Monitoring of dissolved contaminants in immersion cooling working fluid

Abstract

The absorbance of a portion of the working fluid in the immersion cooling system to ultraviolet light at a first predetermined wavelength is measured. Since the working fluid is composed of a first dielectric compound that is transparent to the first predetermined wavelength λ1, and a first compound containing contaminants is dissolved in the working fluid but is opaque to ultraviolet light at λ1, the measured absorbance can be used to calculate a first concentration value representing the concentration of the first compound dissolved in the working fluid.

Description

Technical Field

[0001] This invention relates to the monitoring of contaminants dissolved in the working fluid of an immersion cooling device. Background Technology

[0002] Electronic components in systems such as computer servers perform significant workloads and generate substantial amounts of heat during their operation, which must be removed to prevent overheating. Partly due to the heat generated, these electronic components are typically configured in a stacked structure and cooled by large internal cooling fans and heat sinks. As the size and density of these systems increase, the thermal challenges become even greater, eventually exceeding the capabilities of air cooling systems. Immersion cooling has emerged as an alternative to forced air cooling systems, and it may become more economical as the energy density of the cooled electronic components increases.

[0003] Battery temperature control is crucial for the safe and efficient operation of electric vehicles. Battery cells can be cooled under load or while charging to achieve more efficient operation. Cooling is particularly important during charging to prevent thermal runaway. Since the relationship between battery performance and ambient temperature is known, battery cells can be heated to improve operating efficiency during operation at relatively cool ambient temperatures. Whether heating or cooling, thermal management is typically performed using a warm / cold plate at the bottom of the battery pack or through water-based coolant channels between the battery cells. Immersion cooling, on the other hand, has emerged as a viable alternative to this conventional heat transfer method.

[0004] Immersion cooling of electronic components can be performed in a single-phase mode, where the temperature of the heat transfer fluid (also known as the working fluid) is maintained below its boiling point. In single-phase immersion cooling, the heat removed from the electronic component is in the form of the sensible heat of the heat transfer fluid. Immersion cooling of electronic components can also be performed in a two-phase mode, where the temperature of the heat transfer fluid is maintained near its boiling point, and the heat transfer fluid boils on the surface of the electronic component or through a heat sink or heat transfer surface attached thereto. In two-phase immersion cooling, the heat removed from the electronic component is in the form of the latent heat of the heat transfer fluid.

[0005] Whether the electronic components are computer servers, batteries, or other devices, and regardless of whether the immersion cooling is single-phase or two-phase, temperature control is an important consideration for a variety of reasons.

[0006] Another consideration for immersion cooling is the contaminants in the heat transfer fluid.

[0007] Contamination and material compatibility between the heat transfer fluid and the electronic components are important considerations, particularly in two-phase immersion systems where components are in direct contact with the heat transfer fluid. In such systems, plasticizers such as di(2-ethylhexyl) phthalate (also known as dioctyl phthalate or DOP), di(2-ethylhexyl) terephthalate (also known as dioctyl terephthalate, or DOTP), diisodecyl phthalate (DIDP), and tri(2-ethylhexyl) trimellitate (also known as trioctyl trimellitate or TOTM) are naturally extracted (or diffused) from components such as cables, elastomers, and plastics by the immersion fluid itself. When in solution, plasticizers can be detrimental to the dielectric properties of the immersion fluid. When plasticizer concentrations exceed their solubility limits in dielectric fluids, excessive plasticizers can deposit on tanks or server parts because their boiling points are higher than those of the heat transfer fluid. More specifically, these plasticizers can be deposited by distillation in a hot surface with active boiling. This can be particularly problematic for boilerplates (heat sinks with porous heat transfer surfaces located above CPUs and GPUs), where plasticizers can deposit and fill bubble nucleation cavities. This reduction in bubble nucleation sites leads to decreased heat transfer performance and, consequently, increased internal chip (“junction”) temperatures. Higher junction temperatures reduce chip lifespan and, when junction temperatures approach the maximum values ​​established by chip manufacturers, cause premature “throttling” (reducing processing speed) of the chip to decrease power dissipation. Depending on the heat transfer fluid used, the levels of contaminants that can cause hardware and device problems can be very low, as low as less than 100 ppm, 10 ppm, or even lower. The most common contaminants identified in these systems are plasticizers, typically phthalates or terephthalates, which are usually extracted from plastics and elastomers present in hardware such as cables and seals.

[0008] While the amount of contaminants can be reduced through adsorption filtration, adsorption filters require periodic replacement and / or the heat transfer fluid will need to be replaced periodically because once the filter becomes saturated, it loses its ability to remove contaminants from the heat transfer fluid. If a saturated filter is exposed to a heat transfer fluid carrying an additional amount of contaminants, the filter will experience what is known as breakthrough, and the contaminant level may continue to rise by continuously extracting contaminant material from the electronic components. Therefore, monitoring contaminant levels is valuable so that replacement can be initiated before breakthrough occurs.

[0009] WO 2022 / 058915 A1 discloses the use of a capacitive sensor to sense contaminant levels in the working fluid of a two-phase immersion cooling system. Such a capacitive sensor is relatively insensitive to very low levels of contaminants. However, the accuracy of contaminant level measurements using the sensor disclosed in WO 2022 / 058915 A1 is highly dependent on the total surface area of ​​the sensor used. Those skilled in the art will recognize that the total surface area of ​​the sensor includes both the horizontal and vertical portions of the surface being measured. While the vertical portion of the surface area (approximated by measuring surface roughness) may be very small compared to the horizontal portion, accurate measurement of the total surface area remains important. Unless such a sensor takes into account accurate measurement of the entire surface area, using such a sensor to measure very low levels of contaminants may provide unsatisfactory levels of accuracy. Those skilled in the art will recognize that unsatisfactory levels of accuracy may lead to undetected process problems.

[0010] WO 2022 / 058915 A1 attempts to overcome the insensitivity problem at low contaminant levels by concentrating contaminants through localized boiling or distillation of the working fluid. However, this solution leads to further complexity and inaccuracy in contaminant level measurement.

[0011] US 2022 / 0341860 A1 proposes monitoring the temperature difference between the working fluid and the surface of a cooled component. This is based on the observation that if contaminant levels rise too high, contaminant deposition on the component surface may occur, and the heat transfer rate from the component to the working fluid decreases accordingly, then the temperature difference will increase. US 2022 / 0341860 A1 uses the measured temperature difference as an alternative for predicting when such excessive contaminant deposition will occur. However, it does not provide guidance on whether their contamination measurement techniques are reliably applicable to different types of working fluids and / or different types of contaminants. Furthermore, the detection techniques disclosed in US 2022 / 0341860 A1 only detect contamination problems when solid residues have formed, and cannot detect contamination problems where no solid residues have formed.

[0012] US 2022 / 0252523 A1 discloses a specific method for detecting the presence of solid or oily contaminant residues on the surface of electronic components within a two-phase immersion cooling bath, utilizing the detection of reflected light from the bath's surface. However, US 2022 / 0252523 A1 only detects contamination problems when solid or oily residues have formed on the surface, and cannot detect contamination problems when no solid or oily residues have formed on the monitored surface.

[0013] Given the aforementioned drawbacks of conventional pollutant monitoring techniques related to immersion cooling, there is a need for improved methods and systems for pollutant monitoring. Summary of the Invention

[0014] A method for monitoring contaminants dissolved in the working fluid of an immersion cooling device is disclosed, comprising the following steps: Providing an immersion cooling device including a housing, the inner surface of which defines a sealable internal cavity containing an article to be cooled, at least partially immersed in the liquid phase of the working fluid, wherein the working fluid includes a first dielectric compound, the article to be cooled includes a first compound soluble in the first dielectric compound, and the working fluid includes a certain amount of the first compound dissolved therein. Measuring the absorbance of a portion of the working fluid to ultraviolet light at a predetermined wavelength λ1 using an absorbance-based spectrophotometer, wherein the first dielectric compound is transparent to ultraviolet light at λ1, and the first compound is opaque to ultraviolet light at λ1. Using the absorbance-based spectrophotometer, calculating a first concentration representing the concentration of the first compound dissolved in the working fluid based on the measured absorbance and a standard absorbance value stored in the memory of the absorbance-based spectrophotometer, the standard absorbance value corresponding to the absorbance at λ1 of a standard solution comprising a known concentration of the first compound in the working fluid.

[0015] A method for monitoring contaminants dissolved in the working fluid of an immersion cooling device is also disclosed, comprising the following steps: An immersion cooling device including a housing is provided, the inner surface of which defines a sealable internal cavity containing an article to be cooled, at least partially immersed in the liquid phase of the working fluid, wherein the working fluid includes a first dielectric compound, the article to be cooled includes a first compound soluble in the first dielectric compound, and the working fluid includes a certain amount of the first compound dissolved therein. The absorbance of a portion of the working fluid to ultraviolet light at a first predetermined wavelength is measured using an absorbance-based spectrophotometer, wherein the first dielectric compound is transparent to ultraviolet light at the first predetermined wavelength, and the first compound is opaque to ultraviolet light at the first predetermined wavelength. Using the absorbance-based spectrophotometer, a first concentration representing the concentration of the first compound dissolved in the working fluid is calculated based on the measured absorbance at the first predetermined wavelength and a standard absorbance value stored in the memory of the absorbance-based spectrophotometer, the standard absorbance value corresponding to the absorbance of a standard solution comprising a known concentration of the first compound in the working fluid to ultraviolet light at the first predetermined wavelength. After the step of calculating the first concentration using an absorbance-based spectrophotometer, a period of time is allowed during which a certain amount of the first compound dissolves in the working fluid, such that the concentration of the first compound in the working fluid increases compared to the concentration of the first compound in the working fluid before the step of calculating the first concentration using an absorbance-based spectrophotometer. The absorbance of a portion of the working fluid to ultraviolet light at a second predetermined wavelength is measured using an absorbance-based spectrophotometer, wherein the first dielectric compound is transparent to ultraviolet light at the second predetermined wavelength, and the first compound is opaque to ultraviolet light at the second predetermined wavelength. After step (e), a second concentration representing the concentration of the first compound dissolved in the working fluid is calculated using an absorbance-based spectrophotometer, based on the measured absorbance at the second predetermined wavelength and a standard absorbance value.

