Thermosyphon coolers for cooling systems with cooling towers

Patent metadata

Field	Value
Publication number	US-9939201-B2
Application number	US-201615231545-A
Country	US
Kind code	B2
Filing date	Aug 8, 2016
Priority date	May 27, 2010
Publication date	Apr 10, 2018
Grant date	Apr 10, 2018

Abstract

In one embodiment, a cooling system may include a thermosyphon cooler that cools a cooling fluid through dry cooling and a cooling tower that cools a cooling fluid through evaporative cooling. The thermosyphon cooler may use natural convection to circulate a refrigerant between a shell and tube evaporator and an air cooled condenser. The thermosyphon cooler may be located in the cooling system upstream of, and in series with, the cooling tower, and may be operated when the thermosyphon cooler is more economically and/or resource efficient to operate than the cooling tower. According to certain embodiments, factors, such as the ambient temperature, the cost of electricity, and the cost of water, among others, may be used to determine whether to operate the thermosyphon cooler, the cooling tower, or both.

First claim

The invention claimed is:

1. A cooling system, comprising:
a cooling fluid loop configured to cycle a cooling fluid therethrough;
a thermosyphon cooler in direct thermal communication with the cooling fluid loop, wherein the thermosyphon cooler is configured to transfer heat from the cooling fluid to a refrigerant in an evaporator of the thermosyphon cooler to evaporate the refrigerant into refrigerant vapor, wherein the thermosyphon cooler is configured to transfer heat from the refrigerant vapor to ambient atmosphere through dry cooling in a condenser of the thermosyphon cooler to condense the refrigerant vapor into refrigerant liquid, and wherein the thermosyhpon cooler is configured to circulate the refrigerant through the evaporator and the condenser without mechanical force;
a cooling tower in direct thermal communication with the cooling fluid loop and downstream of the thermosyphon cooler with respect to a flow of the cooling fluid through the cooling fluid loop wherein the cooling tower is configured to transfer heat from the cooling fluid to the ambient atmosphere through evaporative cooling;
a pressure sensor configured to measure a pressure of the refrigerant in the evaporator of the thermosyphon cooler;
a first valve of the thermosyphon cooler configured to block a flow of the refrigerant to the evaporator when in a closed position; and
a controller configured to control operation of the thermosyphon cooler based at least on measures of water cost, electricity cost, or a combination thereof, wherein the controller is configured to adjust a position of the first valve of the thermosyphon cooler based at least on the pressure of the refrigerant in the evaporator of the thermosyphon cooler provided by the pressure sensor, wherein the controller is configured to adjust the first valve to the closed position in response to the pressure of the refrigerant in the evaporator being less than a first pressure threshold, wherein the controller is configured to block a flow of the cooling fluid through the evaporator of the thermosyphon cooler in response to the pressure of the refrigerant in the evaporator being less than a second pressure threshold, wherein the second pressure threshold is less than the first pressure threshold, wherein when the pressure is less than the second pressure threshold the controller is configured to block the flow of the cooling fluid through the evaporator by closing a second valve of the cooling fluid loop or adjusting a speed of a pump of the cooling fluid loop, and wherein the evaporator of the thermosyphon cooler comprises heat tracing, or cartridge heaters, or both, and wherein the controller is configured to activate the heat tracing, or the cartridge heaters, or both, when the pressure of the refrigerant in the evaporator is less than the second pressure threshold.

2. The system of claim 1 , wherein the controller is configured to deactivate the heat tracing, or the cartridge heaters, or both when the pressure of the refrigerant in the evaporator exceeds a third pressure threshold, and wherein the third pressure threshold is greater than the second pressure threshold and less than the first pressure threshold.

3. The system of claim 2 , wherein the controller is configured to adjust the first valve from the closed position to an open position when the pressure of the refrigerant in the evaporator exceeds a fourth pressure threshold, and wherein the fourth pressure threshold is greater than the third pressure threshold and the first pressure threshold.

4. The system of claim 1 , wherein the thermosyphon cooler comprises a drain valve, and wherein the controller is configured to open the drain valve when the pressure of the refrigerant in the evaporator falls below a third pressure threshold, wherein the third pressure threshold is less than the second pressure threshold.

