By collecting and analyzing more relevant measurement data, electronic cooling systems can be designed for improved performance, reliability, and cost. It’s essential these measurements be as accurate as possible. Critical data points include component temperature, air temperature, air flow rate, and often air pressure. Accuracy becomes even more important when performing accelerated testing as seen in this post.
Research-grade instruments and specialized sensors, properly calibrated and operated, can measure chip temperatures and surrounding elements, such as local airflow. Separate instruments can be used to quantify specific conditions, but more real-use data is obtained when all points are collected simultaneously. Taken over a range of time and conditions, simultaneous measurements provide more accurate, actionable information. They also reduce the cost and set-up time for multiple studies.
Fig 1 – Input Ports for a Laboratory Instrument that Simultaneously Measures Air Velocity, Temperature and Pressure. [ATS]Fig 2 – High-quality Thermal Data Reduces Uncertainties in Cooling Solutions than Calculated Data. [ATS]
Accelerated Product Reliability Testing
Reliability testing at different temperatures and conditions is commonly performed to identify expected product life. When an electronic system is running, it continuously experiences temperature and power cycling. These fluctuations are typically normal, but should be factored into a comprehensive thermal profile study.
It’s not practical to wait years to see if a component fails. Accelerated life testing provides faster predictions. A commonly used predictive tool is the Arrhenius model shown below.
Accelerated life testing using the Arrhenius model is a method for predicting how long a product will last under normal conditions by running it at elevated temperatures for a shorter time. The temperature increase speeds up the same failure processes that would eventually occur in the field—compressing years of life into weeks of testing.
Accelerated life testing Arrhenius calculators can help estimate field lifetime, test duration, acceleration factors, activation energy, and field failure rates. These tools are useful when real-time qualification can’t be done. This is typical with electronic components and devices that need fast market introduction. One such calculator is found here: Accelerated Life Test Arrhenius Calculator. [1]
The Arrhenius Model handles pure thermal stress, while the Eyring Model includes temperature plus other active forces like humidity or voltage. [1,2]
Highly Accurate Thermal Instruments
Besides its design, a thermal instrument’s construction and calibration should be high quality, and not a source of more errors. Accurate, research-grade instruments are essential for valid engineering practices. Without them, reliability predictions for a new product are actually less reliable themselves.
Fig 3 – Candlestick Sensors are Thin Profile (0.5 mm) with a Small Base (9.5 mm dia) for Collecting Air Temperature and Velocity Data at Single or Multiple Locations. [ATS]Fig 4 – Here, Air Temperature and Velocity Measurements are Taken Every Second by an eATVS-8 Instrument. stageVIEW Software Provides a Wide Range of Data Collection Choices. [ATS]
Here are some of the ATS instruments available for temperature and velocity measurement and providing the highest-quality thermal reliability test results.
Conclusion
Temperature has a significant effect on reaction rate and the subsequent reliability prediction. Small errors in temperature and airflow measurements can significantly impact reliability predictions. Such errors typically occur in the measurement process or from using inaccurate instruments.
If thermal data is inaccurate, outcomes can include over-designed systems, cost overruns, and products not shipping.
Laboratory-quality thermal instruments can reduce or eliminate measurement and calculation mistakes, leading to higher quality, faster to market and ultimately lower cost products. Just as important, collected data needs to be correctly interpreted. Expert thermal engineers can do just that with data provided or that they obtain themselves.
More information on these topics can be seen at these ATS videos:
How to Properly Measure Air Velocity in Electronic Systems [Link] [3]
How to Perform and Understand Temperature Measurement within Electronic Systems [Link] [4]
Excess heat has affected electronic devices since their earliest days, becoming more critical with the advent of integrated circuits. Today, excess heat impacts the reliability, performance, and lifespan of devices and circuits across all applications. Common impacts of excess heat in electronics are:
Overheating: This can cause sudden shutdowns or failures. Elevated temperatures damage internal components, leading to permanent failure and potential safety risks—especially in high-power systems such as batteries and automotive electronics.