[0016] A method for monitoring contaminants dissolved in the working fluid of an immersion cooling device is also disclosed, comprising the following steps: Cooling an article to be cooled by direct heat exchange with the liquid working fluid in the immersion cooling device, the article to be cooled comprising a first compound soluble in a first dielectric compound, the working fluid comprising a certain amount of the first compound dissolved therein; removing a certain amount of the dissolved first compound from the working fluid using an adsorption filter comprising an adsorbent material adapted and configured to adsorb the first compound; measuring the absorbance of a portion of the working fluid to ultraviolet light at a predetermined wavelength λ using an absorbance-based spectrophotometer to generate an initial absorbance value, wherein the first dielectric compound is transparent to ultraviolet light at a first predetermined wavelength, and the first compound is opaque to ultraviolet light at the first predetermined wavelength; calculating an initial concentration value representing the concentration of the first compound dissolved in the working fluid based on the initial absorbance value and a standard absorbance value stored in the memory of the absorbance-based spectrophotometer, the standard absorbance value corresponding to the absorbance of a standard solution comprising a known concentration of the first compound in the working fluid to ultraviolet light at a first predetermined wavelength. After the step of calculating the first concentration using an absorbance-based spectrophotometer, a period of time is allowed during which a certain amount of the first compound is dissolved in the working fluid, such that the concentration of the first compound in the working fluid increases compared to the concentration of the first compound in the working fluid before the step of calculating the first concentration using the absorbance-based spectrophotometer. After a period of time, the absorbance of ultraviolet light is measured again using the absorbance-based spectrophotometer to generate a subsequent absorbance value. Using the absorbance-based spectrophotometer, based on the subsequent absorbance value and a stored standard absorbance value, a subsequent concentration value representing the concentration of the first compound dissolved in the working fluid is calculated, and the subsequent concentration is higher than a predetermined concentration value. In response to the calculation that the subsequent concentration value is higher than the predetermined concentration value: 1) the adsorbent material is replaced, 2) at least a portion of the working fluid is replaced with a certain amount of dielectric compound that does not have a detectable amount of the first compound, or 3) at least a portion of the working fluid is purified to remove a certain amount of the first compound therefrom.

[0017] A method for two-phase immersion cooling of an article to be cooled using a working fluid with monitored contamination levels is also disclosed, comprising the following steps: The article to be cooled is cooled by direct heat exchange with a liquid working fluid in an immersion cooling apparatus. The article to be cooled includes a first compound soluble in a first dielectric compound. The working fluid includes a certain amount of the first compound dissolved therein. Contact between the article to be cooled and the working fluid causes the working fluid to boil and generate vapor in a headspace above the liquid working fluid. The vapor is condensed using a condenser disposed in the headspace. A certain amount of the dissolved first compound is removed from the working fluid using an adsorption filter, the adsorption filter including an adsorbent material suitable for and configured to adsorb the first compound. The absorbance of a portion of the working fluid to ultraviolet light at a predetermined wavelength λ in the range of 260 nm to 290 nm is measured using an absorbance-based spectrophotometer to generate an initial absorbance value, wherein the first dielectric compound is transparent to ultraviolet light at the first predetermined wavelength, and the first compound is opaque to ultraviolet light at the first predetermined wavelength. Using an absorbance-based spectrophotometer, an initial concentration value representing the concentration of a first compound dissolved in the working fluid is calculated based on the initial absorbance value and a standard absorbance value stored in the memory of the absorbance-based spectrophotometer. The standard absorbance value corresponds to the absorbance of a standard solution of the first compound at a known concentration in the working fluid to ultraviolet light at a first predetermined wavelength. After the step of calculating the initial concentration value using the absorbance-based spectrophotometer, a period of time is allowed to pass, during which a certain amount of the first compound is dissolved in the working fluid, such that the concentration of the first compound in the working fluid increases compared to the concentration of the first compound present in the working fluid before the step of calculating the initial concentration value using the absorbance-based spectrophotometer. The step of calculating the initial concentration value using the absorbance-based spectrophotometer is repeated to generate subsequent absorbance values. Using the absorbance-based spectrophotometer, a subsequent concentration value representing the concentration of the first compound dissolved in the working fluid, which is higher than the predetermined concentration value, is calculated based on the subsequent absorbance value and the stored standard absorbance value. In response to a subsequent concentration value higher than the predetermined concentration value: 1) replace the adsorbent material, 2) replace at least a portion of the working fluid with a dielectric compound having a detectable amount of the first compound, or 3) purify the working fluid to remove a certain amount of the first compound.

[0018] A system for immersion cooling of an article to be cooled is disclosed, comprising: an immersion cooling device including a housing and an adsorption filter, the inner surface of the housing defining a sealable internal cavity; the adsorption filter including an adsorbent material adapted and configured to adsorb a first compound selected from: di(2-ethylhexyl) phthalate, di(2-ethylhexyl) terephthalate, diisodecyl phthalate, and tri(2-ethylhexyl) trimellitate; the article to be cooled, disposed within the cavity at a position adapted and configured to be at least partially immersed in the liquid phase of a working fluid; and based on... An absorbance-based spectrophotometer, wherein the absorbance-based spectrophotometer is adapted and configured to measure the absorbance of a portion of a working fluid to ultraviolet light at a first predetermined wavelength, and to calculate the concentration of a first compound in the working fluid to ultraviolet light at the first predetermined wavelength based on the measured absorbance and a standard absorbance value of a standard solution comprising a first compound at a known concentration in the working fluid, the standard absorbance value being stored in a memory of the absorbance-based spectrophotometer, and the absorbance-based spectrophotometer displaying information indicating that the adsorbent material needs to be replaced or at least a portion of the working fluid needs to be replaced.

[0019] Any one or more of the foregoing methods or systems may include one or more of the following aspects:

[0020] - The immersion cooling device is a single-phase cooling device; the item to be cooled is completely immersed in the working fluid and maintained at an operating temperature below the boiling temperature of the first dielectric compound; the immersion cooling device also includes an inlet and an outlet, the inlet being adapted and configured to receive the working fluid cooled at a heat transfer device and entering the cavity, the outlet being adapted and configured to guide the working fluid from the cavity to the heat transfer device, the heat transfer device being adapted and configured to actively or passively remove heat from the working fluid; and pumping the working fluid from the outlet through the heat transfer device to the inlet; and removing heat from the heat transfer device to cool the working fluid therein.

[0021] - The immersion cooling device is a two-phase cooling device; the operating temperature of the article to be cooled is higher than the boiling point of the first dielectric compound, and the first dielectric compound is boiled at one or more portions of the article to be cooled, thereby generating vapor in the top space above the liquid phase of the working fluid; the vapor is condensed at a condenser disposed in the top space; and the heat transfer fluid is pumped through the condenser, in which the heat transfer fluid is cooled to a temperature below the boiling point of the first dielectric compound by a heat transfer device adapted to actively or passively remove heat from the heat transfer fluid.

[0022] The immersion cooling device also includes an adsorption filter having an inlet and an outlet in fluid communication with the working fluid and including an adsorption medium adapted and configured to adsorb the first compound.

[0023] - Replace the adsorption medium when the calculated concentration is higher than the predetermined concentration.

[0024] - The predetermined concentration is selected from: 200ppm, 100ppm, 50ppm, 25ppm, 10ppm and 5ppm.

[0025] - Replace at least a portion of the working fluid when the calculated concentration is higher than the predetermined concentration.

[0026] - The article to be cooled also includes a second compound soluble in the first dielectric compound; the working fluid includes a certain amount of the second compound dissolved therein; the absorbance of a portion of the working fluid to ultraviolet light at a predetermined wavelength λ2 is measured using an absorbance-based spectrophotometer, wherein the first dielectric compound is transparent to ultraviolet light at λ2 and the second compound is opaque to ultraviolet light at λ2; a second concentration representing the concentration of the second compound dissolved in the working fluid is calculated using an absorbance-based spectrophotometer based on the measured absorbance and a standard absorbance value.

[0027] The immersion cooling device also includes an adsorption filter having an inlet and an outlet in fluid communication with the working fluid and including an adsorption medium adapted and configured to adsorb the first compound.

[0028] - Replace the adsorption medium when the first or second calculated concentration is higher than the predetermined concentration.

[0029] - The predetermined concentration is selected from: 200ppm, 150ppm, 100ppm, 50ppm, 25ppm, 10ppm and 5ppm.

[0030] - Replace at least a portion of the working fluid when the first or second calculated concentration is higher than the predetermined concentration.

[0031] - When the first calculated concentration or the second calculated concentration is higher than the predetermined concentration, at least a portion of the working fluid is purified to remove a certain amount of the first compound.

[0032] - The first dielectric compound is selected from: E-1,1,1,2,2,5,5,6,6,6-decafluoro-3-hexene (HFO-153-10mczz-E), Z-1,1,1,2,2,5,5,6,6,6-decafluoro-3-hexene (HFO-153-10mczz-Z), E-1,1,1,4,5,5,5-heptafluoro-4-trifluoromethyl-2-pentene (HFO-153-10mzzy-E), Z-1,1,1,4,5,5 5-Hepano-4-trifluoromethyl-2-pentene (HFO-153-10mzzy-Z), E-1,1,1,4,4,4-hexafluoro-2-butene (HFO-1336mzz-E), Z-1,1,1,4,4,4-hexafluoro-2-butene (HFO-1336mzz-Z), hexafluoropropylene dimer, E-perfluoro(4-methyl-2-pentene), perfluoro-2-methyl-2-pentene, Z-perfluoro(4-methyl-2-pentene), and hexafluoropropylene trimer.

[0033] The working fluid also includes a second dielectric compound, which is different from the first dielectric compound, and the first dielectric compound is present in the working fluid at a concentration of at least 99% by weight.

