Methods for fluid contamination monitoring in real time with optics

Abstract

Section 1: Sensors and methods for monitoring immersion cooling fluid are disclosed. A sensor may include a measurement source and one or more detectors. The measurement source emits a measurement signal at a measurement media such as a transparent glass or plastic at least partially exposed to immersion cooling fluid. A sensor may include a heater to raise the temperature of immersion cooling fluid in contact with the measurement medium and promote nucleation of contaminants contained within the immersion cooling fluid onto the measurement medium. The detector receives a measurement signal, which is then used to determine a contamination parameter of the immersion cooling fluid. Section 2: Sensors and methods for measuring a heat transfer rate of an immersion cooling fluid are disclosed. In an aspect, a sensor is a hot-wire anemometer disposed within an immersion cooling fluid in at least one of a liquid phase, a froth phase, or a vapor phase. The hot-wire anemometer may be used to calculate a heat transfer coefficient for the immersion cooling fluid at a given level within an immersion cooling container. This calculated heat transfer coefficient may then be used to adjust an operational parameter of an immersion cooling system and / or computing hardware within the immersion cooling system.

Description

METHODS FOR FLUID CONTAMINATION MONITORING IN REAL TIME WITH OPTICSCROSS-REFERENCE TO RELATED APPLICATIONS

[0001] This Application claims the benefit of U.S. Provisional Patent Application 63 / 588,113, filed October 5, 2023, and entitled “Method for Fluid Contamination Monitoring in Real Time with Optics,” and U.S. Provisional Patent Application 63 / 608,638, filed December 11, 2023, and entitled “Multi-Domain Fluid Quality Monitoring For Two-Phase Immersion Cooling,” which are hereby incorporated by reference in their entireties.BACKGROUND

[0002] Section 1: As feature sizes and transistor sizes have decreased for integrated circuits (ICs) including chips and semiconductor dies, the amount of heat generated by a single chip, such as a microprocessor, has increased. Computing hardware that has traditionally been air cooled have evolved to chips needing more heat dissipation than can be provided by air alone. In some cases, immersion cooling of chips in a tank containing a coolant liquid is employed to maintain IC chips at appropriate operating temperatures.

[0003] One type of immersion cooling is two-phase immersion cooling, in which heat from a semiconductor die is high enough to boil the coolant liquid. The boiling creates a coolant-liquid vapor in the tank, which is condensed by cooling coils back to liquid form. Heat from the semiconductor dies can then be sunk into the liquid-to-gas and gas-to-liquid phase transitions of the coolant liquid. However, degradation or contamination of the cooling fluid can have negative effects on the computational hardware in the immersion cooling system. Spot checks on the immersion cooling fluid may be disruptive to immersion cooling system operation, hazardous to the health of a technician responsible for determining a state of the immersion cooling fluid, and may potentially introduce additional contaminants to the immersion cooling fluid.

[0004] Section 2: As feature sizes and transistor sizes have decreased for integrated circuits (ICs) including chips and semiconductor dies, the amount of heat generated by a single chip, such as a microprocessor, has increased. Computing hardware that has traditionally been air cooled have evolved to chips needing more heat dissipation than can be provided by air alone. In some cases, immersion cooling of chips in a tank containing a coolant liquid is employed to maintain IC chips at appropriate operating temperatures.

[0005] One type of immersion cooling is two-phase immersion cooling, in which heat from a semiconductor die is high enough to boil the coolant liquid. The boiling creates a coolant-liquid vapor in the tank, which is condensed by cooling coils back to liquid form. Heat from the semiconductor dies can then be sunk into the liquid-to-gas and gas-to-liquid phase transitions of the coolant liquid. However, components disposed at different locations within an immersion cooling tank may have varying levels of exposure to immersion cooling fluid, which may affect how efficiently heat is dissipated from those components. Accurate and cost-effective solutions for monitoring heat transfer in different immersion cooling phases are needed.SUMMARY

[0006] Section 1 : Immersion cooling systems have been developed as effective systems for the removal of waste heat from high-performance computing hardware. These systems may utilize dielectric liquids such as fluoroketones to provide a more efficient medium than air for the removal of waste heat while still insulating the immersed computing hardware and preventing signal loss or degradation. However, these liquids may break down, become less effective, or even become conductive over time due to contaminants introduced during installation, maintenance, and repair of immersed computing hardware.

[0007] State-of-the-art immersion cooling systems may require spot checks by a technician to determine a status of immersion cooling fluid within the system. However, this may result in exposure of the immersion cooling fluid to additional external contaminants including dust, dirt, oils, water, and atmospheric humidity. These external contaminants may build up over time and if not addressed, may cause damage or failure of components within the immersion cooling tank.

[0008] The present technology provides methods and sensors for monitoring a status of immersion cooling fluid in an immersion cooling system. The present technology may be directed toward a measurement medium and measurement signal generation device. Contamination may build up on the measurement medium over time and be detectable by emitting a visual or similar electromagnetic signal at the measurement medium and detecting one or more signals reflected from the measurement medium. The one or more reflected signals may carry information indicating a presence and amount of contamination on one or more surfaces of the measurement medium and may thereby provide an objective measurement of a status of immersion cooling fluid within an immersion cooling system.

[0009] In some aspects, the techniques described herein relate to a sensor for fluid contamination monitoring, the sensor including a measurement medium disposed on an immersion cooling container and in physical contact with a reservoir of immersion cooling fluid contained within the immersion cooling container; a measurement signal source configured to generate a firstmeasurement signal and emit the first measurement signal at the measurement medium; a detector configured to receive a second measurement signal; and a processor. The processor is communicatively coupled to the detector and the measurement signal source. The processor is further configured to determine a contamination parameter of the immersion cooling fluid based on a comparison of the first measurement signal and the second measurement signal.

[0010] In some aspects, the techniques described herein relate to a method for fluid contamination monitoring, the method including receiving, by a detector, a first measurement signal reflected from a measurement medium in physical contact with an immersion cooling fluid and comparing, by a processor, a characteristic of the first measurement signal to a characteristic of a second measurement signal emitted from a measurement signal source. The method further includes calculating, by the processor, a contamination parameter based on the step of comparing and altering, by the processor, a physical property of an immersion cooling system in response to the contamination parameter.

[0011] In some aspects, the techniques described herein relate to a sensor for fluid contamination monitoring, the sensor including a measurement medium disposed on a housing, the housing disposed within an immersion cooling container and in physical contact with a reservoir of immersion cooling fluid contained within the immersion cooling container. The sensor further includes a measurement signal source configured to generate a first measurement signal and emit the first measurement signal at the measurement medium. The sensor further includes a first detector disposed within the housing and configured to receive a second measurement signal and a second detector disposed externally to the housing and configured to receive a third measurement signal. The sensor further includes a processor, wherein the processor is communicatively coupled to the first detector, the second detector, and the measurement signal source. The processor is configured to determine a contamination parameter of the immersion cooling fluid based on a comparison of a plurality of the first measurement signal, the second measurement signal, and the third measurement signal.

[0012] In some aspects, the techniques described herein relate to a method for fluid contamination monitoring, the method including receiving, by a first detector disposed within a housing, a first measurement signal reflected from a measurement medium in physical contact with an immersion cooling fluid. The method further includes receiving, by a second detector disposed outside the housing, a second measurement signal reflected from the measurement medium and comparing, by a processor, respective wavelengths or respective signal strengths of the first measurement signal and the second measurement signal. The method further includes determining, by the processor, a contamination parameter of the immersion cooling fluid basedon the compared respective wavelengths or respective signal strengths and altering, by the processor, a physical property of an immersion cooling system in response to the contamination parameter.

[0013] All combinations of the foregoing concepts and additional concepts discussed in greater detail below (provided such concepts are not mutually inconsistent) are part of the inventive subject matter disclosed herein. In particular, all combinations of claimed subject matter appearing at the end of this disclosure are part of the inventive subject matter disclosed herein. The terminology used herein that also may appear in any disclosure incorporated by reference should be accorded a meaning most consistent with the particular concepts disclosed herein.

[0014] Section 2: Immersion cooling systems may enable high performance and high throughput computing hardware by providing efficient removal of waste heat generated by the computing hardware during operation. Immersion cooling fluid may have three phases within an immersion cooling system during operation: a liquid phase, a foam or froth phase, and a vapor phase. Each phase of immersion cooling fluid may have different heat transfer characteristics and provide varying levels of cooling for components.

[0015] The froth phase and vapor phase may provide less cooling as compared to a liquid phase. Accordingly, a computing hardware component exposed to immersion cooling fluid in a froth or vapor phase may need to operate at a lower frequency, voltage, current, processing power, etc., as compared to an identical computing hardware component immersed in immersion cooling liquid.

[0016] The inventors have recognized that precise monitoring of immersion cooling fluid levels within an immersion cooling system may allow for improved control of operational parameters of components disposed within an immersion cooling system such as an immersion cooling tank. For example, a network interface card (NIC) disposed within an immersion cooling froth may be able to operate at a higher data throughput rate than it would be if it was disposed within an immersion cooling vapor.

[0017] To enable this precise control of components within an immersion cooling system, the present disclosure is directed toward arrangements of hot-wire anemometers configured to detect a fluid level with greater precision than existing fluid level sensors. Further, these arrangements of hot-wire anemometers will enable estimates of heat transfer rates at various levels within an immersion cooling tank and thereby enable more precise estimates of maximum component operational parameters given a heat flux associated with those operational parameters.

