Mixed air / liquid cooling system with internal temperature control

Abstract

The invention relates to a mixed air / liquid cooling system with internal temperature control. The hybrid cooling system includes a refrigerant circuit having at least one first heat exchanger and a liquid cooling circuit having at least one second heat exchanger. A controller operates the valve assembly to selectively flow refrigerant to one or more of the refrigerant circuit and the liquid cooling circuit according to an operating mode of the hybrid cooling system. In an embodiment, when the liquid cooling circuit is operable, the controller is configured to implement a control method whereby one or more fans associated with the air cooling circuit are energized to cool at least a portion of the hybrid cooling system, such as when the hybrid cooling system is implemented as a self-contained unit. The internal temperature in a limited space is reduced.

Description

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS

[0002] This non-provisional application claims the benefit under 35 U.S.C. §119(e) of U.S. Provisional Application No. 63 / 568,297, filed on March 21, 2024, for a HYBRID AIR / LIQUID COOLING UNIT, and U.S. Provisional Application No. 63 / 757,025, filed on February 11, 2025, for a HYBRID AIR / LIQUID COOLING SYSTEM WITH INTERNAL TEMPERATURE CONTROL, the entire contents of which are incorporated herein by reference. Technical Field

[0003] The present disclosure relates generally to cooling systems for electronic devices and, more particularly, to a hybrid air / liquid cooling system with internal fan control for managing internal unit temperature. Background Art

[0004] Data centers and other computing environments house high-performance electronic equipment that must be thermally protected. Thermal protection is often achieved using cooling systems that include one or more cooling circuits that operate to transfer heat from one location to another. For example, in a data center, cooling circuits can be used to cool electronic equipment by transferring heat away from the equipment, from one space to another, from inside a building to outside the building, and so on.

[0005] Conventional cooling systems typically use a single cooling medium (e.g., air or liquid). Recent advances in cooling systems can include two types of cooling mediums within the same system, known as hybrid cooling systems. In such systems, the air cooling circuit typically includes a first heat exchanger configured to transfer heat from ambient air to a refrigerant, and the liquid cooling circuit typically includes a second heat exchanger configured to transfer heat from a liquid to a refrigerant. In use, the air cooling circuit and the liquid cooling circuit can operate simultaneously or in exclusive operation, such that when one cooling circuit is operational, the other cooling circuit is inoperable.

[0006] Traditional liquid cooling circuits include one or more pumps housed within a unit configured to circulate liquid to a cooling distribution unit (CDU) or directly to electronic equipment. While effective, a portion of the pump's energy (e.g., approximately 10%) is transferred to the air within the unit as heat. As the liquid circuit operates over time, heat can accumulate within the unit, posing a risk to the mechanical and electronic equipment within the unit. Consequently, it may be necessary to occasionally vent the air within the unit to reduce the unit's air temperature.

[0007] While dedicated exhaust fans are known for exhausting air from confined spaces (e.g., cabinets), they add cost and complexity to the unit, require dedicated ventilation, and restrict the placement of other equipment within the unit. Therefore, a need exists for a configuration for managing air temperature within a hybrid air / liquid cooling system without the need for dedicated exhaust fans. Summary of the Invention

[0008] According to one aspect, a cooling system is disclosed herein, comprising: a refrigerant circuit; an air cooling circuit in fluid communication with the refrigerant circuit, the air cooling circuit comprising at least one first heat exchanger and at least one fan, the at least one fan configured to flow air through the at least one first heat exchanger; a liquid cooling circuit in fluid communication with the refrigerant circuit, the liquid cooling circuit comprising at least one second heat exchanger and at least one pump; a valve assembly configured to selectively flow refrigerant to at least one of the air cooling circuit and the liquid cooling circuit; and a controller communicatively coupled to the valve assembly and the at least one fan. In an embodiment, the controller comprises one or more processors configured to: operate the cooling system in a first operating mode in which the air cooling circuit is operable and the liquid cooling circuit is inoperable; and operate the cooling system in a second operating mode in which the air cooling circuit is inoperable, the liquid cooling circuit is operable, and the at least one fan is selectively operable to cool at least a portion of the cooling system.

[0009] According to another aspect, the present invention discloses a hybrid air / liquid cooling unit, which includes: a cabinet defining an interior space; a refrigerant circuit contained in the interior space; an air cooling circuit contained in the interior space and fluidly connected to the refrigerant circuit, the air cooling circuit including at least one first heat exchanger and at least one fan, the at least one fan being configured to cause air to flow through the at least one first heat exchanger; a liquid cooling circuit contained in the interior space and fluidly connected to the refrigerant circuit, the liquid cooling circuit including at least one second heat exchanger and at least one pump; a valve assembly contained in the interior space and configured to selectively cause refrigerant to flow to at least one of the air cooling circuit and the liquid cooling circuit; and a controller communicatively coupled to the valve assembly and the at least one fan, the controller including one or more processors. In an embodiment, the controller is configured to: operate the hybrid air / liquid cooling unit in a first operating mode, in which the air cooling circuit is operable and the liquid cooling circuit is inoperable; and operate the hybrid air / liquid cooling unit in a second operating mode, in which the air cooling circuit is inoperable, the liquid cooling circuit is operable, and at least one fan is selectively operable to exhaust air from the interior space.

