COOLING SYSTEM WITH ENHANCED LOW AMBIENT APPLICATION FOR LOW BOILING REFRIGERANT

CROSS-REFERENCE TO RELATED APPLICATIONS

[0001]The present application claims the benefit under 35 U.S.C § 119(e) to U.S. Provisional Application No. 63/675,476, filed Jul. 25, 2024, which is herein incorporated by reference in the entirety.

TECHNICAL FIELD

[0002]The present disclosure generally relates to the field of cooling systems, and more particularly, to a cooling system with enhancing low ambient application for low boiling refrigerants.

BACKGROUND

[0003]Recent regulations have since been adopted to phase down production and consumption of hydrofluorocarbons (HFCs) which have a high global warming potential (GWP) and contribute to climate change. Many refrigerants used in cooling systems contain HFC and thus have a high GWP. Accordingly, new refrigerants have been adopted that comply with recent regulations. However, such new refrigerants pose problems for many existing cooling systems (e.g., difficulty in switching on the compressor, or the like).

[0004]As such, there is a need for a cooling system and method that cures one or more shortfalls of the existing approaches.

SUMMARY

[0005]A cooling system is disclosed, in accordance with one or more embodiments of the present disclosure. In embodiments, the cooling system includes an air conditioning (CRAC) unit. In embodiments, the cooling system includes a refrigerant pump coupled to the CRAC unit, where the refrigerant pump refrigerant is configured to provide a refrigerant liquid to the CRAC unit. In embodiments, the cooling system includes a condenser coupled to the CRAC unit, where the condenser is configured to cool the provided refrigerant liquid. In embodiments, the cooling system includes one or more controllers communicatively coupled to the CRAC unit, and the refrigerant pump. In embodiments, the one or more controllers include one or more processors including a set of program instructions configured to cause the one or more processors to: receive outdoor temperature data from a temperature sensor; receive a predetermined outdoor temperature threshold; determine whether the received outdoor temperature data exceeds the received predetermined outdoor temperature threshold by comparing the received outdoor temperature data to the received predetermined outdoor temperature threshold, where the outdoor temperature data exceeds the received determined outdoor temperature threshold when the received outdoor temperature data is at least one of less than or equal to the received predetermined outdoor temperature; upon determining the received outdoor temperature does not exceed the received predetermined outdoor temperature threshold, generate one or more control signals configured to cause a compressor of the CRAC unit to be idled; and generate one or more control signals configured to cause the refrigerant pump to be activated.

[0006]A method for activating a pump operation circuit of a cooling system is disclosed, in accordance with one or more embodiments of the present disclosure. In embodiments, the method includes receiving outdoor temperature data from one or more outdoor temperature sensors. In embodiments, the method includes receiving a predetermined outdoor temperature threshold. In embodiments, the method includes determining whether the received outdoor temperature data exceeds the received predetermined outdoor temperature threshold by comparing the received outdoor temperature data to the received predetermined outdoor temperature threshold, where the outdoor temperature data exceeds the received determined outdoor temperature threshold when the received outdoor temperature data is at least one of less than or equal to the received predetermined outdoor temperature. Upon determining the received outdoor temperature does not exceed the received predetermined outdoor temperature threshold, the method includes generating one or more control signals configured to cause a compressor of a computer room air conditioning (CRAC) unit to be idled. In embodiments, the method includes generating one or more control signals configured to cause a pump to be activated.

[0007]It is to be understood that both the foregoing general description and the following detailed description are exemplary and explanatory only and are not necessarily restrictive of the present disclosure. The accompanying drawings, which are incorporated in and constitute a part of the specification, illustrate subject matter of the disclosure. Together, the descriptions and the drawings serve to explain the principles of the disclosure.

BRIEF DESCRIPTION OF THE DRAWINGS

[0008]The numerous advantages of the disclosure may be better understood by those skilled in the art by reference to the accompanying figures.

[0009]FIG. 1 is a simplified block diagram view of a cooling system, in accordance with one or more embodiments of present disclosure.

[0010]FIG. 2 is a simplified schematic of a condenser of the cooling system, in accordance with one or more embodiments of the present disclosure.

