CN110160281A - Pump refrigerant cooling system and built-in redundancy with l+1 to N+1 - Google Patents

Abstract

The present invention discloses a pumped refrigerant cooling system with l+1 to N+1 and built-in redundancy. A pumped refrigerant cooling system has a cooling unit associated with a pump unit for providing working fluid to the cooling unit to enable cooling of a space. The pumped refrigerant cooling system also includes a redundant pump unit that is activated when the primary pump unit associated with the cooling unit becomes inoperative. The primary pump unit is deactivated in favor of the redundant pump unit. Once the primary pump unit is in a state suitable for restarting, the redundant pump unit is deactivated and the primary pump unit is restarted.

Description

Pumped refrigerant cooling system with l+1 to N+1 and built-in redundancy

This application is a divisional application of an invention application with the application number 2012105991938 and titled "Pumped refrigerant cooling system with l+1 to N+1 and built-in redundancy" filed on December 27, 2012.

Cross References to Related Applications

This application claims the benefit of priority to US Provisional Application No. 61/580,695, filed December 28, 2011. The entire disclosure of the above application is incorporated by reference.

technical field

The present disclosure relates to pumped refrigerant cooling systems for precision cooling applications with primary cooling circuit redundancy.

Background technique

This section provides background information related to the present disclosure which is not necessarily prior art.

A data center is a room that contains many electronic devices, such as computer servers. Data centers and the equipment contained therein typically have optimal environmental operating conditions, particularly temperature and humidity. Climate control systems maintain the proper temperature and humidity in the data center.

The climate control system includes a cooling system that cools the air and provides cool air to the data center. The cooling system may include air conditioning units, such as computer room air handling (CRAH) or computer room air conditioning (CRAC) units, that cool the air provided to the data center. A data center may have a raised floor and cool air is brought in through vents in the raised floor. The raised floor can be constructed to provide plenums between the cold air outlets of the CRAH (or CRAHs) or CRAC (or CRACs) and vents in the raised floor, or alternatively, using ducts such as ) of the separate air chamber (plenum).

Data centers can also have hard floors. CRACS may for example be placed in rows of electronic equipment, their cooling air supplies may be arranged towards respective cold aisles, or CRACS may be arranged along the walls of a data center. Equipment racks at a data center may be arranged in a hot aisle/cold aisle configuration with the equipment racks arranged in rows. Typically the cold air inlet of a row of racks at the front of the rack faces the cool air inlet of a row of racks passing through the cold aisle, and the hot air outlet of a row of racks faces the hot air outlet of a row of racks passing through the hot aisle .

One type of cooling system uses a pumped refrigerant cooling unit, such as that used in the XD system available from the Liebert Company of Columbus, Ohio. The Liebert XD system has two cooling circuits, which may also be referred to as cooling circuits or cycles. The primary circuit uses chilled water or a refrigerant such as R407C, and the secondary circuit uses a pumped refrigerant such as R134a. The primary circuit includes a fluid to fluid heat exchanger for cooling the pumped refrigerant circulating in the secondary circuit. The secondary loop includes one or more phase change cooling modules with a fluid to air heat exchanger through which a refrigerant is circulated to cool the air flowing through the heat exchanger. Depending on the particular design, a heat exchanger may typically include an evaporator coil and a flow regulator or expansion valve.

The basic diagram for the two cooling loops (or cycles) of the Liebert XD system is shown and described in USSN 10/904,889, entitled "Cooling System for High Density Heat Load," the entire disclosure of which is incorporated Here for reference. Figures 1 and 2 of the aforementioned application are included herein as Figures 1 and 2 for description.

Referring to FIGS. 1 and 2 , the disclosed cooling system 10 includes a first cooling circuit 12 (primary cooling circuit) in thermal communication with a second circuit 14 (secondary cooling circuit). The disclosed cooling system 10 also includes a control system 90 . The first and second cycles 12 and 14 each include an independent working fluid. The working fluid in the second cycle is any volatile fluid suitable as a conventional refrigerant, including but not limited to chlorofluorocarbons (CFCs), hydrofluorocarbons (HFCs), or hydrochlorofluorocarbons (HCFCs). The use of a volatile working fluid eliminates the use of water over sensitive equipment, as is sometimes done in conventional systems for cooling computer rooms. The second cycle 14 includes a pump 20 , one or more first heat exchangers (evaporators) 30 , a second heat exchanger 40 , and tubes interconnecting the different components of the second cycle 14 . The second cycle 14 is not a vapor compression refrigeration system. Instead, the second cycle 14 uses a pump 20 instead of a compressor to circulate the volatile working fluid for heat dissipation from the heat load. The pump 20 is preferably capable of pumping the volatile working fluid throughout the second cooling cycle 14 and is preferably controlled by a control system implemented by the controller 90 .

The first heat exchanger 30 is a gas-liquid heat exchanger, and when the second working fluid passes through the second fluid path in the first heat exchanger 30, the gas-liquid heat exchanger flows from a heat load (not shown) to a second 2. The working fluid dissipates heat. For example, the gas-liquid heat exchanger 30 may include a plurality of tubes for the working fluid arranged to allow hot air to pass therebetween. It is understood that any number of gas-to-liquid heat exchangers known in the art can be used in the disclosed cooling system 10 . A flow regulator 32 may be connected between the piping 22 and the inlet of the evaporator 30 to regulate the flow of working fluid into the evaporator 30 . Flow regulator 32 may be any type of device for regulating flow in cooling system 10 . Flow regulator 32 preferably maintains a constant output flow independent of inlet pressure above the system operating pressure range. In the embodiment of FIGS. 1 and 2 , the second cycle 14 includes a plurality of evaporators 30 and a flow regulator 32 connected to the pipe 22 . However, the disclosed system may have one or more than one evaporator 30 and flow regulator 32 connected to tube 22 .

