US20100186440A1

US20100186440A1 - Thermal storage for co2 system

Info

Publication number: US20100186440A1
Application number: US12/360,540
Authority: US
Inventors: Kwangtaek Hong; Bryan Styles
Original assignee: Denso International America Inc
Current assignee: Denso International America Inc
Priority date: 2009-01-27
Filing date: 2009-01-27
Publication date: 2010-07-29

Abstract

A climate control system may include a cooling system having a compressor in fluid communication with a condenser and a evaporator and circulating a first fluid therebetween; a first heat exchanger in fluid communication with the cooling system and operable to remove heat from a second fluid; a reservoir in fluid communication with the first heat exchanger and adapted to receive the second fluid; a pump in fluid communication with the first heat exchanger and the reservoir and circulating the second fluid therebetween; a second heat exchanger in selective fluid communication with the first heat exchanger, the reservoir and the pump; and a valve movable between a first position allowing fluid communication between the reservoir and the second heat exchanger and a second position preventing fluid communication between the reservoir and the second heat exchanger, wherein heat is absorbed by the second fluid flowing through the second heat exchanger.

Description

FIELD

The present disclosure relates to a climate control system and more particularly, to a thermal storage system for a climate control system.

BACKGROUND

This section provides background information related to the present disclosure which is not necessarily prior art. Many modern vehicles, such as automobiles, include climate control systems or air conditioning systems that operate to cool a passenger compartment of a vehicle. Such climate control systems typically include a compressor to circulate a refrigerant or other working fluid through the system. The compressor is often driven by the engine of the vehicle via a belt or other power transmission means.
Gas-electric hybrid vehicles are becoming more popular as vehicle fuel efficiency becomes increasingly more important to modern consumers. Such hybrid vehicles are often propelled by an internal combustion engine and an electric motor which may operate simultaneously or independently of each other to reduce the engine's fuel consumption. Continuous operation of the climate control system is often dependent upon continuous and efficient operation of the engine-driven compressor. Accordingly, a reduction in the engine's output and/or deactivation of the engine in a hybrid vehicle may reduce the cooling capacity and/or interrupt efficient operation of the cooling system. This may adversely affect a driver or passenger's comfort and enjoyment of the vehicle.

SUMMARY

This section provides a general summary of the disclosure, and is not a comprehensive disclosure of its full scope or all of its features. In one form, the present disclosure provides a thermal storage system that may include a cooling system including a condenser, an evaporator and a compressor in fluid communication with the condenser and the evaporator. The compressor causes the circulation of a first fluid between the condenser and the evaporator, and throughout the entire system. A first heat exchanger may be in fluid communication with the cooling system and operable to remove heat from a second fluid. A reservoir may be in fluid communication with the first heat exchanger and be adapted to receive the second fluid. A pump may be in fluid communication with the first heat exchanger and the reservoir and circulate the second fluid therebetween. A second heat exchanger may be in selective fluid communication with the first heat exchanger, the reservoir and the pump. A valve may be movable between a first position, allowing fluid communication between the reservoir and the second heat exchanger, and a second position, preventing fluid communication between the reservoir and the second heat exchanger. Heat may be absorbed by the second fluid flowing through the second heat exchanger.
In another form, the present disclosure may provide a climate control system that may include a first fluid circuit. The first fluid circuit may include an evaporator, an accumulator and a compressor. The compressor may cause the circulation of the first fluid through the first fluid circuit. A second fluid circuit may include a coil, a reservoir, and a pump. The pump may cause the circulation of a second fluid through the second fluid circuit. A heat exchanger may be in selective fluid communication with the second fluid circuit. A coil may be disposed in an accumulator and the first fluid in the accumulator may absorb heat from the second fluid flowing through the coil. A valve may be movable between a first position allowing the second fluid to flow through the heat exchanger and a second position causing the second fluid to bypass the heat exchanger. A fan may be positioned to force air across or through the evaporator and the heat exchanger.
In yet another form, the present disclosure may provide a climate control system that may include a first fluid circuit that employs an evaporator, a first tube and a compressor, which circulates a first fluid through the first fluid circuit. The system may further employ a second fluid circuit including a second tube, a reservoir, and a pump to circulate a second fluid through the second fluid circuit. A second heat exchanger may be in selective fluid communication with the second fluid circuit. A valve may be movable between a first position allowing the second fluid to flow through the second heat exchanger and a second position causing the second fluid to bypass the second heat exchanger. A fan may be adapted to force air across or through the evaporator and the second heat exchanger. The first tube and the second tube may be substantially coaxial and the first fluid flowing through the first tube may absorb heat from the second fluid flowing through the second tube.
Further areas of applicability will become apparent from the description provided herein. The description and specific examples in this summary are intended for purposes of illustration only and are not intended to limit the scope of the present disclosure.