[0010] According to another aspect, a method for controlling a hybrid air / liquid cooling unit is disclosed herein. The method includes providing: a cabinet defining an interior space; a refrigerant circuit contained within the interior space; an air cooling circuit contained within the interior space and in fluid communication with the refrigerant circuit, the air cooling circuit comprising at least one first heat exchanger and at least one fan, the at least one fan configured to flow air through the at least one first heat exchanger; a liquid cooling circuit contained within the interior space and in fluid communication with the refrigerant circuit, the liquid cooling circuit comprising at least one second heat exchanger and at least one pump; and a valve assembly contained within the interior space and configured to selectively flow refrigerant to at least one of the air cooling circuit and the liquid cooling circuit. The method also includes providing: a controller communicatively coupled to the valve assembly and the at least one fan, the controller comprising one or more processors. In an embodiment, the method includes: operating, by a controller, the hybrid air / liquid cooling unit in a first operating mode, in which the air cooling circuit is operable and the liquid cooling circuit is inoperable; and operating, by the controller, the hybrid air / liquid cooling unit in a second operating mode, in which the air cooling circuit is inoperable, the liquid cooling circuit is operable, and at least one fan is selectively operable to exhaust air from the interior space.

[0011] This summary is provided solely as an introduction to the subject matter that is fully described in the following detailed description and accompanying drawings. It should not be construed as describing essential features, nor should it be used to determine the scope of the claims. Furthermore, it should be understood that both the foregoing summary and the following detailed description are illustrative only and are not necessarily limiting of the claimed subject matter. BRIEF DESCRIPTION OF THE DRAWINGS

[0012] The implementation of the present disclosure disclosed herein may be better understood when considering the following detailed description. Such description refers to the included drawings, which are not necessarily drawn to scale, and for the sake of clarity, some features may be exaggerated, while some features may be omitted or may be represented schematically. Like reference numerals in the drawings may represent and refer to the same or similar elements, features, or functions. In the drawings:

[0013] Figure 1 is a schematic diagram of a hybrid cooling system according to an example embodiment of the present disclosure;

[0014] Figure 2 is a schematic diagram of a hybrid cooling system further including a controller according to an example embodiment of the present disclosure;

[0015] Figure 3 is a schematic diagram of a hybrid cooling system including integration of new and conventional cooling circuits according to an example embodiment of the present disclosure;

[0016] Figure 4 is a schematic diagram of a hybrid cooling system further comprising a cooling distribution unit according to an example embodiment of the present disclosure;

[0017] Figure 5 is a schematic diagram of a hybrid cooling system shown operating in a first operating state corresponding to air cooling according to an example embodiment of the present disclosure;

[0018] Figure 6 is a schematic diagram of a hybrid cooling system shown operating in a second operating state corresponding to liquid cooling according to an example embodiment of the present disclosure;

[0019] Figure 7 is a schematic diagram of a hybrid cooling system shown operating in a third operating state corresponding to air and liquid cooling according to an example embodiment of the present disclosure;

[0020] Figure 8 is a schematic diagram of a cooling system including multiple cooling circuits according to an example embodiment of the present disclosure;

[0021] Figure 9 is a schematic diagram of a cooling system implemented as a hybrid air-liquid cooling unit according to an example embodiment of the present disclosure;

[0022] Figure 10 is a schematic diagram of a hybrid air / liquid cooling unit showing air flow through the unit according to an example embodiment of the present disclosure; and

[0023] Figure 11 is a flow chart illustrating a method for managing internal temperature in a hybrid air / liquid cooling unit according to an example embodiment of the present disclosure. DETAILED DESCRIPTION

[0024] Before explaining one or more embodiments of the present disclosure in detail, it should be understood that the embodiments are not limited to the details of the construction and arrangement of the parts or steps or methods set forth in the following description or illustrated in the accompanying drawings in their application. In the following detailed description of the embodiments, many specific details may be set forth to provide a more thorough understanding of the present disclosure. However, it will be apparent to those of ordinary skill in the art who benefit from the present disclosure that the embodiments disclosed herein may be practiced without some of these specific details. In other cases, well-known features may not be described in detail to avoid unnecessarily complicating the present disclosure.

[0025] As used herein, a letter following a reference number is intended to refer to an embodiment of features or elements that are similar, but not necessarily identical, to a previously described element or feature having the same reference number (e.g., 1, 1a, 1b). Such shorthand notation is used for convenience only and should not be construed as limiting the present disclosure in any way unless expressly stated to the contrary.

[0026] Furthermore, unless expressly stated to the contrary, "or" refers to an inclusive or, not an exclusive or. For example, condition A or B is satisfied by any of the following: A is true (or exists) and B is false (or does not exist); A is false (or does not exist) and B is true (or exists); and both A and B are true (or exist).

[0027] In addition, the use of "a" or "an" may be used to describe elements and components of the embodiments disclosed herein. This is done merely for convenience, and "a" and "an" are intended to include "one" or "at least one", and the singular also includes the plural unless otherwise apparent.

