Tag Archives: liquid cooling

ATS Releases New Line of Tube-to-Fin, Liquid-to-Air Heat Exchangers

Advanced Thermal Solutions, Inc. (ATS) has introduced a new line of tube-to-fin, liquid-to-air heat exchangers that “push the boundaries of the technology with the industry’s highest density fins.” These new heat exchangers, available with or without fans, come in seven different sizes and 49 different options and are part of the array of liquid cooling products that ATS offers.

Heat Exchangers

ATS has released a new line of tube-to-fin, liquid-to-air heat exchangers that boast the industry’s highest density fins. (Advanced Thermal Solutions, Inc.)

ATS heat exchangers maximize heat transfer from fluid to air, which allows liquid to be cooled to lower temperatures than other heat exchangers on the market. The fins and tubes are made of copper and stainless steel and are suitable for a variety of different liquids, including water, dielectric fluids and custom designed heat transfer fluids.

Read the full product release announcement at https://www.qats.com/News-Room/Press-Releases-Content/1183.aspx.

ATS heat exchangers can be used in a variety of applications including laser cooling, cooling medical equipment and imaging devices, compressor cooling, semiconductor processing, HVAC, food and beverage processing, and other liquid cooling applications.

The following table shows the different heat transfer capacities and dimensions of the different heat exchangers that ATS has released:

Heat Exchangers

The heat exchangers have silver-solder brazed joints and have been internally cleaned and externally coated for corrosion protection. They are available with or without fans.

Watch the short video below to learn more:

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

How is a Heat Exchanger Used in Liquid Cooling

A heat exchanger is a device that transfers heat from a fluid (liquid or gas) to pass to a second fluid without the two fluids mixing or coming into direct contact. Heat exchangers are commonly used in liquid cooling systems to dissipate heat from a fluid that has passed over a cold plate attached to the heat-producing component. The cool fluid is pumped through the system and back across the cold plate.

Heat Exchanger

An example of a standard liquid cooling loop using a heat exchanger to transfer heat from the liquid to the ambient. (Advanced Thermal Solutions, Inc.)

Heat exchangers are designed to maximize the surface area of the wall between the two fluids, while minimizing the resistance to fluid flow through the exchanger. The addition of fins or corrugations in one or both directions increases the surface area and increases the heat transfer capacity of the heat exchanger.

There are several types of liquid-to-air heat exchangers.

In a shell and tube heat exchanger, one fluid flows through a series of metal tubes and the second fluid is pumped through a shell that surrounds them. The fluid flow can be either parallel (flowing in the same direction), counterflow (flowing in opposite directions) or crossflow (flows are perpendicular to each other).

Tube-to-fin heat exchangers (as shown in the GIF above) use fins surrounding two tubes that carry the fluids. The fins increase the surface area and maximize heat transfer to the ambient. Some finned tube heat exchangers use natural convection and other can include fans to increase the airflow and heat transfer capacity.

Plate and frame heat exchangers have two rectangular end members holding together a series of metal plates with holes in each corner to allow the liquids to pass through. Each of the plates has a gasket to seal the plates and arrange the flow of the fluids between the plates. Brazed plate heat exchangers avoid the potential for leakage by brazing the plates together. Plate and frame heat exchangers are commonly used in food processing.

Common applications for heat exchangers include telecommunications, process cooling, power electronics, medical device and medical imaging, automotive, industrial, and HVAC.

Watch the video below to learn more:

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

Industry Developments for Cooling Overclocked CPUs

By Norman Quesnel, Senior Member of Marketing Staff
Advanced Thermal Solutions, Inc.

(This article will be featured in an upcoming issue of Qpedia Thermal e-Magazine, an online publication dedicated to the thermal management of electronics. To get the current issue or to look through the archives, visit http://www.qats.com/Qpedia-Thermal-eMagazine. To read other stories from Norman Quesnel, visit https://www.qats.com/cms/?s=norman+quesnel.)