DRAWINGS

The drawings described herein are for illustrative purposes only of selected embodiments and not all possible implementations, and are not intended to limit the scope of the present disclosure.

FIG. 1 is a schematic representation of a vehicle having a climate control system according to the principles of the present disclosure;

FIG. 2 is a schematic representation of an embodiment of the climate control system in a charging mode according to the principles of the present disclosure;

FIG. 3 is a schematic representation of the climate control system of FIG. 2 in a discharging mode according to the principles of the present disclosure;

FIG. 4 is a partial perspective view of the climate control system having an internal heat exchanger according to the principles of the present disclosure;

FIG. 5 is a schematic cross-sectional view of the internal heat exchanger according to the principles of the present disclosure;

FIG. 6 is a partial perspective view of the internal heat exchanger having a portion of an outer tube cut away;

FIG. 7 is a schematic representation of another embodiment of the climate control system in a charging mode according to the principles of the present disclosure; and

FIG. 8 is a schematic representation of the climate control system of FIG. 7 in a discharging mode according to the principles of the present disclosure.

Corresponding reference numerals indicate corresponding parts throughout the several views of the drawings.

DETAILED DESCRIPTION

Example embodiments will now be described more fully with reference to the FIGS. 1-8. A climate control system 10 is provided and may include a primary cooling system 12 and an auxiliary cooling system or thermal storage system 14, both of which may be installed in a vehicle 16 and may cooperate to control a temperature within a passenger compartment of the vehicle 16. The vehicle 16 could be a hybrid vehicle selectively powered by an internal combustion engine 18 and an electric power source 20, or both. The internal combustion engine 18 may power the primary cooling system 12 and the electric power source 20 may power the thermal storage system 14.
The primary cooling system 12 may include a first fluid circuit having a compressor 22, a gas cooler or condenser 24, an internal heat exchanger 26, an expansion device 28, an evaporator 30, and an accumulator 32. The compressor 22 may circulate or pump a first fluid, such as carbon dioxide or R-134a, for example, through the primary cooling system 12. It will be appreciated that the first fluid could be any other refrigerant or coolant suitable to cool an automobile cabin.
The compressor 22 may be operable to draw relatively low pressure fluid, compress the fluid to a relatively higher pressure and discharge the fluid at the relatively high pressure. The compressor 22 can be a reciprocating compressor, a scroll compressor, or a rotary vane compressor, for example, or any other suitable type. The compressor 22 may be driven by the internal combustion engine 18 via a belt or any other suitable means of transmitting rotary power. The condenser 24 may include a heat exchanger or coil having an inlet 34 adapted to receive the high pressure fluid from the compressor 22. The fluid may reject heat to the ambient air as it flows through the coil. The fluid may then exit the condenser 24 through an outlet 36. It will be appreciated that the condenser 24 could be a gas cooler, a radiator, or any other suitable heat exchanger. The expansion device 28 may be an expansion valve or an orifice tube, for example, adapted to allow the first fluid to expand, thereby lowering the pressure and temperature of the fluid as it flows therethrough. The expansion device 28 may be fluidly coupled with the internal heat exchanger 26 and the evaporator 30.
The evaporator 30 may include a heat exchanger or coil having an inlet 38 adapted to receive the first fluid from the expansion device 28. The fluid may absorb heat from the ambient air as it flows through the coil. The fluid may then exit the evaporator 30 through an outlet 40. A fan 42 may force the ambient air across the coil of the evaporator 30 to facilitate heat transfer therebetween. Air forced across the evaporator 30 may be subsequently channeled through one or more ducts to the passenger compartment of the vehicle 16, for example.
With more particular reference to FIG. 4-6, the internal heat exchanger 26 may be disposed downstream of the condenser 24 and may include a plurality of generally coaxial tubes or pipes including an inner pipe 44, an intermediate pipe 46, and an outer pipe 48. The inner pipe 44 may include a first end 50 and a second end 52. The first end 50 may be fluidly coupled to the outlet 36 of the condenser 24. The second end 52 may be fluidly coupled to the expansion device 28. In this manner, high pressure fluid may flow from the condenser 24, through the inner pipe 44 to the expansion device 28. The inner pipe 44 can have a generally circular cross-section and may be formed from aluminum, steel, or any other suitable material or combination of materials.