The second heat exchanger 40 is a liquid-to-liquid heat exchanger that transfers heat from the second working fluid to the first cycle 12 . It will be appreciated that any number of liquid-to-liquid heat exchangers known in the art may be used with the disclosed cooling system 10 . For example, liquid-to-liquid heat exchanger 40 may include a plurality of hoses for one fluid disposed in a chamber or shell containing a second fluid. Coaxial ("pipe-in-pipe") exchangers may also be suitable. In certain embodiments, it is preferred to use a plate heat exchanger. The second cycle 14 may also include a receiver 50 connected to the outlet pipe 46 of the second heat exchanger 40 by a bypass line 52 . The receiver 50 may store and collect working fluid in the second cycle 14 to allow for changes in temperature and thermal load.

In one embodiment, a gas-to-liquid heat exchanger 30 may be used to cool a room containing computer equipment. For example, the fan 34 may draw air from the room (heat load) through the heat exchanger 30 where the second working fluid absorbs heat from the air. In another embodiment, the air-to-liquid heat exchanger 30 may be used to remove heat directly from heat-generating electronic equipment (heat loads) by installing the heat exchanger 30 at or near the equipment. For example, the electronics are typically contained within a housing (not shown). A heat exchanger 30 may be mounted to the housing, and a fan 34 may draw air from the housing through the heat exchanger 30 . Alternatively, the first exchanger 30 may be in direct thermal contact with a heat source, such as a cold plate. Those skilled in the art will appreciate that the heat transfer rates, dimensions, and other design parameters of the disclosed cooling system 10 components depend on the disclosed cooling system 10 dimensions, the magnitude of the thermal load being managed, and other details of the particular implementation.

In the embodiment of the disclosed cooling system 10 depicted in FIG. 1 , the first circuit 12 includes a chilled water circuit 60 connected to the liquid-to-liquid heat exchanger 40 of the second circuit 14 . In particular, the second heat exchanger 40 has first and second portions or fluid paths 42 and 44 in thermal communication with each other. A second path 42 for a volatile working fluid is connected between the first heat exchanger 30 and the pump 20 . The first fluid path 44 is connected to a chilled water circulation 60 . Chilled water cycle 60 may be similar to those known in the art. Chilled water system 60 includes a first working fluid that absorbs heat from a second working fluid through liquid-to-liquid heat exchanger 40 . The first working fluid is then cooled by techniques known in the art for conventional chilled water cycles. In general, the first working fluid can be volatile or non-volatile. For example, in the embodiment of FIG. 1, the first working fluid may be water, ethylene glycol, or a mixture thereof. Thus, the embodiment of the second cycle 14 in Figure 1 can be constructed as a self-contained unit housing the pump 20, the gas-to-liquid heat exchanger 30 and the liquid-to-liquid heat exchanger 40, and can be connected to an existing chilled water service such as Available in buildings to accommodate cooled equipment.

In the embodiment of the cooling system 10 disclosed in Figure 2, the second circuit 14 is substantially the same as described above. The first cycle 12 however includes a flow path 44 or first portion of a vapor compression refrigeration system 70 connected to the heat exchanger 40 of the second cycle 14 . As in the embodiment of FIG. 1 , instead of using chilled water to remove heat from the second cycle 14 , the refrigeration system 70 in FIG. 2 is directly connected to the liquid-to-liquid heat exchanger 40 or the "other half" thereof. Vapor-compression refrigeration system 70 may be substantially similar to those known in the art. A typical vapor compression refrigeration system 70 includes a compressor 74 , a condenser 76 and an expansion device 78 . Tubes 72 interconnect these components and to the first flow path 44 of the heat exchanger 40 .

Vapor compression refrigeration system 70 removes heat from a second working fluid passing through second heat exchanger 40 by absorbing heat from exchanger 40 with the first working fluid and radiating heat to the environment (not shown). The first working fluid may be volatile. For example, in the embodiment of FIG. 2, the first working fluid may be any conventional chemical refrigerant including, but not limited to, chlorofluorocarbons (CFCs), hydrofluorocarbons (HFCs), or hydrochlorofluorocarbons (HCFCs). Expansion device 78 may be a valve, orifice, or other device known to those skilled in the art to create a pressure drop across the working fluid. Compressor 74 may be any type of compressor known in the art so as to be suitable for refrigerant service, such as reciprocating compressors, scroll compressors, and the like. In the embodiment depicted in Figure 2, the cooling system 10 is integral. For example, vapor compression refrigeration system 70 may be part of a single unit that also houses pump 20 and liquid-to-liquid heat exchanger 30 .

