Multi-stage cooling heat pipe

Abstract

The present invention provides a heat pipe for cooling electronic components of a printed circuit board. The heat pipe includes a conduit having an inner diameter surface defining an inner hole, and the conduit has a first end and a second end along the inner hole. The heat pipe also includes an adsorbent material coated on the inner diameter surface of the conduit, a first liquid contained in the inner hole, and a second liquid adsorbed by the adsorbent material. The second boiling temperature of the second liquid is higher than the first boiling temperature of the first liquid. In response to the conduit receiving heat from the electronic component and the first liquid reaching the first boiling temperature, the first liquid evaporates into a first vapor. In response to the second liquid reaching the second boiling temperature, the second liquid is desorbed from the adsorbent material and evaporates into a second vapor.

Description

Technical Field

[0001] The present invention relates generally to electronic device cooling and, more particularly, to a heat pipe having multiple liquids and associated boiling temperatures that differ from one another to achieve multi-stage cooling. Background Art

[0002] Whenever current flows through an electronic device, it generates heat. The amount of heat generated depends on the power, device characteristics, and circuit design. The resistance of the processor, driver circuits, power circuits, and memory contributes to some heat and power losses. To avoid malfunctions or circuit failures, electronic devices must operate and remain within safe temperature ranges. While some circuits can operate without additional cooling, others include mechanisms to dissipate heat.

[0003] Existing heat pipes for electronic devices include an elongated conduit containing a single liquid. The conduit has a first end that transfers heat from the electronic component to the liquid so that when the temperature of the liquid reaches its boiling temperature, the liquid evaporates into steam. The heat pipe also includes a second end that transfers heat from the steam to the surrounding environment for condensing the steam into liquid when the temperature of the steam drops below the boiling temperature. The heat pipe also includes a wicking material that interconnects the first end and the second end so that the condensed liquid returns from the second end to the first end. Under dry conditions, when all the liquid evaporates into steam, the steam will not move to the second end to cool, and condensate will not form and return to the first end, so that the cooling capacity of the heat pipe is adversely affected.

[0004] Therefore, while existing heat pipes achieve their intended purpose, a need exists for a new and improved heat pipe for electronic devices that addresses these problems. Summary of the invention

[0005] According to several aspects of the present disclosure, a heat pipe is provided for cooling electronic components of a printed circuit board. The heat pipe includes a conduit having an inner diameter surface defining an inner hole, the conduit having a first end and a second end along the inner hole. The heat pipe also includes an adsorbent material coated on the inner diameter surface of the conduit. The heat pipe also includes a first liquid contained in the inner hole of the conduit and having a first boiling temperature. The heat pipe also includes a second liquid adsorbed by the adsorbent material and having a second boiling temperature higher than the first boiling temperature of the first liquid. In response to the conduit receiving heat from the electronic component and the first liquid reaching the first boiling temperature, the first liquid evaporates into a first vapor. The first vapor flows to the second end of the conduit, where the first vapor dissipates heat through the conduit and condenses into the first liquid. In response to the second liquid and the adsorbent material reaching a predetermined desorption temperature lower than the second boiling temperature, the second liquid is desorbed from the adsorbent material. In response to the second liquid reaching the second boiling temperature, the second liquid evaporates into a second vapor.

[0006] In one aspect, the adsorbent material is configured to desorb at least a portion of the second liquid into the inner pores before all of the first liquid evaporates into the first vapor.

[0007] In another aspect, the inner diameter surface defines at least one axial groove extending between the first end and the second end for drawing the first liquid from the second end to the first end by capillary action.

[0008] In another aspect, the plurality of axial grooves are circumferentially spaced from one another on the inner diameter surface.

[0009] In another aspect, the adsorbent material is spaced from the second end of the conduit so that the condensed first liquid flows from the inner bore to the axial groove. The adsorbent material is further spaced from the first end of the inner tube so that the first liquid returns from the axial groove to the inner bore.

[0010] In another aspect, the first liquid is water.

[0011] In another aspect, the second liquid is ethylene glycol.

