Pressure regulator assembly for coolant distribution unit

Abstract

The present disclosure relates to a pressure regulator assembly for a coolant distribution unit. An example embodiment relates to a pressure regulator assembly for a closed fluid loop of a CDU. The pressure regulator assembly has a cylinder having an internal volume and first and second hollow pistons slidably connected to the cylinder to divide the internal volume into a first volume portion having a cooling fluid, a second volume portion having a driver fluid, and a third volume portion having a compressible substance. The first volume portion is fluidically connected to the closed fluid loop. The first hollow piston is reciprocated by the compressible substance to maintain an operating pressure of the cooling fluid in the closed fluid loop. The second hollow piston is driven by the driver fluid in response to a predefined pressure drop of the cooling fluid during a predefined time period to inject additional cooling fluid from the first volume portion into the closed fluid loop to restore the pressure level of the cooling fluid to the operating pressure.

Description

Technical Field

[0001] Electronic devices (such as computers, networking devices, power supply units, etc.) generate heat during use. Cooling systems can be used to remove heat from the components of electronic devices to keep them within desired operating temperatures. For example, some cooling systems use a coolant distribution unit (CDU) with one or more circulating pumps to circulate cooling fluid in a closed fluid loop to remove heat from the components of electronic devices. Attached Figure Description

[0002] Various examples will be described below with reference to the accompanying figures.

[0003] Figure 1 A block diagram of a pressure regulator assembly according to an exemplary embodiment of the present disclosure is shown.

[0004] Figure 2A The illustration shows a block diagram of a data center environment having a coolant distribution unit and multiple electronic devices according to an exemplary embodiment of the present disclosure.

[0005] Figure 2B The illustration shows an example embodiment according to the present disclosure. Figure 2A A cross-sectional perspective view of the pressure regulator assembly of the CDU.

[0006] Figure 2C The illustration shows a connection to a drive fluid assembly according to an exemplary embodiment of the present disclosure. Figure 2B A perspective view of the pressure regulator assembly.

[0007] Figure 3 The diagram illustrates a portion of a data center environment having a coolant distribution unit and a controller, according to another exemplary embodiment of the present disclosure.

[0008] Figure 4 A cross-sectional perspective view of a pressure regulator assembly according to another exemplary embodiment of the present disclosure is illustrated.

[0009] Figure 5 The illustration shows a cross-sectional perspective view of a pressure regulator assembly according to yet another exemplary embodiment of the present disclosure.

[0010] Figure 6 The illustration shows a flowchart of a method for depicting an operating pressure regulator assembly according to an exemplary embodiment of the present disclosure, the pressure regulator assembly being used to regulate the operating pressure of cooling fluid in a coolant distribution unit. Detailed Implementation

[0011] The following detailed description refers to the accompanying drawings. For illustrative purposes, please refer to... Figure 1-6The components illustrated are used to describe certain examples. However, the functions of the illustrated components may overlap, and they may exist in fewer or more elements and components. Furthermore, the disclosed examples can be implemented in various environments and are not limited to the illustrated examples. Further, in conjunction with... Figure 6 The described sequence of operations is exemplary and not intended to be limiting. Where possible, the same reference numerals are used in the drawings and the following description to refer to the same or similar parts. However, it will be clearly understood that the drawings are for illustrative and descriptive purposes only. Although several examples are described in this document, modifications, adaptations, and other embodiments are possible. Therefore, the following detailed description does not limit the disclosed examples. Rather, the proper scope of the disclosed examples is defined by the appended claims.

[0012] As used herein, “operating pressure” refers to the pressure at which cooling fluid circulates through a circulating pump in a closed fluid loop within a coolant distribution unit (CDU). As used herein, “predefined pressure” refers to the threshold pressure of the cooling fluid at the inlet of the circulating pump required for circulation of the cooling fluid in the closed fluid loop at the operating pressure. As used herein, “minimum threshold pressure” refers to the minimum pressure of the cooling fluid at the inlet of the circulating pump required for circulation of the cooling fluid in the closed fluid loop at the operating pressure. As used herein, “predefined time” refers to the threshold time period during which the circulating pump can receive cooling fluid at a predefined pressure and pump it in the closed fluid loop at the operating pressure. As used herein, “predefined volume level” refers to the threshold volume level of the internal volume of a cylinder that can be used to contain cooling fluid. As used herein, “maximum threshold volume level” refers to the maximum portion of the internal volume of a cylinder that can be used to contain cooling fluid. As used herein, “minimum threshold volume level” refers to the minimum portion of the internal volume of a cylinder required to contain cooling fluid and maintain the operating pressure of the cooling fluid in the closed fluid loop. As used herein, “fluidly connected” means that two or more components are connected in a suitable manner such that fluid or at least a portion of a fluid can be transferred or flow directly or indirectly from one component to another.

[0013] In the case of a cooling system including a cooling fluid circulator (CDU) that circulates cooling fluid in a closed fluid loop, the cooling fluid may experience pressure (e.g., operating pressure) variations due to pressure spikes and / or thermal expansion and contraction. Such variations in operating pressure can cause cavitation in one or more circulating pumps, leading to pump failure. Additionally, the CDU may tend to lose a portion of its cooling fluid over time due to evaporation within the closed fluid loop and / or dripping from one or more pipe joints in the CDU. Therefore, such loss of cooling fluid can also gradually reduce the operating pressure of the cooling fluid in the closed fluid loop. When the operating pressure drops below a predetermined pressure over a predetermined time period, it can also cause cavitation in one or more circulating pumps, leading to pump failure. Furthermore, cavitation can also occur at certain pressure points in the piping, causing damage to the piping and thus premature CDU failure.

[0014] To address issues related to pressure variations in the cooling fluid within a closed-loop cooling unit (CDU), some cooling systems may include an accumulator within the CDU to regulate operating pressure changes in the cooling fluid. For example, an accumulator connected to the closed-loop may provide pressure relief in response to pressure spikes and / or thermal expansion and contraction of the cooling fluid, thus regulating pressure variations. Therefore, the accumulator assists in maintaining the operating pressure of the cooling fluid within the closed-loop. The accumulator may typically have a storage volume of working fluid (e.g., cooling fluid) within its internal volume at the operating pressure. In such cases, the accumulator connected to the closed-loop may push a portion of the stored cooling fluid into and / or pull a portion of the cooling fluid out of the closed-loop to regulate pressure variations within the closed-loop.

[0015] Similarly, to address issues related to cooling fluid loss in the closed-loop circuit of a CDU, some cooling systems may include a fluid reservoir within the CDU to inject a portion of the cooling fluid into the closed-loop circuit when the operating pressure drops below a predefined pressure over a predefined time period, thereby restoring the pressure level to the operating pressure. Therefore, a fluid reservoir with a storage volume of cooling fluid can be fluidly connected to the closed-loop circuit to inject a portion of the stored cooling fluid into the closed-loop circuit.

[0016] However, in such cooling systems, the stored coolant in the accumulator can remain stagnant for extended periods because the coolant circulating in the closed-loop circuit of the CDU may not experience frequent pressure changes. Similarly, the stored coolant in the reservoir can remain stagnant for long periods because a portion of the coolant circulating in the closed-loop circuit can be gradually lost over a long time. Typically, chemicals in the stored coolant are degradable and / or can be released from the stored coolant. Therefore, the stored coolant is degradable, causing it to lose certain properties, such as corrosive and bio-inhibitory properties. These properties are crucial for minimizing the degradation of the closed-loop circuit. As a result, when a portion of the stored coolant is pushed into and / or injected into the closed-loop circuit, it can inadvertently introduce bacteria and / or corrosive particles, thereby contaminating the entire mixture of coolant in the closed-loop circuit. Consequently, when such cooling systems are used to cool electronic devices, these devices may be forced to undergo unavoidable shutdowns to replace the contaminated coolant. Furthermore, when a cooling system requires components (e.g., accumulators) to regulate pressure and separate components (e.g., fluid reservoirs) to regulate the loss of cooling fluid, such a cooling system may be bulky, take up more space, and be expensive to maintain. Moreover, in order to maintain and replace the accumulators and fluid reservoirs, the electronic devices may be forced to undergo a separate shutdown.

[0017] A technical solution to the aforementioned problem may include providing a pressure regulator assembly for the closed fluid loop of the CDU. The pressure regulator assembly may include: a cylinder having an internal volume; and first and second hollow pistons slidably connected to the internal volume to divide the internal volume into a first volume portion having cooling fluid, a second volume portion having driving fluid, and a third volume portion having compressible material. The first volume portion is fluidly connected to the closed fluid loop to allow continuous flow of cooling fluid in the closed fluid loop via the pressure regulator assembly, thereby preventing stagnation of the cooling fluid.

[0018] The first piston can reciprocate through the compressible material stored in the third volume section to manage pressure (operating pressure) changes caused by pressure spikes and / or thermal expansion and contraction of the cooling fluid in the closed fluid circuit. Therefore, the third volume section with the compressible material and the first volume section with the cooling fluid, together with the first hollow piston, can act as an accumulator for the closed fluid circuit to maintain the operating pressure of the cooling fluid in the closed fluid circuit.

[0019] Furthermore, the second piston can be slidably driven by the driving fluid in response to a predefined pressure drop in the cooling fluid in the closed fluid loop during a predefined time period, to inject additional cooling fluid from the first volume portion into the closed fluid loop, thereby restoring the pressure level to the operating pressure. The predefined pressure drop during the predefined time period may be due to the loss of cooling fluid from the closed fluid loop or conduit of the CDU over a period of time. Therefore, the second volume portion with the driving fluid and the first volume portion with the cooling fluid, together with the second hollow piston, can act as a cooling fluid reservoir to restore the operating pressure of the cooling fluid in the closed fluid loop. Furthermore, the second volume portion with the driving fluid can directly or indirectly drive the compressible material via the first hollow piston to compress the compressible material, thereby simultaneously restoring the cooling fluid in the first volume portion to the operating pressure.

[0020] In one or more examples of this disclosure, the pressure regulator assembly can function as a combined component of an accumulator and a cooling fluid reservoir. Therefore, the pressure regulator assembly can simultaneously maintain the operating pressure of the cooling fluid in the closed fluid loop and restore the pressure level of the cooling fluid in the closed fluid loop to the operating pressure. Furthermore, compared to cooling systems that require separate accumulators and cooling fluid reservoirs, the pressure regulator assembly is easier to handle, cheaper, and requires less installation space. Moreover, electronics with a pressure regulator assembly are not forced to undergo separate shutdowns for maintenance and / or replacement of the accumulator and cooling fluid reservoir.