During operation of the disclosed system, pump 20 moves working fluid through tube 22 to gas-liquid heat exchanger 30 . The pump increases the pressure of the working fluid while its enthalpy remains substantially the same. The pumped working fluid can thus enter the gas-liquid heat exchanger or evaporator 30 of the second cycle 14 . A fan 34 may draw air from the heat load through the heat exchanger 30 . When hot air enters the air-to-liquid heat exchanger 30 from a heat load (not shown), the volatile working fluid absorbs heat. As the fluid warms up through the heat exchanger, some of the volatile working fluid will evaporate. In a fully loaded cooling system 10, the fluid exiting the first heat exchanger 30 may be substantially saturated steam. Vapor flows from heat exchanger 30 to liquid-liquid heat exchanger 40 through tube 36 . In the tube or return line 36, the working fluid is substantially in a vapor state, and while its enthalpy remains substantially constant, the pressure of the fluid drops. In the liquid-to-liquid heat exchanger 40 , vapor in the second fluid path 42 is condensed by transferring heat to the first, cooler fluid of the first cycle 12 in the first fluid path 44 . Condensed working fluid exits heat exchanger 40 through tube 46 and enters pump 20 where second cycle 14 may repeat.

The first cooling cycle 12 operates in conjunction with the second cycle 14 to remove heat from the second cycle 14 by absorbing heat from the second working fluid into the first working fluid and rejecting the heat to the environment (not shown). As noted above, the first cycle 12 may include a chilled water system 60 as shown in FIG. 1 or a vapor compression refrigeration system 70 as shown in FIG. 2 . During operation of chilled water system 60 of FIG. 1 , for example, a first working fluid may flow through first fluid path 44 of heat exchanger 40 and may be cooled in a cooling tower (not shown). During operation of the refrigeration system 70 of FIG. 2 , for example, a first working fluid passes through the first portion 44 of the liquid-to-liquid heat exchanger 40 and absorbs heat from the volatile fluid in the second cycle 14 . The working fluid evaporates during the process. The vapor is delivered to compressor 74 where the working fluid is compressed. Compressor 74 may be a reciprocating, scroll, or other type of compressor known in the art. After being compressed, the working fluid is sent through a discharge line to condenser 76 where heat is dissipated from the working fluid to an external heat sink, eg, the outdoor environment. Upon exiting condenser 76 , the refrigerant flows through the liquid line to expansion device 78 . As the refrigerant passes through the expansion device 78, the first working fluid experiences a pressure drop. Upon exiting the expansion device 78 , the working fluid flows through the first fluid path of the liquid-to-liquid heat exchanger 40 , which acts as an evaporator for the refrigeration cycle 70 .

Data center providers are constantly looking to improve reliability and up time from climate control systems. Accordingly, there is a continuing need for data center providers to improve redundancy in climate control systems in order to prevent unnecessary downtime of cooling electronics due to unexpected disruptions to the operation of the climate control system. One mode of redundancy consists in duplicating each element of the cooling system, such as the first cooling circuit 12 and the second cooling circuit 14 . This overall redundancy can be costly and very complex to design, implement and control of the cooling system. In a different configuration, redundancy may include the implementation of a cooling circuit, including for example a second reduced implementation of the second cooling circuit 14 shown in FIGS. 1 and 2 . The reduced redundancy may include the second pump unit 20 and half of the heat exchangers provided in the primary cooling system. Implementing these redundant systems will also require associated detection and control. Accordingly, the approximate cost of such a system can be in the range of 50% of the total base cooling load cost.

Another approach to redundancy in order to minimize equipment may include over-provisioning environments by utilizing cooling modules in complex, interleaved configurations. A fault in one cooling circuit can thus cross over to the region of a damaged cooling circuit via other cooling circuits. This overprovisioning again presents increased costs to the customer, including additional pumps, cooling modules, probing, piping and control systems over and above the conventional configuration shown in FIGS. 1 and 2 .

Contents of the invention

This section provides a summary of the disclosure, and is not exhaustive of its full scope or all of its features.

A cooling system for cooling a load having a primary cooling module that circulates refrigerant to the load. If the primary cooling module is disabled, the redundant cooling module provides flow of refrigerant to the load while the primary cooling module is disabled. The primary cooling module can be restarted in favor of the secondary cooling module. When this occurs, the secondary cooling module is deactivated. Redundant cooling modules are provided to provide fluid flow to any load in the cooling system.

Each of the primary cooling and secondary cooling modules also includes a pump for circulating the refrigerant, the pump providing the refrigerant at the first temperature to the load. Each of the primary and secondary modules also includes a condenser for receiving refrigerant from a load. Refrigerant received by the condenser is at a temperature higher than the first temperature. Each of the primary and secondary modules also includes a liquid receiver that receives refrigerant in a liquid state from the condenser.

A cooling system for cooling a load has a cooling module that circulates a refrigerant to the load. The primary cooling module has a pair of circuits including a controller, a pump and at least one valve. A pair of loops share a common condenser and receiver. A pair of circuits operate redundantly so that if one circuit is not in operation, the other circuit is operated to control fluid flow through the cooling module.

A cooling system includes a primary cooling module that provides refrigerant to a load. The cooling system also includes a first liquid receiver associated with the primary cooling module for receiving the refrigerant in a liquid state. In the event that insufficient primary cooling is detected, the secondary cooling module provides a supplemental flow of refrigerant across the load.

A cooling system includes a plurality of primary cooling modules. The primary cooling module provides refrigerant across a corresponding one of the plurality of heat loads. A plurality of liquid receivers associated with respective primary cooling modules receive refrigerant in a liquid state. The secondary cooling module selectively provides a supplemental flow of refrigerant across a load associated with the primary cooling module for which a failure has been detected. Each primary cooling module also includes a plurality of first pumps for providing refrigerant. A plurality of first pumps provides refrigerant at a first temperature to respective loads associated with respective primary cooling modules. A plurality of second condensers receive refrigerant from respective loads associated with respective primary cooling modules. The refrigerant received by the respective condenser is at a temperature higher than the first temperature.

