System comprising a compressor, an expansion valve, heat exchangers, and a check valve, and associated method

Abstract

A heat exchanger system can include a first heat exchanger configured to exchange heat from a single-phase cooling fluid to a two-phase cooling fluid, a compressor in fluid communication with the first heat exchanger and configured to compress the two-phase cooling fluid received in gaseous form from the first heat exchanger, a second heat exchanger in fluid communication with the compressor and configured to condense the two-phase cooling fluid received from the compressor, a pump in fluid communication between the first heat exchanger and the second heat exchanger, a check valve in fluid communication between the first heat exchanger and the pump, or any combination thereof. The check valve can trap the portion of the two-phase cooling fluid between the check valve and the compressor or an expansion valve, when the system is stopped.

Description

SYSTEM COMPRISING A COMPRESSOR, AN EXPANSION VALVE, HEAT EXCHANGERS, AND A CHECK VALVE, AND ASSOCIATED METHODCROSS REFERENCE TO RELATED APPLICATIONS

[0001] This application claims the benefit of U.S. Provisional Patent Application No. 63 / 604,177 filed November 29, 2023, the entire contents of which are incorporated herein by reference.TECHNICAL FIELD

[0002] The present disclosure relates generally to heat exchanger systems and more specifically relates to split cooling systems used in cold environments.BACKGROUND

[0003] Some cooling applications utilize split systems, such as where a refrigerant-based cooling system is used to cool a water-based cooling system. In such systems, undesired heat is typically extracted by the water-based cooling system and then exchanged to the refrigerant-based cooling system, where it is typically discharged into the environment. The heat exchangers between these systems may therefore have both refrigerant and water flowing through them.

[0004] A problem arises where portions of the refrigerant-based cooling system are located in especially cold environments. In this case, the refrigerant entering the heat exchanger, between the water-based cooling system and the refrigerant-based cooling system, can be so cold as to cause the water therein to freeze, causing damage to the heat exchanger and incurring expensive repair and clean-up costs.

[0005] A refrigerant-to-water plate heat exchanger is often used in split systems to achieve the highest heat transfer possible. During cold outdoor conditions, a split system starts up at low system pressure and will create an even lower suction pressure in the heat exchanger, between the water-based coolingsystem and the refrigerant-based cooling system. Further, it sends refrigerant that is at the outdoor temperature directly into the heat exchanger. With the low suction pressure and extremely cold refrigerant, water can freeze rapidly at an internal location of the heat exchanger. Given enough temperature difference and time in these conditions, this can create a localized ice dam and / or crack the thin metal plate inside the heat exchanger. This results in the water and refrigerant sides mixing, bringing that system down for an extended time period and requiring an expensive repair.SUMMARY

[0006] Applicant has created new and useful devices, systems and methods for split cooling systems used in cold environments. In at least one embodiment, a split cooling system according to the disclosure can advantageously provide for improved suction pressure and refrigerant temperature characteristics which, in turn, can advantageously allow for the use of water in secondary cooling loops of systems utilized in geographic locations with relatively low outdoor temperatures. More specifically, in one or more embodiments of the disclosure, a portion of refrigerant circulated through a primary cooling loop can be trapped or otherwise maintained at a relatively warmer temperature and / or higher pressure as compared to a portion of the refrigerant exposed to an outdoor ambient temperature (e.g., during system shutdown or standby). For instance, upon system shut down, a portion of the refrigerant can be maintained within plumbing disposed in a building or other temperature-controlled environment, while other portions of the refrigerant may be exposed to relatively low outdoor temperatures that could be problematic upon startup of a system utilizing water circulated through one or more evaporators (e.g., brazed plate heat exchangers) in the secondary cooling loop. In this manner, a volume of relatively warm refrigerant at a relatively higher pressure can be available at system startup for release or injection into the primary loopside of the evaporator to aid in freeze prevention of water circulated through the secondary loop side of the evaporator.

[0007] In other words, by releasing relatively warm, high-pressure refrigerant into the evaporator at startup, suction pressure and evaporator temperature can be increased when the compressor starts, thereby guarding against freezing of water within the evaporator and creating more favorable differential pressure conditions for the compressor. The higher starting pressure can also more closely match what the compressor would see under higher outdoor temperature conditions and can allow the compressor to establish an appropriate differential pressure more quickly. Similarly, it can create a higher pressure at the pump inlet, which can also be beneficial upon a cold start. If required or desired for a given implementation of the disclosure, one or more valves can be utilized to relieve excess pressure from one portion of the primary loop to another and / or for maintaining a desired pressure of the relatively warm, high-pressure refrigerant “trapped” within the relevant plumbing upon shutdown.

