Heat conduction fluid for indirect liquid cooling systems

Abstract

This invention relates to the use of an aliphatic diester-based thermal conductive fluid for indirectly cooling electronic components.

Description

Technical Field

[0001] This application relates to the use of aliphatic diester-based heat transfer fluids for the indirect cooling of electronic components.

Background Art

[0002] Today, heat dissipation is a relevant topic in the design and operation of devices with electronic components, particularly semiconductor-type circuit components such as those of electronic circuits packaged at high density, particularly integrated circuit components. Heat dissipation is a critical problem, for example, in modern server farms, telecommunications centers, and data centers. In these, due to the continuous increase in the number of hard disks, microprocessors or central processing units (CPUs), and their processing and storage power, overheating that can cause failures and irreparable damage to such electronic components is prevented, and heat dissipation is an important factor.

[0003] Therefore, in the field of the design and operation of electronic devices, there is a strong need to identify and develop new and improved cooling systems.

[0004] Today, there are various cooling systems that use various techniques to dissipate heat from electronic components to maintain an appropriate operating temperature, and they can be classified based on the type of heat transfer fluid and whether heat conduction occurs through direct or indirect contact with the electronic components.

[0005] Indirect cooling systems are designed to dissipate the heat generated by electronic components without directly contacting the heat transfer fluid with such components. Depending on the physical state and type of the heat transfer fluid, and the mechanism of heat dissipation, common types of indirect cooling systems are: Air Cooling Systems: This type of cooling system is the most widely used method for indirect cooling of electronic components. Air cooling systems utilize fans and heat sinks for heat dissipation. Fans, either active (powered) or passive (reliant on natural convection), promote airflow around the heat sink, improving heat dissipation. Air cooling systems are relatively simple, cost-effective, and suitable for many applications. However, their effectiveness may be limited in high-power or densely packaged systems. Phase Change Cooling Systems: Phase change cooling systems involve the use of a refrigerant that changes phase from liquid to gas and then back again. The cooling process begins with the refrigerant absorbing heat from the electronic components and evaporating it into a gas. The gaseous refrigerant is then condensed back into a liquid by a heat exchanger, releasing the absorbed heat. The liquid refrigerant then flows back into the components, repeating the cycle. Liquid Cooling Systems: Liquid cooling systems use a liquid thermal conductive fluid to conduct heat from electronic components. This method is more efficient than air cooling systems, and the required system is less expensive and less complex than a phase-change cooling system.

[0006] Typically, an indirect liquid cooling system includes a cooling loop for circulating a heat conduction fluid, a pumping system for circulating the heat conduction fluid throughout the cooling loop, a heat conduction element coupled to an electronic component to absorb heat from the electronic component and conduct heat to the heat conduction fluid, a heat exchanger for dissipating the heat absorbed by the heat conduction fluid and cooling it, and optionally a container for housing the heat conduction fluid. In these systems, the heat conduction fluid is pumped through the cooling loop by the pumping system and comes into thermal contact with the heat conduction element, and in this way the heat conduction fluid absorbs heat from the heat conduction element. Thereafter, the heat conduction fluid dissipates the heat generated by the electronic component, and the heat exchange fluid is cooled by the heat exchanger before being recirculated in the loop, or stored in a container before being recirculated in the loop, where it is cooled at that time.

[0007] Therefore, the heat-conducting fluid used in liquid cooling systems plays a crucial role in heat dissipation and the performance of the system itself, in terms of its rheological and hydrodynamic properties, thermal and chemical stability, and heat capacity characteristics. Today, known fluids for indirect liquid cooling include water and special fluids, among which those containing PFAS (perfluoro and polyfluoro materials) have found a wide range of applications. [Overview of the project] [Problems that the invention aims to solve]

[0008] However, the applicant noted that even though water is a common choice due to its excellent thermal properties and availability, overcoming the risk of corrosion and fouling, which can lead to the destruction and damage of cooling systems and electronic components, requires the implementation of complex and expensive purification systems. At the same time, water has a limited operating temperature range, which further limits the cooling efficiency of systems using it.

[0009] The applicant also noted that while special fluids, such as those containing PFAS, may possess improved properties such as higher boiling points or better corrosion resistance, enabling their use in specific applications, these compounds have recently demonstrated technical and application limitations.

