Tag Archives: cold plates

Tubed and Submerged-Fin Cold Plates in Electronics Thermal Management

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

Many of today’s electronic devices need the performance of liquid cooling to meet the thermal demands of certain hot components. Liquid cold plates are common cooling systems in high power lasers, fuel cells, battery coolers, motor drives, medical equipment, avionics and other high-power, high-heat flux applications.

Cold Plates
Figure 1. A Custom liquid cold plate design by D6 Industries. [1]

Cold plates provide localized cooling by transferring heat from a device to a liquid that flows to a remote heat exchanger and dissipates into either the ambient or to another liquid in a secondary cooling system. Component heat flows by conduction through a thermal interface material and the metal plate to the metal tubing. Then it flows by convection from the internal surface of the fluid path material into the flowing coolant.

A cold plate in electronics cooling is often an aluminum block with an embedded, coolant-filled metal tube. Another common cold plate type is made with metal shells that are brazed or friction-welded together and filled with a liquid coolant.  On the inside, the metal shells have integral cooling fins that are submerged in the coolant.

Tubed Cold Plates

Embedded tube designs are the simplest version of cold plate cooling devices. They feature a continuous tube set into grooves in a metal plate, and are often bonded in place with thermal epoxy. The flowing coolant moves heat from the component away from the cold plate to a heat exchanger, where it is cooled before being pumped back into the plate. 

A common example of a tubed cold plate features an aluminum plate with an exposed copper tube. The tubes can be routed in different pathways to optimize the thermal performance.

The tubing can be continuous or constructed from straight tubes connected by soldered joints, though joints may increase the potential for leakage.

Figure 2. A Tubed cold plate consists of copper or stainless-steel tubing pressed into a metal plate. [2]

This design can provide a cost-effective thermal solution for component cooling where the heat load is low-to-moderate. Tubed cold plates ensure minimum thermal resistance between the power device and the cold plate by placing the coolant tube in direct contact with the power device’s base. Direct contact reduces the number of thermal interfaces between device and fluid, thus increasing performance for the application.

A variant of this design features a thermal epoxy completely applied over the pressed in tubing and flush with the metal plate surface. These are sometimes called buried tube liquid cold plates. This provides a gap-free thermal interface between the tube and the plate. The epoxy layer protects from any leakage from the metal tube. Another key feature is that that fully buried tube is not exposed to the outside environment.

Figure 3. A buried tube cold plate’s metal tube is covered with a conductive epoxy layer. [3]

The choice of liquid coolant affects thermal performance as well. Choosing the right coolant depends to a great extent on the tube material. Copper tubes are compatible with water and most other common coolants, while stainless steel tubes can be used with deionized water or corrosive fluids.

One cold plate OEM offers a proprietary technology with a tube locking system and pressing techniques that ensure the tube is flush with the plate surface, providing good thermal contact with the component being cooled. This manufacturing method eliminates the need for thermal epoxy between the tube and plate which improves thermal performance. [4]

Submerged Fin Cold Plates

Another type of cold plate is an all-metal construction with brazed or friction welded internal fin field.

Figure 4. Standard, liquid coolant-containing metal cold plate [5]

The integral, internal fins increase the surface area that contacts the fluid and enhances heat transfer. Fin shape and fin density affect the performance of heat exchangers and cold plates. By their geometry, the fins also create turbulence, which minimizes the fluid boundary layer and further reduces thermal resistance.

One high-performance version features tightly packed aluminum pin fins that create turbulence with low flow rate values, resulting in high thermal performance with low pressure drop. In this design, the high density of the internal fins increases the heat transfer area without adding bulk to the cold plate assembly. [6]

Figure 5. Close-spaced pin fins with complex geometry create turbulence with low flow rate values inside submerged fin cold plates. [6]

In most high-performance applications, fins are made of copper or aluminum. Aluminum fins are preferred in aircraft electronic liquid cooling applications due to their lighter weight. Copper fins are mostly used in applications where weight is not an important factor, but compatibility with other cooling loop materials is.

