Novel heat pipe configuration

Abstract

1. A type of heat pipe having a condenser section in which a gaseous refrigerant is condensed to produce a liquid refrigerant, (a) at least one closed pipe; (i) a condenser section; (ii) a first evaporator section in fluid communication with the condenser section; (iii) at least one closed pipe including at least a second evaporator section in fluid communication with the condenser section; (b) a refrigerant contained in the heat pipe; (c) at least a first liquid flow path that directs a first portion of the liquid refrigerant condensed in the condenser section to the first evaporator section; and (d) at least a second liquid flow path directing a second portion of the liquid refrigerant condensed in the condenser section to the second evaporator section, the second evaporator section including a reservoir for holding liquid refrigerant in a location different from the first evaporator section.

Description

[Technical Field]

[0001] (cross reference) This application claims priority benefit of PCT / CN2020 / 121546, filed October 16, 2020, which is incorporated herein by reference in its entirety.

[0002] FIELD OF THE INVENTION The present invention relates to a novel heat pipe configuration and, more particularly, to a method and system utilizing the same. [Background technology]

[0003] As used herein, the term "heat pipe" means a heat transfer device containing a liquid heat transfer fluid in an evaporative section and a vapor working fluid in a condensing section, which uses the power of evaporation to move the vapor fluid from the evaporative section to the condensing section and returns the liquid working fluid to the evaporative section using little or no energy input.

[0004] One of the most common types of heat pipes is shown in Figure A and is commonly known as a gravity-return or thermosiphon heat pipe. This type of heat pipe relies at least in part on gravity to return a liquid working fluid from the condensing section to the evaporating section. As shown in Figure A, in a typical configuration, a heat pipe is a vertically oriented enclosed vessel with the evaporating section located at the bottom of the pipe and the condensing section located at the top of the pipe. The evaporating section contains the working fluid in liquid form, which absorbs heat from an item, object, or fluid to be cooled and thereby boils to form a working fluid vapor. Boiling of the working fluid in the evaporating section creates a pressure differential, sending the vapor to the condensing section. The vapor working fluid in the condensing section releases heat to a selected heat sink (e.g., ambient air), thereby condensing to form a liquid working fluid at or near the inner surface of the heat pipe. This liquid then returns under gravity to the evaporating section and joins with the liquid working fluid contained therein.

[0005] As previously mentioned, boiling increases the mass of the vapor in the evaporator section and the mass of the vapor decreases in the condenser section, creating a pressure differential that sends the vapor from the boiler section to the condenser section, thus creating a continuous heat transfer cycle that requires no energy input (other than the heat absorbed in the cooling operation) to transport the working fluid from the evaporator section to the condenser section.

[0006] In some applications, it is desirable to position the heat pipe horizontally or at an angle. When the heat pipe is positioned completely horizontally, it is commonly known as a capillary return heat pipe, or a wicking heat pipe, an example of which is shown in Figure B.

[0007] In an arrangement of the type shown in Figure B, heat is absorbed by the liquid working fluid in the evaporator section (shown on the left side of Figure B), causing the liquid to boil, thereby providing a pressure differential that moves the vapor to the condenser section as described above. However, rather than relying solely on gravity to return the condensed liquid working fluid, a wicking structure is provided adjacent the vessel wall that uses capillary action to return the flow of condensed working fluid from the condenser section to the evaporator section. While the capillary return heat pipe in Figure B is shown in a vertical position, it will be understood that the capillary return heat pipe can be oriented in virtually any orientation depending on the needs and the particular geometry and capillary forces required for a given application. Thus, as used herein, the term "capillary return" heat pipe includes heat pipes with capillary return forces regardless of the heat pipe's orientation.

[0008] Other heat pipe configurations that use little or no additional energy to return the working fluid condensate to the evaporative section include electrohydrodynamic heat pipes (which utilize electrokinetic forces), electroosmotic heat pipes, magnetohydrodynamic heat pipes (which utilize magnetic forces), osmotic heat pipes, and oscillating heat pipes.

[0009] As a result of the extremely high heat transfer coefficients of boiling and condensation, heat pipes are very effective heat conductors. Therefore, heat pipes are used in many applications, particularly for cooling electronic devices. One important application of heat pipe cooling is the removal of heat from multiple components, including, for example, microchips, mounted on a printed circuit board. For illustrative purposes, a vertically mounted printed circuit board (PCB) C1 has three components C2, C3, and C4 mounted thereon to be cooled. Components C2, C3, and C4 generate heat during operation and require heat removal therefrom by a gravity-return heat pipe C5 mounted in thermal communication with each of components C2, C3, and C4. Due to limitations associated with conventional heat pipes, it has traditionally been common to design circuit board configurations such that the heat-generating components are located adjacent to the lower portion of the heat pipe, since this is where the liquid phase of the working fluid primarily resides. Furthermore, conventional practice has not allowed for the size of the evaporator section to be substantially increased without sacrificing the size and performance of the condenser section, which is also critical to the overall performance of the heat pipe.

[0010] Applicants have also come to realize that by utilizing the novel heat pipe configuration as disclosed herein, improvements in PCB cooling performance and even the process of designing PCB layouts can be dramatically improved. Furthermore, the novel heat pipe configuration of the present invention can be advantageously used to cool many types of devices and systems other than PCBs and electronic systems. Summary of the Invention

[0011] The present invention relates to a heat pipe of the type having a condenser section in which a gaseous refrigerant is condensed to produce a liquid refrigerant, (a) at least one closed pipe; (i) a condenser section; (ii) a first evaporator section in fluid communication with the condenser section; (iii) at least one closed pipe including at least a second evaporator section in fluid communication with the condenser section; (b) a refrigerant contained in the heat pipe; (c) at least a first liquid flow path that directs a first portion of the liquid refrigerant condensed in the condenser section to the first evaporator section; (d) at least a second liquid flow path directing a second portion of the liquid refrigerant condensed in the condenser section to the second evaporator section, the second evaporator section including a reservoir for holding liquid refrigerant at a location different from the first evaporator section. For convenience, a heat pipe according to this paragraph will be referred to herein as heat pipe 1.