[0010] In fact, PFAS tend to be highly volatile, and this volatility leads to partial loss of these fluids due to the evaporation of PFAS when exposed to high-temperature components. This high volatility and partial loss of PFAS necessitates their refilling into the heat exchange system, and at the same time, makes operators more susceptible to exposure to the fluid.

[0011] At the same time, concerns related to the environmental impact of PFAS have also been raised, making the use of PFAS particularly serious and requiring the adoption of complex and expensive containment systems to avoid any diffusion and / or contact with the external environment during operation, transport, and maintenance of systems and equipment using PFAS.

[0012] Therefore, an object of the present invention is to provide a novel thermal conductive fluid that can overcome the functional and environmental limitations of thermal conductive fluids currently used in indirect liquid cooling systems for electronic components, and the applicant has surprisingly found that certain types of aliphatic diester-based thermal conductive fluids can be effectively used for such purposes. [Means for solving the problem]

[0013] In particular, the first embodiment relates to the use of a thermal conductive fluid comprising at least one diester of at least one C2-C9 aliphatic diol and at least one linear or branched C2-C7 aliphatic monocarboxylic acid for cooling electronic components in an indirect liquid cooling system.

[0014] Surprisingly, the applicant has found that such diesters exhibit suitable rheological and hydrodynamic properties, thermal and chemical stability, and heat capacity properties that are effectively suitable for use in indirect liquid cooling systems for dissipating heat generated by electronic components.

[0015] Advantageously, the diester can also provide a more environmentally sustainable solution for PFAS-based specialty fluids, reducing the complexity of operation, transport, and maintenance of cooling systems.

[0016] In particular, the diesters offer an excellent alternative to PFAS-based fluids due to their remarkably low dynamic viscosity, especially at cryogenic temperatures. This superior property enables efficient pumping and circulation of heat transfer fluids, even in the most extreme cold environments. Furthermore, these esters benefit from a high flash point and low volatility, ensuring both the safety and effective cooling of electronic equipment at high temperatures. The unique combination of low viscosity, high flash point, and low volatility makes these diesters an ideal choice for various types of indirect electronic cooling systems, providing efficient thermal management for a wide range of electronic equipment and offering reliable and highly efficient heat transfer capabilities while prioritizing safety and performance.

[0017] These fluids, due to their low viscosity, facilitate the effective conduction of heat from electronic components in different types of indirect cooling systems. The high flash points and low volatility of these esters ensure safe operation while minimizing the risk of fire or malfunction in such systems.

[0018] For example, such diesters can be used as fluids that function in heat pipes or narrow channels or conduits, which are widely used for indirectly cooled electronic equipment. These diesters enable efficient heat conduction under such conditions, allowing heat to be absorbed from the heat source and dissipated in the sink. The low viscosity of the fluid at the operating temperature ensures optimal circulation through narrow channels or conduits, thereby improving overall cooling performance even when contact time and heat conduction surface area are limited.

[0019] In contrast to direct cooling systems, particularly those using immersion baths where the heat-conducting fluid does not pass through a narrow space and the contact time and heat-conducting surface area are greater than in indirect cooling systems, the low viscosity of the fluid at the operating temperature is a significantly stringent viscosity requirement.

[0020] Therefore, in an indirect cooling system having a closed loop, such diesters can advantageously act as heat transfer fluids circulating through the closed loop system. Since these fluids have a low dynamic viscosity at the operating temperature, they can easily flow through narrow channels and intricate cooling structures, and can efficiently carry away heat from electronic components. The high flash point and low volatility enhance the safety and reliability of the cooling system.

[0021] Therefore, the diesters can advantageously also be effectively used in a cold plate cooling system that can flow through a metal plate in direct contact with the electronic components. The low viscosity of these fluids enables efficient heat conduction and enables effective cooling of high-power electronic devices. The high flash point and low volatility of these esters ensure safe operation and minimize the risk of fluid leakage or system damage.

[0022] Thus, more efficient and safe use of an electronic device in which an electronic component is mounted can be achieved by improving the thermal management of the electronic component and avoiding or at least significantly suppressing overheating phenomena that can lead to failure and irreparable damage of the electronic component mounted in the electronic device.