[0021] Therefore, in one or more examples of this disclosure, a pressure regulator assembly for a closed fluid loop of a coolant distribution unit (CDU) is disclosed. The pressure regulator assembly includes a cylinder, a first hollow piston, and a second hollow piston. The cylinder has an internal volume defined between an inlet and an outlet. The first and second hollow pistons are slidably connected to the cylinder to divide the internal volume into a first volume portion having cooling fluid, a second volume portion having a driving fluid, and a third volume portion having a compressible substance. The first volume portion is fluidly connected to the closed fluid loop of the CDU. The first hollow piston reciprocates with the compressible substance to maintain the operating pressure of the cooling fluid in the closed fluid loop. The second hollow piston is driven by the driving fluid in response to a sensor detecting a predefined pressure drop in the cooling fluid in the closed fluid loop during a predefined time period to inject additional cooling fluid from the first volume portion into the closed fluid loop, thereby regulating the loss of cooling fluid in the CDU and thereby restoring the pressure level of the cooling fluid in the closed fluid loop to the operating pressure.

[0022] Turn to the attached diagram. Figure 1A block diagram depicts a pressure regulator assembly 100 for a coolant distribution unit (CDU). It should be understood that... Figure 1 It is not intended to depict a particular shape, size or other structural detail accurately or to scale, and embodiments of the pressure regulator assembly 100 may have different numbers and arrangements of the components shown, and may also include other parts not shown.

[0023] like Figure 1 As shown, the pressure regulator assembly 100 includes a cylinder 102, a first hollow piston 104, and a second hollow piston 106. The cylinder 102 has an inlet 108, an outlet 110, and an internal volume 112 defined between the inlet 108 and the outlet 110. The first hollow piston 104 and the second hollow piston 106 are slidably connected to the cylinder 102 to divide the internal volume 112 into a first volume portion 114 having a cooling fluid 116, a second volume portion 118 having a driving fluid 120, and a third volume portion 122 having a compressible substance 124. The first hollow piston 104 includes a hollow rod section 104A and a hollow head section 104B extending from the hollow rod section 104A. Similarly, the second hollow piston 106 includes a hollow rod section 106A and a hollow head section 106B extending from the hollow rod section 106A. In some non-limiting examples, one of the first hollow piston 104 or the second hollow piston 106 may have only a hollow head section. In such examples, the hollow head section of one of the first hollow piston 104 or the second hollow piston 106 may slide relative to the hollow rod section of the other of the first hollow piston 104 or the second hollow piston 106. In some examples, the hollow rod section 104A may partially slide out of the pressure regulator assembly 100 through outlet 110 and is fluidly connected to a first hose 126A (e.g., a first flexible tube or a first rigid tube) of the closed fluid circuit 128. Similarly, the hollow rod section 106A may partially slide out of the pressure regulator assembly 100 through inlet 108 and is fluidly connected to a second hose 126B (e.g., a second flexible tube or a second rigid tube) of the closed fluid circuit 128.

[0024] The pressure regulator assembly 100 can be used to: i) maintain the operating pressure of the cooling fluid 116 in the closed fluid loop 128, and ii) restore the pressure level of the cooling fluid 116 in the closed fluid loop 128 to the operating pressure. For example, the pressure regulator assembly 100 can act as a combined accumulator and cooling fluid reservoir to simultaneously maintain the operating pressure of the cooling fluid 116 in the closed fluid loop 128 and restore the pressure level of the cooling fluid 116 in the closed fluid loop 128 to the operating pressure.

[0025] In some examples, the first volume portion 114 is fluidly connected to the closed fluid circuit 128 of the CDU via a first hollow piston 104 and a second hollow piston 106 to allow continuous flow of cooling fluid 116 in the closed fluid circuit 128, thereby preventing stagnation of cooling fluid 116 in the pressure regulator assembly 100. During operation of the CDU, the first hollow piston 104 can be reciprocated by a compressible material 124 to push a portion of the cooling fluid 116 into the closed fluid circuit 128 or pull that portion of the cooling fluid 116 into the first volume portion 114, thereby maintaining the operating pressure of the cooling fluid 116 in the closed fluid circuit 128. Thus, the pressure regulator assembly 100 can act as an accumulator without causing the cooling fluid 116 to stagnate in the first volume portion 114 of the cylinder 102. Furthermore, the second hollow piston 106 can be driven by the driver fluid 120 in response to a predefined pressure drop in the cooling fluid 116 in the closed fluid circuit 128 during a predefined time period, to inject additional cooling fluid 116 from the first volume portion 114 into the closed fluid circuit 128, thereby restoring the pressure level to the operating pressure. Thus, the pressure regulator assembly 100 can additionally act as a cooling fluid reservoir without causing the cooling fluid 26 to stagnate in the first volume portion 114 of the cylinder 102. Additionally, the driver fluid 120 can directly or indirectly drive the first hollow piston 104 to compress the compressible material within the third volume portion 122, thereby simultaneously restoring the compressible material 124 in the third volume portion 122 to the operating pressure.

[0026] Figure 2A A block diagram depicts a data center environment 230 having a coolant distribution unit (CDU) 250 and multiple electronic devices 280. Figure 2B Depicting Figure 2A A cross-sectional perspective view of the pressure regulator assembly 200 of the CDU 250. Figure 2C The fluid assembly connected to the drive fluid assembly 270 is depicted. Figure 2B A perspective view of the pressure regulator assembly 200. In the following description, for ease of illustration, a perspective view is also described. Figure 2A-2C It should be understood that... Figure 2A-2C This illustration is not intended to be accurate or to scale, depicting any particular shape, size, or other structural details, and embodiments of the data center environment 230 may have different numbers and arrangements of the components shown, and may also include other parts not shown. During operation of the data center environment 230, the plurality of electronic devices 280 may perform one or more workloads, and the CDU 250 may perform thermal management of the plurality of electronic devices 280.

[0027] refer to Figure 2AThe plurality of electronic devices 280 are disposed within the internal space of chassis 282. Further, CDU 250 and chassis 282 may be deployed within rack 232 of data center environment 230. In some examples, the CDU 250 deployed within rack 232 may be referred to as a rack-level CDU. In some other examples, data center environment 230 may include separate racks to deploy each of chassis 282 and CDU 250. In such examples, the CDU 250 deployed in a separate rack may be referred to as a centralized CDU. In such examples, the centralized CDU 250 may perform thermal management of one or more chassis deployed in one or more separate racks.

[0028] The plurality of electronic devices 280 may include computers (e.g., servers, storage devices), networking devices (e.g., wireless access points, network switches, routers), etc. Each of the plurality of electronic devices 280 may include: primary electronic components (not shown), such as a central processing unit (CPU), a graphics processing unit (GPU), a power supply chip, a memory chip; and secondary electronic components, such as capacitors, inductors, resistors, etc. Such electronic components may generate a significant amount of waste heat when performing one or more workloads. In such an example, the CDU 250 may be configured to dissipate the waste heat from each of the plurality of electronic devices 280 to enable the electronic components to function properly and to prevent damage to the electronic components due to waste heat.

[0029] The CDU 250 includes a pressure regulator assembly 200, a closed fluid loop 228, a circulating pump 254, a heat exchanger 256, and a cold plate (not shown). It can be noted herein that... Figure 2A The CDU 250 discussed in the examples may be referred to as a rack-mounted CDU. In some other examples, the CDU 250 may be a centralized CDU without departing from the scope of this disclosure.

[0030] The closed fluid loop 228 may include tubing (e.g., flexible or rigid tubing) that may connect to each other at multiple intersections to define a fluid flow path 258. The fluid flow path 258 directs the flow of cooling fluid 216 within the closed fluid loop 228 for thermal management of the plurality of electronic devices 280 deployed in the chassis 282. The fluid flow path 258 has a cooled fluid flow path 258A (or main fluid flow path) and a heated fluid flow path 258B connected to each other. The cooled fluid flow path 258A extends from the heat exchanger 256 to the plurality of electronic devices 280 via a pressure regulator assembly 200 and a circulation pump 254. The heated fluid flow path 258B extends from the plurality of electronic devices 280 to the heat exchanger 256. In one or more examples, a cooling fluid flow path 258A directs the flow of cooling fluid 216A from the heat exchanger 256 to the plurality of electronic devices 280, and a heating fluid flow path 258B directs the flow of heated fluid 216B from the plurality of electronic devices 280 to the heat exchanger 256.

[0031] exist Figure 2A In one example, the pressure regulator assembly 200 is disposed in a cooled fluid flow path 258A defined by a closed fluid loop 228. In some other examples, the pressure regulator assembly 200 may be disposed in an auxiliary fluid flow path 258C defined by the closed fluid loop 228. In some examples, the auxiliary fluid flow path 258C may protrude from the main fluid flow path 258A, extend parallel to the main fluid flow path 258A, and merge back into the main fluid flow path 258A. In such examples, the main fluid flow path 258A may bypass the pressure regulator assembly 200 and extend directly from the heat exchanger 256 to the circulation pump 254, and the auxiliary fluid flow path 258C may extend from the heat exchanger 256 to the circulation pump 254 via the pressure regulator assembly 200. In some examples, the pressure regulator assembly 200 located in the auxiliary fluid flow path 258D can avoid problems associated with pressure drop at the pump inlet 254A of the circulating pump 254, which may be caused by the pressure regulator assembly 200 located in the main fluid flow path 258A.

[0032] In one or more examples, the pressure regulator assembly 200 may act as a combined accumulator and cooling fluid reservoir to simultaneously maintain the operating pressure of the cooling fluid 216 in the closed fluid loop 228 and restore the pressure level of the cooling fluid 216 in the closed fluid loop 228 to the operating pressure. Reference Figure 2BThe pressure regulator assembly 200 includes a cylinder 202, a first hollow piston 204, and a second hollow piston 206. The cylinder 202 includes an inlet 208, an outlet 210, an internal volume 212 defined between the inlet 208 and the outlet 210, a first hollow connector section 202A projecting outward from the outlet 210, and a second hollow connector section 202B projecting outward from the inlet 208. In some examples, the first hollow connector section 202A may be connected to a first hose 226A of the CDU 250 (e.g., a first flexible tube or a first rigid tube), and the second hollow connector section 202B may be connected to a second hose 226B of the CDU 250 (e.g., a second flexible tube or a second rigid tube). The first hollow piston 204 includes a first hollow rod section 204A and a first hollow head section 204B extending from the first hollow rod section 204A. Similarly, the second hollow piston 206 includes a second hollow rod section 206A and a second hollow head section 206B extending from the second hollow rod section 206A. The first hollow piston 204 is slidably connected to the cylinder 202 via an outlet 210, and the second hollow piston 206 is slidably connected to the cylinder 202 via an inlet 208, such that the first hollow head section 204B and the second hollow head section 206B face each other and are spaced apart within the cylinder 202. Therefore, when the first hollow piston 204 and the second hollow piston 206 are disposed in the cylinder 202, they divide the internal volume 212 of the cylinder 202 into a first volume portion 214, a second volume portion 218, and a third volume portion 222. The first volume portion 214 is defined between the first hollow head section 204B and the second hollow head section 206B. The second volume portion 218 is defined between the second hollow head section 206B and the inlet 208 of the cylinder 202. Similarly, the third volume portion 222 is defined between the first hollow head section 204B and the outlet 210 of the cylinder 202. In some examples, the first hollow head section 204B may reciprocate within the cylinder 202, and the first hollow rod section 204A may reciprocate within the cylinder 202 and the first hollow connector section 202A via the outlet 210. Similarly, the second hollow head section 206B may reciprocate within the cylinder 202, and the second hollow rod section 206A may reciprocate within the cylinder 202 and the second hollow connector section 202B via the inlet 208. As discussed herein, the first hollow connector section 202A can be connected to the first hose 226A of the CDU 250, and the second hollow connector section 202B can be connected to the second hose 226B of the CDU.