A method for providing redundant cooling in a cooling system, the method includes providing a primary cooling module having a circuit, the primary cooling module providing cooling fluid to a heat load. The method also includes providing a secondary cooling module and commencing operation of the secondary cooling module. The method also includes inserting a secondary cooling module into the circuit, the secondary cooling module providing cooling fluid to the heat load. controlling a primary receiver valve between a primary receiver associated with the primary cooling module and a secondary receiver associated with the secondary cooling module to balance the flow between the primary receiver and the secondary cooling module prior to insertion of the secondary cooling module into the circuit pressure between the secondary receivers. The method also includes deactivating the primary cooling module.

A method for providing redundant control of a cooling system includes providing a plurality of primary cooling modules that provide refrigerant across respective heat loads. The method also includes providing a plurality of liquid receivers corresponding to respective primary cooling modules, each liquid receiver receiving refrigerant in a liquid state from a respective condenser associated with a respective primary cooling module. The secondary cooling modules selectively provide a supplemental flow of refrigerant across loads associated with selected primary cooling modules.

An apparatus includes a cooling module that provides refrigerant across a load. A first controller is associated with a first portion of a loop associated with a cooling module. A second controller is associated with a second portion of the loop associated with the cooling module. In the first mode, the first controller controls the first portion of the loop and the second controller controls the second portion of the loop. In the second mode, one of the first controller or the second controller controls both the first and second parts or the other of the first part of the circuit or the second part of the circuit.

Other areas of application will also become apparent from the description provided herein. The description and specific examples in this Summary section are intended for purposes of illustration only and do not limit the scope of the present disclosure.

Description of drawings

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

Figure 1 is a schematic diagram of the primary cooling circuit connected to the chilled water cycle;

Figure 2 is a schematic diagram of a cooling system with a primary cooling circuit utilizing a vapor compression refrigeration system;

Figure 3 is a schematic diagram of a cooling system arranged according to a first configuration;

Figure 4 is a schematic diagram of the cooling system of Figure 3 with the redundant pump unit initially in operation;

5 is a schematic diagram of the cooling system of FIG. 3 showing redundant pump units and loads following failure of the primary pump unit;

FIG. 6 is a schematic diagram of the cooling system of FIG. 3 with the deactivated main pump unit initially used for recovery;

Figure 7 is a schematic diagram of a previously deactivated main pump unit returning to operation;

FIG. 8 is a flowchart depicting FIG. 3 describing the process for activating the redundant pump unit and deactivating the primary pump unit;

FIG. 9 is a flow chart describing a process for activating a primary pump unit and deactivating a redundant pump unit;

Figure 10 is a schematic diagram of a pump unit with redundant control for chilled water flow control;

FIG. 11 is a flowchart describing a process for performing redundant chilled water flow control; and

12 is a flowchart describing a second process for performing redundant chilled water flow control.

Like reference numerals refer to like parts throughout the several views of the drawings.

Detailed ways

Exemplary embodiments are now described more fully with reference to the accompanying drawings.

Example embodiments are provided so that this disclosure will be thorough, and will fully convey the scope to those who are skilled in the art. Numerous specific details are set forth, such as examples of specific components, devices and methods, in order to provide a thorough understanding of embodiments of the present disclosure. It will be apparent to those skilled in the art that specific details need not be employed, that the illustrated embodiments may be embodied in many different forms and that neither should be construed to limit the scope of the disclosure. In some exemplary embodiments, well-known processes, well-known device structures, and well-known technologies are not described in detail.

The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting. When used herein, the singular forms "a," "an," and "the" may also be used to include the plural unless the context clearly dictates otherwise. The terms "comprising", "comprising", "comprising" and "having" are the same, and thus describe the presence of features, integers, steps, operations, elements and/or parts, but do not prevent the existence or addition of one or more other features, wholes, steps, operations, elements, parts, and/or combinations thereof. The method steps, processes, and operations described herein are not to be construed as necessarily being discussed or illustrated in a particular order, unless specifically identified as the order of presentation. It is also understood that additional or alternative steps may be employed.

When an element or layer is referred to as being "on," "bonded to," "connected to," or "coupled to" another element or layer, it may be directly on, bonded, connected, or bonded to another element or layer element or layer, or intervening elements or layers may occur. In contrast, when an element is referred to as being "directly on," "directly engaged to," "directly connected to," or "directly coupled to" another element or layer, there may be no intervening element or layer . Other words used to describe the relationship between elements should be interpreted in a similar fashion (e.g., "between" versus "directly between," "adjacent" versus "directly adjacent " corresponds to etc.). As used herein, the term "and/or" includes any and all combinations of one or more of the associated listed items.

Although the terms first, second, third, etc. may be used herein to describe various elements, components, regions, layers and/or sections, these elements, components, regions, layers and/or sections should not be referred to by such Term qualification. Such terms may be only used to distinguish one element, component, region, layer or section from another element, component, region, layer or section. Terms such as "first," "second," and other numerical terms when used do not imply a sequence or order unless clearly indicated by the context. Thus, a first element, component, region, layer or section discussed below could be termed a second element, component, region, layer or section without departing from the teachings of example embodiments.

