Category Archives: Vapor Chamber

Aluminum Vapor Chambers Create a Lightweight and Lower Cost Method for Thermal Management

Learn about how vapor chambers can be a key part of your thermal management solutions in this article. And learn about ATS’ off the shelf vapor chambers.

The ATS family of Aluminum vapor chambers are the largest and broadest set of off the shelf vapor chambers available today. From 25x25mm (1x1in) to 250x250mm (9.8×9.8in). Made in the USA, the vapor chambers are also available in Copper and Titanium.

The ATS family of Aluminum vapor chambers are the largest and broadest set of off the shelf vapor chambers available today. From 25x25mm (1x1in) to 250x250mm (9.8x9.8in).

==> See our entire line of Aluminum Vapor Chambers, off the shelf, at ATS’s web site: https://www.qats.com/Consulting/Heat-Pipe-and-Vapor-Chamber-Design

What are vapor chambers?

Vapor chambers, available in different metal types, use both boiling and condensation to maximize their heat transfer ability. They feature a solid metal enclosure with a wick structure lining the inside walls. The inside of the enclosure is saturated with a working fluid at reduced pressure. As heat is applied at one side of the vapor chamber, the fluid near the heat source reaches its boiling temperature and vaporizes. The vapor then travels to the other side of the vapor chamber and condenses into liquid. The condensed fluid returns to the hot side via the gravity or capillary action, ready to vaporize again and repeat the cycle. Heat sinks with embedded vapor chamber are lighter than solid metal heat sinks, which can make them more suitable for applications which are weight sensitive. you can learn about vapor chambers at the many articles on our blog at this link:https://www.qats.com/cms/category/vapor-chamber/


DOWNLOAD Our free engineering eBook “Vapor Chambers and Their Roles in Thermal Management of Electronics”

==> Our free engineering eBook “Vapor Chambers and Their Roles in Thermal Management of Electronics” can be downloaded here from ATS’ web site https://www.qats.com/cms/engineering-ebook-vapor-chambers/

Webinar: Heat Pipes & Vapor Chambers – How They Work and Their Deployment in Electronics Thermal Management, 10-22-20, 2PM EST

Heat pipes and vapor chambers are often lumped into liquid cooling, but, they are not actually cooling they are in fact moving heat from a hot location to another location where it is dissipated. And how they operate, how to choose them, and how to deploy them is a very important part of the thermal engineer’s toolbox. And we have a free webinar on this topic to help train you.

Heat Pipe Diagram showing Heat Flow

Our webinar “Heat Pipes & Vapor Chambers – How They Work and Their Deployment in Electronics Thermal Management” is being held at 2PM Eastern time on 10-22-20. In this webinar we’ll answer questions such as:

  • How do heat pipes and vapor chambers work?
  • Why heat pipes are not liquid cooling?
  • When is it best to use a heat pipe and when is it best to use a vapor chamber?

The webinar will be recorded, and for those who register, we will provide the recording for your review.

While the webinar lasts about an hour, we’ll have about 30-minutes for a Q&A afterward. Don’t delay, sign up today at the button below! NOTE: this webinar had been scheduled for 10/15 but due to scheduling conflicts, our team needed to move it to 10/22.

Have questions about heat pipes and vapor chambers? email us at ats-hq@qats.com and we’ll be happy to answer them and direct you to the right solution.

Thermal Performance of Heat Sinks with Heat Pipes or Vapor Chambers for Servers

Most blade servers for data and telecommunication systems use air to cool the high-power chips inside. As the power level of these chips keep increasing, the pressure is on thermal engineers to design ever higher performance air-cooled heat sinks. In recent years, advancements in manufacturing of thinner heat pipes and vapor chambers have enabled engineers to integrate the heat pipes and vapor chambers into the blade server heat sinks.

A heat pipe is a device with high thermal conductance that can transport large amounts of heat with a small temperature difference between its hot and cold ends. The idea of a heat pipe was first proposed by Gaugler [1]. However, only after its invention by Grover [2, 3] in the early 1960s, were the remarkable properties of heat pipes realized by scientists and engineers. It is now widely used to transport heat from one location to another location or to smooth the temperature distribution on a solid surface.