[0028] Finally, as used herein, any reference to "one embodiment" or "an embodiment" means that a particular element, feature, structure, or characteristic described in connection with the embodiment is included in at least one embodiment disclosed herein. The appearances of the phrase "in an embodiment" in different places in the specification are not necessarily all referring to the same embodiment, and an embodiment may include one or more of the features expressly described or inherently present herein, or any combination or subcombination of two or more such features, as well as any other features that may not necessarily be expressly described or inherently present in this disclosure.

[0029] Disclosed herein are hybrid air / liquid cooling systems implemented as units housing cooling circuits, and methods for managing air temperature within the units using internal fan control. In an embodiment, the hybrid air / liquid cooling unit includes a first heat exchanger (e.g., an evaporator coil) associated with the air cooling circuit and a second heat exchanger (e.g., a brazed plate heat exchanger (BPHE)) associated with the liquid cooling circuit. The hybrid air / liquid cooling unit can be operated to provide cooling that is 100% air cooling, 100% liquid cooling, or a mixture of air cooling and liquid cooling. When the liquid cooling circuit is operated to provide liquid cooling, an internal fan / blower associated with the air cooling circuit can be cycled on and off as needed to exhaust hot air from within the unit, thereby maintaining the internal air temperature and eliminating the need for dedicated cabinet exhaust fans and corresponding ventilation devices.

[0030] Figure 1is a system diagram illustrating a cooling system 100 for hybrid cooling of electronic equipment. In an embodiment, cooling system 100 includes a cooling circuit 102 configured to circulate a refrigerant. Suitable refrigerants may include, but are not limited to, R22, R410A, R407C, R744, R134a, R1234yf, R290, R600a, R718, and R454B. Cooling circuit 102 includes at least one compressor 104 configured to pressurize the refrigerant and at least one condenser 108 configured to remove heat from the refrigerant. Cooling circuit 102 also includes a first heat exchanger 112 associated with the air cooling circuit and a second heat exchanger 120 associated with the liquid cooling circuit. In an embodiment, first heat exchanger 112 may be an evaporator configured to absorb heat from the refrigerant, and second heat exchanger 120 may be a brazed plate heat exchanger (BPHE) configured to transfer heat from a secondary liquid (e.g., water or propylene glycol) to the refrigerant. Within the cooling circuit 102, the first heat exchanger 112 and the second heat exchanger 120 may utilize the same refrigerant (e.g., a portion of the refrigerant flowing through the first heat exchanger 112 may also flow through the second heat exchanger 120, and vice versa).

[0031] In an embodiment, the cooling system 100 further includes one or more valves 116 (e.g., expansion valves) configured to control the flow of refrigerant selectively through the first heat exchanger 112 and the second heat exchanger 120 to the one or more compressors 104. In an embodiment, the one or more valves 116 can control the percentage of refrigerant flowing as a liquid or as a gas / vapor to ensure that the refrigerant is in gas / vapor form before returning to the compressor 104.

[0032] Figure 2 is a system diagram illustrating a cooling system 100 that also includes a controller 200 configured to control the operating modes of the cooling system 100. For example, the controller 200 can control the operation of one or more valves 116 of the system to control the flow of refrigerant so that the system can operate in a first operating mode in which the air cooling circuit is operable and the liquid cooling circuit is inoperable, a second operating mode in which the liquid cooling circuit is operable and the air cooling circuit is operable, and a third operating mode in which at least a portion of the air cooling circuit and the liquid cooling circuit are operable. In embodiments, the controller 200 can control other aspects or components of the cooling system 100—for example, one or more compressors 104 and one or more fans / blowers operating within the cooling system 100, as discussed in detail below, as well as other system components.

[0033] In an embodiment, the controller 200 includes a memory 208 and one or more processors 204 that facilitate the controller 200 to control one or more functions of the cooling system 100. In an embodiment, the one or more processors 204 are configured to receive instructions (e.g., from the memory 208 or from an operator input via a user interface) for opening or closing one or more valves 116 and operating one or more fans / blowers, as described herein. In an embodiment, the one or more processors 204 are configured to send signals to the one or more valves 116 and the one or more fans / blowers based on the instructions, as described herein.

[0034] Figure 3 is a system diagram illustrating the integration of a liquid cooling circuit 300 with a conventional air cooling circuit 304 and the arrangement of one or more valves 116 for selectively flowing refrigerant through at least one of the liquid cooling circuit 300 and the air cooling circuit 304 .

[0035] Figure 4 1 is a system diagram illustrating cooling system 100 that also includes a cooling distribution unit (CDU) 400. In use, CDU 400 receives chilled secondary fluid from second heat exchanger 120 and circulates the chilled secondary fluid or chilled tertiary fluid (e.g., water or propylene glycol) that exchanges heat with the secondary fluid via CDU 400 to electronic equipment 404 (e.g., servers). Heat from electronic equipment 404 heats the secondary fluid or tertiary fluid, and heat from these fluids is transferred back to second heat exchanger 120 via the circulation. In embodiments, secondary fluid may also circulate directly between second heat exchanger 120 and electronic equipment 404 without CDU 400.