[0023] In addition, the low viscosity of the diesters at low temperatures enables setting and using a high constant temperature difference between the high-temperature electronic component and the heat transfer fluid, making heat exchange more effective and rapid. Maintaining the temperature as constant as possible and avoiding or eliminating heat changes as quickly as possible are actually basic requirements for cooling electronic components, especially semiconductor-based electronic components.

[0024] In a further aspect, the present invention also relates to a method of cooling an electronic component using an indirect liquid cooling system. The liquid cooling system includes a heat transfer fluid defined in the first aspect of the present invention.

[0025] In yet another aspect, the present invention relates to an electronic device including: at least one electronic component, and At least one indirect liquid cooling system containing at least one heat transfer fluid defined in the first aspect of the present invention, suitable for cooling the electronic component.

Advantages of the Invention

[0026] The advantages of the method and the electronic device according to these aspects of the present invention have already been disclosed with respect to the use according to the first aspect of the present invention and will not be repeated here.

Modes for Carrying Out the Invention

[0027] In a first aspect, the present invention relates to the use of a heat transfer fluid containing at least one diester of at least one C2-C9 aliphatic diol and at least one linear or branched C2-C7 aliphatic monocarboxylic acid for cooling an electronic component in an indirect liquid cooling system.

[0028] Surprisingly, the applicant has found that such diesters exhibit appropriate rheology and hydrodynamic properties, thermal stability and chemical stability, and heat capacity properties, and that these properties effectively suit such diesters for use in an indirect liquid cooling system for dissipating heat generated by electronic components.

[0029] Within the scope of this specification and the subsequent claims, unless otherwise indicated, all numerical values representing amounts, parameters, percentages, etc. should be understood to be preceded by the term "about" in all cases. As used herein, the term "about" is understood by those skilled in the art and varies somewhat in the context in which it is used. When referring to measurable values such as amounts, durations, etc. as used herein, the term "about" means including variations of ±20% or ±10% from a particular value, for example ±5%, ±1%, and ±0.1%, and such variations are appropriate for implementing the disclosed method.

[0030] Furthermore, all ranges of numerical values ​​include all possible combinations of the maximum and minimum values, and all possible intermediate ranges in addition to the intermediate ranges specifically shown below herein.

[0031] Unless otherwise defined, all technical and scientific terms used herein have the same meanings as those generally understood by those skilled in the art to which the present invention pertains.

[0032] As used herein, the articles "a" and "an" refer to one or more (i.e., at least one) grammatical objects of the article. For example, "an element" means one or more elements.

[0033] As used herein, the expression “indirect liquid cooling system” means a cooling system in which the heat conduction fluid is in a liquid state or primarily in a liquid state during the operation of the system, and which is suitable for cooling the components to be cooled, but does not come into direct contact with these components. In particular, when referring to electronic components, an indirect liquid cooling system is a cooling system in which the heat conduction fluid does not come into direct contact with such electronic components, for example, by the interposition of different elements made of a thermally conductive material such as copper or other metals that are thermally coupled to the electronic components and interposed between the electronic components and the heat conduction fluid. These thermally conductive elements have the function of preventing direct contact between the fluid and the electronic components and conducting heat. In an indirect cooling system, such different elements interposed between the electronic components and the heat conduction fluid may have different shapes and configurations (heat sinks, walls inside tubes, or plates) depending on the design of the system.

[0034] In indirect cooling by heat conduction, both conduction and convection are involved, as the fluid exchanges heat with the thermally bonded material of the component to be cooled, and the heat exchange is primarily influenced by the temperature difference between the component to be cooled and the heat-conducting fluid.

[0035] The present invention may exist in one or more of the features or embodiments described below.

[0036] According to the present invention, the heat-conducting fluid comprises at least one diester of at least one C2-C9 aliphatic diol and at least one linear or branched C2-C7 aliphatic monocarboxylic acid.

[0037] Preferably, the C2-C9 aliphatic diol is selected from the group consisting of ethylene glycol, 1,2-propanediol, 1,3-propanediol, 1,4-butanediol, 1,3-butanediol, diethylene glycol, triethylene glycol, dipropylene glycol, neopentyl glycol, 2-methyl-1,3-propanediol, 1,5-pentanediol, 1,6-hexanediol, 3-methyl-1,5-pentanediol, 2-butyl-2-ethyl-1,3-propanediol, 2,2,4-trimethyl-1,3-pentanediol, and mixtures thereof.