Spatial terms such as "inside", "outside", "below", "below", "lower", "above", "upper" and the like may be used herein for convenience of description, so as to describe the relationship of one element or feature to another element or feature when shown in the figures. Spatially relative terms may be used to encompass different orientations in use or operation in addition to the orientation depicted in the figures. For example, if the device in the figures is turned over, elements described as "below" or "beneath" other elements or features would then be oriented "above" the other elements or features. Thus, an embodiment term "below" can encompass both an orientation of above and below. The device may be otherwise oriented (rotated 90 degrees or at other orientations) and each interpreted using the spatially relative descriptions herein.

FIG. 3 depicts a schematic diagram of a pumped refrigerant cooling system 100 with redundant pump units. The pumped refrigerant cooling system 100 includes a plurality of cooling subsystems 110a, 110b, ..., 110n, each having a respective primary pump unit 120a, 120b, ..., 120n. Each primary pump unit 120a, 120b, . . . , 120n provides pumping of working fluid to a heat exchanger or cooling device 122a, 122b, . . . , 122n. Each cooling unit 122a, 122b, . . . , 122n is in a cooled environment, such as a data room. It should be noted that n can be any positive integer and represents the number of similarly arranged element selections in the figure. For example, pump units 120a, 120b, . . . , 120n relate to n pump units. Those skilled in the art recognize that the number of pump units may vary, depending on the particular implementation of the pumped refrigerant cooling system 100 described herein. This numerical convention can describe other similar units. In some cases, n (or other numbers) of elements may be commonly described using reference numerals instead of a, b, . . . , n. Additionally, the same reference numerals may be used throughout the specification to describe similar elements.

Each main pump unit 120 includes a first pump 124 and a second pump 126 that pump working fluid at high pressure to respective check valves 132 , 134 . The pumps 124, 126 may be provided in a first redundant configuration. Alternatively, the pumps 124 , 126 may be arranged to collectively apply output pressure to the fluid and the fluid flows through respective check valves 132 , 134 to the outlet line 136 . The pumps 124, 126 may be controlled to provide both redundancy and common operation. In a different embodiment, the main pump unit may be configured to omit one of the pumps 124,126.

Fluid pumped through outlet line 136 is used to cool unit 122 . Cooling unit 122 may assume many configurations, including configurations similar to evaporator 30 of FIGS. 1 and 2 . The cooling unit 122 is disposed in an environment where it is desirable to remove heat from the environment in which the cooling unit 122 is located by transferring the heat to the fluid pumped through the outlet line 136 . Fluid from outlet line 136 enters cooling unit 122 at a first temperature and exits cooling unit 122 in line 140 at a high temperature. The fluid pumped through the cooling unit 122 may also change state from a liquid phase to a gaseous phase. A line 140 commonly referred to as an inlet line 140 returns working fluid to the main pump unit 120 .

Fluid in inlet line 140 is input to condenser 138 . Condenser 138 receives a working fluid in a first state having a first density (eg, gas) and rejects heat from the working fluid to an output fluid in a second state of higher density (eg, liquid). The fluid changes state from a gas phase to a liquid phase through condenser 138 . Condenser 138 receives chilled water supplied from chilled water inlet line 139 (shown as pump unit 120 in FIG. 3 ). Chilled water is circulated through condenser 138 to remove heat from the working fluid received from inlet line 140 . Chilled water is returned from condenser 138 to provide chilled water through chilled water outlet line 141 (shown in pump unit 120 of FIG. 3 ). The output of condenser 138 is output via return line 144 which is input to receiver 142 . The receiver 142 recovers the working fluid for use through the pump unit 120 . Receiver 142 returns working fluid to the respective pump 124 , 126 via receiver output line 143 . Bypass line 146 bypasses the receiver so that fluid flows from the outlet of condenser 138 directly to receiver output line 143 , thereby bypassing receiver 142 . Receiver output line 143 provides working fluid to pumps 124, 126 through respective pump inlet lines 148, 150.

In addition to the main pump units 120a, 120b, . . . , 120n, a redundant pump unit 120' is included in the pumped refrigerant cooling system 100 of FIG. 1 . The redundant pump unit 120' supplies the working fluid at a pressure as a result of which any main pump unit 120a, 120b, ..., 120n should become inoperative. In this manner, the pump unit 120' provides redundancy to another pump unit, thereby maintaining uptime and providing cooling functionality for any cooling unit 122 associated with the deactivated primary pump unit.

The redundant pump unit 120' is configured similarly to the pump unit 120 described above. The pump unit 120' also includes a liquid line 136' output to each of the cooling units 122a, 122b, ..., 122n. A liquid line 136' is connected to each liquid line 136a, 136b, ..., 136n via a respective gate valve 154a, 154b, ..., 154n. Redundant pump unit 120' also receives working fluid through vapor line 140'. The steam line 140' is connected to each of the steam lines 140a, 140b, ..., 140n via respective mixing valves 156a, 156b, ..., 156n. The redundant pump unit 120' also includes a redundant receiver link 158', which passes through each of the linked receivers 142a, 142b, ..., 142n of the respective valves 160a, 160b, ... 160n. The controller 162 sends and receives monitoring and control signals for selected components of the pumped refrigerant cooling system 100 in order to affect the control of the pumped refrigerant cooling system 100 .

The operation of the system is described with respect to Figures 4-7. When a unit becomes or must be out of service, because of different operating conditions of the main pump unit 120, a redundant unit 120' is activated to replace the out of service main pump unit. For example, if the primary pump unit 120a needs to fail, then the redundant pump unit 120' is activated to provide pump functionality for deactivating the primary pump unit 120a. When this occurs, valve 160a opens to connect receiver 142a to receiver 142', as shown in Figure 4, so that the pressures between receivers 142a and 142' are equalized. Equalization occurs via the receiver chain 158' indicated by the bold line in FIG. 4 . After a preset time period, the pressure is equalized between the receiver 142a of the primary pump unit 120a and the receiver 142' of the redundant pump unit 120'.