[0036] In an embodiment, the cooling system 100 includes a first valve 116a configured to control the flow of refrigerant to the first heat exchanger 112 and a second valve 116b configured to control the flow of refrigerant to the second heat exchanger 120. In an embodiment, the cooling system 100 also includes one or more pumps 408a to 408c. For example, the cooling system 100 may include a first pump 408a configured to circulate the refrigerant and one or more second pumps 408b, 408c configured to circulate a secondary fluid through the second heat exchanger 120, the electronic devices 404 (e.g., to computer chips within a server), and / or the CDU 400. The cooling system 100 may also include one or more check valves 412a, 412b configured to prevent backflow of the refrigerant. The pumps 408a to 408c and the check valves 112a, 112b may be part of a supplemental heating system that increases the efficiency of the system 100. For example, the pump and check valves may facilitate circulation of the refrigerant without the use of one or more compressors 104. For example, when the outside temperature is below the saturation temperature of the refrigerant, the system 100 may rely on the pump and check valves to circulate the refrigerant in the absence of a compressor, thereby reducing the power consumed to circulate the refrigerant.

[0037] In an embodiment, a portion of the cooling system 100 may be physically located within a server environment 420 (e.g., the location of servers or other electronic devices 404 (a data center)). For example, the CDU 400 and the electronic devices 404 being cooled may be located within the server environment 420. In another example, the CDU 400, the electronic devices 404, and the second heat exchanger 120 may be located within the server environment. In another example, the electronic devices 404 are within the server environment 420.

[0038] Figures 5 to 7 A more detailed schematic diagram of the cooling system 100 is shown operating under different conditions. Figures 5 to 7A cooling system 100 is shown having one or more compressors 104a, 104b, one or more condensers 108a, 108b (e.g., multiple condenser coils), one or more first heat exchangers 112a, 112b (e.g., multiple evaporator coils), and multiple valves 116a to 116d (e.g., first heat exchanger valves 116a to 116b and second heat exchanger valves 116c to 116d). The cooling system 100 can include any number of compressors 104, condensers 108, first heat exchangers 112a, 112b, and second heat exchangers 120. The cooling system 100 can include multiple primary refrigerant circulation loops 500a, 500b. The system can also include one or more secondary cooling loops 502. For example, one or more cooling circuits 102 of the cooling system 100 can include two secondary cooling loops 502 or be in fluid communication with two secondary cooling loops 502.

[0039] Figure 5 The cooling system 100 is shown operating in a first operating mode in which cooling occurs via the air cooling circuit and the first heat exchangers 112a, 112b. In this configuration, the first heat exchanger valves 116a, 116b are open (e.g., as indicated by white valve icons) and the second heat exchanger valves 116c, 116d are closed (e.g., as indicated by black valve icons), thereby allowing refrigerant to circulate through one or more first heat exchangers 112a, 112b and preventing refrigerant from circulating through the second heat exchanger 120. Figures 5 to 7 In the diagram, circulation regions are indicated by arrows, while no-flow regions are indicated by "x".

[0040] Figure 6 The cooling system 100 is shown operating in a second operating mode in which the cooling is liquid cooling performed by the second heat exchanger 120. In this operating mode, the first heat exchanger valves 116a, 116b are closed, while the second heat exchanger valves 116c, 116d are open, thereby allowing the refrigerant to circulate through the second heat exchanger 120 and preventing the refrigerant from circulating through one or more of the first heat exchangers 112a, 112b. Circulation areas are again indicated by arrows, while no-flow areas are indicated by "x."

[0041] Figure 7The cooling system 100 is shown operating in a third operating mode, in which cooling is provided by both an air cooling circuit via one or more first heat exchangers 112a, 112b and a liquid cooling circuit via a second heat exchanger 120 (e.g., in any predefined ratio). In this configuration, one of the first heat exchanger valves, 116a, is closed and the other first heat exchanger valve 116b is open, while one of the second heat exchanger valves, 116c, is closed and the other second heat exchanger valve 116d is open, thereby allowing the refrigerant to be cooled by both the air medium and the liquid medium. The cooling system 100 can be configured to control the cooling ratio of each of the air cooling circuit and the liquid cooling circuit by controlling the flow of refrigerant to the one or more first heat exchangers 112 and the second heat exchanger 120.

[0042] Figure 8 1 is a system diagram illustrating a plurality of cooling circuits 102a through 102c. Depending on the application, the cooling system 100 may include any number of cooling circuits 102a through 102c, including but not limited to a single cooling circuit 102a, two cooling circuits 102a and 102b, three cooling circuits 102a through 102c, ten cooling circuits, thirty cooling circuits, n cooling circuits 102, and the like. For example, the cooling system 100 may include up to thirty-two cooling circuits. The cooling circuits 102a through 102c may be in fluid communication with any number of CDUs 400 or electronic devices 404 (e.g., servers) and may be organized in parallel with a group of CDUs 400 or electronic devices 404.

[0043] In an embodiment, the one or more processors 204 are configured to receive instructions regarding the operating mode of the system 100. For example, the instructions may include controlling the open or closed state of the valve 116 of one or more cooling circuits 102 (e.g., an open instruction and a close instruction). The one or more processors 204 may also be configured to send signals to the valve 116 based on the instructions for each of the cooling circuits. For example, for a cooling system 100 including ten cooling circuits 102, the cooling system 100 may be instructed and executed by the one or more processors 204 of the controller 200 to operate the valve 116 so that some of the cooling circuits 102 operate in a first operating mode for air cooling, while some of the cooling circuits 102 operate in a second operating mode for liquid cooling. Thus, within the cooling system, each of the cooling circuits 102 can be independently controlled.