[0038] Preferably, the aliphatic diol of the diester according to the present invention is a C3-C6 aliphatic diol, and more preferably, is selected from the group consisting of 1,3-propanediol, 1,4-butanediol, 1,3-butanediol, diethylene glycol, triethylene glycol, dipropylene glycol, neopentyl glycol, 2-methyl-1,3-propanediol, 1,5-pentanediol, 1,6-hexanediol, 3-methyl-1,5-pentanediol, and mixtures thereof. Even more preferably, the aliphatic diol of the diester according to the present invention is a C3-C5 aliphatic diol selected from the group consisting of 1,3-propanediol, 1,4-butanediol, 1,3-butanediol, diethylene glycol, neopentyl glycol, 2-methyl-1,3-propanediol, 1,5-pentanediol, and mixtures thereof.

[0039] In a preferred embodiment, the aliphatic diol of the diester according to the present invention is selected from the group consisting of 1,2-propanediol, 1,3-propanediol, neopentyl glycol, and mixtures thereof, and is preferably selected from the group consisting of 1,2-propanediol, 1,3-propanediol, and mixtures thereof.

[0040] In one embodiment of the present invention, the linear or branched C2-C7 aliphatic monocarboxylic acid of the diester according to the present invention is a C3-C5 aliphatic monocarboxylic acid, more preferably selected from the group consisting of propanoic acid, butyric acid, isobutyric acid, 2-methylbutyric acid, 3-methylbutyric acid, valeric acid, and mixtures thereof, and more preferably selected from the group consisting of 2-methylbutyric acid, 3-methylbutyric acid, valeric acid, and mixtures thereof.

[0041] In another embodiment of the present invention, the linear or branched C2-C7 aliphatic monocarboxylic acid of the diester according to the present invention is a C5-C7 aliphatic monocarboxylic acid, and preferably, in such an embodiment, at least one of the monocarboxylic acids of the diester according to the present invention is a C5 acid. More preferably, in such an embodiment, the aliphatic monocarboxylic acid of the diester according to the present invention is a C5 acid, optimally valeric acid.

[0042] In preferred embodiments of the present invention, the diester is selected from the group consisting of neopentyl glycol divalellarate, 1,2-propanediyl divalellarate, 1,3-propanediyl divalellarate, 2-methyl-1,3-propanediyl divalellarate, and mixtures thereof, and more preferably from the group consisting of 1,2-propanediyl divalellarate, 1,3-propanediyl, and mixtures thereof.

[0043] The diols, monocarboxylic acids, and diesters defined above, surprisingly, exhibit a combination of properties such as low dynamic viscosity at temperatures down to -55°C and high volume resistivity, combined with a flash point higher than 125°C. This makes them particularly suitable and operationally efficient in indirect electronic cooling systems over a wide temperature range of -55°C to 125°C, and therefore particularly efficient as components of heat-conducting fluids for indirect liquid cooling systems of electronic components.

[0044] In addition to diesters, the thermal conductive fluid according to the present invention may advantageously contain one or more other components, such as synthetic or natural esters, mineral oil, polyethers such as polyalkylene glycols, polyolefins, and additives.

[0045] In one embodiment, the heat-conducting fluid according to the present invention comprises at least one diester as defined above, and at least one C6-C 12 Aliphatic monoalcohols, and at least one linear or branched C2-C2 chain. 12 It includes at least one monoester with an aliphatic monocarboxylic acid, such as monoesters like 2-propylheptanylvalerate and 2-ethylhexanylheptanoate.

[0046] Preferably, the heat-conducting fluid according to the present invention comprises at least one additive selected from the group consisting of antioxidants, pour point depressants, defoamers, corrosion inhibitors, viscosity modifiers, wear inhibitors and / or extreme pressure agents, friction modifiers, cleaning agents, dispersants, and mixtures thereof.

[0047] Advantageously, the heat-conducting fluid according to the present invention exhibits one or more of the following characteristics: Kinematic viscosity less than 50 mPa·s at -30°C; Flash point of 125°C or higher; Volume resistivity at 25°C higher than 0.1 teraohm-centimeter (TΩ·cm).

[0048] Furthermore, the thermal conductive fluid according to the present invention exhibits a heat capacity and thermal conductivity characteristics suitable for cooling electronic components.