Almost as long as personal computers have been around, users have been making modifications “under the hood” to make them run faster. A large segment of these users are overclockers, who make adjustments to increase the clock speeds (the speed at which processors execute instructions) of their CPUs and GPUs.

Many PC gamers get into overclocking (OC) to make their programs run faster. Gamecrate.com, a gamer site, defines overclocking as the practice of forcing a specific piece of hardware to operate at a speed above and beyond the default manufactured rating. [1]

To overclock a CPU is to set its clock multiplier higher so that the processor speeds up. For example, overclocking an Intel Core i7 CPU means to push its rated clock speed higher than the 2.80 GHz that it runs at “out of the box.” When performed correctly, overclocking can safely boost a CPU’s performance by 20 percent or more. This will let other processes on a computer run faster, too.

Cooling Overclocked CPUs

Fig. 1. An Intel Core i5-469k Processor Can Be Overclocked to Run 0.5-0.9 GHz over Its Base Frequency. Air Cooling is Provided by a Hyper D92 from Cooler Master.[2]

To serve the global overclockers market, some chip makers keep the door open to overclocking by allowing access to their multipliers. They do this with a variety of “unlocked” processors. Intel provides many unlocked versions of their processors, as denoted with a ‘k’ at the end of their model number.

For example, the Skylake Core i7-6700k and Haswell-E Core i7-5820k are made with unlocked clock multipliers. In fact, Intel targets overclockers with marketing campaigns and support services.

Fig. 2. Intel Actively Targets Overclockers with Its Unlocked Processors.[3]

Besides gaming, overclocking can improve performance for applications such as 3-D imaging or high-end video editing. For GPUs, faster speeds will achieve higher frames per second for a smoother, faster video experience. Overclocking can even save money, if a lower cost processor can be overclocked to perform like a higher end CPU.[4]

For many gamers, overclocking enhances their enjoyment by giving more control over their system and breaking the rules set by CPU manufacturers. One overclocker on Gamecrate.com said, “Primarily, I like to do it because it’s fun. On a more practical note it’s a great way to breathe some life into an old build, or to take a new build and supercharge it to the next level.”[1]

Heat Issues from Overclocking

Overclocking a processor typically means increasing voltage as well. Thus, the performance boost from overclocking usually comes with added component heat that needs to be controlled. Basically, the more voltage added to components, the more heat they are going to produce. There are many tutorials on overclocking and most of these resources stress that it’s essential to manage a component’s increased heat.[5]

Programs are available that monitor the temperature of a processor before and after overclocking it. These programs work with the DTS, digital thermal sensors that most processor manufacturers include inside their component packages. One such program is Core Temp, which can be used with both Intel and AMD cores. Some component OEMs also offer their own software to monitor temperatures in their processors.[6]

Fig. 3. The Core Temp Program Can Display Temperatures of Individual Cores in a System.[6]

Typically, an overclocker will benchmark a CPU or other component to measure how hot it runs at 100 percent. Advanced users can manually do the overclocking by changing the CPU ratio, or multiplier, for all cores to the target number. The multiplier works with the core’s BCLK frequency (usually 100) to create the final GHz number.

Tools like the freeware program Prime95 provide stability testing features, like the “Torture Test,” to see how the sped up chip performs at a higher load. These programs work with the system’s BIOS and typically use the motherboard to automatically test a range of overclocked profiles, e.g. from 4.0-4.8 GHz. From here, an overclocker may test increasing voltages, e.g. incrementally adding 0.01 – 0.1 V while monitoring chip stability.

An overclocked component’s final test is whether it remains stable over time. This ongoing stability will mainly be influenced by its excess heat. For many overclocked processors, a robust fan-cooled heat sink in place of the stock fan is essential. For others, only liquid cooling will resolve excess heat issues.