[0012] The present invention relates to a heat pipe of the type having a condenser section in which a gaseous refrigerant is condensed to produce a liquid refrigerant, (a) at least one closed pipe; (i) a condenser section; (ii) a first evaporator section in fluid communication with the condenser section; (iii) at least one closed pipe including at least a second evaporator section in fluid communication with the condenser section; (b) a refrigerant contained within the heat pipe, the heat pipe configured to return refrigerant liquid from the condenser section to the first and second evaporator sections at least partially using gravity; and (c) at least a first liquid flow path that directs a first portion of the liquid refrigerant condensed in the condenser section to the first evaporator section; (d) at least a second liquid flow path that directs a second portion of the liquid refrigerant condensed in the condenser section to the second evaporator section, wherein (i) the second liquid flow path is oriented obliquely with respect to the vertical and includes one or more obstacles that divert at least a portion of the liquid refrigerant from the condenser section toward the second evaporator, and the second evaporator section includes a reservoir that holds liquid refrigerant at a location different from the first evaporator section. For convenience, the heat pipe according to this paragraph will be referred to herein as heat pipe 2.

[0013] The present invention relates to a heat pipe of the type having a condenser section in which a gaseous refrigerant is condensed to produce a liquid refrigerant, (a) at least one closed pipe; (i) a condenser section that returns refrigerant liquid from the condenser section to the evaporator section, at least in part using gravity; (ii) a first evaporator section in fluid communication with the condenser section; (iii) a second evaporator section in fluid communication with the condenser section and intermediate the first evaporator section and the condenser section; (iv) at least one closed pipe in fluid communication with the condenser section and including at least a third evaporator section intermediate the first evaporator section and the condenser section; (b) a refrigerant contained within the heat pipe, the heat pipe configured to return refrigerant liquid from the condenser section to each of the first, second, and third evaporator sections at least partially using gravity; and (c) at least a first liquid flow path that directs a first portion of the liquid refrigerant condensed in the condenser section to the first evaporator section; (d) at least a second liquid flow path that directs a second portion of the liquid refrigerant condensed in the condenser section to the second evaporator section, (i) the second liquid flow path is oriented obliquely relative to the vertical and includes one or more obstacles that divert at least a portion of the liquid refrigerant from the condenser section toward the second evaporator, and the second evaporator section includes a reservoir that holds liquid refrigerant in a location different from the first evaporator section; and (e) at least a third liquid flow path directing a third portion of the liquid refrigerant condensed in the condenser section to the third evaporator section, (i) the third liquid flow path being oriented obliquely with respect to the vertical and including one or more obstacles that divert at least a portion of the liquid refrigerant from the condenser section toward the third evaporator section, the third evaporator section including a reservoir holding liquid refrigerant at a location different from the first evaporator section and different from the second evaporator section. For convenience, a heat pipe according to this paragraph will be referred to herein as heat pipe 3.

[0014] The present invention relates to a heat pipe of the type having a condenser section in which a gaseous refrigerant is condensed to produce a liquid refrigerant, (a) at least one closed pipe; (i) a condenser section; (ii) a first evaporator section in fluid communication with the condenser section; (iii) at least one closed pipe including at least a second evaporator section in fluid communication with the condenser section; (b) a refrigerant contained in the heat pipe; (c) at least a first liquid flow path that directs a first portion of the liquid refrigerant condensed in the condenser section to the first evaporator section; (d) at least a second liquid flow path directing a second portion of the liquid refrigerant condensed in the condenser section to the second evaporator section, the second evaporator section including a reservoir for holding liquid refrigerant at a location different from the first evaporator section, the second evaporator section having a total volume that is about 70% or less, or about 60% or less, or about 50% or less, or about 40% or less of the volume of the first evaporator section. For convenience, heat pipes according to this paragraph will be referred to herein as heat pipes 4.

[0015] The present invention relates to a printed circuit board (PCB), comprising: (a) at least a first heat-generating component mounted on a PCB at a first location; (b) at least a second heat-generating component mounted on the PCB at a second location different from the first location; (c) at least one heat pipe including a closed pipe; (i) a condenser section in thermal communication with a cooling fluid located outside the heat pipe; (ii) a first evaporator section including a first reservoir containing a liquid refrigerant in heat transfer contact with the first heat-generating component; (iii) a first liquid flow path that directs a first portion of the liquid refrigerant condensed in the condenser section to the reservoir in the first evaporator section; (iii) at least a second evaporator section including a second reservoir at a location along the heat pipe different from the first reservoir and containing a second portion of liquid refrigerant in heat transfer contact with the at least second heat-generating component; (iv) at least one heat pipe including at least a second liquid flow path that directs the second portion of the liquid refrigerant condensed in the condenser section to the reservoir in the second evaporator section. For convenience, the PCB according to this paragraph will be referred to herein as PCB1.

[0016] The present invention relates to a printed circuit board (PCB), comprising: (a) at least a first heat-generating component mounted on a PCB at a first location; (b) at least a second heat-generating component mounted on the PCB at a second location different from the first location; (c) A heat pipe including a closed pipe, (i) a condenser section in thermal communication with a cooling fluid located outside the heat pipe, where vapor refrigerant is condensed into liquid refrigerant; (ii) a first evaporator section including a first reservoir containing liquid refrigerant in heat transfer contact with the first heat-generating component, wherein gravity provides at least a portion of the force returning liquid refrigerant condensed within the condenser section to the first evaporator section; (iii) at least a first liquid flow path directing a first portion of the liquid refrigerant condensed in the condenser section to the reservoir in the first evaporator section; (iii) at least a second evaporator section including a second reservoir at a location along the heat pipe different from the first reservoir and containing a second portion of liquid refrigerant in heat transfer contact with the at least second heat-generating component, wherein gravity provides at least a portion of the force returning liquid refrigerant condensed in the condenser section to the second evaporator section; (iv) a heat pipe including at least a second liquid flow path that directs the second portion of the liquid refrigerant condensed in the condenser section to the reservoir in the second evaporator section. For convenience, the PCB according to this paragraph will be referred to herein as PCB2.

