US20090101311A1

US20090101311A1 - System and Method for Cooling Using Two Separate Coolants

Info

Publication number: US20090101311A1
Application number: US11/876,301
Authority: US
Inventors: Richard M. Weber; William G. Wyatt; Kerrin A. Rummel
Original assignee: Raytheon Co
Current assignee: Raytheon Co
Priority date: 2007-10-22
Filing date: 2007-10-22
Publication date: 2009-04-23
Also published as: WO2009055141A1; EP2201312A1

Abstract

According to one embodiment, a cooling system for a heat-generating structure includes a first cooling loop that directs a flow of a first fluid coolant from a heat-generating structure to a first heat exchanger. The system also includes a second cooling loop that directs a flow of a second fluid coolant from the first heat exchanger to a second heat exchanger. The first heat exchanger receives thermal energy from the first fluid coolant and transfers at least a portion of the thermal energy to the second fluid coolant. The first fluid coolant has a specific heat and a mass flow rate, and the second fluid coolant has a specific heat and a mass flow rate. A product of the specific heat and the mass flow rate of the first fluid coolant is greater than a product of the specific heat and the mass flow rate of the second fluid coolant.

Description

TECHNICAL FIELD OF THE DISCLOSURE

This disclosure relates generally to the field of cooling systems and, more particularly, to a system and method for cooling using two separate coolants.

BACKGROUND OF THE DISCLOSURE

A variety of different types of structures can generate heat or thermal energy in operation. To prevent such structures from over heating, a variety of different types of cooling systems may be utilized to dissipate the thermal energy. The type of coolant provided to these cooling systems may, however, be restricted, forcing the cooling system to dissipate thermal energy using a coolant with properties unsuited for efficient thermal energy dissipation.

SUMMARY OF THE DISCLOSURE

According to one embodiment of the disclosure, a cooling system for a heat-generating structure includes a first cooling loop that directs a flow of a first fluid coolant from a heat-generating structure to a first heat exchanger. The system also includes a second cooling loop that directs a flow of a second fluid coolant from the first heat exchanger to a second heat exchanger. The first heat exchanger receives thermal energy from the first fluid coolant and transfers at least a portion of the thermal energy to the second fluid coolant. The first fluid coolant has a specific heat and a mass flow rate, and the second fluid coolant has a specific heat and a mass flow rate. A product of the specific heat and the mass flow rate of the first fluid coolant is greater than a product of the specific heat and the mass flow rate of the second fluid coolant.
Certain embodiments of the disclosure may provide numerous technical advantages. For example, a technical advantage of one embodiment may include the capability to efficiently cool a structure even though the cooling system is provided with an undesirable fluid coolant or a fluid coolant flowing at an undesirable mass flow rate. For instance, one embodiment of the disclosure may allow for efficient cooling of a phased array antenna located on a mast of a ship. Other technical advantages of other embodiments may include the ability to retrofit a current cooling system in order to more efficiently cool a structure. Still yet other technical advantages of other embodiments may include the capability to prevent an accumulation of air in a fluid coolant used to cool a structure.
Although specific advantages have been enumerated above, various embodiments may include all, some, or none of the enumerated advantages. Additionally, other technical advantages may become readily apparent to one of ordinary skill in the art after review of the following figures and description.

BRIEF DESCRIPTION OF THE DRAWINGS

For a more complete understanding of example embodiments of the present disclosure and its advantages, reference is now made to the following description, taken in conjunction with the accompanying drawings, in which:

FIG. 1 is a block diagram of an embodiment of a cooling system that may be utilized in conjunction with embodiments of the present disclosure; and

FIG. 2 is a block diagram of a cooling system for cooling a heat-generating structure, according to an embodiments of the disclosure.