The intermediate pipe 46 may include a first end 54 and a second end 56. The first end 54 may be sealed around the inner pipe 44 and may include an inlet 58. The inlet 58 may be fluidly coupled to the outlet 40 of the evaporator 30. The second end 56 may also be sealed around the inner pipe 44 and may include an outlet 60. The outlet 60 may be fluidly coupled to the accumulator 32. In this manner, the low pressure fluid exiting the evaporator 30 may flow through the intermediate pipe 46 to the accumulator 32. The intermediate pipe 46 can have a generally circular cross-section and at least a portion thereof may be spiraled, as depicted in FIG. 6, which may define a spiral or helical flow path through the intermediate pipe 46 between the outer diameter of the inner pipe 44 and the inner diameter of the intermediate pipe 46. The spiral portion may also define a spiral flow path through the outer pipe 48 between the outer diameter of the intermediate pipe 46 and the inner diameter of the outer pipe 48. The spiral flow path may increase heat transfer between the high pressure fluid flowing through the inner pipe 44 and the low pressure fluid flowing through the intermediate pipe 46. The intermediate pipe 46 may be formed from aluminum, steel, or any other suitable material or combination of materials.
The outer pipe 48 may include a first end 62 and a second end 64. The first end 62 may be sealed around the intermediate pipe 46 and may include an inlet 66. The second end 64 may also be sealed around the intermediate pipe 46 and may include an outlet 68. In this manner, a second fluid may flow into the inlet 66, through the outer pipe 48 and exit through the outlet 68. The outer pipe 48 can have a generally circular cross-section and may be formed from aluminum, steel, or any other suitable material or combination of materials.
It will be appreciated that the internal heat exchanger 26 could be otherwise formed. The plurality of pipes 44, 46, 48 could have any suitable geometry, and could include one or more non-coaxial pipes. The accumulator 32 may receive a mixture of liquid and vapor fluid from the intermediate pipe 46 of the internal heat exchanger 26. The accumulator 32 may separate liquid and vapor portions of the fluid, store the liquid in a reservoir and allow the vapor to be drawn into the compressor 22.
The thermal storage system 14 may be a second fluid circuit and may include a pump 70, the outer pipe 48 of the internal heat exchanger 26, a reservoir 72, a first valve 74, a second valve 75, a heat exchanger 76, and a bypass line 77. The pump 70 may circulate a second fluid, such as engine coolant (e.g., an ethylene glycol based coolant, a propylene glycol based coolant, or any other suitable coolant), through the thermal storage system 14. As will be subsequently described, the thermal storage system 14 may charge or remove heat from the second fluid while the compressor 22 is operating and may supplement the cooling capacity of the primary cooling system 12 when the compressor 22 is deactivated or the cooling capacity of the primary cooling system 12 is otherwise inadequate.
The pump 70 may be an electric pump and may be powered by the electric power source 20 (FIG. 1) or any other battery. The pump 70 may be a positive displacement pump, for example, or any other suitable pump adapted to circulate the second fluid through the thermal storage system 14. The pump 70 may include an inlet 78, through which the second fluid may be drawn, and an outlet 80, through which the second fluid may be discharged. The outlet 80 may be fluidly coupled to the inlet 66 of the outer pipe 48 of the internal heat exchanger 26. In this manner, the second fluid may flow from the outlet 80 of the pump 70 into the inlet 66, through the outer pipe 48 and exit through the outlet 68 of the outer pipe 48. As the second fluid flows through the outer pipe 48, heat from the second fluid may be absorbed by the first fluid flowing through the intermediate pipe 46.
The reservoir 72 may be a bottle, tank or other container adapted to store the second fluid. The reservoir 72 may include an inlet 82 and an outlet 84. The inlet 82 may be fluidly coupled to the outlet 68 of the outer pipe 48. The reservoir 72 may store additional fluid beyond the amount than can be circulating through the thermal storage system 14 at any given moment. Fluid entering through the inlet 82 may mix with the fluid stored in the reservoir 72, and a portion of the fluid therein may exit through the outlet 84. The reservoir 72 may be formed from a polymeric material, for example, or any other insulating material. The size and shape of the reservoir 72 may be dictated by various factors including vehicle packaging constraints, the desired cooling capacity of the thermal storage system 14, the thermal properties of the second fluid, and/or other performance, space and cost requirements.