[0008] In at least one embodiment, a split cooling system according to the disclosure can include a first heat exchanger configured to exchange heat from a single-phase cooling fluid to a two-phase cooling fluid, a compressor in fluid communication with the first heat exchanger and configured to compress the two- phase cooling fluid received in gaseous form from the first heat exchanger, a second heat exchanger in fluid communication with the compressor and configured to condense the two-phase cooling fluid received from the compressor, a pump in fluid communication between the first heat exchanger and the second heat exchanger, a check valve in fluid communication between the first heat exchanger and the pump, or any combination thereof. In at least one embodiment, the check valve can trap a portion of the two-phase cooling fluid between the check valve and the compressor, such as when the compressor isstopped. In at least one embodiment, the system can include an expansion valve, such as between the check valve and the first heat exchanger. In at least one embodiment, the check valve can trap a portion of the two-phase cooling fluid between the check valve and the expansion valve, such as when the expansion valve closes.

[0009] In at least one embodiment, the first heat exchanger and / or the compressor can be disposed within a building and exposed to an internal temperature within the building. In at least one embodiment, the second heat exchanger and / or the pump can be disposed outside the building and exposed to an external temperature outside the building. In at least one embodiment, the external temperature is expected to be well below the internal temperature and / or the freezing point of the single-phase cooling fluid, at least some of the time. In at least one embodiment, the check valve can be disposed within the building. In at least one embodiment, the check valve can contain, such as when the compressor is stopped, a portion of the two-phase cooling fluid within the building, such that the portion of the two-phase cooling fluid is exposed to the internal temperature within the building.

[0010] In at least one embodiment, the system can include a pressure relief valve plumbed between the check valve and the first heat exchanger. In at least one embodiment, the system can include a pressure relief valve plumbed in parallel with the check valve.

[0011] In at least one embodiment, a split cooling system according to the disclosure can include a first heat exchanger configured to exchange heat from a single-phase cooling fluid to a two-phase cooling fluid, a compressor in fluid communication with the first heat exchanger and configured to compress the two- phase cooling fluid received in gaseous form from the first heat exchanger, a second heat exchanger in fluid communication with the compressor andconfigured to condense the two-phase cooling fluid received from the compressor, a check valve in fluid communication with the first heat exchanger and / or the second heat exchanger, or any combination thereof. In at least one embodiment, the check valve can contain, such as when the compressor is stopped, a portion of the two-phase cooling fluid between the check valve and the compressor.

[0012] In at least one embodiment, the system can include an expansion valve. In at least one embodiment, the check valve can trap the portion of the two-phase cooling fluid between the check valve and the expansion valve, such as when the expansion valve closes. In at least one embodiment, the expansion valve and / or the check valve can be disposed within a building. In at least one embodiment, a portion of the two-phase cooling fluid can be exposed to an internal temperature within the building when trapped between the check valve and the expansion valve. In at least one embodiment, the compressor and the check valve can be disposed within a building. In at least one embodiment, a portion of the two-phase cooling fluid can be exposed to an internal temperature within the building when contained between the check valve and the compressor.

[0013] In at least one embodiment, the system can include a pressure relief valve plumbed between the check valve and the first heat exchanger. In at least one embodiment, the system can include a pressure relief valve plumbed in parallel with the check valve.

[0014] In at least one embodiment, a heat rejection method according to the disclosure can include passing a single-phase cooling fluid and a two-phase cooling fluid through a first heat exchanger, thereby transferring heat from the single-phase cooling fluid to the two-phase cooling fluid, compressing the two- phase cooling fluid exiting the first heat exchanger, passing the two-phase cooling fluid through a second heat exchanger, thereby rejecting heat from the two-phasecooling fluid, pumping the two-phase cooling fluid through a check valve and an expansion valve, closing the expansion valve, thereby trapping a portion of the two-phase cooling fluid between the check valve and the expansion valve, or any combination thereof. In at least one embodiment, the compressing can be done using a compressor and / or a pump. In at least one embodiment, the pumping can be done using a compressor and / or a pump.

[0015] In at least one embodiment, the method can include stopping the pump and the compressor after closing the expansion valve. In at least one embodiment, the method can include stopping the pump after closing the expansion valve and / or stopping the compressor after stopping the pump. In at least one embodiment, the method can include stopping the compressor after closing the expansion valve and / or stopping the pump after stopping the compressor.

[0016] In at least one embodiment, the method can include opening the expansion valve, starting the compressor after opening the expansion valve, and starting the pump after starting the compressor. In at least one embodiment, the method can include opening the expansion valve, starting the pump after opening the expansion valve, and starting the compressor after starting the pump.BRIEF DESCRIPTION OF THE DRAWINGS

[0017] FIG. 1 is a simplified schematic of one of many embodiments of a split cooling system according to the disclosure.

