Thermal management systems for extended operation

Patent metadata

Field	Value
Publication number	US-11644251-B2
Application number	US-202217846916-A
Country	US
Kind code	B2
Filing date	Jun 22, 2022
Priority date	Jun 22, 2021
Publication date	May 9, 2023
Grant date	May 9, 2023

Abstract

A thermal management system includes a closed-circuit refrigeration system (CCRS) that includes a vapor cycle system (VCS). The VCS includes a receiver configured to store a refrigerant fluid; a liquid separator; a compressor; a condenser; at least one evaporator configured to extract heat from at least one heat load that is in thermal conductive or convective contact with the evaporator; and a thermal energy storage (TES) that stores a phase change material. The thermal management system further includes a liquid pumping system (LPS) that includes the TES, the at least one evaporator, and the liquid separator, with the LPS further including a pump. The VCS is configured to operate one at a time in at least one of three operational modes that are a TES cooling mode, a heat load cooling mode, or a pump-down mode. The LPS is configured to operate in the heat load cooling mode.

First claim

What is claimed is:

1. A thermal management system, comprising:
a closed-circuit refrigeration system (CCRS) comprising:
a vapor cycle system (VCS) comprising:
a receiver configured to store a refrigerant fluid;
a liquid separator comprising an inlet, a vapor-side outlet and a liquid-side outlet;
a compressor comprising a compressor inlet fluidly coupled to the vapor-side outlet;
a condenser fluidly coupled to a compressor outlet of the compressor;
at least one evaporator comprising an evaporator inlet coupled in the VCS, with the evaporator configured to extract heat from at least one heat load that is in proximity to or in thermal conductive or convective contact with the at least one evaporator;
an expansion valve comprising an inlet coupled to an outlet of the receiver; and
a thermal energy storage (TES) that stores a phase change material, the TES comprising a heat exchanger that provides thermal interaction between the phase change material and the refrigerant fluid;

a liquid pumping system (LPS) that comprises the TES, the at least one evaporator, and the liquid separator, the liquid pumping system further comprising a pump, the pump configured to circulate liquid refrigerant from the liquid-side outlet of the liquid separator into the evaporator inlet; and
wherein the VCS is configured to operate one at a time in at least one of three operational modes that are a TES cooling mode, a heat load cooling mode, or a pump-down mode, and the LPS is configured to operate in the heat load cooling mode.

2. The system of claim 1 , wherein the TES cooling mode charges the TES and the phase change material in the TES by directing refrigerant through the TES from the receiver causing cooling energy from the refrigerant fluid to be stored in the phase change material in latent heat form.

3. The system of claim 1 , wherein the liquid pumping system is configured to evaporate refrigerant fluid at a temperature in a range that is below a heat load temperature low limit and above a phase change material freezing temperature.

4. The system of claim 1 , wherein, in the pump-down mode, the refrigerant liquid accumulated in the liquid separator is returned to the receiver.

5. The system of claim 1 , further comprising a recuperative heat exchanger comprising a pair of refrigerant fluid paths, with a first refrigerant fluid path coupled downstream of the receiver and a second refrigerant fluid path coupled upstream of the liquid separator.

6. The system of claim 1 , wherein the refrigerant comprises ammonia or carbon dioxide.

7. The system of claim 1 , further comprising at least one heat load that is cooled by the TES operating in the heat load cooling mode.

8. The system of claim 7 , wherein the liquid pumping system is configured to cool the at least one heat load by discharging the stored cooling energy from the phase change material to the at least one evaporator.

9. The system of claim 1 , wherein the expansion valve is configured to iso-enthalpically expand the liquid refrigerant from the receiver to a low-pressure, two-phase refrigerant fluid.

10. The system of claim 9 , wherein a portion of a refrigerant liquid of the low-pressure, two-phase refrigerant fluid phase evaporates to cool the phase change material in the TES, with the liquid separator disposed to receive non-evaporated refrigerant liquid.

