COOLING SYSTEM

Abstract

A cooling system for a heat source includes a heat source loop, a refrigerant loop, and a controller. The heat source loop provides a closed fluid path for a process fluid and fluidly connects a valve, a bypass leg and/or a heat exchange leg having a heat exchanger, and a pump. The process fluid is disposed within a portion of the loop and is subject to heat transfer from the heat source. The valve is disposed downstream of the heat source portion of the loop, wherein the valve is selectively operable to direct process fluid to the bypass leg and/or the heat exchanger leg. The refrigerant loop provides a closed fluid path for a fluid refrigerant and fluidly connects the heat exchanger, a refrigerant compressor, a refrigerant condenser, and a refrigerant regulator. The controller is in communication with the valve and is adapted to control the valve to regulate an amount of process fluid entering the bypass leg and the heat exchanger leg.

Description

Applicant hereby claims priority benefits under 35 U.S.C. §119(e) of U.S. Provisional Patent Application No. 61/230,156 filed Jul. 31, 2009, the disclosure of which is herein incorporated by reference.

BACKGROUND OF THE INVENTION

1. Technical Field

This disclosure relates generally to a cooling system and, in particular, to a cooling system for regulating the temperature of a heat source.

2. Background Information

Heat exchange systems are widely used to regulate environmental temperatures and conditions. For example, temperature in certain portions of a hybrid power system (e.g., the batteries in a hybrid vehicle) are regulated to improve system performance and to reduce/prevent degradation and damage caused by overheating.

Typically, there are two methods for regulating the temperature (e.g. cooling) of batteries in a hybrid vehicle. In a first method, heat is transferred from the batteries to a process fluid disposed within a heat transfer jacket and thereafter from the process fluid into ambient air via a radiator. This method may be limited by the size of the radiator and the temperature of the ambient air in contact with the radiator. In a second method, an air conditioning system that includes refrigerant, a condenser, and an evaporator, chills air passing within a supply duct. When the chilled air passes around the battery, heat is transferred between the battery and the airflow through radiation and convection. A disadvantage of this method is that the air may be chilled to a temperature (e.g., between 40° and 60° F.) that can overcool the batteries and reduce their performance.

SUMMARY OF THE DISCLOSURE

In one embodiment of the invention, a cooling system for a heat source includes a heat source loop, a refrigerant loop, and a controller. The heat source loop provides a closed fluid path for a process fluid and fluidly connects a valve, a bypass leg and/or a heat exchange leg having a heat exchanger, and a pump. The process fluid is disposed within a portion of the loop and is subject to heat transfer from the heat source. The valve is disposed downstream of the heat source portion of the loop, wherein the valve is selectively operable to direct process fluid to the bypass leg and/or the heat exchanger leg. The refrigerant loop provides a closed fluid path for a fluid refrigerant and fluidly connects the heat exchanger, a refrigerant compressor, a refrigerant condenser, and a refrigerant regulator. The controller is in communication with the valve and is adapted to control the valve to regulate an amount of process fluid entering the bypass leg and the heat exchanger leg.

In another embodiment of the invention, a method for regulating temperature of a heat source includes the steps of: (1) providing a cooling system having a heat source loop, a refrigerant loop and a controller, which heat source loop includes a heat transfer portion thermally coupled to the heat source, a bypass leg, and a heat exchanger, which refrigerant loop includes the heat exchanger, a refrigerant compressor, a refrigerant condenser, and a refrigerant regulator; (2) circulating process fluid through the heat source loop; (3) selectively directing the process fluid from the heat transfer portion of the heat source loop to at least one of the bypass leg and the heat exchanger to regulate the temperature of the heat source within a predetermined temperature range; and (4) circulating fluid refrigerant through the refrigerant loop when at least a portion of the process fluid is directed to the heat exchanger.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a diagrammatic illustration of one embodiment of a cooling system.

FIG. 2 is a diagrammatic illustration of another embodiment of the cooling system in FIG. 1.