DETAILED DESCRIPTION OF EXAMPLE EMBODIMENTS OF THE DISCLOSURE

It should be understood at the outset that although example embodiments of the present disclosure are illustrated below, the present disclosure may be implemented using any number of techniques, whether currently known or in existence. The present disclosure should in no way be limited to the example embodiments, drawings, and techniques illustrated below, including the embodiments and implementation illustrated and described herein. Additionally, the drawings are not necessarily drawn to scale.
Conventionally, cooling systems may be used to cool commercial and military applications. Although these cooling systems may minimize a need for conditioned air, they may be limited by their location, the type of coolant available, and restrictions on the flow of the available coolant.
FIG. 1 is a block diagram of an embodiment of a cooling system that may be utilized in conjunction with embodiments of the present disclosure. Although the details of one cooling system will be described below, it should be expressly understood that other cooling systems may be used in conjunction with embodiments of the disclosure.
The cooling system 10 of FIG. 1 is shown cooling a structure 12 that is exposed to or generates thermal energy. The structure 12 may be any of a variety of structures, including, but not limited to, electronic components, circuits, computers, servers, and phased array antennas. Because the structure 12 can vary greatly, the details of structure 12 are not illustrated and described. The cooling system 10 of FIG. 1 includes a heat exchanger inlet line 61, a structure inlet line 71, structure heat exchangers 23 and 24, a loop pump 46, inlet orifices 47 and 48, a heat exchanger 41, a reservoir 42, and a pressure controller 51.
The structure 12 may be arranged and designed to conduct heat or thermal energy to the structure heat exchangers 23, 24. To receive this thermal energy or heat, the structure heat exchangers 23, 24 may be disposed on an edge of the structure 12 (e.g., as a thermosyphon, heat pipe, or other device) or may extend through portions of the structure 12, for example, through a thermal plane of the structure 12. In particular embodiments, the structure heat exchangers 23, 24 may extend up to the components of the structure 12, directly receiving thermal energy from the components. Although two structure heat exchangers 23, 24 are shown in the cooling system 10 of FIG. 1, one structure heat exchanger or more than two structure heat exchangers may be used to cool the structure 12 in other cooling systems.
In operation, a fluid coolant flows through each of the structure heat exchangers 23, 24. The fluid coolant absorbs heat from the structure 12. To facilitate such absorption or transfer of thermal energy, the structure heat exchangers 23, 24 may be lined with pin fins or other similar devices which, among other things, increase surface contact between the fluid coolant and walls of the structure heat exchangers 23, 24. Additionally, in particular embodiments, the fluid coolant may be forced or sprayed into the structure heat exchangers 23, 24 to ensure fluid contact between the fluid coolant and the walls of the structure heat exchangers 23, 24. In one embodiment, the fluid coolant may remain in a liquid phase after absorption of heat from the structure 12. In a further embodiment, the absorption of heat from the structure 12 may cause at least a portion of the fluid coolant to vaporize.
The fluid coolant departs the exit conduits 27 and flows through the heat exchanger inlet line 61, the heat exchanger 41, the reservoir 42, a loop pump 46, the structure inlet line 71, and a respective one of two orifices 47 and 48, in order to again reach the inlet conduits 25 of the structure heat exchangers 23, 24. The loop pump 46 may cause the fluid coolant to circulate around the loop shown in FIG. 1. In particular embodiments, the loop pump 46 may use magnetic drives so there are no shaft seals that can wear or leak with time. In one embodiment, the loop pump 46 may control the mass flow rate of the fluid coolant in the loop. For example, the loop pump 46 may increase, decrease, or keep the mass flow rate of the fluid coolant constant.
The orifices 47 and 48, in particular embodiments, may facilitate proper partitioning of the fluid coolant among the respective structure heat exchangers 23, 24, and may also help to create a large pressure drop between the output of the loop pump 46 and the heat exchangers 23, 24. The orifices 47 and 48 may have the same size, or may have different sizes in order to partition the coolant in a proportional manner which facilitates a desired cooling profile.