The outlet 84 of the reservoir 72 may be fluidly coupled to the first valve 74. The first valve 74 may be a three-way valve including an inlet 86, a first outlet 88 and a second outlet 90. The first valve 74 may be selectively moveable between a first position and a second position. In the first position, the second fluid may be allowed to flow from the reservoir 72 into the inlet 86 and through the second outlet 90 to the heat exchanger 76. In the second position, the second fluid may be prevented from flowing through the second outlet 90 and reaching the heat exchanger 76 and instead may exit through the first outlet 88 and flow through the bypass line 77. The first valve 74 could be a solenoid valve, for example, or any other suitable type of valve. A controller 92 may be in electrical communication with the first valve 74 and may cause the first valve 74 to move between the first and second positions, as will be subsequently described.
The heat exchanger 76 may include a coil through which the second fluid may flow when the first valve 74 is in the first position. The heat exchanger 76 may be disposed proximate the evaporator 30 and generally aligned therewith, such that the fan 42 may force air across the coil of the evaporator 30 and the coil of the heat exchanger 76. In this manner, heat from the air may be absorbed by the second fluid, thereby cooling the air as it is forced across the coil of the heat exchanger 76.
The second valve 75 may be a three-way valve fluidly coupled to the bypass line 77, the heat exchanger 76 and the pump 70. The second valve 75 may be adapted to prevent fluid received from the bypass line 77 from flowing to the heat exchanger 76 and may be adapted to prevent fluid received from the heat exchanger 76 from flowing to the bypass line 77. The second valve 75 could be a check valve or solenoid valve in communication with the controller 92, for example, or any other suitable type of valve.
With continued reference to FIGS. 1-6, operation of the climate control system 10 will be described in detail. As described above, the primary cooling system 12 may be a first fluid circuit operable to cool the passenger compartment of the vehicle 16. When the cooling capacity of the primary cooling system 12 is insufficient to adequately cool the passenger compartment of the vehicle 16, the thermal storage system 14 (the second fluid circuit) may provide cooling capacity to cool the passenger compartment, as will be subsequently described.
The thermal storage system 14 may be operable in a charging mode (FIG. 2) and a discharging mode (FIG. 3). While the primary cooling system 12 is operating, the thermal storage system 14 may operate in the charging mode to cool the second fluid in the thermal storage system 14. Since the compressor 22 is driven by the engine 18, the primary cooling system 12 may operate only while the engine 18 is operating. When the engine 18 is shutoff or deactivated, the controller 92 may cause the thermal storage system 14 to operate in the discharge mode, whereby the thermal storage system 14 may cool the passenger compartment.
In the charging mode (FIG. 2), the first valve 74 may be in the second position, such that fluid may flow from the reservoir 72 to the bypass line 77 and may be prevented from flowing to the heat exchanger 76. In this manner, the pump 70 circulates the second fluid through the outer pipe 48 of the internal heat exchanger 26, through the reservoir, through the bypass line 77 and back to the pump 70, where the cycle may be repeated. As described above, the first fluid absorbs heat from the second fluid in the internal heat exchanger 26. Therefore, as the thermal storage system 14 continues to operate in the charging mode, the second fluid flowing therethrough and stored in the reservoir 72 may continue to lose more and more heat (i.e., the second fluid becomes increasingly colder). Since the reservoir 72 stores more fluid than the system can circulate at any given moment, the reservoir 72 can build-up additional cooled (or charged) coolant, thereby increasing the cooling capacity of the thermal storage system 14.
The controller 92 may switch the thermal storage system 14 into the discharge mode by moving the first valve 74 into the first position, thereby allowing the second fluid to flow through the heat exchanger 76 (FIG. 3). In this configuration, the second fluid may flow from the pump 70, through the outer pipe 48 of the internal heat exchanger 26, through the reservoir 72, and through the coil of the heat exchanger 76, where the second fluid may absorb heat from the air forced over the coil by the fan 42 and thereby provide cooled air to the cabin of a vehicle. From the heat exchanger 76, the fluid may flow back to the pump 70, where the cycle may be repeated.