[0018] FIG. 2 is a graph showing start up conditions of one of many embodiments of a split cooling system without a check valve according to the disclosure.

[0019] FIG. 3 is a graph showing start up conditions of one of many embodiments of a split cooling system with a check valve according to the disclosure.DETAILED DESCRIPTION

[0020] The figures described above and the written description of specific structures and functions below are not presented to limit the scope of what Applicant has invented or the scope of the appended claims. Rather, the figures and written description are provided to teach any person skilled in the art to make and use the inventions for which patent protection is sought. Those skilled in the art will appreciate that not all features of a commercial embodiment of the inventions are described or shown for the sake of clarity and understanding. Persons of skill in this art will also appreciate that the development of an actual commercial embodiment incorporating aspects of the present inventions will require numerous implementation-specific decisions to achieve the developer’s ultimate goal for the commercial embodiment. Such implementation-specific decisions may include, and likely are not limited to, compliance with system- related, business-related, government-related and other constraints, which may vary by specific implementation, location and from time to time. While a developer’s efforts might be complex and time-consuming in an absolute sense, such efforts would be, nevertheless, a routine undertaking for those of skill in this art having benefit of this disclosure. It must be understood that the inventions disclosed and taught herein are susceptible to numerous and various modifications and alternative forms.

[0021] The use of a singular term, such as, but not limited to, “a,” is not intended as limiting of the number of items. Also, the use of relational terms, such as, but not limited to, “top,” “bottom,” “left,” “right,” “upper,” “lower,” “down,” “up,” “side,” and the like are used in the written description for clarity in specificreference to the figures and are not intended to limit the scope of the inventions or the appended claims. The terms “including” and “such as” are illustrative and not limitative. The terms “couple,” “coupled,” “coupling,” “coupler,” and like terms are used broadly herein and can include any method or device for securing, binding, bonding, fastening, attaching, joining, inserting therein, forming thereon or therein, communicating, or otherwise associating, for example, mechanically, magnetically, electrically, chemically, operably, directly or indirectly with intermediate elements, one or more pieces of members together and can further include without limitation integrally forming one functional member with another in a unity fashion. The coupling can occur in any direction, including rotationally. Further, all parts and components of the disclosure that are capable of being physically embodied inherently include imaginary and real characteristics regardless of whether such characteristics are expressly described herein, including but not limited to characteristics such as axes, ends, inner and outer surfaces, interior spaces, tops, bottoms, sides, boundaries, dimensions (e.g., height, length, width, thickness), mass, weight, volume and density, among others.

[0022] Applicant has created new and useful devices, systems and methods for heat exchanger systems used in cold environments. In at least one embodiment, a split cooling system according to the disclosure can advantageously provide for improved suction pressure and refrigerant temperature characteristics which, in turn, can advantageously allow for the use of water in secondary cooling loops of systems utilized in geographic locations with relatively low outdoor temperatures. More specifically, in one or more embodiments of the disclosure, a portion of refrigerant circulated through a primary cooling loop can be trapped or otherwise maintained at a relatively warmer temperature and / or higher pressure as compared to a portion of the refrigerant exposed to an outdoor ambient temperature (e.g., during systemshutdown or standby). For instance, upon system shut down, a portion of the refrigerant can be maintained within plumbing disposed in a building or other temperature-controlled environment, while other portions of the refrigerant may be exposed to relatively low outdoor temperatures that could be problematic upon startup of a system utilizing water circulated through one or more evaporators (e.g., brazed plate heat exchangers) in the secondary cooling loop. In this manner, a volume of relatively warm refrigerant at a relatively higher pressure can be available at system startup for release or injection into the primary loop side of the evaporator to aid in freeze prevention of water circulated through the secondary loop side of the evaporator.

[0023] In other words, by releasing relatively warm, high-pressure refrigerant into the evaporator at startup, suction pressure and evaporator temperature can be increased when the compressor starts, thereby guarding against freezing of water within the evaporator and creating more favorable differential pressure conditions for the compressor. The higher starting pressure can also more closely match what the compressor would see under higher outdoor temperature conditions and can allow the compressor to establish an appropriate differential pressure more quickly. Similarly, it can create a higher pressure at the pump inlet, which can also be beneficial upon a cold start. If required or desired for a given implementation of the disclosure, one or more valves can be utilized to relieve excess pressure from one portion of the primary loop to another and / or for maintaining a desired pressure of the relatively warm, high-pressure refrigerant “trapped” within the relevant plumbing upon shutdown.