[0034] The working fluid also includes a second dielectric compound, which is different from the first dielectric compound, and the first dielectric compound is present in the working fluid at a concentration of at least 99.5% by weight.

[0035] - The second dielectric compound is selected from: E-1,1,1,2,2,5,5,6,6,6-decafluoro-3-hexene (HFO-153-10mczz-E); Z-1,1,1,2,2,5,5,6,6,6-decafluoro-3-hexene (HFO-153-10mczz-Z), E-1,1,1,4,5,5,5-heptafluoro-4-trifluoromethyl-2-pentene (HFO-153-10mzzy-E); Z-1,1,1,4,5,5,5-heptafluoro-4-trifluoromethyl-2-pentene (HFO-153-10mzzy-Z), E-1,1,1, 4,4,4-Hexafluoro-2-butene (HFO-1336mzz-E), Z-1,1,1,4,4,4-Hexafluoro-2-butene (HFO-1336mzz-Z); 1,1,1,2,2,3,3,4,4,5,5,6,6,6-Tetradecoxane; hexafluoropropylene dimer; E-perfluoro(4-methyl-2-pentene); perfluoro-2-methyl-2-pentene, Z-perfluoro(4-methyl-2-pentene); hexafluoropropylene trimer; ethyl nonafluoroisobutyl ether; ethyl nonafluorobutyl ether; and 1,1,1,2,2,4,5,5,5-nonafluoro-4-(trifluoromethyl)-3-pentanone.

[0036] - The first compound is phthalate or terephthalate.

[0037] - The first compound is selected from: di(2-ethylhexyl) phthalate, di(2-ethylhexyl) terephthalate, diisodecyl phthalate and tri(2-ethylhexyl) trimellitate.

[0038] - The first predetermined wavelength is in the range of 210nm to 305nm.

[0039] - The first predetermined wavelength is in the range of 240nm to 295nm.

[0040] - The first predetermined wavelength is in the range of 900nm to 2500nm.

[0041] - The first predetermined wavelength, expressed in wavenumber, is at 500cm. -1 Up to 4000cm -1 Within the range.

[0042] - The items to be cooled are selected from the following electronic components: high-capacity energy storage devices, computer servers, data center servers, GPUs, CPUs, solar photovoltaics, batteries, insulated gate bipolar transistor (IGBT) devices, telecommunications infrastructure, military electronic devices, televisions, mobile phones, monitors, drones, automotive batteries, power systems for electric vehicles, power electronic devices, avionics equipment, power equipment, power transformers, and displays.

[0043] - The immersion cooling device is a single-phase immersion cooling device, and the immersion cooling device further includes a heat transfer device recirculation system adapted and configured to receive working fluid at a first temperature from the cavity, introduce the working fluid into the heat transfer device, and return the working fluid to the cavity, wherein the working fluid is cooled to a second temperature below the first temperature in the heat transfer device.

[0044] - The immersion cooling device is a two-phase immersion cooling device, and the immersion cooling device further includes: a fluid condenser disposed within the cavity at a location adapted and configured to condense vapor generated by boiling of the working fluid at the surface of the item to be cooled; and a recirculation system including an inlet in fluid communication with the interior of the condenser, an outlet in fluid communication with the interior of the condenser, a pump in fluid communication between the inlet and the outlet, and a heat transfer device in fluid communication between the inlet and the outlet, the pump being adapted and configured to recirculate the coolant from the interior of the condenser through the heat transfer device and return it to the interior of the condenser, the heat transfer device being adapted and configured to cool the coolant thereon. Attached Figure Description

[0045] Figure 1 This is a schematic diagram of the immersion cooling device used in the present invention.

[0046] Figure 2 This is a schematic diagram of an embodiment of the single-phase immersion cooling system used in the present invention.

[0047] Figure 3 This is a schematic diagram of a single-phase immersion cooling system for an implementation scheme including an absorbance-type spectrophotometer for pollutant monitoring.

[0048] Figure 4 This is a schematic diagram of a single-phase immersion cooling system, which includes another embodiment of an absorbance-type spectrophotometer for pollutant monitoring.

[0049] Figure 5 This is a schematic diagram of an embodiment of the two-phase immersion cooling system used in the present invention.

[0050] Figure 6 This is a schematic diagram of a two-phase immersion cooling system for an implementation scheme including an absorbance-type spectrophotometer for pollutant monitoring.

[0051] Figure 7 This is a schematic diagram of a two-phase immersion cooling system, which is an alternative embodiment of an absorbance-type spectrophotometer for pollutant monitoring.

[0052] Figure 8 The calibration curves of dioctyl terephthalate (DOP) dissolved in HFO-153-10mczz-E at 293 nm and 282 nm are shown.

[0053] Figure 9 This is the calibration curve of DOP dissolved in HFO-153-10-mczz-E at 273nm.

[0054] Figure 10 This is the calibration curve of trioctyl terephthalate (TOTM) dissolved in HFO-153-10-mczz-E at 273 nm.

[0055] Figure 11 This is a graph showing the UV-Vis spectra of three different concentrations of DOTP in HFO-153-10mczz-E.

[0056] Figure 12 This is a graph of the UV-Vis spectra of pure HFO-153-10-mczz-E and HFO-153-10-mczz-E that has been used in the impregnation tank and contaminated with plasticizer.

[0057] Figure 13This is a graph showing the UV-Vis spectra of HFO-135-10mczz-E with and without 100ppm (w / w) DOTP, compared to Novec 649 with and without 100ppm (m / m) DOTP.

[0058] Figure 14 This is a graph showing the UV-Vis spectra of three different HFOs and the same HFO containing 100 ppm DOTP (w / w). Detailed Implementation

[0059] This invention uses spectrophotometry to monitor the level of contaminants dissolved in the working fluid of an immersion cooling device. More specifically, the absorbance of a portion of the working fluid to ultraviolet light at a first predetermined wavelength is measured. Since the working fluid is composed of a first dielectric compound that is transparent to the first predetermined wavelength λ1, and the first compound of the contaminant is dissolved in the working fluid but is opaque to ultraviolet light at λ1, the measured absorbance can be used to calculate a first concentration value representing the concentration of the first compound dissolved in the working fluid. This is accomplished by referring to a stored absorbance value corresponding to the absorbance of one or more standard solutions of the first compound, comprising a known concentration, of ultraviolet light at λ1 in the working fluid.

[0060] Items to be cooled

[0061] The item to be cooled is an electronic component. Electronic components are devices that are supplied with current, currently being supplied with current, or intermittently supplied with current while being cooled in an immersion cooling device. In some areas, electronic components are selected from: high-capacity energy storage devices, computer servers, data center servers, solar photovoltaic systems, batteries, insulated-gate bipolar transistor (IGBT) devices, telecommunications infrastructure, military electronics, televisions, mobile phones, monitors, drones, automotive batteries, power systems for electric vehicles, power electronics, avionics equipment, electrical equipment, power transformers, and displays.

[0062] working fluid

[0063] When the immersion cooling device is put into use, the working fluid is an industrially pure first dielectric compound. "Industrially pure" means that the working fluid contains at least 98 wt% of the first dielectric compound, and in some respects at least 99 wt% of the first dielectric compound. After the article to be cooled is exposed to the working fluid, a certain amount of the first compound is extracted from and dissolved in the first dielectric compound. Therefore, during operation of the invention, the working fluid may include a first compound at a concentration of up to 200 ppm, in some respects up to 150 ppm, in some respects 100 ppm, in some respects up to 50 ppm, in some respects up to 25 ppm, and in some respects up to 10 ppm. Additionally, a certain amount of air impurities and moisture may dissolve in the working fluid.

[0064] The first dielectric compound is transparent to ultraviolet light at a first predetermined wavelength λ1. In some aspects, the first dielectric compound is selected from: E-1,1,1,2,2,5,5,6,6,6-decafluoro-3-hexene (HFO-153-10mczz-E), E-1,1,1,4,5,5,5-heptafluoro-4-trifluoromethyl-2-pentene (HFO-153-10mzzy-E), and Z-1,1,1,4,4,4-hexafluoro-2-butene (HFO-1336mzz-Z). Each of the above compounds is transparent to ultraviolet light in the 260-290 nm region.

[0065] In some aspects, the working fluid may also include a second dielectric compound or even another dielectric compound different from the first dielectric compound, in which case the first dielectric compound is present in the working fluid at a concentration of at least 99% by weight. In some aspects, the second dielectric compound is selected from: E-1,1,1,2,2,5,5,6,6,6-decafluoro-3-hexene (HFO-153-10mczz-E); E-1,1,1,4,5,5,5-heptafluoro-4-trifluoromethyl-2-pentene (HFO-153-10mzzy-E); Z-1,1,1,4,4,4-hexafluoro-2-butene (HFO-1336mzz); and one or more mixtures thereof. In some aspects, the second dielectric compound is alternatively selected from: 1,1,1,2,2,3,3,4,4,5,5,6,6,6-tetradecoxane; ethyl nonafluoroisobutyl ether; ethyl nonafluorobutyl ether; 1,1,1,2,2,4,5,5,5-nonafluoro-4-(trifluoromethyl)-3-pentanone; and one or more mixtures thereof. As will be described in more detail below, although each of these alternative types of dielectric compounds may be opaque to ultraviolet light at λ, they may all be included in the working fluid in an amount that does not substantially interfere with the calculation of the concentration of the first compound dissolved in the working fluid. In some aspects, the working fluid comprises at least 99.5 wt% of the first dielectric compound and at most 0.5 wt% of the second dielectric compound.

[0066] pollutants

[0067] After commissioning the immersion cooling device and after the article to be cooled has been exposed to the working fluid, the working fluid may include one or more contaminants, including the first compound, as well as air and moisture potentially dissolved in the fluid. As described above, the first compound is soluble in the working fluid. In some aspects, the first compound is soluble in a first dielectric compound. In some aspects, one or more sub-components of the article to be cooled are made of an organic compound. In some aspects, one or more sub-components of the article to be cooled are made of a thermoplastic, thermosetting, elastomer, rubber, or a combination of one or more of the foregoing. In some aspects, the sub-component is a cable or a seal. In some aspects, the first compound is a plasticizer.