[0012] According to several aspects of the present disclosure, an electronic device cooling system includes an electronic component that generates heat. The electronic device cooling system also includes a heat pipe for cooling the electronic component, and the heat pipe includes a conduit having an inner diameter surface defining an inner hole. The conduit has a first end and a second end along the inner hole. The heat pipe also includes an adsorbent material coated on the inner diameter surface of the conduit near the first end. The heat pipe also includes a first liquid, which is contained in the inner hole of the conduit and has a first boiling temperature. The heat pipe also includes a second liquid, which is adsorbed by the adsorbent material and has a second boiling temperature. The second boiling temperature of the second liquid is higher than the first boiling temperature of the first liquid. In response to the first end of the conduit receiving heat from the electronic component and the first liquid reaching the first boiling temperature, the first liquid evaporates into a first vapor. The first vapor moves toward the second end, where the first vapor dissipates heat through the conduit and condenses into the first liquid. In response to the second liquid and the adsorbent material reaching a predetermined desorption temperature lower than the second boiling temperature, the second liquid is desorbed from the adsorbent material. In response to the second liquid reaching the second boiling temperature, the second liquid evaporates into a second vapor. The electronic device cooling system also includes one or more thermocouples attached to at least one of the electronic component and the heat pipe for generating a first temperature signal associated with the temperature of the first liquid. The electronic device cooling system also includes a controller electrically connected to the thermocouple. In response to the controller receiving the first temperature signal from the thermocouple, the controller compares the temperature of the first liquid with a first temperature threshold. In response to the controller determining that the temperature of the first liquid is higher than the first temperature threshold, the controller generates a first warning notification signal. The controller is electrically coupled to a display device, and the display device is used to display a first warning indicating that the first liquid is approaching the first temperature threshold in response to the display device receiving the first warning notification signal from the controller.

[0013] In one aspect, the thermocouple generates a second temperature signal associated with the temperature of the second liquid. In response to the controller receiving the second temperature signal from the thermocouple, the controller compares the temperature of the second liquid to a second temperature threshold. In response to the controller determining that the temperature of the second liquid is above the second temperature threshold, the controller generates a second warning notification signal. In response to the display device receiving the second warning notification signal from the controller, the display device displays a second warning indicating that the temperature of the second liquid is approaching the second temperature threshold.

[0014] In another aspect, the electronic device cooling system further includes a fan that generates an airflow for cooling the second end of the conduit and the first vapor within the conduit.

[0015] In another aspect, the electronic device cooling system further includes a wicking material attached to the inner diameter surface adjacent the second end of the conduit, the wicking material being different from the sorbent material.

[0016] In another aspect, the wicking material is a layer of wicking material extending from the second end to a portion of the conduit adjacent the electronic component.

[0017] In another aspect, the absorbent material comprises a plurality of grooves and the wicking material further comprises a plurality of protrusions extending from the wicking material layer into the grooves of the absorbent material such that the wicking material draws the first liquid from the second end of the conduit to the first end.

[0018] In another aspect, the inner diameter surface defines a plurality of axial grooves extending between the first end and the second end for drawing the first liquid from the second end to the first end by capillary action. The axial grooves are circumferentially spaced from each other around the inner diameter surface.

[0019] In another aspect, the adsorbent material is spaced from the second end of the conduit so that the condensed first liquid flows from the inner bore to the axial groove. The adsorbent material is further spaced from the first end of the inner tube so that the first liquid returns from the axial groove to the inner bore.

[0020] In another aspect, the thermocouple includes a first thermocouple attached to the electronic component and generating a first temperature signal. The thermocouple also includes a second thermocouple attached to the heat pipe and generating a second temperature signal.

[0021] According to several aspects of the present disclosure, a method for operating an electronic device cooling system is provided. The electronic device cooling system includes an electronic component and a heat pipe attached to the electronic component. The heat pipe includes a conduit having an inner diameter surface defining an inner hole, an adsorbent material coated on the inner diameter surface, a first liquid contained in the inner hole, a second liquid adsorbed by the adsorbent material, one or more thermocouples attached to at least one of the electronic component and the heat pipe, and a controller. The method includes the step of transferring heat from the electronic component to the first liquid at the first end of the capped conduit. In response to the first liquid receiving heat from the electronic component and the first liquid reaching a first boiling temperature, the first liquid evaporates into a first vapor. The first vapor flows from the first end of the capped conduit to the second end of the capped conduit, where the first vapor dissipates heat through the conduit. In response to the first vapor dissipating heat through the conduit, the first vapor condenses into a first liquid. In response to the second liquid and the adsorbent material reaching a predetermined desorption temperature lower than the second boiling temperature, the second liquid is desorbed from the adsorbent material. In response to the second liquid reaching a second boiling temperature, the second liquid evaporates into a second vapor.