[0018] In some aspects, the techniques described herein relate to a sensor for fluid quality management, the sensor including a hot-wire anemometer disposed at least partially within an immersion cooling fluid; a Wheatstone bridge electrically coupled to the hot-wire anemometer and configured to be electrically altered based on at least one of a current or a resistance across the hot-wire anemometer; a processor communicatively coupled to the Wheatstone bridge, the processor configured to calculate a heat transfer rate based on the current or the resistance.

[0019] In some aspects, the processor is configured to calculate the heat transfer rate based on an inverse relationship between the current and one or more temperatures.

[0020] In some aspects, the processor is configured to adjust an operational parameter of a component disposed at least partially within the immersion cooling fluid based on the heat transfer rate

[0021] In some aspects, the operational parameter includes at least one of a frequency, a power, a voltage, or a rate.

[0022] In some aspects, the immersion cooling fluid includes at least one of a liquid phase, a froth phase, or a vapor phase.

[0023] In some aspects, the techniques described herein relate to a method for fluid quality management, the method including measuring an electrical parameter of a sensor disposed at least partially within an immersion cooling fluid; determining a heat transfer rate associated with the immersion cooling fluid based on an inverse relationship between the electrical parameter of the sensor, an area of the sensor, and a temperature difference between the sensor and the immersion cooling fluid; controlling an operational parameter of a component disposed at least partially within the immersion cooling fluid based on the determined heat transfer rate.

[0024] In some aspects, the sensor includes a hot-wire anemometer.

[0025] In some aspects, the operational parameter includes at least one of a frequency, a voltage, or a rate.

[0026] In some aspects, the immersion cooling fluid includes at least one of a liquid phase, a froth phase, or a vapor phase.

[0027] All combinations of the foregoing concepts and additional concepts discussed in greater detail below (provided such concepts are not mutually inconsistent) are part of the inventive subject matter disclosed herein. In particular, all combinations of claimed subject matter appearing at the end of this disclosure are part of the inventive subject matter disclosed herein.The terminology used herein that also may appear in any disclosure incorporated by reference should be accorded a meaning most consistent with the particular concepts disclosed herein.BRIEF DESCRIPTION OF THE DRAWINGS

[0028] The skilled artisan will understand that the drawings primarily are for illustrative purposes and are not intended to limit the scope of the inventive subject matter described herein The drawings are not necessarily to scale; in some instances, various aspects of the inventive subject matter disclosed herein may be shown exaggerated or enlarged in the drawings to facilitate an understanding of different features In the drawings, like reference characters generally refer to like features (e.g., functionally similar and / or structurally similar elements).

[0029] FIG. 1.1 illustrates a sensor for detecting contamination in accordance with the present disclosure.

[0030] FIG. 1.2 illustrates a sensor for fluid contamination monitoring disposed within an immersion cooling container.

[0031] FIG. 1.3 depicts aspects of an immersion cooling system for dissipating heat from one or more semiconductor die packages via immersion cooling.

[0032] FIG. 2.1 depicts aspects of an immersion-cooling system for dissipating heat from one or more semiconductor die packages via immersion cooling.

[0033] FIG. 2.2 illustrates a sensor for fluid quality monitoring in accordance with the disclosure.

[0034] FIG. 2.3 illustrates an immersion cooling system including a sensor tree having a plurality of fluid quality sensors in accordance with the present technology.DETAILED DESCRIPTION

[0035] Section 1: FIG. 1.1 illustrates a sensor 1100 for detecting contamination in accordance with the present disclosure. Sensor 1100 may include a measurement medium 1130, measurement signal source 1140, and detector 1150. Measurement medium 1130 may be disposed on an immersion cooling container 1120. Immersion cooling container 1120 may contain a reservoir of immersion cooling fluid 1110, as well as computing hardware (not shown in FIG. 1.1, shown in greater detail in FIG. 1.3). Measurement medium 1130 may be disposed on immersion cooling container 1120 such that at least one surface of measurement medium 1130 physically contacts immersion cooling fluid 1110.

[0036] Measurement medium 1130 may optically couple or otherwise provide a path for one or more electromagnetic waves or similar signals to travel between an environment exterior to immersion cooling container 1120 and an environment interior to immersion cooling container 1120. For example, measurement medium 1130 may be at least partially transparent to light and allow light to be transmitted into and back out of immersion cooling container 1120. Contamination adhered to at least one surface of the measurement medium 1130 may at least partially reflect an electromagnetic signal (such as visible light) emitted into measurement medium 1130.

[0037] Measurement medium 1130 may include one or more of a glass (for example, borosilicate glass, quartz glass, soda lime glass, float glass, or the like), a plastic (for example, polycarbonate, acrylic, polyethylene terephthalate (PET), polyvinyl chloride (PVC), polyethylene (PE), polypropylene (PP), or the like), or other suitable material having a partial opacity. Measurement medium 1130 may be selected based on a compatibility with immersion cooling fluid, for example based on a chemical compatibility with a dielectric immersion cooling fluid such as fluoroketones, hydrocarbons, or oils.

[0038] Measurement medium 1130 may include at least one surface that is textured, roughened, treated, coated, or otherwise altered to promote nucleation or similar deposition of contaminants on the at least one surface so that the contaminants may be detected more easily. Texturing or roughening of at least one surface of measurement medium 1130 may include mechanical abrasion (e g. scratching, filing, and / or sanding the at least one surface with a harder material such as metal, sandpaper, diamond, or the like), chemical abrasion or etching, casting or molding measurement medium 1130 in a mold having a textured or roughened face, or the like. Coatings may include metals, organic coatings, inorganic coatings, oxides, silicates, silane, or the like.One or more surfaces may additionally or alternatively receive surface treatments such as plasma ionization or electron bombardment to introduce ions to the surface of the measurement medium 1130 and promote adhesion of contaminants to the surface. For example, at least one surface that is textured, roughened, treated, coated, or otherwise altered may be selected based on a physical contact between immersion cooling fluid 1110 and the at least one surface during operation of sensor 1100.

[0039] Measurement signal source 1140 may include one or more electromagnetic signal sources. Measurement signal source 1140 may include one or more of a laser, a lightbulb, a light-emitting diode (LED), a fluorescent light source, an electrical arc, a high-intensity discharge lamp, or any suitable electromagnetic signal sources. Measurement signal source 1140 may emit one or more measurement signals 1142a at one or more predetermined wavelengths orranges of wavelengths. For example, measurement signal source 1140 may emit one or more measurement signals 1142a having wavelengths between about 400 nm and about 600 nm, between about 200 nm and about 500 nm, between about 100 nm and about 350 nm, between about 300 nm and about 800 nm, between about 500 nm and about 900 nm, between about 300 nm and about 1000 nm, between about 350 nm and about 10 pm, between about 2 pm and about 8 pm, between about 5 pm and about 10 pm, or any suitable wavelength.

[0040] Measurement signal source 1140 may include a laser or other light source configured to emit one or more measurement signals 1142a having wavelengths in the visible light spectrum. For example, measurement signal source 1140 may include a laser configured to emit light between about 380 nm and about 450 nm, between about 450 nm and about 485 nm, between about 485 nm and about 500 nm, between about 500 nm and about 565 nm, between about 565 nm and about 590 nm, between about 590 nm and about 625 nm, and between about 625 nm and about 350 nm. Additionally or alternatively, measurement signal source 1140 may include a laser or other source configured to emit one or more measurement signals 1142a having wavelengths in the near infrared spectrum; for example, between about 350 nm and about 1100 nm.

[0041] Measurement signal source 1140 may have a power of about 1 W, about 3 W, about 5 W, less than 5 W, less than 2 W, less than 1 W, between about 0.1 W and about 1 W, between about 0.5 W and about 2 W, between about 0.1 W and about 5 W, less than 10 W, less than 20 W, or less than 100 W.

[0042] Sensor 1100 may include a detector 1150. Detector 1150 may be configured to receive, detect, and measure one or more one or more measurement signals 1142b. Detector 1150 may include one or more charge-coupled devices (CCDs), complementary metal-oxide semiconductor (CMOS) sensors, photodiodes, infrared sensors, or any suitable sensor for detecting electromagnetic signals having wavelengths within a range of about 100 nm to about 10 pm. Detector 1150 may be selected based on a desired resolution of wavelength, frequency, or signal strength. For example, detector 1150 may have a wavelength resolution of about ± 5% of a wavelength of measurement signal 1142a, about ± 2% of a wavelength of measurement signal 1142a, about ± 1% of a wavelength of measurement signal 1142a, about ± 0.1% of a wavelength of measurement signal 1142a, about ± 0.01% of a wavelength of measurement signal 1142a, about ± 0.001% of a wavelength of measurement signal 1142a, about ± 0.0001% of a wavelength emitted by measurement signal source 1140, or any suitable resolution.

[0043] Additionally or alternatively, detector 1150 may have a wavelength resolution of about ± 50 nm, about ± 20 nm, about ± 10 nm, about ± 1 nm, about ± 0.1 nm, about ± 0.01 nm, about ± 0.001 nm, or any suitable resolution.

[0044] Similarly, detector 1150 may have a signal strength resolution of about ± 5% of a signal strength of a measurement signal 1142a, about ± 2% of a signal strength of measurement signal 1142a, about ± 1% of a signal strength of measurement signal 1142a, about ± 0.1% of a signal strength of measurement signal 1142a, about ± 0.01% of a signal strength of measurement signal 1142a, about ± 0.001% of a signal strength of measurement signal 1142a, about ± 0.0001% of a signal strength of measurement signal 1142a, or any suitable resolution. Detector 1150 may be selected based on a type of measurement signal source 1140 and / or wavelength, frequency, or signal strength of one or more measurement signals 1142a and measurement signals 1142b.