[0068] In some aspects, the first compound is a phthalate or a terephthalate. In some aspects, the first compound is selected from: di(2-ethylhexyl) phthalate (also known as dioctyl phthalate or DOP), di(2-ethylhexyl) terephthalate (also known as dioctyl terephthalate, or DOTP), diisodecyl phthalate (DIDP), and tri(2-ethylhexyl) trimellitate (also known as trioctyl trimellitate or TOTM).

[0069] In some respects, the concentration of the first compound dissolved in the working fluid is greater than zero and is: 200 ppm or less, 190 ppm or less, 180 ppm or less, 170 ppm or less, 160 ppm or less, 150 ppm or less, 140 ppm or less, 130 ppm or less, 120 ppm or less, 110 ppm or less, 100 ppm or less, 90 ppm or less, 80 ppm or less, 75 ppm or less, 70 ppm or less, 60 ppm or less, 50 ppm or less, 40 ppm or less, 30 ppm or less, 25 ppm or less, 20 ppm or less, 15 ppm or less, 10 ppm or less, 7 ppm or less, or 5 ppm or less.

[0070] Absorbance-type spectrophotometric analysis

[0071] During the use of the absorbance-type spectrophotometric technique of the present invention, incident light in the ultraviolet frequency range provided by a radiation source is guided through a transparent (at the wavelength of interest) detection cell comprising a portion of a working fluid. Because the working fluid includes a certain amount of a first compound dissolved therein, and the first compound absorbs ultraviolet light at λ1, the intensity of the incident light at λ1 attenuates in a manner described by Beer-Lambert's law. After passing through the working fluid and the transparent detection cell, the intensity of unabsorbed light is detected and quantified at a radiation detector and / or transducer that converts radiant energy into an electrical signal. In some aspects, the radiation detector and / or transducer is selected from electrically coupled device type (CCD) detectors, photodiodes, silicon photodiodes, photodiode arrays, photomultiplier tubes, and phototubes. Notably, the radiation detector and / or transducer does not detect and quantify the intensity of unabsorbed light after reflection from a surface as done in the contaminant monitoring technique of US2022 / 0252523 A1. The signal from the radiation detector and / or transducer is received by a data acquisition and processing unit. In some respects, the data acquisition and processing unit is a microprocessor or computer.

[0072] The unit functions of the aforementioned absorbance-based spectrophotometric analysis techniques can be performed using absorbance-based spectrophotometric apparatuses. Absorbance-based spectrophotometric apparatuses include a radiation source, a radiation detector and / or transducer, and a data acquisition and processing unit. In some aspects, absorbance-based spectrophotometric apparatuses include in-situ probes (including a radiation source and a radiation detector and / or transducer) and a data acquisition and processing unit. In other aspects, absorbance-based spectrophotometric apparatuses include a pick-up tube and a separate spectrophotometer (including a radiation source, a radiation detector and / or transducer, and a data acquisition and processing unit) that receives the sample with a working fluid via the pick-up tube and a pump.

[0073] In some aspects, the data acquisition and processing unit is adapted and configured to output signals, such as audible or visual warning signals for the operator, or in the form of information displayed by a computer monitor. In some aspects, the signal may represent a calculated concentration of the first compound. In some aspects, the signal may indicate a recommendation to replace the adsorption medium of any pre-set filters within the immersion cooling apparatus, the adsorption medium being used to adsorb contaminants (such as the first compound). In some aspects, the signal may indicate a recommendation to replace some or all of the working fluid with an industrially pure first dielectric compound. In some aspects, the signal may indicate a recommendation to purify some or all of the working fluid to remove a certain amount of the first compound. In some aspects, purification may include removing a certain amount or all of the working fluid and removing a certain amount of the first compound using conventional purification techniques, and then placing the thus purified working fluid into the cavity of the immersion cooling apparatus. In some respects, the signal may indicate that the calculated concentration of the first compound is within one of two or more individual concentration ranges covering the overall range from 0 ppm to an upper limit (e.g., 200 ppm), for example: i) 0-10 ppm, ii) 10-50 ppm, iii) 50-100 ppm, 100-150 ppm and / or 150-200 ppm.

[0074] Before, during, and / or after implementing the contaminant monitoring and / or immersion cooling (using contaminant monitoring) technology of the present invention, those skilled in the art will recognize that the absorbance-based spectrophotometer can be calibrated so that the data acquisition and processing unit can be used to calculate the concentration of the first compound dissolved in the working fluid by referring to one or more stored values ​​corresponding to the absorbance, by referring to a reference solution comprising a first compound of different known concentrations.

[0075] The first predetermined wavelength λ1 of ultraviolet light can vary depending on the spectrum exhibited by the dielectric compound, the spectrum exhibited by the first compound, the amount of the first compound dissolved in the working fluid, and the operator's choice. More specifically, the ultraviolet absorption spectrum of the working fluid or the first dielectric compound and the ultraviolet absorption spectrum of the first compound are obtained or referenced from a spectral library. Any wavelength at which the first compound's spectrum shows a peak and the first dielectric compound is transparent can be selected as λ1. In some aspects, λ1 is in the range of 210 nm to 305 nm. In some aspects, λ1 is in the range of 900 nm to 2500 nm. In some aspects, λ1 is expressed in wavenumber at 500 cm⁻¹. -1 Up to 4000cm -1 Within a certain range. In some aspects, λ1 is in the range of 260nm to 290nm. In other aspects, λ1 is 240nm, 283nm, or 290nm.

[0076] In some aspects, the absorbance-based spectrophotometric technique of the present invention can utilize ultraviolet light at more than one predetermined wavelength. For example, at a given wavelength, if the absorbance response is linear in a relatively low concentration range (e.g., 1-10 ppm) of the first compound, but not linear in a relatively high concentration range (e.g., 50-100 ppm) and exceeds the ability of a radiation detector or transducer to accurately detect it, then ultraviolet light at a first predetermined wavelength can be used to calculate the concentration of the first compound at a relatively low concentration, while ultraviolet light at a second predetermined wavelength can be used to calculate the concentration of the first compound at a relatively high concentration. In some aspects, the data acquisition and processing unit outputs a signal indicating the measured concentration.

[0077] Systems for immersion cooling

[0078] Systems for immersion cooling are adapted and configured to cool articles by direct heat exchange with a liquid working fluid in the immersion cooling apparatus. The system includes an absorbance-type spectrophotometer for monitoring contaminants. In some aspects, the immersion cooling apparatus is a single-phase immersion cooling apparatus, wherein the temperature of the working fluid is maintained below the boiling point of the dielectric compound. In other aspects, the immersion cooling apparatus is a two-phase immersion cooling apparatus, wherein the heat removed from the article to be cooled causes the working fluid to boil at one or more surfaces of the article to be cooled.

[0079] In some aspects, such as Figure 1 As shown, the immersion cooling device includes a housing 101, the inner surface of which defines a sealable internal cavity that houses an article 103 to be cooled, which is at least partially immersed in a working fluid in liquid form comprising a first dielectric compound. The article 103 includes the first compound and may have one or more heat sinks 105 for efficiently transferring heat from the relatively hot article 103 to the relatively cool working fluid.

[0080] An absorbance-based spectrophotometric device (not shown) for measuring the absorbance of a portion of the working fluid (i.e., a sample of the working fluid) can be obtained by any means known to those skilled in the art.

[0081] Optionally, the immersion cooling apparatus further includes an adsorption filter (not shown) to which a flow of working fluid, generated by a pump (not shown), is supplied. The adsorption filter includes an adsorbent material adapted and configured to adsorb contaminants, including a first compound, within the working fluid. In some aspects, the adsorbent material is configured to adsorb one or more of di(2-ethylhexyl) phthalate, di(2-ethylhexyl) terephthalate, diisodecyl phthalate, and tri(2-ethylhexyl) trimellitate. In some aspects, the adsorbent material is selected from activated carbon, alumina, and molecular sieves. Optionally, the adsorption filter is configured to be in fluid communication therebetween.

[0082] In some aspects, such as Figure 2 As shown, the immersion cooling device (for the immersion cooling system) is a single-phase cooling device including a housing 201. The inner surface of the housing 201 defines a sealable internal cavity 202 that contains an article 203 to be cooled, which is completely immersed in a working fluid in liquid form. The article 203 may have one or more radiators 205 for efficiently transferring heat from the relatively hot article 203 to the relatively cool working fluid.

[0083] The temperature of the working fluid is maintained below the boiling point of the dielectric compound via a recirculation system 207 and a heat transfer device 209, the heat transfer device 209 being adapted and configured to actively or passively remove heat from the dielectric compound flowing through the recirculation system 207. Non-limiting examples of the heat transfer device 209 include a radiator, heat exchanger, or cooler. The recirculation system 207 includes an inlet 211 in fluid communication with the interior downstream of the cavity 202, an outlet 213 in fluid communication with the interior upstream of the cavity 202, and a pump (not shown) for causing the working fluid to flow from the cavity 202 into the inlet 211 and return to the cavity 202 via the outlet 213. The heat transfer device 209 is configured to be in fluid communication between the inlet 211 and the outlet 213 and is adapted and configured to cool the flow of the working fluid pumped by the pump. In this way, the temperature of the article 203 to be cooled is controlled by controlling the degree of cooling of the working fluid by the heat transfer device 209.

[0084] An absorbance-based spectrophotometric device (not shown) for measuring the absorbance of a portion of the working fluid (i.e., a sample of the working fluid) can be obtained by any means known to those skilled in the art.

[0085] Optionally, the immersion cooling device may include an adsorption filter (not shown) to which a flow of working fluid, generated by a pump (not shown), is supplied. The adsorption filter includes an adsorbent material adapted and configured to adsorb contaminants, including a first compound, within the working fluid. In some aspects, the adsorbent material is configured to adsorb one or more of di(2-ethylhexyl) phthalate, di(2-ethylhexyl) terephthalate, diisodecyl phthalate, and tri(2-ethylhexyl) trimellitate. In some aspects, the adsorbent material is selected from activated carbon, alumina, and molecular sieves. Optionally, the adsorption filter is arranged in series with the recirculation system 207 and the heat transfer device 209.