[0033] like Figure 2AAs shown, a first volume portion 214 is filled with cooling fluid 216, a second volume portion 218 is filled with driver fluid 220, and a third volume portion 222 is filled with compressible material 224. In one or more examples, the first volume portion 214 is further fluidly connected to a closed fluid circuit 228, such as a cooled fluid flow path 258A, via a first hollow connector section 202A, a first hollow piston 204, a second hollow piston 206, and a second hollow connector section 202B. Therefore, the cooling fluid 216 filled in the first volume portion 214 can flow continuously in the closed fluid circuit 228, thereby preventing stagnation of the cooling fluid 216 within the first volume portion 214 of the pressure regulator assembly 200.

[0034] The cylinder 202 further includes a first opening 234 formed on a section of the cylinder 202 corresponding to the second volume portion 218. In such examples, the pressure regulator assembly 200 drives the fluid assembly 270 (e.g., Figure 2A and Figure 2C (As shown) is connected to the second volume portion 218 via a first opening 234. The first opening 234 may be either in an open position to provide inflow of driving fluid into the second volume portion 218 or in a closed position to provide outflow of driving fluid from the second volume portion 218, as discussed in detail below. In some examples, the driving fluid 220 pumped into the second volume portion 218 may additionally drive the first hollow piston 204 along a first direction 10 via the second hollow piston 206 and the cooling fluid 216 in the first volume portion 214, as discussed in more detail below. In one or more examples, each of the cooling fluid 216 and the driving fluid 220 is an incompressible fluid. Because the driving fluid 220 in the second volume portion 218 is an incompressible fluid, the driving fluid 220 prevents the second hollow piston 206 from sliding along a second direction 20 opposite to the first direction 10 when the compressible material 224 pushes the cooling fluid 216 in the first volume portion 214 along a second direction 20 via the first hollow piston 204.

[0035] like Figure 2AAs shown, the pressure regulator assembly 200 further includes a pair of first sealing elements 236A, a pair of second sealing elements 236B, a pair of third sealing elements 236C, and a pair of fourth sealing elements 236D. The pair of first sealing elements 236A is connectable to the outlet 210 of the cylinder 202. In this example, the pair of first sealing elements 236A seals the interface between the outlet 210 and the outer surface of the first hollow rod section 204A of the first hollow piston 204 to prevent compressible material 224 from leaking from the third volume portion 222 to the outside of the pressure regulator assembly 200 or to prevent cooling fluid 216 from leaking from the first hollow connector section 202A into the third volume portion 222. The pair of second sealing elements 236B is connectable to the first hollow head section 204B of the first hollow piston. The second sealing element 236B seals the interface between the inner surface of the cylinder 202 and the first hollow section 204B to prevent compressible material 224 from leaking from the third volume portion 222 into the first volume portion 214 of the cylinder 202 or to prevent cooling fluid 216 from leaking from the first volume portion 214 into the third volume portion 222.

[0036] The third sealing element 236C can be coupled to the inlet 208 of the cylinder 202. The third sealing element 236C seals the interface between the inlet 208 and the outer surface of the second hollow rod section 206A of the second hollow piston 206 to prevent the driving fluid 220 from leaking from the second volume portion 218 to the outside of the pressure regulator assembly 200 or to prevent the cooling fluid 216 from leaking from the second hollow connector section 202B into the second volume portion 218. The fourth sealing element 236D can be coupled to the second hollow head section 206B of the second hollow piston 206. The fourth sealing element 236D seals the interface between the inner surface of the cylinder 202 and the second hollow head section 206B to prevent the driving fluid 220 from leaking from the second volume portion 218 into the first volume portion 214 of the cylinder 202 or to prevent the cooling fluid 216 from leaking from the first volume portion 214 into the second volume portion 218.

[0037] refer to Figure 2A and Figure 2C As discussed herein, the driver fluid assembly 270 of the pressure regulator assembly 200 is connected via a first opening 234 to the second volume portion 218 of the cylinder 202. The driver fluid assembly 270 includes a main pipe 240A, a bypass conduit 240B, a driver pump 242 connected to the main pipe 240A, a valve 244, and a driver fluid reservoir 246. The main pipe 240A is connected to the first opening 234 and the driver fluid reservoir 246 via the driver pump 242. The valve 244 is connected to the main pipe 240A and disposed between the driver pump 242 and the first opening 234. The bypass conduit 240B is connected to the valve 244 and the driver fluid reservoir 246.

[0038] In some examples, the driver pump 242 is a fluid pump. Valve 244 is a three-way valve with multiple positions, such as a shut-off position, a first on position, and a second open position. In some examples, valve 244 can be manually switched between multiple positions. In such examples, the driver pump 242 can be manually opened or closed. In some other examples, valve 244 can be automatically switched between multiple positions. In such examples, the driver pump 242 can be controlled by a controller (…). Figure 2A-2C (Not shown) It automatically opens or closes. In the shut-off position of valve 244 and the closed position of the first opening 234, valve 244 can stop the flow of driver fluid 220 from the second volume portion 218 to the driver fluid reservoir 246, and vice versa. In the first open position of valve 244 and the open position of the first opening 234, valve 244 can establish an inlet flow path 248A from the driver fluid reservoir 246 through the driver pump 242, the main pipe 240A, and the first opening 234 to the second volume portion 218. In the second open position of valve 244 and the open position of the first opening 234, valve 244 can establish an outlet flow path 248B from the second volume portion 218 through the first opening 234, a portion of the main pipe 240A, and the bypass conduit 240B to the driver fluid reservoir 246. The driver fluid reservoir 246 may have driver fluid 220 stored in its internal volume.

[0039] In one or more examples, during the setup of the pressure regulator assembly 200 for use in the CDU 250, the pressure regulator assembly 200 may first be configured to a charged state. In some examples, the pressure regulator assembly 200 may be charged by the following steps: i) filling the second volume portion 218 with driver fluid 220, ii) filling the third volume portion 222 with compressible material 224, and iii) filling the first volume portion 214 with cooling fluid 216. In one or more examples, the compressible material 224 filled in the third volume portion 222 may be at atmospheric pressure. In some examples, at atmospheric pressure, the driver fluid 220 may occupy up to 10% of the internal volume 212 of the cylinder 202, and the compressible material 224 may occupy up to 50% of the internal volume 212 of the cylinder 202. In such examples, when the first hollow connector section 202A and the first opening 234 are in the closed position, cooling fluid 216 fills the first volume portion 214 via the second hollow connector section 202B. Therefore, the cooling fluid 216 filling the first volume portion 214 can compress the compressible material 224 in the third volume portion 222 via the first hollow piston 204 and the second hollow piston 206 until the compressible material 224 is compressed to the operating pressure. In some examples, when the compressible material 224 is compressed to the operating pressure, it can occupy up to 30% of the internal volume 212 of the cylinder 202. In one or more examples, when the cooling fluid 216 is filled in the first volume portion 214, the driver fluid 220 in the second volume portion 218 prevents the second hollow piston 206 from sliding along the second direction 20, thereby allowing the cooling fluid 216 filled in the first volume portion 214 to compress the compressible material 224 in the third volume portion 222 via the first hollow piston 204 until the compressible material 224 is compressed to the operating pressure. Therefore, when the compressible material 224 is compressed to the operating pressure in the third volume portion 222, the pressure regulator assembly 200 can be interpreted as being in a charged state. As used herein, "charged state" may refer to the physical condition of the cylinder 202 such that approximately 60% of its internal volume 212 is filled with cooling fluid 216, approximately 10% of its internal volume 212 is filled with driver fluid 220, and approximately 30% of its internal volume 212 is filled with compressible material 224. In other words, when the pressure regulator assembly 200 is charged, the internal volume 212 of the cylinder 202 can be divided into a ratio of approximately 60% of the first volume portion 214, approximately 10% of the second volume portion 218, and approximately 30% of the third volume portion 222.

[0040] In one or more examples, the pressure regulator assembly 200 in a charged state may be connected to a closed fluid circuit 228. For example, a first hollow connector section 202A of the cylinder 202 is connected to a first hose 226A, and a second hollow connector section 202B is connected to a second hose 226B, such that the first volume portion 214 is fluidly connected to a cooled fluid flow path 258A of the closed fluid circuit 228 in the CDU 250. In such examples, when the pressure regulator assembly 200 is connected to the closed fluid circuit 228, the cooling fluid 216 in the closed fluid circuit 228 and the first volume portion 214 may be at an operating pressure.

[0041] refer to Figure 2A-2B Cooling fluid 216 can flow from heat exchanger 256 to circulation pump 254 via pressure regulator assembly 200. In other words, a first volume portion 214 of cylinder 202 is fluidly connected via a first hollow piston 204 and a second hollow piston 206 to a cooled fluid flow path 258A of a closed fluid flow path 258 to allow continuous flow of cooling fluid 216 (e.g., cooled fluid 216A from heat exchanger 256 to circulation pump 254 via pressure regulator assembly 200). Therefore, pressure regulator assembly 200 of this disclosure prevents stagnation of cooling fluid 216 within pressure regulator assembly 200, thereby overcoming one or more problems associated with stagnation of cooling fluid 216 in cooling fluid reservoirs and / or accumulators. In one or more examples, cooling fluid 216 is a mixture of water and propylene glycol and additives, a dielectric fluid, or water, and drive fluid 220 is a mixture of propylene glycol, hydraulic fluid, water, or a mixture of water and propylene glycol. The compressible material 224 is one of a spring (e.g., a coil spring), an elastomeric component, or air. Figure 2A-2C In one example, the compressible material 224 is a helical spring. In one or more examples, each of the cooling fluid 216 and the driving fluid 220 is an incompressible fluid. In some examples, the mixture of water and propylene glycol may be in a ratio from about 95:5% to about 50:50%. Further, additives may include corrosion inhibitors and biocides.

