Arrangement comprising a WHR system and a method for controlling such an arrangement

Patent metadata

Field	Value
Publication number	US-11215101-B2
Application number	US-201915734260-A
Country	US
Kind code	B2
Filing date	Jun 17, 2019
Priority date	Jun 20, 2018
Publication date	Jan 4, 2022
Grant date	Jan 4, 2022

Abstract

The present invention relates to an arrangement comprising a waste heat recovery system (WHR-system) and a method for controlling the arrangement. The arrangement comprises an expansion tank having a constant inner volume, first cooling means configured to cool the working fluid in the condenser and a control unit configured to control the first cooling means such that the working fluid is cooled to a desired condensation temperature in the condenser during operation of the WHR system. The arrangement comprises further a sub-cooler arranged in a position downstream of the condenser and second cooling means configured to cool the working fluid in the sub-cooler, and that the control unit is configured to control the second cooling means such that the working fluid receives a determined subcooling in the sub-cooler during operation of the WHR system.

First claim

The invention claimed is:

1. An arrangement comprising a waste heat recovery system (WHR-system), wherein the WHR-system comprises:
a working fluid pump;
an evaporator;
an expander;
a condenser;
an expansion tank having a constant inner volume configured to accommodate working fluid;
first cooling means configured to cool a working fluid in the condenser;
an electronic control unit configured to control the first cooling means such that the working fluid is cooled to a desired condensation temperature in the condenser during operation of the WHR system;
a sub-cooler arranged in a position downstream of the condenser; and
second cooling means configured to cool the working fluid in the sub-cooler,
wherein the electronic control unit controls the second cooling means such that the working fluid receives a determined subcooling in the sub-cooler during operation of the WHR system.

2. An arrangement according to claim 1 , wherein the first cooling means comprises a condenser inlet line and a condenser valve configured to direct coolant from a cooling system to the condenser, and wherein the electronic control unit controls the condenser valve, such that coolant at a temperature and flow is directed, via the condenser inlet line, to the condenser at which the working fluid is cooled to the desired condensation temperature.

3. An arrangement according to claim 1 , wherein the second cooling means comprises a sub-cooler inlet line and a sub-cooler valve configured to direct coolant from a cooling system to the sub-cooler, and wherein the electronic control unit controls the sub-cooler valve, such that coolant at a temperature and flow is directed, via the sub-cooler inlet line, to the sub-cooler at which the working fluid receives the determined subcooling.

4. An arrangement according to claim 2 , wherein the second cooling means comprises a sub-cooler valve configured to direct a part of the coolant flow in the condenser inlet line, via the sub-cooler inlet line, to the sub-cooler.

5. An arrangement according to claim 3 , wherein the sub-cooler inlet line comprises a cooler.

6. An arrangement according to claim 1 , wherein the expansion tank is connected to a flow passage directing working fluid from the condenser to the sub-cooler.

7. An arrangement according to claim 6 , wherein the expansion tank is connected to said flow passage via a single line.

8. An arrangement according to claim 6 , wherein the expansion tank is connected to said flow passage via a tank inlet line and a tank outlet line.

9. An arrangement according to claim 6 , wherein said flow passage extends through the expansion tank.

10. An arrangement according to claim 1 , wherein the arrangement comprises flow restricting means, which, during a shutdown phase of the WHR system, is configured restrict the working fluid flow in the WHR system such that the working fluid pump creates a low pressure area in the WHR system including the expansion tank, and a high pressure area in the WHR system including the evaporator, the expander and the condenser, wherein the electronic control unit control the working fluid pump to run until all working fluid in the high pressure area is in liquid state.

11. An arrangement according to claim 10 , wherein said high pressure area also comprises the sub-cooler.

12. An arrangement according to claim 1 , wherein the arrangement comprises a heater arranged in the expansion tank and tank flow restricting means and that the electronic control unit, during a shutdown phase of the WHR system, controls the heater such that it establishes a higher temperature of the working fluid in the expansion tank than the condensation temperature of the working fluid at ambient pressure, and to isolate the expansion tank from the remaining part of the WHR system when the temperature of the working fluid in the remaining part of the WHR system is lower than the condensation temperature of the working fluid at ambient pressure.

13. An electronically implemented method for controlling a WHR-system, which comprises a working fluid pump, an evaporator, an expander, a condenser, an expansion tank having a constant inner volume configured to accommodate working fluid, wherein the method comprises, via operation of an electronic control unit:
cooling of the working fluid in the condenser to a desired condensation temperature by controlling a first cooling means during a regular operation phase of the WHR system; and
cooling the working fluid in a sub-cooler, which is arranged downstream of the condenser, such that the working fluid receives a desired subcooling in the sub-cooler by controlling a second cooling means during the regular operation phase of the WHR system.

14. An electronically implemented method according to claim 13 further comprising, via operation of the electronic control unit:
during a shutdown phase of the WHR system, restricting flow of the working fluid in the WHR system, such that the working fluid pump creates a low pressure area in the WHR system including the expansion tank and a high pressure area including the evaporator, the expander and the condenser; and
running the working fluid pump until all working fluid in the high pressure area is in liquid state.

15. An electronically implemented method according to claim 13 further comprising, via operation of the electronic control unit:
during a shutdown phase of the WHR system, controlling a heater to heat the working fluid in the expansion tank to a higher temperature than the condensation temperature of the working fluid at ambient pressure; and
isolating the expansion tank from the other parts of the WHR system when the temperature of the working fluid in the other part of the WHR system is lower than the condensation temperature of the working fluid at ambient pressure.

Assignees

• Scania Cv Ab

Inventors

• Kardos Zoltan
• Hall Ola
• Sederholm Thomas

Classifications

• F02G5/02 Primary

  Profiting from waste heat of exhaust gases · CPC title

• F01N5/02 Primary

  the devices using heat · CPC title

• F01K23/14

  including at least one combustion engine · CPC title

• F01K15/02

  for driving vehicles, e.g. locomotives · CPC title

• F01K9/003

  condenser cooling circuits · CPC title