[0045] Sensor 1100 may include a heater 1160 configured to increase a temperature of measurement medium 1130 and / or of immersion cooling fluid 1110 adjacent to measurement signal source 1140. Heater 1160 may increase a temperature of a portion of immersion cooling fluid 1110 proximal to measurement medium 1130 to or above a boiling temperature of immersion cooling fluid 1110. Heating a portion of immersion cooling fluid 1110 to or above the boiling temperature may promote accumulation or nucleation of contamination on measurement medium 1130 if contamination is present in immersion cooling fluid 1110. Heater 1160 may enable measurement of contamination when computing hardware within immersion cooling container 1120 is operating at powers too low to cause boiling or to otherwise enable accumulation or nucleation of contamination. Heater 1160 may be a resistance heater, a thermal testing vehicle, a film heater, a Kapton heater, a flexible heater, a ceramic heater, or integrated circuit specifically designed for heating measurement medium 1130.

[0046] Sensor 1100 may include processor 1170. Processor 1170 may be communicatively coupled to one or more of measurement signal source 1140, detector 1150, and / or heater 1160. Processor 1170 may control one or more functions or operations of measurement signal source 1140, detector 1150, and / or heater 1160. For example, processor 1170 may send a command signal to control measurement signal source 1140 to emit one or more measurement signals 1142a. Processor 1170 may receive one or more signal characteristics (for example, wavelength, frequency, signal strength, intensity, power, luminance, and the like) from detector 1150 and use the one or more signal characteristics to calculate a contamination parameter of immersion cooling fluid 1110.

[0047] For example, processor 1170 may be configured to compare measurement signal 1142a and measurement signal 1142b to determine that a contamination parameter such as particulate concentration, contamination thickness, contamination percentage by mass, contamination percentage by volume, estimated total contamination mass, estimated total contamination volume, etc., exceeds a threshold based on detector 1150 indicating a wavelength, frequency, orsignal strength of one or more measurement signals 1142b received by detector 1150. Processor 1170 may compare measurement signal 1142a and measurement signal 1142b to determine that a contamination level exceeds a threshold in response to a wavelength, frequency, or signal strength of measurement signal 1142b received by detector 1150 differing from the wavelength, frequency, or signal strength of measurement signal 1142a when it was emitted from measurement signal source 1140 by greater than a threshold.

[0048] In an embodiment, processor 1170 may be (or be part of) a tank controller such as a baseboard management controller (BMC), programmable logic controller (PLC), tank manager, control plane, or other controller configured to control one or more operations of an immersion cooling system in which sensor 1100 is disposed. Additionally or alternatively, processor 1170 may be communicatively coupled with a separate tank controller such as a BMC, PLC, control plane, tank manager, or other controller and provide immersion cooling fluid parameter information to the separate tank controller. Processor 1170 may alter a physical property of an immersion cooling system or a component of an immersion cooling system to which sensor 1100 is communicatively or optically coupled based on a determined contamination parameter. For example, processor 1170 may alter a voltage, current, power, temperature, processing speed, frequency, temperature, flow rate, rotational speed, memory state, bandwidth, latency, or similar physical property of an immersion cooling system or component of an immersion cooling system to which sensor 1100 is communicatively or optically coupled.

[0049] FIG. 1.2 illustrates a sensor for fluid contamination monitoring disposed within an immersion cooling container. Sensor 1200 may be partially or completely immersed in a reservoir of immersion cooling fluid 1210 contained within an immersion cooling container 1220 and may be configured to determine a level of contamination or status of immersion cooling fluid 1210.

[0050] Sensor 1200 may include sensor housing 1225. Sensor housing 1225 may provide a sealed volume inside of which several components of sensor 1200 are contained. Sensor housing 1225 may prevent immersion cooling fluid 1210 from interfering with or altering one or more emitted measurement signals 1242a and one or more received measurement signals 1242b within sensor housing 1225. Sensor housing 1225 may be made of a suitable material including glass, plastic, aluminum, stainless steel, copper, a reinforced epoxy such as glass-reinforced epoxy, other metal compatible with immersion cooling fluid 1210, or the like.

[0051] Sensor 1200 may include measurement medium 1230. Measurement medium 1230 may optically couple or otherwise provide a path for one or more electromagnetic waves or similar signals to travel between an environment interior to sensor housing 1225 and an environmentexterior to sensor housing 1225 (such as immersion cooling container 1220 and immersion cooling fluid 1210). Measurement medium 1230 may be disposed within immersion cooling container 1220 such that at least one surface of measurement medium 1230 physically contacts immersion cooling fluid 1210.

[0052] Measurement medium 1230 may include a prism configured to split a portion of an incident signal into two separate signals, e.g., split a portion of a first measurement signal into a first split signal and a second split signal. For example, measurement medium 1230 may be at least partially transparent to light and allow emitted measurement signal 1242a to be transmitted through measurement medium 1230 and split into measurement signal 1242b and measurement signal 1242c. Split measurement signals 1242b and 1242c may be received by detector 1250a and detector 1250b, respectively. Contamination adhered to at least one surface of the measurement medium 1230 may at least partially reflect an electromagnetic signal (such as visible light) emitted into measurement medium 1230. For example, one or more emitted measurement signals 1242a may include a beam of light, which may be split into one or more measurement signals 1242b and one or more measurement signals 1242c upon arriving at a surface of measurement medium 1230 on which contamination may have accumulated.

[0053] Measurement medium 1230 may include one or more of a glass (for example, borosilicate glass, quartz glass, soda lime glass, float glass, or the like), a plastic (for example, polycarbonate, acrylic, polyethylene terephthalate (PET), polyvinyl chloride (PVC), polyethylene (PE), polypropylene (PP), or the like), or other suitable material having a partial opacity. Measurement medium 1230 may be selected based on a compatibility with immersion cooling fluid, for example based on a chemical compatibility with a dielectric immersion cooling fluid such as fluoroketones, hydrocarbons, or oils.

[0054] Measurement medium 1230 may include at least one surface that is textured, roughened, treated, coated, or otherwise altered to promote nucleation or similar deposition of contaminants on the at least one surface so that the contaminants may be detected more easily. Texturing or roughening of at least one surface of measurement medium 1230 may include mechanical abrasion (e.g. scratching, filing, and / or sanding the at least one surface with a harder material such as metal, sandpaper, diamond, or the like), chemical abrasion or etching, casting or molding measurement medium 1230 in a mold having a textured or roughened face, or the like. Coatings may include metals, organic coatings, inorganic coatings, oxides, silicates, silane, or the like. One or more surfaces may additionally or alternatively receive surface treatments such as plasma ionization or electron bombardment to introduce ions to the surface of the measurement medium 1230 and promote adhesion of contaminants to the surface. For example, at least one surface thatis textured, roughened, treated, coated, or otherwise altered may be selected based on a physical contact between immersion cooling fluid 1210 and that at least one surface.

[0055] Measurement signal source 1240 may include one or more electromagnetic signal sources. Measurement signal source 1240 may include one or more of a laser, a lightbulb, a light-emitting diode (LED), a fluorescent light source, an electrical arc, a high-intensity discharge lamp, or any suitable electromagnetic signal sources. Measurement signal source 1240 may emit one or more measurement signals 1242a at one or more predetermined wavelengths or ranges of wavelengths. For example, measurement signal source 1240 may emit one or more measurement signals 1242a having wavelengths between about 400 nm and about 600 nm, between about 200 nm and about 500 nm, between about 100 nm and about 350 nm, between about 300 nm and about 800 nm, between about 500 nm and about 900 nm, between about 300 nm and about 1000 nm, between about 350 nm and about 10 pm, between about 2 pm and about 8 pm, between about 5 pm and about 10 pm, or any suitable wavelength.

[0056] Measurement signal source 1240 may include a laser or other light source configured to emit one or more measurement signals 1242a having wavelengths in the visible light spectrum. For example, measurement signal source 1240 may include a laser configured to emit light between about 380 nm and about 450 nm, between about 450 nm and about 485 nm, between about 485 nm and about 500 nm, between about 500 nm and about 565 nm, between about 565 nm and about 590 nm, between about 590 nm and about 625 nm, and between about 625 nm and about 350 nm. Additionally or alternatively, measurement signal source 1240 may include a laser or other source configured to emit one or more measurement signals 1242a having wavelengths in the near infrared spectrum; for example, between about 350 nm and about 1100 nm.

[0057] Measurement signal source 1240 may have a power of about 1 W, about 3 W, about 5 W, less than 5 W, less than 2 W, less than 1 W, between about 0.1 W and about 1 W, between about 0.5 W and about 2 W, between about 0.1 W and about 5 W, less than 10 W, less than 20 W, or less than 100 W.

[0058] Sensor 1200 may include detectors 1250a and 1250b. Detectors 1250a and 1250b may be configured to receive, detect, and measure one or more one or more received measurement signals 1242b and 1242c, respectively. Detectors 1250a and 1250b may include one or more charge-coupled devices (CCDs), complementary metal-oxide semiconductor (CMOS) sensors, photodiodes, infrared sensors, or any suitable sensor for detecting electromagnetic signals having wavelengths within a range of about 100 nm to about 10 pm. In an embodiment, detector 1250a may be disposed within sensor housing 1225 and detector 1250b may be disposed externally to sensor housing 1225. In an embodiment, 1250b may be disposed externally to measurementmedium 1230 with a predetermined separation or gap between detectors 1250b and measurement medium 1230. For example, a gap between detectors 1250b and measurement medium 1230 may be about 0.5 mm, about 1 mm, about 2 mm, between about 0.1 mm and about 5 mm, between about 1 cm and about 10 cm, between about 10 cm and about 1 m, between about 0.5 m and 5 m, or any suitable distance. Detectors 1250a and 1250b may be selected based on a desired resolution of wavelength, frequency, or signal strength.