[0022] In one aspect, at least a portion of the second liquid is desorbed from the adsorbent material and disposed within the pores before all of the first liquid evaporates into the first vapor.

[0023] In another aspect, the first liquid is drawn from the second end to the first end by capillary action and passes through at least one axial groove formed in the inner diameter surface.

[0024] In another aspect, the thermocouple generates a first temperature signal associated with the temperature of the first liquid. In response to the controller receiving the first temperature signal from the thermocouple, the controller compares the temperature of the first liquid with a first temperature threshold. In response to the controller determining that the temperature of the first liquid is above the first temperature threshold, the controller generates a first warning notification signal. In response to the display device receiving the first warning notification signal from the controller, the display device displays a first warning indicating that the first liquid is approaching the first temperature threshold. The thermocouple generates a second temperature signal associated with the temperature of the second liquid. In response to the controller receiving the second temperature signal from the thermocouple, the controller compares the temperature of the second liquid with a second temperature threshold. In response to the controller determining that the temperature of the second liquid is above the second temperature threshold, the controller generates a second warning notification signal. In response to the display device receiving the second warning notification signal from the controller, the display device displays a second warning indicating that the temperature of the second liquid is approaching the second temperature threshold.

[0025] Other areas of applicability will become apparent from the description provided herein.It should be understood that the description and specific examples are intended for purposes of illustration only and are not intended to limit the scope of the present disclosure. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 is a perspective view of an example of an electronic device cooling system having an electronic component and a heat pipe for cooling the electronic component;

[0027] Figure 2 It was taken along line 2-2 Figure 1 A cross-sectional view of an example of a heat pipe in FIG.

[0028] Figure 3 It was taken along line 3-3 Figure 2 a cross-sectional view of a heat pipe in , showing the heat pipe having an inner diameter surface defining a plurality of axial grooves for drawing a condensed first liquid from a second end of the heat pipe to a first end of the heat pipe;

[0029] Figure 4 It shows Figure 1 A graph of various liquids in a heat pipe in cooling electronic components of a printed circuit board;

[0030] Figure 5 yes Figure 1 A cross-sectional view of another example of a heat pipe in , showing the heat pipe comprising a wicking material having an inner diameter surface without axial grooves;

[0031] Figure 6 It was taken along line 6-6 Figure 5 A cross-sectional view of a heat pipe in FIG. 1 showing an adsorbent material coated on an inner diameter surface;

[0032] Figure 7 It was taken along Route 7-7 Figure 5 A cross-sectional view of a heat pipe in FIG. 1 showing a wicking material coated on an inner diameter surface;

[0033] Figure 8 yes Figure 1 A cross-sectional view of yet another example of a heat pipe in FIG.

[0034] Fig. 9 It was taken along Route 9-9 Figure 8 A cross-sectional view of a heat pipe in , showing the coated wicking material having a plurality of protrusions extending from the entire wicking material layer into associated grooves of the adsorbent material;

[0035] Fig.10 It was taken along line 10-10 Figure 8 A cross-sectional view of a heat pipe in FIG. 1 , showing the entire wicking material layer.

[0036] Fig.11 yes Figure 1 A cross-sectional view of yet another example of a heat pipe in FIG. 1 shows that the thickness of the adsorbent material layer is less than the thickness of the wicking material layer.

[0037] Fig.12 Yes Operation Figure 2 A flow chart of an example of a method of printing a circuit board. DETAILED DESCRIPTION

[0038] The following description is merely exemplary in nature and is not intended to limit the present disclosure, application, or uses.