[0017] The present invention relates to a printed circuit board (PCB), comprising: (a) at least a first heat-generating component mounted on a PCB at a first location; (b) a second heat-generating component mounted on the PCB at a second location above the first location; and (c) at least a third heat-generating component mounted on the PCB at a third location above the first location; and (d) Heat pipes including closed pipes, (i) a condenser section in thermal communication with a cooling fluid located outside the heat pipe, where vapor refrigerant is condensed into liquid refrigerant; (ii) a first evaporator section located below the condenser section and including a first reservoir containing liquid refrigerant in heat transfer contact with the first heat-generating component, wherein gravity provides at least a portion of the force returning liquid refrigerant condensed within the condenser section to the first evaporator section; (iii) at least a first liquid flow path directing a first portion of the liquid refrigerant condensed in the condenser section to the reservoir in the first evaporator section; (iii) a second evaporator section including a second reservoir located along the heat pipe above the first reservoir and containing a second portion of liquid refrigerant in heat transfer contact with the second heat-generating component, wherein gravity provides at least a portion of the force returning liquid refrigerant condensed in the condenser section to the second evaporator section; (iv) at least a second liquid flow path directing the second portion of the liquid refrigerant condensed in the condenser section to the reservoir in the second evaporator section; (v) at least a third evaporator section including a third reservoir at a location along the heat pipe above the first reservoir and containing a third portion of liquid refrigerant in heat transfer contact with the third heat-generating component, wherein gravity provides at least a portion of the force returning liquid refrigerant condensed in the condenser section to the third evaporator section; (vi) a heat pipe including at least a third liquid flow path that directs the third portion of the liquid refrigerant condensed in the condenser section to the reservoir in the third evaporator section. For convenience, the PCB according to this paragraph will be referred to herein as PCB3.

[0018] The present invention relates to a printed circuit board (PCB), comprising: (a) at least a first heat-generating component mounted on a PCB at a first location; (b) at least a second heat-generating component mounted on the PCB at a second location different from the first location; (c) at least one heat pipe including a closed pipe; (i) a condenser section in thermal communication with a cooling fluid located outside the heat pipe; (ii) a first evaporator section including a first reservoir containing a liquid refrigerant in heat transfer contact with the first heat-generating component; (iii) a first liquid flow path that directs a first portion of the liquid refrigerant condensed in the condenser section to the reservoir in the first evaporator section; (iii) at least a second evaporator section including a second reservoir at a location along the heat pipe different from the first reservoir and containing a second portion of liquid refrigerant in heat transfer contact with the at least second heat-generating component, the second evaporator section having a total volume that is about 70% or less, or about 60% or less, or about 50% or less, or about 40% or less of the volume of the first evaporator section; (iv) at least one heat pipe including at least a second liquid flow path that directs the second portion of the liquid refrigerant condensed in the condenser section to the reservoir in the second evaporator section. For convenience, the PCB according to this paragraph will be referred to herein as PCB4.

[0019] The present invention is a method of transferring heat, comprising a heat pipe of the type having a condenser section in which a gaseous refrigerant is condensed to produce a liquid refrigerant, (a) A closed heat pipe, (i) a condenser section in heat transfer communication with a heat sink located external to the heat pipe; (ii) a first evaporator section in fluid communication with the condenser section, the first evaporator section including a first reservoir containing a liquid refrigerant; (iii) at least a second evaporator section in fluid communication with the condenser section, the second evaporator section including a second reservoir containing a liquid refrigerant; (iv) at least a first liquid flow path leading from the condenser section to the first reservoir; (v) providing a closed heat pipe including at least a second liquid flow path leading from said condenser section to said second reservoir; (b) cooling a first component or device by thermally contacting the liquid refrigerant in the first reservoir to produce a refrigerant vapor that travels to the condenser section; (c) cooling a second component or device by thermally contacting the liquid refrigerant in the second reservoir to produce a refrigerant vapor that travels to the condenser section; (d) condensing the refrigerant vapor in a condenser section to produce a condensed liquid refrigerant, returning a first portion of the condensed liquid refrigerant to the first reservoir via the first liquid flow path, and returning a second portion of the condensed liquid refrigerant to the second reservoir via the second liquid flow path. For convenience, the heat transfer method according to this paragraph will be referred to herein as Heat Transfer Method 1.

[0020] The present invention provides a method of transferring heat, comprising: (a) A closed heat pipe, (i) a condenser section in heat transfer communication with a heat sink located outside the heat pipe, in which the vapor refrigerant is condensed into a liquid refrigerant; (ii) a first evaporator section in fluid communication with the condenser section, the first evaporator section including a first reservoir containing a liquid refrigerant; (iii) a second evaporator section in fluid communication with the condenser section, the second evaporator section including a second reservoir containing a liquid refrigerant; (v) at least a first liquid flow path directing at least a portion of the condensed liquid refrigerant from the condenser section to the first reservoir, wherein gravity provides at least a portion of the force returning the liquid refrigerant condensed in the condenser section to the first evaporator section; (vi) providing a closed heat pipe including at least a second liquid flow path that directs at least a portion of the liquid refrigerant from the condenser section to the second reservoir, wherein gravity provides at least a portion of the force returning the liquid refrigerant condensed in the condenser section to the second evaporator section; (b) cooling a first component or device by thermally contacting the liquid refrigerant in the first reservoir to produce a refrigerant vapor that travels to the condenser section; (c) cooling at least a second component or device by thermally contacting the liquid refrigerant in the second reservoir to produce a refrigerant vapor that travels to the condenser section; (e) condensing the refrigerant vapor in the condenser section to produce the condensed liquid refrigerant. For convenience, the heat transfer method according to this paragraph will be referred to herein as Heat Transfer Method 2.

[0021] The present invention provides a method of transferring heat, comprising: (a) A closed heat pipe, (i) a condenser section in heat transfer communication with a heat sink located outside the heat pipe, in which the vapor refrigerant is condensed into a liquid refrigerant; (ii) a first evaporator section in fluid communication with the condenser section, the first evaporator section including a first reservoir containing a liquid refrigerant; (iii) a second evaporator section in fluid communication with the condenser section, the second evaporator section including a second reservoir containing a liquid refrigerant; (iv) at least a third evaporator section in fluid communication with the condenser section, the third evaporator section including a third reservoir containing a liquid refrigerant; (v) at least a first liquid flow path directing at least a portion of the condensed liquid refrigerant from the condenser section to the first reservoir, wherein gravity provides at least a portion of the force returning the liquid refrigerant condensed in the condenser section to the first evaporator section; (vi) at least a second liquid flow path directing at least a portion of the liquid refrigerant from the condenser section to the second reservoir, wherein gravity provides at least a portion of the force returning the liquid refrigerant condensed in the condenser section to the second evaporator section; (vii) providing a closed heat pipe including at least a third liquid flow path directing liquid refrigerant from the condenser section to the third reservoir, wherein gravity provides at least a portion of the force returning liquid refrigerant condensed in the condenser section to the third evaporator section; (b) cooling a first component or device by thermally contacting the liquid refrigerant in the first reservoir to produce a refrigerant vapor that travels to the condenser section; (c) cooling at least a second component or device by thermally contacting the liquid refrigerant in the second reservoir to produce a refrigerant vapor that travels to the condenser section; (d) cooling at least a third component or device by thermally contacting the liquid refrigerant in the third reservoir to produce a refrigerant vapor that travels to the condenser section; (e) condensing the refrigerant vapor in the condenser section to produce the condensed liquid refrigerant. For convenience, the heat transfer method according to this paragraph will be referred to herein as Heat Transfer Method 3.