[0059] For example, detectors 1250a and 1250b may have a wavelength resolution of about ± 5% of a wavelength of one or more emitted measurement signals 1242a, about ± 2% of a wavelength of one or more measurement signals 1242a, about ± 1% of a wavelength of one or more emitted measurement signals 1242a, about ± 0.1% of a wavelength of one or more emitted measurement signals 1242a, about ± 0.01% of a wavelength of one or more emitted measurement signals 1242a, about ± 0.001% of a wavelength of one or more measurement signals 1242a, about ± 0.0001% of a wavelength of one or more emitted measurement signals 1242a, or any suitable resolution.

[0060] Additionally or alternatively, detectors 1250a and 1250b may have a wavelength resolution of about ± 50 nm, about ± 20 nm, about ± 10 nm, about ± 1 nm, about ± 0.1 nm, about ± 0.01 nm, about ± 0.001 nm, or any suitable resolution.

[0061] Similarly, detectors 1250a and 1250b may have a signal strength resolution of about ± 5% of a signal strength of one or more emitted measurement signals 1242a, about ± 2% of a signal strength of one or more emitted measurement signals 1242a, about ± 1% of a signal strength of one or more emitted measurement signals 1242a, about ± 0.1% of a signal strength of one or more emitted measurement signals 1242a, about ± 0.01% of a signal strength of one or more emitted measurement signals 1242a, about ± 0.001% of a signal strength of one or more emitted measurement signals 1242a, about ± 0.0001% of a signal strength of one or more emitted measurement signals 1242a, or any suitable resolution. Detectors 1250a and 1250b may be selected based on a type of measurement signal source 1240, a wavelength of one or more measurement signals 1242a-c, and / or a signal strength of one or more measurement signals 1242a-c.

[0062] Sensor 1200 may include a heater 1260 configured to increase a temperature of measurement medium 1230 and / or of immersion cooling fluid 1210 adjacent to measurement signal source 1240. Heater 1260 may increase a temperature of a portion of an immersion cooling fluid 1210 proximal to measurement medium 1230 to or above a boiling temperature of immersion cooling fluid 1210. Heating a portion of an immersion cooling fluid 1210 may promote accumulation or nucleation of contamination on measurement medium 1230 ifcontamination is present in immersion cooling fluid 1210. Heater 1260 may enable measurement of contamination when computing hardware within immersion cooling container 1220 is operating at powers too low to cause boiling or to otherwise enable accumulation or nucleation of contamination. Heater 1260 may be a resistance heater, a thermal testing vehicle, a film heater, a Kapton heater, a flexible heater, a ceramic heater, or integrated circuit specifically designed for heating measurement medium 1230.

[0063] Sensor 1200 may include processor 1270. Processor 1270 may be communicatively coupled to one or more of measurement signal source 1240, detectors 1250a and 1250b, and / or heater 1260. Processor 1270 may control one or more functions or operations of measurement signal source 1240, detectors 1250a and 1250b, and / or heater 1260. For example, processor 1270 may send a command signal to control measurement signal source 1240 to emit one or more measurement signals 1242a. Processor 1270 may receive one or more signal characteristics (for example, wavelength, frequency, signal strength, intensity, power, luminance, and the like) from detectors 1250a and / or 1250b and use the one or more signal characteristics to calculate a contamination parameter of immersion cooling fluid 1210. For example, processor 1270 may be configured to determine that a contamination parameter exceeds a threshold based on receiving a detection signal indicating a wavelength, frequency, or signal strength of one or more received measurement signals 1242b and / or 1242c received by detector 1250a and 1250b, respectively.

[0064] In an embodiment, processor 1270 may be disposed outside of sensor housing 1225 and be (or be part of) a tank controller such as a baseboard management controller (BMC), programmable logic controller (PLC), tank manager, control plane, or other controller configured to control one or more operations of an immersion cooling system in which sensor 1200 is disposed. Additionally or alternatively, processor 1270 may be communicatively coupled with a separate tank controller such as a BMC, PLC, control plane, tank manager, or other controller and provide immersion cooling fluid parameter information to the separate tank controller.

[0065] Processor 1270 may be configured to determine that a contamination parameter such as particulate concentration, contamination percentage by mass, contamination percentage by volume, estimated total contamination mass, estimated total contamination volume, etc., exceeds a threshold in response to a wavelength, frequency, or signal strength of received measurement signal 1242b received by detector 1250a differing from the wavelength, frequency, or signal strength of emitted measurement signal 1242a when it was emitted from measurement signal source 1240.

[0066] Similarly, processor 1270 may determine that a contamination parameter such as particulate concentration, contamination percentage by mass, contamination percentage byvolume, estimated total contamination mass, estimated total contamination volume, etc., exceeds a threshold in response to a wavelength, frequency, or signal strength of measurement signal 1242c received by detector 1250b differing from the wavelength, frequency, or signal strength of emitted measurement signal 1242a when it was emitted from measurement signal source 1240.

[0067] Additionally or alternatively, processor 1270 may compare emitted measurement signal 1242a, received measurement signal 1242b, and / or received measurement signal 1242c to determine that a contamination parameter such as particulate concentration, contamination percentage by mass, contamination percentage by volume, estimated total contamination mass, estimated total contamination volume, etc., exceeds a threshold in response to a wavelength, frequency, or signal strength of received measurement signal 1242b received by detector 1250a differing from the wavelength, frequency, or signal strength of measurement signal 1242c received by detector 1250b by greater than a threshold amount.

[0068] Processor 1270 may alter a physical property of an immersion cooling system or a component of an immersion cooling system to which sensor 1200 is communicatively or optically coupled based on a determined contamination parameter. For example, processor 1170 may alter a voltage, current, power, temperature, processing speed, frequency, temperature, flow rate, rotational speed, memory state, bandwidth, latency, or similar physical property of an immersion cooling system or component of an immersion cooling system (such as a component of immersion cooling system 300) to which sensor 1200 is communicatively or optically coupled.

[0069] Further details and examples of fluid contamination sensors may be found in U.S. Provisional Application No. 63 / 512,575, filed on July 7, 2023 and entitled, “Fluid Sensor for Immersion-Cooling Systems,” and U.S. Provisional Application No. 63 / 516,148, filed on July 31, 2023 and entitled, “DI-ELECTRIC MONITORING OF IMMERSION FLUID DURING COOLING OPERATION,” both of which are incorporated by reference herein in their entirety.

[0070] FIG. 1.3 depicts aspects of an immersion cooling system 1300 for dissipating heat from one or more semiconductor die packages 1305 via immersion cooling. Each package 1305 can include one or more semiconductor dies that produce heat when the system is in operation. The immersion cooling system 1300 in the illustrated example of FIG. 1.3 is a two-phase immersion cooling system, though the invention may also be implemented in a single-phase immersion cooling system.

[0071] The immersion cooling system 1300 includes a container such as tank 1320 filled, at least in part, with immersion cooling liquid 1364. The immersion cooling system 1300 can further include at least one chiller 1380 that flows a heat-transfer fluid through at least one condensercoil 1370 that is disposed in the tank 1320 and headspace 1308. Condenser coil 1370 and chiller 1380 may be part of a heat exchanger. The packages 1305 can be mounted on one or more printed circuit boards (PCBs) 1357 that are immersed, at least in part, in the immersion cooling liquid 1364. Immersion-cooling system 1300 may further include a filter 1375 disposed adjacent to the tank 1320.

[0072] Filter 1375 may include a filtration media, a housing, and a pump configured to force immersion cooling liquid 1364 through filter 1375 to remove contaminants, particulates, or other impurities that may be added to immersion cooling liquid 1364 during use. Filter 1375 may be housed outside of tank 1320 while being in fluidic communication with immersion cooling liquid 1364 in tank 1320. Alternatively, filter 1375 may be submerged within immersion cooling liquid 1364 inside of tank 1320.

[0073] Immersion cooling liquid 1364 may be a hydrocarbon, a fluoroketone, an oil, or a similar dielectric liquid that will act as an insulator while simultaneously transferring heat from package 1305 more efficiently than air. An example of immersion cooling liquid 1364 is Novec™ 649 produced by 3M™. An exemplary immersion cooling liquid 1364 used in accordance with embodiments of the present invention may have a dielectric constant baseline value of about 1.8- 2 at a frequency of about 1 kHz.

[0074] In an embodiment of the invention, immersion cooling liquid 1364 may be considered unacceptably contaminated if the dielectric constant and / or dielectric loss tangent of immersion cooling fluid being used in an immersion cooling system 1300 differs by a threshold amount as compared to unused or pure immersion cooling liquid 1364. For example, immersion cooling liquid 1364 may be considered unacceptably contaminated or degraded if the dielectric constant and / or dielectric loss tangent differs by a threshold of 10% or more as compared to unused or pure immersion cooling liquid 1364. In an embodiment, a dielectric constant and / or dielectric loss tangent variation threshold may be 20%, 15%, 5%, 3%, 1%, or any suitable threshold.