Fan Cooling

The advantage of using air coolers is no worry about leaking, which may lead to component or system damage. With the air cooled heat sinks, the bigger and faster the fan (CFM), the better, and there are a multitude of fan-sink cooling solutions that gaming PCs can accommodate.

In reality, higher performance fan-cooled sinks typically also employ liquid. It is used inside heat pipes that more efficiently convey heat from the processor into the sink’s fan cooled fin field.

Fig. 4. The Top-Rated Hyper 212 EVO CPU Air Cooler from Cooler Master Has Four Heat Pipes Transferring Heat to Aluminum Fins.[7]

Air cooled heat sinks for overclockers cost well under $50 and are available from many sources. They’re often bundled with overclock-ready processors at discounted prices.

A greater issue with air cooling can be the fan noise. A high performance fan must spin very quickly to deal with heavy system workloads. This can create an unpleasant mixture of whirs, purrs and growls. Many of the gaming desktops generate 50-80 decibels of noise at load. Though most fans are quieter, pushing out 25-80 CFM, they are louder than most standard PC processor fans.[8]

Liquid Cooling

Liquid cooling has become more common because of its enhanced thermal performance, which allows higher levels of overclocking. Prices are definitely higher than air-cooled heat sinks, but liquid systems offer enthusiasts a more intricate, quieter, and elegant thermal solution with definite eye-appeal.

From the performance standpoint, liquids (mainly water in these systems) provide better thermal conductivity than air. They can move more thermal energy from a heat source on a volume-to-volume basis.

Fig. 5. The Top-Rated Nepton 280 Liquid CPU Cooler Has a Fast Pump Flow and a Large Radiator Cooled with Dual Fans that Reach 122 CFM Airflow.[9]

A typical liquid cooling system features a water block that fits over the overclocked CPU, a large surface area, a fan-cooled heat exchanger (radiator), a pump, and a series of tubes connecting all elements. One tube carries hot fluid out from the water block, the other returns it once it is cooled by the radiator. Some liquid cooling systems can also be used on multiple processors, e.g. a CPU and a gaming chipset.

While there are more components to a liquid cooling system, there are also major advantages. For one, the water block is usually much smaller and lower-profile than an attached, high-performance air cooler. Also, the tubing set up allows the heat exchanger and pump to be installed in different locations, including outside the PC enclosure. An example is the Sub-Zero Liquid Chilled System from Digital Storm. It unlocks overclocks of Intel’s i7-980X CPU up to 4.6 GHz while idling the processor below 0°C.[10]

Fig. 6. Digital Storm’s Cryo-TEC System Places an Overclocked CPU in Direct Contact with Thermo-electric Cold Plates Dropping Core Temperatures to Below 0°C.[11]

Prices for liquid cooling systems can easily surpass $200, though newer systems can be bought for under $100.

A fan still must be attached to the radiator to help cool it, but it doesn’t have to spin as quickly as it would if it were attached to a heat sink. As a result, most liquid-cooled systems emit no more than 30 decibels.

Conclusion

Overclocking can be considered a subset of modding. This is a casual expression for modifying hardware, software or anything else to get a device to perform beyond its original intention. If you own an unlocked CPU you can get significant added performance, for free, by overclocking the processor. When modifying processor speeds, i.e. increasing them, high temperatures will occur. Higher performance cooling solutions are needed.

Fig. 7. YouTube Video of Overclocked CPU Melting Solder Before It Stops Working at 234°C.[12]

To serve the world of overclockers, a steady stream of air and liquid cooling systems are being developed. Many of them are high precision, effective, stylish and surprisingly affordable. Often they share the same technology as mass market quantity, lower performing cooling systems (basic heat sinks, heat pipes, for example), but provide much higher cooling capabilities for ever-increasing processor speeds.