[0049] Preferably, the heat-conducting fluid according to the present invention is in a liquid state during the operation of the indirect liquid cooling system.

[0050] In the indirect liquid cooling system according to the present invention, the heat-conducting fluid has the function of dissipating heat generated by electronic components, and the electronic components may, advantageously, be mounted in an electronic device.

[0051] In indirect cooling by heat conduction, a fluid exchanges heat with a thermally bonded material containing the component to be cooled. Both conduction and convection are involved, as the heat exchange is primarily influenced by the temperature difference between the component and the heat-conducting fluid. Another well-known factor influencing heat exchange is the amount of heat-exchange fluid used, which is limited by the design of the cooling system.

[0052] Thanks to the advantageous properties of the heat-conducting fluid according to the present invention, the indirect liquid cooling system may be any type of indirect liquid cooling system known to those skilled in the art for indirectly cooling electronic components, and is not particularly limited.

[0053] Preferably, the indirect liquid cooling system according to the present invention comprises at least one thermally conductive element thermally coupled to the electronic component, wherein the thermally conductive element is suitable for conducting heat from the electronic component to the thermally conductive fluid. More preferably, the thermally conductive element is selected from the group consisting of walls, layers, heat sinks, cold plates, heat pipes, and steam chambers.

[0054] Preferably, the indirect liquid cooling system includes: A liquid cooling loop suitable for circulating the aforementioned heat-conducting fluid; A pump suitable for supplying the heat-conducting fluid throughout the liquid cooling loop; A heat exchanger for cooling the aforementioned heat-conducting fluid, Optionally, a container suitable for containing the heat-conducting fluid.

[0055] According to the present invention, the electronic component may be any type of electronic component that tends to generate heat during use and therefore needs to be cooled, or which may fail and suffer irreparable damage after overheating.

[0056] Preferably, the electronic component is selected from the group consisting of a microprocessor, semiconductor wafer, power control semiconductor, electrochemical cell, distributed switchgear, power transformer, circuit board, multichip module, hard disk, central processing unit, packaged or unpackaged semiconductor device, fuel cell, laser, and semiconductor integrated circuit.

[0057] More preferably, the electronic component is selected from the group consisting of a microprocessor, semiconductor wafer, power control semiconductor, circuit board, multichip module, hard disk, central processing unit, packaged or unpackaged semiconductor device, and semiconductor integrated circuit.

[0058] Preferably, the electronic component is mounted in an electronic device.

[0059] According to the present invention, the electronic device may be an electronic device on which electronic components are mounted, and is not particularly limited. Preferably, the electronic device is selected from the group consisting of computers, servers, server farms, telecommunications centers, and data centers.

[0060] Thanks to the properties of the heat-conducting fluid according to the present invention, it is possible to improve the thermal management of electronic components and avoid or significantly suppress overheating phenomena that can lead to failure and irreparable damage, thereby realizing a more efficient and safer cooling method for electronic components.

[0061] Accordingly, in a further embodiment, the present invention also relates to a method for cooling an electronic component in an indirect liquid cooling system, wherein the liquid cooling system comprises a thermal conductive fluid comprising at least one diester of at least one C2-C9 aliphatic diol and at least one linear or branched C2-C7 aliphatic monocarboxylic acid as defined in the first embodiment of the present invention.

[0062] The advantages and preferred features of this method have already been defined above with respect to the first aspect of the present invention and will therefore not be repeated here.

[0063] The method according to this aspect of the present invention uses a heat-conducting fluid as defined in the first aspect of the present invention. Therefore, the preferred characteristics of this heat-conducting fluid have already been defined above with respect to the same components in the first aspect of the present invention, and are therefore not repeated here.

[0064] The preferred features of the indirect liquid cooling system and electronic components of the method according to the present invention have already been defined above with respect to the same components in the first aspect of the present invention, and will not be repeated here.

[0065] Preferably, the method for cooling an electronic component according to the present invention includes the step of conducting heat from the electronic component to the heat-conducting fluid.

[0066] In a preferred embodiment, if the indirect liquid cooling system in the method according to the present invention includes at least one thermally conductive element thermally coupled to the electronic component, the thermally conductive material is suitable for conducting heat from the electronic component to the thermally conductive fluid in the heat conduction step.