[0044] Figure 9is a schematic illustration of a cooling system implemented as a hybrid air / liquid unit 900. In embodiments, the hybrid air / liquid unit 900 may be self-contained and positioned relative to the electronic equipment housed in the data center. In embodiments, the hybrid air / liquid unit 900 may include one or more cabinets 902, each of which defines one or more interior spaces for containing cooling system components. The illustrated interior spaces and system component arrangements may vary. For example, the hybrid air / liquid unit 900 may include a condenser 108, an electrical cabinet 906, a compressor compartment 910, one or more first heat exchangers 112 associated with an air cooling circuit, one or more second heat exchangers 120 associated with a liquid cooling circuit, and a pump 408 associated with the liquid cooling circuit. In embodiments, one or more of the interior spaces may be confined spaces. In embodiments, one or more fans 904 (e.g., blowers) are disposed within the unit and associated with the air cooling circuit. In use, one or more fans 904 operate to draw air into the unit 900 and pass the air through the one or more first exchangers 112, as discussed below.

[0045] Figure 10 9. The flow of air through the mixed air / liquid unit 900 is shown via the action of one or more fans 904. In an embodiment, when the one or more fans 904 are energized, "hot" air from the environment is drawn in through a first (e.g., upper) portion of the unit. The "hot" air drawn into the unit by the one or more fans 904 is directed through one or more first heat exchangers 112 associated with the air cooling circuit, whereby the heat is absorbed by the refrigerant, and the resulting cool air is directed out through a second (e.g., lower) portion of the unit, directed toward the electronic equipment to be cooled. When the cooling system 100 is operating in a first operating mode corresponding to air cooling, the one or more fans are energized and can run continuously to direct air through the unit 900, as shown.

[0046] In conventional hybrid systems operating in liquid cooling mode, one or more fans 904 associated with the air cooling circuit are typically de-energized. According to the present disclosure, when operating the cooling system 100 in a second operating mode corresponding to liquid cooling, the one or more fans 904 associated with the air cooling circuit can be cycled "on" and "off" as needed to exhaust "hot" air from within the unit 900, for example, from a confined space within the unit 900. More specifically, when operating in the second operating mode, in which the air cooling circuit is inoperative, liquid cooling is achieved via the second heat exchanger 120 associated with the liquid cooling circuit. When the liquid cooling circuit is operational, one or more pumps 408 associated with the liquid cooling circuit are energized to circulate the liquid medium to the electronic equipment and / or CDU 400. When the pumps 408 are energized, the electric motors associated with the pumps generate heat. Due to the placement of the pumps 408 and motors within the unit 900, and in some cases within the confined space, the heat generated by the operating electric motors can cause the air temperature within the unit 900 to increase. Over time, when the liquid cooling loop is operational, heat may build up within unit 900 to a temperature that may cause damage to system components, such as electrical components housed within unit 900. In such circumstances, it may be necessary to exhaust hot air from within unit 900 to maintain an acceptable air temperature within unit 900.

[0047] In an embodiment, the unit 900 may include one or more temperature sensors 908 configured to sense the internal air temperature within the unit 900. The one or more temperature sensors 908 may be located in predetermined areas within the unit 900, such as near the pump 408, the one or more first heat exchangers 112, the one or more fans 904, electronic components, etc. In use, the one or more temperature sensors 908 are configured to output temperature data to the controller 200, whereby the temperature data is received, processed, and used by the controller 200 to cycle the one or more fans 904 "on" and "off" as needed to exhaust the "hot" air within the unit 900.

[0048] Figure 11A temperature control scheme / method 1100 for managing unit temperature is shown. In step 1102, the controller 200 is configured to determine, based on data received from one or more temperature sensors 908, whether the internal air temperature in the unit exceeds a predefined threshold air temperature while the cooling system 100 is operating in a second operating mode corresponding to liquid cooling. In step 1104, if the internal air temperature is determined to be below the predefined threshold temperature, the second operating mode is maintained without energizing one or more fans 904 associated with the air cooling circuit. In step 1106, if the internal air temperature is determined to be above the threshold temperature, the one or more fans 904 are energized for a predetermined period of time to exhaust air within the unit 900.

[0049] In an embodiment, one or more fans 904 within the unit may be of a type having sensitive contacts that are susceptible to damage from repeated cycles of "on" and "off" and short duration operation. Thus, the period of time during which the one or more fans 904 are energized may be several consecutive minutes to ensure that the "hot" air within the unit has been exhausted and the air temperature has returned to a safe operating temperature (e.g., below a threshold temperature). For example, the predefined time period may be 5 minutes, 10 minutes, 15 minutes, etc. In an embodiment, in the case of one or more fans 904 with variable speed, the one or more fans 904 may be operated at a low or minimum speed during a second operating mode corresponding to liquid cooling, so that a minimum volume of hot air is directed toward the electronic equipment to be cooled by the liquid cooling circuit. In other words, given that hot air may be exhausted through an outlet corresponding to the air cooling circuit, it is desirable to minimize air flow during the unit cooling operating mode.

