Method and controller for testing a two-phase cooling device, computer program and computer readable medium

Abstract

A method for testing a two-phase cooling device (20) is provided. The cooling device (20) has a housing (22) surrounding a cavity (24) and a cooling medium (32) within the cavity (24). The method includes controlling a temperature of ambient air of the cooling device (20) such that the cooling medium (32) within the cavity (24) transitions from its liquid state to its solid state and / or from its solid state to its liquid state while monitoring a first temperature (T1) of the cooling device (20); determining whether the monitored first temperature (T1) satisfies a predetermined criterion; and if the predetermined criterion is satisfied, determining that the cooling device (20) is overfilled with the cooling medium (32).

Description

Technical Field

[0001] This invention relates to the field of two-phase cooling equipment. In particular, this invention relates to methods and controllers for testing two-phase cooling equipment, computer programs for operating the controller, and computer-readable media in which the computer programs are stored. Background Technology

[0002] Advanced two-phase cooling devices for power electronics applications (e.g., 3D cooling devices (such as 2D vapor chambers) and / or 2D cooling devices (such as 2D heat pipes or thermosiphons)) are made of materials with high thermal conductivity, such as metals (e.g., copper), and rely on the use of a cooling medium (e.g., water) as the working fluid to obtain their optimal thermal properties.

[0003] Figure 1 An example of a two-phase cooling device 20, particularly a heat pipe or 2D vapor chamber according to the prior art, is shown. The cooling device 20 has a housing 22 surrounding a cavity 24, wherein an inner wall 26 of the housing 22 surrounds the cavity 24. The cavity 24 has a top region 28 and a bottom region 30. Figure 1 In this configuration, the orientation of the cooling device 20 is the same as its orientation during normal use. With this "normal" orientation, the top region 28 is positioned above the bottom region 30. The cooling medium 32 is located within the cavity 24. Furthermore, a porous structure can be arranged within the cavity 24. The porous structure can cover at least a portion of the inner wall 26 of the housing 22 and can extend from the top region 28 to the bottom region 30. The porous structure can be arranged to guide the condensed cooling medium 32 from the top region 28 to the bottom region 30.

[0004] The cooling device 20 is symmetrical with respect to the axis of symmetry 34. In the case of a 2D cooling device, the cooling device 20 is rotationally symmetric with respect to the axis of symmetry 34. In the case of a 3D cooling device, the cooling device 20 can be mirror symmetric, where the axis of symmetry 34 can represent the corresponding plane of symmetry.

[0005] In the case of water as the cooling medium 32, the cooling medium 32 freezes when cooled to below 0°C. While undergoing this phase change, if there is more water inside the cavity 24, such as if it can be contained in a porous structure, the water will accumulate in the bottom region 30 due to gravity and can form a liquid water bag, that is, a completely enclosed amount of liquid cooling medium at a certain point.

[0006] Figure 2 The bottom region 30 is shown, in which the cooling medium 32 exists as both a liquid cooling medium 36 and a frozen cooling medium 40. Due to the high thermal conductivity of the housing 22, the cooling medium 32 freezes from the outer periphery of the bottom region 30 toward the center of the bottom region 30, wherein... Figure 1 and Figure 2 In the bottom region 30, the center corresponds to the axis of symmetry 34 within the bottom region 30. Therefore, if the cooling medium 32 freezes, a pool of liquid cooling medium 36 is first formed in the middle of the frozen cooling medium 40. The liquid cooling medium 36, particularly the pool, has an upper surface 38. As long as the upper surface 38 of the liquid cooling medium 36 is present, the expansion of the frozen cooling medium 40 pushes the remaining liquid cooling medium 36 towards the top region 28 and prevents it from being subjected to high pressure. Therefore, even with the pool, the casing 22 will not bulge.

[0007] However, if the liquid coolant 36 begins to be surrounded by the frozen coolant 40, especially if the upper surface 38 of the liquid coolant 32 is sealed, the liquid coolant pool 36 is transformed into a sealed liquid coolant bag 36, and high pressure is generated on the inner wall 26 of the housing 22, which eventually leads to leakage of the coolant 32 in the bulges and / or bottom region 30 of the housing 22, and thus results in a loss of cooling performance.

[0008] Figure 3 It shows Figure 2 The bottom region 30 contains a cooling medium 32 that is frozen, causing a liquid cooling medium bag 36 to be surrounded by the frozen cooling medium 40. The pressure acting on the housing 22 due to the expansion of the frozen cooling medium 40 and the fact that the liquid cooling medium bag 32 is entirely within the frozen cooling medium 40 is indicated by two arrows showing the direction 42 of the corresponding expansion force. Deformation of the outer wall of the housing 22 can cause bulges that may lead to leakage (through which the liquid cooling medium 36 may leak to the outside of the housing 22), and / or loss of contact with the electronic components to be cooled. Both of these situations will result in malfunction of the cooling device 20 and / or the electronic components to be cooled.

[0009] The correct amount of liquid coolant 36 represents a trade-off between the cooling performance and reliability of the cooling device 20. Cooling performance is optimal with a specific, predetermined amount of water, where the reliability of the cooling device 20 decreases if the amount of liquid coolant 36 exceeds the capacity of the porous structure. Manufacturers of the cooling device 20 tend to fill the cavity 24 with slightly more coolant 32 as needed to maintain a safe level of cooling performance. However, overfilling of the cooling device 20 can lead to the aforementioned drawbacks. Therefore, it is important to determine whether the cavity 24 contains the correct amount of liquid coolant 36. Consequently, a method is needed for testing the two-phase cooling device 20, and particularly for testing whether the cooling device 20 is overfilled. Summary of the Invention

[0010] Therefore, one object of the present invention is to provide a method for testing two-phase cooling devices, particularly for testing whether a cooling device is overfilled, a method that can be easily performed, a method that can be performed without opening the cooling device and / or measuring the amount of cooling medium within the cooling device (e.g., by removing the cooling medium and measuring its volume), and / or a method that is highly accurate.

[0011] These objectives are achieved through the subject matter of the independent claims. Further exemplary embodiments are apparent from the dependent claims and the following description.

[0012] Specifically, the object of the present invention is achieved by a method for testing a two-phase cooling device. The cooling device has a housing surrounding a cavity and a cooling medium within the cavity. The method includes: controlling the temperature of the ambient air of the cooling device such that the cooling medium within the cavity changes from its liquid state to its solid state and / or from its solid state to its liquid state, while monitoring a first temperature of the cooling device; determining whether the monitored first temperature meets a predetermined criterion; and if the criterion is met, determining that the cooling device is overfilled with the cooling medium.