[0042] In one or more examples, the first hollow piston 204 may i) reciprocate as the compressible material 224 expands to push a portion of the cooling fluid 216 from the first volume portion 214 into the cooled fluid flow path 258A of the closed fluid circuit 228, and ii) reciprocate as the compressible material 224 compresses to pull that portion of the cooling fluid 216 from the cooled fluid flow path 258A of the closed fluid circuit 228 into the first volume portion 214, thereby maintaining the operating pressure of the cooling fluid 216 in the closed fluid circuit 228, as discussed in more detail below. Further, the second hollow piston 206 may be slidably driven by the driver fluid 220 along a first direction 10 to reduce the first volume portion 214 (or increase the second volume portion 218) and inject a portion of the cooling fluid 216 from the first volume portion 214 into the cooled fluid flow path 258A of the closed fluid circuit 228, thereby compensating for the loss of cooling fluid 216 in the CDU 250, as discussed in more detail below. Additionally, the first hollow piston 204 can be slidably driven by the driver fluid 220 along the first direction 10 to compress the compressible material 224, thereby simultaneously restoring the compressible material 224 in the third volume portion 222 to the operating pressure, as discussed in more detail below.

[0043] Return to reference Figure 2A The circulation pump 254 is a fluid pump. Pump inlet 254A receives cooled fluid 216A guided from heat exchanger 256 via pressure regulator assembly 200. The circulation pump 254 pumps the cooled fluid 216A from pump inlet 254A to the plurality of electronic devices 280 via cooled fluid flow path 258A. In such examples, cooled fluid flow path 258A may be further connected to cooling conduits (not shown) arranged in series or parallel within chassis 282. These cooling conduits guide the flow of cooled fluid 216A to a cold plate, thermally coupled to a corresponding electronic component of each electronic device 280 to transfer waste heat from the corresponding electronic component to the cooled fluid 216A, thereby producing heated fluid 216B. The cooling conduits may later guide the heated fluid 216B from the plurality of electronic devices 280 to the heated fluid flow path 258B.

[0044] A heated fluid flow path 258B can guide the flow of heated fluid 216B from the plurality of electronic devices 280 to a heat exchanger 256. In one or more examples, the heat exchanger 256 dissipates waste heat from the heated fluid 216B and regenerates cooled fluid 216A. In some examples, the heat exchanger 256 may be a liquid heat exchanger, a back-door heat exchanger, etc. In one or more examples, the heat exchanger 256 may receive facility-cooled fluid 238A from the data center environment 230 to dissipate waste heat from the heated fluid 216B and regenerate cooled fluid 216A. For example, the heat exchanger 256 may indirectly transfer waste heat from the heated fluid 216B to the facility-cooled fluid 238A and regenerate both cooled fluid 216A and facility-heated fluid 238B. The heat exchanger 256 may later direct the regenerated cooled fluid 216A to the pump inlet 254A of the circulation pump 254 via a pressure regulator assembly 200.

[0045] even though Figure 2A The CDU 250 depicted in the example has a single pressure regulator assembly 200 connected to a closed fluid circuit 228. In some other examples, the CDU 250 may also include multiple pressure regulator assemblies without departing from the scope of this disclosure. In some examples, the single pressure regulator assembly 200 may be too large to be retrofitted within the available space of the CDU 250 due to one of the stroke lengths of the first hollow piston 204 and / or the second hollow piston 206, the diameter of the cylinder 202, or a combination thereof. Therefore, the multiple smaller pressure regulator assemblies can be retrofitted within the available space of the CDU 250 instead of a single pressure regulator assembly 200 to overcome the aforementioned problems related to the available space of the CDU 250. In such examples, the total internal volume of the multiple smaller pressure regulator assemblies may need to be matched to the internal volume of the single pressure regulator assembly 200. In some examples, depending on the cooling requirements of the multiple electronic devices 280, the multiple smaller pressure regulator assemblies may be connected to the closed fluid circuit 228 in a series configuration, a parallel configuration, or a combination thereof.

[0046] refer to Figure 2A and Figure 2BDuring operation of the data center environment 230, the pressure regulator assembly 200 can regulate changes in the operating pressure of the cooling fluid 216 in the closed fluid loop 228. For example, the pressure regulator assembly 200 can provide pressure relief in response to changes in operating pressure caused by pressure spikes and / or thermal expansion and contraction of the cooling fluid 216 in the closed fluid loop 228. Pressure spikes and / or thermal expansion and contraction can occur due to excessively high or moderate rates of waste heat generated by the electronics 280 while performing one or more workloads. The pressure regulator assembly 200 can ensure that a positive pressure is maintained within the closed fluid loop 228 (e.g., at pump inlet 254A) to guide the flow of the cooling fluid 216 within the closed fluid loop 228 without any problems associated with cavitation in the circulation pump 254 and the piping of the CDU 250.

[0047] For example, the plurality of electronic devices 280 may generate a nominal amount of waste heat when performing one or more of the workloads. Therefore, when handling such a nominal amount of waste heat, the cooling fluid 216 guided in the closed fluid loop 228 can be maintained at the operating pressure by the compressible material 224 in the third volume portion 222. Thus, this state of the pressure regulator assembly 200 can be referred to as the normal operating state. However, sometimes, due to variations in power consumption rate when performing one or more workloads, the plurality of electronic devices 280 may generate excessive or moderate amounts of waste heat. Therefore, when handling such excessive or moderate amounts of waste heat, the operating pressure of the cooling fluid 216 in the closed fluid loop 228 may fluctuate, thus causing the compressible material 224 in the third volume portion 222 to expand or compress in order to maintain the operating pressure of the cooling fluid 216 in the closed fluid loop 228.

[0048] For example, excessive waste heat can cause pressure spikes and / or thermal expansion in the cooling fluid 216, resulting in an increase in the operating pressure of the cooling fluid 216 in the closed fluid loop 228. In some examples, excessive waste heat can be generated due to overuse of major electronic components to perform workloads (e.g., graphics-intensive workloads). In such examples, the compressible material 224 can be compressed by the sliding movement of the first hollow head section 204B of the first hollow piston 204 along the first direction 10 to draw a portion of the cooling fluid 216 from the closed fluid loop 228 into the first volume portion 214, thus maintaining the operating pressure of the cooling fluid 216 in the closed fluid loop 228. Therefore, the pressure regulator assembly 200 can move from a normal operating state (or an expansion operating state) to a compression operating state to maintain the operating pressure of the cooling fluid 216 in the closed fluid loop 228. In such examples, the portion of cooling fluid 216 drawn into the first volume portion 214 can additionally apply pressure to the second hollow piston 206 to move the second hollow plunger 206 along the second direction 20. However, the incompressible driver fluid 220 filling the second volume portion 218 can apply counter-pressure to the second hollow piston 206, thereby preventing the second hollow plunger 206 from moving along the second direction 20. In some examples, when the pressure regulator assembly 200 is in compression operation, the compressible material 224 can be compressed up to 10% of the internal volume 212 of the cylinder 202 to maintain the operating pressure of the cooling fluid 216 in the closed fluid circuit 228. Therefore, the pressure regulator assembly 200 can prevent problems associated with cavitation in the circulation pump 254 and the piping of the CDU 250.

[0049] Furthermore, a moderate amount of waste heat can cause thermal contraction of the cooling fluid 216, resulting in a decrease in the operating pressure of the cooling fluid 216 in the closed fluid circuit 228. In some examples, a moderate amount of waste heat may be generated due to the normal use of major electronic components to perform the workload. In such examples, the compressible material 224 may expand, causing the first hollow head section 204B of the first hollow piston 204 to slide along the second direction 20 and push this portion of the cooling fluid 216 from the first volume portion 214 into the closed fluid circuit 228, thus maintaining the operating pressure of the cooling fluid 216 in the closed fluid circuit 238. Therefore, the pressure regulator assembly 200 can move from a compression operation state (or a normal operation state) to an expansion operation state to maintain the operating pressure of the cooling fluid 216 in the closed fluid circuit 228. In such examples, the portion of the cooling fluid 216 pushed from the first volume portion 214 into the closed fluid circuit 228 may additionally apply pressure to the second hollow piston 206 to move the second hollow plunger 206 along the second direction 20. However, the incompressible driving fluid 220 filling the second volume portion 218 can exert a counterpressure on the second hollow piston 206, thereby preventing the second hollow plunger 206 from moving along the second direction 20. In some examples, when the pressure regulator assembly 200 is in expansion operation, the compressible material 224 can be expanded by up to 50% of the internal volume 212 of the cylinder 202 to maintain the operating pressure of the cooling fluid 216 in the closed fluid circuit 228. Therefore, the pressure regulator assembly 200 can prevent problems associated with cavitation in the circulation pump 254 and the piping of the CDU 250.

[0050] In some examples, when the plurality of electronic devices 280 resume generating a nominal amount of waste heat, the cooling fluid 216 can return from a thermally contracted or thermally expanded state to a thermally normal state within the closed fluid loop 228. In such examples, when the cooling fluid 216 returns from a thermally expanded state to a thermally normal state within the closed fluid loop 228, the compressible material 224 can be expanded to allow the pressure regulator assembly 200 to return from a compressed operating state to a normal operating state. Therefore, the compressible material 224 can push this portion of the cooling fluid 216 back from the first volume portion 214 into the closed fluid loop 228, thereby maintaining the operating pressure of the cooling fluid 216 in the closed fluid loop 228. Similarly, when the cooling fluid 216 returns from a thermally contracted state to a thermally normal state within the closed fluid loop 228, the compressible material 224 can be compressed to allow the pressure regulator assembly 200 to return from an expanded operating state to a normal operating state. Therefore, the compressible material 224 can pull this portion of the cooling fluid 216 back from the closed fluid circuit 228 into the first volume portion 214, thereby maintaining the operating pressure of the cooling fluid 216 in the closed fluid circuit 228.