A flow 56 of fluid (either gas or liquid) may be forced to flow through the heat exchanger 41, for example by a fan (not shown) or other suitable device. In particular embodiments, the flow 56 of fluid may be ambient fluid. The heat exchanger 41 transfers heat from the fluid coolant to the flow 56 of ambient fluid, thereby reducing the temperature of the fluid coolant. In one embodiment, the fluid coolant may be in a liquid phase prior to entering the heat exchanger 41. In this embodiment, the transfer of heat to the flow 56 may not cause the fluid coolant to change phases. In another embodiment, at least a portion of the fluid coolant may be in a vapor phase prior to entering the heat exchanger 41. In such an embodiment, the transfer of heat from the vapor fluid coolant to the flow 56 may farther cause the fluid coolant to condense into a liquid phase.
The fluid coolant exiting the heat exchanger 41 may be supplied to the reservoir 42. In one embodiment, the reservoir 42 may store the fluid coolant when the cooling system 10 is not in operation. In a further embodiment, the reservoir 42 may be an expansion reservoir. Since fluids typically take up more volume in their vapor phase than in their liquid phase, the expansion reservoir may be provided in order to take up the volume of liquid fluid coolant that is displaced when some or all of the coolant in the system changes from its liquid phase to its vapor phase.
The fluid coolant used in the embodiment of FIG. 1 may include, but is not limited to, mixtures of antifreeze and water or water, alone. In particular embodiments, the antifreeze may be ethanol, methanol, or other suitable antifreeze. In other embodiments, the fluid coolant may include polyalphaolefin (PAO), a mixture of water and propylene glycol (PGW), a mixture of water and ethylene glycol (EGW), HFC-134a, Coolanol, ammonia, brine, or any other suitable fluid coolant.
The pressure controller 51 maintains the fluid coolant at a substantially constant pressure along the portion of the loop which extends from the orifices 47 and 48 to the loop pump 46, in particular through the structure heat exchangers 23 and 24, the heat exchanger 41, and the reservoir 42. In particular embodiments, metal bellows may be used in the reservoir 42, connected to the loop using brazed joints. In particular embodiments, the pressure controller 51 may control loop pressure by using a motor driven linear actuator that is part of the metal bellows of the reservoir 42, or by using a small gear pump to evacuate the loop to the desired pressure level. The fluid coolant removed may be stored in the metal bellows whose fluid connects are brazed. In other configurations, the pressure controller 51 may utilize other suitable devices capable of controlling pressure.
It will be noted that the embodiment of FIG. 1 may operate without a refrigeration system. In the context of electronic circuitry, such as may be utilized in the structure 12, the absence of a refrigeration system can result in a significant reduction in the size, weight, and power consumption of the structure provided to cool the circuit components of the structure 12.
In certain embodiments, the ability to cool the structure 12 may depend, at least in part, on the fluid coolant used in cooling system 10. For example, the ability to cool the structure 12 may depend on the heat transfer coefficient of the fluid coolant. A fluid coolant with a high heat transfer coefficient may, in one embodiment, cool the structure 12 more efficiently than a fluid coolant with a low heat transfer coefficient. In certain embodiments, the heat transfer coefficient of a fluid coolant may be a function of the specific heat (C_p) of the fluid coolant and the viscosity of the fluid coolant. Specifically, a fluid coolant with high specific heat may have a higher heat transfer coefficient than a fluid coolant with a low specific heat. Additionally, a fluid coolant with low viscosity may have a higher heat transfer coefficient than a fluid coolant with high viscosity. In another embodiment, the heat transfer coefficient may also be a function of the mass flow rate ({dot over (m)}) of the fluid coolant. For example, a fluid coolant flowing at a high mass flow rate may have a higher heat transfer coefficient than a fluid coolant flowing at a low mass flow rate. As a result, in certain embodiments, a fluid coolant with a high specific heat and low viscosity, and which is flowing at a high mass flow rate, may be more desirable for use in the cooling system 10 because the higher heat transfer coefficient of the fluid coolant may provide more efficient cooling of the structure 12.
As another example, the ability to cool the structure 12 in the cooling system 10 may depend on the structure temperature gradient. The structure temperature gradient, in one embodiment, refers to the difference in the temperature of the fluid coolant entering the structure 12 and the temperature of the fluid coolant exiting the structure 12. In one embodiment, a high structure temperature gradient refers to a large temperature difference between the fluid coolant entering the structure 12 and the fluid coolant exiting the structure 12. In such an embodiment, the high structure temperature gradient may cause elements of the structure 12 to be cooled to different temperatures. For example, elements near the fluid coolant inlet of the structure 12 may be cooled to a lower temperature than the elements near the fluid coolant outlet of the structure 12. As a result, a temperature difference between the elements of the structure 12 may occur.