[0013] As mentioned above Figure 3 As explained, if the cooling device is overfilled, a pool of liquid cooling medium forms in the bottom region. If the cooling device is cooled to the freezing temperature of the cooling medium or lower, a closed bag of liquid cooling medium forms within the frozen cooling medium. Both the pool and the bag result in the cooling device having a significantly greater latent heat in the bottom region than in the top region. This effect can be accurately observed from the monitored first temperature during the phase change. Furthermore, the measurement and monitoring of the first temperature can be performed in a simple manner. Moreover, the method can be performed without opening the cooling device and / or measuring the amount of cooling medium within the cooling device (e.g., by removing the cooling medium and measuring its volume).

[0014] Therefore, the above-described method for testing two-phase cooling equipment, particularly for testing whether the cooling equipment is overfilled, can be easily performed, can be performed without opening the cooling equipment and / or measuring the amount of cooling medium inside the cooling equipment (e.g., by removing the cooling medium and measuring its volume), and / or is very accurate.

[0015] The two-phase cooling device can be a 3D cooling device (such as a 3D steam chamber) and / or a 2D cooling device (such as a 2D heat pipe or thermosiphon). The housing can include, or be made of, a metal with high thermal conductivity, such as copper. During normal use of the two-phase cooling device, the top region is positioned above the bottom region. The cooling medium can be, for example, water. The predetermined standard can be a predetermined temperature pattern over time. A first temperature of the cooling device can be monitored by receiving a signal from a first sensor, which can be positioned outside the housing and in thermal contact with the housing, thermally isolated from ambient air, and located in the bottom region.

[0016] If the predetermined criterion is a predetermined temperature pattern, a neural network can be trained and used to distinguish between the temperature patterns of overfilled and underfilled cooling devices. This training can be performed using training sets of temperature patterns from appropriately overfilled and underfilled cooling devices.

[0017] According to one embodiment, determining whether a monitored first temperature meets at least one predetermined criterion is achieved by defining at least one graph representing the first temperature monitored over time during the period in which the first temperature is monitored, and determining whether the graph meets the predetermined criterion. For example, if the first temperature is measured for a given duration (e.g., during at least one phase transition in a phase transition), the first temperature may not be measured continuously, but rather at regular time intervals, such as at intervals of seconds, for example, every 6 seconds or every 8 seconds. A trend line or average line can then be determined based on the measured temperature values, wherein the graph may correspond to the determined trend line or average line, respectively. This graph allows for a simple way to view the temperature behavior of the cooling device on a first side. Furthermore, this graph allows for easy mathematical analysis of the temperature behavior of the cooling device. The graph may consist of multiple temperature measurements at consecutive time points.

[0018] According to one embodiment, the graph of the monitored first temperature includes a first portion with a decreasing temperature, indicating supercooling of the coolant medium in its liquid state inside the cooling device; the graph then includes a jump to the freezing temperature of the coolant medium, indicating the onset of freezing of the coolant medium; the graph then includes a second portion at the freezing temperature of the coolant medium, indicating freezing of the coolant medium; and the graph then includes a third portion with a decreasing temperature; wherein a predetermined criterion is searched in the third portion. Searching for the predetermined criterion in the third portion only makes it possible to ignore measured temperature values ​​outside the third portion, or to make it possible to measure only the first temperature within the third portion. In both cases, the amount of measured temperature values ​​is reduced. Therefore, a smaller amount of data must be processed and analyzed. Therefore, searching for the predetermined criterion in the third portion only contributes to the simple and easy testing of the cooling device.

[0019] According to one embodiment, whether a graph meets a predetermined criterion is determined by: determining the first derivative of the graph; and determining the amount of extrema of the derivative of the graph during a phase transition and / or within a third part; wherein the predetermined criterion is met if the derivative of the signal has at least two extrema. The location of the extrema of the derivative corresponds to the location of the inflection point of the original graph. Each extremum can be a local maximum or local minimum of the derivative, and / or can be referred to as a “peak.” In an optimally filled cooling device, the cooling medium is absorbed within a porous structure with relatively uniform thickness and porosity. Therefore, the cooling medium is uniformly distributed over the cavity, and the phase transition also occurs very uniformly, and the derivative of the graph typically has only one extremum. Conversely, if the cooling device is overfilled, firstly, the aforementioned pool is formed, and then the aforementioned liquid cooling medium bag is formed. In this case, the cooling medium is not uniformly distributed over the cavity, and correspondingly, the phase transition of the cooling medium also occurs non-uniformly. This effect is reflected in the graph and can be easily seen from the derivative of the graph having at least two extrema. Therefore, determining the first derivative of the curve and calculating the number of extrema can help to accurately and easily identify whether the cooling equipment is overfilled.

[0020] According to one embodiment, whether a graph meets a predetermined criterion is determined by determining the width of the graph during at least one phase change period in the phase change of the cooling medium and / or within a third portion; wherein the predetermined criterion is met if the determined width is greater than a predetermined width threshold. As described above, in an optimally filled cooling device, the cooling medium is uniformly distributed over the cavity. Therefore, the latent heat density along the cooling device is relatively constant. During cooling of the cooling device by convection of ambient air, the heat flux is also relatively uniformly distributed across the surface of the cooling device's shell. Conversely, due to the formation of pools and bags in an overfilled cooling device, the bottom region of the cooling device in which pools and bags are formed has a much larger latent heat. Therefore, for cooling media in porous structures, the phase change continues in the bottom region of the cooling device even after the phase change has been completed, during cooling or heating of the cooling medium throughout its freezing temperature. The more excess cooling medium collected in the bottom region, the longer the phase change takes. Therefore, overfilled cooling devices tend to experience long phase changes during freezing and melting. The duration of the phase change is reflected in the width of the graph showing the phase change. Therefore, determining the width of the graph during at least one phase change in the phase change of the cooling medium and / or within the third part, and determining that a predetermined criterion is met if the determined width is greater than a predetermined width threshold, helps to accurately and easily determine whether the cooling device is overfilled.

