Thermal management systems for extended operation

Patent metadata

Field	Value
Publication number	US-11781817-B2
Application number	US-202217846886-A
Country	US
Kind code	B2
Filing date	Jun 22, 2022
Priority date	Jun 22, 2021
Publication date	Oct 10, 2023
Grant date	Oct 10, 2023

Abstract

A thermal management system includes a closed-circuit refrigeration system that includes a vapor cycle system (VCS) and a liquid pumping system (LPS). The VCS includes a receiver that stores a refrigerant fluid and a liquid separator. The vapor cycle system is configured to operate in one or more operational modes including at least one of a TES cooling mode, a heat load cooling mode, or a pump-down mode. The LPS includes a thermal energy storage (TES) that stores a phase change material (PCM) and a pump fluidly coupled to at least one evaporator. The evaporator is configured to extract heat from a heat load that is in thermal conductive or convective contact to the evaporator to transfer heat to the refrigerant fluid and provide the refrigerant fluid from an evaporator outlet to the TES.

First claim

What is claimed is:

1. A thermal management system, comprising:
a closed-circuit refrigeration system, comprising:
a vapor cycle system (VCS), comprising:
a receiver that stores a refrigerant fluid; and a liquid separator comprising a liquid-separator inlet, a liquid-side outlet, and a vapor side outlet, the vapor cycle system configured to operate in one or more operational modes comprising at least one of a TES cooling mode, a heat load cooling mode, or a pump-down mode; and

a liquid pumping system (LPS), comprising:
a thermal energy storage (TES) that stores a phase change material (PCM), the TES comprising a TES inlet and a TES outlet fluidly coupled to the liquid separator inlet;
a pump comprising a pump inlet and a pump outlet; and
at least one evaporator comprising an evaporator inlet coupled to the TES outlet with the TES inlet coupled to the pump outlet, the at least one evaporator configured to extract heat from a heat load that is in thermal conductive or convective contact or in proximity to the at least one evaporator to transfer heat from the heat load to the refrigerant fluid and provide the refrigerant fluid from an evaporator outlet that is coupled to the liquid-separator inlet to the TES inlet, the LPS configured to operate in the heat load cooling mode.

2. The system of claim 1 , wherein the VCS further comprises an expansion valve, a compressor, and a heat rejection heat exchanger.

3. The system of claim 2 , wherein the expansion valve is configured to control a vapor quality of the refrigerant fluid at the evaporator outlet.

4. The system of claim 1 , wherein the TES comprises a heat exchanger that provides thermal contact between the PCM and the refrigerant fluid.

5. The system of claim 4 , wherein in the TES cooling mode, the VCS is configured to charge the PCM in the TES by directing the refrigerant fluid from the receiver through the liquid separator and through the pump and the at least one evaporator to the TES to cause cooling energy from the refrigerant fluid to be stored in the PCM in latent heat form.

6. The system of claim 2 , wherein the VCS operates according to a transcritical refrigeration cycle or a subcritical refrigeration cycle.

7. The system of claim 6 , wherein the VCS is configured to operate in the transcritical refrigeration cycle, and the heat rejection heat exchanger 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, with the refrigerant vapor at the high pressure and temperature being cooled in the gas cooler.

8. The system of claim 6 , wherein the VCS is configured to operate in the subcritical refrigeration cycle, and the heat rejection heat exchanger operates as a condenser, with the refrigerant vapor in the condenser being de-superheated, condensed, and subcooled.

9. The system of claim 2 , wherein in the heat load cooling mode, the VCS is configured to cool the heat load.

10. The system of claim 9 , wherein liquid refrigerant from the receiver is iso-enthalpically expanded in the expansion valve to a low-pressure two-phase mixture of a refrigerant liquid phase and a refrigerant vapor phase.

11. The system of claim 10 , wherein a portion of the refrigerant liquid phase boils out to cool or freeze the PCM in the TES, with any non-evaporated refrigerant liquid being captured by the liquid separator.