For submerged-fin cold plates, many different fin geometries can be tested to find the best improvement in performance. Some of the most commonly used are louvered, lanced offset, straight, and wavy fins.

Figure 6. Fin designs for submerged-fin cold plates. Clockwise from top: louvered, lanced offset, wavy, and straight fins. [7]

With cooling requirements increasing in many areas of electronics, engineers are turning to liquid cooling to replace air cooling. Lower cost, safer liquid cooling systems have also spurred the trend to liquid cooling.

The prime example is the cold plate – relatively simple in design, affordable, available in alternative versions, and extremely customizable. Cold plates should be considered wherever thermal performance above air cooling is needed.

References:

  1. https://d6industries.com/portfolio/custom-designs-liquid-cold-plate-hydroblock/
  2. https://www.lytron.com/Cold-Plates
  3. http://www.wakefield-vette.com/products/liquid-cooling/liquid-cold-plates/standard-liquid-cold-plates.aspx
  4. https://www.lytron.com/Tools-and-Technical-Reference/Application-Notes/Assessing-the-Quality-of-a-Tubed-Cold-Plate
  5. https://www.qats.com/Products/Liquid-Cooling/Cold-Plates
  6. http://www.cooltech.it/products/liquid-cold-plates/
  7. https://www.lytron.com/Tools-and-Technical-Reference/Application-Notes/Fins-for-Cooling-Success

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. To register for Qpedia and to get access to its archives, visit https://www.qats.com/Qpedia-Thermal-eMagazine.


Join ATS for Live Liquid Cooling Webinar

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, Sept. 27 from 2-3 p.m. ET and will cover the design and deployment of liquid cold plates in electronics systems. Learn more and register at https://qats.com/Training/Webinars.

ATS Cold Plates Displayed at PCIM Europe in Richardson RFPD Booth

Thanks to its new distribution partnership with Richardson RFPD, Advanced Thermal Solutions, Inc. (ATS) was given the chance to display its new, high-performance cold plates at PCIM Europe 2018 held in Nuremberg, Germany at the beginning of June.

PCIM Europe 2018

ATS cold plates were displayed at the Richardson RFPD booth with Vincotech’s new mid-power VINcoPACK E3, which is a low-profile package for motion control and UPS applications that features a six-pack configuration. (Richardson RFPD)

The showcased solution demonstrated how a high-powered device easily connects with the mounting patterns manufactured on ATS cold plates to meet industry-standard insulated-gate bipolar transistors (IGBT), such as those from Mitsubishi, Vincotech, which was on display at PCIM (pictured above), and other leaders in the power electronics industry.

The flexibility in the ATS design allows for cooling of high-powered devices, such as those made from silicon carbide (SiC) or gallium nitride (GaN), without the need for associated tooling costs, which are commonly found when changing the mounting pattern of liquid cold plates.

The cold plates have an innovative, high aspect ratio fin field that provides 30% better thermal performance than comparable products on the market and are manufactured to be easily customizable for systems with specific thermal or space requirements.

ATS cold plates are the perfect choice for engineers looking for liquid cooling solutions for high-powered systems.

Richardson RFPD has a rich history of providing engineering solutions and distributing components for the global electronics market, with more than 35 locations around the world and specialized knowledge in power electronics. Richardson RFPD is the leader in helping customers design-in the latest products and most innovative technology from the market leaders on its line card.

PCIM Europe 2018, one of the largest power electronics shows on the continent, featured more than 11,000 visitors, more than 500 exhibition, and more than 800 conference attendees. Having ATS cold plates on display, thanks to the relationship with Richardson RFPD, gave ATS a host of potential new customers for its liquid cooling and power electronics cooling solutions.

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.

ATS Unveils Heat Exchanger Selection Tool

In 2017, Advanced Thermal Solutions, Inc. (ATS) added to its liquid cooling products with a new line of tube-to-fin, liquid-to-air heat exchangers with the industry’s highest density fins, which maximize heat transfer and provide greater cooling than other heat exchangers on the market.