[0024] In at least one embodiment, a split cooling system according to the disclosure can accommodate cold weather startups, and the hazards associated therewith, by creating higher suction pressure and warmer refrigerant when an expansion valve opens and / or a compressor starts. In at least one embodiment,a split cooling system according to the disclosure can include one or more heat exchangers configured to exchange heat from a single-phase cooling fluid to a two-phase cooling fluid, a compressor in fluid communication with the heat exchangers, and a check valve in fluid communication with the heat exchangers. In at least one embodiment, the check valve can trap a portion of the two-phase cooling fluid between the check valve and the compressor, such as when the compressor is stopped. In at least one embodiment, the system can include an expansion valve, and the check valve can trap a portion of the two-phase cooling fluid between the check valve and the expansion valve, such as when the expansion valve closes. In at least one embodiment, the check valve can thereby maintain higher suction pressure and warmer refrigerant when the expansion valve opens and / or the compressor starts.

[0025] FIG. 1 is a simplified schematic of one of many embodiments of a split cooling system according to the disclosure. FIG. 2 is a graph showing start up conditions of one of many embodiments of a split cooling system without a check valve according to the disclosure. FIG. 3 is a graph showing start up conditions of one of many embodiments of a split cooling system with a check valve according to the disclosure. FIGS. 1-3 are described in conjunction with one another.

[0026] In at least one embodiment, a split cooling system 100 according to the disclosure can include one or more first heat exchangers 102 configured to exchange heat from a single-phase cooling fluid to a two-phase cooling fluid, one or more compressors 104 in fluid communication with the first heat exchanger 102 and configured to compress the two-phase cooling fluid received in gaseous form from the first heat exchanger 102, one or more second heat exchangers 106 in fluid communication with the compressor 104 and configured to condense the two-phase cooling fluid received from the compressor 104, one or more pumps108 in fluid communication between the first heat exchanger 102 and the second heat exchanger 106, one or more check valves 110 in fluid communication between the first heat exchanger 102 and the pump 108, or any combination thereof. For example, the system 100 can include two or more heat exchangers 102 configured to exchange heat from a single-phase cooling fluid to a two-phase cooling fluid and / or two or more heat exchangers 106 configured to condense the two-phase cooling fluid.

[0027] In at least one embodiment, the single-phase cooling fluid can be water, a water-glycol mixture, or another cooling fluid. In at least one embodiment, the single-phase cooling fluid can be a two-phase cooling fluid that does not actually change phase in a given situation. In at least one embodiment, the two-phase cooling fluid can be a refrigerant or other two-phase cooling fluid.

[0028] In at least one embodiment, the check valve 110 can trap a portion of the two-phase cooling fluid between the check valve and the compressor 104, such as when the compressor 104 is stopped. In at least one embodiment, the system 100 can include one or more expansion valves 112 (e.g., one or more electronic expansion valves (EEVs), such as between the check valve 1 10 and the first heat exchanger 102. In at least one embodiment, the check valve 110 can trap a portion of the two-phase cooling fluid between the check valve and the expansion valve 112, such as when the expansion valve 112 closes. In at least one embodiment, the expansion valve 112 can be used to control the pressure and / or heat exchange within the first heat exchanger 102. In at least one embodiment, the check valve 110 can be or include any type of check valve and / or any type of valve or combination of valves capable of accomplishing the corresponding function(s) described in the present disclosure.

[0029] In at least one embodiment, the first heat exchanger 102 and / or the compressor 104 can be disposed within a building 114 and exposed to an internaltemperature within the building 114. In at least one embodiment, one or more first heat exchangers 102 and / or one or more compressors 104 can be disposed within one building 1 14 and another one or more first heat exchangers 102 and / or another one or more compressors 104 can be disposed within another building 114. In at least one embodiment, the second heat exchanger 106 and / or the pump 108 can be disposed outside the building 114 and exposed to an external temperature outside the building. In at least one embodiment, one second heat exchanger 106 and / or one pump 108 can serve one or more first heat exchangers 102 and / or compressors 104 in one building 114 and another one or more first heat exchangers 102 and / or compressors 104 in another building 114. In at least one embodiment, two or more second heat exchangers 106 and / or two or more pumps 108 can serve one or more first heat exchangers 102 and / or compressors 104 in one building 114. In at least one embodiment, the check valve 110 can be disposed within the building 114. In at least one embodiment, the check valve 110 can contain, such as when the compressor 104 is stopped, a portion of the two-phase cooling fluid within the building 114, such that the portion of the two- phase cooling fluid is exposed to the internal temperature within the building 114.