[0021] According to one embodiment, the first temperature is sensed at the bottom region of the housing, and the method further includes: monitoring a second temperature of the cooling device, wherein the second temperature is sensed at the upper portion of the housing while monitoring the first temperature; and determining the difference between the monitored first temperature and the second temperature during at least one phase change in the phase change of the cooling medium and / or within a third portion; if the determined difference is greater than a predetermined difference threshold, a predetermined criterion is met. As described above, in an optimally filled cooling device, the latent heat density along the cooling device is relatively constant, and the heat flux is also relatively uniformly distributed across the surface of the housing of the cooling device. Therefore, the temperature along the cooling device is relatively constant, and the difference between the first temperature and the second temperature will be very small. Conversely, due to the formation of pools and bags in an overfilled cooling device, the cooling device has a much larger latent heat in the bottom region than in the top region. Therefore, for an overfilled cooling device, the difference between the first temperature and the second temperature is quite large. Therefore, if this difference is greater than a predetermined difference threshold, it can be determined that the cooling device is overfilled.

[0022] According to one embodiment, the first temperature is monitored for a predetermined amount of time. For example, the first temperature can be monitored from the start of the test (when cooling of the cooling device begins) to the end of the test (when the cooling device again has its initial temperature). Alternatively, the first temperature can be monitored only from the start of freezing until the end of melting of the cooling medium. Alternatively, the first temperature can be monitored only from the start of freezing of the cooling medium until the end of freezing. Alternatively, the first temperature can be monitored only from the start of melting of the cooling medium until the end of melting. It is advantageous if overfilling of the cooling device is determined by calculating the amount of the extrema of the first derivative or by analyzing the width of the graph, if the first temperature is monitored for only one phase transition, or if the first temperature is monitored throughout the test but only those values ​​monitored during one phase transition are analyzed. If overfilling of the cooling device is determined by counting the amount of the extrema of the first derivative, then a criterion with at least two extrema only relates to one phase transition. In other words, when analyzing the first derivative of a graph during two phase transitions, the corresponding derivative must have at least four extrema in order to classify overfilled cooling equipment.

[0023] According to one embodiment, the method further includes arranging a cooling device in a temperature chamber that surrounds the ambient air and enables temperature control of the ambient air before controlling the temperature of the ambient air.

[0024] According to one embodiment, the method further includes placing a first sensor on the housing before controlling the temperature of the ambient air, such that the first sensor is in thermal contact with the housing and thermally isolated from the ambient air.

[0025] According to one embodiment, a first sensor is disposed in the bottom region of the housing. Due to the formation of the bag and pool, the effects of overfilling of the cooling device can be best observed in the bottom region. Therefore, the effect on the first temperature is strongest in the bottom region. Thus, disposing the first sensor in the bottom region and sensing the first temperature accordingly in the bottom region can help to determine very easily and accurately whether the cooling device is overfilled.

[0026] The aforementioned features, advantages, and / or effects of the method for testing a two-phase cooling device can be transferred to the controller for testing the two-phase cooling device, the computer program for operating the controller, and / or the computer-readable medium on which the computer program is stored, as described below. Therefore, repetition of these features, advantages, and / or effects is omitted, and reference is made to the above explanation only for the purpose of providing a concise description.

[0027] The objective of this invention is achieved through a controller for testing a two-phase cooling device. The controller includes a processor and a memory. The processor is configured to execute the methods described above.

[0028] The object of the present invention is achieved by a computer program for operating the controller, which, when executed by a processor, is adapted to perform the above-described method.

[0029] The object of the present invention is achieved by a computer-readable medium having the above-described computer program stored thereon.

[0030] These and other aspects of the invention will become clear from the embodiments described below and will be set forth with reference to the embodiments described below. Attached Figure Description

[0031] The subject matter of the present invention will be explained in more detail below with reference to exemplary embodiments shown in the accompanying drawings.

[0032] Figure 1 A two-phase cooling device according to the prior art is schematically shown.

[0033] Figure 2 A schematic detailed view of a two-phase cooling device in its first state according to the prior art is shown.

[0034] Figure 3 The illustration shows the basis for being in the second state. Figure 2 Two-phase cooling equipment.

[0035] Figure 4 An exemplary embodiment of a two-phase cooling device according to the present invention under test conditions is illustrated schematically.

[0036] Figure 5 The first figure shows several graphs representing the temperatures of the same cooling device with different amounts of cooling medium during the freezing and melting of the cooling medium.

[0037] Figure 6 The second and third graphs, each comprising several curves, are shown, representing the temperature of the same cooling device with different amounts of cooling medium during the freezing of the cooling medium.

[0038] Figure 7 The fourth and fifth figures, each comprising several graphs, are shown, representing the temperatures of the same cooling device with varying amounts of cooling medium during the melting of the cooling medium.

[0039] Figure 8 The sixth figure shows several graphs representing the temperatures of different cooling devices with varying amounts of cooling medium during freezing.

[0040] Figure 9 The seventh figure is shown, including representations based on Figure 8The first derivative of the temperature curves of different cooling devices.

[0041] Figure 10 The eighth figure shows several graphs representing the temperatures of different cooling devices with varying amounts of cooling medium during melting.

[0042] Figure 11 Figure 9 is shown, including representations based on Figure 10 The first derivative of the temperature curves of different cooling devices.

[0043] Figure 12 A flowchart illustrating an exemplary embodiment of a method for testing a two-phase cooling device according to the present invention is shown.

[0044] Figure 13 A flowchart illustrating an exemplary embodiment of a method for determining whether a predetermined criterion is met, according to the present invention, is shown.

[0045] Figure 14 A flowchart illustrating an exemplary embodiment of a method for determining whether a predetermined criterion is met, according to the present invention, is shown.

[0046] Figure 15 A flowchart illustrating an exemplary embodiment of the method for determining whether a predetermined criterion is met according to the present invention is shown.

[0047] The reference numerals used in the accompanying drawings and their meanings are listed in summary form in the reference numeral list. In principle, the same parts have the same reference numerals in the accompanying drawings. Detailed Implementation

[0048] Figure 1 A two-phase cooling device 20 according to the prior art is schematically shown. The cooling device 20 can be a 3D cooling device (e.g., a 3D steam chamber) or a 2D cooling device (e.g., a 2D heat pipe or thermosiphon). The cooling device 20 can be used to cool electronic components (not shown). Electronic components can be electronic circuits, integrated circuits, chips, transformers, etc.