[0050] Continuing with method 1100, in step 1108, the controller 200 determines, based on one or more sensors 908, whether the air temperature within the unit 900 has dropped below a predefined threshold temperature, and in some embodiments, by a predefined amount. In step 1108, the temperature determination can be made while one or more fans 904 are operating, for example, near the end of a predefined time period (e.g., 8 or 9 minutes in the case of a 10-minute time period). In step 1110, if it is determined that the air temperature within the unit 900 has dropped below the predefined temperature threshold, the one or more fans 904 can be powered off at the end of the predefined time period. In step 1112, if it is determined that the air temperature within the unit 900 has not sufficiently dropped below the predefined threshold temperature, the one or more fans 904 can continue to operate continuously for another predefined time period to avoid having to power one or more fans 904 off and then on two or more times.

[0051] In an embodiment, the one or more processors 204 of the controller 200 may be implemented as any suitable processor configured to execute instructions for performing (e.g., collectively if there is more than one processor) any or all of the operations disclosed herein, such as at least one general purpose processor, at least one central processing unit (CPU), at least one image processor, at least one graphics processing unit (GPU), at least one field programmable gate array (FPGA), and / or at least one special purpose processor.

[0052] Those skilled in the art will recognize that the state of the art has advanced to the point where there is little distinction between hardware and software implementations of various aspects of a system; the use of hardware or software is often (but not always, as the choice between hardware and software can become important in certain contexts) a design choice that represents a trade-off between cost and efficiency. Those skilled in the art will understand that there are a variety of tools (e.g., hardware, software, and / or firmware) by which the processes and / or systems and / or other techniques described herein can be implemented, and that the preferred tool will vary depending on the context in which the processes and / or systems and / or other techniques are deployed. For example, if an implementer determines that speed and accuracy are most important, the implementer may choose a primarily hardware and / or firmware tool; alternatively, if flexibility is most important, the implementer may choose a primarily software implementation; or, again alternatively, the implementer may choose some combination of hardware, software, and / or firmware. Thus, there are several possible tools by which the processes and / or devices and / or other techniques described herein can be implemented, with no one tool being inherently superior to another, as the choice of any tool to be utilized is a choice that depends on the context in which the tool will be deployed and the implementer's specific concerns (e.g., speed, flexibility, or predictability), any of which can vary.

[0053] The foregoing detailed description has been described using block diagrams, flow charts and / or examples to illustrate various embodiments of the device and / or process. To the extent that such block diagrams, flow charts and / or examples include one or more functions and / or operations, it will be understood by those skilled in the art that each function and / or operation in such block diagrams, flow charts or examples can be implemented individually and / or collectively by various hardware, software, firmware or any combination thereof. In one embodiment, several parts of the subject matter described herein can be implemented via application specific integrated circuits (ASICs), field programmable gate arrays (FPGAs), digital signal processors (DSPs) or other integrated formats. However, it will be appreciated by those skilled in the art that some aspects of the embodiments disclosed herein can be implemented in whole or in part in an integrated circuit as one or more computer programs running on one or more computers (e.g., as one or more programs running on one or more computer systems), as one or more programs running on one or more processors (e.g., as one or more programs running on one or more microprocessors), as firmware, or in fact as any combination thereof, and that designing circuit systems and / or writing code for software and / or firmware will be entirely within the skill of those skilled in the art based on the present disclosure. In addition, those skilled in the art will appreciate that the mechanisms of the subject matter described herein can be distributed as a program product in a variety of forms, and that the illustrative embodiments of the subject matter described herein apply regardless of the particular type of signal-bearing medium used to actually perform the distribution. Examples of signal-bearing media include, but are not limited to, recordable media such as floppy disks, hard drives, compact disks (CDs), digital video disks (DVDs), digital tapes, computer memories, and the like; and transmission media such as digital and / or analog communication media (e.g., fiber optic cables, waveguides, wired communication links, wireless communication links, and the like).

[0054] In a general sense, those skilled in the art will recognize that the various aspects described herein, which may be implemented individually and / or collectively by a wide range of hardware, software, firmware, or any combination thereof, may be considered to include various types of "circuitry." Thus, as used herein, "circuitry" includes, but is not limited to, circuitry having at least one discrete circuit, circuitry having at least one integrated circuit, circuitry having at least one application-specific integrated circuit, circuitry forming a general-purpose computing device configured by a computer program (e.g., a general-purpose computer configured by a computer program that at least partially performs the processes and / or devices described herein or a microprocessor configured by a computer program that at least partially performs the processes and / or devices described herein), circuitry forming a storage device (e.g., in the form of random access memory), and / or circuitry forming a communication device (e.g., a modem, a communications switch, or an optoelectronic device). Those skilled in the art will recognize that the subject matter described herein may be implemented in an analog or digital manner, or some combination thereof.

