Author Archives: Norm Quesnel

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:

1. Increase external surface area with fins or a bonded heat sink
2. Improve internal conduction and reduce interface resistance
3. 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:

1. Balanced conduction and convection are critical
2. Targeted passive changes can yield significant gains
3. System-level optimization outperforms isolated fixes

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:

1. Analytical modeling identified areas requiring attention and possible solutions
2. Baseline CFD validated the findings in ‘1’ and identified thermal risks before failure
3. Heat sink upgrades alone are insufficient without airflow optimization
4. Iterative CFD enables targeted, low-risk refinement
5. 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:

1. Balanced conduction and convection are essential
2. Targeted passive improvements deliver measurable gains
3. 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