[0049] The cooling device 20 includes a housing 22. The housing 22 may comprise a material with high thermal conductivity, such as a metal, like copper, or may be made of it. The housing 22 surrounds a cavity 24. The cavity 24 is surrounded by an inner wall 26 of the housing 24. Figure 1In this configuration, the orientation of the cooling device 20 is the same as during normal use (i.e., when cooling electronic components). With this "normal" orientation, the top region 28 of the cooling device 20 is above the bottom region 30. A cooling medium 32 (e.g., water) is disposed within the cavity 24. Furthermore, the cooling device 20 may include a porous structure (not shown) that may be disposed at the inner wall 26 and / or over the entire cavity 24. The cooling device 20 is symmetrical with respect to an axis of symmetry 34. In the case of a 2D cooling device, the cooling device 20 may be rotationally symmetrical with respect to the axis of symmetry 34. In the case of a 3D cooling device, the cooling device 20 may be mirror-symmetrical, where the axis of symmetry 34 may represent a corresponding plane of symmetry.

[0050] Prior to the use of the cooling device 20, the cooling medium 32 is in a liquid state. During normal use of the cooling device 20, the cooling device 20 is in thermal contact with the electronic components to be cooled, at least in the bottom region 30, and at least partially absorbs the heat generated by the operation of the electronic components. If the cooling device 20 absorbs sufficient heat from the electronic components, the cooling medium 32 at least partially changes from a liquid state to a gaseous state. The gaseous cooling medium 32 rises to the top region 28 and condenses in the top region 28. The condensed cooling medium 32 is guided from the top region 28 to the bottom region 30 by a porous structure. If all of the cooling medium 32 is in a liquid state, at least a portion of the cooling medium 32 is absorbed within the porous structure. If the liquid cooling medium 32 in the cavity 24 exceeds the amount that can be absorbed by the porous structure, the remaining portion of the cooling medium 32 accumulates in the bottom region 30.

[0051] Figure 2 A two-phase cooling device 20 according to the prior art (e.g., according to...) is schematically shown. Figure 1 A detailed view of the cooling device 20 in its first state. In this first state, a portion of the cooling medium 32 is frozen, while the remainder remains liquid. Specifically, a pool 36 of liquid cooling medium with an upper surface 38 is partially embedded within the frozen cooling medium 40. If the freezing process continues, the liquid cooling medium 36 can be pushed upwards by the expansion of the frozen cooling medium 40, provided that the upper surface 38 of the pool is open and thus exists. However, due to the higher thermal conductivity of the material of the housing 22, the upper surface 38 of the pool can be closed by the frozen cooling medium 40 and may therefore disappear.

[0052] Figure 3 The illustration shows the basis for being in the second state. Figure 2The two-phase cooling device 20. In the second state, a liquid coolant bag 36 is formed. The liquid coolant bag 36 is completely surrounded by frozen coolant 40. If the freezing process continues, the frozen coolant 40 further increases and expands, but the liquid coolant 36 cannot be pressed upwards because the bag is closed. Then, an expansion force is generated, which acts on the inner wall 26 of the housing 22 in an outwardly pointing direction 42. This expansion force can cause a bulge in the housing 22, and if the bulge occurs, it can lead to leakage in the housing 22.

[0053] If only those cooling devices 20 are used for applications at or below the freezing temperature of the cooling medium 32 (where these cooling devices 20 are not overfilled and / or the entire liquid cooling medium 36 can be absorbed by the porous structure), the formation of associated bulges in the liquid cooling medium bag 36 and the housing 22, as well as leakage of the housing 22, can be avoided. In this case, it should be noted that a very small amount of excess cooling medium, i.e., more liquid cooling medium 36 than the porous structure can absorb, can be tolerated. The corresponding cooling device 20 can be classified as not overfilled because, if the cooling medium 32 freezes, this very small amount of excess cooling medium will not damage the cooling device 20 due to the elasticity of the material of the housing 22 of the cooling device 20. For example, a cooling device 20 with 1% to 7% (e.g., 2% to 6%, e.g., 5%) of excess cooling medium 32 can still be considered not overfilled. Instead, this additional amount can be provided to ensure the expected cooling performance without damaging the housing 22 of the cooling device 20.

[0054] The inventors of this invention have recognized that the temperature behavior of the cooling device 20 during the phase transition of the cooling medium 32 from its liquid state to its frozen state or vice versa can indicate whether the cooling device 20 is overfilled.

[0055] Figure 4 An exemplary embodiment of a two-phase cooling device 20 according to the present invention under test conditions is illustrated schematically. Cooling device 20 may correspond to the cooling device 20 described above. In test conditions, cooling device 20 may be arranged in a temperature chamber. The temperature chamber includes ambient air, the temperature of which may be controlled. Specifically, the temperature may be controlled such that the ambient air and cooling device 20 may be cooled below the freezing temperature of the cooling medium 32.

[0056] A first sensor 44 for measuring a first temperature of the cooling device 20 can be disposed on the outer periphery of the housing 22. Specifically, the first sensor 44 can be disposed in the bottom region 30 of the housing 22. The first sensor 44 can be in thermal contact and / or direct contact with the housing 22. For example, the first sensor 44 can be fixed to the housing 22 by a thin layer of thermally conductive adhesive. The first sensor 44 can be thermally isolated from ambient air by a first thermal insulation element 46.

[0057] Optionally, a second sensor 50 for measuring a second temperature of the cooling device 20 can be disposed on the outer periphery of the housing 22. Specifically, a second sensor 44 can be disposed on the housing 22 above the first sensor 44 (e.g., in the top region 28). The second sensor 50 can be in thermal contact and / or direct contact with the housing 22. For example, the second sensor 50 can be fixed to the housing 22 by a thin layer of thermally conductive adhesive. The second sensor 50 can be thermally isolated from ambient air by a second thermal insulation element 52.

[0058] The first sensor 44 and the second sensor 50 may be electrically coupled to the controller 48. The controller 48 may be arranged to receive a first signal from the first sensor 44 and a second signal from the second sensor 50. The first signal may represent a first temperature. The second signal may represent a second temperature. The controller 48 may be configured to monitor the first temperature and / or the second temperature for a predetermined period of time, such as throughout the test, during the transition of the cooling medium from its liquid state to its solid state and subsequently from its solid state to its liquid state, or only during one of these phase transitions. Furthermore, the controller 48 may be configured to analyze the monitored first temperature and / or second temperature in relation to whether the cooling device 20 is overfilled. In other words, the controller 48 may be configured to perform methods for testing the cooling device 20, particularly regarding whether the cooling device 20 is overfilled. Furthermore, the controller 48 may be configured to control the temperature of the ambient air in the temperature chamber. The controller 48 may include a processor and memory. The controller 48 may be considered and / or may be coupled to a computer. If the controller 48 is coupled to a computer, one or more of the above-described tasks of the controller 48 may be outsourced to the computer.