[0075] Contamination of the immersion cooling liquid 1364 and resulting changes to dielectric constant and / or dielectric loss tangent may alter or negatively impact operation of components within immersion cooling liquid 1364 including semiconductor die(s) 1350. An altered dielectric constant and / or dielectric loss tangent may result in undesirable cross-talk between components on a PCB, additional noise or reduction in signal strength transmitted along exposed wires of a PCB or semiconductor die(s) 1350 submerged in immersion fluid, and / or signal dissipation through the immersion cooling liquid 1364. Signal loss may be severe enough that two elements may be effectively represented as being separated by an open circuit despite being physically connected. In an embodiment, a dielectric constant and / or dielectric loss tangent variationthreshold may be selected based on an observed or inferred effect on one or more submerged semiconductor die(s) 1350. For example, an increase in PCIe bit error rate above an error rate baseline may be correlated with an increase in dielectric constant and / or dielectric loss tangent above a dielectric constant and / or dielectric loss tangent baseline. Accordingly, operation of semiconductor die(s) 1350 may be throttled or suspended when a dielectric constant and / or dielectric loss tangent of immersion cooling liquid 1364 exceeds a predetermined threshold.

[0076] Changes to dielectric constant and / or dielectric loss tangent may be caused by contaminants within immersion cooling liquid 1364. In some cases, changes to dielectric constant and / or dielectric loss tangent may be reversed by filtering the contaminants from immersion cooling liquid 1364. In some embodiments, upon detecting an increase in dielectric constant and / or dielectric loss tangent of immersion cooling liquid 1364, controller 1302 may instruct filter 1375 to increase filtration throughput or notify a user that an immersion cooling liquid 1364 filtration media may need to be replaced. If a dielectric constant and / or dielectric loss tangent exceeds a predetermined threshold, controller 1302 may throttle or shut down one or more semiconductor die(s) 1350, generate a notification that immersion cooling liquid 1364 should be replaced, trigger an alarm, etc.

[0077] The illustrated example of FIG. 1.3 is not intended to be to scale. The immersion cooling system 1300 may house and provide immersion cooling liquid 1364 to tens, hundreds, or even thousands of packages 1305. In some cases, the immersion cooling system 1300 can be small (e g., the size of a floor unit air conditioner, approximately 1 meter high, 0.5 meter width, 0.5 meter depth or length). In some implementations, the immersion cooling system can be large (e g., the size of a van or larger, approximately 2.5 meters high, 2.5 meters width, 4 meters depth or length).

[0078] The immersion cooling system 1300 can also include a controller 1302 (e.g., a microcontroller, programmable logic controller (PLC), microprocessor, field-programmable gate array, logic circuitry, memory, or some combination thereof) to manage system operation. Controller 1302 can perform various system functions such as monitoring temperatures of system components, cooling fluid level, tank access, chiller operation etc. The controller 1302 can further issue commands to control system operation such as executing a start-up sequence, executing a shut-down sequence, assigning workloads among the packages, changing cooling fluid level, changing the temperature of the heat-transfer fluid circulated by the chiller 1380, etc. In some implementations, the controller 1302 can include (or itself be) a baseboard management controller (BMC) 1304. That is, the BMC 1304 may monitor and control all aspects of system operation for the immersion cooling system 1300 in addition to monitoring and controllingworkloads of the semiconductor dies 1350 in the packages 1305 cooled by the system. The immersion cooling system 1300 can also include a network interface controller (NIC) 1303 to allow the system to communicate over a network, such as a local area network or wide area network. The immersion cooling system 1300 can further include a fluid sensor array 1390 having a plurality of fluid sensors 1310. Fluid sensors 1310 may include one or more leak detection sensors at least partially submerged in immersion cooling liquid 1364.

[0079] The semiconductor die(s) 1350 and can be mounted on and attached to a printed circuit board (PCB) 1355 (sometimes referred to as a substrate) in device package 1305. The package 1305 can be made commercially available as an off-the-shelf (OTS) product. The package 1305 can be used for single-phase or two-phase immersion cooling of at least one semiconductor die 1350, such as a microprocessor (e.g., a central processing unit (CPU) and / or graphics processing unit (GPU)), voltage regulator (VR), high bandwidth memory (HBM), a digital signal processing (DSP) die, an application-specific integrated circuit (ASIC), field-programmable gate array (FPGA), and / or other densely patterned semiconductor die.

[0080] In the two-phase immersion cooling system 1300 of FIG. 1.3, heat flows from the semiconductor die 1350 where it is generated into the heat spreader 1352. The heat spreader 1352 is in thermal contact with an immersion cooling liquid 1364 that can flow over and extract heat from the heat spreader 1352. The amount of heat delivered by the heat spreader 1352 to the immersion cooling liquid 1364 is enough to boil the immersion cooling liquid 1364 that contacts the heat spreader 1352 (creating bubbles 1365 and potentially creating froth 1367 when bubbles 1365 reach the surface of immersion cooling liquid 1364). The vapor 1366 from the boiled immersion cooling liquid 1364 can be cooled and condensed back to liquid droplets 1368, for example, by the condenser coil 1370. The heat-transfer fluid, such as chilled water, from the chiller 1380 can be circulated through the condenser coil 1370 to lower the temperature of the condenser coil 1370 below the condensation point in the headspace 1308 of the tank 1320. As a result, vapor 1366 condenses on exterior surfaces of the condenser coil 1370 and liquid droplets 1368 from the condensed vapor can drip and / or flow back to the immersion cooling liquid 1364. Although a single condenser coil 1370 is depicted in FIG. 1.3, there can be a plurality of condenser coils 1370 in tank 1320 to condense the vapor 1366 into droplets. Some or all of the condenser coils 1370 may or may not be located directly over the PCBs 1357. Instead, the condenser coil(s) 1370 can be located near one or more walls of the tank 1320, such that the condenser coil(s) 1370 are not directly over the PCBs 1357 on which the packages 1305 are mounted.

[0081] To improve thermal performance in two-phase immersion cooling system 1300, the heat spreader 1352 can include a boiling enhancement coating (BEC) on at least one surface. The BEC can be formed from copper or a copper alloy and can be porous, for example, though BECs can take various forms. In some cases, the BEC is a micro porous copper coating having a thickness from approximately or exactly 50 microns to 1300 microns thick (which may be produced by electroplating and / or etching). In some implementations, the BEC comprises a mesh copper layer bonded (e g., via resistance heating) to at least an outer surface of the heat spreader 1352. In some cases, the BEC is applied as particulates to at least one smooth surface of the heat spreader 1352 and then subsequently sintered to adhere to one another and to the heat spreader 1352. The BEC provides an improved surface area to contact the immersion cooling liquid 1364 and can increase the heat transfer coefficient from the heat spreader 1352 to the immersion cooling liquid 1364 by up to a factor of 15 versus a smooth surface on the heat spreader 1352. Accordingly, BECs can increase thermal conductivity to, and accelerate the boiling of, the immersion cooling liquid 1364.

[0082] Section 2: FIG. 2.1 depicts aspects of an immersion-cooling system 2100 for dissipating heat from one or more semiconductor die packages 2105 via immersion cooling. Each package 2105 can include one or more semiconductor dies that produce heat when the system is in operation. The immersion-cooling system 2100 in the illustrated example of FIG. 2.1 is a two- phase immersion-cooling system, though the invention may also be implemented in a singlephase immersion-cooling system.

[0083] The immersion-cooling system 2100 includes a container such as tank 2120 filled, at least in part, with immersion cooling liquid 2164. The immersion-cooling system 2100 can further include at least one chiller 2180 that flows a heat-transfer fluid through at least one condenser coil 2170 that is disposed in the tank 2120 and headspace 2108. Condenser coil 2170 and chiller 2180 may be part of a heat exchanger. The packages 2105 can be mounted on one or more printed circuit boards (PCBs) 2157 that are immersed, at least in part, in the immersion cooling liquid 2164. Immersion-cooling system 2100 may further include a filter 2175 disposed adjacent to the tank 2120.

[0084] Filter 2175 may include a filtration media, a housing, and a pump configured to force immersion cooling liquid 2164 through filter 2175 to remove contaminants, particulates, or other impurities that may be added to immersion cooling liquid 2164 during use. Filter 2175 may be housed outside of tank 2120 while being in fluidic communication with immersion cooling liquid 2164 in tank 2120. Alternatively, filter 2175 may be submerged within immersion cooling liquid 2164 inside of tank 2120.

[0085] Immersion cooling liquid 2164 may be a hydrocarbon, a fluoroketone, an oil, or a similar dielectric liquid that will act as an insulator while simultaneously transferring heat from package 2105 more efficiently than air. An example of immersion cooling liquid 2164 is Novec™ 649 produced by 3M™. An exemplary immersion cooling liquid 2164 used in accordance with embodiments of the present invention may have a dielectric constant baseline value of about 1.8- 2 at a frequency of about 1 kHz.

[0086] In an embodiment of the invention, immersion cooling liquid 2164 may be considered unacceptably contaminated if the dielectric constant and / or dielectric loss tangent of immersion cooling fluid being used in an immersion-cooling system 2100 differs by a threshold amount as compared to unused or pure immersion cooling liquid 2164. For example, immersion cooling liquid 2164 may be considered unacceptably contaminated or degraded if the dielectric constant and / or dielectric loss tangent differs by a threshold of 10% or more as compared to unused or pure immersion cooling liquid 2164. In an embodiment, a dielectric constant and / or dielectric loss tangent variation threshold may be 20%, 15%, 5%, 3%, 1%, or any suitable threshold.