[0011]FIG. 3A is a simplified schematic of a computer room air conditioner unit of the cooling system, in accordance with one or more embodiments of the present disclosure.

[0012]FIG. 3B is a simplified schematic of a computer room air conditioner unit of the cooling system, in accordance with one or more embodiments of the present disclosure.

[0013]FIG. 3C is a simplified schematic of a computer room air conditioner unit of the cooling system, in accordance with one or more embodiments of the present disclosure.

[0014]FIG. 3D is a simplified schematic of a computer room air conditioner unit of the cooling system, in accordance with one or more embodiments of the present disclosure.

[0015]FIG. 4 is a simplified schematic of a cooling system having a pump operation circuit, in accordance with one or more embodiments of the present disclosure.

[0016]FIG. 5 is a flow diagram depicting a method or process for activating the pump operation circuit, in accordance with one or more embodiments of the present disclosure.

DETAILED DESCRIPTION

[0017]Reference will now be made in detail to the subject matter disclosed, which is illustrated in the accompanying drawings.

[0018]Embodiments of the present disclosure are directed to a cooling system with enhanced low ambient application. The cooling system may allow operation when the outdoor temperature is very low (e.g., down to −30° C., and in some instances, down to-60° C.). For example, the refrigerant charge of the cooling system may be moved on the outside part of the circuit. For instance, the refrigerant pump may be initially switched on instead of the compressor, such that the refrigerant pump is able to move the refrigerant from the condenser to the evaporator. In other words, if the outdoor temperature is below a certain threshold, a pump operation circuit may be activated, such that the activation of the compressors is inhibited and the pump is modulated based on a received cooling request. Once the pump mode timer has elapsed (e.g., once a predetermined time has lapsed), the compressor's activation inhibition may be removed and the pump may be shut-off, such that normal system control is restored without further forcing.

[0019]It is contemplated herein that the cooling system may provide a number of advantages. For example, by using the pump, the evaporating temperature is increased, thereby reducing the risk of dehumidification and freezing at the coil. Further, the cooling system may reduce carbon footprint and have a low global warming potential (GWP), thereby reducing direct emissions. For example, the low-GWP of the refrigerant may meet the industry standards and/or regulations (e.g., European Union (EU) F-Gas Regulation 2024/573), where the low-GWP of the refrigerant used by the cooling system may be below 750. The cooling system may further reduce indirect emissions due to the improved efficiency of the cooling system itself.

[0020]FIG. 1 illustrates a simplified block diagram of a cooling system 100, in accordance with one or more embodiments of the present disclosure.

[0021]The cooling system 100 may include one or more computer room air conditioner (CRAC) units 102. For example, the one or more CRAC units 102 may be coupled to one or more condensers 104 (or heat rejection units) to provide cooled liquid to the one or more CRAC units 102. Further, the one or more condensers 104 may transfer heat from the return fluid from the one or more CRAC units 102 to a cooler medium, such as outside ambient air.

[0022]The cooling system 100 may include one or more refrigerant pumps 106 (or refrigerant units). The one or more refrigerant pumps 106 may provide refrigerant to the one or more CRAC units 102. In some instances, the one or more CRAC units 102 may be phase change refrigerant air conditioning systems having refrigerant compressors, such as a direct expansion (DX) system, as discussed further herein.

[0023]The one or more refrigerants may include any suitable low-GWP refrigerant including, but not limited to, R513A, R515B, R1234ze, R471A, and the like.

[0024]The cooling system 100 may further include one or more controllers 108 including one or more processors 110 and memory 112. The one or more controllers 108 may adjust one or more settings of the one or more components of the cooling system 100 based on one or more factors (e.g., outdoor temperature), as discussed further herein. For example, the one or more controllers 108 may be configured to control one or more circuits of the cooling system 100. For instance, as discussed further herein with respect to FIG. 4, the one or more controllers 108 may be configured to control a pump operation circuit and a cooling circuit.

[0025]The one or more controllers 108 may be configured to couple to various sensors, such as outdoor temperature sensors and pressure sensors disposed to sense pressure in the condenser coil (e.g., coil 304 shown in FIGS. 3A, 3B, 3C, and 3D).