[0051] In one or more examples, the CDU 250 may tend to lose a portion of the cooling fluid 216 over time due to evaporation within the closed fluid loop 228 and / or dripping from one or more pipe joints of the CDU 250. Therefore, such loss of cooling fluid 216 can gradually reduce the operating pressure of the cooling fluid 216 in the closed fluid loop 228. When the operating pressure drops below a predefined pressure at the pump inlet 254A of the circulating pump 254 during a predefined time period, it can cause cavitation in the circulating pump 254, leading to pump damage. Furthermore, cavitation can occur at certain pressure points in the pipe joints of the CDU 250, resulting in damage to the piping of the CDU 250 and thus premature failure of the CDU 250. Additionally, as the operating pressure decreases in the closed fluid loop 228, the compressible material 224 can also expand to push a portion of the cooling fluid 216 in the first volume portion 214 into the closed fluid loop 228 to manage the operating pressure in the closed fluid loop 228. Therefore, the compressible material 224 can remain in an expanded operating state and cannot handle changes in operating pressure due to the thermal contraction of the cooling fluid 216 until the compressible material 224 returns to its normal operating state. In one or more examples, the second hollow piston 206 can be actuated (e.g., pushed or slid) by the driver fluid 220 in response to a predefined pressure drop in the cooling fluid 216 in the closed fluid circuit 228 during a predefined time period. For example, when the operating pressure drops below the predefined pressure, the driver fluid 220 can drive the second hollow piston 206 to slide along the first direction 10. Thus, the second hollow piston 206 can reduce the first volume portion 214 of the cylinder 202 and inject additional cooling fluid (e.g., a portion of the cooling fluid 216) from the first volume portion 214 into the closed fluid circuit 228, thereby restoring the pressure level of the cooling fluid 216 in the closed fluid circuit 228 to the operating pressure, as described below. Figure 3 This is discussed in more detail in the examples. Therefore, the pressure regulator assembly 200 can additionally prevent problems associated with cavitation in the piping of the circulation pump 254 and CDU 250. In one or more examples, the driver fluid 220 can also drive the first hollow piston 204 to compress the compressible material 224, thereby simultaneously restoring the compressible material 224 in the third volume portion 222 to the operating pressure, as described below. Figure 3This is discussed in more detail in the examples. Therefore, the compressible material 224 can recover from an expanded operating state to a normal operating state, thereby enabling the pressure regulator assembly 200 to handle operating pressure variations caused by pressure spikes and / or thermal expansion and contraction of the cooling fluid 216. In some examples, the operating pressure can range from about 10 psi to about 150 psi, the predefined pressure drop can be about 10% of the operating pressure, and the predefined time period can be about 1 minute. Therefore, the pressure regulator assembly 200 can act as a combined accumulator and cooling fluid reservoir. In other words, the pressure regulator assembly 200 can simultaneously maintain the operating pressure of the cooling fluid 216 in the closed fluid loop 228 and restore the pressure level of the cooling fluid 216 in the closed fluid loop to the operating pressure.

[0052] Figure 3 A block diagram depicts a portion of a data center environment 330, including a CDU 350 and a controller 360. The data center environment 330 may additionally include multiple electronic devices (not shown), as described herein. Figure 2A As discussed in the examples. It should be understood that, Figure 3 It is not intended to depict a particular shape, size or other structural detail accurately or to scale, and implementations of the data center environment 330 may have different numbers and arrangements of the components shown, and may also include other parts not shown.

[0053] It can be noted that the plurality of electronic devices may be substantially similar to Figure 2A Multiple electronic devices 280, without departing from the scope of this disclosure. Furthermore, the CDU 350 is substantially similar to... Figure 2A The CDU 250. For example, the CDU 350 includes a closed fluid loop 328, a pressure regulator assembly 300, a circulating pump 354, a heat exchanger (not shown), a cooling component (not shown), a driver fluid assembly 370, a supplemental cooling fluid assembly 390, a sensor (e.g., a pressure sensor 362), and a limit switch 364. It can be noted that when used with, for example... Figure 2A Compared to other components / devices of the CDU 250 shown in the example, the supplemental cooling fluid assembly 390 is an additional component / device in the CDU 350. Therefore, for the sake of brevity, the following description of the CDU 350 does not further describe the closed fluid loop 328, the circulating pump 354, the heat exchanger, the cooling components, and the drive fluid assembly 370, and such non-description should not be considered as a limitation of this disclosure.

[0054] The pressure regulator assembly 300 includes a cylinder 302, a first hollow piston 304, and a second hollow piston 306, as shown in... Figure 2A-2CAs discussed in the example, cylinder 302 includes an internal volume 312 defined between an inlet 308 and an outlet 310. A first hollow piston 304 and a second hollow piston 306 are slidably connected to cylinder 302 via outlet 310 and inlet 308, respectively, to divide the internal volume 312 into a first volume portion 314, a second volume portion 318, and a third volume portion 322. The first volume portion 314 is filled with cooling fluid 316, the second volume portion 318 is filled with driving fluid 320, and the third volume portion 322 is filled with compressible material 324. The first volume portion 314 is fluidly connected to a closed fluid circuit 328 via the first hollow piston 304 and the second hollow piston 306. Figure 3 The pressure regulator assembly 300 additionally includes a second opening 352 formed on another section of the cylinder 302 corresponding to the first volume portion 314. In such examples, a supplemental cooling fluid assembly 390 is connected to the first volume portion 314 via the second opening 352, as discussed in detail below.

[0055] like Figure 2C As noted in the example, the driver fluid assembly 370 of Figure 2 also includes a main pipe 340A, a bypass pipe 340B, a driver pump 342 connected to the main pipe 340A, a valve 344, and a driver fluid reservoir 346. In this example, the main pipe 340A is connected to the first opening 334 and the driver fluid reservoir 346 via the driver pump 342. Further, the valve 344 is connected to the main pipe 340A and disposed between the driver pump 342 and the first opening 334. The bypass pipe 340B is connected to the valve 344 and the driver fluid reservoir 346. As discussed above (refer to...), Figure 2A-2C The driver fluid assembly 370 can be used to pump driver fluid 320 into the second volume portion 318 of the pressure regulator assembly 300. The pumped driver fluid 320 can drive the second hollow piston 306 to inject an additional portion of cooling fluid 316 from the first volume portion 314, thereby compensating for the loss of cooling fluid 316 in the closed fluid circuit 328 of the CDU 350 and restoring the pressure level of the cooling fluid 316 in the closed fluid circuit 328 to the operating pressure.

[0056] In one or more examples, the supplemental cooling fluid assembly 390 includes a supplemental conduit 392, a supplemental cooling fluid reservoir 394, and a supplemental pump 396 connected to the supplemental conduit 392. In some examples, the supplemental pump 396 is a fluid pump. The supplemental conduit 392 is connected via the supplemental pump 396 to the second opening 352 and the supplemental cooling fluid reservoir 394. In one or more examples, the supplemental cooling fluid assembly 390 is used to restore the pressure regulator assembly 300 from a discharged state to a charged state. As used herein, "discharged state" may refer to another physical condition of the cylinder 302 where approximately 20% of its internal volume 312 is filled with cooling fluid 316, approximately 50% of its internal volume 312 is filled with driver fluid 320, and approximately 30% of its internal volume 312 is filled with compressible material 324. In other words, in the discharged state of the pressure regulator assembly 300, the internal volume 312 of the cylinder 302 can be divided into a ratio of approximately 20% of the first volume portion 314, approximately 50% of the second volume portion 318, and approximately 30% of the third volume portion 322.

[0057] As discussed herein, CDU 350 may tend to lose a portion of its cooling fluid 316 over time due to evaporation within the closed fluid loop 328 and / or dripping from one or more pipe joints in CDU 350. This loss of cooling fluid 316 can thus gradually reduce the operating pressure of the cooling fluid 316 within the closed fluid loop 328. When the operating pressure drops below a predefined pressure at the pump inlet 354A of the circulating pump 354 during a predefined time period, it can cause cavitation in the circulating pump 354, leading to pump damage. Furthermore, cavitation can occur at certain pressure points in the pipe joints of CDU 350, causing damage to the piping of CDU 350 and consequently premature CDU 350 failure. Additionally, when the operating pressure drops in the closed fluid loop 328, the compressible material 324 can also expand to push a portion of the cooling fluid 316 in the first volume portion 314 into the closed fluid loop 328 to manage the operating pressure in the closed fluid loop 328. Therefore, the compressible material 324 can cause the pressure regulator assembly 300 to remain in an expanded operating state and cannot handle changes in operating pressure due to the thermal contraction of the cooling fluid 316 until the compressible material 324 is compressed to allow the pressure regulator assembly 300 to return to normal operating conditions.

[0058] Therefore, in one or more examples, the second hollow piston 306 is driven by the driver fluid 320 in response to a predefined pressure drop in the cooling fluid 316 in the closed fluid circuit 328 during a predefined time period, to restore i) the cooling fluid 316 in the closed fluid circuit and ii) the compressible material 324 in the third volume portion to the operating pressure. In some examples, the valve 344 first moves from the off position to the first open position to establish an inlet flow path 348A from the driver fluid reservoir 346 via the first opening 334 and the main guide pipe 340A to the second volume portion 318. Later, in the first open position of the valve 344, the driver pump 342 is activated to pump the driver fluid 320 from the driver fluid reservoir 346 into the second volume portion 318 via the inlet flow path 348A. In this example, the driver fluid 320 pumped into the second volume portion 318 slidably drives the second hollow piston 306 along the first direction 10 and pushes a portion of the cooling fluid 316 from the first volume portion 314 into the closed fluid circuit 328 until the pressure of the cooling fluid 316 is restored to the operating pressure. Therefore, the first volume portion 314 is reduced to inject this portion of the cooling fluid 316 from the first volume portion 314 into the closed fluid circuit 328, thereby restoring the pressure level to the operating pressure. Thus, the pressure regulator assembly 300 can additionally prevent problems associated with cavitation in the piping of the circulation pump 354 and CDU 350. Additionally, the driver fluid 320 pumped into the second volume portion 318 indirectly drives the first hollow piston 304 along the first direction 10 via the second hollow piston 306 and the cooling fluid 316 in the first volume portion 314 to compress the compressible material 324 in the third volume portion 322 and restore the compressible material 324 to the operating pressure in the third volume portion 322. Therefore, when the compressible material 324 is compressed within the third volume portion 322, the compressible material can cause the pressure regulator assembly 300 to return from an expansion operation state to a normal operation state, thereby enabling the pressure regulator assembly 300 to handle operating pressure changes caused by pressure spikes and / or thermal expansion and contraction of the cooling fluid 316.