In certain embodiments, the structure temperature gradient of structure 12 may be reduced by the use of a fluid coolant with a high specific heat. For example, a fluid coolant with a high specific heat may absorb more heat for every degree of temperature increase in the fluid coolant than would a fluid coolant with a low specific heat. In another embodiment, the structure temperature gradient may further be a function of the mass flow rate of the fluid coolant. For example, the structure temperature gradient may further be reduced by increasing the mass flow rate of the fluid coolant. As a result, in certain embodiments, a fluid coolant with a high specific heat, and which is flowing at a high mass flow rate, may be more desirable for use in the cooling system 10 because the reduced structure temperature gradient may provide more efficient cooling of the structure 12.
As discussed above, the ability to cool the structure 12 in the cooling system 10 may depend, at least in part, on the specific heat and viscosity of a fluid coolant. For example, a fluid coolant with a high specific heat and low viscosity may have a higher heat transfer coefficient than a fluid coolant with a low specific heat and high viscosity. Furthermore, a fluid coolant with a high specific heat may also reduce the structure temperature gradient. As a result, in one embodiment, a fluid coolant with a high specific heat and low viscosity may allow for more efficient cooling of the structure 12. Therefore, although many different types of fluid coolants may be used in the cooling system 10, as discussed above, particular fluid coolants may be more desirable in certain embodiments of the cooling system 10. For example, fluid coolants such as PGW, EGW, HFC-134a, ammonia, pure water, a mixture of water and methanol, a mixture of water and ethanol, and brine have a high specific heat and low viscosity, and therefore, may be more desirable as fluid coolants in the cooling system 10. On the other hand, certain types of fluid coolants may be undesirable in the cooling system 10. In particular, fluid coolants such as PAO and Coolanol both have a low specific heat and high viscosity, and therefore, are less desirable as fluid coolants in cooling system 10.
A desirable fluid coolant, however, may be unavailable in certain embodiments. In one embodiment, the structure needing to be cooled may be located in a system where only an undesirable, or less desirable, fluid coolant is available. For example, the structure needing to be cooled, such as a phased array antenna, may be located on the mast of a ship capable of providing only a fluid coolant such as PAO or Coolanol in order to cool the structure. In other embodiments, the structure to be cooled may be located in an aircraft, such as a plane, where only an undesirable fluid coolant is available. Therefore, the cooling system may be forced to use the undesirable fluid coolant. As a result, the ability to cool the structure may be reduced.
As also discussed above, the ability to cool the structure 12 in the cooling system 10 may further depend, at least in part, on the mass flow rate of a fluid coolant. For example, a fluid coolant flowing at a high mass flow rate may have a high heat transfer coefficient and may also have a low structure temperature gradient. As a result, in certain embodiments, it may be desirable to provide a system with a fluid coolant flowing at a high mass flow rate.
Contrary to what may be desirable, in certain embodiments, a cooling system may not be provided with a fluid coolant flowing at a desirable mass flow rate. In one embodiment, the structure to be cooled may be located in a system that can only provide a fluid coolant flowing at an undesirable flow rate. For example, the structure, such as a phased array antenna, may be located on the mast of a ship where the mass flow rate of the fluid coolant may be undesirably reduced by the need to pump the fluid coolant up the mast. In another embodiment, the structure may be located in a system where the mass flow rate of the fluid coolant must be restricted in order to be used in the system. As a result, in certain embodiments, the ability to cool a structure may be reduced.
Conventionally, some of these problems have been addressed by directing the undesirable coolant through a dense fin stock that includes complicated cold plates. In order to do so, the systems using such conventional techniques require counter-flow channels and parallel-flow flow distribution of the fluid coolant. These conventional solutions, however, may be expensive and inefficient, and therefore, may also be undesirable.
Given the above discussion, teachings of certain embodiments of the disclosure recognize a system that may used to retrofit a conventional cooling system in a manner that allows use of a desirable fluid coolant flowing at a desirable mass flow rate.