[0026]FIG. 2 illustrates a simplified schematic of exemplary CRAC units 102, in accordance with one or more embodiments of the present disclosure. In particular, FIG. 2 illustrates three stacked CRAC units 200 (e.g., horizontally stacked), in accordance with one or more embodiments of the present disclosure. It is contemplated that the CRAC units 102 may include air or liquid cooled heat exchangers.

[0027]The CRAC unit 102 may include a cabinet 202 configured to house one or more components of the CRAC unit 102. For example, each CRAC unit 102 may include an evaporator 204 (or coil) disposed within the cabinet 202. In some instances, the evaporator 204 may include a “v-coil” assembly including one or more “v-shaped” coils. In other instances, the evaporator 204 may include a slab coil assembly including one or more slab coils. It is contemplated herein that the evaporator 204 may include any type of coil, therefore the above description and associated figures shall not be construed as limiting the scope of the present disclosure.

[0028]Each CRAC unit 102 may include a filter 206 disposed adjacent to (e.g., directly above or next to) the evaporator 204. In this regard, the evaporator 204 may be better utilized within the CRAC unit 102 to increase unit efficiency based on the filter device's close proximity to the evaporator 204. Filters are generally discussed in U.S. Patent Publication No. 2025/0108318, published Apr. 3, 2025, which is incorporated herein by reference in the entirety.

[0029]Each CRAC unit 102 may include one or more fans 208. For example, the one or more fans 208 may be disposed in one or more top portions of the cabinet 202. For instance, a first fan 208 may be disposed in a first top portion of a first cabinet 202, a second fan 208 may be disposed in a second top portion of a second cabinet 202, and a third fan 208 may be disposed in a third top portion of a third cabinet 202. The one or more fans 208 may be arranged proximate to the evaporator 204 and filter 206, such that air may be drawn in via an inlet 210 of the cabinet 202 and cooled by the evaporator 204. After being cooled, the cooled air may be directed out via a plenum (not shown).

[0030]Each CRAC unit 102 may further include a compressor 212. For example, the refrigerant may be circulated by the compressor 212 through the condenser 104 located outside. It is contemplated herein that the compressor 212 may be suitable type of compressor including, but not limited to, a scroll compressor, centrifugal compressor, rotatory compressor, or the like.

[0031]The compressor 212 may be coupled to one or more drivers 214. For example, the compressor 212 may be configured to one or more variable speed drivers (VSDs) configured to automatically adjust the compressor's operating speed to match production of compressed air to demand in real-time (or near real-time).

[0032]At least one CRAC unit 102 may further include a humidifier 216. The humidifier 216 may be configured to control a humidity level within the respective CRAC unit 102. For example, the humidifier 216 may be activated when the relative humidity in the space drops below a humidity setpoint (or threshold), where the humidifier 216 increases the amount of moisture in the space when activated.

[0033]At least one CRAC unit 102 may further include an electrical panel 218.

[0034]One or more of the CRAC units 102 may include an expansion value 220. For example, the expansion valve 220 may be configured to control a pressure level from the liquid refrigerant to allow expansion or change of state from a liquid to a vapor in the evaporator.

[0035]FIGS. 3A, 3B, 3C, and 3D illustrate simplified schematics of exemplary condensers 104 (or heat rejection units) coupled to the one or more refrigerant pumps 106, in accordance with one or more embodiments of the present disclosure. In particular, FIGS. 3A and 3B illustrate a single condenser assembly and FIGS. 3C and 3D illustrate stacked condenser assemblies (e.g., horizontally stacked), in accordance with one or more embodiments of the present disclosure. It is contemplated herein that the condenser 104 may be any suitable type of condenser conventionally used in cooling systems, such as an air-cooled condenser, a water-cooled condenser, or glycol cooled condenser.

[0036]The condenser assembly or assemblies (or simply condenser or condensers) may be installed outside. For example, the condensers 104 may be installed on a rooftop or mezzanine on a rooftop. In this regard, the condensers 104 may transfer heat from the return fluid from the one or more CRAC units 102 to a cooler medium, such as the outside ambient air.

