Phase-change cooling of subterranean power lines

Patent metadata

Field	Value
Publication number	US-9562704-B2
Application number	US-201514861766-A
Country	US
Kind code	B2
Filing date	Sep 22, 2015
Priority date	Jul 18, 2012
Publication date	Feb 7, 2017
Grant date	Feb 7, 2017

Abstract

A cooling system for a subterranean power line may include a cooling tube configured to house a fluid. Heat generated by the subterranean power line may be radiated and/or conducted to the cooling tube and absorbed by the fluid within the cooling tube. As the fluid heats up, it may change phase from a liquid to a gas. The hot gas may rise to a heat-exchanging condenser configured to dissipate the heat and condense the fluid back into a liquid. The cool, condensed liquid my return from the heat-exchanging condenser to the cooling tube. Risers, gas transport tubes, pressure regulation systems, fluid storage tanks, and other components described herein may increase the efficiency of the cooling system and/or otherwise improve the viability of the cooling system for subterranean power lines.

First claim

What is claimed is:

1. A method of cooling a subterranean power line comprising:
receiving, via a cooling tube, thermal energy generated by a current flow through at least one subterranean power line, wherein the subterranean power line is located external to the cooling tube;
absorbing, via a fluid within the cooling tube, at least some of the thermal energy received by the cooling tube;
receiving, via a heat-exchanging condenser fluidly connected to the cooling tube, the fluid in a heated, gaseous phase; and
dissipating, via the heat-exchanging condenser, the thermal energy stored in the fluid.

2. The method of claim 1 , further comprising pressurizing the cooling tube relative to an ambient atmospheric pressure.

3. The method of claim 1 , wherein the cooling tube and fluidly connected components are fluidly sealed.

4. The method of claim 3 , wherein the pressure within the cooling tube is configured to be adjusted based on an electrical current flow associated with the at least one power line.

5. The method of claim 3 , wherein the pressure within the cooling tube is configured to be adjusted based on a power dissipation associated with the at least one power line.

6. The method of claim 1 , wherein the fluid comprises water.

7. The method of claim 1 , wherein the fluid comprises an alcohol.

8. The method of claim 1 , wherein the fluid in a liquid phase is transported within the cooling tube via surface tension forces.

9. The method of claim 1 , wherein the at least one power line comprises at least two power lines, and wherein the cooling tube is configured to dissipate thermal energy generated by each of the at least two power lines.

10. The method of claim 1 , wherein dissipating, via the heat exchanging condenser, the thermal energy stored in the fluid comprises:
receiving the fluid in a heated, gaseous phase;
dissipating thermal energy stored in the fluid in the gaseous phase; and
returning the fluid in a cooled, liquid phase.

11. A power line cooling system, comprising:
a cooling tube configured to be positioned proximate at least a portion of at least one external power line, such that the power line is external to the cooling tube;
a fluid within the cooling tube, the fluid configured to absorb thermal energy generated by a current flow through the at least one power line; and
a heat-exchanging condenser fluidly connected to the cooling tube, the heat-exchanging condenser configured to:
receive the fluid in a heated, gaseous phase, and
dissipate thermal energy stored in the fluid in the gaseous phase.

12. The power line cooling system of claim 11 , wherein the cooling tube is configured to be positioned with a gap between at least one of the at least one external power line and the cooling tube.

13. The power line cooling system of claim 11 , wherein the fluid is sealed within the cooling tube.

14. The power line cooling system of claim 13 , wherein the cooling tub is configured to be depressurized to a pressure below an ambient, external pressure.

15. The power line cooling system of claim 11 , further comprising a riser fluidly connecting the heat-exchanging condenser to the cooling tube,
wherein the first end of the riser is fluidly connected to the cooling tube and the second end of the riser is fluidly connected to the heat-exchanging condenser.