[0087] Contamination of the immersion cooling liquid 2164 and resulting changes to dielectric constant and / or dielectric loss tangent may alter or negatively impact operation of components within immersion cooling liquid 2164 including semiconductor die(s) 2150. An altered dielectric constant and / or dielectric loss tangent may result in undesirable cross-talk between components on a PCB, additional noise or reduction in signal strength transmitted along exposed wires of a PCB or semiconductor die(s) 2150 submerged in immersion fluid, and / or signal dissipation through the immersion cooling liquid 2164. Signal loss may be severe enough that two elements may be effectively represented as being separated by an open circuit despite being physically connected. In an embodiment, a dielectric constant and / or dielectric loss tangent variation threshold may be selected based on an observed or inferred effect on one or more submerged semiconductor die(s) 2150. For example, an increase in PCIe bit error rate above an error rate baseline may be correlated with an increase in dielectric constant and / or dielectric loss tangent above a dielectric constant and / or dielectric loss tangent baseline. Accordingly, operation of semiconductor die(s) 2150 may be throttled or suspended when a dielectric constant and / or dielectric loss tangent of immersion cooling liquid 2164 exceeds a predetermined threshold.

[0088] Changes to dielectric constant and / or dielectric loss tangent may be caused by contaminants within immersion cooling liquid 2164. In some cases, changes to dielectric constant and / or dielectric loss tangent may be reversed by filtering the contaminants from immersion cooling liquid 2164. In some embodiments, upon detecting an increase in dielectric constant and / or dielectric loss tangent of immersion cooling liquid 2164, controller 2102 mayinstruct filter 2175 to increase filtration throughput or notify a user that an immersion cooling liquid 2164 filtration media may need to be replaced. If a dielectric constant and / or dielectric loss tangent exceeds a predetermined threshold, controller 2102 may throttle or shut down one or more semiconductor die(s) 2150, generate a notification that immersion cooling liquid 2164 should be replaced, trigger an alarm, etc.

[0089] The illustrated example of FIG. 2.1 is not intended to be to scale. The immersion-cooling system 2100 may house and provide immersion cooling liquid 2164 to tens, hundreds, or even thousands of packages 2105. In some cases, the immersion-cooling system 2100 can be small (e.g., the size of a floor unit air conditioner, approximately 1 meter high, 0.5 meter width, 0.5 meter depth or length). In some implementations, the immersion-cooling system can be large (e.g., the size of a van or larger, approximately 2.5 meters high, 2.5 meters width, 4 meters depth or length).

[0090] The immersion-cooling system 2100 can also include a controller 2102 (e.g., a microcontroller, programmable logic controller (PLC), microprocessor, field-programmable gate array, logic circuitry, memory, or some combination thereof) to manage system operation. Controller 2102 can perform various system functions such as monitoring temperatures of system components, cooling fluid level, tank access, chiller operation etc. The controller 2102 can further issue commands to control system operation such as executing a start-up sequence, executing a shut-down sequence, assigning workloads among the packages, changing cooling fluid level, changing the temperature of the heat-transfer fluid circulated by the chiller 2180, etc. In some implementations, the controller 2102 can include (or itself be) a baseboard management controller (BMC) 2104. That is, the BMC 2104 may monitor and control all aspects of system operation for the immersion-cooling system 2100 in addition to monitoring and controlling workloads of the semiconductor dies 2150 in the packages 2105 cooled by the system. The immersion-cooling system 2100 can also include a network interface controller (NIC) 2103 to allow the system to communicate over a network, such as a local area network or wide area network. The immersion-cooling system 2100 can further include a fluid sensor array 2190 having a plurality of fluid sensors 2110. Fluid sensors 2110 may include one or more leak detection sensors at least partially submerged in immersion cooling liquid 2164.

[0091] The semiconductor die(s) 2150 and can be mounted on and attached to a printed circuit board (PCB) 155 (sometimes referred to as a substrate) in device package 2105. The package 2105 can be made commercially available as an off-the-shelf (OTS) product. The package 2105 can be used for single-phase or two-phase immersion cooling of at least one semiconductor die 2150, such as a microprocessor (e.g., a central processing unit (CPU) and / or graphics processingunit (GPU)), voltage regulator (VR), high bandwidth memory (HBM), a digital signal processing (DSP) die, an application-specific integrated circuit (ASIC), field-programmable gate array (FPGA), and / or other densely patterned semiconductor die.

[0092] In the two-phase immersion-cooling system 2100 of FIG. 2.1, heat flows from the semiconductor die 2150 where it is generated into the heat spreader 2152. The heat spreader 2152 is in thermal contact with an immersion cooling liquid 2164 that can flow over and extract heat from the heat spreader 2152. The amount of heat delivered by the heat spreader 2152 to the immersion cooling liquid 2164 is enough to boil the immersion cooling liquid 2164 that contacts the heat spreader 2152 (creating bubbles 2165 and potentially creating immersion cooling froth 2167 when bubbles 2165 reach the surface of immersion cooling liquid 2164). The immersion cooling vapor 2166 from the boiled immersion cooling liquid 2164 can be cooled and condensed back to liquid droplets 2168, for example, by the condenser coil 2170. The heat-transfer fluid, such as chilled water, from the chiller 2180 can be circulated through the condenser coil 2170 to lower the temperature of the condenser coil 2170 below the condensation point in the headspace 2108 of the tank 2120. As a result, immersion cooling vapor 2166 condenses on exterior surfaces of the condenser coil 2170 and liquid droplets 2168 from the condensed vapor can drip and / or flow back to the immersion cooling liquid 2164. Although a single condenser coil 2170 is depicted in FIG. 2.1, there can be a plurality of condenser coils 2170 in tank 2120 to condense the immersion cooling vapor 2166 into droplets. Some or all of the condenser coils 2170 may or may not be located directly over the PCBs 2157. Instead, the condenser coil(s) 2170 can be located near one or more walls of the tank 2120, such that the condenser coil(s) 2170 are not directly over the PCBs 2157 on which the packages 2105 are mounted.

[0093] To improve thermal performance in two-phase immersion-cooling system 2100, the heat spreader 2152 can include a boiling enhancement coating (BEC) on at least one surface. The BEC can be formed from copper or a copper alloy and can be porous, for example, though BECs can take various forms. In some cases, the BEC is a micro porous copper coating having a thickness from approximately or exactly 50 microns to 100 microns thick (which may be produced by electroplating and / or etching). In some implementations, the BEC comprises a mesh copper layer bonded (e.g., via resistance heating) to at least an outer surface of the heat spreader 2152. In some cases, the BEC is applied as particulates to at least one smooth surface of the heat spreader 2152 and then subsequently sintered to adhere to one another and to the heat spreader 2152. The BEC provides an improved surface area to contact the immersion cooling liquid 2164 and can increase the heat transfer coefficient from the heat spreader 2152 to the immersion cooling liquid 2164 by up to a factor of 15 versus a smooth surface on the heatspreader 2152. Accordingly, BECs can increase thermal conductivity to, and accelerate the boiling of, the immersion cooling liquid 2164.

[0094] FIG. 2.2 illustrates a sensor 2200 for fluid quality monitoring in accordance with the disclosure. The sensor may include a hot-wire anemometer disposed at least partially within an immersion cooling fluid (such as immersion cooling liquid 2164, immersion cooling vapor 2166, immersion cooling froth 2167, etc.) and electrically coupled to a Wheatstone bridge 2210. A hotwire anemometer 2220 may include a wire made of a conductive material such as platinum or copper and connected to a plurality of electrodes. The electrodes may be connected to the Wheatstone bridge 2210. The sensor may further include a processor 2230 configured to determine one or more of a current, a voltage, a resistance, a temperature, an operational state of an immersion cooling system, an operational state of one or more components within an immersion cooling system, an operational parameter (for example, frequency, voltage, current, impedance, bandwidth, latency, data transfer rate, temperature, power consumption, and the like) of one or more components within an immersion cooling system, and the like.

[0095] The processor 2230 may be further configured to perform one or more calculations corresponding to one or more physical parameters of an immersion cooling system. For example, the processor 2230 may be configured to calculate a heat transfer coefficient h as follows:Where Awis the projected wire surface area, Twis the temperature of the wire, Tr is the temperature of the immersion cooling fluid in which the sensor is at least partially disposed, I is the current flowing across the wire, and R4 is the resistance (or impedance if a time-varying component is present) of the hot-wire anemometer 2220. A heat transfer coefficient for immersion cooling liquid 2164 may be about 20,000 W / m2K, between about 15,000 W / m2K to about 30,000 W / m2K, between about 10,000 W / m2K to about 40,000 W / m2K, or any suitable subrange. A heat transfer coefficient for immersion cooling froth 2167 may be about 5,000 W / m2K, between about 2,000 W / m2K and about 12,000 W / m2K, between about 1,000 W / m2K and about 15,000 W / m2K, between about 50 W / m2K and about 5,000 W / m2K, or any suitable subrange. A heat transfer coefficient for immersion cooling vapor may be about 30 W / m2K, between about 20 W / m2K and about 50 W / m2K, between about 10 W / m2K and about 80 W / m2K, between about 1 W / m2K and about 100 W / m2K, or any suitable subrange.

[0096] In some implementations, a Wheatstone bridge 2210 may be used to determine a voltage, resistance, or heat flux across a hot-wire anemometer 2220 as depicted in FIG. 2.2. The Wheatstone bridge 2210 may be electrically altered in response to at least one of a current, avoltage, a resistance, a capacitance, or other suitable electrical parameter of the hot-wire anemometer 2220. For example, a voltage, current, or resistance value across a portion of the Wheatstone bridge 2210 may be altered in response to at least one of a current, a voltage, a resistance, a capacitance, or other suitable electrical parameter of the hot-wire anemometer 2220.