[0067] Thanks to the use of a heat-conducting fluid containing the diester defined above in an indirect liquid cooling system for cooling electronic components, thermal management of electronic components can be improved, and overheating phenomena that can lead to failure and irreparable damage can be avoided or significantly reduced, thereby enabling more efficient and safer use of electronic equipment on which electronic components are mounted.

[0068] Therefore, in a further embodiment, the present invention relates to electronic equipment including: At least one electronic component, and As defined in a first embodiment of the present invention, at least one indirect liquid cooling system suitable for cooling the electronic component, comprising at least one heat-conducting fluid comprising at least one diester of a C2-C9 aliphatic diol having at least one linear or branched C2-C7 aliphatic monocarboxylic acid.

[0069] The advantages and preferred features of the electronic devices according to the present invention have been disclosed in connection with the use and methods of other embodiments of the invention and will not be repeated herein.

[0070] Apparatus according to this aspect of the present invention uses a heat conduction fluid and an indirect liquid cooling system as defined in other aspects of the present invention. Therefore, preferred features of this heat conduction fluid and indirect liquid cooling system have already been defined above with respect to the same components in other aspects of the present invention and are therefore not repeated here.

[0071] Preferably, the electronic device according to this aspect of the present invention is selected from the group consisting of computers, servers, server farms, telecommunications centers, and data centers.

[0072] Preferably, in a device according to this aspect of the present invention, the electronic components of the device according to this aspect of the present invention are selected from the group consisting of a microprocessor, a semiconductor wafer, a power control semiconductor, an electrochemical cell, a distributed switchgear, a power transformer, a circuit board, a multichip module, a hard disk, a central processing unit, a packaged or unpackaged semiconductor device, a fuel cell, a laser, and a semiconductor integrated circuit.

[0073] More preferably, the electronic component is selected from the group consisting of a microprocessor, semiconductor wafer, power control semiconductor, circuit board, multichip module, hard disk, central processing unit, packaged or unpackaged semiconductor device, and semiconductor integrated circuit.

[0074] In a further embodiment, a heat-conducting fluid for cooling electronic components, A diester of a C2-C9 aliphatic diol and at least one linear or branched C2-C7 aliphatic monocarboxylic acid, At least one additive selected from the group consisting of antioxidants, pour point depressants, defoamers, corrosion inhibitors, viscosity modifiers, wear inhibitors and / or extreme pressure agents, friction modifiers, cleaning agents, dispersants, and mixtures thereof, This also relates to heat-conducting fluids, including those mentioned above.

[0075] The advantages and preferred characteristics of the heat-conducting fluid according to the present invention have been disclosed in connection with the use and methods of other embodiments of the invention and will not be repeated herein.

[0076] Therefore, the preferred features of the heat-conducting fluid according to this further aspect of the present invention have already been defined above with respect to the same components in the first aspect of the present invention, and will therefore not be repeated here.

[0077] Further features and advantages of the present invention should become clearer from the following description of some preferred embodiments, which are made below by the following non-limiting embodiments. [Examples]

[0078] <Example 1 - Preparation of neopentyl glycol dibarellat> 400 g (3.84 mol) of neopentyl glycol was placed in a multi-neck reaction flask equipped with an anchor stirrer, a Vigreux column, a condenser, and a distillate vessel. 980 g (9.6 mol) of valeric acid and 3 g of sodium hypophosphite monohydrate were added to the flask. Stirring was started, the system was purged with nitrogen, and the temperature was raised to the boiling point of the reaction mixture. The reaction was then continued until an amount of water equivalent to 100% of the stoichiometric amount for a 100% esterification yield had evaporated. Unreacted valeric acid was then removed by vacuum distillation until an acid value of less than 5 mg KOH / g was obtained. A stoichiometric excess of 4 wt% aqueous sodium hydroxide solution, sufficient to neutralize the acid value, was added to the esterification product, and the mixture was stirred for 30 minutes. The organic phase was then separated from the aqueous phase, washed with water, dried under vacuum, and filtered.

[0079] <Example 2-1,2 - Preparation of propanediyl divalerato> Example 1 was repeated using 292.18 g (3.84 mol) of 1,2-propanediol instead of 400 g of neopentyl glycol, and an acid value of 5 mg KOH / g was obtained at the end of valeric acid removal.