[0059] In one or more examples, over a period of time, the pressure regulator assembly 300 can move from a charged state to a discharged state by gradually adding an additional portion of cooling fluid 316 from the first volume portion 314 to the closed fluid loop 328 to compensate for the loss of cooling fluid 316 in the closed fluid loop 328 of the CDU 350 and to restore the pressure level of the closed fluid loop 328 to the operating pressure. Therefore, to restore the pressure regulator assembly 300 to the charged state, the valve 344 is first moved from the shut-off position to the second open position to establish an outlet flow path 348B from the second volume portion 318 via the first opening 334, a portion of the main pipe 340A, and the bypass conduit 340B to the drive fluid reservoir 346. Then, in the second open position of the valve 344, in response to the limit switch 364 detecting a minimum threshold volume level of cooling fluid in the first volume portion 314, the supplementary pump 396 is activated to pump supplementary cooling fluid 316A from the supplementary cooling fluid reservoir 394 into the first volume portion 314. In such examples, supplemental cooling fluid 316A pumped into the first volume portion 314 slidably drives the second hollow piston 306 along a second direction 20 opposite to the first direction 10 and discharges a portion of the driver fluid 320 from the second volume portion 318 into the driver fluid reservoir 346 via the outlet flow path 348B. In some examples, this portion of the driver fluid 320 discharged into the driver fluid reservoir 346 may correspond (or match) to the portion of the supplemental cooling fluid 316A filled into the first volume portion 314. Therefore, the addition (or pumping) of supplemental cooling fluid 316A into the first volume portion 314 may assist the pressure regulator assembly 300 in restoring the pressure regulator assembly 300 to a charged state.

[0060] exist Figure 3 In the examples, controller 360 is shown as being located within data center environment 330. In some other examples, controller 360 may be located outside data center environment 330. In one or more examples, controller 360 may be located within a data center management server accessible to an administrator of data center environment 330. Those skilled in the art will understand that controller 360 may include processing resources and machine-readable media (e.g., memory) to facilitate the performance of the functions described herein. In some examples, processing resources may be physical processors, such as central processing unit (CPU), microprocessors, and / or other hardware devices suitable for performing the functions described herein. In some examples, the machine-readable media is non-transitory and is alternatively referred to as non-transitory machine-readable media. Controller 360 is communicatively coupled to drive pump 342, supplemental pump 396, and valve 344.

[0061] Pressure sensor 362 is disposed on closed fluid loop 328. For example, pressure sensor 362 is located at pump inlet 354A and communicatively coupled to controller 360. Pressure sensor 362 is configured to periodically detect the operating pressure of cooling fluid 316 at pump inlet 354A and generate a first set of input signals 368A and a second set of input signals 368B to controller 360, which indicate the operating pressure of cooling fluid 316 at pump inlet 354A during a predefined time period. Pressure sensor may later transmit each of the first set of input signals 368A and the second set of input signals 368B to controller 360 separately.

[0062] Limit switch 364 is disposed on cylinder 302 and communicatively connected to controller 360. For example, limit switch 364 is positioned near inlet 308 of cylinder 302. Limit switch 364 may further include a first electromechanical object 366A and a second electromechanical object 366B. The first electromechanical object 366A may be positioned near the free end of hollow rod section 306A, and the second electromechanical object 366B may be positioned near the hollow head section 306B of second hollow piston 306. Limit switch 364 can detect the position of second hollow piston 306 when the first electromechanical object 366A or the second electromechanical object 366B approaches limit switch 364. In some examples, limit switch 364 can detect a threshold position when the first electromechanical object 366A approaches limit switch 364. For example, when the second hollow piston 306 slides within the cylinder 302 along the first direction 10 and reaches a threshold position, the limit switch 364 can detect the presence of the first electromechanical object 366A. It may be noted herein that the threshold position indicates a minimum threshold volume level of the cooling fluid 316 in the first volume portion 314. When the second electromechanical object approaches the limit switch 364, the limit switch 364 can detect a predefined position. When the second hollow piston 306 slides within the cylinder 302 along the second direction 20 and reaches a predefined position, the limit switch 364 can detect the presence of the second electromechanical object 366B. It may be noted herein that the predefined position indicates a maximum threshold volume level of the cooling fluid 316 in the first volume portion 314. In some examples, the minimum threshold volume level is approximately 20% of the internal volume 312 of the cylinder 302, and the predefined volume level is approximately 60% of the internal volume 312 of the cylinder 302. Therefore, the limit switch 364 can generate a third input signal 384A indicating a threshold position (or the discharge state of the pressure regulator assembly 300) or a fourth input signal 384B indicating a predefined position (or the charge state of the pressure regulator assembly 300), and transmit the third input signal 384A or the fourth input signal 384B to the controller 360.

[0063] In some examples, the driver fluid assembly 370 and the supplemental cooling fluid assembly 390 can be configured to operate automatically to perform their intended functions. For example, the controller 360 may receive a first set of input signals 368A from a pressure sensor 362, which indicates the operating pressure at the pump inlet 354A during a predefined time period. The controller 360 may compare the received pressure data with pressure data stored in its memory to determine whether the pressure data received during the predefined time period is equal to or greater than a predefined pressure (e.g., a minimum threshold pressure). If the controller 360 determines that the pressure data received during the predefined time period is equal to the predefined pressure, the controller 360 may send a first control signal 372A to valve 344 and a second control signal 374A to driver pump 342. In some examples, upon receiving the first control signal 372A, valve 344A may move from a shut-off position to a first open position to establish an inlet flow path 348A from driver fluid reservoir 346 to the second volume portion 318. After valve 344 has moved to the first open position, a second control signal 374 can trigger driver pump 342 to pump driver fluid 320 from driver fluid reservoir 346 into second volume portion 318 via inlet flow path 348A. Adding driver fluid 320 to second volume portion 318 can slidably drive second hollow piston 306 along first direction 10 to reduce first volume portion 314 (or increase second volume portion 318) and inject additional portion of cooling fluid 316 from first volume portion 314 into closed fluid circuit 328. Further, adding driver fluid 320 to second volume portion 318 can slidably drive first hollow piston 304 along first direction 10 to compress compressible material 324 and shift pressure regulator assembly 300 from expansion operation state to normal operation state.

[0064] In one or more examples, the driver pump 342 may continuously pump driver fluid 320 into the second volume portion 318 until the pressure levels of the cooling fluid 316 and compressible material 324 in the closed fluid loop 328 return to the operating pressure. For example, the controller 360 may receive a second set of input signals 368B from the pressure sensor 362, indicating the operating pressure at the pump inlet 354A during a predefined time period. The controller 360 may compare the received pressure data with stored pressure data to determine whether the pressure data received during the predefined time period is equal to or greater than a predefined pressure (e.g., a minimum threshold pressure). If the controller 360 determines that the pressure data received during the predefined time period is greater than the predefined pressure, the controller 360 may send a third control signal 374B to the driver pump 342 and a fourth control signal 372B to the valve 344. In some examples, upon receiving the third control signal 374B, the driver pump 342 may stop pumping driver fluid 320 from the driver fluid reservoir 346 into the second volume portion 318. After the drive pump 342 has stopped pumping drive fluid 320 into the second volume portion 318, the fourth control signal 372B can instruct valve 344 to move from the first open position to the shut-off position to stop drive fluid 320 from flowing from drive fluid reservoir 346 into the second volume portion 318. Therefore, the drive fluid assembly 370 can automatically manage the loss of cooling fluid 316 in the closed fluid loop 328 of the CDU 350 and restore the pressure levels of the cooling fluid 316 and compressible material 324 in the closed fluid loop 328 to the operating pressure.

[0065] When the first electromechanical object 366A on the second hollow piston 306 approaches the limit switch 364, the controller 360 may further receive a third input signal 384A from the limit switch 364. The third input signal 384A may indicate a threshold position (or the discharge state of the pressure regulator assembly 300). Therefore, upon receiving the third input signal 384A, the controller 360 may generate a fifth control signal 372C to the valve 344 and a sixth control signal 386A to the supplementary pump 396. In some examples, upon receiving the fifth control signal 372C, the valve 344 may move from a shut-off position to a second open position to establish an outlet flow path 348B from the second volume portion 318 to the driver fluid reservoir 346. After the valve 344 has moved to the second open position, the sixth control signal 386A may trigger the supplementary pump 396 to pump supplementary cooling fluid 316A from the supplementary cooling fluid reservoir 394 into the first volume portion 314. Adding supplemental cooling fluid 316A to the first volume portion 314 allows the second hollow piston 306 to be slidably driven along a second direction 20 opposite to the first direction 10, thereby reducing the second volume portion 318 (or increasing the first volume portion 314) and discharging a portion of the driver fluid 320 from the second volume portion 318 into the driver fluid reservoir 346 via the outlet flow path 348B.

[0066] In one or more examples, the replenishment pump 396 may continuously pump replenishment cooling fluid 316A into the first volume portion 314 until the volume levels of cooling fluid 316 and replenishment cooling fluid 316A in the first volume portion 314 increase from a minimum threshold volume level to a predefined volume level. For example, when the second electromechanical object 366B on the second hollow piston 306 approaches the limit switch 364, the controller 360 may receive a fourth input signal 384B from the limit switch 364. The fourth input signal 384B may indicate a predefined position (or the charging state of the pressure regulator assembly 300). Therefore, upon receiving the fourth input signal 384B, the controller 360 may generate a seventh control signal 386B to the replenishment pump 396 and an eighth control signal 372D to the valve 344. In some examples, upon receiving the seventh control signal 386B, the replenishment pump 396 may stop pumping replenishment cooling fluid 316A from the replenishment cooling fluid reservoir 394 into the first volume portion 314. After the supplemental pump 396 has stopped pumping supplemental cooling fluid 316A into the first volume portion 314, the eighth control signal 372D can instruct valve 344 to move from the second open position to the cut-off position to stop the flow of driver fluid 320 from the second volume portion 318 into the driver fluid reservoir 346. Therefore, the supplemental cooling fluid assembly 390 can automatically refill the supplemental cooling fluid 316A into the first volume portion 314 of cylinder 302 to move the pressure regulator assembly 300 from the discharge state to the charge state.

[0067] Figure 4 A cross-sectional perspective view of a pressure regulator assembly 400 is depicted. The pressure regulator assembly 400 includes a cylinder 402, a first hollow piston 404, and a second hollow piston 406. The cylinder 402 includes an internal volume 412 defined between an inlet 408 and an outlet 410. The first hollow piston 404 and the second hollow piston 406 are slidably connected to the cylinder 402 via the inlet 408 and the outlet 410, respectively, to divide the internal volume 412 into a first volume portion 414, a second volume portion 418, and a third volume portion 422. Figure 4In this example, cylinder 402 further includes a hollow connector section 402A projecting from outlet 410. Inlet 408 can be directly connected to an inlet hose of a closed fluid circuit (not shown). Outlet 410 can be connected to an outlet hose of the closed fluid circuit via hollow connector section 402A. First hollow piston 404 includes a first hollow rod section 404A and a first hollow head section 404B extending from the first hollow rod section 404A. Second hollow piston 406 includes a second hollow rod section 406A and a second hollow head section 406B extending from the second hollow rod section 406A. The first hollow rod section 404A of the first hollow piston 404 retracts within the second hollow piston 406. In this type of example, the first hollow piston 404 can reciprocate within cylinder 402 and the second hollow piston 406. The second hollow piston 406 can reciprocate within cylinder 402 and hollow connector section 402A. The first volume portion 414 is defined between the first hollow section 404B and the inlet 408. The second volume portion 418 is defined between the second hollow section 406B and the outlet 410 of the cylinder 402. Similarly, the third volume portion 422 is defined between the first hollow section 404B and the second hollow section 406B of the cylinder 402.