A heat pipe is a self-driven two-phase heat transfer device. A schematic view of a heat pipe is shown in Figure 1. At the hot section (evaporator), the liquid evaporates and turns to vapor. The vapor flows to the cold section (condenser) and liquefies there. The liquid is driven back from the cold section to the hot section by a capillary force induced by the wick structure. By using boiling and condensation, the heat pipes can transfer and spread the heat from one side to another side with a minimum temperature gradient.

Figure 1. Typical heat pipe. [4]

Vapor chambers are flat heat pipes with very high thermal conductance. They have flat surfaces on the top and bottom sides.  See Figure 2, which can be easily attached to a heat source and a heat sink.

Figure 2. Vapor chamber. [5]

Just like heat pipes, vapor chambers use both boiling and condensation to maximize their heat transfer ability. A vapor chamber generally has a solid metal enclosure with a wick structure lining the inside walls. The inside of the enclosure is saturated with a working fluid at reduced pressure. As heat is applied at one side of the vapor chamber, the fluid at locations close to the heat source reaches its boiling temperature and vaporizes. The vapor then travels to the other side of the vapor chamber and condenses into liquid. The condensed fluid returns to the hot side via the gravity or capillary action, ready to vaporize again and repeat the cycle.

In electronics cooling, heat pipes are generally used to move the heat from electronics to heat dissipation devices. For example, in a desktop computer, multiple heat pipes are used to transfer heat from a CPU to an array of cooling fins, which dissipate the heat to ambient environment through convection. Vapor chambers are generally used to spread heat from a small size device to a larger size heat sink, as it is shown in Figure 2. If used in server heat sinks, the heat pipes and vapor chambers are both used to spreading the heat due to the low profile and large footprint of the heat sinks.

Compared to copper heat spreaders, heat pipes and vapor chambers have the following merits.

First, they have a much higher effective thermal conductivity. The pure copper has a thermal conductivity of 401 W/m°C and the best conductive material of diamond has a thermal conductivity of 1000-2000 W/m°C. The effective thermal conductivity of a well-designed heat pipe and vapor chamber can exceed 5000 W/m°C, which is an order of magnitude higher than that of pure copper. Second, the density of the heat pipe and vapor chamber is much lower than that of copper. Due to its hollow structure, the heat spreaders made by vapor chambers are much lighter than those made of copper. These properties make them the ideal candidate for high heat flux and weight sensitive heat spreading applications.

Dynatron Corporation is an electronic cooling provider specializing in heat sink for servers. This article compares the thermal performance of its server heat sinks, some of which have integrated vapor chambers. Figure 3 shows the photos of two Dynatron 1U passive server heat sinks for Intel’s Sandy Bridge EP/EX Processors. The R12 is made of pure copper with skived fins. The R19 has a vapor chamber base and stacked copper fins. The heat sink specification is listed in Table 1. The R19 is 150g lighter than the R12.

Figure 3. Dynatron passive heat sinks R12 (left) and R19 (right). [6]
Table 1. Dynatron passive heat sink specification.

Figures 4 and 5 show the thermal performance of R12 and R19 at different flow rates. At 10CFM, both heat sinks have a thermal resistance of 0.298ºC/W. When the flow rate increases to 20CFM, the R19’s thermal resistance is 0.218ºC/W, which is 0.020ºC/W lower than that of R12.

Figure 4. Dynatron R12 heat sink performance. [6]
Figure 5. Dynatron R19 heat sink performance. [6]

Figure 6 shows the photos of two Dynatron 1U active server heat sinks for Intel’s Sandy Bridge EP/EX Processors. The R18 is made of copper with skived fins. The R16 has vapor chamber base and stacked copper fins. Both heat sinks use same blower. The heat sink specification is listed in Table 2. The R16 is 90g lighter than the R18.

Figure 6. Dynatron active heat sinks R18 (left) and R16 (right). [6]
Table 2. Dynatron active heat sink specification. [6]

Figures 7 and 8 show the thermal performance of R18 and R16 at different blower speeds. At 3000RPM, the R18 and R16 heat sinks have thermal resistance of 0.437ºC/W and 0.393ºC/W, respectively. When the blower speed increases to 6000RPM, the R18’s thermal resistance is 0.268ºC/W and the R16’s thermal resistance is 0.241ºC/W. The R16 is constantly able to outperform the R18 at different blower speeds and its thermal resistance is 10% lower than R18.