FIG. 2 is a block diagram of an embodiment of a cooling system 110 for cooling a heat generating structure, according to an embodiment of the disclosure. In the embodiment of FIG. 2, the cooling system 110 includes two separate cooling loops: a structure loop 120 for cooling a structure 112 using a first fluid coolant, and a chiller loop 124 for cooling the first fluid coolant using a second fluid coolant. The cooling system 110 further includes a heat exchanger 141 for transferring heat from the first fluid coolant of the structure loop 120 to the second fluid coolant of the chiller loop 124. In one embodiment, this may prevent the cooling system 110 from having to use an undesirable fluid coolant with an undesirable mass flow rate in order to cool the structure 112. Thus, according to one embodiment, an undesirable fluid coolant with an undesirable mass flow rate is merely used to cool a desirable fluid coolant with a desirable mass flow rate.
The structure loop 120 of the cooling system 110 of FIG. 2 may be similar to the cooling system 10 of FIG. 1 except that the structure loop 120 dispenser thermal energy to a chiller loop 124, which has a chiller 138. For simplicity of FIG. 2, the structure loop 120 of FIG. 2 is depicted as being less detailed than cooling system 10 of FIG. 1. However, in certain embodiments, the cooling system 110 (the structure loop 120 ) of FIG. 2 may contain each of the elements of cooling system 10, less elements than cooling system 10, or more elements than cooling system 10.
The structure loop 120 direct a first fluid coolant through the structure 112, a heat exchanger inlet line 161, the heat exchanger 141, a reservoir 142, a pump 146, and a structure inlet line 171, in order to again reach the structure 112. In one embodiment, the structure loop 120 is further operable to keep the first fluid coolant of the structure loop 120 separate from the second fluid coolant of the chiller loop 124.
The chiller loop 124 directs the second fluid coolant from the heat exchanger 141 through line 158, chiller 138, and line 159 in order to again reach the heat exchanger 141. In one embodiment, the chiller loop 124 (and lines 158, 159) may extend a large distance. For example, the chiller loop 124 may extend from a heat exchanger on a mast of a ship to a chiller located at any other position on the ship.
In particular embodiment, the chiller loop 120 may be a new chiller loop added to the system where the structure 112 is located. For example, the chiller loop 120 may be added to the system when the structure 112, the heat exchanger 141, and the structure loop 120 are added to the system. In other embodiments, the chiller loop 124 may be a pre-existing chiller loop that is already used in the system where the structure is located. For example, the chiller loop 124 may be a pre-existing chiller loop used to absorb heat from other components of a ship or aircraft. In such an embodiment, the chiller loop 124 may be retrofitted in order to work in conjunction with the heat exchanger 141 and the structure loop 120.
In a further embodiment, the chiller loop 124 may include a pump (not shown) operable to cause the second fluid coolant to flow throughout the chiller loop 124. The pump, in one embodiment, may be incapable of preventing air from accumulating in the chiller loop 124 while the chiller loop 124 is not in use. For example, the pump may be a component of a pre-existing and out-dated chiller loop system. In such an embodiment, the air accumulation may not have an adverse effect on the cooling of the structure 112 because the chiller loop 124 may be further operable to keep the second fluid coolant (which may include the accumulated air) of the chiller loop 124 separate from the first fluid coolant of the structure loop 120.
The first fluid coolant of the structure loop 120 may include any fluid coolant with a high specific heat and low viscosity. For example, the first fluid coolant may include PGW, EGW, HFC-134a, ammonia, pure water, a mixture of water and methanol, a mixture of ethanol and water, brine, or any other suitable fluid coolant with a high specific heat and low viscosity. In another embodiment, the first fluid coolant may include a fluid coolant with either a high specific heat or low viscosity, but not both. In another embodiment, the first fluid coolant may flow at a high mass flow rate. For example, the pump 146 may cause the first fluid coolant to flow at a higher mass flow rate than would be capable without the two separate loops. In such an embodiment, the higher mass flow rate may increase the ability to cool the structure 112 without using a desirable fluid coolant. As a result, in one embodiment, the first fluid coolant may be the same type of fluid coolant as the second fluid coolant of the chiller loop 124.
In certain embodiments, the first fluid coolant may further include any fluid coolant that has a higher specific heat than that of the second fluid coolant, or that is flowing at a higher mass flow rate than that of the second fluid coolant. For example, the first fluid coolant may include any fluid coolant that satisfies the following inequality:
{dot over (m)}₁C_P1>{dot over (m)}₂C_P2
{dot over (m)}₁=mass flow rate of the first fluid coolant
C_P1=specific heat of the first fluid coolant
{dot over (m)}₂=mass flow rate of the second fluid coolant