[0030] In at least one embodiment, the external temperature outside the building 114 is expected to be well below the internal temperature within the building 114 and / or the freezing point of the single-phase cooling fluid, at least some of the time (such as during winter storms). In at least one embodiment, the external temperature outside the building 114 is expected to stay well below the internal temperature within the building 114 and / or the freezing point of the singlephase cooling fluid, such as in extremely cold environments. In at least one embodiment, the external temperature outside the building 114 can be below 32 degrees Fahrenheit. In at least one embodiment, the external temperature outside the building 114 can be below zero degrees Fahrenheit. In at least oneembodiment, the external temperature outside the building 114 can be at or below negative 30 degrees Fahrenheit.

[0031] In at least one embodiment, the system 100 can include one or more pressure relief valves 116 plumbed between the check valve 110 and the first heat exchanger 102. In at least one embodiment, the pressure relief valve 116 can prevent excessive pressure between the check valve 110 and the first heat exchanger 102, such as by venting the two-phase cooling fluid external to the system 100 or to another point in the system. In at least one embodiment, the pressure relief valve 116 can selectively relieve pressure from a liquid return line of the first heat exchanger 102 to the second heat exchanger 106. For example, in at least one embodiment, the system 100 can include one or more pressure relief valves 116 plumbed in parallel with the check valve 110, such that excess pressure between the check valve 110 and the first heat exchanger 102 can be released back towards the second heat exchanger 106 and / or the pump 108. In at least one embodiment, the pressure relief valve 116 can selectively relieve pressure from downstream of the check valve 110 to upstream of the check valve 110.

[0032] In at least one embodiment, the system 100 can create a higher suction pressure and / or warmer two-phase cooling fluid when the expansion valve 112 opens and / or the compressor 104 starts. In at least one embodiment, the system 100 can avoid an extremely low suction pressure and / ortemper a cold two-phase cooling fluid entering the first heat exchanger 102 so it is harmless to the single-phase cooling fluid in the first heat exchanger 102. In at least one embodiment, the system 100 can aid in the compressor 104 starting without a low differential pressure issue and starting in very cold environments. In at least one embodiment, the system 100 can use water as the single-phase cooling fluideven with outdoor temperatures at or below -30F, a temperature that would otherwise freeze the water locally and / or break the first heat exchanger 102.

[0033] In at least one embodiment, the check valve 1 10 can keep a portion of the two-phase cooling fluid from migrating out to a cold second heat exchanger 106 after the system 100 shuts down or moves to a standby condition so the two- phase cooling fluid in that section of piping remains at a higher pressure. In at least one embodiment, when the expansion valve 112 opens and / or the compressor 104 starts, this higher-pressure two-phase cooling fluid enters the first heat exchanger 102 and / or keeps the compressor 104 suction from creating a pressure inside the first heat exchanger 102 below a design threshold. In at least one embodiment, this higher-pressure two-phase cooling fluid can also buffer an incoming cold two-phase cooling fluid temperature with the two-phase cooling fluid that is at the indoor temperature. In at least one embodiment, this higher-pressure two-phase cooling fluid can more closely match what the compressor 104 would see with higher outdoor conditions, allow the compressor 104 to establish the desired differential pressure immediately, create a higher pressure at the PRE pump inlet to do a cold start without issue, or any combination thereof. Due to the possibility of trapped liquid in some scenarios, a pressure relief valve 116 can be used to relieve excess pressure into another portion of the system 100 while maintaining a desired pressure in the trapped section.

[0034] In at least one embodiment, a split cooling system 100 according to the disclosure can include one or more first heat exchangers 102 configured to exchange heat from a single-phase cooling fluid to a two-phase cooling fluid, one or more compressors 104 in fluid communication with the first heat exchanger 102 and configured to compress the two-phase cooling fluid received in gaseous form from the first heat exchanger 102, one or more second heat exchangers 106in fluid communication with the compressor 104 and configured to condense the two-phase cooling fluid received from the compressor 104, one or more check valves 110 in fluid communication with the first heat exchanger 102 and / or the second heat exchanger 106, or any combination thereof. In at least one embodiment, the check valve 110 can contain, such as when the compressor 104 is stopped, a portion of the two-phase cooling fluid between the check valve and the compressor 104.

[0035] In at least one embodiment, the compressor 104 and the check valve 104 can be disposed within a building 114. In at least one embodiment, a portion of the two-phase cooling fluid can be exposed to an internal temperature within the building 114 when contained between the check valve 110 and the compressor 104.