Figure 7. Dynatron R18 heat sink performance. [6]
Figure 8. Dynatron R16 heat sink performance. [6]

The comparison of the Dynatron heat sinks shows that heat sinks with vapor chambers have a slight thermal edge vis-a-vis its copper counterparts even though they are light. This is true for both passive and active heat sinks.

Glover et al., for Cisco, have tested different heat sinks either with embedded heat pipes or vapor chambers for their servers and published their findings [7]. They tested five different heat sinks from different vendors, who utilized different manufacturing technologies to fabricate the heat sinks. The five heat sinks are similar in size: 152.4 x 101.6 x 12.7mm. Table 3 summarizes the physical attributes of these five heat sinks.

Table 3. Cisco tested heat sink specification. [7]

Figure 9-11 shows the three vapor chamber heat sinks with different vapor chamber structures and fin designs. Heat sink A-1 is an extruded aluminum heat sink with a vapor chamber strip. The 40 mm wide vapor chamber strip is embedded in the center of the base. It is the lightest one among five tested heat sink. Heat sink B-1 and C-1 have full base size vapor chamber and aluminum zipper fins.

Figure 9. Heat sink with vapor chamber A-1. [7]
Figure 10. Heat sink with vapor chamber B-1. [7]
Figure 11. Heat sink with vapor chamber C-1. [7]

Figures 12-13 show the two heat sinks with embedded heat pipes. Heat sink C-2 has heat pipes embedded inside its aluminum base. It uses zipper fins and has a copper slug in the middle of the base. Heat sink D-1 has three flat heat pipes embedded in its base. It has a copper plate as base.

Figure 12. Heat sink with heat pipes C-2. [7]
Figure 13. Heat sink with heat pipes D-1. [7]

Glover et al. tested the five heat sinks at different mounting orientation and air velocity. Table 4 presents the summary results of the heat sinks at 3m/s approach air velocity. The tested heat sinks were mounted horizontally with heater sources underneath the heat sink bases.

Table 4. Heat Sink Performance at 3 m/s with horizontal mounting position and bottom heating. [7]

The C-1 heat sink has the lowest thermal resistance; thus, its values are used as the benchmark for other heat sinks. The performance of heat sinks is purely design dependent. For vapor chamber heat sinks, the thermal resistance value varies from 0.19 to 0.23°C/W for 30 W of power. For heat sinks with heat pipes, the C-2 heat sink has a thermal resistance of 0.23°C/W, which matched with that of A-1 and B-1.

The D-1 heat sink has the highest thermal resistance, which is the result of inferior design and manufacture. However, the D-1 heat sink still has relatively low thermal resistance when it is compared to a regular heat sink without a heat pipe and vapor chamber.

Figure 14 shows the thermal resistance of the five heat sinks for 60W of input power at different air velocities. The C-1 heat sink performs best for all velocities and the D-1 heat sink’s performance is the worst.

Figure 14. Heat sink thermal resistance at 60 W. [7]

The pressure drop across the heat sink at different air velocities was also measured and the results were plotted in Figure 15. The B-1, C-1 and C-2 heat sinks have similar fin structures. Therefore, their pressure drop is similar, too. The pressure drop of the A-1 and D-1 heat sinks are similar and higher than the other heat sinks. This is because the A-1 heat sink has thicker fins and the D-1 heat sink has a thicker base.

Figure 15. Heat sink pressure drop. [6]

Because the heat pipes and vapor chambers use capillary force to drive liquid back from the condensation section to the evaporation section, their thermal performance is prone to orientation variation. Glover et al. also investigated the effects of the mounting orientation on the performance of the five heat sinks. They found the effect of the orientation is design dependent and is the result of both the wick structure and the entire heat sink assembly construct.

The heat sink specification from Dynatron Corporation and the test results from Cisco, show that the server heat sinks with embedded heat pipes or vapor chamber have a better thermal performance than their copper counterparts. The heat sinks with embedded heat pipes or vapor chamber are also lighter than the pure copper heat sinks, which make them more suitable for applications which are weight sensitive. If the cost of such heat sinks is justified, they are definitely good candidates for server cooling applications.