[0080] <Example 3-1,3-Preparation of propanediyl divalerato> Example 1 was repeated using 292.184 g (3.84 mol) of 1,3-propanediol instead of 400 g of neopentyl glycol, and an acid value of 5 mg KOH / g was obtained at the end of valeric acid removal.

[0081] <Example 4 - Preparation of 2-methyl-1,3-propanediyl divalerate> Example 1 was repeated using 346 g (3.84 mol) of 2-methyl-1,3-propanediol instead of 400 g of neopentyl glycol, and an acid value of 5 mg KOH / g was obtained at the end of valeric acid removal.

[0082] <Example 5 - Characterization of Diesters> The diesters obtained according to Examples 1-4 were characterized with respect to dynamic viscosity at -30°C in accordance with ISO 3219, flash point in accordance with ASTM D7094-04, pour point in accordance with ASTM D5950, and volume resistivity at 25°C in accordance with ASTM D1169. The results are reported in Table 1 below.

[0083] [Table 1]

[0084] <Example 6 - Characterization of Diesters> The diesters obtained according to Examples 1 to 4 were characterized with respect to thermal conductivity, thermal diffusivity, and specific heat.

[0085] The analysis was performed using the transient hot-wire method in accordance with ASTM D7896-19. The test apparatus used was Thermtest THW-L2, and the thermal conductivity and thermal diffusivity were measured at 40°C. The specific heat was calculated as follows: Cp at 40°C = thermal conductivity at 40°C / (thermal diffusivity at 40°C × density at 40°C).

[0086] The results are reported in Table 2 below.

[0087] [Table 2]

[0088] Based on a comprehensive characterization of the diesters in the above examples, developed and characterized for indirect cooling, it is clear that these fluids exhibit highly promising properties as an alternative solution to PFAS-based fluids. These diesters exhibit remarkable features such as low viscosity at ultra-low temperatures, ensuring efficient flow and circulation even in demanding cooling applications. In addition, their high flash points enhance safety measures and mitigate the potential risk of fire.

[0089] Furthermore, these diesters exhibit excellent volume resistivity and dielectric constant, ensuring optimal electrical insulation properties. In addition, their exceptional thermal conductivity and thermal capacity enable efficient heat dissipation, contributing to improved performance and reliability of electronic systems. Considering these advantageous properties, these diesters are a highly preferred alternative to PFAS fluids in the field of electronic cooling applications.

[0090] In summary, these diesters offer a more sustainable and environmentally friendly alternative to PFAS fluids, particularly in terms of greenhouse gas emissions. Their superior properties, coupled with reduced environmental impact, make them a highly preferred alternative for cooling electronic components.

Claims

1. At least one type of C ２ -C ９ an aliphatic diol and at least one linear or branched carbon ２ -C ７ Use of a thermal conductive fluid containing at least one diester with an aliphatic monocarboxylic acid for cooling electronic components in an indirect liquid cooling system.

2. In the heat-conducting fluid, the diester C ２ -C ９ The use according to claim 1, wherein the aliphatic diol is selected from the group consisting of ethylene glycol, 1,2-propanediol, 1,3-propanediol, 1,4-butanediol, 1,3-butanediol, diethylene glycol, triethylene glycol, dipropylene glycol, neopentyl glycol, 2-methyl-1,3-propanediol, 1,5-pentanediol, 1,6-hexanediol, 3-methyl-1,5-pentanediol, 2-butyl-2-ethyl-1,3-propanediol, 2,2,4-trimethyl-1,3-pentanediol, and mixtures thereof.

3. In the aforementioned heat-conducting fluid, the aliphatic diol of the diester is C ３ -C ６ The use according to claim 1 or 2, wherein the material is an aliphatic diol.

4. In the heat transfer fluid, the aliphatic diol of the diester is C ３ -C ５ The use according to claim 3, wherein the aliphatic diol is an aliphatic diol.

5. In the aforementioned heat-conducting fluid, the monocarboxylic acid of the diester is C ３ -C ５ The use according to any one of claims 1 to 4, wherein the aliphatic monocarboxylic acid.

6. In the aforementioned heat-conducting fluid, the monocarboxylic acid of the diester is C ５ -C ７ The use according to any one of claims 1 to 4, wherein the aliphatic monocarboxylic acid.