C_P2=specific heat of the second fluid coolant
In one embodiment, a first fluid coolant that satisfies the above inequality may provide more efficient cooling of the structure 112 than the second fluid coolant. In a further embodiment, the viscosity of both the first fluid coolant and the second fluid coolant may also be a factor of the above inequality. For example, the inverse of the viscosity of the first fluid coolant and the inverse of the viscosity of the second fluid coolant may be factors of the above inequality. As a result, the first fluid coolant may include a fluid coolant that is merely less viscous than the second fluid coolant.
The second fluid coolant of the chiller loop 124, on the other hand, may include any fluid coolant with either a low specific heat or high viscosity, or both. For example, the second fluid coolant may include PAO or Coolanol. In another embodiment, the second fluid coolant may flow at a low mass flow rate. In such an embodiment, the second fluid coolant may include a fluid coolant with a high specific heat or low viscosity, or both. For example, the second fluid coolant may include PGW or EGW, but may flow at a low mass flow rate. In certain embodiments, the second fluid coolant may further include any fluid coolant that satisfies the inequality discussed above.
The chiller 138 may include any system operable to cool the second fluid coolant of the chiller loop 124. For example, the chiller 138 may include a refrigeration system or a heat exchanger. In another embodiment, the chiller 138 may be operable to cool a fluid coolant used to cool more than the first fluid coolant of the structure loop 120. For example, the second fluid coolant cooled by chiller 138 may further be used to cool other systems, such as other components of a ship or an aircraft.
In operation, the cooling of the structure 112 is substantially similar to the cooling of the structure 12 described in FIG. 1. For example, the first fluid coolant of the structure loop 120 flows through each of the structure heat exchangers 123, 124 (not shown), absorbing heat from the structure 112. The first fluid coolant departs the exit conduits 127 (not shown) and flows through the heat exchanger inlet line 161 and the heat exchanger 141.
At the heat exchanger 141, a flow 156 may be forced to flow through the heat exchanger 141 in order to absorb heat from the first fluid coolant. The flow 156 is similar to the flow 56 of FIG. 1 except that it includes the second fluid coolant of the chiller loop 124. As a result, the heat exchanger 141 transfers heat from the first fluid coolant to the second fluid coolant, thereby reducing the temperature of the first fluid coolant.
After the heat exchanger 141 transfers heat from the first fluid coolant, the first fluid coolant departs the heat exchanger 141 and flows through the reservoir 142, the loop pump 146, the structure inlet line 171, and a respective one of two orifices 147 and 148 (not shown), in order to again reach the structure heat exchangers 123, 124 (not shown). The loop pump 146 may cause the fluid coolant to circulate around the structure loop 120. In one embodiment, the loop pump 146 may control the mass flow rate of the first fluid coolant in the structure loop 120. For example, the loop pump 146 may increase, decrease, or keep the mass flow rate of the first fluid coolant constant. In particular embodiments, the loop pump 146 may allow the first fluid coolant of the structure loop 120 to flow at a higher mass flow rate than the second fluid coolant of the chiller loop 124. In a further embodiment, the loop pump 146 may be operable to prevent air from accumulating in the structure loop 120 while the structure loop 120 and/or the structure 112 are not in operation. In one embodiment, this may prevent the structure loop 120 from having to undergo air purging routines upon start-up.
As for the chilling loop 124, after the second fluid coolant absorbs heat from the first fluid coolant, the second fluid coolant departs the heat exchanger 141 and flows to the chiller 138. After the chiller 138 removes heat from the second fluid coolant, the second fluid coolant is then directed back to the heat exchanger 141 by the chiller loop 124. Thus, the second fluid coolant, which is less desirable for cooling than the first fluid coolant, absorbs heat from the first fluid coolant. This allows, in one embodiment, the first fluid coolant, which is more desirable for cooling than the second fluid coolant, to absorb heat from the structure 112. As a result, a structure, such as a phased array antenna located on a mast of a ship, may be efficiently cooled even when the cooling system is provided with an undesirable fluid coolant.
Although the present disclosure has been described with several embodiments, a myriad of changes, variations, alterations, transformations, and modifications may be suggested to one skilled in the art, and it is intended that the present disclosure encompass such changes, variations, alterations, transformation, and modifications as they fall within the scope of the appended claims.