Once the pressures are equalized, the redundant pump unit 120' is activated to provide the pump function for the cooling unit 122a associated with the main pump unit 120a. As shown in FIG. 5, in order for redundant pump unit 120a to provide the pump function for cooling unit 122a, valve 156a is opened so that working fluid, typically in vapor form, output from cooling unit 122a is directed to redundant pumping unit 122a via vapor line 140'. Condenser 138' of remaining pump unit 120'. Also during the transition to redundant pump unit 120', valve 154a is opened so that liquid line 136' provides working fluid, typically in a liquid state, to cooling unit 122a. Switching of valves 156a and 154a enables redundant pump unit 120' to provide pumping functions for primary pump unit 120a. The redirected fluid flow is directed to the redundant pump unit 120' which provides for deactivating the pump function of the main pump unit 120a. This is shown by the bold lines in FIG. 5 . The main pump unit 120a can thus be deactivated. Receiver valve 160a is then closed.

Once the decision is made to restore the primary pump unit 120a, thereby requiring the failure of the redundant pump unit 120', a similar process to that described above occurs.

To begin the process of returning the deactivated primary pump unit 120a to an operational state, the receiver valve 160a is opened to allow pressure equalization between the receiver 142a of the pump unit 120a and the receiver 142' of the redundant pump unit 120'. This is represented in Figure 6, where the fluid flow in the receiver link 158' for equalizing pressure is shown with bold lines. In various embodiments, receiver valves 160 may be provided in a normally open configuration and selectively closed to isolate specific and associated receivers 142 . Once the pressures have equalized, the main pump unit 120a is then activated so that working fluid is pumped through the fluid circuit of the pump unit 120a. To produce this transition, valve 156a is adjusted to close the connection between the output of cooling unit 122a and redundant steam line 140a'. This directs fluid from the outlet of cooling unit 122a to the inlet of pump unit 120a and condenser 138a. Additionally, valve 154a is closed so that the outlet of pump unit 120a provides an input of working fluid to cooling unit 122a via liquid line 136a. Closing of valve 154a also shuts off the flow of working fluid on redundant steam line 136'. The receiver valve 160a of the pump unit 120a is also closed to sever the fluid connection between the receiver 142a of the pump unit 120a and the receiver 142' of the redundant pump unit 120'. Accordingly, the pump unit 120a resumes operation, as shown by the thick line in FIG. 7 .

FIG. 8 provides a flow diagram of a non-limiting embodiment for a switchover process from a primary pump unit to a redundant pump unit. Control begins at block 170 and proceeds to block 172 . Block 172 equalizes receiver pressure between the deactivated primary pump unit and the activated redundant pump unit. Control then passes to block 174, which activates the redundant pump unit. Once the redundant pump unit is activated, control passes to block 176 where a control valve is set to switch fluid flow to the redundant pump unit away from the primary pump unit. Control then passes to block 178 where the primary pump unit is deactivated. In some embodiments, following failure of the primary pump unit, control proceeds to block 180 where the primary receiver valve is closed. The process ends at block 182 .

9 depicts a block diagram of a non-limiting embodiment for returning a primary pump to an active state in communication with a cooling unit and deactivating a redundant pump unit. Control begins at block 190 and proceeds to block 192 , which equalizes the receivers for the respective redundant pump units that are deactivated and the primary pump units that are activated. Control then passes to block 194 where the primary pump unit is activated with the desired transition. With the primary pump unit activated, control passes to block 196, which changes the valves to switch fluid flow to the primary pump unit and away from the redundant pump unit. Control then passes to block 198 where the redundant pump unit is then deactivated. In some embodiments, following the failure of the redundant pump unit, control proceeds to block 200 where the primary receiver valve is closed. Control then passes to end block 202 .

Figure 10 depicts a cooling system 210 arranged in accordance with various embodiments. The cooling system 210 includes a pump unit 220 for providing fluid to be pumped to the cooling unit (not shown in FIG. 10 ). The pump unit 220 operates similarly to the pump unit 120 described above. The pump unit 220 contains built-in redundancy in various embodiments and may be a dual or parallel pair of pump units, valves and controllers sharing a common condenser and receiver.

Pump unit 220 provides pumped fluid through output line 136 to cooling unit or load 122 . The cooling unit is in an environment where it is desirable to remove heat from the environment in which the cooling unit is located by transferring the heat to the fluid pumped through outlet line 136 . As described above, fluid from output line 136 enters the cooling unit at a first temperature and exits the cooling unit through line 140 at an elevated temperature. The fluid pumped through the cooling unit may also change state from a liquid phase to a gaseous phase.

FIG. 10 also shows chilled water inlet line 139 and chilled water outlet line 141 . Chilled water is input to condenser 138 through inlet line 139 . Chilled water is supplied from a chilled water source (not shown in Figure 10), such as building chilled water. Chilled water passes through condenser 138 to effect heat transfer from fluid circulating in condenser 138 through outlet line 136 and inlet line 140 . Chilled water exits condenser 138 through chilled water outlet line 141 .