[0059] Figure 5 A first graph is shown, comprising several curves representing the temperatures of the same type of cooling device 20 with varying amounts of cooling medium 32 during the freezing and melting of the respective cooling medium 32. The cooling device 20 may correspond to the aforementioned cooling device 20. For example, the cooling device 20 is arranged in the aforementioned temperature chamber, in which the temperature of the ambient air can be controlled.

[0060] Cooling device 20 can cool from 10°C to -10°C starting at t=0 min. The temperatures of the ambient air and cooling device 20 are represented by the corresponding curves in Figure 1. According to... Figure 5 The ambient air temperature drops from 10°C to -10°C within the first five minutes. All other graphs representing the temperature of the cooling device 20 show roughly similar behavior. Specifically, in the first part of the corresponding graph, all temperatures except the ambient air temperature drop to between -4°C and -8°C. This behavior can be termed supercooling and occurs before the cooling medium 32 begins to freeze. The amount of supercooling is independent of the amount of cooling medium 32 within the cooling device 20 and can vary slightly for different test cycles.

[0061] At some point during the cooling process, Figure 5 At approximately t = 7 min, the freezing of the cooling medium 32 begins, and the temperature sensed by sensors 44 and 50 simultaneously jumps to 0°C. Following this jump is the second part of the graph, which represents the period of uniform freezing of the cooling medium 32, during which the temperature remains close to 0°C.

[0062] After the second part, in Figure 5 In the third part, between t=10min and t=15min, the temperature begins to drop again. At the beginning of the third part, near the first sensor 44, freezing is complete, but not yet complete in the bottom region 30, where a pool of liquid cooling medium 36 exists. The housing 22 (which typically has high thermal conductivity and / or may be made of, for example, copper) provides a thermal connection between the first sensor 44 and the frozen liquid cooling medium 36 at the bottom. This is why the temperature measured by the first sensor 44 will never reach ambient temperature as long as some of the cooling medium 32 remains liquid at the bottom. After the third part, freezing is complete everywhere within the cavity 24, and there is no longer any liquid cooling medium 36 in the cavity 24, indicating that freezing is complete. If the cooling device 20 is overfilled, the temperature profile within this third part varies sharply depending on the amount of cooling medium 32 within the cooling device 20. Therefore, this third part can be used to determine whether the cooling device 20 is overfilled, as described below.

[0063] After the third part, the temperature was maintained below -10°C for the predetermined duration, such as Figure 5 As shown, this continues until t = 65 min. Then, the ambient air temperature rises to 10°C. Except for the overcooling effect, all temperatures exhibit behavior during this heating process that is the opposite but similar to that during the cooling period. Specifically, the ambient air temperature jumps to 10°C within 5 min (t = 70 min). The temperature of the cooling device 20 rises fairly uniformly until 0°C, which corresponds to the first part of the cooling process.

[0064] Then, the melting of the cooling medium 32 begins, and the temperature is maintained at around 0°C for about 5 to 10 minutes, which corresponds to the second part of the cooling process.

[0065] After that, Figure 5 During this process, between approximately t = 73 min and t = 90 min, the temperature begins to rise again, corresponding to the third part, indicating that melting is complete, but not simultaneously. If the cooling device 20 is overfilled, the temperature profile within this part will vary drastically depending on the amount of cooling medium 32 within the cooling device 20. Therefore, this part of the melting process, corresponding to the third part of the cooling process, can be used to determine whether the cooling device 20 is overfilled, as described below. After this part, the test can be stopped, and the results can be evaluated.

[0066] Figure 6 Second and third figures, each comprising several graphs, are shown, representing the temperatures of the same cooling device 20 with varying amounts of cooling medium 32 during the freezing of the cooling medium. Specifically, Figure 6 The second image shown above the third image is... Figure 5 A detailed view of the temperature profile of the overfilled cooling device 20 (i.e., the first cooling device S1). The third figure is... Figure 5 Detailed views of the temperature profiles of the properly filled cooling device 20 (i.e., the second cooling device S2) are shown. These detailed views pertain only to the cooling process. Detailed views of the melting process are shown in... Figure 7 As shown in the image.

[0067] Figures 2 and 3 show graphs of the ambient temperature T_amb inside the corresponding cooling device 20, the internal temperature T_in inside the corresponding cooling device 20, and the first temperature T1, the second temperature T2, the third temperature T3, and the fourth temperature T4, measured by sensors located at the housing 22 of the corresponding cooling device 20. Specifically, the first temperature T1 and the second temperature T2 can be sensed by the corresponding first sensor 44 and the corresponding second sensor 50, respectively. The third temperature T3 and the fourth temperature T4 can be sensed using corresponding additional sensors (not shown) attached to the housing 22 in the top region 28, with the distance between these sensors and the corresponding bottom region 30 increased.

[0068] First, as described above, the cooling device 20 can begin cooling from 10°C to -10°C at t = 0 min. In both graphs, the ambient temperature T_amb drops to -10°C within the first five minutes. Due to the aforementioned supercooling effect, in the first part of both graphs, all other temperatures T_in, T1, T2, T3, and T4 drop to between -4°C and -8°C.

[0069] At approximately t = 7 min, freezing of the cooling medium 32 begins, and temperatures T_in, T1, T2, T3, and T4 simultaneously jump to 0°C. This jump is followed by the second part of the graph, representing the period of uniform freezing of the cooling medium 32, during which the temperature remains close to 0°C. In the second graph representing the temperature of the overfilled cooling device 20, the duration of the second part varies depending on the position of the corresponding sensors 44 and 50 at the housing 22. This is because the cooling medium 32 first completes freezing in the top region 28 of the cooling device 20, where it is uniformly distributed within the porous structure. Conversely, in the bottom region 28, additional cooling medium 32 accumulates, for example, with a pool, and freezing ends last. A comparison of the second and third graphs shows that this difference is significant only for the overfilled cooling device 20 illustrated by the second graph. Conversely, for the optimally filled cooling device 20 illustrated by the third graph, freezing occurs almost simultaneously along the entire height of the cooling device 20, except at the very top where the fourth temperature T4 is measured.

[0070] Similarly, in the third portion where temperatures T_in, T1, T2, T3, and T4 decrease again, there is a significant difference between the properly filled cooling device 20 (illustrated by the third curve) and the overfilled cooling device 20 (illustrated by the second curve). Specifically, in the third curve, temperatures T_in, T1, T2, T3, and T4 decrease fairly uniformly. Conversely, in the second curve, the first to fourth temperatures T1, T2, T3, and T4, measured at the housing 22 of the corresponding cooling device 20, decrease non-uniformly, with the corresponding curve showing at least two inflection points.