Claims

1. A cooling system for a heat-generating structure comprising:

a first cooling loop that directs a flow of a first fluid coolant from a heat-generating structure to a first heat exchanger;

a second cooling loop that directs a flow of a second fluid coolant from the first heat exchanger to a second heat exchanger, the first heat exchanger receiving thermal energy from the first fluid coolant and transferring at least a portion of the thermal energy to the second fluid coolant;

the first heat exchanger receiving the first fluid coolant at a first temperature and dispensing of the first fluid coolant out of the first heat exchanger at a second temperature, the first heat exchanger further receiving the second fluid coolant at a third temperature and dispensing of the second fluid coolant out of the heat exchanger at a fourth temperature, the first temperature of the first fluid coolant being higher than the second temperature of the first fluid coolant, and the third temperature of the second fluid coolant being lower than the fourth temperature of the second fluid coolant;

wherein the first heat exchanger prevents fluid contact between the first fluid coolant and the second fluid coolant; and

wherein the first fluid coolant has a specific heat and a mass flow rate, and the second fluid coolant has a specific heat and a mass flow rate, a product of the specific heat and the mass flow rate of the first fluid coolant being greater than a product of the specific heat and the mass flow rate of the second fluid coolant.

2. The system of claim 1, wherein the heat-generating structure is a phased array antenna located on a mast of a ship.

3. The system of claim 2, wherein the second heat exchanger is a chiller operable to cool the second fluid coolant, the chiller being located remotely from the heat-generating structure, the heat exchanger, and the mast of the ship.

4. The system of claim 3, wherein the first fluid coolant is a mixture of water and propylene glycol (PGW).

5. A cooling system for a heat-generating structure comprising:

a second cooling loop that directs a flow of a second fluid coolant from the first heat exchanger to a second heat exchanger, the first heat exchanger receiving thermal energy from the first fluid coolant and transferring at least a portion of the thermal energy to the second fluid coolant; and

6. The system of claim 5, wherein the heat-generating structure is a phased array antenna.

7. The system of claim 5, wherein the second heat exchanger is a chiller operable to cool the second fluid coolant, the chiller being located remotely from the heat-generating structure and the first heat exchanger.