References
1. Gamecrate.com, https://www.gamecrate.com/basics-overclocking/10239
2. Techreport.com, http://techreport.com/review/27543/cooler-master-hyper-d92-cpu-cooler-reviewed/3
3. Legitreviews.com, http://www.legitreviews.com/intel-devils-canyon-coming-this-month-intel-core-i7-4790k-core-i5-4690k_143234
4. Digitaltrends.com, http://www.digitaltrends.com/computing/should-you-overclock-your-pcs-processor/
5. Techradar.com, http://www.techradar.com/how-to/computing/how-to-overclock-your-cpu-1306573
6. Alcpu.com, http://www.alcpu.com/CoreTemp/
7. Coolermaster.com, http://www.coolermaster.com/cooling/cpu-air-cooler/hyper-212-evo/
8. Digitaltrends.com, http://www.digitaltrends.com/computing/heres-why-you-should-liquid-cool-your-cpu/
9. Coolermaster.com, http://www.coolermaster.com/cooling/cpu-liquid-cooler/nepton-280l/
10. Gizmodo.com, http://gizmodo.com/5696553/digital-storms-new-gaming-pcs-use-sub-zero-liquid-cooling-system-for-insane-overclocks
11. Digitalstorm.com, http://www.digitalstorm.com/cryo-tec.asp
12. Youtube.com, https://www.youtube.com/watch?v=9NEn9DHmjk0

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

#JustChilling: ATS Recirculating and Immersion Chillers for Liquid Cooling Systems

ATS Chillers

Advanced Thermal Solutions, Inc. has a line of recirculating and immersion chillers for conditioning the coolant in liquid cooling systems. (Advanced Thermal Solutions, Inc.)


ATS offers a variety of chillers, including the CHILL V and CHILL iM series, for conditioning the coolant in liquid cooling systems. The ATS-CHILL V series, including the ATS-Chill150V, ATS-Chill300V, and ATS-Chill600V, are re-circulating, vapor compression chillers that offers precise coolant temperature control using a PID controller. The ATS-CHILL iM is an immersion chiller for precise control of the bath temperature by immersing the evaporator in a fluid bath.

Learn more about ATS recirculating and immersion chillers in this recent blog post or in the video below:

ATS Liquid Cooling Products

In addition to chillers, ATS has a complete product offering for Liquid Cooling Closed Loop Systems, including flow meters, leak detectors, heat exhangers, and cold plates. ATS can also design off-the-shelf or custom liquid cooling systems to meet the thermal needs of a project.

ATS 3-Core design approach identifies the type of cooling required at the analysis level and informs the client of its options, saving cost and time on design iteration and simulation verification. Once it is determined that liquid cooling is the option to pursue, the ATS design team identifies all the required components of the liquid loop, as well its packaging requirements and integration in the system.

ATS offers a complete array of off-the-shelf liquid loop components that can be readily deployed or custom-designed to meet the thermal requirements of the system. Subsequent integration of the liquid loop into the system provides the customer with a turn-key option for thermal management of their system.

Don’t get burned! Take advantage of ATS expertise in liquid and air cooling to ensure proper thermal management for your project.

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

Cold Plates and Recirculating Chillers for Liquid Cooling Systems

Recirculating Chillers

ATS cold plates and recirculating chillers can be used in closed loop liquid cooling systems for high-powered electronics. (Advanced Thermal Solutions, Inc.)


The miniaturization of high-powered electronics and the requisite component density that entails have led engineers to explore new cooling methods of increasing complexity. As a result, there is a growing trend in thermal management of electronics to explore more liquid cooling systems and the reintroduction, and re-imagining, of cold plate technology, which has a long history that includes its use on the Apollo 11 space shuttle.i

Thermal management of high-powered electronics is a critical component of a design process. Ensuring the proper cooling of a device optimizes its performance and extends MTBF. In order for a system to work properly, engineers need to establish its thermal parameters from the system down to the junction temperature of the hottest devices. The use of cold plates in closed loop liquid cooling systems has become a common and successful means to insure those temperatures are managed.