[0037]Each condenser 104 may include a cabinet 302 configured to house one or more components of the condenser 104. For example, each condenser 104 may include one or more coils 304. In some instances, the condenser 104 may include a “v-coil” assembly (or “V-condenser block”) including one or more “v-shaped” coils 304. In other instances, the condenser 104 may include a slab coil assembly including one or more slab coils. It is contemplated herein that the condenser 104 may include any type of coil, therefore the above description and associated figures shall not be construed as limiting the scope of the present disclosure.

[0038]Each condenser 104 may include one or more fans 306. For example, the one or more fans 306 may be disposed on one or more surfaces of the cabinet 302. For instance, a first fan 306a may be disposed on a first top surface 302a of the cabinet 302 and a second fan 306b may be disposed on a second top surface 302b the cabinet 302. The one or more fans 208 may be arranged proximate to the coils 304, such that air may be drawn via the one or more fans 306.

[0039]The condenser 104 may be coupled to the refrigerant pump 106. For example, the refrigerant pump 106 may couple to a portion of the cabinet 302 of the condenser 104. Referring to FIGS. 3A and 3B, a single condenser may include a single refrigerant pump 106 coupled to a frame member of the cabinet 302. Referring to FIGS. 3C and 3D, two condensers stacked horizontally may include a single refrigerant pump 106 coupled to a frame member of at least one of a first cabinet 302 or a second cabinet 302, where the single refrigerant pump 106 provides refrigerant to both condensers.

[0040]It is contemplated herein that in conventional systems, the refrigerant pump was an external module to be installed between the indoor and outdoor units. Conversely, the refrigerant pump 106 of the present disclosure may be coupled to the condenser 104 such that the two components are merged on a single frame including both heat rejection and the refrigerant pump. For example, the refrigerant pump 106 may be arranged within the cooling system 100 such that it is placed immediately after a liquid receiver 308 for granting refrigerant at liquid phase at the inlet to avoid cavitation risk.

[0041]The phase change refrigerant may be circulated by the compressor 212 through the condenser 104, the expansion valve 220 of the CRAC unit 102, the evaporator 204, and back to compressor 212 of the CRAC unit 102.

[0042]The condenser 104 may include an electrical panel 310.

[0043]FIG. 4 illustrates the cooling system 100 including a pump operation circuit 400 and a direct expansion (DX) circuit 402, in accordance with one or more embodiments of the present disclosure.

[0044]The controller 108 of the cooling system 100 may be configured to manage one or more economization phases based on one or more parameters including outdoor temperatures. For example, the controller 108 may activate one of the pump operation circuit 400 (e.g., liquid pressurization cycle) or the direct expansion (DX) circuit 402 (e.g., vapor compression cycle) based on the outdoor temperature.

[0045]As discussed further herein, when the outdoor temperature is less than (or equal to) a predetermined threshold, as measured by an outdoor temperature sensor 404, the pump circuit 400 may be activated. When the outdoor temperature exceeds (e.g., is greater than) the predetermined threshold, as measured by the outdoor temperature sensor 404, the DX circuit 402 may be activated.

[0046]The pump operation circuit 400 may include one or more pump operation components including, but is not limited to, the refrigerant pump 106, a solenoid valve 403, and one or more sensors (e.g., temperature sensors 404 and pressor sensors 405).

[0047]When the pump operation circuit 400 is activated, the solenoid valve 403 may be activated. For example, the solenoid valve 403 may be controlled by the controller 108 of the cooling system 100 and used to control the refrigerant from the refrigerant pump 106. When the pump operation circuit 400 is activated, all of the cooling system's compressors 212 are idled and bypassed. For example, the pump operation circuit 400 may be activated using a method 500, as discussed further herein with respect to FIG. 5.

[0048]When the direct expansion circuit 402 is activated, the pumps 106 are idled and bypassed, such that the compressors 212 drive heat rejection. It is contemplated herein that during standard operation the cooling system 100 starts with the direct expansion circuit 402 and later according to the operating conditions checks whether the cooling system 100 needs to active the pump operation circuit 400.

[0049]FIG. 5 illustrates a conceptual view of a flow diagram depicting a method 500 for activating the pump operation circuit 400 of the cooling system 100, in accordance with one or more embodiments of the present disclosure.