[0022] The present invention is a method of transferring heat, comprising a heat pipe of the type having a condenser section in which a gaseous refrigerant is condensed to produce a liquid refrigerant, (a) A closed heat pipe, (i) a condenser section in heat transfer communication with a heat sink located external to the heat pipe; (ii) a first evaporator section in fluid communication with the condenser section, the first evaporator section including a first reservoir containing a liquid refrigerant; (iii) at least a second evaporator section in fluid communication with the condenser section and including a second reservoir containing a liquid refrigerant, the second evaporator section having a total volume that is about 70% or less, or about 60% or less, or about 50% or less, or about 40% or less of the volume of the first evaporator section; (iv) at least a first liquid flow path leading from the condenser section to the first reservoir; (v) providing a closed heat pipe including at least a second liquid flow path leading from said condenser section to said second reservoir; (b) cooling a first component or device by thermally contacting the liquid refrigerant in the first reservoir to produce a refrigerant vapor that travels to the condenser section; (c) cooling a second component or device by thermally contacting the liquid refrigerant in the second reservoir to produce a refrigerant vapor that travels to the condenser section; (d) condensing the refrigerant vapor in a condenser section to produce a condensed liquid refrigerant, returning a first portion of the condensed liquid refrigerant to the first reservoir via the first liquid flow path, and returning a second portion of the condensed liquid refrigerant to the second reservoir via the second liquid flow path. For convenience, the heat transfer method according to this paragraph will be referred to herein as Heat Transfer Method 4. [Brief explanation of the drawings]

[0023] [Figure A]FIG. 1 is a schematic diagram of a gravity return heat pipe. [Figure B] FIG. 1 is a schematic diagram of a capillary return heat pipe. [Figure C] FIG. 1 is a schematic diagram of a printed circuit board housing three heat-generating components. [Figure 1] 1 is a schematic diagram of a heat pipe according to one embodiment of the present invention; [Figure 1A] 1 is a schematic diagram of a cross section of a heat pipe used in Example 1. FIG. [Figure 1B] 1 is a schematic diagram of a cross section of a heat pipe used in Example 1. FIG. [Figure C1] 1 is a schematic diagram of a heat pipe representing a conventional heat pipe. [Figure C2] FIG. 2 is a schematic diagram of a cross section of a heat pipe used in Comparative Example 1. [Figure C3] FIG. 10 is a schematic diagram of a cross section of a heat pipe used in Comparative Example 2. [Figure C4] FIG. 10 is a schematic diagram of a cross section of a heat pipe used in Comparative Example 3. [Figure 2] 1 is a schematic diagram of a heat pipe according to one embodiment of the present invention; [Figure 2A] FIG. 2 is a schematic diagram of a heat pipe according to one embodiment of the present invention, the performance of which is described in Example 2A. [Figure 2B] FIG. 1 is a schematic diagram of a heat pipe according to one embodiment of the present invention, the performance of which is described in Example 2B. [Figure 3A] 1 is a schematic diagram of a heat pipe according to an embodiment of the present invention; [Figure 3B] 1 is a schematic diagram of a heat pipe according to an embodiment of the present invention; [Figure 3C] 1 is a schematic diagram of a heat pipe according to an embodiment of the present invention; [Figure 3D] 1 is a schematic diagram of a heat pipe according to an embodiment of the present invention; [Figure 3E] 1 is a schematic diagram of a heat pipe according to an embodiment of the present invention; [Figure 3F] 1 is a schematic diagram of a heat pipe according to an embodiment of the present invention; [Figure 4] 1 is a photograph of a heat pipe according to an embodiment of the present invention and a heat pipe not within the scope of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0024] Applicants have unexpectedly discovered that by using the heat pipes, devices, systems and / or methods described herein, the above needs and advantages, among others, can be achieved and / or cooling efficiency and effectiveness can be achieved at low cost.

[0025] heat pipe The present invention includes a heat pipe that provides superior thermal performance and, in preferred embodiments, the ability to efficiently and effectively cool at least two heat sources located at different locations. By way of example, see FIG. 1 herein, which illustrates a schematic cross-section of a heat pipe, generally designated 10. While heat pipe 10 is shown schematically as having a rectangular cross-section, those skilled in the art will recognize that a wide variety of internal and external shapes and dimensions may be used consistent with the teachings herein, and that all such shapes and dimensions are within the scope of the present invention.

[0026] The heat pipe 10 preferably includes a containment area bounded by a pipe wall 11 including an outer pipe wall surface 11A and an inner pipe wall surface 11B. The heat pipe includes a first evaporator section 12A located at one end of the heat pipe and a condenser section 13 located at the other end of the heat pipe. Although the evaporator section 12A is shown as being at one end of the heat pipe and the condenser section is shown as being at the other end of the heat pipe, it will be understood that in accordance with the present invention, these sections need not be located at either end of the heat pipe.

[0027] The heat pipe 10 includes at least a second evaporator section 12B located intermediate the condenser section and the first evaporator section. Again, those skilled in the art will understand that while the heat pipe 10 shown in FIG. 1 is shown as having substantially straight sidewalls, and thus the evaporator section 12B is located above the first evaporator section 12A and below the condenser section 13, this arrangement is not necessary. In the configuration shown in FIG. 1, the top of the first evaporator section 12A is represented by a horizontal line 30 located at approximately 30 volume percent of the heat pipe, although those skilled in the art will understand that this location is for illustrative purposes and is not necessarily limiting. Furthermore, line 30 represents the approximate liquid level within the heat pipe when the heat pipe is not operating, which is referred to herein as the charge level, although it will be understood that during operation, the liquid level may not correspond to this location. During operation, heat is transferred from a first heat source (heater 1) through the pipe wall 11 into a reservoir of liquid refrigerant in the first evaporator section 12A to produce refrigerant vapor, shown in FIG. 1 as refrigerant bubbles 21, which flow generally upward toward the condenser section 13.