7. The use according to any one of claims 1 to 6, wherein the diester in the heat-conducting fluid is selected from the group consisting of neopentyl glycol divalerate, 1,2-propanediyl divalerate, 1,3-propanediyl divalerate, 2-methyl-1,3-propanediyl divalerate, and mixtures thereof.

8. The use according to any one of claims 1 to 7, wherein the indirect liquid cooling system includes at least one thermally conductive element thermally coupled to the electronic component, the thermal conductive element being suitable for conducting heat from the electronic component to the thermally conductive fluid.

9. The use according to claim 8, wherein the thermal conductive element is selected from the group consisting of a wall, a layer, a heat sink, a cold plate, a heat pipe, and a steam chamber.

10. The indirect liquid cooling system is used according to any one of claims 1 to 9, wherein it includes the following: A liquid cooling loop suitable for circulating the aforementioned heat-conducting fluid, A pump suitable for pumping the heat-conducting fluid into the entire liquid cooling loop, A heat exchanger suitable for cooling the aforementioned heat-conducting fluid, Optionally, a container suitable for containing the heat-conducting fluid.

11. The use according to any one of claims 1 to 10, wherein the electronic component is selected from the group consisting of a microprocessor, semiconductor wafer, power control semiconductor, electrochemical cell, electrically distributed switchgear, power transformer, circuit board, multichip module, hard disk, central processing unit, packaged or unpackaged semiconductor device, fuel cell, laser, and semiconductor integrated circuit.

12. The use according to any one of claims 1 to 11, wherein the electronic component is mounted on an electronic device.

13. The use according to claim 12, wherein the electronic device is selected from the group consisting of a computer, a server, a server farm, a communication center, and a data center.

14. A method for cooling electronic components using an indirect liquid cooling system, wherein the liquid cooling system comprises at least one type C ２ -C ９ Aliphatic diol and at least one linear or branched carbon atom ２ -C ７ A method comprising a thermal conductive fluid containing at least one diester with an aliphatic monocarboxylic acid.

15. The method according to claim 14, wherein the method includes the step of conducting heat from the electronic component to the heat-conducting fluid.

16. The method according to claim 14 or 15, wherein the heat conducting fluid is the heat conducting fluid described in any one of claims 1 to 7.

17. The method according to any one of claims 14 to 16, wherein the indirect liquid cooling system is the indirect liquid cooling system according to any one of claims 8 to 10.

18. The method according to claim 17, wherein the indirect liquid cooling system includes at least one thermally conductive element thermally coupled to the electronic component, and is suitable for conducting heat from the electronic component to the thermally conductive fluid in the step of conducting heat through the thermally conductive material.

19. The method according to any one of claims 14 to 18, wherein the electronic component is the electronic component described in any one of claims 11 to 12.

20. Electronic devices, including the following: At least one electronic component, C ２ -C ９ Aliphatic diol and at least one linear or branched carbon atom ２ -C ７ an indirect liquid cooling system suitable for cooling the electronic component, comprising at least one thermal conductive fluid comprising at least one diester of an aliphatic monocarboxylic acid.

21. The electronic device according to claim 20, wherein the heat-conducting fluid is the heat-conducting fluid described in any one of claims 1 to 7.

22. The electronic device according to claim 20 or 21, wherein the indirect liquid cooling system is the indirect liquid cooling system according to any one of claims 8 to 10.

23. The electronic device according to any one of claims 20 to 22, wherein the electronic device is selected from the group consisting of a computer, a server, a server farm, a communication center, and a data center.

24. The electronic device according to any one of claims 20 to 23, wherein the electronic component is an electronic component selected from the group consisting of a microprocessor, a semiconductor wafer, a power control semiconductor, an electrochemical cell, an electrically distributed switchgear, a power transformer, a circuit board, a multi-chip module, a hard disk, a central processing unit, a packaged or unpackaged semiconductor device, a fuel cell, a laser, and a semiconductor integrated circuit.

25. C ２ -C ９ Aliphatic diol and at least one linear or branched carbon ２ -C ７ A diester of at least one aliphatic monocarboxylic acid, At least one additive selected from the group consisting of antioxidants, pour point depressants, defoamers, corrosion inhibitors, viscosity modifiers, wear-resistant and / or extreme pressure additives, friction modifiers, cleaning agents, dispersants, and mixtures thereof, A heat-conducting fluid for cooling electronic components, including [specific component name].

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