Chilled water outlet line 141 connects to redundant detection and control circuit 224 having a first circuit branch 226 and a second, redundant circuit branch 226'. It should be noted that the loop branches 226, 226' are arranged in a generally symmetrical configuration, and that any loop branch may be represented as a primary or redundant loop branch or may be referred to as a running and a dormant loop branch respectively. Each circuit branch 226, 226' comprises a pair of valves 232, 232' connected to the chilled water outlet line 141. The outputs of valves 232, 232' are combined and input to flow meter 236. In various embodiments, the valves 232, 232' may be spring return valves as normally closed.

In various embodiments, the control loop 224 also includes a pair of controllers 238, 238' that provide redundancy for the left and right pump units 220. Controller 238 communicates with valve 232 via control line 242 . Similarly, controller 238' communicates with valve 232' via control line 242'. Controller 238 communicates with pump 124 via control line 240 . Similarly, controller 238' communicates with pump 126 via control line 240'. In various embodiments, controller 238 also includes a signal line for monitoring variable flow valve 232' via signal line 246, and controller 238' monitors the state of variable flow valve 232 via signal line 246'. The controllers 238, 238' communicate via a connection 230, which may be a signal or data line.

In operation, the pump unit 220 functions as a redundant operating circuit sharing a common condenser 138 and receiver 142 . Controller 238, valve 232, and pump 124 and associated electrical and fluid lines comprise a first redundant portion of the circuit, and controller 238', valve 232' and pump 126 and associated electrical and fluid lines comprise a second redundant portion of the circuit. the remainder. In various embodiments, control selection between redundant portions of the loop occurs through controllers 238, 238' communicating over connection 230. Connection 230 may be a signal line in different embodiments, or a data line in other embodiments. In a different embodiment, the controllers 238, 238' arbitrate control by generating a signal on the connection 230 that keeps the other controller in a dormant state. For example, if controller 238 generates a signal on connection 230, controller 238' will remain in a dormant state as long as controller 238 generates a signal. If the controller 238 ceases generating a signal on the connection 230, the controller 238' will start and generate a signal on the connection 230 accordingly, which will keep the controller 238 in a dormant state. In various other embodiments, the controllers 238, 238' may communicate via the connection 230 by exchanging data in order to arbitrate control of the pump unit 220.

In various embodiments, the controller 238 may control and monitor various portions of its redundant circuit, including the valve 232, the pump unit 124, and associated connections and control lines. Controller 238' may similarly monitor components for various portions of its redundant loop. If the controller 238 detects a fault in any of its respective circuit components, including faults within the controller itself, the controller 238 may shut down, thereby transferring control to the controller 238'. The controller 238' operates similarly, and activates the controller 238 when the controller 238' detects a fault in its respective redundant loop portion.

In various embodiments, controllers 238, 238' control respective valves 232, 232', pumps 124, 126 and monitor flow meters 236. In a different embodiment, the controller 238 monitors the flow in the opposing circuit branch 238' to determine whether a disruption of flow has occurred. Likewise, in various embodiments, the controller 238' monitors the flow of fluid in opposing circuit branches to determine whether a disruption of flow has occurred. If an interrupt occurs, the relative control loop becomes active. As a non-limiting example, a controller 238 controls the valve 232 . Controller 238 also monitors the operation of flow valve 232' via signal line 246. Controller 238 operates to control flow through valve 232 . Controller 238' operates similarly with respect to valve 230' and valve 232. Similarly controller 238' controls valve 232'. Controller 238' also monitors the operation of flow valve 232 via signal line 246'. Controller 238' operates to control flow through valve 232'.

In various embodiments, the controllers 238, 238' can control the flow of fluid through the respective circuit branches 226, 226' and operate individually or collectively to control the flow of fluid at the outlet line 141. In various embodiments, one of the controllers 238, 238' may control the flow of fluid through its respective circuit branch 226, 226'. If a fault should occur at any loop branch element associated with a particular controller, fluid flow control can be assumed and controlled by another controller using another loop branch. In this different embodiment, fluid flows through only one of the circuit branches 226, 226'.

In various other embodiments, fluid flow may occur through each of the respective circuit branches 226, 226' so that the combined flow provides the desired flow of fluid through the chilled water outlet line 141. In this different embodiment, the fluid flow can be split so that about half of the fluid flow occurs through one circuit branch 226 and the other half occurs through the circuit branch 226 ′, thereby combining for the passage of chilled water All fluid flow required for outlet line 141. If either circuit branch 226, 226' fails, its circuit branch can be deactivated (failed) by its respective controller, and fluid flow through the other circuit branch can be increased to maintain the required fluid flow. The flow is through chilled water outlet line 141 .

FIG. 11 depicts a flowchart 250 demonstrating the operation of the redundant loop branch implementation of FIG. 10 . Control begins at start block 252 and proceeds to decision block 254 . At decision block 254, a test is performed to determine if a fault exists in the primary loop branch. The primary loop branch may optionally be determined as one of the loop branches 226, 226', leaving the remaining loop branches as redundant, secondary, or other loop branches. It may be assumed that loop branch 226 is a primary loop branch. If no fault occurs in primary loop branch 226, control returns to decision block 254 where the test is repeated. If a fault occurs in the primary loop branch 226, control proceeds to block 256 where the secondary loop branch 226' is switched. In a different embodiment, switching may then be effected by controller 238 stopping, which causes controller 238' to start running. In various other embodiments, control may terminate and return to 254 . In a different embodiment, control then passes to block 258 where a test is performed to determine if the loop branch fault has cleared. If not, then control returns to block 258 where the test is repeated. If the fault has cleared, control proceeds to block 260. At block 260, return to the primary circuit branch is accomplished by opening the respective shutoff valve 230 and variable flow valve 232 and closing the secondary valve 230' and closing or reducing fluid flow through the secondary flow valve 232'. Control then proceeds to block 262 where the process is complete.