[0039] An exemplary electronic device cooling system includes a heat pipe having an adsorbent material to separate and recombine two or more liquids for cooling one or more electronic components. As described in the specific examples below, the heat pipe includes two liquids with two different boiling temperatures, one liquid is stored in the inner hole of the heat pipe, and the other liquid is stored in the adsorbent material. The two liquids provide a dual active hot zone (or a certain operating temperature range), and the heat pipe removes heat from the electronic components in the dual active hot zone. The operating temperature range can be between the lowest freezing point of the two liquids and the highest boiling point of the two liquids. Within this range, the liquid receives heat from the electronic components, thereby increasing the temperature of the liquid. It will be understood by those skilled in the art that heat can be transferred by removing heat from a heat source and causing the heat to flow to another substance (e.g., liquid), while the liquid may or may not reach its boiling temperature. As just one example, the operating temperature of a heat pipe with only water is between 32 degrees Fahrenheit (freezing point) and 212 degrees Fahrenheit (boiling point at sea level). Evaporation is evaporation on the water / air surface, and evaporation can occur at any temperature between the freezing point and the boiling point at 1 atmosphere while maintaining normal operation of the heat pipe. It is conceivable that the heat pipe can include more than two working liquids, and the adsorbent material can be arranged at any position relative to the electronic component to adjust the heat pipe to select the percentage of each liquid for cooling. In addition, the example of the system described in detail below is an open-loop passive system having a gravity-fed capped conduit having a first closed end adjacent to the electronic component and a second closed end adjacent to the cooling fan. However, it is conceivable that other examples of the system can be closed-loop active systems, including conduits forming a loop and pumps that pump condensate through the loop to return to the electronic component. In addition, the example of the adsorbent material described below is close to the electronic component, and it is conceivable that the adsorbent material is axially separated from the electronic component and forms an adsorbent material layer with any suitable thickness to achieve the relevant cooling characteristics. In other examples, different sections of the adsorbent material can initially store different liquids with different relevant boiling temperatures from each other, which are desorbed from the relevant sections of the adsorbent material at the relevant temperature to remove heat from the electronic component.

[0040] See also Figure 1 and Figure 2 , one example of an electronics cooling system 100 includes an electronic component 104 that generates heat in response to current flowing through the electronic component 104. The electronic component may be a processor, a driver circuit, a power supply circuit, a memory, or any other electronic component that generates heat in response to receiving current.

[0041] like Figure 2 and Figure 3As best shown, the system 100 also includes a heat pipe 106 for cooling the electronic component 104. The heat pipe 106 includes a conduit 108 having an inner diameter surface 110 defining an inner bore 112, and the conduit 108 has a first end 114 and a second end 116 along the inner bore 112 ( Figure 2 The inner diameter surface 110 defines one or more axial grooves 118 extending between the first end 114 and the second end 116 for drawing the first liquid 120 from the second end 116 to the first end 114 by capillary action, as described in detail below. Figure 3 As best shown, the axial grooves 118 are circumferentially spaced apart from one another at uniform distances about the inner diameter surface 110. It is contemplated that the grooves may be circumferentially spaced apart from one another at various uniform or non-uniform distances about the inner diameter surface.

[0042] The heat pipe 106 also includes an adsorbent material 122 coated on the inner diameter surface 110 of the conduit 108 and spaced apart from the first end 114 and the second end 116 of the conduit 108. In other words, the adsorbent material 122 is coated on the entire length of the inner diameter surface 110, except for a portion adjacent to the first end 114 and another portion adjacent to the second end 116. The adsorbent material 122 is configured to desorb at least a portion of the second liquid 124 into the inner pore 112 before the first liquid 120 is completely evaporated into the first vapor 126. It is contemplated that the adsorbent material can be coated on any portion of the inner diameter surface. The adsorbent material is selected from zeolites, silica gels, and metal organic frameworks. However, in other examples, the adsorbent material may include other suitable materials for desorbing and adsorbing the second liquid.

[0043] The first liquid 120 is contained within the inner bore 112 of the conduit 108 and has a first boiling temperature. In response to the conduit 108 and the first liquid 120 receiving heat from the electronic component 104 and the first liquid 120 reaching the first boiling temperature, the first liquid 120 evaporates into a first vapor 126. The first vapor 126 moves from the first end 114 to the second end 116, where the first vapor 126 dissipates heat through the conduit 108 and condenses into the first liquid 120.