[0028] In the condenser section 13, the outer surface of the heat pipe is exposed to the relatively low temperature of a heat sink (e.g., ambient air blown across the top of the heat pipe as shown schematically in FIG. 1 ), which cools and condenses the refrigerant vapor that contacts the inner surface 11B of the heat pipe wall 11 in the condenser section 13. A first portion of the condensed refrigerant liquid follows a first flow path, generally designated, for example, as path 14A, back to a reservoir contained in the first evaporator section 12A. Those skilled in the art will appreciate that in many heat pipe configurations according to the present invention, multiple flow paths leading from the condenser section to the evaporator section 12A exist, and flow path 14A is shown as only one general flow path that may exist. Other possible flow paths may include the general path designated as 14B. Thus, while it is contemplated that at least a first portion of the refrigerant liquid may take numerous different flow paths upon returning to the first evaporator section, the first flow path may simply comprise a series of droplets falling from the condenser section 13 to the first evaporator section 12A under the influence of gravity.

[0029] An important and critical aspect of the present invention is the provision of a second flow path, generally designated, for example, as item 15, for directing or guiding at least a second portion of the refrigerant liquid condensed in the condenser section 13 to a reservoir contained in the evaporator section 12B. As those skilled in the art will appreciate, a number of features can be included in the heat pipe to capture and route a portion of the condensed liquid from the condenser section to the reservoir. One such feature can include, for example, a series of angled platforms, plates, tiles, etc. 16 positioned within the general flow path through which the liquid refrigerant falls from the condenser section 13 under the influence of gravity. These platforms or plates are positioned and angled to direct such droplets toward the interior wall of the heat pipe and into the reservoir contained in the second evaporator section 12B. In preferred embodiments, small gaps are preferably included between adjacent platforms, plates, etc. to allow for the upward passage of some refrigerant vapor. Additionally, the lower edge of each plate is preferably aligned to overlap the upper edge of the next flow plate, platform, etc. in the direction of liquid flow. Given the teachings contained herein, one skilled in the art will be able to select both the extent of vertical separation and the extent of vertical overlap for a particular application to achieve the desired flow of refrigerant into the reservoir of the evaporator section 12B and the desired level of refrigerant vapor flow. In this manner, a desired supply of liquid refrigerant is provided midway between the first evaporator section and the condenser section, and in a preferred embodiment, the second evaporator section is located in close proximity to the heat source to be cooled, e.g., heater 2 in FIG. 1. Therefore, such a second heat source provides superior cooling because it is cooled by refrigerant phase-change heat transfer, which is much more effective and efficient than heat transfer from the second heat source that can occur in conventional heat pipe configurations.

[0030] 1 discloses a gravity-driven heat pipe, the present invention can be readily adapted for use with heat pipes having other forces or forces that drive the return of condensed liquid in the general direction of the first evaporator section. Accordingly, the present invention includes heat pipes having any one or combination of the liquid refrigerant driving forces described above, with capillary return heat pipes and gravity / capillary return heat pipes being particularly preferred.

[0031] FIG. 2 shows a heat pipe 10 having a typical honeycomb grid pattern of hexagonal cells to allow free upward flow of refrigerant vapor from the bottom region of the heat pipe, which generally houses the first evaporator section 12A, to the condenser section 13. The top of the first evaporator section 12A is generally represented by a horizontal line located at approximately 30 volume percent of the heat pipe. During operation, heat is transferred from a heat source (not shown) through the pipe wall into a reservoir of liquid refrigerant within the first evaporator section 12A. Refrigerant vapor is generated and flows upward through open vertical and diagonal channels within the heat pipe, i.e., channels not blocked by one or more tiles 16, to the condenser section 13. In the condenser section 13, the outer surface of the heat pipe is exposed to the relatively low temperature of a heat sink (e.g., ambient air), which cools and condenses the refrigerant vapor that comes into contact with the inner surface of the heat pipe wall in the condenser section 13. A first portion of the condensed refrigerant liquid follows a first flow path, such as 14A, back to a reservoir contained in the first evaporator section 12A. As previously mentioned, the liquid refrigerant may follow alternative and / or additional flow paths, such as flow paths 14B and 14C, on its return to the first evaporator section 12A. Thus, while it is contemplated that this first portion of the refrigerant liquid may take many different flow paths on its return to the first evaporator section 12A, the first flow path may simply comprise a series of droplets falling under the influence of gravity from the condenser section 13 to the first evaporator section 12A through one or more open channels, such as the outlet between columns 5 and 6 and the bottom between columns 4 and 5, as well as many other potential channels, including, but not limited to, those represented by flow paths 14B and 14C.

[0032] An important and critical aspect of the present invention is the provision of at least a second flow path, generally indicated as item 15 in FIG. 2, for directing at least a second portion of the refrigerant liquid condensed in the condenser section 13 to flow into a reservoir 12B' contained in the evaporator section 12B. As will be appreciated by those skilled in the art, a number of structures can be included in the heat pipe to capture and route a portion of the condensed liquid from the condenser section to the reservoir. One such structure can include, for example, a series of angled platforms, plates, tiles, etc. 16 positioned within the general flow path through which the liquid refrigerant falls from the condenser section 13, generally along flow path 14, under the influence of gravity. These platforms or plates are preferably positioned, angled, or configured to direct such droplets toward the interior wall of the heat pipe and into the reservoir 12B' contained in the second evaporator section 12B. In preferred embodiments, small vertical gaps are included between the platforms or plates to allow some upward passage of refrigerant vapor, and small vertical overlaps are included between adjacent platforms or plates to help direct the liquid refrigerant along the desired flow path into the reservoir of the evaporator section 12B. In this manner, a desired supply of liquid refrigerant is provided to at least one point intermediate the first evaporator section and the condenser section. In preferred embodiments, a second heat source (not shown) can be located near this second evaporator section. This provides superior cooling performance for the heat pipe of the present invention, particularly when a second heat source is present, because it is cooled by refrigerant phase-change heat transfer, which is much more effective and efficient than heat transfer that can occur in conventional heat pipe configurations.