References

  1. Gaugler, R. S., US Patent 2350348, Appl. 21 Dec, 1942. Published 6 Jun. 1944.
  2. Grover, G. m., US Patent 3229759. Filed 1963.
  3. Grover, G. M., Cotter, T. P., and Erickson, G. F., “Structure of Very High Thermal Conductance.” J. App. Phys., Vol. 35, P. 1990, 1964.
  4. http://www.lightstreamphotonics.com/technology.htm
  5. http://www.thermacore.co.uk/vapour-chamber
  6. http://http://www.dynatron-corp.com
  7. Glover, G., Chen, Y., Luo, A., and Chu, H., “Thin Vapor Chamber Heat Sink and Embedded Heat Pipe Heat Sink Performance Evaluations,” 25th IEEE SEMI-THERM Symposium, San Jose, CA, USA, 2009.

For more information about Advanced Thermal Solutions, Inc. (ATS) thermal management consulting and design services, visit https://www.qats.com/consulting or contact ATS at 781.769.2800 or ats-hq@qats.com.

Webinar on Heat Pipes and Vapor Chambers

Advanced Thermal Solutions, Inc. (ATS) is hosting a series of monthly, online webinars covering different aspects of the thermal management of electronics. This month’s webinar will be held on Thursday, Nov. 29 from 2-3 p.m. ET and will cover the role of heat pipes and vapor chambers in heat transfer. Learn more and register at https://qats.com/Training/Webinars.

Applications of Vapor Chambers in Thermal Management of Electronics

The use of vapor chambers in the thermal management of electronics has grown exponentially since Advanced Thermal Solutions, Inc. (ATS) first wrote seven years ago about their ability to spread heat uniformly across the base of a heat sink, reducing the spreading resistance and enhancing the heat sink’s heat transfer capabilities when applied to high-powered components.

In a two-part series published originally in 2010 and based on an article from Qpedia Thermal eMagazine entitled, “Vapor Chambers and Their Use in Thermal Management,” it was explained that “a vapor chamber (VC) is basically a flat heat pipe that can be part of the base of a heat sink. It is vacuumed and then injected with just enough liquid (e.g. water) to wet the wick.” [1]

Similar to heat pipes, “The heat source causes the liquid to vaporize on the evaporator side. The resulting pressure increase in this area forces the vapor into the condenser side, which is the base of the heat sink. Here, the vapor transfers the heat to the heat sink, and it then condenses back to liquid. The liquid is pumped back to the base through the capillary action of the wick structure.”

In Fig. 1, two heat sinks are shown. One has a solid base and the other has a vapor chamber in its base and it is clear from the temperature distribution that the vapor chamber spreads out the heat across the base and distributes heat to a larger portion of the heat sink.

As the original article explained, “The very high equivalent thermal conductivity of the vapor chamber has spread the heat uniformly, leading to more efficiency from the heat sink.”

Vapor Chambers

Figure 1. Schematic View of Heat Sinks with (a) Solid Base and (b) Vapor Chamber Base. [1]

The second article runs through some of the equations that define the effective thermal conductivity of the wicking structure inside the vapor chamber and the impact that changing the wick material can have on its efficiency.

“This article shows that while a vapor chamber presents exciting technology, some calculations should be made to justify its use,” it continued. “In some situations, a solid copper block might provide better thermal performance than a vapor chamber. To use a vapor chamber instead of solid copper must be justified, for example, to reduce weight.

Another issue with vapor chambers presented by the article was that “some vapor chambers have a power limit of 500 watts. Exceeding this value might cause a dry out, as with a heat pipe, and could increase the vapor temperature and the pressure. The increase in internal pressure can deform the VC surfaces, or cause leakage from the welded joints.”

The study of vapor chambers has developed in the past seven years and, although some of the same issues remain, they are now thinner and lighter than ever and engineers are finding many new ways of incorporating them into cooling systems. Vapor chambers are now frequently used in applications ranging from hard drive disk cooling, PC cooling (not just for gamers and overclockers, but also for office computers), graphic card cooling, server cooling, high heat flux chips (IGBT and MOSFET), LED, and in consumer products (particularly mobile devices such as cell phones and tablets).

In addition to the benefits explained above, vapor chambers are critical in applications where height is limited, which is an increasing problem in today’s era of miniaturization, and where power densities are high. Vapor chambers are also important in applications where there are hotspots, where weight is a concern, and where there is a high ambient temperature or low airflow.