[0036] In at least one embodiment, the system 100 can include one or more expansion valves 112. In at least one embodiment, the check valve 110 can trap the portion of the two-phase cooling fluid between the check valve and the expansion valve 112, such as when the expansion valve 112 closes. In at least one embodiment, the expansion valve 112 and / or the check valve 110 can be disposed within a building 114. In at least one embodiment, a portion of the two- phase cooling fluid can be exposed to an internal temperature within the building 114 when trapped between the check valve 110 and the expansion valve 112.

[0037] In at least one embodiment, the system 100 can include one or more pressure relief valves 116 plumbed between the check valve 110 and the first heat exchanger 102, such as to control the pressure between the check valve 110 and the first heat exchanger 102. In at least one embodiment, the system 100 can include one or more pressure relief valves 116 plumbed in parallel with the check valve 110, such as to release excess pressure between the check valve110 and the first heat exchanger 102 back towards the second heat exchanger 106 and / or the pump 108.

[0038] In at least one embodiment, a heat rejection method according to the disclosure can include passing a single-phase cooling fluid and a two-phase cooling fluid through one or more first heat exchangers 102 (thereby transferring heat from the single-phase cooling fluid to the two-phase cooling fluid), compressing the two-phase cooling fluid exiting the first heat exchanger 102, passing the two-phase cooling fluid through a second heat exchanger 106, thereby rejecting heat from the two-phase cooling fluid, pumping the two-phase cooling fluid through a check valve 110 and an expansion valve 112, closing the expansion valve 112 (thereby trapping a portion of the two-phase cooling fluid between the check valve and the expansion valve), or any combination thereof. In at least one embodiment, the compressing can be done using a compressor 104 and / or a pump 108. In at least one embodiment, the pumping can be done using a compressor 104 and / or a pump 108.

[0039] In at least one embodiment, the method can include stopping the pump 108 and / or the compressor 104 after closing the expansion valve 112. In at least one embodiment, the method can include stopping the pump 108 after closing the expansion valve 1 12 and / or stopping the compressor 104 after stopping the pump 108. In at least one embodiment, the method can include stopping the compressor 104 after closing the expansion valve 112 and / or stopping the pump 108 after stopping the compressor 104.

[0040] In at least one embodiment, the method can include stopping the pump 108 and / or the compressor 104 before closing the expansion valve 112. In at least one embodiment, the method can include stopping the pump 108 before closing the expansion valve 112 and / or stopping the compressor 104 after closing the expansion valve 112. In at least one embodiment, the method can includestopping the compressor 104 before closing the expansion valve 112 and / or stopping the pump 108 after closing the expansion valve 112. In at least one embodiment, the method can include stopping the pump 108, then stopping the compressor 104, and then closing the expansion valve 112. In at least one embodiment, the method can include stopping the compressor 104, then stopping the pump 108, and then closing the expansion valve 112.

[0041] In at least one embodiment, the method can include opening the expansion valve 112 before starting the compressor 104 and / or the pump 108. In at least one embodiment, the method can include opening the expansion valve 112, starting the compressor 104 after opening the expansion valve 112, and starting the pump 108 after starting the compressor 104. In at least one embodiment, the method can include opening the expansion valve 1 12, starting the pump 108 after opening the expansion valve 112, and starting the compressor 104 after starting the pump 108.

[0042] In at least one embodiment, the method can include opening the expansion valve 112 after starting the compressor 104 and / or the pump 108. In at least one embodiment, the method can include starting the compressor 104, starting the pump 108 after starting the compressor 104, and opening the expansion valve 112 after starting the pump 108. In at least one embodiment, the method can include starting the compressor 104, opening the expansion valve 112 after starting the compressor 104, and starting the pump 108 after opening the expansion valve 112. In at least one embodiment, the method can include starting the pump 108, starting the compressor 104 after starting the pump 108, and opening the expansion valve 112 after starting the compressor 104. In at least one embodiment, the method can include starting the pump 108, opening the expansion valve 112 after starting the pump 108, and starting the compressor 104 after opening the expansion valve 112.

[0043] In at least one embodiment, a split cooling system according to the disclosure can include a first heat exchanger configured to exchange heat from a single-phase cooling fluid to a two-phase cooling fluid, a compressor in fluid communication with the first heat exchanger and configured to compress the two- phase cooling fluid received in gaseous form from the first heat exchanger, a second heat exchanger in fluid communication with the compressor and configured to condense the two-phase cooling fluid received from the compressor, a pump in fluid communication between the first heat exchanger and the second heat exchanger, a check valve in fluid communication between the first heat exchanger and the pump, or any combination thereof. In at least one embodiment, the check valve can trap a portion of the two-phase cooling fluid between the check valve and the compressor, such as when the compressor is stopped. In at least one embodiment, the system can include an expansion valve, such as between the check valve and the first heat exchanger. In at least one embodiment, the check valve can trap a portion of the two-phase cooling fluid between the check valve and the expansion valve, such as when the expansion valve closes.