[0050]In step 502, the method 500 may include determining whether the pump operation circuit needs to be activated. For example, the one or more controllers 108 may be configured to compare an outdoor temperature data measured via the one or more outdoor temperature sensors 404 and a predetermined threshold. In this regard, if the outdoor temperature measured by the outdoor temperature sensors 404 is greater than the predetermined threshold, the one or more controllers 108 may determine that the outdoor temperature exceeds the predetermined threshold. Further, if the outdoor temperature measured by the outdoor temperature sensors 404 is less than (or equal to) the predetermined threshold, the one or more controllers 108 may determine that the outdoor temperature does not exceed the predetermined threshold.

[0051]The predetermined threshold may include a temperature threshold. For example, the predetermined temperature threshold may be between −5° C. and +5° C. For instance, the predetermined temperature threshold may be 0° C. In this regard, if the measured outdoor temperature is less than (or equal to) the predetermined threshold temperature, the method may proceed to step 504. Further, if the measured outdoor temperature is greater than the predetermined threshold temperature, the method may proceed to step 518, as discussed further herein.

[0052]It is contemplated herein that the temperature thresholds provided above are merely for illustrative purposes, the threshold may be adjusted to improve the efficiency of the cooling system 100. For example, the temperature threshold may be driven by the refrigerant and/or environment.

[0053]In step 504, upon determining the outdoor temperature data does not exceed the predetermined threshold (e.g., is less than or equal to the predetermined threshold) (in step 502), the method 500 may include starting the pump mode timer. For example, the one or more controllers 108 may be configured to direct a timer of the pump (or a remote timer coupled to the pump) to start. In this regard, the one or more controllers 108 may be configured to disenable the possibility to switch the compressor until a specific condition is reached.

[0054]In step 506, the method 500 may include inhibiting compressors activation. For example, the one or more controllers 108 may be configured to generate one or more control signals configured to cause the compressor 212 of the CRAC unit 102 to be idled (or bypassed), as shown in FIG. 4.

[0055]In step 508, the method 500 may include turning the pump on. For example, the one or more controllers 108 may be configured to generate one or more control signals configured to cause the refrigerant pump 106 to be turned on (or activated).

[0056]In step 510, the method 500 may include modulating the pump based on one or more received cooling requests. For example, the user may provide one or more cooling requests to the cooling system 100. For instance, the one or more cooling requests may be provided to the cooling system 100 via one or more user input devices communicatively coupled to the cooling system 100 (e.g., to the controller 108 of the cooling system 100).

[0057]The one or more cooling requests may correspond to a requested cooling capacity, where the requested cooling capacity is associated with a regulated pump speed, or the like.

[0058]In step 512, the method 500 may include determining whether the pump mode timer has elapsed. For example, the one or more controllers 108 may receive a predetermined amount of pump time in the cooling request (received in step 510) and compare the elapsed time recorded by the pump timer of the refrigerant pump 106 (or a remote timer coupled to the refrigerant pump 106).

[0059]In a step 514, upon determining the pump mode timer has not elapsed, the method 500 may include modulating the pump based on one or more received cooling requests (step 510).

[0060]In step 516, upon determining the pump mode timer has elapsed, the method 500 may include removing the compressors activation inhibition. For example, the one or more controllers 108 may be configured to generate one or more control signals configured to cause the compressor 212 of the CRAC unit 102 to be activated.

[0061]In step 518, the method 500 may include turning off the pump. For example, the one or more controllers 108 may be configured to generate one or more control signals configured to cause the refrigerant pump 106 to be idled (or bypassed).

[0062]In step 520, the method 500 may include activating the direct expansion circuit 402. For example, the one or more controllers 108 may resume normal operation associated with the direct expansion circuit 402.

[0063]Upon determining the outdoor temperature data does exceed the predetermined threshold (in step 502), the method 500 may proceed to the step 520. For example, the one or more controllers 108 may continue normal operation associated with the direct expansion circuit 402.

[0064]It is noted the method 500 is not limited to the steps and/or sub-steps provided. The method 500 may include more or fewer steps and/or sub-steps. In addition, the method 500 may perform the steps and/or sub-steps simultaneously. Further, the method 500 may perform the steps and/or sub-steps sequentially, including in the order provided or an order other than provided. Therefore, the above description should not be interpreted as a limitation on the scope of the disclosure but merely an illustration.