The controller 92 may move the first valve 74 from the second position (the charging mode) to the first position (the discharging mode) in response to one or more of a plurality of predetermined conditions. Such predetermined conditions may include insufficient cooling capacity of the primary cooling system 12, shutdown or deactivation of the compressor 22, and/or shutdown or deactivation of the engine 18. It will be appreciated that in an embodiment where the vehicle 16 is a hybrid vehicle, the engine 18 may be periodically deactivated in favor of the electric power source 20 to reduce the fuel consumption of the vehicle 16. Since the compressor 22 may be driven by the engine 18, deactivating the engine 18 may shutdown the primary cooling system 12. In such an instance, the controller 92 may switch the thermal storage system 14 into the discharging mode to maintain capacity of the climate control system 10 to cool the passenger compartment of the vehicle 16.
If the primary cooling system 12 shuts down or is deactivated because a user (e.g., a passenger or driver) has turned off the air conditioning in the vehicle 16 (i.e., the air conditioning is no longer demanded), the first valve 74 may remain in the second position (the charging mode), and/or the pump 70 may be shut down to discontinue operation of the thermal storage system 14.
Referring now to FIGS. 7, and 8, another embodiment of the climate control system will be described and will be hereinafter referred to as the climate control system 110. The climate control system 110 may include a primary cooling system 112, a thermal storage system 114, and the fan 42 described above. Similar to the climate control system 10 described above, the primary cooling system 112 may be a first fluid circuit operable to cool the passenger compartment of the vehicle 16. When the cooling capacity of the primary cooling system 112 is insufficient to adequately cool the passenger compartment of the vehicle 16, the thermal storage system 114 (a second fluid circuit) may provide cooling capacity, such as additional cooling capacity, to cool the passenger compartment to the temperature desired.
The primary cooling system 112 may include the compressor 22, the condenser (or gas cooler) 24, the expansion device 28, and the evaporator 30, all of which may have substantially similar structure and function as described above with reference to the primary cooling system 12. The primary cooling system 112 may also include an internal heat exchanger 126 and an accumulator 132. The primary cooling system 11 2 may circulate the first fluid in a similar manner as described above.
The internal heat exchanger 126 may include a first pipe 144 and a second pipe 146, which may be coaxial and include similar structures as any of the inner, intermediate and/or outer pipes 44, 46, 48 previously described above. For example, either or both of the first and second pipes 144, 146 may include a circular or spiral cross-section, as shown in FIGS. 5 and 6. The first pipe 144 may be fluidly coupled to the condenser 24 and the expansion device 28. The second pipe 146 may be fluidly coupled to the evaporator 30 and the accumulator 132. Fluid flowing through the second pipe 146 may absorb heat from the fluid flowing through the first pipe 144.
The thermal storage system 114 may include the pump 70, the reservoir 72, the first and second valves 74, 75, the heat exchanger 76, the bypass line 77, and controller 92, all of which may have substantially similar structure and function as described above with reference to the thermal storage system 14. The thermal storage system 114 may also include a coil 148 fluidly coupled with the pump 70 and the reservoir 72. The coil 148 may be disposed in the accumulator 132, such that liquid fluid being stored in the accumulator 132 may at least partially surround the coil 148. In this manner, the first fluid in the accumulator 132 may absorb heat from the second fluid flowing through the coil 148, thus lowering the temperature of the second fluid.
Operation of the climate control system 110 may be substantially similar as the operation of the climate control system 10 described above in that the thermal storage system 114 may circulate the second fluid in the charging mode and discharging mode. However, in the thermal storage system 114, the second fluid may be charged (i.e., cooled) as it flows through the coil 148 disposed in the accumulator 132. In this manner, the coil 148 and the accumulator 132 function as a heat exchanger operable to remove heat from the second fluid.
While the thermal storage systems 14,114 are described above as charging the second fluid via the internal heat exchanger 26 and the accumulator 132, respectively, it will be appreciated that any other heat exchanger could be configured to remove heat from the second fluid to charge the thermal storage system 14, 114. It should also be appreciated that the climate control system 10 could be used with any vehicle and is not limited to hybrid vehicles, such as hybrid automobiles and hybrid trucks. Further, the climate control systems 10, 110 could be used to cool any space, and are not limited to cooling the passenger compartments of vehicles. The climate control systems 10, 110 could be used for non-vehicle applications such as buildings.