[0097] The Wheatstone bridge 2210 can be operated to sense an unknown impedance (R4 in this example). For the example of FIG. 2.2, real resistances are used though impedances (which can include capacitance and inductance) can be used more generally. In a Wheatstone bridge 2210, three of the four resistances Ri, R2, R3 (or impedances) for resistive elements, are known, whereas the fourth resistance R4 (or impedance) for the variable resistive element is unknown and to be determined. A current source, which can be direct current (DC) or alternating current (AC), drives currents through the two circuit branches of the Wheatstone bridge 2210. One way to operate the Wheatstone bridge 2210 is to select Ri = R2 = R3 = R. If R4 = R, then the Wheatstone bridge 2210 is balanced and a voltage at voltage measurement node VA equals a voltage at voltage measurement node VB. Deviations of R4 from R results in VA t VB. Measuring the voltage between measurement nodes VA and VB, (which can be done with circuitry of the sensor semiconductor die 150) can then indicate the difference of R4 for the variable resistive element from R. Solving straightforward circuit equations can provide the value of R4 for the resistive element.

[0098] When the Wheatstone bridge 2210 is implemented in the impedance sensor, resistive elements can be implemented with integrated or discrete resistors, for example. The variable resistive element may comprise, at least in part, an aspect (liquid, froth, vapor) of the immersion cooling liquid 2164 and its associated conductance. In that regard, the variable resistive element can be implemented as a pair of separated electrodes to which the hot wire anemometer is connected. The hot wire anemometer may be exposed to immersion cooling fluid (e.g., immersion cooling liquid 2164, immersion cooling froth 2167, immersion cooling vapor 2166) and can be bridged by the coolant liquid, froth, and vapor to provide conductance between the electrodes. In some implementations, the electrodes can be connected by a material that is adapted to absorb or wick in coolant liquid, froth, and vapor to change conductance of the material. The conductance of the variable resistive element (and therefore resistance R4 and impedance) can be determined, at least in part, by the state of the immersion cooling liquid 2164 contacting the electrodes and contacting the material (if present). The conductance of the variable resistive element may also be determined in part by the unwetted conductance of the material. States of the immersion cooling liquid 2164 include liquid, liquid with bubbles (when boiling), froth, vapor, and no vapor (air or other gasses only).

[0099] FIG. 2.3 illustrates an immersion cooling system 2300 including a sensor tree having a plurality of sensors, such as sensors S1-S9, in accordance with the present technology. Each of sensors S1-S9 may be or include a hot-wire anemometer. Each of sensors S1-S9 may be similar to or the same as sensor 20 and may be disposed at least partially within an immersion cooling fluid. The immersion cooling fluid may be in a phase including at least one of a liquid phase, a froth phase, and a vapor phase. One or more of sensors S1-S9 may be disposed at least partially within immersion cooling fluid of each phase. Immersion cooling system 300 may further include a baseboard management controller (BMC) communicatively coupled to additional components of immersion cooling system 2300 including sensor tree, sensors S1-S9, NIC, memory module, and / or servers. Each of sensors S1-S9 may be disposed at a predetermined height and / or location within the immersion cooling container. Each location may be used by the BMC or other controller to determine and control one or more operational parameters associated with immersion cooling system 2300.

[0100] Immersion cooling system 2300 may include an immersion cooling container configured to contain immersion cooling fluid as well as one or more components. The one or more components may include computing hardware such as one or more servers, logic ICs, GPUs, CPU head nodes, Al accelerators, three-dimensional integrated circuit (3DIC) stacks, memory modules, and the like. The one or more components may additionally or alternatively include components such as one or more network interface cards (NICs), switches, optical cables, bus bars, sensors, or similar peripheral components.

[0101] A memory module may be an integrated circuit (IC) configured to store data and may include a dynamic random access memory (DRAM) module, a static random access memory (SRAM) module, a flash memory module, a solid-state drive (SSD), a non-volatile random access memory (NVRAM) module, a read-only memory (ROM) module (such as a floating-gate ROM, erasable programmable read-only memory (EPROM), electrically erasable programmable read-only memory (EEPROM), one-time programmable ROM (OTPROM), or the like), or any suitable type of memory module.

[0102] Computing hardware may include one or more microprocessors (e.g., a central processing unit (CPUs) and / or graphics processing units (GPUs)), voltage regulators (VR), high bandwidth memory (HBM), digital signal processing (DSP) dies, an artificial intelligence (Al) accelerators, application-specific integrated circuits (ASICs), field-programmable gate arrays (FPGAs), and / or other densely patterned semiconductor die or logic IC.

[0103] A BMC may include one or more processors configured to receive signals and / or data from components to which it is communicatively coupled and control one or moreoperational parameters of immersion cooling system 2300 based on received signals and / or calculations.

[0104] A BMC may calculate a heat transfer rate of an immersion cooling fluid at a particular location within an immersion cooling container (e.g., a height above a floor of the immersion cooling container) based on one or more signals from a sensor tree and / or any of sensors S1-S9. For example, a BMC may receive one or more current measurement signals or resistance measurement signals from any one or multiple of sensors S1-S9 and calculate a heat transfer rate at the location of the respective sensor based on the one or more current measurement signals or resistance measurement signals. A BMC may receive one or more temperature measurement signals from any one or multiple of sensors S1-S9 and may calculate a heat transfer rate for a location of a given sensor based on an inverse relationship between one or more current measurement signals and the one or more temperature measurement signals as described with reference to FIG. 2.2.

[0105] In an embodiment, a BMC may be configured to adjust or control an operational parameter of a component disposed at least partially within the immersion cooling fluid based on the heat transfer rate. For example, if a heat transfer rate is calculated as being below a threshold value within an immersion cooling liquid in the immersion cooling container, the BMC may command one or more servers to reduce a computational frequency, which may reduce the power drawn by the servers. This may result in the one or more servers generating less waste heat in accordance with the lower heat transfer rate of the immersion cooling liquid, thus reducing the risk of degrading the immersion cooling liquid and potentially damaging one or more components disposed within the immersion cooling fluid and / or immersion cooling container.

[0106] An operational parameter may include a frequency (e.g., a computational frequency), a power (e.g., a power drawn by one or more components disposed within the immersion cooling container or a power input into the one or more components), a voltage (e.g., a voltage drawn by one or more components disposed within the immersion cooling container, a voltage across a bus bar within the immersion cooling container, a power supply voltage, etc.), a rate (e.g., a transfer rate of data to and from one or more servers, a sampling rate, a query rate, a flow rate, etc.), a pressure (e.g., a pressure within the immersion cooling container), or any suitable operational parameter.Conclusion

[0107] While various inventive embodiments have been described and illustrated herein, those of ordinary skill in the art will readily envision a variety of other means and / or structuresfor performing the function and / or obtaining the results and / or one or more of the advantages described herein, and each of such variations and / or modifications is deemed to be within the scope of the inventive embodiments described herein. More generally, those skilled in the art will readily appreciate that all parameters, dimensions, materials, and configurations described herein are meant to be exemplary and that the actual parameters, dimensions, materials, and / or configurations will depend upon the specific application or applications for which the inventive teachings is / are used. Those skilled in the art will recognize or be able to ascertain using no more than routine experimentation, many equivalents to the specific inventive embodiments described herein. It is, therefore, to be understood that the foregoing embodiments are presented by way of example only and that, within the scope of the appended claims and equivalents thereto, inventive embodiments may be practiced otherwise than as specifically described and claimed. Inventive embodiments of the present disclosure are directed to each individual feature, system, article, material, kit, and / or method described herein. In addition, any combination of two or more such features, systems, articles, materials, kits, and / or methods, if such features, systems, articles, materials, kits, and / or methods are not mutually inconsistent, is included within the inventive scope of the present disclosure.

[0108] Also, various inventive concepts may be embodied as one or more methods, of which an example has been provided. The acts performed as part of the method may be ordered in any suitable way. Accordingly, embodiments may be constructed in which acts are performed in an order different than illustrated, which may include performing some acts simultaneously, even though shown as sequential acts in illustrative embodiments.

[0109] All definitions, as defined and used herein, should be understood to control over dictionary definitions, definitions in documents incorporated by reference, and / or ordinary meanings of the defined terms.

[0110] The indefinite articles “a” and “an,” as used herein in the specification and in the claims, unless clearly indicated to the contrary, should be understood to mean “at least one.”

[0111] The phrase “and / or,” as used herein in the specification and in the claims, should be understood to mean “either or both” of the elements so conjoined, i.e., elements that are conjunctively present in some cases and disjunctively present in other cases. Multiple elements listed with “and / or” should be construed in the same fashion, i.e., “one or more” of the elements so conjoined. Other elements may optionally be present other than the elements specifically identified by the “and / or” clause, whether related or unrelated to those elements specifically identified. Thus, as a non-limiting example, a reference to “A and / or B”, when used in conjunction with open-ended language such as “comprising” can refer, in one embodiment, to Aonly (optionally including elements other than B); in another embodiment, to B only (optionally including elements other than A); in yet another embodiment, to both A and B (optionally including other elements); etc.

[0112] As used herein in the specification and in the claims, “or” should be understood to have the same meaning as “and / or” as defined above. For example, when separating items in a list, “or” or “and / or” shall be interpreted as being inclusive, i.e., the inclusion of at least one, but also including more than one, of a number or list of elements, and, optionally, additional unlisted items. Only terms clearly indicated to the contrary, such as “only one of’ or “exactly one of,” or, when used in the claims, “consisting of,” will refer to the inclusion of exactly one element of a number or list of elements. In general, the term “or” as used herein shall only be interpreted as indicating exclusive alternatives (i.e., “one or the other but not both”) when preceded by terms of exclusivity, such as “either,” “one of,” “only one of,” or “exactly one of.” “Consisting essentially of,” when used in the claims, shall have its ordinary meaning as used in the field of patent law.