[0068] In one or more examples, a first volume portion 414 may be filled with cooling fluid, a second volume portion 418 may be filled with driver fluid, and a third volume portion 422 may be filled with compressible material 424 (e.g., a spring). In such examples, the first volume portion 414 may be fluidly connected to a closed fluid circuit via a first hollow piston 404, a second hollow piston 406, and a hollow connector section 402A. Therefore, the cooling fluid filled in the first volume portion 414 can flow continuously in the closed fluid circuit, thereby preventing stagnation of the cooling fluid within the first volume portion 414 of the pressure regulator assembly 400. The cylinder 402 further includes a first opening 434 formed on a section of the cylinder 402 corresponding to the second volume portion 418. In such examples, a driver fluid assembly of the pressure regulator assembly 400 may be connected to the second volume portion 418 via the first opening 434.

[0069] In one or more examples, the first hollow piston 404 may i) reciprocate as the compressible material 424 expands to push a portion of the cooling fluid from the first volume portion 414 into the closed fluid circuit, and ii) reciprocate as the compressible material 424 compresses to pull that portion of the cooling fluid from the closed fluid circuit into the first volume portion 414, thereby maintaining the operating pressure of the cooling fluid in the closed fluid circuit. In an example embodiment, the compressible material 424 may directly push the first hollow piston 404 along a first direction 10 to push that portion of the cooling fluid from the first volume portion 414 into the closed fluid circuit. Similarly, the compressible material 424 may be compressed by a sliding movement of the first hollow piston 404 along a second direction 20, caused by the pushing of that portion of the cooling fluid from the closed fluid circuit into the first volume portion 414. Thus, the pressure regulator assembly 400 can handle pressure spikes and / or thermal expansion and contraction of the cooling fluid in the closed fluid circuit.

[0070] Furthermore, the second hollow piston 406 can be slidably driven along the first direction 10 by a driver fluid in response to a predefined pressure drop of the cooling fluid in the closed fluid loop during a predefined time period. In some examples, the driver fluid is pumped into the second volume portion 418 via the first opening 434 to drive the second hollow piston 406 along the first direction 10 and reduce the first volume portion 414. For example, the second hollow piston 406 can slidably push the first hollow piston 404 via a compressible substance 424 filled in the third volume portion 422 to reduce the first volume portion 414. Thus, the reduction of the first volume portion 414 can result in the injection of a portion of the cooling fluid from the first volume portion 414 into the closed fluid loop to compensate for the loss of cooling fluid in the CDU, thereby restoring the operating pressure of the cooling fluid in the closed fluid loop. Additionally, the second hollow piston 406 slidably pushes the compressible substance 424 to compress the compressible substance 424 and restore the compressible substance 424 in the third volume portion 422 to the operating pressure.

[0071] Figure 5 A cross-sectional perspective view of a pressure regulator assembly 500 is depicted. The pressure regulator assembly 500 includes a cylinder 502, a first hollow piston 504, and a second hollow piston 506. The cylinder 502 includes an internal volume 512 defined between an inlet 508 and an outlet 510. The first hollow piston 504 and the second hollow piston 506 are slidably connected to the cylinder 502 via the outlet 510 and the inlet 508, respectively, to divide the internal volume 512 into a first volume portion 514, a second volume portion 518, and a third volume portion 522. Figure 5In the example, cylinder 502 further includes a hollow connector section 502A projecting from outlet 510. Inlet 508 can be directly connected to an inlet hose of a closed fluid circuit (not shown). Outlet 510 can be connected to an outlet hose of the closed fluid circuit via hollow connector section 502A. First hollow piston 504 includes a first hollow head section 504B or sleeve. Second hollow piston 506 includes a second hollow rod section 506A and a second hollow head section 506B extending from the second hollow rod section 506A. Second hollow piston 506 can reciprocate within cylinder 502 and hollow connector section 502A. First hollow piston 504 can reciprocate relative to the second hollow rod section 506A of second hollow piston 506. First volume portion 514 is defined between the second hollow head section 506B and inlet 508. The second volume portion 518 is defined between the first hollow section 504B and the second hollow section 506B of the cylinder 502. The third volume portion 522 is defined between the first hollow section 504B of the cylinder 502 and the outlet 510.

[0072] In one or more examples, a first volume portion 514 may be filled with cooling fluid, a second volume portion 518 may be filled with driver fluid, and a third volume portion 522 may be filled with compressible material 524 (e.g., a spring). In such examples, the first volume portion 514 may be fluidly connected to a closed fluid circuit via a first hollow piston 504, a second hollow piston 506, and a hollow connector section 502A. Therefore, the cooling fluid filled in the first volume portion 514 can flow continuously in the closed fluid circuit, thereby preventing stagnation of the cooling fluid within the first volume portion 514 of the pressure regulator assembly 500. The cylinder 502 further includes a first opening 534 formed on a section of the cylinder 502 corresponding to the second volume portion 518. In such examples, a driver fluid assembly (not shown) of the pressure regulator assembly 500 may be connected to the second volume portion 518 via the first opening 534.

[0073] In one or more examples, the first hollow piston 504 may i) reciprocate as the compressible material 524 expands to push a portion of the cooling fluid from the first volume portion 514 into the closed fluid loop, and ii) reciprocate as the compressible material 524 compresses to pull that portion of the cooling fluid from the closed fluid loop into the first volume portion 514, thereby maintaining the operating pressure of the cooling fluid in the closed fluid loop. In an example embodiment, the compressible material 524 may push the second hollow piston 506 along the second direction 20 via the first hollow piston 504 and the driving fluid to push that portion of the cooling fluid from the first volume portion 514 into the closed fluid loop. Similarly, the compressible material 524 may be compressed by a slidable movement of the first hollow piston 504 along the first direction 10, caused by the portion of the cooling fluid being pushed from the closed fluid loop into the first volume portion 514. In some examples, the portion of the cooling fluid pushed into the first volume portion 514 can indirectly compress the compressible substance 524 via the second hollow piston 506, the driving fluid, and the first hollow piston 504. Therefore, the pressure regulator assembly 500 can handle pressure spikes and / or thermal expansion and contraction of the cooling fluid in a closed fluid loop.

[0074] Furthermore, the second hollow piston 506 can be slidably driven along the second direction 20 by a driver fluid in response to a predefined pressure drop of the cooling fluid in the closed fluid loop during a predefined time period. In some examples, the driver fluid is pumped into the second volume portion 518 via the first opening 534 to drive the second hollow piston 506 along the second direction 20 and reduce the first volume portion 514. Thus, the reduction of the first volume portion 514 can result in the injection of a portion of the cooling fluid from the first volume portion 514 into the closed fluid loop to compensate for the loss of cooling fluid in the CDU, thereby restoring the operating pressure of the cooling fluid in the closed fluid loop. Additionally, the driver fluid pumped into the second volume portion 518 can slidably drive the first hollow piston 504 along the first direction 10 to compress the compressible material and restore the compressible material in the third volume portion 522 to the operating pressure.

[0075] Figure 6 This is a flowchart depicting a method 600 for operating a pressure regulator assembly used to manage the operating pressure of the cooling fluid in a closed fluid loop of a CDU and to regulate losses of cooling fluid in the CDU to restore the operating pressure of the cooling fluid in the closed fluid loop. It should be noted herein that, for example, method 600 is combined with... Figure 2A-2C The description is as follows. Method 600 begins at block 602 and continues to block 604.

[0076] At block 604, method 600 includes guiding the flow of cooling fluid in a closed fluid loop of a CDU via a pressure regulator assembly, the pressure regulator assembly comprising: a cylinder having an internal volume; and a first hollow piston and a second hollow piston slidably connected to the cylinder to divide the internal volume into a first volume portion having cooling fluid, a second volume portion having driving fluid, and a third volume portion having compressible material. In such an example, the first volume portion is fluidly connected to the closed fluid loop via the first and second hollow pistons to allow continuous flow of cooling fluid in the closed fluid loop via a cooling fluid reservoir. Because the cooling fluid flows continuously in the internal volume (i.e., the first volume portion) of the cooling fluid reservoir, stagnation of cooling fluid does not occur in the pressure regulator assembly. Therefore, the pressure regulator assembly of this disclosure overcomes one or more problems associated with stagnation of cooling fluid stored in existing fluid reservoirs. Method 600 continues to block 606.

[0077] At block 606, method 600 includes reciprocating a first hollow piston with a compressible material to maintain the operating pressure of the cooling fluid in the closed fluid circuit. In some examples, reciprocating the first hollow piston includes sliding the first hollow piston to push a portion of the cooling fluid from a first volume portion into the closed fluid circuit when the compressible material expands, and sliding the first cavity piston to pull that portion of the cooling fluid from the closed fluid circuit into the first volume portion when the compressible material compresses, to maintain the operating pressure. Thus, the pressure regulator assembly can handle pressure spikes and / or thermal expansion and contraction of the cooling fluid in the closed fluid circuit. Method 600 continues to block 608.

[0078] At block 608, method 600 includes: detecting a predefined pressure drop of cooling fluid in a closed fluid loop during a predefined time period. In some examples, the CDU may include a sensor (e.g., a pressure sensor located at the pump inlet of a circulation pump connected to the closed fluid loop) to detect the predefined pressure drop of cooling fluid at the pump inlet. In such examples, the pressure sensor may periodically detect the operating pressure of the cooling fluid at the pump inlet and generate a signal during the predefined time period. In some examples, the sensor may communicate these signals to a controller or data center management server communicatively coupled to the sensor. In one or more examples, these signals may indicate the operating pressure of the cooling fluid at the pump inlet during the predefined time period.

[0079] In some examples, the administrator or controller of the data center management server can compare the received stress data with the stored stress data to determine whether the stress data received during a predefined time period is equal to a predefined stress (e.g., minimum threshold stress) or whether the stress data received during the predefined time period is greater than the predefined stress. If the administrator or controller determines that the stress data received during the predefined time period is greater than the predefined stress, i.e., "No" at block 608, then method 600 ends at block 612. If the administrator or controller determines that the stress data received during the predefined time period is equal to the predefined stress, i.e., "Yes" at block 608, then method 600 can move to block 610.