Cold plate technology has come a long way since the 1960s. At their most basic level, they are metal blocks (generally aluminum or copper) that have inlets and outlets and internal tubing to allow liquid coolant to flow through. Cold plates are placed on top of a component that requires cooling, absorbing and dissipating the heat from the component to the liquid that is then cycled through the system.

In recent years, there have been many developments in cold plate technology, including the use of microchannels to lower thermal resistanceii or the inclusion of nanofluids in the liquid cooling loop to improve its heat transfer capabilities.iii

An article from the October 2007 issue of Qpedia Thermal eMagazine detailed the basic components of a closed loop liquid cooling system, including:

• A cold plate or liquid block to absorb and transfer the heat from the source
• A pump to circulate the fluid in the system
• A heat exchanger to transfer heat from the liquid to the air
• A radiator fan to remove the heat in then liquid-to-air heat exchanger

The article continued, “Because of the large surface involved, coldplate applications at the board level have been straight forward…Design efforts for external coldplates to be used at the component level have greatly exceeded those for PCB level coldplates.”

Exploring liquid cooling loops at the board or the component level, according to the author, requires an examination of the heat load and junction temperature requirements and ensuring that air cooling will not suffice to meet those thermal needs.iv

To read the full article on “Closed Loop Liquid Cooling for High-Powered Electronics,” click http://coolingzone.com/blog/wp-content/uploads/2017/01/Qpedia_Oct07_Closed_Loop_liquid_cooling_
for_high_power_electronics.pdf
.

Chillers provide additional support for liquid cooling loops

In order to increase the effectiveness of the cold plate and of the liquid cooling loop, recirculating chillers can be added to condition the coolant before it heads back into the cold plate. The standard refrigeration cycle of recirculating chillers is displayed below in Fig. 1.

Chiller,s Cold Plates

Fig. 1. The standard refrigeration cycle for recirculating chillers. (Adavanced Thermal Solutions, Inc.)

Several companies have introduced recirculating chillers to the market in recent years, including ThermoFisher, PolyScience, Laird, Lytron, and Advanced Thermal Solutions, Inc. (ATS). Each of the chiller lines has similarities but also unique features that fit different applications.

In order to select the right chiller, Process-Cooling.com warns that it is important to avoid “sticker shock” because of testing conditions that are ideal rather than based on real-world applications. The site suggests a safety factor of as much as 25 percent on temperature ranges to account for environmental losses and to ensure adequate cooling capacity.v

The site also noted the importance of speaking with manufacturers about the cooling capacity that is needed, the required temperature range, the heat load of the application, the length and size of the pipe/tubing, and any elevation changes.

“Look for a chiller with an internal pump-pressure adjustment,” the article stated. “This feature enables the operator to dial down the external supply pressure to a level that is acceptable for the application. Because the remaining flow diverts internally into the chiller bath tank, no damage will result to the chiller pump or the external application.”

When trying to decide on the right size chiller for your particular application, there are several formulas that can help make the process easier. Bob Casto of Cold Shot Chillers, writing for CoolingBestPractices.com, gave one calculation for industrial operations. First, determine the change in temperature (ΔT), then the BTU/hour (Gallons per hour X 8.33 X ΔT), then calculate the tons of cooling ([BTU/hr]/12,000), and finally oversize by 20 percent (Tons X 1.20).vi

Not every application will require industrial capacity, so for smaller, more portable chillers, Julabo.com had a secondary calculation for required capacity (Q).

Q=[(rV cp)material+(rV cp)bath fluid]ΔT/t

In the above equation, r equals density, V equals volume, cp equals constant-pressure specific heat, ΔT equals the change in temperature, and t equals time. “Typically, a safety factor of 20-30% extra cooling capacity is specified for the chilling system,” the article continued. “This extra cooling capacity should be calculated for the lowest temperature required in the process or application.”vii

Comparison of Industry Standard Recirculating Chillers

Recirculating Chillers

Applications for liquid cooling systems with chillers

Recirculating chillers offer liquid cooling loops precise temperature control and coupled with cold plates can dissipate a large amount of heat from a component or system. This makes chillers (and liquid cooling loops in general) useful to a wide range of applications, including applications with demanding requirements for temperature range, reliability, and consistency.