[0044] The heat pipe 106 also includes a second liquid 124 that is adsorbed by the adsorbent material 122 and has a second boiling temperature that is higher than the first boiling temperature of the first liquid 120. In response to the second liquid 124 reaching the second boiling temperature, the second liquid 124 is desorbed from the adsorbent material 122 and evaporates into a second vapor 128. In this example, the first liquid 120 is water having a boiling temperature of 212 degrees Fahrenheit and the second liquid 124 is ethylene glycol having a boiling temperature of 387 degrees Fahrenheit. However, it is contemplated that the first liquid and the second liquid may be other suitable liquids having relevant boiling temperatures. Figure 4As shown, during the first stage 130 of cooling, the first liquid 120 receives heat, which causes the temperature of the first liquid 120 to increase to the first boiling temperature BT1 and evaporate. During the second stage 132 of cooling, the adsorbent material 122 and the second liquid 124 receive heat from the electronic component 104 until the temperature of the adsorbent material 122 and the second liquid 124 increases to a predetermined desorption temperature. The predetermined desorption temperature is lower than the second boiling temperature of the second liquid 124. More specifically, in this example, the predetermined desorption temperature is lower than the first boiling temperature of the first liquid 120 and the second boiling temperature of the second liquid 124. Therefore, before the first liquid 120 is completely evaporated, in response to the temperature of the adsorbent material 122 and the second liquid 124 reaching the predetermined desorption temperature, the second liquid 124 is released from the adsorbent material 122. In response to the temperature of the second liquid 124 reaching the second boiling temperature BT2, the second liquid 124 evaporates.

[0045] In one example, the adsorbent material 122 can release the second liquid 124 to combine with the first liquid 120 such that the boiling temperature of the resulting mixture can depend on the concentration of the mixture. Examples of boiling temperatures and concentrations of ethylene glycol in water can include the values ​​in the following table.

[0046]

[0047] The concentration or weight percentage of the solution may be controlled by at least one of using predetermined liquids having relevant boiling points, placing adsorbent materials holding these liquids at predetermined positions relative to the electronic components, and forming the adsorbent materials into an adsorbent material layer having a predetermined thickness.

[0048] See again Figure 2 , the system 100 also includes one or more thermocouples 134 attached to at least one of the electronic component 104 and the heat pipe 106, the thermocouple 134 generating a first temperature signal associated with the temperature of the first liquid and a second temperature signal associated with the temperature of the second liquid 124. More specifically, in this example, at least one thermocouple 134 includes a first thermocouple 136, which is attached to the electronic component 104 and generates a first temperature signal. At least one thermocouple 134 also includes a second thermocouple 138, which is attached to the heat pipe 106 and generates a second temperature signal. In other examples, the system includes a single thermocouple that is disposed within the inner bore of the conduit or at any other location and is attached to any portion of the heat pipe or the electronic component.

[0049] The system 100 also includes a controller 140 electrically connected to the thermocouple 134. In response to the controller 140 receiving a first temperature signal from the thermocouple 134, the controller 140 compares the temperature of the first liquid 120 to a first temperature threshold. In response to the controller 140 determining that the temperature of the first liquid 120 is above the first temperature threshold, the controller 140 generates a first warning notification signal. In this example, the first temperature threshold is a first boiling temperature of the first liquid, such as 212 degrees Fahrenheit associated with water. In response to the controller 140 receiving a second temperature signal from the thermocouple 134, the controller 140 compares the temperature of the second liquid 124 to a second temperature threshold. In response to the controller 140 determining that the temperature of the second liquid 124 is above the second temperature threshold, the controller 140 generates a second warning notification signal. Continuing with the previous example, the second temperature threshold is a second boiling temperature of the second liquid 124, such as 387 degrees Fahrenheit associated with ethylene glycol.