Lower performance: Overheating devices often throttle to reduce heat, and signal integrity may degrade, resulting in reduced performance. Maintaining operation within the designated temperature range lowers electrical resistance and power consumption while improving energy efficiency.
Shorter lifespans: High temperatures cause differential material expansion and deformation, damaging component structures and internal connections.
Thermal issues can also lead to field recalls and warranty claims. Dense PCB layouts may introduce thermal coupling between components, compounding heat-related risks.
Best practice is to engage thermal management specialists early. Effective thermal management controls and dissipates heat to maintain safe operating temperatures. Cooling solutions vary widely, but viable approaches exist for nearly every application.
Applying Professional Thermal Design
Effective cooling solutions require rigorous analysis at the concept stage, development, and testing. The thermal design process includes analytical modeling, experimental validation, and computational simulation across the full packaging domain—components, PCBs, shelves, chassis, and system enclosures.
Figure 1. CFD Simulation of Forced Airflow Across Areas of a Populated PCB.
Robust thermal design leverages both experimental and computational methods, using lab instrumentation and CFD tools such as FloTHERM, CFdesign, and Icepak, among other commercially available tools.
Empirical methods may include airflow or liquid testing, with measurements of velocity, temperature, and pressure, along with thermography using IR or liquid crystal techniques.
A disciplined, methodical approach consistently delivers strong results across diverse cooling challenges. OEMs can often avoid costly redesigns or recalls through expert thermal review, whether on-demand or via ongoing engineering partnerships. Subscription-based thermal services further accelerate validation and integrate thermal considerations earlier in development. More on these below.
Following are examples of carefully applied cooling design methodology.
Dual-Environment Thermal Analysis of a Sealed Offshore Electronics Enclosure
After detailed analytical modeling to envelop the solutions, CFD analysis was performed on a sealed offshore aquaculture enclosure operating in two passive environments: submerged seawater at 30°C and outdoor air at 40°C. The objective was to determine whether passive cooling could maintain component temperatures below 60°C.
Figure 2. (left) Outer Enclosure Temperature Contours. (center) An Internal Aluminum Sled to Transfer Component Heat to the Outer Enclosure. (right) Velocity Vectors Indicate the Slow Motion of the Internal Air.
The analysis showed the passive design was insufficient for the outdoor air case. Key limitations included weak natural convection and poor internal conduction to the enclosure walls. Hot spot spreading resistance significantly contributed to overall temperature rise.
Addressing the air case would also resolve the submerged case. Recommended improvements:
Increase external surface area with fins or a bonded heat sink
Improve internal conduction and reduce interface resistance
Integrate heat pipes or vapor chambers to reduce spreading resistance
Multi-Cold-Plate Liquid Cooling System Design and Optimization
An EV battery manufacturer developed a 4 kW liquid cooling system with four cold plates integrated into a loop including a heat exchanger, DC-DC converter, and onboard charger. The design required balancing thermal performance, manufacturability, and flow distribution.
Figure 3. Four Cold Plates Receive Chilled Coolant from a Heat Exchanger as Part of a Liquid Loop that Included a DC-DC Converter and On-board Charger.
ATS combined analytical modeling with CFD to optimize cold plate geometry and system flow. Key parameters included tube routing, thermal resistance, and pressure drop.
Figure 4. CFD Simulation of a Revised Cold Plate with 10 Tube Passes and 9 Tube Bends.
A 10-pass serpentine tube design maximized heat transfer while maintaining acceptable pressure drop and manufacturability. Additional improvements included optimized tube diameters and balanced manifold routing.
The study demonstrated that effective kilowatt-scale liquid cooling requires coordinated optimization of geometry, pressure drop, and flow distribution. General findings:
Balanced conduction and convection are critical
Targeted passive changes can yield significant gains
CFD-Driven Thermal De-Risking of a Ruggedized Rack System
A baseline-to-optimization CFD study was conducted on a sealed 241 W ruggedized rack system with a 55°C ambient limit. The goal was to identify thermal violations and develop a reliable cooling strategy.