[0033] Thus, in preferred embodiments of the present heat pipes, including heat pipes 1-4, the interior of the heat pipe is not completely homogenous. Instead, it comprises a honeycomb grid that includes a series of modifications to the grid structure, such as one or more angled tiles, plates, platforms, or similar obstacles formed in the grid structure, that tend to direct at least a portion of the condensed refrigerant liquid along flow paths that lead to the second evaporator section. For example, such exemplary structures are arranged to form flow paths or channels that lead a portion of the condensed liquid refrigerant to the second evaporator section. In particular, the general honeycomb pattern disclosed in FIG. 2 includes six columns of hexagonal cells or islands 20 around which liquid flows generally downward, with spaces between the cell columns generally allowing downward flow of liquid and upward flow of vapor. For example, liquid flowing from above rows 5 and 6 can flow to the bottom of the heat pipe to reach the first evaporator section. If all the rows and spaces were substantially the same as in a conventional heat pipe, all of the liquid would flow in this manner to the first evaporator section at the bottom of the heat pipe. However, according to an embodiment of the present invention, some of the rows are interrupted by overlapping angled tiles or plates incorporated into the honeycomb structure. For example, a portion of the liquid refrigerant flowing down between columns 4 and 5 in FIG. 2 will flow through the 9th row of cells. 番目 The refrigerant encounters a row of angled tiles or plates, thus diverting at least a portion of the refrigerant liquid toward the side of the heat pipe above the first evaporator section and into a second reservoir positioned to hold a selected amount of liquid refrigerant in heat transfer contact with the inner surface of the heat pipe, preferably adjacent the second heat source.

[0034] Alternative heat pipe configurations having different shapes and sizes for the cells or islands, vapor channels, tiles or platforms, and reservoirs are shown in each of Figures 3A-3E.

[0035] In FIG. 3A, the rows of hexagonal cells 20 are arranged in what is known as a rectangular grid arrangement, with the cells in each row aligned vertically and the cells in each column aligned horizontally, and include a series of angled plates or tiles 16 for directing a portion of the condensed refrigerant fluid to a reservoir in the intermediate evaporator 12B.

[0036] In FIG. 3B, rows of hexagonal cells 20 with a series of angled plates or tiles 16 arranged in what is known as a honeycomb grid arrangement are used to direct a portion of the condensed refrigerant fluid to a reservoir in the intermediate evaporator 12B.

[0037] In FIG. 3C, rows of circular cells 20 with a series of angled plates or tiles 16 are used to direct a portion of the condensed refrigerant fluid to a reservoir within the inter-evaporator 12B.

[0038] In FIG. 3D, rows of square cells 20 with a series of angled plates or tiles 16 are used to direct a portion of the condensed refrigerant fluid to a reservoir in the inter-evaporator 12B.

[0039] In Figure 3E, columns of angled, overlapping rectangular cells 20, some of which are cut out, are used to form flow paths that direct condensed refrigerant fluid to several intermediate reservoirs in the intermediate evaporator section, as described below in connection with Figure 3F. As seen in this embodiment, the angled rectangular cells provide ledges, tiles, plates, etc. to provide the necessary intermediate refrigerant flow paths, as described in more detail in connection with Figure 3F.

[0040] Figure 3F provides an enlarged view of the top of the heat pipe shown in Figure 3E, showing five columns of angled rectangular cells 20, labeled from left to right as columns 20A through 20E, used to create flow paths that direct condensed refrigerant fluid to several intermediate reservoirs within the intermediate evaporator section. As can be seen, rows 20A and 20E are on the left and right sides of the heat pipe, and each of these rectangular cells is partially cut away along its left and right edges, respectively. During operation, most of the refrigerant condensed at the top of the heat pipe between rows 20A and 20B, as well as some of the refrigerant condensed above rows 20B and 20C, tends to follow flow path 15A to the reservoir of evaporator 12B. Similarly, most of the refrigerant condensed at the top of the heat pipes between rows 20B and 20C, as well as some of the refrigerant condensed above rows 20C and 20D, will tend to follow flow path 15B to the reservoir of evaporator 12C. In view of this description, those skilled in the art will appreciate that the configuration of Figure 3E provides a series of multiple flow paths leading to a series of intermediate evaporative sections 12B-12J.

[0041] The tiles and plates used in the heat pipes of the present invention, including each of Heat Pipes 1-4 and the heat pipes contained in each of PCBs 1-4 and Heat Transfer Methods 1-4, may be angled over a wide variety of angles, but in preferred embodiments the tiles are angled from about 10° to about 70° relative to a plane perpendicular to the general direction of flow of refrigerant liquid from the condenser section to the first evaporator section, and relative to the horizontal in many applications including gravity return heat pipes.

[0042] The present invention includes tiles and plates used in the heat pipes of the present invention, included in each of Heat Pipes 1-4, and PCBs 1-3 and Heat Transfer Methods 1-4, at an angle of about 20° to about 50° relative to a plane perpendicular to the general direction of flow of refrigerant liquid from the condenser section to the first evaporator section, and relative to the horizontal in many applications, including gravity return heat pipes. In a preferred embodiment of Heat Pipe 4, Heat Transfer Method 4, and PCB 4, the second evaporator section does not include any flow passages or channels leading to another evaporator section, as shown in FIG. 2B.

[0043] While it is contemplated that the fill factor used in the heat pipes of the present invention, including each of Heat Pipes 1-4 and the heat pipes contained in each of PCBs 1-4 and Heat Transfer Methods 1-4, can vary widely, in preferred embodiments the fill factor is from about 20% to about 90% by volume.

[0044] The fill factor used in the heat pipes of the present invention, including each of Heat Pipes 1-4 and the heat pipes contained in each of PCBs 1-4 and Heat Transfer Methods 1-4, ranges from about 20% to about 60% by volume in preferred embodiments.

[0045] Devices and Systems The present invention includes devices and systems that include PCB1 to PCB4, each of which requires cooling during operation.

[0046] The present invention includes telecommunications devices and systems that include printed circuit boards, including each of PCB1 through PCB4.

[0047] The present invention includes telecommunications devices and systems comprising printed circuit boards, including PCB1 to PCB4, each including a 5G chip.

[0048] The present invention includes a 5G chip cooled by a heat pipe of the present invention comprising each of heat pipes 1 to 4.

[0049] The present invention includes a system or device comprising a heat pipe of the present invention, including each of heat pipes 1 to 4.

[0050] method The present invention includes methods for cooling a device or system, or a component of a device or system, using the methods of the present invention, including each of Heat Transfer Method 1 through Heat Transfer Method 4.

[0051] The present invention includes methods of cooling an electrical communication device or system using the methods of the present invention, including each of Heat Transfer Method 1 through Heat Transfer Method 4.