Heat Exchanger Selection Tool

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

ATS heat exchangers are available in seven different sizes and can be ordered with or without fans depending on your specific design requirements. Altogether, ATS offers 49 different heat exchanger options (not including the customized options to meet customer needs).

To make the selection process easier for engineers, ATS has recently unveiled a new Heat Exchanger Selection Tool that will point engineers to the exact option that will meet the inputted criteria.

Heat Exchanger Selection Tool

The tool asks five questions (measurement type in parentheses):

  • Air temperature from inlet to heat exchanger (Tai°C)
  • Heat need to be extracted by heat exchanger (QtotalW)
  • Water exit temperature from heat exchanger (Tfo°C)
  • Water flow rate (GPM)
  • Fan voltage (V)

Plug answers in to these questions and hit the “Optimum Heat Exchanger” button to see which of the ATS heat exchangers fits your specific liquid cooling system needs. Once you have the right part number, you can now purchase the right heat exchanger from Digi-Key Electronics.

In addition to heat exchangers, ATS has an array of liquid cooling products, including cold plates that provide 30 percent better thermal performance than comparable products on the market.

To learn more about the full line of liquid cooling options from ATS, visit https://www.qats.com/Products/Liquid-Cooling.

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.

ATS Showcasing Thermal Solutions for Power Electronics at APEC 2018

Advanced Thermal Solutions, Inc. (ATS), a leading-edge thermal engineering and manufacturing company focused on the thermal management of electronics, is pleased to announce that it will be showcasing its new line of liquid cold plates and other thermal solutions for power electronics in Booth No. 1738 at APEC 2018, the world’s premier event for applied power electronics, being held in the Henry B. Gonzalez Convention Center in San Antonio, Texas from March 4-8.

APEC 2018

ATS will have a video demonstration and samples of its newly-released liquid cold plates, which boast an innovative, internal fin array with an optimized aspect ratio that provides 30 percent better performance than other commercially-available cold plates currently on the market.

ATS cold plates are the perfect thermal solution for power electronics, such as IGBT, wide-bandgap, and more.

“Even as power supplies and power ICs increase in efficiency, challenging thermal issues remain,” said Steve Nolan, ATS Vice-President of Sales and Business Development. “There is a demand for more power across the industry and ATS is committed to supporting the electronics industry with the right solutions in the varied component and end-markets on the market today, whether its cooling for IBGT, emerging wide-bandgap, power bricks, CPUs, BGAs or more.”

He added, “APEC provides us the opportunity to share our solutions with these manufacturers, as well as discuss how we can help with any of their future needs.”

ATS cold plates are the perfect solution for cooling high-powered electronics, such as IGBT modules. (Advanced Thermal Solutions, Inc.)

Cold plates are part of an array of liquid cooling solutions that ATS has to offer, including heat exchangers with the industry’s highest density fins to optimize heat transfer and a line of chillers for precise control of coolant temperature.

In addition to its liquid cooling solutions for power electronics, ATS will also showcase its popular Power Brick heat sinks, which are based on the patented maxiFLOW™ design and specially designed for cooling 1/8, 1/4, 1/2, and full-brick DC/DC power converters. ATS has added a straight-fin option to its line of power brick heat sinks to give power engineers an option with a smaller footprint for crowded boards.

ATS has straight-fin heat sinks as part of its Power Brick line to give additional cooling options for power engineers. (Advanced Thermal Solutions, Inc.)

ATS will also display samples of its vast array of high-performance flat and round heat pipes that are perfect for spreading heat away from high-powered components, particularly in boards that have high component-density and little space for other cooling methods.

Visit ATS at Booth No. 1738 at APEC 2018 and join Steve Nolan and Product Engineering Manager Greg Wong to learn more about the numerous thermal solutions that ATS has designed for the power electronics industry.

Find more information about ATS liquid cold plates, Power Brick heat sinks, or ATS consulting and design services, at https://www.qats.com/ or contact ats-hq@qats.com.