Stated in a slightly different manner, with reference to FIGS. 2 and 6, part of what has been disclosed above is a thermal storage system employing a cooling system including a condenser 24, an evaporator 30 and a compressor 22. The compressor 22 forces a first fluid through the condenser 24 and the evaporator 30. Located in the cooling system loop, a first heat exchanger 26 utilizes the first fluid in fluid communication with the cooling system to cool, or remove heat, from a second fluid (liquid). Additionally, a reservoir 72 for storing the second fluid may be in fluid communication with the first heat exchanger via the second fluid. A pump 70 circulates the second fluid, a liquid, through the first heat exchanger 26 and the reservoir 72. As depicted in FIG. 2, the first fluid is in a first closed system that fully contains the first fluid, which changes states between a liquid and a gas, while the second fluid, which is a liquid, is also in its own contained system. Heat may be transferred between the first fluid and the second fluid.
Continuing, a second heat exchanger 76 that is filled with the second fluid, receives the second fluid from the reservoir. More specifically, the second fluid circulates from the pump 70, through the internal heat exchanger 26, into and through the reservoir 72, to the first valve 74, and then either to the second heat exchanger 76, or to the pump 70 again, and therefore bypassing the second heat exchanger 76. The first valve 74 is movable between a first position, which allows the second fluid to flow into the second heat exchanger 76 from the reservoir 72, and a second position, which allows the second fluid to bypass the second heat exchanger 76 and flow into the pump 70 to prevent fluid communication between the reservoir 72 and the second heat exchanger 76. A fan 42 blows air through the evaporator 30 and the second heat exchanger 76. The evaporator 30 and the second heat exchanger 76 may be arranged parallel to each other with a broad, flat side of each facing each other so that the air blows through the evaporator 30 first and then second heat exchanger 76. Heat is transferred from the air to the second fluid flowing through the second heat exchanger 76.
The thermal storage system may further employ a controller 92 and upon deactivation, that is turning off or discontinued rotation, of the compressor 22, the controller 92 switches valve position to permit the second fluid to flow into the second heat exchanger 76. This switching and utilization of the second heat exchanger 76 permits the vehicle cabin to have cool air blown into it by the fan 42. The internal heat exchanger 26 is adapted or designed to simultaneously receive the first fluid and the second fluid to facilitate heat transfer between the two fluids. The internal heat exchanger is adapted to simultaneously receive the first fluid from the condenser 24 in a first state (e.g. a liquid) and the first fluid from the evaporator in a second state (e.g. a gas). The thermal storage system may be installed in a hybrid vehicle. The first fluid may be carbon dioxide and the second fluid may be a liquid, such as a typical engine anti-freeze solution.
When an element or layer is referred to as being “on”, “engaged to”, “connected to” or “coupled to” another element or layer, it may be directly on, engaged, connected or coupled to the other element or layer, or intervening elements or layers may be present. In contrast, when an element is referred to as being “directly on,” “directly engaged to”, “directly connected to” or “directly coupled to” another element or layer, there may be no intervening elements or layers present. Other words used to describe the relationship between elements should be interpreted in a like fashion (e.g., “between” versus “directly between,” “adjacent” versus “directly adjacent,” etc.). As used herein, the term “and/or” includes any and all combinations of one or more of the associated listed items.
The foregoing description of the embodiments has been provided for purposes of illustration and description. It is not intended to be exhaustive or to limit the invention. Individual elements or features of a particular embodiment are generally not limited to that particular embodiment, but, where applicable, are interchangeable and can be used in a selected embodiment, even if not specifically shown or described. The same may also be varied in many ways. Such variations are not to be regarded as a departure from the invention, and all such modifications are intended to be included within the scope of the invention.