DETAILED DESCRIPTION OF THE INVENTION

FIG. 1 is a diagrammatic illustration of one embodiment of a cooling system 10 for regulating the temperature of at least one heat source such as, but not limited to, at least one battery 12 in, for example, a hybrid vehicle. Other heat sources may include, but are not limited to motors and/or one or more electrical components (e.g., an alternator, an inverter, a direct current (“dc”) to alternating current (“ac”) converter, etc.). The cooling system 10 includes a heat source loop 14, a refrigerant loop 16 and a controller 18.

The heat source loop 14 in this embodiment is a closed fluid path for a process fluid such as, but not limited to, water, brine, and/or antifreeze. The heat source loop 14 includes a heat transfer portion 20, a valve 22, a bypass leg 24, an evaporator leg 26, and a pump 28. In some embodiments, the heat source loop 14 further includes an ambient heat exchange leg 30 (illustrated in FIG. 2).

The heat transfer portion 20 of the heat source loop 14 includes a heat transfer device 32 disposed between an inlet 21 and an outlet 23. The heat transfer device 32 is operable to permit the transfer of thermal energy from the heat source 12 (e.g., battery) to a process fluid. An example of an acceptable heat transfer device 32 is a jacket enclosure that includes a fluid passage disposed between walls 27. One of the walls 27 is positioned in close proximity to an exterior surface of the battery 12.

The valve 22 has a plurality of outlets and is operable to selectively direct at least a portion of the process fluid to one or more of the outlets. For example, in the embodiment illustrated in FIG. 1, the valve 22 is a three-way valve having an inlet 29, a first outlet 31, and a second outlet 33. Process fluid received through the inlet 29 of the three-way valve is selectively directed to one or both of the first outlet 31 and second outlet 33 of the valve. The valve 22 is not limited to the aforesaid three-way configuration, however. Other configurations may include a plurality of independent valves (e.g., a first valve 34 and a second valve 36 as is illustrated in FIG. 2), that may be synchronously configured to selectively direct process fluid to one or more of their outlets.

The bypass leg 24 extends between an inlet 35 and an outlet 37.

The evaporator leg 26 of the heat source loop 14 includes a section that passes between an inlet 39 and an outlet 41 of a first side 38 of an evaporator 40. The evaporator 40 has a second side 42 through which refrigerant passes as part of the refrigerant loop 16, as will be described below. The evaporator 40 is operable to transfer thermal energy from the process fluid, to the evaporator 40, and subsequently to the refrigerant.

Referring now to FIG. 2, in those embodiments of the heat source loop 14 that include an ambient heat exchange leg 30, the ambient heat exchange leg 30 includes an ambient air heat exchanger (e.g., a radiator 44) disposed between an inlet 43 and an outlet 45. The radiator 44 is operable to thermally couple the process fluid flowing within the radiator 44 with ambient air flowing through and/or around the radiator 44. For example, where the process fluid is at a higher temperature than the ambient air, thermal energy will be transferred out of the process fluid, through walls of the radiator 44, and into the ambient air. In some embodiments, a fan 25 (e.g., a variable speed fan) is used to facilitate the flow of the ambient air through and/or around the radiator 44.

The refrigerant loop 16 is a closed fluid path for a fluid refrigerant (“refrigerant”) such as, but not limited to, R134a, etc. The refrigerant loop 16 includes an evaporator 40, a compressor 46, a condenser 48, and a refrigerant regulator 50 in line with one another to form the closed loop.

The refrigerant loop 16 includes a section that passes through the second side 42 of the evaporator 40, which section includes a second side inlet 47 and a second side outlet 49. As stated above, the evaporator 40 is operable to transfer thermal energy from the process fluid, to the evaporator 40, and subsequently to the refrigerant.

The compressor 46 has an inlet 51 and an outlet 53 and is operable to compress the refrigerant from an inlet pressure to a higher exit pressure. An example of an acceptable compressor 46 is a variable speed compressor.

The refrigerant loop 16 includes a section that passes through the condenser 48 via a condenser inlet 55 and a condenser outlet 57. The condenser 48 is operable to process the refrigerant in a manner that causes heat to transfer out of the refrigerant, through the condenser 48, and into ambient air. In some embodiments, a condenser fan 75 (e.g., a variable speed condenser fan) is used to facilitate the flow of ambient air through and/or around the condenser 48.