5. The system of claim 1 , wherein the controller is configured to determine the flow of the cooling fluid through the evaporator of the thermosyphon cooler based on a pressure differential of the cooling fluid flowing through the evaporator of the thermosyphon cooler, and wherein the controller is configured to initiate a low temperature protection mode when the controller determines that there is no flow of the cooling fluid through the thermosyphon cooler and the pressure of the refrigerant in the evaporator is below the second pressure threshold.

6. The system of claim 5 , wherein the controller activates the heat tracing, or the cartridge heaters, or both in the evaporator in the low temperature protection mode.

7. The system of claim 1 , comprising a temperature sensor configured to measure a temperature of the ambient atmosphere, wherein the temperature sensor is configured to provide feedback to the controller indicative of the temperature of the ambient atmosphere.

8. The system of claim 7 , wherein the controller is configured to adjust the first valve to the closed position when the temperature of the ambient atmosphere is below a threshold temperature.

9. A system, comprising:
a thermosyphon cooler disposed along a cooling fluid loop upstream of a cooling tower;
an evaporator of the thermosyphon cooler configured to transfer heat from a cooling fluid of the cooling fluid loop to a refrigerant of the thermosyphon cooler to evaporate the refrigerant into a refrigerant vapor;
a condenser of the thermosyphon cooler configured to transfer heat from the refrigerant vapor to ambient atmosphere through dry cooling to condense the refrigerant vapor into refrigerant liquid, wherein the thermosyphon cooler is configured to direct the refrigerant from the evaporator to the condenser via natural convection, and wherein the thermosyphon cooler is configured to direct the refrigerant from the condenser to the evaporator via gravitational force; and
one or more tangible, non-transitory machine readable media comprising processor executable instructions to:
receive feedback from a pressure sensor configured to measure a pressure of the refrigerant in the evaporator of the thermosyphon cooler;
compare the pressure of the refrigerant flowing through the evaporator of the thermosyphon cooler to a first pressure threshold;
close a first valve of the thermosyphon cooler to block the refrigerant of the thermosyphon cooler from flowing to the evaporator when the pressure of the refrigerant in the evaporator of the thermosyphon cooler is below the first pressure threshold;
compare the pressure of the refrigerant in the evaporator of the thermosyphon cooler to a second pressure threshold, wherein the second pressure threshold is less than the first pressure threshold;
close a second valve of the cooling fluid loop to block the cooling fluid from flowing through the evaporator of the thermosyphon cooler when the pressure of the refrigerant in the evaporator of the thermosyphon cooler is below the second pressure threshold; and
activate heat tracing, or cartridge heaters, or both of the evaporator of the thermosyphon cooler when the pressure of the refrigerant in the evaporator of the thermosyphon cooler is below the second pressure threshold.

10. The system of claim 9 , wherein the second valve of the cooling fluid loop is configured to direct the cooling fluid to the cooling tower such that the cooling fluid bypasses the thermosyphon cooler.

11. The system of claim 9 , wherein the processor-executable instructions:
deactivate the heat tracing, or the cartridge heaters, or both when the pressure of the refrigerant in the evaporator of the thermosyphon cooler exceeds a third pressure threshold, wherein the third pressure threshold is greater than the second pressure threshold and is less than the first pre

Assignees

• Johnson Controls Tech Co

Inventors

• Furlong James W
• Pillis Joseph W
• Lehman Delmar E

Classifications

• F28F27/003

  specially adapted for cooling towers · CPC title

• F28D7/103

  consisting of more than two coaxial conduits or modules of more than two coaxial conduits · CPC title

• F28C1/00 Primary

  Direct-contact trickle coolers, e.g. cooling towers (building construction E04H5/12; enclosed spaces cooled by trickle F25; components parts of trickle coolers F28F25/00; {indirect-contact cooling towers F28B1/06}) · CPC title

• F28C2001/006

  Systems comprising cooling towers, e.g. for recooling a cooling medium · CPC title

• F28B1/06 Primary

  using air or other gas as the cooling medium · CPC title