[0086] In some aspects, such as Figure 3 As shown, the immersion cooling system is a single-phase cooling system including an immersion cooling device. The immersion cooling device includes a housing 301, the inner surface of which defines a sealable internal cavity 302. The internal cavity 302 contains an item 303 to be cooled, which is completely immersed in a working fluid in liquid form. The item 303 may have one or more radiators 305 for effectively transferring heat from the relatively hot item 303 to the relatively cool working fluid.

[0087] The temperature of the working fluid is maintained below the boiling point of the dielectric compound via a recirculation system 307 and a heat transfer device 309. The recirculation system 307 includes an inlet 311 in fluid communication downstream of the interior of the cavity 302, an outlet 313 in fluid communication upstream of the interior of the cavity 302, and a pump (not shown) for inducing the working fluid to flow from the cavity 302 into the inlet 311 and return to the cavity 302 via the outlet 313. The heat transfer device 309 is configured to be in fluid communication between the inlet 311 and the outlet 313 and is adapted and configured to cool the flow of the working fluid pumped by the pump. In this way, the temperature of the article 303 to be cooled is controlled by controlling the degree of cooling of the working fluid by the heat transfer device 309.

[0088] Optionally, the immersion cooling apparatus further includes an adsorption filter (not shown) to which a flow of working fluid, generated by a pump (not shown), is supplied. The adsorption filter includes an adsorbent material adapted and configured to adsorb contaminants, including a first compound, within the working fluid. In some aspects, the adsorbent material is configured to adsorb one or more of di(2-ethylhexyl) phthalate, di(2-ethylhexyl) terephthalate, diisodecyl phthalate, and tri(2-ethylhexyl) trimellitate. In some aspects, the adsorbent material is selected from activated carbon, alumina, and molecular sieves. Optionally, the adsorption filter is arranged in series with a recirculation system 307 and a heat transfer device 309.

[0089] exist Figure 3 In the system, the absorbance-type spectrophotometer includes an in-situ probe 315 and a data acquisition and processing unit 317. The probe 315 measures the absorbance of a portion of the working fluid (i.e., a sample of the working fluid) at its tip 319 and transmits a signal representing the absorbance measured as described above to the data acquisition and processing unit 315.

[0090] In some aspects, such as Figure 4 As shown, the immersion cooling device (of the immersion cooling system) is a single-phase cooling device including a housing 401. The inner surface of the housing 401 defines a sealable internal cavity 402 that contains an item 403 to be cooled, which is completely immersed in a working fluid in liquid form. The item 403 may have one or more radiators 405 for efficiently transferring heat from the relatively hot item 403 to the relatively cool working fluid.

[0091] The temperature of the working fluid is maintained below the boiling point of the dielectric compound via a recirculation system 407 and a heat transfer device 409. The recirculation system 407 includes an inlet 411 in fluid communication downstream of the interior of the cavity 402, an outlet 413 in fluid communication upstream of the interior of the cavity 402, and a pump (not shown) for causing the working fluid to flow from the cavity 402 into the inlet 411 and return to the cavity 402 via the outlet 413. The heat transfer device 409 is configured to be in fluid communication between the inlet 411 and the outlet 413 and is adapted and configured to cool the flow of the working fluid pumped by the pump. In this way, the temperature of the article 403 to be cooled is controlled by controlling the degree of cooling of the working fluid by the heat transfer device 409.

[0092] Optionally, the immersion cooling device further includes an adsorption filter (not shown) to which a flow of working fluid, generated by a pump (not shown), is supplied. The adsorption filter includes an adsorbent material adapted and configured to adsorb contaminants, including a first compound, within the working fluid. In some aspects, the adsorbent material is configured to adsorb one or more of di(2-ethylhexyl) phthalate, di(2-ethylhexyl) terephthalate, diisodecyl phthalate, and tri(2-ethylhexyl) trimellitate. Optionally, the adsorbent material is selected from activated carbon, alumina, and molecular sieves. In some aspects, the adsorption filter is arranged in series with a recirculation system 407 and a heat transfer device 409.

[0093] The absorbance-type spectrophotometer includes a draw tube 421 and a spectrophotometer 423. The working fluid is drawn from the cavity 402 through the draw tube 421 and guided to the spectrophotometer 423 (as described above) via a pump (not shown), where its absorbance is measured.

[0094] In some aspects, such as Figure 5 As shown, the immersion cooling device (of the immersion cooling system) is a two-phase cooling device comprising a housing 501, the inner surface of which defines a sealable internal cavity containing an article 503 to be cooled, which is partially immersed in the liquid phase 504 of the working fluid. The article 503 may have one or more radiators for efficiently transferring heat from the relatively hot article 503 to the relatively cool working fluid. A spectrophotometric device (not shown) for measuring the absorbance of a portion of the working fluid (i.e., a sample of the working fluid) may be obtained in any manner known to those skilled in the art.

[0095] The latent heat of vaporization of the dielectric compound is used to remove heat from the article 503 to be cooled. Therefore, the boiling temperature of the first dielectric compound will largely determine the operating temperature of the article 503 to be cooled. In some respects, this control of the operating temperature of the article 503 to be cooled can be modified to lower or raise the operating temperature by reducing or raising the pressure within the top space 506 above the liquid phase 504, thereby correspondingly lowering or raising the boiling point of the working fluid. Those skilled in the art will recognize that, Figure 5 In a two-phase immersion cooling apparatus, the working fluid boils at one or more surfaces (such as a radiator 505) of the article 503 to be cooled. The boiling of the first dielectric compound produces vapor, which rises as bubbles 508 through the liquid phase 504 and into the top space 506 above the liquid phase 504.

[0096] Vapor condenses at a condenser 523 located within the top space 506 and falls back into the liquid phase 504 as droplets 525. The recirculation system 527 includes an inlet 529 in fluid communication with the interior of the condenser 523, an outlet 531 in fluid communication with the interior of the condenser 523, a heat transfer device 533 in fluid communication between the inlet 529 and the outlet 531, and a pump (not shown). The pump causes coolant to flow from the interior of the condenser 523 through the inlet 529 to the interior of the heat transfer device 533, where the coolant is cooled to a temperature below the vapor dew point. The cooled coolant then flows out of the heat transfer device 533 and returns to the interior of the condenser 523 through the outlet 531. In some aspects, the coolant is water or a mixture of water and glycol (e.g., ethylene glycol or propylene glycol).

[0097] The spectrophotometric apparatus (not shown) used to measure the absorbance of a portion of the working fluid (i.e., a sample of the working fluid) can be obtained by any means known to those skilled in the art.

[0098] The immersion cooling device also includes an adsorption filter 535, to which a flow of working fluid, generated by a pump (not shown), is supplied. The adsorption filter 535 includes an adsorbent material adapted and configured to adsorb contaminants, including a first compound, within the working fluid. In some aspects, the adsorption filter material is selected from activated carbon, alumina, and molecular sieves.

[0099] In some aspects, such as Figure 6 As shown, the immersion cooling device (of the immersion cooling system) is a two-phase cooling device comprising a housing 601. The inner surface of the housing 601 defines a sealable internal cavity that contains an article 603 to be cooled, which is partially immersed in the liquid phase 604 of the working fluid. The article 603 may have one or more radiators for efficiently transferring heat from the relatively hot article 603 to the relatively cool working fluid.

[0100] The latent heat of vaporization of the dielectric compound is used to remove heat from the article 603 to be cooled. Therefore, the boiling temperature of the first dielectric compound will largely determine the operating temperature of the article 603 to be cooled. In some respects, this control of the operating temperature of the article 603 to be cooled can be modified to lower or raise the operating temperature by decreasing or increasing the pressure within the top space 606 above the liquid phase 604, thereby correspondingly decreasing or increasing the boiling point of the working fluid. Those skilled in the art will recognize that, Figure 6 In a two-phase immersion cooling apparatus, the working fluid boils at one or more surfaces (such as a radiator 605) of the article 603 to be cooled. The boiling of the first dielectric compound produces vapor, which rises as bubbles 608 through the liquid phase 604 and into the top space 506 above the liquid phase 604.

[0101] Vapor condenses at a condenser 623 located within the top space 606 and falls back into the liquid phase 604 as droplets 625. The recirculation system 627 includes an inlet 629 in fluid communication with the interior of the condenser 623, an outlet 631 in fluid communication with the interior of the condenser 623, a heat transfer device 633 in fluid communication between the inlet 629 and the outlet 631, and a pump (not shown). The pump causes coolant to flow from the interior of the condenser 623 through the inlet 629 to the interior of the heat transfer device 633, where the coolant is cooled to a temperature below the vapor dew point. The cooled coolant then flows out of the heat transfer device 633 and returns to the interior of the condenser 623 through the outlet 631. In some aspects, the coolant is a mixture of water and glycol (e.g., ethylene glycol or propylene glycol).

[0102] exist Figure 6In the system, the absorbance-type spectrophotometer includes an in-situ probe 615 and a data acquisition and processing unit 617. The probe 615 measures the absorbance of a portion of the working fluid (i.e., a sample of the working fluid) at its tip 619 and transmits a signal representing the absorbance measured as described above to the data acquisition and processing unit 615.

[0103] The immersion cooling device also includes an adsorption filter 635, to which a flow of working fluid, generated by a pump (not shown), is supplied. The adsorption filter 635 includes an adsorbent material adapted and configured to adsorb contaminants, including a first compound, within the working fluid. In some aspects, the adsorption filter material is selected from activated carbon, alumina, and molecular sieves.

[0104] In some aspects, such as Figure 7 As shown, the immersion cooling device (of the immersion cooling system) is a two-phase cooling device comprising a housing 701. The inner surface of the housing 701 defines a sealable internal cavity that contains an article 703 to be cooled, which is partially immersed in the liquid phase 704 of the working fluid. The article 703 may have one or more radiators for efficiently transferring heat from the relatively hot article 703 to the relatively cool working fluid.