The refrigerant regulator 50 has an inlet 59 and an outlet 61 and is operable to meter refrigerant flowing therethrough. In some embodiments, a thermal expansion valve (“TXV”) may be used as a refrigerant regulator 50.

The controller 18 monitors and dynamically controls the cooling system 10 in order to regulate one or both of the temperature of the heat source (e.g., the battery 12) and the operational performance of one or more components of the cooling system 10. For example, the controller 18 is adapted to receive one or more feedback signals, and utilizing those feedback signals, the controller 18 is adapted to provide one or more control signals indicative of different modes of operation to one or more components of the cooling system 10. The feedback signals may include, but are not limited to, a signal indicative of the temperature of the heat source (e.g., the battery 12) and/or a signal indicative of the operational performance of components (e.g., the compressor 46) within the refrigerant loop 16. The present cooling system 10 may be operated in a variety of different modes of operation; e.g., the cooling system 10 may be operated based on the temperature of the process fluid disposed within the heat source loop 14, or based on the performance of the refrigerant loop 16, or some combination thereof. Referring to the embodiment in FIG. 2, the controller 18 includes a processor 52 in signal communication with an inverter 54 operable to selectively and incrementally provide power to and thereby control components including one or more of the valve(s), pump 28, compressor 46, and the condenser fan 75.

Referring to the embodiment shown in FIG. 1, the outlet 23 of the heat transfer portion 20 is connected (e.g. through a fluid coupling) in the heat source loop 14 to the inlet 29 of the three-way valve 22. The first outlet 31 of the three-way valve 22 is connected to the inlet 35 of the bypass leg 24, and the second outlet 33 is connected to the inlet 39 of the first side 38 of the evaporator 40. The outlet 37 of the bypass leg 24 and the outlet 41 of the evaporator 40 are connected to the inlet 21 of the heat transfer portion 20 through the pump 28.

In the embodiment of the heat source loop 14 shown in FIG. 2, the outlet 23 of the heat transfer portion 20 is connected to the inlet 63 of the first valve 34. The first outlet 65 of the first valve 34 is connected to the inlet 35 of the bypass leg 24, and the second outlet 67 of the first valve 34 is connected to the inlet 69 of the second valve 36. The first outlet 71 of the second valve 36 is connected to the inlet 39 of the first side 38 of the evaporator 40, and the second outlet 73 is connected to the inlet 43 of the ambient heat exchange leg 30. The outlets 37, 41, 45 of the bypass leg 24, the evaporator 40, and the ambient heat exchange leg 30 are connected to the inlet 21 of the heat transfer portion 20 through the pump 28.

Referring now to both FIGS. 1 and 2, in the refrigerant loop 16, the outlet 49 of the second side 42 of the evaporator 40 is connected to the inlet 51 of the compressor 46. The outlet 53 of the compressor 46 is connected to the inlet 55 of the condenser 48. The outlet 57 of the condenser 48 is connected to the inlet 59 of the refrigerant regulator 50. The outlet 61 of the refrigerant regulator 50 is connected to the inlet 47 of the evaporator 40.

The heat source loop 14 and the refrigerant loop 16 are thermally connected to one another through the first and the second sections of the evaporator 40. Examples of acceptable evaporators include counter-flow evaporators and braised plate heat exchanger evaporators (“braised plate evaporator”) having first and second fluid paths. Counter-flow and braised plate evaporators are known in the art, and therefore will not be discussed in further detail. The present invention is not limited to any particular type of evaporator, however.

The controller 18 is in communication with the components of the cooling system 10 such that it may operatively control the configuration of one or more of the valve 22 (or valves in the embodiment in FIG. 2) and the speed/output of the pump 28, the compressor 46, and/or the fan(s) 75, 25 coupled with the condenser 48 and radiator 44. For example, in the embodiment in FIG. 2, the inverter 54 is electrically coupled to the pump 28 and the compressor 46 such that the processor 52 may control the pump 28 and/or the compressor 46 by regulating the power to the inverter 54, which in turn controls the pump 28 and/or compressor 46.