[0065]Referring back to FIG. 1, it is noted herein that the one or more components of system 100 may be communicatively coupled to the various other components of system 100 in any manner known in the art. For example, the one or more processors may be communicatively coupled to each other and other components via a wireline (e.g., copper wire, fiber optic cable, and the like) or wireless connection (e.g., RF coupling, IR coupling, WiMax, Bluetooth, 3G, 4G, 4G LTE, 5G, and the like). By way of another example, the controller 108 may be communicatively coupled to one or more components of system 100 via any wireline or wireless connection known in the art.

[0066]The one or more processors may include any one or more processing elements known in the art. In this sense, the one or more processors may include any microprocessor device configured to execute algorithms and/or program instructions. In general, the term “processor” may be broadly defined to encompass any device having one or more processing elements, which execute a set of program instructions from a non-transitory memory medium (e.g., the memory), where the one or more sets of program instructions are configured to cause the one or more processors to carry out any of one or more process steps.

[0067]The memory may include any storage medium known in the art suitable for storing the one or more sets of program instructions executable by the associated one or more processors. For example, the memory may include a non-transitory memory medium. For instance, the memory may include, but is not limited to, a read-only memory (ROM), a random access memory (RAM), a magnetic or optical memory device (e.g., disk), a magnetic tape, a solid state drive, and the like. The memory may be configured to provide display information to the user device. In addition, the memory may be configured to store user input information from one or more user input devices. The memory may be housed in a common controller housing with the one or more processors. The memory may, alternatively or in addition, be located remotely with respect to the spatial location of the processors and/or the one or more controllers. For instance, the one or more processors, the one or more controllers may access a remote database, accessible through a network (e.g., internet, intranet, and the like) via one or more communication interfaces.

[0068]It is noted that the one or more controllers may be housed in a common housing or housed external. As such, FIG. 1 is provided merely for illustrative purposes and shall not be construed as limiting the scope of the present disclosure.

[0069]In a general sense, those skilled in the art will recognize that the various aspects described herein which can be implemented, individually and/or collectively, by a wide range of hardware, software, firmware, or any combination thereof can be viewed as being composed of various types of “electrical circuitry.” Consequently, as used herein “electrical circuitry” includes, but is not limited to, electrical circuitry having at least one discrete electrical circuit, electrical circuitry having at least one integrated circuit, electrical circuitry having at least one application specific integrated circuit, electrical circuitry forming a general purpose computing device configured by a computer program (e.g., a general purpose computer configured by a computer program which at least partially carries out processes and/or devices described herein, or a microprocessor configured by a computer program which at least partially carries out processes and/or devices described herein), electrical circuitry forming a memory device (e.g., forms of random access memory), and/or electrical circuitry forming a communications device (e.g., a modem, communications switch, or optical-electrical equipment). Those having skill in the art will recognize that the subject matter described herein may be implemented in an analog or digital fashion or some combination thereof.

[0070]The herein described subject matter sometimes illustrates different components contained within, or connected with, different other components. It is to be understood that such depicted architectures are merely exemplary, and that in fact many other architectures can be implemented which achieve the same functionality. In a conceptual sense, any arrangement of components to achieve the same functionality is effectively “associated” such that the desired functionality is achieved. Hence, any two components herein combined to achieve a particular functionality can be seen as “associated with” each other such that the desired functionality is achieved, irrespective of architectures or intermedial components. Likewise, any two components so associated can also be viewed as being “operably connected”, or “operably coupled”, to each other to achieve the desired functionality, and any “two components capable of being so associated can also be viewed as being “operably couplable”, to each other to achieve the desired functionality. Specific examples of operably couplable include but are not limited to physically mateable and/or physically interacting components and/or wirelessly interactable and/or wirelessly interacting components and/or logically interacting and/or logically interactable components.

[0071]While particular aspects of the present subject matter described herein have been shown and described, it will be apparent to those skilled in the art that, based upon 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 to encompass within their scope all such changes and modifications as are within the true spirit and scope of the subject matter described herein. Furthermore, it is to be understood that the invention is defined by the appended claims.