[0071] A possible explanation for the observed differences between cooling devices 20 with different fillings is as follows: In the optimally filled cooling device 20, the liquid cooling medium 32 is essentially absorbed within a porous structure with relatively uniform thickness and porosity. Therefore, the latent heat density along the cooling device 20 is relatively constant. During cooling of the cooling device 20 via ambient air convection, the heat flux is distributed relatively uniformly across the outer surface of the cooling device 20. Therefore, the freezing of the liquid cooling medium 36 or the melting of the frozen cooling medium 40 (see reference) Figure 8(To be explained) The liquid cooling medium 36 in the porous structure begins and ends approximately simultaneously. Conversely, in the vertically oriented, overfilled cooling device 20, the liquid cooling medium 36 forms a pool or pouch 36 in the bottom region 30. Therefore, the cooling device 20 has a much larger latent heat in the bottom region 30 compared to the top region 28 of the same cooling device 20. During cooling or heating across 0°C, freezing / melting continues in the bottom region 30 of the cooling device 20 even after the phase change of the cooling medium 32 in the porous structure has been completed. Therefore, due to the high thermal conductivity of the walls and the porous structure of the cooling device 20, the temperature of the walls cannot change freely until the pools and / or pouches in the bottom region 30 are completely frozen or melted, respectively. This results in the widening of the third section, particularly the widening of the curves within the third section, resulting in the widening of two or more inflection points of the curves within the third section, and resulting in the differences between the curves of temperatures T1, T2, T3, and T4 measured by the corresponding sensors 44, 50 outside the housing 22 of the cooling device 20 within the third section. The more excess liquid cooling medium 36 collected in the bottom region 30, the wider the third part of the freezing transition is shown, and the wider the melting transition is also shown.

[0072] Therefore, whether one of the cooling devices 20 is overfilled can be determined by analyzing the width of the curves from the first temperature to the fourth temperature T1, T2, T3, T4, the difference between the curves of temperature T1, T2, T3, and T4, and / or the amount of inflection points in the curves, each curve within the third section. For example, a width threshold can be predetermined such that if the width of at least one temperature curve in the temperature curves of the cooling device 20 within the third section is greater than the predetermined width threshold, it can be determined that the cooling device 20 is overfilled. Alternatively or additionally, a difference threshold can be predetermined such that if the difference between the temperature measured in the top region 28 (e.g., the fourth temperature T4) and the temperature measured in the bottom region 30 (e.g., the first temperature T1) within the third section is greater than a predetermined difference threshold, it can be determined that the cooling device 20 is overfilled. Alternatively or additionally, if there are two or more inflection points in the corresponding temperature curves within the third section, the amount of the inflection point in at least one temperature curve in the temperature curve corresponding to the temperature in the bottom region 30 (e.g., the first temperature T1) can be determined, and it can be determined that the cooling device 20 is overfilled. The inflection point can be determined directly, or it can be derived from the first derivative of the corresponding temperature curve, where the location of the local extremum of the derivative corresponds to the location of the inflection point of the original curve.

[0073] Figure 7 Figures four and five, each comprising several graphs, are shown, representing the temperatures of the same cooling device 20 with varying amounts of cooling medium 32 during the melting of the cooling medium 32. Specifically, Figure 7The fourth image shown above the fifth image is... Figure 5 A detailed view of the temperature profile of the overfilled cooling device 20 shown. Figure 5 is... Figure 5 Detailed views of the temperature profiles of the properly filled cooling device 20 are shown. These detailed views only pertain to the melting process. Detailed views of the freezing process are shown above. Figure 6 As shown. During the melting process, different portions of the graph broadly correspond to the reverse freezing process. In particular, the graphs for the first to fourth temperatures T1, T2, T3, and T4 show the same non-uniform behavior as they did during the freezing process in the portion corresponding to the third portion, i.e., between approximately t = 7 min and approximately t = 24 min. Therefore, based on the determinations made above during the freezing process, it is possible to determine whether the cooling device 20 is overfilled by analyzing the temperatures during the melting process, particularly the temperature graphs.

[0074] Therefore, whether one of the cooling devices 20 is overfilled can be determined by analyzing the width of the curves from the first temperature to the fourth temperature T1, T2, T3, T4, the difference between the curves of temperature T1, T2, T3, and T4, and / or the amount of inflection points of the curves, each curve being within the "melting" portion corresponding to the third portion during freezing. For example, a width threshold can be predetermined such that if the width of at least one temperature curve in the temperature curves of the cooling device 20 corresponding to the melting portion is greater than a predetermined width threshold, it can be determined that the cooling device 20 is overfilled. Alternatively or additionally, a difference threshold can be predetermined such that if the difference between the temperature measured in the top region 28 (e.g., the fourth temperature T4) and the temperature measured in the bottom region 30 corresponding to the melting portion is greater than a predetermined difference threshold, it can be determined that the cooling device 20 is overfilled. Alternatively or additionally, if two or more inflection points exist within the corresponding melting portion of the temperature curve, the amount of an inflection point in at least one temperature curve corresponding to the temperature in the bottom region 30 (e.g., the first temperature T1) can be determined, and it can be determined that the cooling device 20 is overfilled. The inflection points can be determined directly or derived from the first derivative of the corresponding temperature curve, where the location of a local extremum of the derivative corresponds to the location of an inflection point in the original curve.

[0075] Figure 8A sixth figure is shown, comprising several graphs representing the temperatures of different cooling devices 20 with varying amounts of cooling medium 32 during freezing. Specifically, the first cooling device S1 is overfilled, the second cooling device S2 has an appropriate amount of cooling medium 32, and the third cooling device S3 has a fixed amount of cooling medium 32 supplied by the manufacturer of the cooling devices 20. Cooling devices S1, S2, and S3 correspond to cooling device 20 and differ from each other only in the amount of cooling medium 32 they contain. Figure 8 As can be seen from the graph, only the temperature curve of the overfilled first cooling device S1 shows the wide phase transition and two inflection points in the third part.

[0076] Figure 9 The seventh figure is shown, including representations based on Figure 8 The first derivative of the temperature curves of different cooling devices 20. From Figure 9 As can be seen from the graph, only the derivative of the curve of the overfilled first cooling device S1 shows two extreme values ​​in the third part, which are local minima in this case.