Figure 5. CFD Baseline Model and Surface Temperature Contours of a Ruggedized Rack System.
Through iterative CFD-driven design changes, ATS improved airflow efficiency, heat sink performance, and heat routing. Final modifications included revised heat pipe routing, heat sink replacement, fan reconfiguration, and removal of airflow obstructions. All components achieved thermal compliance.
Figure 6. Surface Temperature Contours of the System’s (left) Original Pin-Fin Heat Sink, and Its Replacement (right) maxiFLOW Heat Sink.
The study showed that sealed systems require holistic optimization across airflow, heat flow routing, fan placement, and heat sink design. General findings:
Analytical modeling identified areas requiring attention and possible solutions
Baseline CFD validated the findings in ‘1’ and identified thermal risks before failure
Heat sink upgrades alone are insufficient without airflow optimization
Final designs improve both compliance and thermal margin
Thermal Optimization of a Passive Aluminum Enclosure
ATS evaluated a sealed passive aluminum enclosure dissipating 75.8 W at 25°C ambient. CFD and parametric analysis identified key thermal constraints and guided optimization.
Figure 7. (left) Distribution of Enclosure Components, (right) Enclosure Baseline Thermal Distribution CFD.
Using 3D CFD with conjugate heat transfer, ATS modeled conduction and natural convection. Results showed that achieving target performance required coordinated improvements across both mechanisms.
Enhancements included improved thermal interface materials, better heat spreading, optimized fin geometry, reduced obstructions, and added vent gaps to enhance natural convection pathways.
Figure 8. The Enclosure Thermal Optimization Included Adding Cross-Cut Venting Gaps to Optimize Natural Convection.
Passive cooling performance is governed by the interaction of internal conduction and external convection. Key limitations included interface resistance and restricted airflow, with diminishing returns from geometry-only changes. Findings:
System-level optimization is more effective than isolated changes
Conclusion
Modern electronics—including AI hardware—generate substantial heat loads, making thermal management a first-order design constraint. Large-scale systems such as data centers incorporate cooling from the outset, but thermal design is equally critical at smaller scales.
Figure 9. ATS Thermal Engineers Use Thermochromic Liquid Crystals to Reveal Hot Spots in Electronic Devices. See a Demonstration Video: https://www.youtube.com/watch?v=peewxRlNVqg
Every application presents unique challenges, and thousands of new devices each year require tailored cooling solutions.
When clients have excess heat issues, ATS engineers work closely with them to deliver cost-optimized, practical thermal and mechanical solutions that align with real-world schedules. The objective is consistent: deliver the right solution the first time.
For OEMs and others with continuing needs for thermal engineering, ATS now provides a subscription service. This comes with tiered support levels, ranging from periodic consultation to embedded engineering support within development teams. Contact ATS for more information on the thermal engineering subscription service.
Figure 10. ATS Thermal Engineering Consulting Tiers Match a Manufacturer’s Ongoing Needs.
To see more details on the above cooling applications, and others, see the Advanced Thermal Solutions, Inc. website, https://www.qats.com/Consulting
ATS has designed custom housing and chassis for a variety of products including
ATCA chassis with 4.5KW cooling capability,
Small enclosures such set-top boxes, network interface units, industrial and autonomous vehicle systems
High capacity 1U and 2U chassis with integrated air jet impingement to push the air-cooling capacity of the 1U chassis to over 1.8KW.
Integration of the cooling system, whether liquid or air, has enabled ATS clients to get their product out to the market right-the-first-time with superb thermal performance and right-cost.
In January, Advanced Thermal Solutions, Inc. (ATS) and engineering simulation software leader Future Facilities announced that ATS had purchased multiple seats of 6SigmaET, an electronics thermal simulation software, adding to its CFD (computational fluid dynamics) capabilities.
ATS engineers are now using 6SigmaET to perform CFD on electronics cooling applications to find optimized thermal solutions for customers. (Advanced Thermal Solutions, Inc.)