Claims

1. A thermal storage system comprising:

a cooling system including a condenser, an evaporator and a compressor, the compressor in fluid communication with the condenser and the evaporator and circulating a first fluid therebetween;

a first heat exchanger in fluid communication with the cooling system and operable to remove heat from a second fluid;

a reservoir in fluid communication with the first heat exchanger and adapted to receive the second fluid;

a pump in fluid communication with the first heat exchanger and the reservoir to circulate the second fluid therebetween;

a second heat exchanger in selective fluid communication with the first heat exchanger, the reservoir and the pump; and

a valve movable between a first position allowing fluid communication between the reservoir and the second heat exchanger and a second position preventing fluid communication between the reservoir and the second heat exchanger,

wherein heat is absorbed by the second fluid flowing through the second heat exchanger.

2. The thermal storage system of claim 1, wherein the second fluid flowing through the second heat exchanger supplements the cooling capacity of cooling system.

3. The thermal storage system of claim 1, further comprising a fan adapted to force air across the evaporator and the second heat exchanger.

4. The thermal storage system of claim 1, wherein the valve allows the second fluid to the second heat exchanger in response to deactivation of the compressor.

5. The thermal storage system of claim 1, wherein the first heat exchanger is an accumulator.

6. The thermal storage system of claim 1, wherein the first heat exchanger is an internal heat exchanger.

7. The thermal storage system of claim 6, wherein the internal heat exchanger is adapted to simultaneously receive the first fluid and the second fluid to facilitate heat transfer therebetween.

8. The thermal storage system of claim 7, wherein the internal heat exchanger is adapted to simultaneously receive the first fluid from the condenser in a first state and the first fluid from the evaporator in a second state.

