for receiving the first working fluid from the first heat exchanger and expanding the first working fluid to produce power; and

(iv) a second heat exchanger for receiving the first working fluid from the first expander and cooling the first working fluid; and

(b) a second heat recovery circuit, comprising;

(i) a second working fluid;

(ii) a third heat exchanger for heating the second working fluid with heat from a first heat source;

(iii) a fourth heat exchanger for heating the second working fluid with heat from a second heat source;

(iv) a valve for selectively directing the second working fluid to the one of the second heat exchanger, the third heat exchanger, and the fourth heat exchanger having the heat source with the highest temperature, wherein the first working fluid is a heat source for the second working fluid in the second heat exchanger; and

(v) a second expander for receiving the second working fluid from the one of the second heat exchanger, the third heat exchanger, and the fourth heat exchanger and expanding the second working fluid to produce power.