In a joint press release from the two companies, ATS founder and CEO Dr. Kaveh Azar said, “We have decades of experience with a broad base of commercially available CFD tools. For the electronics thermal management analyses, 6SigmaET showed excellent agreement with our empirical and analytical modelling.
He added, “We were equally impressed with its ease of use and a short learning curve. Our engineering team was able to apply the tool to different levels of simulation extending from component to system level modelling. The speed of convergence and ease of use of 6SigmaET, have made it the first CFD software to use.”
6SigmaET becomes the lead thermal simulation software for ATS engineers dealing with standard electronics cooling challenges. ATS engineers will be able to quickly and efficiently simulate junction and ambient temperatures across boards and components or define airflow to find fan operating points or get a better understanding of pressure drop in a system.
Dr. Azar continued, “We always want to be working with the best breed of tools to deliver the innovative, high-quality and cost-effective thermal management and packaging solutions our customers expect. As a result, this addition is good news for our customers. The rich features of the 6SigmaET thermal simulation package not only enable us to do more when it comes to simulation, but also allows us to further deliver the solution to our clients in a shorter time interval. It is my highest compliment to 6SigmaET development team for putting together such a robust and effective software.”
Adding 6SigmaET to ATS CFD capabilities, which also includes FloTHERM from Mentor and Autodesk CFD (formerly CFdesign), enables engineers to save customers time in the design phase and makes it easier for ATS engineers to devise optimal thermal solutions.
ATS engineer Anatoly Pikovsky said, “Visual is definitely a great thing to have. If you look at this temperature map, for instance, you can look at the defined map and say right away, okay I have a very high temperature right in the middle.”
Pikovsky, who was working on Autodesk CFD to design a customized cold plate for a customer, demonstrated how the software allows for him to analyze the pattern of fluid flow through complex geometries that were imported from SolidWorks drawings. He used the software to show hot spots and fluid velocity and how small changes, such as the number of fins within the cold plate, could alter the results.
Field Application Engineer Vineet Barot explained that he used 6SigmaET on a board in which there was pressure drop coming from vents at the end of the board. In simulations, he was able to add fins to the heat sink without altering the fan operating point and quickly provide a thermal solution that was presented to a customer. He said, “If you had a standard 1-U chassis you can build it from scratch and run it in half an hour.”
While CFD continues to evolve to handle more complex problems, while also becoming easier to use for engineers, simulations are only part of the solution.
ATS engineers also perform analytical modeling, literally putting pen to paper with basic thermodynamic equations, to define the problem and provide a reference point for simulations. Coupling analytical and computer modeling is what sets ATS apart from its competitors because it ensures that thermal solutions provided by CFD are correct.
“CFD will give you a solution, whether it’s right or wrong, it will give you a solution,” Pikovsky said. “That’s the way it’s designed. Analytical coupled with CFD gives you a good reference point to know whether you’re in the ballpark.”
Analytical modeling also speeds up the process of finding an optimized solution. Rather than spending days or weeks plugging in different fin numbers and heights or trying numerous heat sink geometries, ATS engineers can define a small range of iterations, limiting the variables for CFD, to avoid countless simulations, each of which could take hours to run.
Pikovsky said, “Maybe you’ve designed a heat sink for certain airflow and you want to determine the number of fins. You can do it with CFD, but you start varying fins and it’s going to take you days. Analytical is great because you can determine the optimal number of fins and start CFD with that.”
CFD is a critical component of ATS thermal consulting and design services. 6SigmaET has quickly been adopted by ATS engineers as the lead software and been used in the design of thermal solutions for a number of customers in the past few months.
But, it is the combination of CFD with ATS engineers’ emphasis on analytical modeling that has made ATS a leader in the thermal management of electronics.
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.
If you have any questions about Advanced Thermal Solutions, Inc. (ATS) liquid or air cooling products, next-generation thermal instruments, or expert thermal consulting and design services, contact ATS today by email at ats-hq@qats.com.