Chillers have been part of liquid cooling systems for high-powered lasers for a number of years to ensure proper output wavelength and optimal power.viiiix To ensure optimal performance, it is important to consider safety features, such as the automatic shut-off on the ATS-Chill 150V that protects against over-pressure and compressor overload. Other laser-related applications include but are not limited to Deep draw presses, EDM, Grinding, Induction heating and ovens, Metallurgy, Polishing, Spindles, Thermal spray, and Welding.x

Machine hydraulics cooling and semiconductors also benefit from the inclusion of chillers in liquid cooling loops. Applications include CVD/PVD, Etch/Ashing, Wet Etch, Implant, Inductively Coupled Plasma and Atomic Absorption Spectrometry (ICP/AA), Lithography, Mass Spectroscopy (MS), Crystal Growing, Cutting/Dicing, Die Packaging and Die Testing, and Polishing/Grinding.xi

One of the most prominent applications for liquid cooling, heat exchangers, cold plates, and chillers is in medical equipment. As outlined in an ATS case study,xii medical diagnostic and laboratory equipment requires cyclic temperature demands and precise repeatability, as well as providing comfort for patients. For Harvard Medical School, ATS engineers needed to design a system that could maintain a temperature of -70°C for more than six hours. Using a cold plate with a liquid cooling loop that included a heat exchanger, the engineers were able to successfully meet the system requirements.

Liquid cooling with chillers are also being used for medical imaging equipment and biotechnology testing in order to provide accurate results. ATS CEO and President Dr. Kaveh Azar will discuss the “Thermal Management of Medical Electronics” in a free webinar on Jan. 26 at 2 p.m. For more information or to register for the webinar, click https://www.qats.com/Training/Webinars.

Conclusion

Closed loop liquid cooling systems are not new but are gaining in popularity as heat dissipation demands continue to rise. Using cold plate technology with recirculating chillers, such as the ATS-Chill150V, ATS-Chill300V, and the ATS-Chill600V, to condition the coolant in the system can offer enhanced heat transfer capability.

Portable and easy to use, ATS vapor compression chillers are air-cooled to eliminate costly water-cooling circuits and feature a front LED display panel that allows users to keep track of pressure drop between inlet and outlet and the coolant level. They each use a PID controller.

Recirculating Chillers

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

References
i http://history.nasa.gov/SP-287/ch1.htm
ii https://heatsinks.files.wordpress.com/2010/03/qpedia_0309_web.pdf#page=12
iii http://www.sciencedirect.com/science/article/pii/S0142727X99000673
iv https://www.qats.com/cpanel/UploadedPdf/Qpedia_Thermal_eMagazine_0610_V2_lorez1.pdf#page=16
v http://www.process-cooling.com/articles/87261-chillers-evaluation-and-analysis-keys-to-selecting-a-winning-chiller?v=preview
vi http://www.coolingbestpractices.com/industries/plastics-and-rubber/5-sizing-steps-chillers-plastic-process-cooling
vii http://www.julabo.com/us/blog/2016/sizing-a-cooling-system-control-temperature-process-heating-operations
viii http://www.laserfocusworld.com/articles/print/volume-37/issue-6/features/instruments-accessories/keeping-your-laser-cool0151selecting-a-chiller.html
ix https://www.electrooptics.com/feature/keeping-it-cool
x http://www.lytron.com/Industries/Laser-Cooling
xi http://www.lytron.com/Industries/Semiconductor-Cooling
xii https://www.qats.com/cms/2016/10/04/case-study-thermal-management-harvard-medical-school-tissue-analysis-instrumentation/