[0052] The present invention includes methods of cooling an electrical communication device or system using the methods of the present invention, including each of Heat Transfer Method 1 through Heat Transfer Method 4.

[0053] The present invention includes methods for cooling telecommunications devices and systems, including 5G chips, using the methods of the present invention, including each of Heat Transfer Method 1 to Heat Transfer Method 4.

[0054] The present invention includes a method of cooling at least a portion of a printed circuit board, the method comprising contacting at least a portion of the printed circuit board with a heat pipe of the present invention, including each of heat pipes 1 to 4.

[0055] The present invention includes a method of cooling at least a portion of a printed circuit board, including a 5G chip, by contacting the 5G chip with a heat pipe of the present invention, including each of heat pipes 1 to 5. [Example]

[0056] Comparative Examples 1A to 1F A heat pipe generally corresponding to Figure C1 herein was formed from two aluminum plates, except that a total of three heater bands were used instead of the two heaters shown in Figure C1. Each of the three heaters had a power of 13.33 watts, for a total power of 40 watts. This example configuration simulates the situation that exists when, for example, there are three components to be cooled, arranged vertically at these locations on a printed circuit board. Thermocouples were placed on the heat pipe wall at the following locations measured vertically from the bottom of the heat pipe: 70 mm, 150 mm, 210 mm, 270 mm, and 330 mm.

[0057] Six different heat pipe filling rates were tested using the heat pipe configuration described in the Examples, as shown in Table C1 below.

[0058] As shown in Figure C2, the cross section of the heat pipe shows that the channels between the two aluminum plates have a substantially uniform honeycomb configuration. As a result, during operation, the working fluid R-1233zd(E) contained in the reservoir of the evaporator section is heated, vaporizes, and flows generally upward through the heat pipe to the condenser section. Once the working fluid is condensed in the condenser section, the working fluid simply flows generally downward back to the evaporator section containing the liquid working fluid. The heat pipe was operated at a room temperature of approximately 23.7°C. The temperatures measured at equilibrium are reported in Table C1 below.

[0059] [Table 1] As can be seen from the data reported in Table C1, the lowest average temperature during operation was achieved at a fill factor of 60% (Example C1C), and the smallest temperature difference was achieved at a fill factor of 80% (Example C1B).

[0060] Examples 1A to 1F A heat pipe was formed having the same overall dimensions and the same heater and thermocouple as described in Comparative Example 1, except that the cross section of the heat pipe was generally as described in connection with Figure 1, and specifically as shown in Figure 1A. Six different heat pipe filling rates were tested using the heat pipe configuration described in the Examples, as shown in Table 1 below.

[0061] 1A, the cross section of the heat pipe shows that the channels between the two aluminum plates have a honeycomb configuration that captures and routes a portion of the condensed liquid from the condenser section to a reservoir in each of the evaporator sections 12B-12E. As the refrigerant condenses in the condenser section, a portion of the condensed working fluid liquid flows downward toward each of the evaporator sections 12B-12E.

[0062] The heat pipe was operated at a room temperature of about 23.7° C. The temperatures measured at equilibrium along with the results from Comparative Example 1 are reported in Table 1 below.

[0063] [Table 2] * The vertical positions at 70 mm, 150 mm, 210 mm, 270 mm and 330 mm are designated in the table as positions 1 to 5, respectively.

[0064] As can be seen from the results reported in Table 1 above, configurations according to described embodiments of the present invention produced lower average temperatures and smaller temperature differentials for all fill factors tested. Furthermore, the best performance from conventional heat pipes occurred at an 80% fill factor, as measured by average temperature, and a 60% fill factor, as measured by temperature differential. In contrast, the best performance from the heat pipes of the present invention occurred at a much lower fill factor, i.e., a minimum average temperature and minimum temperature differential of 50%. Thus, this example demonstrates that the heat pipes of the present invention offer at least three important advantages: (1) lower average temperatures, which are indicative of cooling effectiveness; (2) smaller temperature differentials, which help avoid unnecessary extreme temperatures within the heat pipe, thus improving operability and equipment life; and (3) reduced working fluid costs by reducing the fill factor to achieve better performance.

[0065] Comparative Example 2 A heat pipe generally corresponding to Figure C1 herein was formed from two aluminum plates, except that a total of five heater bands were used instead of the two heaters shown in Figure C1.

[0066] The heat pipe was approximately 935 mm from bottom to top, with five heater bands positioned approximately as shown in Figure C3. Each heater had a power of 11 watts, for a total power of 55 watts to the heat pipe. Thermocouples were provided on the heat pipe wall at the following locations measured vertically from the bottom of the heat pipe: 100 mm, 460 mm, 600 mm, 740 mm, and 880 mm. This example configuration simulates the situation that would exist if, for example, there were five components to be cooled and they were vertically positioned at these locations on a printed circuit board. The fill factor of the working fluid R1233zd(E) was set to approximately 90%, considering that heat input would essentially occur along the entire length of the heat pipe. This liquid level is approximately indicated by line 12A when all heaters are off.

[0067] As shown in Figure C3, the cross section of the heat pipe shows that the channels between the two aluminum plates have a substantially uniform honeycomb configuration. As a result, during operation, the working fluid R-1233zd(E) contained in the reservoir of the evaporator section is heated, vaporizes, and flows generally upward through the heat pipe to the condenser section. Once the working fluid is condensed in the condenser section, the working fluid simply flows generally downward back to the evaporator section containing the liquid working fluid. The heat pipe was operated at a room temperature of approximately 26.6°C. The temperatures measured at equilibrium are reported in Table C2 below.

[0068] [Table 3]

[0069] This example shows that the temperature of the heat pipe at the 100mm position was 47.4°C, and the difference between the 100mm and 460mm positions was 3.9°C, which was the maximum measured temperature difference of the heat pipe during operation.

[0070] Example 2 A heat pipe was formed having the same overall dimensions and the same heater and thermocouple as those described in Comparative Example 2, except that the cross section of the heat pipe was generally as described in connection with FIG. 1 and specifically as shown in FIG. 1B. Because a more efficient and effective configuration of the heat pipe of the present invention was used, testing was performed at a 40% fill factor, less than half the fill factor used in Comparative Example 2. As seen in FIG. 1B, the structure between the two aluminum plates captures and routes a portion of the condensed liquid from the condenser section to the reservoirs of each of the evaporator sections 12B-12E. As the refrigerant condenses in the condenser section, a portion of the condensed working fluid liquid flows downward toward each of the evaporator sections 12B-12E.