[0077] Figure 10 Figure 8 is shown, comprising several graphs representing the temperatures of different cooling devices 20 with varying amounts of cooling medium 32 during melting. The first to third cooling devices S1, S2, and S3 correspond to the aforementioned first to third cooling devices S1, S2, and S3. From Figure 10 As can be seen from the graph, only the temperature curve of the overfilled first cooling device S1 shows the wide phase transition and two inflection points in the third part.

[0078] Figure 11 Figure 9 is shown, including representations based on Figure 10 The first derivative of the temperature curves of different cooling devices 20. From Figure 11 It can be seen that only the derivative of the curve of the overfilled first cooling device S1 shows two extreme values ​​in the third part, which are local maxima in this case.

[0079] Figures 5 to 11The graphs of the first to fourth temperatures T1, T2, T3, and T4, and their derivatives, correspond to different temperature patterns. These patterns vary depending on whether the corresponding cooling device 20 is overfilled and the location of the housing 22 at which the corresponding temperature is measured. Therefore, in cases where no corresponding temperature is measured at or near the top of the corresponding cooling device 20, all temperature graphs of an overfilled cooling device 20 show the same or at least similar temperature patterns. The template for the temperature patterns can be predetermined and can be used, for example, via a neural network to distinguish the temperature patterns of an overfilled cooling device 20 from those of a properly filled cooling device 20. The predetermined temperature patterns may include a corresponding graph width greater than the aforementioned width threshold and / or two or more inflection points, each inflection point being within a third section.

[0080] Figure 12 A flowchart illustrating an exemplary embodiment of a method according to the present invention for testing a two-phase cooling device, particularly for testing one of the aforementioned cooling devices 20, S1, S2, and S3. This method can be used to test whether the corresponding cooling device 20 is overfilled with the cooling medium 32. It should be noted herein that in some cases, overfilling up to about 5% can be considered non-critical and / or not overfilled, because in these cases, the pool and / or pouch 36 of liquid cooling medium formed in a 5% overfilled cooling device 20 will not damage the cooling device 20 during freezing. For example, the elasticity of the material of the housing 22 can allow slight deformation caused by the pool and / or pouch of the housing, so that no corresponding defects and / or damage occur.

[0081] In optional step A2, a temperature sensor (e.g., first sensor 44 and second sensor 50) is attached to the housing 22 of the cooling device 20 to be tested, for example, as described above. Figure 4 If the test is performed by analyzing the width of a temperature curve and / or the magnitude of the inflection points of the curve or the extreme values ​​of the corresponding derivatives, then the first sensor 44 is sufficient to perform the method. If the test is performed by analyzing the temperature differences measured at different locations on the housing 22, then the second sensor 50 is required to perform the method.

[0082] In optional step A4, a cooling device 20, including multiple sensors 44, 50, can be arranged in a temperature chamber. Specifically, the cooling device 20 is arranged vertically, as shown during normal use, and as per [reference to...] Figures 1 to 4 As shown.

[0083] In step A6, the temperature of the ambient air is controlled, for example, the ambient temperature T_amb described above. Specifically, the ambient air temperature can be controlled such that the cooling medium 32 within the cooling device 20 under test undergoes a phase change from its liquid state to its solid state and then a phase change from its solid state to its liquid state, only a phase change from its liquid state to its solid state, or only a phase change from its solid state to its liquid state. Hereinafter, it is assumed that only the phase change from liquid to solid is monitored and analyzed to test the cooling device 20. However, this method can be easily extended to monitor and analyze both phase changes, or only the phase change from solid to liquid. For example, in the case of water as the cooling medium 32, the ambient temperature T_amb can be controlled, for example, by controller 48, such that it spans 0°C, for example, from 10°C to -10°C.

[0084] In step A8, the temperature of the cooling device 20 can be monitored, for example, a first temperature T1. Additionally, another temperature of the cooling device 20 can be monitored, such as a second temperature T2, a third temperature T3, and / or a fourth temperature T4. Specifically, the multiple temperatures can be monitored during a third period, which corresponds to the frozen portion of the corresponding graph.

[0085] In optional step A10, multiple graphs representing the monitored temperatures(s) ...(s))(s)(s)(s)(s)(

[0086] In step A12, it is determined whether the monitored temperature meets the predetermined standard. The following will discuss... Figure 13 , Figure 14 and Figure 15 The different options for determining whether the monitored temperature meets a predetermined criterion are explained. If the predetermined criterion is met, the method proceeds in step A14. If the predetermined criterion is not met, the method proceeds in step A16.

[0087] In step A14, it is determined that the cooling device 20 being tested is overfilled.

[0088] In step A16, it is determined that the cooling device 20 being tested is not overfilled.

[0089] Figure 13 A flowchart illustrating an exemplary embodiment of the method for determining whether a predetermined criterion is met according to the present invention is shown. Figure 13 The method can be found in the discussion about Figure 12 The method is implemented within the explanation, for example, as a subroutine. Specifically, Figure 13 The method can be used as Figure 12 The method is executed in step A12.

[0090] In step A20, the determination can be made, for example, through corresponding mathematical applications. Figure 12The derivative of the curve determined in step A10 of the method.

[0091] In step A22, for example, during the duration of at least one phase transition in a phase transition, such as in the third part, the amount of the extreme value of the derivative is determined.

[0092] In step A24, if an extreme value is determined for only one phase transition, it is determined whether the magnitude of the extreme value is 2 or more. If the magnitude of the extreme value is 2 or more, the method proceeds to step A26. If the magnitude of the extreme value is less than 2, the method proceeds to step A28. Alternatively, if both phase transitions are monitored, it is determined whether the magnitude of the extreme value is 4 or more.

[0093] In step A26, it is determined that the predetermined criteria are met.

[0094] In step A28, it is determined that the predetermined criteria are not met.

[0095] Figure 14 A flowchart illustrating an exemplary embodiment of the method for determining whether a predetermined criterion is met according to the present invention is shown. Figure 14 The method can be found in the discussion about Figure 12 The method is implemented within the explanation, for example, as a subroutine. Specifically, Figure 14 The method can be used as Figure 12 The method is executed in step A12.

[0096] In step A30, during at least one phase transition in the phase transition, for example within the third part, it is determined that... Figure 12 The width of the curve determined in step A10 of the method.

[0097] In step A32, it is determined whether the width of the graph is greater than a predetermined width threshold. If the width of the graph is greater than the predetermined width threshold, the method proceeds to step A34. If the width of the graph is not greater than the predetermined width threshold, the method proceeds to step A36.