[0055] Those skilled in the art will recognize that it is common in the art to describe devices and / or processes in the manner set forth herein and thereafter use engineering practices to integrate such described devices and / or processes into data processing systems. That is, at least a portion of the devices and / or processes described herein can be integrated into data processing systems via a reasonable amount of experimentation. Those skilled in the art will recognize that a typical data processing system typically includes one or more of the following: a system unit housing, a video display device, memory such as volatile and non-volatile memory, a processor such as a microprocessor and a digital signal processor, a computing entity such as an operating system, a driver, a graphical user interface, and an application program, one or more interactive devices such as a touchpad or screen, and / or a control system including feedback loops and control motors (e.g., feedback for sensing position and / or velocity; control motors for moving and / or adjusting components and / or quantities). A typical data processing system can be implemented using any suitable commercially available components, such as those typically found in data computing / communication and / or network computing / communication systems.

[0056] As used throughout and as will be understood by one skilled in the art, “at least one non-transitory computer-readable medium” or “memory 208” may refer to at least one non-transitory computer-readable medium (such as, for example, at least one computer-readable medium implemented as hardware; for example, at least one non-transitory processor-readable medium, at least one memory (e.g., at least one non-volatile memory, at least one volatile memory, or a combination thereof; for example, at least one random access memory, at least one flash memory, at least one read-only memory (ROM) (e.g., at least one electrically erasable programmable read-only memory (EEPROM))), at least one on-processor memory (e.g., at least one on-processor cache, at least one on-processor buffer, at least one on-processor flash memory, at least one on-processor EEPROM, or a combination thereof), or a combination thereof), at least one storage device (e.g., at least one hard drive, at least one tape drive, at least one solid-state drive, at least one flash drive, at least one readable disk and / or writable disk of at least one optical drive configured to read from at least one readable disk and / or write to at least one writable disk, or a combination thereof), or a combination thereof).

[0057] The subject matter described herein sometimes shows different components contained within or connected to different other components. It should be understood that the architectures depicted in this manner are merely exemplary and that many other architectures that implement the same functionality can actually be implemented. In a conceptual sense, any arrangement of components that implement the same functionality is effectively "associated" to achieve the desired functionality. Therefore, any two components that are combined herein to achieve a particular functionality can be considered to be "associated" with each other so as to achieve the desired functionality, regardless of the architecture or intermediate components. Similarly, any two components that are so associated can also be considered to be "operably connected" or "operably coupled" to each other to achieve the desired functionality, and any two components that can be so associated can also be considered to be "operably coupled" to each other to achieve the desired functionality. Specific examples of components that can be operably coupled include, but are not limited to, components that can be physically matched and / or physically interacted and / or components that can wirelessly interact and / or wirelessly interact and / or components that can logically interact and / or components that can logically interact.

[0058] While particular aspects of the subject matter described herein have been shown and described, it will be apparent to those skilled in the art that, based on the teachings herein, changes and modifications may be made without departing from the subject matter described herein and its broader aspects, and, therefore, the appended claims are intended to include within their scope all such changes and modifications as are within the true spirit and scope of the subject matter described herein. Furthermore, it should be understood that the invention is defined by the appended claims.

Claims

1. A cooling system comprising: Refrigerant circuit; an air cooling circuit in fluid communication with the refrigerant circuit, the air cooling circuit comprising at least one first heat exchanger and at least one fan configured to flow air through the at least one first heat exchanger; a liquid cooling circuit in fluid communication with the refrigerant circuit, the liquid cooling circuit comprising at least one second heat exchanger and at least one pump; a valve assembly configured to selectively direct refrigerant flow to at least one of the air cooling circuit and the liquid cooling circuit; as well as a controller communicatively coupled to the valve assembly and the at least one fan, the controller comprising one or more processors configured to: operating the cooling system in a first operating mode in which the air cooling circuit is operable and the liquid cooling circuit is inoperable; as well as The cooling system is operated in a second operating mode in which the air cooling circuit is inoperable, the liquid cooling circuit is operable, and the at least one fan of the air cooling circuit is selectively operable to cool at least a portion of the cooling system.

2. The cooling system according to claim 1, further comprising: at least one cabinet containing at least a portion of each of the refrigerant circuit, the air cooling circuit, the liquid cooling circuit, and the valve assembly; as well as at least one temperature sensor disposed in the at least one cabinet, the at least one temperature sensor configured to sense an internal air temperature in the at least one cabinet; wherein the controller is communicatively coupled to the at least one temperature sensor and is further configured to: When the cooling system operates in the second operating mode, the at least one fan of the air cooling circuit is energized when the internal air temperature in the at least one cabinet exceeds a predefined threshold air temperature.

3. The cooling system according to claim 2, wherein: The at least one fan of the air cooling circuit is energized for a predefined period of time.

4. The cooling system according to claim 3, wherein: The controller is further configured to: determining, based on the at least one temperature sensor, whether an internal air temperature in the at least one cabinet has dropped below the predefined threshold air temperature while the at least one fan is powered on for the predefined period of time; and de-energizing the at least one fan if the internal air temperature in the at least one cabinet is determined to have dropped below the predefined threshold air temperature; as well as If the internal air temperature in the at least one cabinet is determined not to have dropped below the predefined threshold air temperature, the at least one fan is maintained energized for another continuous predefined time period.