[0071] The heat pipe was operated at a room temperature of about 26.6° C. The temperatures measured at equilibrium along with the results of Comparative Example 2 are shown in Table 2 below.

[0072] [Table 4]

[0073] As can be seen from the results reported in Table 2 above, the configuration in accordance with the present invention produced lower temperatures at each location along the heat pipe, indicating that under comparable conditions, more cooling is provided by the heat pipe in accordance with the present invention, even at a fill factor less than half that used in Comparative Example 2. Furthermore, the temperature difference between sections of the heat pipe was lower for certain sections of the heat pipe compared to the conventional heat pipe configuration. For example, the temperature only increased 3.1°C from the 100 mm position to the 460 mm position, while the temperature increased 3.9°C for the conventional heat pipe configuration, indicating a superior level of cooling efficiency between these locations. This example demonstrates the same advantages as discussed above in connection with Example 1.

[0074] Comparative example 3A A heat pipe generally corresponding to Figure C1 herein, and specifically as shown in Figure C4, is formed from two aluminum plates and has two heat sources of the same size and heat output, with Heater 1 located adjacent to one side of the bottom half of the heat pipe and Heater 2 located adjacent to the same side but along the top half of the heat pipe.

[0075] Separate thermocouples were provided at each of seven locations on the heat pipe wall, spaced approximately equally from the bottom to the top of the heat pipe. The working fluid in the heat pipe was R1233zd(E), and the amount of R1233zd(E) charge required to provide best performance in the heat pipe was determined to be 63.1 grams.

[0076] Additionally, a 1 mm aluminum plate was tested under the same operating conditions as used for the heat pipe. The results of these two tests are presented below.

[0077] [Table 5]

[0078] Examples 2A and 2B Two heat pipes were fabricated having the same overall dimensions and the same heaters and thermocouples as those described in Comparative Example 3, except that the cross-sections of the heat pipes were generally as described in connection with FIG. 1 and specifically as shown in FIGS. 2A and 2B. In particular, the heat pipe shown in FIG. 2A had nine evaporator sections and associated flow channels, as shown, in accordance with the present invention. The heat pipe of FIG. 2B had an upper section essentially configured as the upper section of the heat pipe of FIG. 2A; i.e., the top five evaporator sections and associated flow channels of each of the heat pipes of FIGS. 2A and 2B were substantially the same size and configuration as shown. However, the bottom four flow channels of the heat pipe of FIG. 2A were replaced by a single evaporator section in accordance with the heat pipe of FIG. 2B. Importantly, this single lower evaporator section was sized to have a volume less than half the total volume of the four lower evaporator sections of the heat pipe of FIG. 2A. The optimized filling and performance for the heat pipes of FIGS. 2A and 2B, along with the results repeated for Comparative Example 3, are reported in the table below.

[0079] [Table 6]

[0080] As can be seen from the above results, the heat pipe of FIG. 2A performed best, with the lowest average temperature difference at 33.4°C and the lowest maximum temperature rise at only 5.4°C. This performance is unexpectedly superior to that of the 1 mm aluminum plate and comparative heat pipes, as shown in FIG. C4, the subject of Comparative Example C3. Furthermore, the heat pipe of FIG. 2B also performed unexpectedly better than the heat pipe of FIG. C4, with an average temperature difference of 34°C and a maximum temperature difference of 8°C. Both of these values ​​are unexpectedly superior to that of the heat pipe of FIG. C4. Additionally, while performance as measured by temperature difference for the embodiment of the type represented by FIG. 2B is not as good as that of FIG. 2A, performance is nevertheless unexpectedly good, especially when considered in light of the substantially less optimal fill for the embodiment of FIG. 2B compared to all of the heat pipes in the table above. This heat pipe of the present invention of the type shown in FIG. 2B has the ability to achieve excellent heat transfer performance at a relatively low cost due to the reduced fill required to achieve such excellent heat transfer performance.

Claims

1. 1. A type of heat pipe having a condenser section in which a gaseous refrigerant is condensed to produce a liquid refrigerant, (a) at least one closed pipe; (i) a condenser section; (ii) a first evaporator section in fluid communication with the condenser section; (iii) at least one closed pipe including at least a second evaporator section in fluid communication with the condenser section; (b) a refrigerant contained in the heat pipe; (c) at least a first liquid flow path that directs a first portion of the liquid refrigerant condensed in the condenser section to the first evaporator section; (d) at least a second liquid flow path directing a second portion of the liquid refrigerant condensed in the condenser section to the second evaporator section, the second evaporator section including a reservoir for holding liquid refrigerant in a location different from the first evaporator section; the heat pipe is configured to return refrigerant liquid from the condenser section to the first and second evaporator sections at least partially using gravity; the second liquid flow path comprising a plurality of obstacles within the heat pipe, the plurality of obstacles being oriented obliquely relative to a vertical direction and diverting at least a portion of the liquid refrigerant from the condenser section toward the second evaporator section; the obstacles are arranged such that, in the direction of liquid refrigerant flow toward the second evaporator section, lower ends of the obstacles overlap upper ends of adjacent obstacles, but adjacent obstacles are separated by gaps to allow upward passage of refrigerant vapor; Heat pipe.

2. 2. The heat pipe of claim 1, further comprising at least a third liquid flow path that directs a third portion of the liquid refrigerant condensed in the condenser section to a third evaporator section, wherein (i) the third liquid flow path is oriented obliquely with respect to a vertical direction and includes one or more obstacles that divert at least a portion of the liquid refrigerant from the condenser section toward the third evaporator section, and (ii) the third evaporator section includes a reservoir that holds liquid refrigerant at a location different from the first evaporator section and different from the second evaporator section.

3. 3. The heat pipe of claim 2, wherein at least one of the second evaporator section and / or the third evaporator section has a total volume that is less than or equal to about 0.7 times (about 70%) the volume of the first evaporator section.

4. 4. The heat pipe according to claim 1, wherein the liquid refrigerant consists essentially of R-1233zd(E).

5. 1. A printed circuit board (PCB), comprising: (a) at least a first heat-generating component mounted on the PCB at a first location; (b) at least a second heat-generating component mounted on the PCB at a second location different from the first location; (c) at least one heat pipe according to any one of claims 1 to 4. A printed circuit board comprising:

6. 6. The telecommunications device including the PCB of claim 5, wherein at least one of the first or second heat-generating components is a 5G chip on the PCB.

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