8. The system of claim 5, wherein the first fluid coolant is a mixture of water and propylene glycol (PGW).

9. The system of claim 5, wherein a product of the specific heat and the mass flow rate of the first fluid coolant being greater than a product of the specific heat and the mass flow rate of the second fluid coolant includes a product of the specific heat, the mass flow rate, and an inverse of a viscosity of the first fluid coolant being greater than a product of the specific heat, mass flow rate, and an inverse of a viscosity of the second fluid coolant.

10. The system of claim 9, wherein the viscosity of the first fluid coolant is lower than the viscosity of the second fluid coolant.

11. The system of claim 5, wherein the specific heat of the first fluid coolant is higher than the specific heat of the second fluid coolant.

12. The system of claim 5, wherein the mass flow rate of the first fluid coolant is higher than the mass flow rate of the second fluid coolant.

13. The system of claim 5, wherein the first fluid coolant includes a fluid coolant selected from a group consisting of a mixture of water and propylene glycol (PGW), a mixture of water and ethylene glycol (EGW), and HFC-134a.

14. The system of claim 5, wherein the second fluid coolant includes a fluid coolant selected from a group consisting of polyalphaolefin (PAO) and Coolanol.

15. The system of claim 12, wherein the second fluid coolant includes a fluid coolant selected from a group consisting of a mixture of water and propylene glycol (PGW) and a mixture of water and ethylene glycol (EGW).

16. The system of claim 5, wherein the first cooling loop is separate from the second cooling loop, and wherein the first and second cooling loops are coupled to the heat exchanger.

17. A method for cooling a heat-generating structure, the method comprising:

providing a first cooling loop for circulating a first fluid coolant;

providing a second cooling loop for circulating a second fluid coolant;

cooling the heat-generating structure using the first fluid coolant;

providing a heat exchanger for cooling the first fluid coolant using the second fluid coolant, the first fluid coolant having a specific heat and a mass flow rate, the second fluid coolant having a specific heat and a mass flow rate, a product of the specific heat and the mass flow rate of the first fluid coolant being greater than a product of the specific heat and the mass flow rate of the second fluid coolant.

18. The method of claim 17, wherein the heat-generating structure is a phased array antenna.

19. The method of claim 18, further comprising providing a chiller for cooling the second fluid coolant, the chiller being located remotely from the heat-generating structure and the heat exchanger.

20. The method of claim 17, wherein a product of the specific heat and the mass flow rate of the first fluid coolant being greater than a product of the specific heat and the mass flow rate of the second fluid coolant further comprises a product of the specific heat, the mass flow rate, and an inverse of a viscosity of the first fluid coolant being greater than a product of the specific heat, mass flow rate, and an inverse of a viscosity of the second fluid coolant.

21. The method of claim 20, wherein the viscosity of the first fluid coolant is lower than the viscosity of the second fluid coolant.

22. The method of claim 17, wherein the specific heat of the first fluid coolant is higher than the specific heat of the second fluid coolant.

23. The method of claim 17, wherein the mass flow rate of the first fluid coolant is higher than the mass flow rate of the second fluid coolant.

24. The method of claim 17, wherein the first fluid coolant includes a fluid coolant selected from a group consisting of a mixture of water and propylene glycol (PGW), a mixture of water and ethylene glycol (EGW), and HFC-134a.

25. The method of claim 17, wherein the second fluid coolant includes a fluid coolant selected from a group consisting of polyalphaolefin (PAO) and Coolanol.

26. The method of claim 23, wherein the second fluid coolant includes a fluid coolant selected from a group consisting of a mixture of water and propylene glycol (PGW) and a mixture of water and ethylene glycol (EGW).