11. The system of claim 1 , wherein the expansion valve is a first expansion valve and the TES is a first TES, the system further comprising:
a second expansion valve comprising an inlet coupled to the outlet of the receiver;
a second TES comprising an inlet coupled to an outlet of the second expansion valve and an outlet coupled to the inlet of the liquid separator, and
wherein the system implements the following sequence with the first TES cooling a low heat load with the VCS off, the second TES cooling the low heat load, and the VCS cooling the first TES and the low heat load is OFF, and the VCS cooling the second TES.

12. The system of claim 11 , wherein the pump is configured to circulate refrigerant liquid from the liquid-side outlet through at least one of first or second TES to subcool the refrigerant liquid and transport the subcooled refrigerant liquid to the evaporator, causing complete or partial evaporation of the refrigerant, with refrigerant vapor formed in the evaporator being captured by the liquid separator.

13. The system of claim 1 , wherein the VCS operates according to a transcritical refrigeration cycle or a subcritical refrigeration cycle.

14. The system of claim 13 , wherein when the VCS operates in the transcritical refrigeration cycle, the condenser operates as a gas cooler, and the compressor induces refrigerant vapor from the vapor-side outlet of the liquid separator at a low pressure and compresses the refrigerant vapor at the low pressure into a refrigerant vapor at a high pressure and high temperature, with the refrigerant vapor at the high pressure and high temperature being cooled in the gas cooler.

15. The system of claim 13 , wherein when the VCS operates in a subcritical refrigeration cycle, the compressor induces refrigerant vapor from the vapor-side outlet of the liquid separator at a low pressure and compresses the refrigerant vapor at the low pressure into a refrigerant vapor at a high pressure and temperature, with the refrigerant vapor in the condenser being de-superheated, condensed, and subcooled.

16. The system of claim 1 , wherein the pump is configured to circulate liquid refrigerant from the liquid-side outlet of the liquid separator into an inlet of the TES.

17. The system of claim 16 , wherein when the phase change material melts, the stored thermal energy is depleted and the heat load cooling mode has completed a cycle of operation.

18. The system of claim 16 , further comprising an ejector comprising a primary inlet, a secondary inlet, and an outlet fluidly coupled to the evaporator inlet.

19. The system of claim 1 , wherein the VCS is configured, with the compressor in an off state, to increase a refrigerant pressure to turn the refrigerant fluid that is in a saturated refrigerant liquid thermodynamic state in the liquid separator into a subcooled state, and the pump is configured to circulate the subcooled refrigerant liquid through the evaporator to cause at least partial evaporation of the refrigerant liquid into refrigerant vapor that is transported to the TES to be condensed and subcooled.

20. The system of claim 19 , wherein the compressor is configured to increase a cooling capacity of the VCS in an on state.

21. The system of claim 19 , wherein the VCS is configured to return the subcooled refrigerant liquid to the liquid separator, and to complete a cycle of the heat load cooling mode by melting the phase change material and depleting the stored thermal energy.

22. The system of claim 21 , wherein the refrigerant comprises ammonia or carbon dioxide.

23. The system of claim 1 , further comprising:
an open-circuit refrigerant system (OCRS) comprising the receiver, the expansion valve, the TES, the evaporator, and the liquid separator, with the expansion valve configured to control vapor quality of refrigerant fluid at the outlet of the evaporator, the OCRS further comprising:
an exhaust line; and
a back-pressure regulator comprising an inlet coupled to the VCS and comprising an outlet coupled to the exhaust line, with the back-pressure regulator configured to control a temperature of the heat loa

Assignees

• Booz Allen Hamilton Inc

Inventors

• Vaisman Igor
• Peters Joshua

Classifications

• F25B9/008

  the refrigerant being carbon dioxide · CPC title

• F25B41/20 Primary

  Disposition of valves, e.g. of on-off valves or flow control valves (expansion valves F25B41/31) · CPC title

• F25B41/31

  Expansion valves · CPC title

• F25B2400/16

  Receivers · CPC title

• Y02E60/14

  Thermal energy storage · CPC title