[0044] In at least one embodiment, the first heat exchanger and / or the compressor can be disposed within a building and exposed to an internal temperature within the building. In at least one embodiment, the second heat exchanger and / or the pump can be disposed outside the building and exposed to an external temperature outside the building. In at least one embodiment, the external temperature is expected to be well below the internal temperature and / or the freezing point of the single-phase cooling fluid, at least some of the time. In at least one embodiment, the check valve can be disposed within the building. In at least one embodiment, the check valve can contain, such as when the compressor is stopped, a portion of the two-phase cooling fluid within the building,such that the portion of the two-phase cooling fluid is exposed to the internal temperature within the building.

[0045] In at least one embodiment, the system can include a pressure relief valve plumbed between the check valve and the first heat exchanger. In at least one embodiment, the system can include a pressure relief valve plumbed in parallel with the check valve.

[0046] In at least one embodiment, a split cooling system according to the disclosure can include a first heat exchanger configured to exchange heat from a single-phase cooling fluid to a two-phase cooling fluid, a compressor in fluid communication with the first heat exchanger and configured to compress the two- phase cooling fluid received in gaseous form from the first heat exchanger, a second heat exchanger in fluid communication with the compressor and configured to condense the two-phase cooling fluid received from the compressor, a check valve in fluid communication with the first heat exchanger and / or the second heat exchanger, or any combination thereof. In at least one embodiment, the check valve can contain, such as when the compressor is stopped, a portion of the two-phase cooling fluid between the check valve and the compressor.

[0047] In at least one embodiment, the system can include an expansion valve. In at least one embodiment, the check valve can trap the portion of the two-phase cooling fluid between the check valve and the expansion valve, such as when the expansion valve closes. In at least one embodiment, the expansion valve and / or the check valve can be disposed within a building. In at least one embodiment, a portion of the two-phase cooling fluid can be exposed to an internal temperature within the building when trapped between the check valve and the expansion valve. In at least one embodiment, the compressor and the check valve can be disposed within a building. In at least one embodiment, aportion of the two-phase cooling fluid can be exposed to an internal temperature within the building when contained between the check valve and the compressor.

[0048] In at least one embodiment, the system can include a pressure relief valve plumbed between the check valve and the first heat exchanger. In at least one embodiment, the system can include a pressure relief valve plumbed in parallel with the check valve.

[0049] In at least one embodiment, a heat rejection method according to the disclosure can include passing a single-phase cooling fluid and a two-phase cooling fluid through a first heat exchanger, thereby transferring heat from the single-phase cooling fluid to the two-phase cooling fluid, compressing the two- phase cooling fluid exiting the first heat exchanger, passing the two-phase cooling fluid through a second heat exchanger, thereby rejecting heat from the two-phase cooling fluid, pumping the two-phase cooling fluid through a check valve and an expansion valve, closing the expansion valve, thereby trapping a portion of the two-phase cooling fluid between the check valve and the expansion valve, or any combination thereof. In at least one embodiment, the compressing can be done using a compressor and / or a pump. In at least one embodiment, the pumping can be done using a compressor and / or a pump.

[0050] In at least one embodiment, the method can include stopping the pump and the compressor after closing the expansion valve. In at least one embodiment, the method can include stopping the pump after closing the expansion valve and / or stopping the compressor after stopping the pump. In at least one embodiment, the method can include stopping the compressor after closing the expansion valve and / or stopping the pump after stopping the compressor.

[0051] In at least one embodiment, the method can include opening the expansion valve, starting the compressor after opening the expansion valve, and starting the pump after starting the compressor. In at least one embodiment, the method can include opening the expansion valve, starting the pump after opening the expansion valve, and starting the compressor after starting the pump.

[0052] Other and further embodiments utilizing one or more aspects of the disclosure can be devised without departing from the spirit of Applicant’s disclosure. For example, the devices, systems and methods can be implemented for numerous different types and sizes in numerous different industries. Further, the various methods and embodiments of the devices, systems and methods can be included in combination with each other to produce variations of the disclosed methods and embodiments. Discussion of singular elements can include plural elements and vice versa. The order of steps can occur in a variety of sequences unless otherwise specifically limited. The various steps described herein can be combined with other steps, interlineated with the stated steps, and / or split into multiple steps. Similarly, elements have been described functionally and can be embodied as separate components or can be combined into components having multiple functions.