16. The power line cooling system of claim 11 , further comprising:
a gas transport tube configured to be positioned at a higher elevation than the cooling tube; and
at least one riser configured to fluidly connect the cooling tube to the gas transport tube, and
wherein the heat-exchanging condenser is configured to be fluidly connected to the gas transport tube, such that the heat-exchanging condenser is fluidly connected to the cooling tube through the gas transport tube and the at least one riser.

17. The power line cooling system of claim 16 , wherein at least a portion of the cooling tube, the gas transport tube, and the at least one riser comprises a metal.

18. The power line cooling system of claim 11 , wherein the pressure within the cooling tube is configured to be adjusted based on a temperature of a ground material surrounding the cooling tube.

19. The power line cooling system of claim 11 , further comprising a condenser riser fluidly connecting the heat-exchanging condenser to a gas transport tube,
wherein a first end of the condenser riser is configured to be installed at a lower elevation than a second end of the condenser riser, and
wherein the first end of the condenser riser is configured to be fluidly connected to the gas transport tube and the second end of the condenser riser is configured to be fluidly connected to the heat-exchanging condenser.

20. The power line cooling system of claim 11 , wherein the fluid in a liquid phase is configured to return from the heat-exchanging condenser to the cooling tube via a return tube.

21. A method of cooling a subterranean power line comprising:
receiving, via a cooling tube, thermal energy generated by a current flow through at least one subterranean power line located external to the cooling tube;
depressurizing the cooling tube to an adjustable pressure value relative to an ambient external pressure;
absorbing, via a fluid within the cooling tube, at least some of the thermal energy received by the cooling tube;
receiving, via a heat-exchanging condenser fluidly connected to the cooling tube, the fluid in a heated, gaseous phase;
dissipating, via the heat-exchanging condenser, the thermal energy stored in the fluid;
receiving the fluid in a cooled, liquid phase; and
adjusting the pressure within the cooling tube based on a monitored external condition.

22. The method of claim 21 , wherein the fluid is a solid at standard ambient temperature and pressure (SATP), and
wherein the pressure within the cooling tube is reduced such that the solid changes phase to a liquid at approximately the standard temperature at the pressure adjusted based on the monitored external condition.

23. The method of claim 21 , wherein adjusting the pressure within the cooling tube is done in response to a combination of a plurality of measured external conditions.

24. The method of claim 21 , wherein the measured external condition comprises a condensation temperate associated with the heat-exchanging condenser.

25. The method of claim 21 , wherein adjusting the pressure within the cooling tube is based at least in part on the amount of current carried in the at least one power line.

26. The method of claim 21 , wherein adjusting the pressure within the cooling tube is based at least in part on one or more of a season, a ground temperature, a measured current flow through the power, and an ambient temperature external to the cooling tube.

27. The method of claim 21 , wherein adjusting the pressure within the cooling tube is based at least in part on the time of day.

28. A power line cooling system, comprising:
a cooling tube configured to be positioned proximate at least a portion of at least one external power line, such that the power line is external to the cooling tube;
a fluid within the cooling tube, the fluid configured to absorb thermal energy generated by an electrical current flow through the at least one power line;
a heat-exchanging condenser fluidly connected to the cooling tube, the heat-exchanging condenser

Assignees

• Elwha Llc

Inventors

• Hyde Roderick A
• Kare Jordin T
• Myhrvold Nathan P
• Tuckerman David B
• Wood Jr Lowell L

Classifications

• H02G9/02

  laid directly in or on the ground, river-bed or sea-bottom; Coverings therefor, e.g. tile · CPC title

• F28D2021/0028

  for cooling heat generating elements, e.g. for cooling electronic components or electric devices · CPC title

• F28D15/02

  in which the medium condenses and evaporates, e.g. heat pipes {(heat pipes used in solar heat collectors F24S10/95; in radiators F28D1/0226; in nuclear reactors G21C15/257)} · CPC title

• F24J3/08 Primary

  Mechanical Engineering · mapped topic

• Y02E10/10

  Geothermal energy · CPC title