[0098] In step A34, it is determined that the predetermined criteria are met.

[0099] In step A36, it is determined that the predetermined criteria are not met.

[0100] Figure 15 A flowchart illustrating an exemplary embodiment of the method for determining whether a predetermined criterion is met according to the present invention is shown. Figure 15 The method can be found in the discussion about Figure 12 The method is implemented within the explanation, for example, as a subroutine. Specifically, Figure 15 The method can be used as Figure 12 The method is executed in step A12.

[0101] In step A40, the second temperature T2, which has already been sensed by the second sensor 50 in the top region 28, can be monitored.

[0102] In step A42, for example, during the duration of at least one phase transition in a phase transition, such as in the third part, the difference between the monitored first temperature T1 and the second temperature T2 is determined.

[0103] In step A44, it is determined whether the determined difference is greater than a predetermined difference threshold. If the determined difference is greater than the predetermined difference threshold, the method proceeds to step A46. If the determined difference is not greater than the predetermined difference threshold, the method proceeds to step A48.

[0104] In step A46, it is determined that the predetermined criteria are met.

[0105] In step A48, it is determined that the predetermined criteria are not met.

[0106] While the invention has been described and illustrated in detail in the accompanying drawings and foregoing description, such description and illustration are to be considered illustrative or exemplary, not restrictive; the invention is not limited to the disclosed embodiments. Other variations to the disclosed embodiments can be understood and implemented by those skilled in the art and those practicing the claimed invention through a study of the drawings, this disclosure, and the appended claims. In the claims, the word "comprising" does not exclude other elements or steps, and the indefinite articles "a" or "an" do not exclude a plural. A single processor or controller or other unit may perform the functions of several items described in the claims. The fact that certain measures are listed only in mutually different dependent claims does not imply that a combination of these measures cannot be used for advantageous purposes. No reference numerals in the claims should be construed as limiting the scope.

[0107] List of reference numerals

[0108] 20: Cooling equipment

[0109] 22: Shell

[0110] 24: cavity

[0111] 26: Inner wall of the shell

[0112] 28: Top area

[0113] 30: Bottom area

[0114] 32: Cooling medium

[0115] 34: Axis of symmetry

[0116] 36: Liquid cooling medium

[0117] 38: Upper surface of liquid cooling medium

[0118] 40: Frozen cooling medium

[0119] 42: Direction of expansion force

[0120] 44: First Sensor

[0121] 46: First insulation

[0122] 48: Controller

[0123] 50: Second sensor

[0124] 52: Secondary insulation

[0125] S1: First cooling device

[0126] S2: Second cooling equipment

[0127] S3: Third Cooling Equipment

[0128] T_amb: Ambient temperature

[0129] T_in: Internal temperature

[0130] T1: First temperature

[0131] T2: Second temperature

[0132] T3: Third Temperature

[0133] T4: Fourth Temperature

[0134] A2-A48: Steps Two through Forty-Eight

Claims

1. A method for testing a two-phase cooling device (20), the cooling device (20) having a housing (22) surrounding a cavity (24) and a cooling medium (32) within the cavity (24), the method comprising: The temperature of the ambient air in the cooling device (20) is controlled so that the cooling medium (32) in the cavity (24) changes from its liquid state to its solid state and / or from its solid state to its liquid state, while the first temperature (T1) of the cooling device (20) is monitored. Determine whether the monitored first temperature (T1) meets at least one predetermined criterion; and If the predetermined criteria are met, it is determined that the cooling device (20) is overfilled by the cooling medium (32).

2. The method of claim 1, wherein whether the monitored first temperature (T1) meets at least one of the predetermined criteria is determined by: Determine at least one graph, said at least one graph representing the first temperature (T1) monitored over time during the period when the first temperature (T1) is monitored, and Determine whether the curve meets the predetermined criteria.

3. The method according to claim 2, wherein The graph of the monitored first temperature (T1) includes a first portion with a decreasing temperature indicating supercooling of the cooling medium (32) in a liquid state inside the cooling device (20), followed by a jump to the freezing temperature of the cooling medium (32) indicating the start of freezing of the cooling medium (32), then a second portion of the graph at the freezing temperature of the cooling medium (32) indicating freezing of the cooling medium (32), and then a third portion of the graph with a decreasing temperature; wherein the predetermined criterion is searched in the third portion.

4. The method of claim 3, wherein whether the graph meets the predetermined criterion is determined by the following means: Determine the first derivative of the curve; and The amount by which the extreme values ​​of the derivative of the graph are determined during a phase transition and / or within the third part; If the derivative of the signal has at least two extreme values, then the predetermined criterion is satisfied.

5. The method according to claim 3, wherein the graph is determined to satisfy the predetermined criterion by determining the width of the graph during at least one phase change in the phase change of the cooling medium (32) and / or within the third portion; wherein the predetermined criterion is satisfied if the determined width is greater than a predetermined width threshold.

6. The method of claim 3, wherein the first temperature (T1) is sensed at the bottom region (30) of the housing (22), the method further comprising: The second temperature (T2) of the cooling device (20) is monitored, wherein the second temperature (T2) is sensed in the top region (28) of the housing (22) while the first temperature (T1) is being monitored; as well as Determine the difference between a first temperature (T1) and a second temperature (T2) monitored during at least one phase change in the cooling medium (32) and / or within the third part; If the determined difference is greater than a predetermined difference threshold, then the predetermined standard is satisfied.

7. The method according to any one of claims 1 to 6, wherein the first temperature (T1) is monitored for a predetermined long period of time.

8. The method according to any one of claims 1 to 6, further comprising: Before controlling the temperature of the ambient air, the cooling device (20) is arranged in a temperature chamber that surrounds the ambient air and is capable of controlling the temperature of the ambient air.

9. The method according to any one of claims 1 to 6, further comprising: Before controlling the temperature of the ambient air, a first sensor (44) is arranged in the housing (22) such that the first sensor (44) is in thermal contact with the housing (22) and is thermally isolated from the ambient air.

10. The method according to claim 9, wherein the first sensor (44) is disposed at the bottom region (30) of the housing (22).

11. A controller (48) for testing a two-phase cooling device (20), the controller comprising a processor and a memory, wherein the processor is configured to perform the method according to any one of claims 1 to 6.

12. A computer program product for operating a controller (48) for testing a two-phase cooling device (20), said computer program product being adapted, when executed by a processor, to perform the method according to any one of claims 1 to 7.

13. A computer-readable medium storing a computer program product according to claim 12.

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