[0113] As used herein in the specification and in the claims, the phrase “at least one,” in reference to a list of one or more elements, should be understood to mean at least one element selected from any one or more of the elements in the list of elements, but not necessarily including at least one of each and every element specifically listed within the list of elements and not excluding any combinations of elements in the list of elements. This definition also allows that elements may optionally be present other than the elements specifically identified within the list of elements to which the phrase “at least one” refers, whether related or unrelated to those elements specifically identified. Thus, as a non-limiting example, “at least one of A and B” (or, equivalently, “at least one of A or B,” or, equivalently “at least one of A and / or B”) can refer, in one embodiment, to at least one, optionally including more than one, A, with no B present (and optionally including elements other than B); in another embodiment, to at least one, optionally including more than one, B, with no A present (and optionally including elements other than A); in yet another embodiment, to at least one, optionally including more than one, A, and at least one, optionally including more than one, B (and optionally including other elements); etc.

[0114] In the claims, as well as in the specification above, all transitional phrases such as “comprising,” “including,” “carrying,” “having,” “containing,” “involving,” “holding,” “composed of,” and the like are to be understood to be open-ended, i.e., to mean including but not limited to. Only the transitional phrases “consisting of’ and “consisting essentially of’ shall be closed or semi-closed transitional phrases, respectively, as set forth in the United States Patent Office Manual of Patent Examining Procedures, Section 2111.03.

Claims

CLAIMS1. A sensor for fluid contamination monitoring, the sensor comprising: a measurement medium disposed on an immersion cooling container and in physical contact with a reservoir of immersion cooling fluid contained within the immersion cooling container; a measurement signal source configured to emit a measurement signal at the measurement medium; a detector configured to receive at least a portion of the measurement signal reflected off of the measurement medium; and a processor, wherein: the processor is communicatively coupled to the detector and the measurement signal source; and the processor is configured to determine a contamination parameter of the immersion cooling fluid based on a comparison of the emitted measurement signal and the received measurement signal.

2. The sensor of claim 1, wherein the measurement signal source comprises at least one of a laser, a lightbulb, or a light-emitting diode (LED).

3. The sensor of claim 1, wherein the measurement signal source emits the measurement signal at a wavelength between about 100 nm to about 10 pm.

4. The sensor of claim 1, wherein a surface of the measurement medium in physical contact with the immersion cooling fluid comprises a textured surface, a roughened surface, or a coated surface.

5. The sensor of claim 1, wherein the measurement medium comprises a glass or a plastic.

6. The sensor of claim 1, wherein the detector comprises a charge-coupled device (CCD) sensor, a photodiode, a complementary metal-oxide semiconductor (CMOS) sensor, or an infrared sensor.

7. The sensor of claim 1, further comprising a heater disposed adjacent to the measurement medium.

8. The sensor of claim 1, wherein the processor is further configured to alter a physical property of an immersion cooling system based on the determined contamination parameter; wherein the physical property comprises at least one of a voltage, a current, a power, a temperature, a processing speed, a frequency, a temperature, a flow rate, a rotational speed, a memory state, a bandwidth, or a latency.

9. A method for fluid contamination monitoring, the method comprising: emitting, by a measurement signal source, a measurement signal at a measurement medium that is in physical contact with an immersion cooling fluid; receiving, by a detector, at least a portion of the measurement signal after being reflected from the measurement medium; comparing, by a processor, a characteristic of the emitted measurement signal to a characteristic of the received measurement signal; calculating, by the processor, a contamination parameter based on the step of comparing; and altering, by the processor, a physical property of an immersion cooling system in response to the contamination parameter.

10. The method of claim 9, wherein the physical property comprises at least one of a voltage, a current, a power, a temperature, a processing speed, a frequency, a temperature, a flow rate, a rotational speed, a memory state, a bandwidth, or a latency.

11. The method of claim 9, wherein the measurement signal source comprises at least one of a laser, a lightbulb, or a light-emitting diode (LED)12. The method of claim 9, wherein the measurement signal source emits the measurement signal at a wavelength between about 100 nm to about 10 pm.

13. The method of claim 9, wherein the detector comprises a charge-coupled device (CCD) sensor, a photodiode, a complementary metal-oxide semiconductor (CMOS) sensor, or an infrared sensor.

14. The method of claim 9, further comprising heating a portion of the immersion cooling fluid in physical contact with the measurement medium to or past a boiling point of the immersion cooling fluid.

15. A sensor for fluid contamination monitoring, the sensor comprising: a measurement medium disposed on a housing, the housing disposed within an immersion cooling container and in physical contact with a reservoir of immersion cooling fluid contained within the immersion cooling container; a measurement signal source configured to emit a first measurement signal at the measurement medium; wherein the measurement medium is configured to split a portion of the first measurement signal into a first split signal and a second split signal; a first detector disposed within the housing and configured to receive the first split signal; a second detector disposed externally to the housing and configured to receive the second split signal; and a processor, wherein: the processor is communicatively coupled to the first detector, the second detector, and the measurement signal source; and the processor is configured to determine a contamination parameter of the immersion cooling fluid based on a comparison of at least two of the first measurement signal, the first split signal, and the second split signal.

16. The sensor of claim 15, wherein the processor is further configured to alter a physical property of an immersion cooling system based on the contamination parameter.

17. The sensor of claim 16, wherein the physical property comprises at least one of a voltage, a current, a power, a temperature, a processing speed, a frequency, a temperature, a flow rate, a rotational speed, a memory state, a bandwidth, or a latency.

18. The sensor of claim 15, wherein the measurement signal source comprises at least one of a laser, a lightbulb, or a light-emitting diode (LED).

19. The sensor of claim 15, wherein the measurement signal source emits the measurement signal at a wavelength between about 100 nm to about 10 pm.

20. The sensor of claim 15, wherein a surface of the measurement medium in physical contact with the immersion cooling fluid comprises a textured surface, a roughened surface, or a coated surface.

21. The sensor of claim 15, wherein the measurement medium comprises a glass or a plastic.

22. The sensor of claim 15, wherein each of the first detector and the second detector comprises a charge-coupled device (CCD) sensor, a photodiode, a complementary metal-oxide semiconductor (CMOS) sensor, or an infrared sensor.

23. The sensor of claim 15, further comprising a heater disposed adjacent to the measurement medium.

24. A method for fluid contamination monitoring, the method comprising: emitting, by a measurement signal source, a first measurement signal; splitting, by a measurement medium in physical contact with an immersion cooling fluid, a portion of the first measurement signal into a first split signal and a second split signal; receiving, by a first detector disposed within a housing, the first split signal; receiving, by a second detector disposed outside the housing, the second split signal; comparing, by a processor, respective wavelengths or respective signal strengths of the first split signal and the second split signal; determining, by the processor, a contamination parameter of the immersion cooling fluid based on the compared respective wavelengths or respective signal strengths; and altering, by the processor, a physical property of an immersion cooling system in response to the contamination parameter.

25. The method of claim 24, wherein the physical property comprises at least one of a voltage, a current, a power, a temperature, a processing speed, a frequency, a temperature, a flow rate, a rotational speed, a memory state, a bandwidth, or a latency.

26. The method of claim 24, wherein the first measurement signal is emitted by a measurement signal source comprising at least one of a laser, a lightbulb, or a light-emitting diode (LED).

27. The method of claim 26, wherein the measurement signal source emits the first measurement signal at a wavelength between about 100 nm to about 10 gm.

28. The method of claim 24, wherein each of the first detector and the second detector comprises a charge-coupled device (CCD) sensor, a photodiode, a complementary metal-oxide semiconductor (CMOS) sensor, or an infrared sensor.

29. The method of claim 24, further comprising heating a portion of the immersion cooling fluid in physical contact with the measurement medium to or past a boiling point of the immersion cooling fluid.

30. A sensor for fluid quality management, the sensor comprising: a hot-wire anemometer disposed at least partially within an immersion cooling fluid; a Wheatstone bridge electrically coupled to the hot-wire anemometer and configured to be electrically altered based on at least one of a current or a resistance across the hot-wire anemometer; and a processor communicatively coupled to the Wheatstone bridge, the processor configured to calculate a heat transfer rate based on the current or the resistance.

31. The sensor of claim 30, wherein the processor is configured to calculate the heat transfer rate based at least in part on an inverse relationship between the current and one or more temperatures of the hot-wire anemometer.

32. The sensor of claim 31, wherein the processor is further configured to adjust an operational parameter of a component disposed at least partially within the immersion cooling fluid based on the heat transfer rate.

33. The sensor of claim 32, wherein the operational parameter comprises at least one of a frequency, a power, a voltage, or a rate.

34. The sensor of claim 30, wherein the immersion cooling fluid comprises at least one of a liquid phase, a froth phase, or a vapor phase.

35. A method for fluid quality management, the method comprising:measuring an electrical parameter of a sensor disposed at least partially within an immersion cooling fluid, the sensor comprising a hot-wire anemometer; determining a heat transfer rate associated with the immersion cooling fluid based at least in part on an inverse relationship between (A) and (B), where (A) is the electrical parameter of the sensor and (B) is an area of the sensor and a temperature difference between the sensor and the immersion cooling fluid; and controlling an operational parameter of a component disposed at least partially within the immersion cooling fluid based on the determined heat transfer rate.

36. The method of claim 35, wherein the operational parameter comprises at least one of a frequency, a voltage, or a rate.

37. The method of claim 35, wherein the immersion cooling fluid comprises at least one of a liquid phase, a froth phase, or a vapor phase.

38. The method of claim 35, wherein the electrical parameter comprises at least one of a current, a voltage, a resistance, a capacitance, or an impedance.

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