[0050] The controller 140 is also electrically coupled to a display device 142, which is used to display a first warning indicating that the first liquid 120 is approaching a first temperature threshold in response to receiving a first warning notification signal from the controller 140. In response to the display device 142 receiving a second warning notification signal from the controller 140, the display device 142 also displays a second warning indicating that the temperature of the second liquid 124 is approaching a second temperature threshold.

[0051] The system 100 also includes a fan 144 disposed between the second end 116 of the conduit 108 and the heat sink 117 extending from the conduit 108. Figure 2 ) to generate airflow above the duct 108 to dissipate heat.

[0052] See also Figures 5 to 7 , another example of heat pipe 206 is similar to Figure 2 The heat pipe 106 in FIG. 1 is similar to the heat pipe 106 in FIG. 1 and includes the same components identified by the same reference numerals increased by 100. Although Figure 2 and Figure 3 The heat pipe 106 in the embodiment has an axial groove 118 for returning the first liquid 120 from the second end 116 to the first end 114, but the inner diameter surface 210 of the heat pipe 206 does not have a groove. The heat pipe 206 includes a wicking material 250 that is coated on the inner diameter surface 210 and is different from the adsorbent material 222. The wicking material 250 extends from a portion of the inner diameter surface 210 adjacent to the second end 216 to a portion of the inner diameter surface 210 adjacent to the electronic component 204. After the first vapor 226 travels from the first end 214 to the second end 216 (where the first vapor 226 dissipates heat through the conduit 208 and condenses into the first liquid 220, causing the wicking material 250 to draw the first liquid 220 from the second end 216 to the first end 214), the wicking material 250 absorbs the first liquid 220. Although Figure 2 The heat pipe 106 in FIG. 1 includes a conduit 108 having an adsorbent material 122 extending from a portion proximate the first end 114 to another portion proximate the second end 116, but the heat pipe 206 includes an adsorbent material 222 coated only on a portion proximate the first end 214. The entire adsorbent material 222 and a portion of the electronic component 204 extend to the same extent relative to each other along the conduit 208, and another portion of the electronic component 204 extends axially beyond the adsorbent material 222.

[0053] See also Figures 8 to 10 , another example of heat pipe 306 is similar to Figures 5 to 7 The heat pipe 206 in FIG. 1 is a heat pipe 206 in FIG. 1 and includes like components identified by like reference numerals increased by 100. Figures 4 to 6 The entire adsorbent material 222 and only a portion of the electronic component 204 extend the same relative to each other along the conduit 208, while the entire electronic component 304 and a portion of the adsorbent material 322 extend the same relative to each other along the conduit 308, and another portion of the adsorbent material 322 extends axially beyond the electronic component 304. Figures 5 to 7 Compared to the heat pipe 206 in FIG. 1 , the heat pipe 306 includes an arrangement of the adsorbent material 322 relative to the electronic component 304, which can be arranged in a manner that is relatively Figures 5 to 7 The heat pipe 206 in the conduit 308 transfers heat to a larger amount of the second liquid 324 at a faster rate. In addition, the adsorbent material 322 includes a plurality of grooves 352, and the wicking material 350 includes a wicking material layer 354 extending from the adsorbent material 322 to the second end 316, and a plurality of protrusions 358 extend from the wicking material layer 354 to the grooves 352 of the adsorbent material 322, so that the first liquid 320 can be drawn from the second end 316 of the conduit 308 to the first end 314.

[0054] See also Fig.11 , another example of heat pipe 406 is similar to Figures 8 to 10 The heat pipe 306 of FIG. 1 is shown in FIG. 1 and includes the same components identified by the same reference numerals increased by 100. However, Figures 8 to 10 The entire electronic component 304 and only a portion of the adsorption material 322 extend to the same extent relative to each other, while the entire electronic component 404 and the entire adsorption material 422 extend to the same extent relative to each other. Figures 8 to 10 The adsorbent material 322 and the wicking material 350 each form an adsorbent material layer and a wicking material layer having equal thickness to each other, while the adsorbent material layer 458 formed by the adsorbent material 422 has a thickness less than the wicking material layer 454 of the wicking material 450 .

[0055] See also Fig.12 , provides an operation Figure 2The method 500 of the system 100 in FIG. 5 begins at step 502, where the electronic component 104 transfers heat to the first liquid 120 through the conduit 108. When the electronic component receives current, the electronic component or other parts of the system generate heat.