Hard Drive Disk Cooling

Several manufacturers in the hard drive market have turned to vapor chambers because of increases in spindle speed. In the past, many manufacturers and designers limited the thermal management of hard drives to using the aluminum case as a heat sink to dissipate the excess heat from the device, but as drives began working at 7,200 RPM and higher another option was required to ensure the reliability and longevity of the drive. [2]

A 2013 study that was published in International Communications in Heat and Mass Transfer explored the use of vapor chambers to cool hard drives in personal computers. The researchers found that adding vapor chambers to the cooling system could reduce the hard drive temperature by as much as 15.21%. [3]

Gaming, Overclocking, Personal Computing

The gaming and overclocking community has turned towards liquid cooling in recent years, as evidenced by a recent survey from KitGuru that showed 51% of its readers had already or would shortly be using liquid cooling for their personal computers. [4] While there is a trend in that direction, just under half (49%) of the respondents were also sticking with convection cooling options and many companies are incorporating vapor chamber technology in elaborate cooling devices (many with fans and heat pipes) for the PC market.

Cooler Master has introduced the V8 GTS CPU Air Cooler, which strongly resembles a car engine and has a horizontal vapor chamber and eight heat pipes. [5] The vapor chamber spreads the heat evenly from hotspots in the CPU and the heat pipes draw that heat into the tower’s heat sink.

Vapor Chambers

The Cooler Master GTS V8 has a distinct car engine look and uses vapor chambers, heat pipes, and heat sinks to cool PCs. (Cooler Master/YouTube)

ID Cooling has introduced several products that boast vapor chamber technology, including the HUNTER, and FI (which stands for Finland) Series CPU coolers. [6] Even gaming systems have gotten into the act with the recently announced, high-powered Xbox One Scorpio expected to include a vapor chamber array as part of its thermal management. [7] Microsoft’s announcement that it was using vapor chambers in Project Scorpio was not surprising because of the technology’s ability to fit into the tight confines of the gaming system.

Microsoft’s Project Scorpio introduced a new, higher-powered gaming system that required an array of vapor chambers to keep it cool. (Microsoft)

Also, the increasing capabilities and power of next-generation graphics cards has led to a trend in the industry to use vapor chambers as part of a package to cool these components. Nvidia is one of the biggest names in graphic cards and for both the Titan X and the GeForce GTX 1080 (each launched in 2016) vapor chamber are used with a blower to dissipate the increased power of the devices. [8]

It is not only the gaming community that is benefiting from vapor chamber cooling. Hewlett Packard (HP) has also explored using vapor chambers for multiple purposes. HP released a white paper last year about using 3-D vapor chambers in its Z Coolers to enhance their thermal efficiency as well as reduce the acoustic impact of the fans. [9] Also last year, HPE Labs released a study of vapor chambers for cooling multiple chip modules dissipating 250 W and operating temperatures up to 45°C and found that “VC (vapor chamber) performs better for: high power, power density, off center or asymmetric heat sources.” [10]

Server Cooling

Much like in graphic cards or gaming systems, vapor chambers are increasingly used in server cooling applications because their size and weight allows them to fit into tight spaces, particularly in applications with high component density. For example, Rugged has released an M120 1-U server rack that includes vapor chambers to spread the heat evenly and high-speed fans to pull the heat out of the system. [11]

A study by Aavid Thermacore from the 2007 ASME InterPACK Conference explained that in blade processors that need to dissipate 100-300 W with heat sinks lower than 30 mm, vapor chambers could be used as the base of the heat sink to improve effective spreading and improve performance by 25-30%. [12] Radian’s Intel Skylake heat sink that is intended for server chips installed in a 1-U chassis put this into practice with a vapor chamber in its base that enhances the effective thermal conductivity of the stamped aluminum fins. [13]

Radian’s Intel Skylake heat sink uses a vapor chamber in the base to evenly spread the heat and improve the heat transfer through the fins of the heat sink. (Radian)

For more on the topic of vapor chambers as heat sink bases, read https://www.qats.com/cms/2017/07/26/vapor-chambers-solid-material-base-high-power-devices.

LED Cooling

A more recent development in the use of vapor chambers is their inclusion in LED packages. A 2016 study from the 37th International Electronic Manufacturing Technology Conference outlined the use of vapor chambers along with finned heat sinks in the thermal management of LED to enhance the thermal performance and provide a “more economical” process than making the heat sink larger or using more expensive materials. [14]

Advanced Cooling Technologies (ACT) also released a case study about cooling high-powered LED applications, such as ultraviolet (UV) cutting devices, which said, “Vapor Chambers are an important tool in LED thermal management, since they act as flux transformers, spreading the high input heat flux over the entire surface of the vapor chamber. This allows the heat to be removed from the vapor chamber by conventional cooling methods.” [15] ACT added that it developed C.T.E matched vapor chambers that allow for direct bonding with the LED and “dissipate heat fluxes as high as 700 W/cm2 and 2kW overall.”