[0080] At block 610, method 600 includes: driving a second hollow piston by a driver fluid in response to a predefined pressure drop of cooling fluid in a closed fluid loop during a predefined time period to inject additional cooling fluid from a first volume portion into the closed fluid loop, thereby restoring the pressure level to the operating pressure. In some examples, a controller may send a control signal to the driver fluid assembly to automatically drive the second hollow piston, as in... Figure 3 As discussed in the examples. In some other examples, the administrator may manually adjust the driver fluid assembly to drive the second hollow piston. In some examples, at block 610, method 600 may further include: driving the first hollow piston by the driver fluid to simultaneously restore the compressible material in the third volume portion to the operating pressure. Thus, the pressure regulator assembly compensates for the loss of cooling fluid in the closed fluid loop of the CDU and restores the pressure levels of the cooling fluid in the closed fluid loop and the compressible material in the third volume portion to the operating pressure. Method 600 ends at block 612.

[0081] Various features illustrated in the examples described herein can be implemented in the pressure regulator assembly, which can function as a combined accumulator and cooling fluid reservoir. The pressure regulator assembly can simultaneously maintain the operating pressure of the cooling fluid in the closed fluid loop and restore the pressure level of the cooling fluid in the closed fluid loop to the operating pressure. Furthermore, compared to cooling systems requiring separate accumulators and cooling fluid reservoirs, the pressure regulator assembly is easier to handle, cheaper, and requires less installation space. Moreover, a system with electronics and the pressure regulator assembly is not forced to undergo separate shutdowns for maintenance and / or replacement of the accumulator and cooling fluid reservoir.

[0082] In the foregoing description, numerous details have been set forth to provide an understanding of the subject matter disclosed herein. However, this implementation may be practiced without some or all of these details. Other implementations may include modifications, combinations, and variations of the details discussed above. The appended claims are intended to cover such modifications and variations.

Claims

1. A pressure regulator assembly, the pressure regulator assembly comprising: A cylinder, which has an internal volume; as well as A first hollow piston and a second hollow piston, slidably connected to the cylinder to divide the internal volume into a first volume portion having a cooling fluid, a second volume portion having a driving fluid, and a third volume portion having a compressible substance. The first volume portion is fluidly connected to a closed fluid loop of a coolant distribution unit (CDU), wherein the first hollow piston reciprocates via the compressible material to maintain the operating pressure of the cooling fluid in the closed fluid loop, and wherein the second hollow piston is driven by the actuator fluid in response to a predefined pressure drop of the cooling fluid in the closed fluid loop during a predefined time period to inject additional cooling fluid from the first volume portion into the closed fluid loop, thereby restoring the pressure level to the operating pressure. Each of the cooling fluid and the driving fluid is an incompressible fluid.

2. The pressure regulator assembly according to claim 1, wherein, The first hollow piston: i) reciprocates as the compressible material expands to push a portion of the cooling fluid from the first volume portion into the closed fluid circuit; and ii) reciprocates as the compressible material compresses to pull the portion of the cooling fluid from the closed fluid circuit into the first volume portion, thereby maintaining the operating pressure.

3. The pressure regulator assembly according to claim 1, wherein, The first hollow piston is further fluid-driven by the actuator to compress the compressible material, thereby simultaneously restoring the compressible material in the third volume portion to the operating pressure.

4. The pressure regulator assembly according to claim 3, wherein, The second volume portion is fluidly connected to a driver fluid reservoir via a first opening in the cylinder, and wherein the driver fluid is pumped from the driver fluid reservoir into the second volume portion, thereby: i) driving the second hollow piston to inject the additional cooling fluid from the first volume portion into the closed fluid circuit; and ii) driving the first hollow piston to compress the compressible material until the pressure levels of the cooling fluid in the closed fluid circuit and the compressible material in the third volume portion return to the operating pressure.

5. The pressure regulator assembly according to claim 1, wherein, The first volume portion is fluidly connected to a supplemental cooling fluid reservoir via a second opening in the cylinder, and wherein supplemental cooling fluid is pumped from the supplemental cooling fluid reservoir into the first volume portion in response to a minimum threshold volume level of the cooling fluid in the first volume portion, until the volume levels of the cooling fluid and the supplemental cooling fluid in the first volume portion increase from the minimum threshold volume level to a predefined volume level.

6. The pressure regulator assembly according to claim 5, wherein, The supplemental cooling fluid pumped into the first volume portion drives the second hollow piston to refill the first volume portion with the supplemental cooling fluid and discharge a portion of the drive fluid from the second volume portion into a drive fluid reservoir, which is fluidly connected to the second volume portion via a first opening in the cylinder.

7. The pressure regulator assembly according to claim 1, wherein, The cooling fluid is a mixture of water and propylene glycol and additives, a dielectric fluid, or water; the drive fluid is propylene glycol, a hydraulic fluid, water, or a mixture of water and propylene glycol; the compressible material is a compressible spring, an elastomer component, or a compressible fluid; the operating pressure is in the range of 10 psi to 150 psi; the predefined pressure drop is 10% of the operating pressure; the predefined time period is 1 minute; the minimum threshold volume level is 20% of the internal volume; and the predefined volume level is 60% of the internal volume.

8. A coolant distribution unit (CDU) comprising: Closed fluid loop; A circulating pump, which is connected to the closed fluid loop for pumping cooling fluid in the closed fluid loop; A sensor is positioned at the inlet of the circulating pump to detect a predefined pressure drop of the cooling fluid in the closed fluid loop during a predefined time period; as well as Pressure regulator assembly, comprising: Cylinder, which has an internal volume; and A first hollow piston and a second hollow piston, slidably connected to the cylinder to divide the internal volume into a first volume portion containing the cooling fluid, a second volume portion containing the driving fluid, and a third volume portion containing the compressible substance. The first volume portion is fluidly connected to the closed fluid loop to allow continuous flow of the cooling fluid in the closed fluid loop via the pressure regulator assembly. The first hollow piston reciprocates through the compressible material to maintain the operating pressure of the cooling fluid in the closed fluid loop. The second hollow piston is driven by the actuator fluid in response to a sensor detecting a predefined pressure drop in the cooling fluid in the closed fluid loop during a predefined time period to inject additional cooling fluid from the first volume portion into the closed fluid loop, thereby restoring the pressure level to the operating pressure. Each of the cooling fluid and the driving fluid is an incompressible fluid.

9. The CDU according to claim 8, wherein, The first hollow piston: i) reciprocates as the compressible material expands to push a portion of the cooling fluid from the first volume portion into the closed fluid circuit; and ii) reciprocates as the compressible material compresses to pull the portion of the cooling fluid from the closed fluid circuit into the first volume portion, thereby maintaining the operating pressure.

10. The CDU according to claim 8, wherein, The first hollow piston is further fluid-driven by the actuator to compress the compressible material, thereby simultaneously restoring the compressible material in the third volume portion to the operating pressure.

11. The CDU according to claim 10, wherein, The second volume portion is fluidly connected to a driver fluid reservoir via a first opening in the cylinder, and wherein the driver fluid is pumped from the driver fluid reservoir into the second volume portion, thereby: i) driving the second hollow piston to inject the additional cooling fluid from the first volume portion into the closed fluid circuit; and ii) driving the first hollow piston to compress the compressible material until the pressure levels of the cooling fluid in the closed fluid circuit and the compressible material in the third volume portion return to the operating pressure.

12. The CDU according to claim 8, further comprising a limit switch disposed on the cylinder, wherein, The first volume portion is fluidly connected to a supplemental cooling fluid reservoir via a second opening in the cylinder, and wherein, in response to the limit switch detecting a minimum threshold volume level of the cooling fluid in the first volume portion, supplemental cooling fluid is pumped from the supplemental cooling fluid reservoir into the first volume portion until the volume levels of the cooling fluid and the supplemental cooling fluid in the first volume portion increase from the minimum threshold volume level to a predefined volume level.

13. The CDU according to claim 12, wherein, The supplemental cooling fluid pumped into the first volume portion drives the second hollow piston to refill the first volume portion with the supplemental cooling fluid and discharge a portion of the drive fluid from the second volume portion into a drive fluid reservoir, which is fluidly connected to the second volume portion via a first opening in the cylinder.

14. The CDU according to claim 8, wherein, The cooling fluid is a mixture of water and propylene glycol and additives, a dielectric fluid, or water; the drive fluid is propylene glycol, a hydraulic fluid, water, or a mixture of water and propylene glycol; the compressible material is a compressible spring, an elastomer component, or a compressible fluid; the operating pressure is in the range of 10 psi to 150 psi; the predefined pressure drop is 10% of the operating pressure; the predefined time period is 1 minute; the minimum threshold volume level is 20% of the internal volume; and the predefined volume level is 60% of the internal volume.

15. The CDU according to claim 8, wherein, The pressure regulator assembly functions as a combination of an energy accumulator and a cooling fluid reservoir.

16. A method of operating a pressure regulator assembly, comprising: A pressure regulator assembly guides the flow of cooling fluid in a closed fluid loop of a coolant distribution unit (CDU), the pressure regulator assembly comprising: a cylinder having an internal volume; and a first hollow piston and a second hollow piston slidably connected to the cylinder to divide the internal volume into a first volume portion having the cooling fluid, a second volume portion having a driving fluid, and a third volume portion having a compressible substance, wherein the first volume portion is fluidly connected to the closed fluid loop; The first hollow piston is reciprocated by the compressible material to maintain the operating pressure of the cooling fluid in the closed fluid circuit; and The second hollow piston is driven by the driver fluid in response to a predefined pressure drop of the cooling fluid in the closed fluid circuit during a predefined time period, to inject additional cooling fluid from the first volume portion into the closed fluid circuit, thereby restoring the pressure level to the operating pressure. Each of the cooling fluid and the driving fluid is an incompressible fluid.

17. The method according to claim 16, wherein, The reciprocating motion of the first hollow piston includes: As the compressible material expands, the first hollow piston slides to push a portion of the cooling fluid from the first volume portion into the closed fluid circuit; and The first hollow piston slides during compression of the compressible material to draw a portion of the cooling fluid from the closed fluid circuit into the first volume portion, thereby maintaining the operating pressure.

18. The method of claim 16, further comprising: The first hollow piston is fluidly driven by the actuator to simultaneously restore the compressible material in the third volume portion to the operating pressure.

19. The method of claim 16, wherein, The cooling fluid is a mixture of water and propylene glycol and additives, a dielectric fluid, or water; the drive fluid is propylene glycol, a hydraulic fluid, water, or a mixture of water and propylene glycol; the compressible material is a compressible spring, an elastomer component, or a compressible fluid; the operating pressure is in the range of 10 psi to 150 psi; the predefined pressure drop is 10% of the operating pressure; the predefined time period is 1 minute; the minimum threshold volume level is 20% of the internal volume; and the predefined volume level is 60% of the internal volume.

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