[0056] At step 504 , in response to the first liquid 120 receiving heat from the electronic component 104 and the first liquid 120 reaching a first boiling temperature, the first liquid 120 evaporates into the first vapor 126 .

[0057] At step 506 , the first thermocouple 136 generates a first temperature signal associated with the temperature of the first liquid.

[0058] In step 508, in response to the controller receiving the first temperature signal from the first thermocouple 136, the controller 140 compares the temperature of the first liquid 120 to a first temperature threshold. In this example, the first temperature threshold is the first boiling temperature. However, it is contemplated that the first temperature threshold may be higher or lower than the first boiling temperature. For example, to provide additional warning that the first liquid 120 is dry, the first temperature threshold may be a temperature lower than the first boiling temperature of the first liquid 120. If the temperature of the first liquid 120 is lower than the first temperature threshold, the method repeats step 508. If the temperature of the first liquid 120 is higher than the first temperature threshold, the method proceeds to step 510.

[0059] At step 510 , in response to the controller 140 determining that the temperature of the first liquid 120 is above a first temperature threshold, the controller 140 generates a first warning notification signal.

[0060] At step 512 , in response to the display device receiving the first warning notification signal from the controller 140 , the display device 142 displays a first warning indicating that the first liquid 120 is approaching a first temperature threshold.

[0061] At step 514 , the first steam 126 flows toward the second end 116 and the heat sink 117 , where the first steam 126 dissipates heat through the conduit 108 and the heat sink 117 .

[0062] At step 516 , in response to the first vapor 126 dissipating heat through the second end 116 of the conduit 108 , the first vapor 126 condenses into the first liquid 120 .

[0063] At step 518 , the first liquid 120 is drawn from the second end 116 to the first end 114 via the axial grooves 118 formed in the inner diameter surface 110 by capillary action.

[0064] In response to the second liquid 124 reaching the second boiling temperature, the second liquid 124 is desorbed from the adsorbent material 122 and evaporated into the second vapor 128 at step 520. In this example, at least a portion of the second liquid 124 is desorbed from the adsorbent material 122 into the inner pores 112 before the first liquid 120 is completely evaporated into the first vapor 126. This can be achieved by providing a liquid with a predetermined boiling point, an adsorbent material disposed in a variety of arrangements relative to the electronic component, and an adsorbent material layer having any suitable thickness.

[0065] At step 522 , the second thermocouple 138 generates a second temperature signal associated with the temperature of the second liquid 124 .

[0066] In step 524, in response to the controller 140 receiving the second temperature signal from the second thermocouple 138, the controller 140 compares the temperature of the second liquid 124 to a second temperature threshold. In this example, the second temperature threshold is the second boiling temperature. However, it is contemplated that the second temperature threshold may be higher or lower than the second boiling temperature. For example, in order to provide additional warning that the second liquid 124 is dry, the second temperature threshold may be less than the second boiling temperature of the second liquid 124. If the temperature of the second liquid 124 is lower than the second temperature threshold, the method repeats step 524. If the temperature of the second liquid 124 is higher than the second temperature threshold, the method proceeds to step 526.

[0067] At step 526 , in response to the controller 140 determining that the temperature of the second liquid 124 is above the second temperature threshold, the controller 140 generates a second warning notification signal.

[0068] In step 528, in response to the display device receiving the second warning notification signal from the controller 140, the display device 142 displays a second warning indicating that the temperature of the second liquid is close to the second temperature threshold. In this example, the second temperature threshold is the second boiling temperature. However, it is expected that the second temperature threshold can be higher or lower than the second boiling temperature. For example, in order to provide an additional warning that the second liquid 124 is dry, the second temperature threshold can be a temperature lower than the second boiling temperature.

[0069] The description of the present disclosure is merely exemplary in nature, and changes that do not depart from the general meaning of the present disclosure are included within the scope of the present disclosure. These changes should not be regarded as departing from the spirit and scope of the present disclosure.