12. The system of claim 9 , wherein the LPS is configured to cool the heat load by discharging the stored cooling energy from the PCM in the heat load cooling mode based on operation of the heat load.

13. The system of claim 1 , wherein the LPS is configured to evaporate the refrigerant fluid at a temperature in a range that is below the heat load temperature low limit in order to satisfy heat load temperature tolerances and at the heat transfer rate generated by a temperature differential, and above a PCM freezing temperature to enable operation of the TES as a condenser.

14. The system of claim 2 , wherein the heat load cooling mode starts either while the compressor is in an off state or while the compressor is in an on state.

15. The system of claim 14 , wherein when the compressor is in the off state, the VCS is configured to operate to increase a refrigerant pressure of the refrigerant fluid to turn the refrigerant fluid that is in a saturated refrigerant liquid thermodynamic state in the liquid separator into a subcooled state.

16. The system of claim 15 , wherein the pump is configured to circulate the subcooled refrigerant liquid from the liquid-side outlet through the at least one evaporator to cause complete or partial evaporation of the refrigerant liquid, with refrigerant vapor formed in the at least one evaporator being transported to the TES for cooling.

17. The system of claim 15 , wherein when the PCM has melted and the stored thermal energy is depleted, the heat load cooling mode has completed a cycle of operation.

18. The system of claim 14 , wherein when the compressor is in the on state, the compressor operation increases system cooling capacity or extends the cooling period.

19. The system of claim 18 , wherein when the refrigerant fluid is pumped into the at least one evaporator, the heat load generates refrigerant vapor and an evaporating pressure in the evaporator rises, increasing the pressure in the liquid separator, and a refrigerant liquid thermodynamic state becomes subcooled, and with the engaged pump pumping the subcooled refrigerant liquid from a liquid-side outlet of the liquid separator through the at least one evaporator causing complete or partial evaporation of the subcooled refrigerant liquid, with the refrigerant vapor that results from operation of the heat load in contact with or proximate to the at least one evaporator is condensed and subcooled in the TES.

20. The system of claim 19 , wherein the VCS is configured to return the subcooled refrigerant liquid from the receiver to the liquid-separator inlet.

21. The system of claim 20 , further comprising a back- pressure regulator and wherein in the pump-down mode the heat load is off and the pump is off, the back-pressure regulating valve is closed and the compressor is on.

22. The system of claim 21 , wherein in the pump-down mode, the compressor is configured to receive refrigerant vapor from the liquid separator, compress the refrigerant vapor, and cause the compressed refrigerant vapor to be condensed in the heat rejection heat exchanger, and with the heat rejection exchanger returning the condensed refrigerant vapor to the receiver.

23. The system of claim 22 , wherein during compressor operation, the pressure in the liquid separator is reduced, the evaporating temperature is reduced, and refrigerant fluid evaporates to generate refrigerant vapor for the compressor to compress.

24. The system of claim 2 , further comprising:
an open-circuit refrigerant system comprising the receiver, the expansion valve, the TES, the at least one evaporator, the liquid separator, and the open-circuit refrigerant system further comprising:
an exhaust; and
a back-pressure regulating valve configured to control a temperature of the heat load.

25. The system of claim 24 , wherein the expansion valve is configured to control a vapor quality of the refrigerant fluid at the at least one evaporator, while avoidin

Assignees

• Booz Allen Hamilton Inc

Inventors

• Vaisman Igor
• Peters Joshua

Classifications

• F28D20/021 Primary

  the latent heat storage material and the heat-exchanging means being enclosed in one container (F28D20/023 - F28D20/028 take precedence) · CPC title

• F25B5/04

  arranged in series · CPC title

• F25B9/008

  the refrigerant being carbon dioxide · CPC title

• F25B19/005

  the refrigerant being a liquefied gas · CPC title

• F25B39/00

  Evaporators; Condensers · CPC title