[0105] The latent heat of vaporization of the dielectric compound is used to remove heat from the article 703 to be cooled. Therefore, the boiling temperature of the first dielectric compound will largely determine the operating temperature of the article 703 to be cooled. In some respects, this control of the operating temperature of the article 703 to be cooled can be modified to lower or raise the operating temperature by reducing or raising the pressure within the top space 706 above the liquid phase 704, thereby correspondingly lowering or raising the boiling point of the working fluid. Those skilled in the art will recognize that, Figure 7 In a two-phase immersion cooling apparatus, the working fluid boils at one or more surfaces (such as a radiator 705) of the article 703 to be cooled. The boiling of the first dielectric compound produces vapor, which rises as bubbles 708 through the liquid phase 704 and into the top space 506 above the liquid phase 704.

[0106] Vapor condenses at a condenser 723 located within the top space 706 and falls back into the liquid phase 504 as droplets 725. The recirculation system 727 includes an inlet 729 in fluid communication with the interior of the condenser 723, an outlet 731 in fluid communication with the interior of the condenser 723, a heat transfer device 733 in fluid communication between the inlet 729 and the outlet 731, and a pump (not shown). The pump causes coolant to flow from the interior of the condenser 723 through the inlet 729 to the interior of the heat transfer device 733, where the coolant is cooled to a temperature below the vapor dew point. The cooled coolant then flows out of the heat transfer device 733 and returns to the interior of the condenser 723 through the outlet 731. In some aspects, the coolant is water or a mixture of water and glycol (e.g., ethylene glycol or propylene glycol).

[0107] The absorbance-type spectrophotometer includes a draw tube 721 and a spectrophotometer 723. A pump (not shown) is used to draw the working fluid from the cavity 702 through the draw tube 721 and guide it to the spectrophotometer 723 (as described above), where its absorbance is measured.

[0108] The immersion cooling device also includes an adsorption filter 735, to which a flow of working fluid, generated by a pump (not shown), is supplied. The adsorption filter 735 includes an adsorbent material adapted and configured to adsorb contaminants, including a first compound, within the working fluid. In some aspects, the adsorption filter material is selected from activated carbon, alumina, and molecular sieves.

[0109] Methods for monitoring contaminants dissolved in working fluids

[0110] The working fluid removes heat from the item to be cooled in the immersion cooling device. Over time, a certain amount of the first compound in the item to be cooled dissolves in the working fluid.

[0111] An absorbance-based spectrophotometer is used to measure the absorbance of a portion of the working fluid to ultraviolet light at a first predetermined wavelength. In some aspects, the absorbance-based spectrophotometer is used to measure the absorbance of a portion of the working fluid to ultraviolet light at a first plurality of predetermined wavelengths. Using the absorbance-based spectrophotometer, an initial concentration representing the concentration of a first compound dissolved in the working fluid is calculated, wherein this calculation is based on the measured absorbance and also on standard absorbance values ​​stored in the memory of the absorbance-based spectrophotometer. The standard absorbance values ​​correspond to the absorbance of one or more standard solutions of the first compound, comprising known concentrations in the working fluid, to ultraviolet light at the first predetermined wavelength.

[0112] In some respects, additional monitoring may be performed after the aforementioned measurement and calculation steps and after an additional period of time. The absorbance of another portion of the working fluid to ultraviolet light at a second predetermined wavelength is measured using an absorbance-based spectrophotometer. Using the absorbance-based spectrophotometer, a subsequent concentration representing the concentration of the first compound dissolved in the working fluid is calculated. This calculation is based on the measured absorbance and a standard absorbance value.

[0113] In some aspects, filters comprising adsorbent materials adapted and configured to adsorb the first compound can be used to remove a certain amount of the dissolved first compound from the working fluid. Further monitoring can be performed after the foregoing measurement and calculation steps and after an additional period of time. The absorbance of another portion of the working fluid to ultraviolet light at a second predetermined wavelength is measured using an absorbance-based spectrophotometer. Using the absorbance-based spectrophotometer, a subsequent concentration representing the concentration of the first compound dissolved in the working fluid is calculated. This calculation is based on the measured absorbance and a standard absorbance value. In response to a subsequent concentration higher than a predetermined concentration value, at least one of the following actions is performed: 1) replacing the adsorbent material; 2) replacing at least a portion of the working fluid with a certain amount of the dielectric compound that does not have a detectable amount of the first compound; and 3) purifying the working fluid to remove a certain amount of the first compound.

[0114] In some aspects, the working fluid includes a first dielectric compound selected from the following: E-1,1,1,2,2,5,5,6,6,6-decafluoro-3-hexene (HFO-153-10mczz-E); E-1,1,1,4,5,5,5-heptafluoro-4-trifluoromethyl-2-pentene (HFO-153-10mzzy-E); and Z-1,1,1,4,4,4-hexafluoro-2-butene (HFO-1336mzz), and the first compound is selected from: di(2-ethylhexyl) phthalate, di(2-ethylhexyl) terephthalate, diisodecyl phthalate, and tri(2-ethylhexyl) trimellitate.

[0115] Example

[0116] Example 1: Three different DOTP solutions were prepared in HFO-153-10mczz-E: 25 ppm (w / w), 50 ppm (w / w), and 100 ppm (w / w). The spectra of each were obtained using an Agilent Cary 60 UV-vis spectrophotometer equipped with a quartz cuvette with a 1 cm path length. The absorbance of these three solutions at specified wavelengths was plotted as a function of concentration. The concentration of an unknown substance can be determined according to Beer-Lambert's law. The absorbance of the same plasticizer contaminant at different wavelengths can be used to determine its concentration. Calibration curves were plotted at 293 nm and 282 nm for DOTP in HFO-153-10mczz-E using the obtained absorbance, as shown below. Figure 8 As shown.

[0117] Example 2: Three different DOTP solutions were prepared in HFO-153-10mczz-E: 25 ppm (w / w), 50 ppm (w / w), and 100 ppm (w / w). Spectra for each were obtained using an Agilent Cary 60 UV-vis spectrophotometer equipped with a quartz cuvette with a 1 cm path length. The concentration of the plasticizer contaminant was determined using calibration curves. According to Beer-Lambert's law, the absorbance of the same plasticizer contaminant at different wavelengths can be used to determine its concentration. Calibration curves were plotted at 273 nm using the obtained absorbances against DOTP dissolved in HFO-153-10-mczz-E, as shown below. Figure 9 As shown.

[0118] Example 3: Three different TOTM solutions were prepared in HFO-153-10mczz-E: 25 ppm (w / w), 50 ppm (w / w), and 100 ppm (w / w). Spectra were obtained using an Agilent Cary 60 UV-vis spectrophotometer equipped with a quartz cuvette with a 1 cm path length. The concentration of the plasticizer contaminant was determined using a calibration curve. According to Beer-Lambert's law, the absorbance of the same plasticizer contaminant at different wavelengths can be used to determine its concentration. A calibration curve was plotted at 281 nm for TOTM dissolved in HFO-153-10-mczz-E using the obtained absorbance, as shown below. Figure 10 As shown.

[0119] Example 4: Different DOTP solutions were prepared in HFO-153-10mczz-E: 25 ppm (w / w), 50 ppm (w / w), and 100 ppm (w / w). Spectra were obtained using an Agilent Cary 60 UV-vis spectrophotometer equipped with a quartz cuvette with a 1 cm path length. These spectra show that plasticizers can be quantified using a range of wavelengths, particularly those between 250-300 nm. The obtained spectra are as follows... Figure 11 As shown.

[0120] Example 5: UV-Vis spectra of pure HFO-153-10-mczz-E and a working fluid (used in an immersion tank) made from plasticizer-contaminated HFO-153-10-mczz-E were obtained using an Agilent Cary 60 UV-Vis spectrophotometer equipped with a quartz cuvette with a 1 cm path length. The differences between the clean and contaminated spectra were significant, such as… Figure 12 As shown.

[0121] Example 6: Using an Agilent Cary 60 UV-vis spectrophotometer equipped with a quartz cuvette with a 1 cm path length, UV-Vis spectra of HFO-135-10mczz-E with and without 100 ppm (w / w) DOTP, and Novec 649 with and without 100 ppm (m / m) DOTP were obtained. Figure 13 As shown, the absorption spectrum of Novec 649 absorbs light at wavelengths much higher than any plasticizer or HFO fluid. Due to this absorbance, UV-Vis spectroscopy cannot be used to detect plasticizers in Novec 649.

[0122] Example 7: Obtaining UV-Vis spectra of three different HFOs (HFO-153-10mzzy-E, HFO-153-10mczz-E, and HFO-1336mzz-Z) and the same HFO with 100 ppm DOTP (w / w). Solutions were prepared in each HFO with 100 ppm (w / w) DOTP, and spectra were obtained using an Agilent Cary 60 UV-vis spectrophotometer equipped with quartz cuvettes with a 1 cm path length. Figure 14 As shown, HFO is optically transparent in the region of interest where the plasticizer absorbs light, and the presence of the plasticizer can be easily detected.

[0123] The technology of this invention exhibits several advantages.

[0124] First, because the technique of the present invention utilizes a first dielectric compound that is transparent at λ1, it does not prevent the calculation of the concentration of the first compound using absorbance-type spectrophotometry. Conversely, each of the known immersion-cooled dielectric fluids Novec 649, PF5060, and Novec 7200 exhibits one or more absorption peaks in the ultraviolet spectrum, thus interfering with the quantification of the first compound.

[0125] Secondly, before the filter penetrates and / or contaminants in solid form are excessively deposited on the surfaces within the immersion cooling unit, any adsorption filter media present in the immersion cooling unit used to adsorb and filter out contaminants may be replaced.

[0126] Third, before the filter penetrates and / or contaminants in solid form are excessively deposited on the surfaces within the immersion cooling unit, some or all of the working fluid (when it is excessively contaminated) can be replaced with an industrially pure first dielectric compound.