Vapor chambers are also being used in automotive LED applications to prevent failures by spreading the heat quickly from the source. A study from the 2011 International Heat Pipe Symposium found that a vapor chamber with distilled water dropped the LED temperature from 112.7°C to 80.7°C, reduced thermal resistance by 56%, and reached steady state faster than conventional systems. [16]

Mobile Devices

The most obvious market for vapor chambers is mobile devices. Last fall, the news was filled with stories about Samsung cell phone batteries reaching thermal runaway and airplane passengers being forced to turn off the phones for concern about a midair fire. With their thin design and low weight, vapor chambers can be used to spread the heat quickly from batteries or high-powered processors in phones, laptops, tablets, etc. and reduce the risk for catastrophic failures.

A 2016 study from the International Journal of Heat and Mass Transfer described vapor chambers being used to reduce hotspots to improve the comfort of users, which is a problem unique to mobile devices. [17] The researchers proposed a “biporous condenser-side wick design” that “facilitates a thicker vapor core, and thereby reduces the condenser surface peak-to-mean temperature difference by 37% relative to a monolithic wick structure.”

A recent story from EE Times noted that the combined shipments of mobile devices was expected to decline in 2017, marking the third straight year of reduced shipments [18], but with companies expending resources to develop 5G technology there is still a need for superior cooling options moving forward and vapor chambers appear to be a perfect fit in mobile thermal management systems.

References
[1] “Vapor Chambers in Thermal Management”, Qpedia Thermal eMagazine, Sept. 2007.
[2] http://www.pcguide.com/ref/hdd/op/packCooling-c.html
[3] P. Naphon. S. Wongwises, and S. Wiriyasart, “Application of two-phase vapor chamber technique for hard disk drive cooling of PCs,” International Communications in Heat and Mass Transfer, January 2013.
[4] https://www.kitguru.net/components/cooling/andrzej/majority-of-kitguru-readers-now-planning-on-liquid-cooling/
[5] http://www.coolermaster.com/cooling/cpu-air-cooler/v8-gts/
[6] http://www.idcooling.com/Product/series/category_parent/25/name/AIR%20COOLING
[7] https://www.youtube.com/watch?v=RE2hNrq1Zxs
[8] http://www.pcworld.com/article/3102027/components-graphics/nvidias-monstrous-new-titan-x-graphics-card-stomps-onto-the-scene-powered-by-pascal.html and https://www.nvidia.com/en-us/geforce/products/10series/geforce-gtx-1080/
[9] http://www8.hp.com/h20195/v2/getpdf.aspx/4AA6-1205ENW.pdf?ver=2.0
[10] https://www.labs.hpe.com/techreports/2016/HPE-2016-85.pdf
[11] http://www.coresystemsusa.com/filedata/prod/443m120_1u_rugged_rackmount_computer.pdf
[12] http://proceedings.asmedigitalcollection.asme.org/proceeding.aspx?articleid=1595384
[13] https://www.radianheatsinks.com/intel-skylake-heatsink/
[14] K.S. Ong, C.F. Tan, K.C. Lai, K.H. Tan, and R. Singh, “Thermal management of LED with vapor chamber and thermoelectric cooling,” 37th International Electronic Manufacturing Technology Conference, 2016.
[15] https://www.1-act.com/led-thermal-management-case-study-cte-matched-vapor-chamber/
[16] Ji Won Yeo, Hyun Jik Lee, Soo Jung Ha, et al., “Development of Cooling System of LED Headlamp for Vehicle Using Vapor Chamber Type Heat Pipe,” 10th International Heat Pipe Symposium, November 2011.
[17] GauravPatankar, Justin A.Weibel, and Suresh V.Garimella, “Patterning the condenser-side wick in ultra-thin vapor chamber heat spreaders to improve skin temperature uniformity of mobile devices,” International Journal of Heat and Mass Transfer, October 2016.

For more information about Advanced Thermal Solutions, Inc. (ATS) thermal management consulting and design services, visit www.qats.com or contact ATS at 781.769.2800 or ats-hq@qats.com.