9. The thermal storage system of claim 1, wherein:

the cooling system is installed in a hybrid vehicle,

the first fluid is carbon dioxide,

the second fluid is engine coolant, and

the valve allows the second fluid to flow to the second heat exchanger in response to deactivation of an internal combustion engine of the hybrid vehicle.

10. A climate control system comprising:

a first fluid circuit including an evaporator, an accumulator and a compressor circulating a first fluid through the first fluid circuit;

a second fluid circuit including a coil, a reservoir, a pump circulating a second fluid through the second fluid circuit, and a heat exchanger in selective fluid communication with the second fluid circuit, wherein the coil is disposed in the accumulator and the first fluid in the accumulator absorbs heat from the second fluid flowing through the coil;

a valve movable between a first position, allowing the second fluid to flow through the heat exchanger, and a second position causing the second fluid to bypass the heat exchanger; and

a fan adapted to force air across the evaporator and the heat exchanger.

11. The climate control system of claim 10, wherein the second fluid is cooled and stored while the valve is in the second position and the second fluid cools the air forced across the heat exchanger while the valve is in the first position.

12. The climate control system of claim 11, wherein:

the valve moves between the first and second positions based at least partially upon operation of the compressor and a demand for cool air, and

the first fluid is carbon dioxide.

13. A climate control system comprising:

a first fluid circuit including an evaporator, a first tube and a compressor circulating a first fluid through the first fluid circuit;

a second fluid circuit including a second tube, a reservoir, a pump circulating a second fluid through the second fluid circuit, and a second heat exchanger in selective fluid communication with the second fluid circuit;

a valve movable between a first position allowing the second fluid to flow through the second heat exchanger and a second position causing the second fluid to bypass the second heat exchanger; and

a fan adapted to force air across the evaporator and the second heat exchanger, wherein the first tube and the second tube are substantially coaxial and the first fluid flowing through the first tube absorbs heat from the second fluid flowing through the second tube.

14. The climate control system of claim 13, wherein the second fluid is cooled and stored while the valve is in the second position and the second fluid cools the air forced across the heat exchanger while the valve is in the first position.

15. The climate control system of claim 14, wherein:

the first fluid is carbon dioxide.

16. A thermal storage system comprising:

a cooling system including a condenser, an evaporator and a compressor, the compressor for forcing a first fluid through the condenser and the evaporator;

a reservoir for storing the second fluid, the reservoir in fluid communication with the first heat exchanger via the second fluid;

a pump that circulates the second fluid through the first heat exchanger and the reservoir;

a second heat exchanger that is filled with the second fluid and receives the second fluid from the reservoir;

a valve movable between a first position, which allows the second fluid to flow into the second heat exchanger from the reservoir, and a second position, which allows the second fluid to bypass the second heat exchanger and flow into the pump to prevent fluid communication between the reservoir and the second heat exchanger; and

a fan for blowing air through the evaporator and the second heat exchanger, wherein

the evaporator and the second heat exchanger are arranged parallel to each other in a serial fashion so that the air blows through the evaporator first and then second heat exchanger, and

heat is transferred from the air to the second fluid flowing through the second heat exchanger.

17. The thermal storage system of claim 16, further comprising a controller, wherein upon deactivation of the compressor, the controller switches valve position to permit the second fluid to flow into the second heat exchanger.

18. The thermal storage system of claim 17, wherein:

the first heat exchanger is an internal heat exchanger,

the internal heat exchanger is adapted to simultaneously receive the first fluid and the second fluid to facilitate heat transfer therebetween, and

the internal heat exchanger is adapted to simultaneously receive the first fluid from the condenser in a first state and the first fluid from the evaporator in a second state.

19. The thermal storage system of claim 18, wherein:

the thermal storage system is installed in a hybrid vehicle,

the first fluid is carbon dioxide, and

the second fluid is a liquid.