During operation of the cooling system 10 embodiment shown in FIG. 2, the pump 28 responds to a pump control signal from the controller 18, and circulates the process fluid within the heat source loop 14. Heat transfers from the battery 12, through the heat transfer jacket 32, and into the process fluid. The now heated process fluid flows from the heat transfer portion 20 and into the first valve 34.

In a first mode of operation, the first valve 34 responds to a valve control signal from the controller 18, and directs at least a portion of the heated process fluid towards the second valve 36. The second valve 36 responses to another valve control signal from the controller 18, and directs at least a portion of the heated process fluid into the first side 38 of the evaporator 40. Heat from the heated process fluid is transferred through the first and the second sides 38, 42 of the evaporator 40 into the refrigerant disposed within the refrigerant loop 16. The now cooled process fluid flows from the evaporator leg 26 back towards the pump 28, where it is recirculated.

In the refrigerant loop 16, the now heated refrigerant flows from the evaporator 40 and into the compressor 46, where the heated refrigerant is compressed. The now heated and compressed refrigerant flows from the compressor 46 and into the condenser 48. Heat from the refrigerant is transferred, through the condenser 48, into ambient air directed through and/or around the condenser 48 via the condenser fan 75. The now cooled and lower pressure refrigerant flows from the condenser 48 and into the refrigerant regulator 50, where the regulator meters the quantity of the refrigerant that flows back into the evaporator 40, where the cycle begins again. In some embodiments, one or more of the compressor 46 and the condenser fan 75 are responsive to a control signal(s) from the controller 18 to increase or decrease their speed/output, which thereby increases or decreases the rate at which heat is transferred from the refrigerant to the ambient air.

In a second mode of operation, in the heat source loop 14, the first valve 34 responds to another valve control signal from the controller 18, and directs at least a portion of the heated process fluid towards the second valve 36. The second valve 36 responds to another valve control signal from the controller 18, and directs at least a portion of the heated process fluid into the radiator 44 disposed within the ambient heat exchange leg 30. As the process fluid passes through the radiator 44, heat transfers from the process fluid, through the radiator 44, into the ambient air directed through and/or around the radiator 44 via the radiator fan 25. The now cooled process fluid exits the radiator 44 and flows toward the pump 28, where it is recirculated. In some embodiments, the radiator fan 25 responds to a control signal from the controller 18 to increase or decrease its speed/output, which thereby increases or decreases the rate at which heat is transferred from the process fluid to the ambient air.

In a third mode of operation, in the heat source loop 14, the first valve 34 responds to another valve control signal from the controller 18, and directs at least a portion of the process fluid into the bypass leg 24. The process fluid flows through the bypass leg 24 and back towards the pump 28, where it is recirculated.

The controller 18 regulates the temperature of the battery 12 within a predetermined range, for example, by utilizing at least one of the aforesaid three modes of operation. For example, where the battery 12 has a high temperature (relative to ambient), the controller 18 may signal the first valve 34 and the second valve 36 in the heat source loop 14 to direct the majority (e.g. greater than fifty percent) of the heated process fluid through the evaporator 40 where it is cooled by the refrigerant passing through the opposite side of the evaporator 40. The remaining heated process fluid passes through the ambient heat exchange leg 30. In another example, where the battery 12 has a slightly elevated temperature, the controller 18 may signal the first valve 34 and the second valve 36 in the heat source loop 14 to direct the majority (e.g. greater than fifty percent) of the heated process fluid through the bypass leg 24, and the remaining portion of the heated process fluid through the ambient heat exchange leg 30. The predetermined temperature range, and the cooling path configuration selected to best achieve that temperature, is selected to optimize (i.e., increase) the performance and/or the efficiency of the heat source. For example, the predetermined temperature range is set between sixty and one hundred degrees Fahrenheit (60°-100° F.) for battery types used in hybrid vehicles. The present cooling system contemplates that the controller 18 can control the process flow to flow in a variety of different paths in a variety of different relative portions to arrive at a desirable cooling configuration, and the present invention is not limited to the examples described above.