5. The cooling system according to claim 1, wherein: The at least one first heat exchanger includes an evaporator coil.

6. The cooling system according to claim 1, wherein: The at least one second heat exchanger comprises a brazed plate heat exchanger BPHE.

7. The cooling system according to claim 2, wherein: The cabinet does not include dedicated exhaust fans.

8. A hybrid air / liquid cooling unit comprising: A cabinet with a defined interior space; a refrigerant circuit contained within the interior space; an air cooling circuit contained within the interior space and in fluid communication with the refrigerant circuit, the air cooling circuit comprising at least one first heat exchanger and at least one fan configured to flow air through the at least one first heat exchanger; a liquid cooling circuit contained within the interior space and in fluid communication with the refrigerant circuit, the liquid cooling circuit comprising at least one second heat exchanger and at least one pump; a valve assembly contained within the interior space and configured to selectively direct refrigerant flow to at least one of the air cooling circuit and the liquid cooling circuit; as well as a controller communicatively coupled to the valve assembly and the at least one fan, the controller comprising one or more processors configured to: operating the hybrid air / liquid cooling unit in a first operating mode in which the air cooling circuit is operable and the liquid cooling circuit is inoperable; as well as The hybrid air / liquid cooling unit is operated in a second operating mode in which the air cooling circuit is inoperable, the liquid cooling circuit is operable, and the at least one fan is selectively operable to exhaust air from the interior space.

9. The hybrid air / liquid cooling unit of claim 8, further comprising: at least one temperature sensor disposed in the interior space, the at least one temperature sensor configured to sense an interior air temperature in the interior space; wherein the controller is communicatively coupled to the at least one temperature sensor and is further configured to: When the hybrid air / liquid cooling unit is operating in the second operating mode, the at least one fan is energized when an interior air temperature in the interior space exceeds a predefined threshold air temperature.

10. The hybrid air / liquid cooling unit of claim 9, wherein: The at least one fan is powered on for a predefined period of time.

11. The hybrid air / liquid cooling unit of claim 10, wherein: The controller is further configured to: determining, based on the at least one temperature sensor, whether an interior air temperature in the interior space has dropped below the predefined threshold air temperature while the at least one fan is powered on for the predefined period of time; and de-energizing the at least one fan if the interior air temperature in the interior space is determined to have dropped below the predefined threshold air temperature; as well as If the interior air temperature in the interior space is determined not to have dropped below the predefined threshold air temperature, the at least one fan is maintained energized for another continuous predefined time period.

12. The hybrid air / liquid cooling unit of claim 8, wherein: The at least one first heat exchanger includes an evaporator coil.

13. The hybrid air / liquid cooling unit of claim 8, wherein: The at least one second heat exchanger comprises a brazed plate heat exchanger BPHE.

14. The hybrid air / liquid cooling unit of claim 8, wherein: The cabinet does not include dedicated exhaust fans.

15. A method for controlling a hybrid air / liquid cooling unit, the method comprising: Providing: a cabinet defining an interior space; a refrigerant circuit contained in the interior space; an air cooling circuit contained within the interior space and in fluid communication with the refrigerant circuit, the air cooling circuit comprising at least one first heat exchanger and at least one fan configured to flow air through the at least one first heat exchanger; a liquid cooling circuit contained within the interior space and in fluid communication with the refrigerant circuit, the liquid cooling circuit comprising at least one second heat exchanger and at least one pump; and a valve assembly contained within the interior space and configured to selectively flow refrigerant to at least one of the air cooling circuit and the liquid cooling circuit; providing a controller communicatively coupled to the valve assembly and the at least one fan, the controller comprising one or more processors; operating, by the controller, the hybrid air / liquid cooling unit in a first operating mode in which the air cooling circuit is operable and the liquid cooling circuit is inoperable; as well as The hybrid air / liquid cooling unit is operated by the controller in a second operating mode in which the air cooling circuit is inoperable, the liquid cooling circuit is operable, and the at least one fan is selectively operable to exhaust air from the interior space.

16. The method according to claim 15, further comprising: providing at least one temperature sensor disposed in the interior space, the at least one temperature sensor configured to sense an interior air temperature in the interior space, wherein the controller is communicatively coupled to the at least one temperature sensor; and When the hybrid air / liquid cooling unit is operating in the second operating mode, the at least one fan is energized by the controller when an interior air temperature in the interior space exceeds a predefined threshold air temperature.

17. The method according to claim 16, wherein The at least one fan is powered on for a predefined period of time.

18. The method according to claim 17, further comprising: determining, by the controller based on the at least one temperature sensor, whether an interior air temperature in the interior space has dropped below the predefined threshold air temperature when the at least one fan is powered on for the predefined period of time; and de-energizing the at least one fan if the interior air temperature in the interior space is determined by the controller to have dropped below the predefined threshold air temperature; as well as If the interior air temperature in the interior space is determined by the controller to have not fallen below the predefined threshold air temperature, the at least one fan is maintained energized for another continuous predefined time period.

19. The method according to claim 15, wherein The at least one first heat exchanger comprises an evaporator coil, and the at least one second heat exchanger comprises a brazed plate heat exchanger (BPHE).

20. The method according to claim 15, wherein The cabinet does not include dedicated exhaust fans.

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