[0127] Fourth, additional adsorption filter capacity can be added before filter penetration and / or excessive deposition of contaminants in solid form on the surfaces within the immersion cooling unit (when the working fluid is excessively contaminated).

[0128] Fifth, before the filter penetrates and / or contaminants in solid form are excessively deposited on the surfaces within the immersion cooling unit, replenishment or alternative purification of the working fluid may be performed (when the working fluid is excessively contaminated).

[0129] Sixth, compared to conventional contamination monitoring techniques that rely on detecting solid deposits of contaminants already formed on the surface of an immersion cooling device, the technology of the present invention has the ability to detect excessive contamination levels at points in time when such conventional techniques cannot detect them. At excessive contamination levels not exceeding the solubility limit of the first compound in the working fluid, the technology of the present invention has the ability to detect and calculate the concentration of the first compound. On the other hand, such conventional techniques cannot detect the presence of the first compound until it exceeds the solubility limit of the working fluid and forms deposits, solid deposits, or corrosion in the form of oily residues. They can also be advantageously compared to conventional contamination monitoring techniques that are unsatisfactorily inaccurate or insensitive to relatively low levels of contaminants (e.g., below 200 ppm, below 175 ppm, below 150 ppm, below 125 ppm, below 100 ppm, below 75 ppm, below 50 ppm, below 25 ppm, or below 10 ppm).

Claims

1. A method for monitoring contaminants dissolved in the working fluid of an immersion cooling device, comprising the following steps: An immersion cooling device is provided, comprising a housing, the inner surface of which defines a sealable internal cavity containing an article to be cooled that is at least partially immersed in a liquid phase of a working fluid, wherein the working fluid comprises a first dielectric compound, the article to be cooled comprises a first compound soluble in the first dielectric compound, and the working fluid comprises an amount of the first compound dissolved therein. The absorbance of a portion of the working fluid to ultraviolet light at a predetermined wavelength λ1 is measured using an absorbance-based spectrophotometer, wherein the first dielectric compound is transparent to ultraviolet light at λ1 and the first compound is opaque to ultraviolet light at λ1. Using the absorbance-based spectrophotometer, a first concentration representing the concentration of the first compound dissolved in the working fluid is calculated based on the measured absorbance and a standard absorbance value stored in the memory of the absorbance-based spectrophotometer, the standard absorbance value corresponding to the absorbance at λ1 of a standard solution of the first compound comprising a known concentration in the working fluid.

2. The method according to claim 1, wherein: The immersion cooling device is a single-phase cooling device; The item to be cooled is completely immersed in the working fluid and maintained at an operating temperature below the boiling temperature of the first dielectric compound; The immersion cooling device further includes an inlet and an outlet, the inlet being adapted and configured to receive the working fluid cooled at a heat transfer device and entering the cavity, the outlet being adapted and configured to guide the working fluid from the cavity to the heat transfer device, the heat transfer device being adapted and configured to actively or passively remove heat from the working fluid; and The method further includes the steps of: pumping the working fluid from the outlet to the inlet through the heat transfer device; and removing heat from the heat transfer device to cool the working fluid therein.

3. The method according to claim 1, wherein: The immersion cooling device is a two-phase cooling device; The operating temperature of the item to be cooled is higher than the boiling point of the first dielectric compound, and the first dielectric compound boils at one or more portions of the item to be cooled, thereby generating vapor in the top space above the liquid phase of the working fluid. The vapor condenses at a condenser located within the top space; and The method further includes the steps of: pumping a heat transfer fluid through the condenser, and cooling the heat transfer fluid to a temperature below the boiling point of the first dielectric compound using a heat transfer device adapted to actively or passively remove heat from the heat transfer fluid.

4. The method of claim 1, wherein the immersion cooling device further comprises an adsorption filter having an inlet and an outlet in fluid communication with the working fluid and comprising an adsorption medium adapted and configured to adsorb the first compound.

5. The method according to claim 4, further comprising the following step: When the calculated concentration is higher than the predetermined concentration, the adsorption medium is replaced.

6. The method according to claim 5, wherein the predetermined concentration is selected from: 200ppm, 100ppm, 50ppm, 25ppm, 10ppm and 5ppm.

7. The method according to claim 4, further comprising the following step: When the calculated concentration is higher than the predetermined concentration, at least a portion of the working fluid is replaced.

8. The method according to claim 7, wherein the predetermined concentration is selected from 100 ppm, 50 ppm, 25 ppm, 10 ppm and 5 ppm.

9. The method of claim 1, wherein the article to be cooled further comprises a second compound soluble in the first dielectric compound, and the working fluid comprises an amount of the second compound dissolved therein, and wherein the method further comprises the following steps: The absorbance of a portion of the working fluid to ultraviolet light at a predetermined wavelength λ2 is measured using an absorbance-based spectrophotometer, wherein the first dielectric compound is transparent to ultraviolet light at λ2, and the second compound is opaque to ultraviolet light at λ2. Using the absorbance-based spectrophotometer, a second concentration representing the concentration of the second compound dissolved in the working fluid is calculated based on the measured absorbance and the standard absorbance value.

10. The method of claim 9, wherein the immersion cooling apparatus further comprises an adsorption filter having an inlet and an outlet in fluid communication with the working fluid and comprising an adsorption medium adapted and configured to adsorb the first compound.

11. The method of claim 10, further comprising the step of: When the first calculated concentration or the second calculated concentration is higher than the predetermined concentration, the adsorption medium is replaced.

12. The method of claim 11, wherein the predetermined concentration is selected from: 200 ppm, 150 ppm, 100 ppm, 50 ppm, 25 ppm, 10 ppm and 5 ppm.

13. The method of claim 10, further comprising the step of: When the first calculated concentration or the second calculated concentration is higher than the predetermined concentration, at least a portion of the working fluid is replaced.

14. The method of claim 13, wherein the predetermined concentration is selected from: 200 ppm, 150 ppm, 100 ppm, 50 ppm, 25 ppm, 10 ppm and 5 ppm.

15. The method of claim 10, further comprising the step of: When the first calculated concentration or the second calculated concentration is higher than the predetermined concentration, at least a portion of the working fluid is purified to remove a certain amount of the first compound.

16. The method of claim 15, wherein the predetermined concentration is selected from: 200 ppm, 150 ppm, 100 ppm, 50 ppm, 25 ppm, 10 ppm and 5 ppm.

17. The method according to claim 1, wherein the first dielectric compound is selected from: E-1,1,1,2,2,5,5,6,6,6-decafluoro-3-hexene (HFO-153-10mczz-E), Z-1,1,1,2,2,5,5,6,6,6-decafluoro-3-hexene (HFO-153-10mczz-Z), E-1,1,1,4,5,5,5-heptafluoro-4-trifluoromethyl-2-pentene (HFO-153-10mzzy-E), Z-1, 1,1,4,5,5,5-Hepanofluoro-4-trifluoromethyl-2-pentene (HFO-153-10mzzy-Z), E-1,1,1,4,4,4-hexafluoro-2-butene (HFO-1336mzz-E), Z-1,1,1,4,4,4-hexafluoro-2-butene (HFO-1336mzz-Z), hexafluoropropylene dimer, E-perfluoro(4-methyl-2-pentene), perfluoro-2-methyl-2-pentene, Z-perfluoro(4-methyl-2-pentene), and hexafluoropropylene trimer.

18. The method of claim 17, wherein the working fluid further comprises a second dielectric compound different from the first dielectric compound, the first dielectric compound being present in the working fluid at a concentration of at least 99% by weight.

19. The method according to claim 17, wherein the second dielectric compound is selected from: E-1,1,1,2,2,5,5,6,6,6-decafluoro-3-hexene (HFO-153-10mczz-E); Z-1,1,1,2,2,5,5,6,6,6-decafluoro-3-hexene (HFO-153-10mczz-Z); E-1,1,1,4,5,5,5-heptafluoro-4-trifluoromethyl-2-pentene (HFO-153-10mzzy-E); Z-1,1,1,4,5,5,5-heptafluoro-4-trifluoromethyl-2-pentene (HFO-153-10mzzy-Z) E-1,1,1,4,4,4-hexafluoro-2-butene (HFO-1336mzz-E), Z-1,1,1,4,4,4-hexafluoro-2-butene (HFO-1336mzz-Z); 1,1,1,2,2,3,3,4,4,5,5,6,6,6-tetradecoxane; hexafluoropropylene dimer; E-perfluoro(4-methyl-2-pentene); perfluoro-2-methyl-2-pentene, Z-perfluoro(4-methyl-2-pentene); hexafluoropropylene trimer; ethyl nonafluoroisobutyl ether; ethyl nonafluorobutyl ether; and 1,1,1,2,2,4,5,5,5-nonafluoro-4-(trifluoromethyl)-3-pentanone.

20. The method according to claim 1, wherein the first compound is a phthalate or a terephthalate.

21. The method according to claim 1, wherein the first compound is selected from: di(2-ethylhexyl) phthalate, di(2-ethylhexyl) terephthalate, diisodecyl phthalate, and tri(2-ethylhexyl) trimellitate.

22. The method of claim 1, wherein the first predetermined wavelength is in the range of 210 nm to 305 nm.

23. The method of claim 1, wherein the first predetermined wavelength is in the range of 240 nm to 295 nm.

24. The method of claim 1, wherein the first predetermined wavelength is in the range of 900 nm to 2500 nm.

25. The method of claim 1, wherein the first predetermined wavelength is expressed in wavenumber at 500 cm⁻¹ -1 Up to 4000cm -1 Within the range.

26. The method of claim 1, wherein the article to be cooled is an electronic component selected from: high-capacity energy storage devices, computer servers, data center servers, GPUs, CPUs, solar photovoltaics, batteries, insulated-gate bipolar transistor (IGBT) devices, telecommunications infrastructure, military electronic devices, televisions, mobile phones, monitors, drones, automotive batteries, power systems for electric vehicles, power electronic devices, avionics equipment, power equipment, power transformers, and displays.