The controller 18 may further regulate the operational performance of the components of the cooling system. For example, where the controller 18 receives a feedback signal which indicates that the compressor 46 is operating beyond a predetermined tolerance, the controller 18 turns the compressor 46 off by signaling the inverter 54 to cutoff power thereto. The controller 18 may additionally signal the first and the second valves 34, 36 to direct the process fluid through the bypass leg 24 and the ambient heat exchange leg 30, and not through the first side 38 of the evaporator 40. In another example, the controller 18 may signal the inverter 54 to increase or decrease power provided to the pump 28 to increase or decrease the flowrate of the process fluid flowing through the heat source loop 14 to increase the efficiency of the system.

While various embodiments of the present invention have been disclosed, it will be apparent to those of ordinary skill in the art that many more embodiments and implementations are possible within the scope of the invention. Accordingly, the present invention is not to be restricted except in light of the attached claims and their equivalents.

Claims

1. A cooling system for a heat source, comprising:

a heat source loop that provides a closed fluid path for a process fluid, which loop fluidly connects a valve, at least one of a bypass leg and a heat exchange leg having a heat exchanger, and a pump, wherein the process fluid disposed within a portion of the loop is subject to heat transfer from the heat source, and the valve is disposed downstream of the heat source portion of the loop, wherein the valve is selectively operable to direct process fluid to at least one of the bypass leg and the heat exchanger leg;

a refrigerant loop that provides a closed fluid path for a fluid refrigerant, which refrigerant loop fluidly connects the heat exchanger, a refrigerant compressor, a refrigerant condenser, and a refrigerant regulator; and

a controller in communication with the valve and adapted to control the valve to regulate an amount of process fluid entering the bypass leg and the heat exchanger leg.

2. The cooling system of claim 1, wherein the heat source is a battery.

3. The cooling system of claim 1, wherein the heat source is an electrical component.

4. The cooling system of claim 1, wherein the heat source loop further includes a second heat exchange leg having an ambient air heat exchanger.

5. The cooling system of claim 1, wherein the valve includes a plurality of valves.

6. The cooling system of claim 1, wherein the valve is a three-way valve.

7. The cooling system of claim 1, wherein the pump is a variable speed pump.

8. The cooling system of claim 1, wherein the refrigerant compressor is a variable speed compressor.

9. The cooling system of claim 8, wherein the controller is configured in communication with the variable speed compressor for regulating operational performance thereof.

10. The cooling system of claim 1, wherein the controller includes a processor in signal communication with an inverter.

11. The cooling system of claim 10, wherein the inverter is electrically coupled to the refrigerant compressor.

12. The cooling system of claim 1, wherein the refrigerant regulator is configured as a thermal expansion valve.

13. The cooling system of claim 1, further comprising a fan configured to facilitate airflow through the refrigerant condenser.

14. The cooling system of claim 13, wherein the fan is a variable speed fan.

15. The cooling system of claim 4, further comprising a fan configured to facilitate airflow through the ambient air heat exchanger.

16. The cooling system of claim 15, wherein the fan is a variable speed fan.

17. A method for regulating temperature of a heat source, comprising:

providing a cooling system having a heat source loop, a refrigerant loop and a controller, which heat source loop includes a heat transfer portion thermally coupled to the heat source, a bypass leg, and a heat exchanger, which refrigerant loop includes the heat exchanger, a refrigerant compressor, a refrigerant condenser, and a refrigerant regulator;

circulating process fluid through the heat source loop;

selectively directing the process fluid from the heat transfer portion of the heat source loop to at least one of the bypass leg and the heat exchanger to regulate the temperature of the heat source within a predetermined temperature range; and

circulating fluid refrigerant through the refrigerant loop when at least a portion of the process fluid is directed to the heat exchanger.

18. The method of claim 17, wherein the predetermined temperature range is between sixty degrees and one hundred degrees Fahrenheit.

19. The method of claim 17, wherein the process fluid is selectively directed using a valve.

20. The method of claim 19, further comprising controlling the valve using the controller.