Figure 12 depicts a block diagram 270 leading to a redundant solution when both circuit branches 226, 226' Control begins at start block 272 and proceeds to block 274 , which operates both circuit branches to share (equally or unequally) the flow through the chilled water outlet line 141 . Control then passes to decision block 276, which performs a test to determine whether a load change fault exists in one of the two circuit branches 226, 226'. If no load change or fault is detected, control returns to decision block 276, which repeats the test. If a load change or failure is detected, control proceeds to block 278 where flow is adjusted in the redundant or failed circuit branch by controlling the associated pumps and valves. Control proceeds to block 280 where the fluid flowing in the primary circuit is regulated to maintain flow through the chilled water outlet line 141 at the desired rate. Control passes to block 282 where a test is performed to determine if the fault in the faulty loop branch has been resolved. If the load variation or fault is not resolved, control returns to test block 282 where the test is repeated. If the load variation fault has been resolved, control proceeds to block 284 where fluid flow through the primary circulation branch is adjusted. Control proceeds to block 286, where the flow through the redundant circuit branches is adjusted so that both circuit branches 226, 226' share the fluid flowing through the outlet line 141. Control next proceeds to block 288 where the process is complete.

The foregoing description of the embodiments has been provided for purposes of illustration and description. It is not intended to be exhaustive or to limit the invention. Individual elements or features of a particular embodiment are generally not limited to that particular embodiment, but, where applicable, are interchangeable and can be used in a selected embodiment, even if not specifically shown or described. The same can also be varied in many ways. Such variations are not to be regarded as a departure from the invention, and all such modifications are intended to be included within the scope of the invention.

Claims (9)

1. a kind of cooling system, comprising:

Multiple primary cooling modules, each primary cooling module include the first pump for circularly cooling agent, and the first pump is with first Temperature provides refrigerant to evaporator, and the first condenser for receiving refrigerant from evaporator, the first Liquid acquisition Device receives liquid from the first condenser, is in the temperature higher than the first temperature, Mei Gechu by the received refrigerant of the first condenser Grade refrigerating module passes through corresponding evaporator circularly cooling agent；

Multiple first liquid receivers, the first liquid receiver is associated with corresponding primary cooling module and is used for from corresponding Primary cooling module condenser receive liquid condition refrigerant；With

Secondary cooling module, secondary cooling module include the second pump and the second condenser and for recycling the refrigerant Two liquid receivers, the second condenser receive refrigerant from evaporator, and second liquid receiver receives liquid from the second condenser, The temperature higher than the first temperature, one selected in each primary cooling module are in by the received refrigerant of the second condenser When a primary cooling module is deactivated, secondary cooling module is controlled to pass through the corresponding evaporator of selected primary cooling module Enable the secondary cooling module,

Wherein, it when enabling the secondary cooling module, is turned on by the fluid stream that receiver links, the receiver link The first liquid receiver of each of the multiple primary cooling module is fluidly connected to the second liquid receiver, to select Balance to selecting property selected respective primary refrigerating module corresponding first liquid receiver and the second liquid receiver it Between pressure.

2. cooling system according to claim 1 further includes being arranged in each first liquid receiver and second liquid receiver Between receiver link in receiver valve, so as to by means of the control of the first controller in each first liquid receiver and the Fluid flowing between two liquid receivers.

3. cooling system according to claim 1, further includes:

For controlling between corresponding evaporator inlet and a refrigerating module of primary cooling module and secondary cooling module The inlet valve of fluid flowing；With

Described in controlling in the primary cooling module in evaporator outlet and secondary cooling module and multiple refrigerating modules The outlet valve that fluid flows between one refrigerating module.

4. cooling system according to claim 1, further includes:

First valve, first valve have the entrance for the chilled water outlet pipeline for being connected to the first condenser；

Second valve in parallel with the first valve, and the second valve has a primary cooling module being connected in multiple refrigerating modules The first condenser chilled water outlet pipeline entrance；

The first controller associated with the first valve；With

Second controller associated with the second valve,

Wherein in the first mode, the first controller controls the first valve, and second controller controls the second valve, and in the second mould In formula, a controller of the first controller or second controller controls a respective valve in the second valve or the first valve.

5. cooling system according to claim 4, wherein the first controller and one primary in multiple refrigerating modules are cold But the first pump of module is associated, and the of one primary cooling module in second controller and multiple refrigerating modules Three pumps are associated, the first pump, the first valve and the first control of one primary cooling module in plurality of refrigerating module Device forms the first circuit, and the third of one primary cooling module in multiple refrigerating modules pump, the second valve and second are controlled Device processed forms second servo loop, and the cooperation of the first and second circuits is redundantly to control cooling system.

6. cooling system according to claim 4, wherein the first controller and second controller pass through electrical connection communication.

7. cooling system according to claim 6, wherein when a controller of the first controller or second controller starts When communicating between them, a controller of the first controller or second controller starts the component of communication control cooling system, And the control unit of the cooled system of another controller of the first controller or second controller is forbidden.

8. cooling system according to claim 4, wherein which controller the first controller and second controller communication to determine Control the particular elements of cooling system.

9. cooling system according to claim 4, wherein the first controller monitors the shape of at least one of the second valve or third pump State, and second controller monitors the state of at least one of the first valve or the first pump.