[0053] The inventions have been described in the context of preferred and other embodiments and not every embodiment of the inventions has been described. Obvious modifications and alterations to the described embodiments are available to those of ordinary skill in the art having the benefits of the present disclosure. The disclosed and undisclosed embodiments are not intended to limit or restrict the scope or applicability of the inventions conceived of by the Applicant, but rather, in conformity with the patent laws, Applicant intends to fully protect all such modifications and improvements that come within the scope or range of equivalents of the following claims.

Claims

WHAT IS CLAIMED IS:1 . A system comprising: a first heat exchanger configured to exchange heat from a single-phase cooling fluid to a two-phase cooling fluid; a compressor in fluid communication with the first heat exchanger and configured to selectively compress the two-phase cooling fluid received in gaseous form from the first heat exchanger; a second heat exchanger in fluid communication with the compressor and configured to condense the two-phase cooling fluid received from the compressor; and a check valve in fluid communication with the first heat exchanger and the second heat exchanger, the check valve being configured to contain, when the compressor is stopped, a portion of the two-phase cooling fluid between the check valve and the compressor.

2. The system of claim 1 , further comprising an expansion valve and wherein the check valve is configured to trap the portion of the two-phase cooling fluid between the check valve and the expansion valve, when the expansion valve closes.

3. The system of claim 2, wherein the expansion valve and the check valve are disposed within a building and wherein the portion of the two-phase cooling fluid is exposed to an internal temperature within the building when trapped between the check valve and the expansion valve.

4. The system of claim 1 , wherein the compressor and the check valve are disposed within a building and wherein the portion of the two-phase cooling fluidis exposed to an internal temperature within the building when contained between the check valve and the compressor.

5. The system of claim 1 , further comprising a pressure relief valve plumbed between the check valve and the first heat exchanger, wherein the pressure relief valve is configured to selectively relieve pressure from a liquid return line of the first heat exchanger to the second heat exchanger.

6. The system of claim 1 , further comprising a pressure relief valve plumbed in parallel with the check valve, wherein the pressure relief valve is configured to selectively relieve pressure from downstream of the check valve to upstream of the check valve.

7. The system of claim 1 , further comprising a pump in fluid communication with the first heat exchanger and the second heat exchanger; wherein the pump is configured to selectively pump the two-phase cooling fluid from the second heat exchanger to the first heat exchanger; and wherein the check valve is disposed fluidically between the pump and the first heat exchanger.

8. The system of claim 7, wherein the first heat exchanger is disposed within a building and exposed to an internal temperature within the building; wherein the compressor is disposed within the building and exposed to the internal temperature within the building; and wherein the second heat exchanger is disposed outside the building and exposed to an external temperature outside the building.

9. The system of claim 8, wherein the check valve is configured to contain the contained portion of the two-phase cooling fluid in a portion of the systemdisposed within the building and exposed to the internal temperature within the building.

10. The system of claim 8, further comprising a pressure relief valve plumbed between the check valve and the first heat exchanger, wherein the pressure relief valve is configured to selectively relieve pressure from a liquid return line of the first heat exchanger to the second heat exchanger.11 . The system of claim 8, further comprising a pressure relief valve plumbed in parallel with the check valve, wherein the pressure relief valve is configured to selectively relieve pressure from downstream of the check valve to upstream of the check valve.

12. The system of claim 8, further comprising an expansion valve and wherein the check valve is configured to trap the contained portion of the two-phase cooling fluid between the check valve and the expansion valve, when the expansion valve closes.

13. A method comprising: passing a single-phase cooling fluid and a two-phase cooling fluid through a first heat exchanger, thereby transferring heat from the singlephase cooling fluid to the two-phase cooling fluid; compressing, using a compressor, the two-phase cooling fluid exiting the first heat exchanger; passing the two-phase cooling fluid through a second heat exchanger, thereby rejecting heat from the two-phase cooling fluid; pumping, using a pump, the two-phase cooling fluid through a check valve and an expansion valve; andclosing the expansion valve, thereby trapping a portion of the two-phase cooling fluid between the check valve and the expansion valve.

14. The method of claim 13, further comprising stopping the pump after closing the expansion valve.

15. The method of claim 14, further comprising stopping the compressor after stopping the pump.

16. The method of claim 13, further comprising stopping the compressor after closing the expansion valve.

17. The method of claim 16, further comprising stopping the pump after stopping the compressor.

18. The method of claim 13, further comprising stopping the pump and the compressor after closing the expansion valve.

19. The method of claim 13, further comprising: opening the expansion valve; starting the compressor after opening the expansion valve; and starting the pump after starting the compressor.

20. The method of claim 13, further comprising: opening the expansion valve; starting the pump after opening the expansion valve; and starting the compressor after starting the pump.

Images