Claims

1. A heat pipe for an electronic device cooling system having electronic components, the heat pipe comprising: a conduit having an inner diameter surface defining an inner bore, the conduit having a first end and a second end along the inner bore; an adsorbent material coated on the inner diameter surface of the conduit; a first liquid contained within the inner bore of the conduit and having a first boiling temperature; as well as a second liquid adsorbed by the adsorbent material and having a second boiling temperature higher than the first boiling temperature of the first liquid; wherein, in response to the conduit receiving heat from the electronic component and the first liquid reaching the first boiling temperature, the first liquid evaporates into a first vapor, and the first vapor moves toward the second end, where the first vapor dissipates heat through the conduit and condenses into the first liquid; wherein, in response to the second liquid and the adsorbent material reaching a predetermined desorption temperature below the second boiling temperature, the second liquid is desorbed from the adsorbent material, and in response to the second liquid reaching the second boiling temperature, the second liquid evaporates into a second vapor. 2 . The heat pipe of claim 1 , wherein the adsorbent material is configured to desorb at least a portion of the second liquid into the inner bore before all of the first liquid evaporates into the first vapor.

3. The heat pipe of claim 2, wherein the inner diameter surface defines at least one axial groove extending between the first end and the second end for drawing the first liquid from the second end to the first end by capillary action. 4 . The heat pipe of claim 3 , wherein the at least one axial groove comprises a plurality of axial grooves circumferentially spaced from one another on the inner diameter surface. 5 . The heat pipe of claim 4 , wherein the adsorbent material is coated on the inner diameter surface and is spaced apart from the first and second ends of the conduit. The heat pipe of claim 5 , wherein the first liquid is water.

7. The heat pipe of claim 6, wherein the second liquid is ethylene glycol.

8. An electronic device cooling system, comprising: Electronic components that generate heat; A heat pipe, used to cool the electronic component, the heat pipe comprising: a conduit having an inner diameter surface defining an inner bore, the conduit having a first end and a second end along the inner bore; an adsorbent material coated on the inner diameter surface of the conduit proximate the first end; a first liquid contained within the inner bore of the conduit and having a first boiling temperature; and a second liquid adsorbed by the adsorbent material and having a second boiling temperature higher than the first boiling temperature of the first liquid; wherein, in response to the conduit receiving heat from the electronic component and the first liquid reaching the first boiling temperature, the first liquid evaporates into a first vapor, and the first vapor moves toward the second end, where the first vapor dissipates heat through the conduit and condenses into the first liquid; and wherein, in response to the second liquid and the adsorbent material reaching a predetermined desorption temperature below the second boiling temperature, the second liquid is desorbed from the adsorbent material, and in response to the second liquid reaching the second boiling temperature, the second liquid evaporates into a second vapor; at least one thermocouple attached to at least one of the electronic component and the heat pipe, the at least one thermocouple generating a first temperature signal associated with a temperature of the first liquid; a controller electrically connected to the at least one thermocouple, the controller comparing the temperature of the first liquid to a first temperature threshold in response to the controller receiving the first temperature signal from the at least one thermocouple, and the controller generating a first warning notification signal in response to the controller determining that the temperature of the first liquid is above the first temperature threshold; The controller is electrically coupled to a display device, and the display device is configured to display a first warning indicating that the first liquid is approaching the first temperature threshold in response to the display device receiving the first warning notification signal from the controller.

9. The electronic device cooling system of claim 8, wherein the at least one thermocouple generates a second temperature signal associated with a temperature of the second liquid; in, in response to the controller receiving the second temperature signal from the at least one thermocouple, the controller comparing the temperature of the second liquid to a second temperature threshold; wherein, in response to the controller determining that the temperature of the second liquid is higher than the second temperature threshold, the controller generates a second warning notification signal; and wherein, in response to the display device receiving the second warning notification signal from the controller, the display device displays a second warning indicating that the temperature of the second liquid is close to the second temperature threshold.

10. The electronic device cooling system according to claim 9, further comprising: A fan generates an airflow for cooling the second end of the duct and the steam in the duct.

11. The electronic device cooling system according to claim 10, further comprising: A wicking material is attached to the inner diameter surface adjacent the second end of the catheter, the wicking material being different from the adsorbent material.

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