27. A method for monitoring contaminants dissolved in the working fluid of an immersion cooling device, comprising the following steps: (a) Provides an immersion cooling device including a housing, the inner surface of the housing defining a sealable internal cavity containing an article to be cooled that is at least partially immersed in a liquid phase of a working fluid, wherein the working fluid includes a first dielectric compound, the article to be cooled includes a first compound soluble in the first dielectric compound, and the working fluid includes an amount of the first compound dissolved therein. (b) Using an absorbance-based spectrophotometer, the absorbance of a portion of the working fluid to ultraviolet light at a first predetermined wavelength is measured, wherein the first dielectric compound is transparent to ultraviolet light at the first predetermined wavelength and the first compound is opaque to ultraviolet light at the first predetermined wavelength. (c) Using the absorbance-based spectrophotometer, a first concentration representing the concentration of the first compound dissolved in the working fluid is calculated based on the measured absorbance at the first predetermined wavelength and a standard absorbance value stored in the memory of the absorbance-based spectrophotometer, the standard absorbance value corresponding to the absorbance of a standard solution of the first compound comprising a known concentration in the working fluid to ultraviolet light at the first predetermined wavelength. (d) After step (c), a period of time is allowed during which a certain amount of the first compound is dissolved in the working fluid, such that the concentration of the first compound in the working fluid increases compared to the concentration of the first compound in the working fluid before step (c); (e) Using the absorbance-based spectrophotometer, measure the absorbance of a portion of the working fluid to ultraviolet light at a second predetermined wavelength, wherein the first dielectric compound is transparent to ultraviolet light at the second predetermined wavelength and the first compound is opaque to ultraviolet light at the second predetermined wavelength; as well as (f) After step (d), using the absorbance-based spectrophotometer, a second concentration representing the concentration of the first compound dissolved in the working fluid is calculated based on the measured absorbance at the second predetermined wavelength and the standard absorbance value.

28. A method for monitoring contaminants dissolved in the working fluid of an immersion cooling device, comprising: (a) Cooling an article to be cooled by direct heat exchange with a liquid working fluid in an immersion cooling device, the article to be cooled comprising a first compound soluble in the first dielectric compound, the working fluid comprising a certain amount of the first compound dissolved therein; (b) Removing a certain amount of the dissolved first compound from the working fluid using an adsorption filter, the adsorption filter comprising an adsorbent material adapted and configured to adsorb the first compound; (c) Using an absorbance-based spectrophotometer, the absorbance of a portion of the working fluid to ultraviolet light at a predetermined wavelength λ is measured to generate an initial absorbance value, wherein the first dielectric compound is transparent to ultraviolet light at the first predetermined wavelength and the first compound is opaque to ultraviolet light at the first predetermined wavelength. (d) Using the absorbance-based spectrophotometer, based on the initial absorbance value and a standard absorbance value stored in the memory of the absorbance-based spectrophotometer, calculate an initial concentration value representing the concentration of the first compound dissolved in the working fluid, the standard absorbance value corresponding to the absorbance of a standard solution of the first compound comprising a known concentration in the working fluid to ultraviolet light at the first predetermined wavelength. (e) After step (d), a period of time is allowed during which a certain amount of the first compound is dissolved in the working fluid, such that the concentration of the first compound in the working fluid increases compared to the concentration of the first compound in the working fluid before step (d). (f) Repeat step (c) to generate subsequent absorbance values; (g) Using the absorbance-based spectrophotometer, a subsequent concentration value representing the concentration of the first compound dissolved in the working fluid is calculated based on the subsequent absorbance value and the stored standard absorbance value, the subsequent concentration being higher than a predetermined concentration value; as well as (h) In response to a calculation that the subsequent concentration value is higher than the predetermined concentration value: 1) replace the adsorbent material, 2) replace at least a portion of the working fluid with a certain amount of the dielectric compound that does not have a detectable amount of the first compound, or 3) purify at least a portion of the working fluid to remove a certain amount of the first compound therefrom.

29. The method of claim 28, wherein the working fluid comprises a first dielectric compound selected from the group consisting of: E-1,1,1,2,2,5,5,6,6,6-decafluoro-3-hexene (HFO-153-10mczz-E); E-1,1,1,4,5,5,5-heptafluoro-4-trifluoromethyl-2-pentene (HFO-153-10mzzy-E); and Z-1,1,1,4,4,4-hexafluoro-2-butene (HFO-1336mzz-Z).

30. The method according to claim 29, wherein the first compound is selected from: di(2-ethylhexyl) phthalate, di(2-ethylhexyl) terephthalate, diisodecyl phthalate, and tri(2-ethylhexyl) trimellitate.

31. A method for two-phase immersion cooling of an article to be cooled using a working fluid with monitored contamination levels, comprising: (a) Cooling an article to be cooled by direct heat exchange with a liquid working fluid in an immersion cooling device, the article to be cooled comprising a first compound soluble in the first dielectric compound, the working fluid comprising a certain amount of the first compound dissolved therein, the contact between the article to be cooled and the working fluid causing the working fluid to boil and generate vapor in the top space above the liquid working fluid; (b) The vapor is condensed using a condenser located in the overhead space; (c) Removing a certain amount of the dissolved first compound from the working fluid using an adsorption filter, the adsorption filter comprising an adsorbent material adapted and configured to adsorb the first compound; (d) Using an absorbance-based spectrophotometer, the absorbance of a portion of the working fluid to ultraviolet light at a predetermined wavelength λ in the range of 260 nm to 290 nm is measured to generate an initial absorbance value, wherein the first dielectric compound is transparent to ultraviolet light at the first predetermined wavelength and the first compound is opaque to ultraviolet light at the first predetermined wavelength. (e) Using the absorbance-based spectrophotometer, based on the initial absorbance value and a standard absorbance value stored in the memory of the absorbance-based spectrophotometer, calculate an initial concentration value representing the concentration of the first compound dissolved in the working fluid, the standard absorbance value corresponding to the absorbance of a standard solution of the first compound at a known concentration in the working fluid to ultraviolet light at the first predetermined wavelength. (f) After step (e), a period of time is allowed during which a certain amount of the first compound is dissolved in the working fluid, such that the concentration of the first compound in the working fluid increases compared to the concentration of the first compound present in the working fluid before step (e). (g) Repeat step (d) to generate subsequent absorbance values; (h) Using the absorbance-based spectrophotometer, a subsequent concentration value representing the concentration of the first compound dissolved in the working fluid is calculated based on the subsequent absorbance value and the stored standard absorbance value, the subsequent concentration being higher than a predetermined concentration value; as well as (i) In response to a calculation that the subsequent concentration value is higher than the predetermined concentration value: 1) replace the adsorbent material, 2) replace at least a portion of the working fluid with a certain amount of the dielectric compound that does not have a detectable amount of the first compound, or 3) purify the working fluid to remove a certain amount of the first compound.

32. The method according to claim 31, wherein: The working fluid comprises a first dielectric compound selected from the following: E-1,1,1,2,2,5,5,6,6,6-decafluoro-3-hexene (HFO-153-10mczz-E); E-1,1,1,4,5,5,5-heptafluoro-4-trifluoromethyl-2-pentene (HFO-153-10mzzy-E); and Z-1,1,1,4,4,4-hexafluoro-2-butene (HFO-1336mzz-Z); and The first compound is selected from: di(2-ethylhexyl) phthalate, di(2-ethylhexyl) terephthalate, diisodecyl phthalate and tri(2-ethylhexyl) trimellitate.

33. A system for immersion cooling of an article to be cooled, comprising: An immersion cooling device includes a housing and an adsorption filter, the inner surface of the housing defining a sealable internal cavity, and the adsorption filter including an adsorbent material adapted and configured to adsorb a first compound selected from: di(2-ethylhexyl) phthalate, di(2-ethylhexyl) terephthalate, diisodecyl phthalate, and tri(2-ethylhexyl) trimellitate; An article to be cooled is disposed within the cavity at a position suitable for and configured to be at least partially immersed in the liquid phase of the working fluid; as well as An absorbance-based spectrophotometer, wherein the absorbance-based spectrophotometer is adapted and configured to measure the absorbance of a portion of the working fluid to ultraviolet light at a first predetermined wavelength, and to calculate the concentration of the first compound in the working fluid based on the measured absorbance and a standard absorbance value of a standard solution containing a known concentration of the first compound in the working fluid to ultraviolet light at the first predetermined wavelength, the standard absorbance value being stored in the memory of the absorbance-based spectrophotometer, and the absorbance-based spectrophotometer displaying information indicating that the adsorbent material or at least a portion of the working fluid needs to be replaced.

34. The system of claim 33, wherein the immersion cooling device is a single-phase immersion cooling device, and the immersion cooling device further comprises a heat transfer device recirculation system adapted and configured to receive the working fluid at a first temperature from the cavity, introduce the working fluid into the heat transfer device, and return the working fluid to the cavity, wherein in the heat transfer device, the working fluid is cooled to a second temperature below the first temperature.

35. The system of claim 33, wherein the immersion cooling device is a two-phase immersion cooling device, and the immersion cooling device further comprises: A fluid condenser, wherein the fluid condenser is disposed within the cavity at a location suitably and configured to condense vapor generated by boiling of a working fluid at the surface of the article to be cooled; as well as A recirculation system comprising an inlet in fluid communication with the interior of the condenser, an outlet in fluid communication with the interior of the condenser, a pump in fluid communication between the inlet and the outlet, and a heat transfer device in fluid communication between the inlet and the outlet, the pump being adapted and configured to recirculate coolant from the interior of the condenser through the heat transfer device and back to the interior of the condenser, the heat transfer device being adapted and configured to cool the coolant thereon.

36. The system of claim 33, wherein the item to be cooled is selected from: high-capacity energy storage devices, computer servers, data center servers, solar photovoltaics, batteries, insulated-gate bipolar transistor (IGBT) devices, telecommunications infrastructure, military electronic devices, televisions, mobile phones, monitors, drones, automotive batteries, power systems for electric vehicles, power electronic devices, avionics equipment, power equipment, power transformers, and displays.

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