Air vs Liquid Cooling: Advancements in Thermal Management for Power Electronics


Over the past few decades, Power & Energy have emerged as two of the fastest growing industries in electronics. Power conversion, inversion, and rectification as well as battery and fuel cell technologies have become integral to technological growth across all industries.

As power electronic systems become more complex and perform at higher power ranges, the form factors are getting smaller, making heat one of the greatest limiting factors to what can be accomplished. To handle the amount of power being dissipated, air cooling solutions must be optimized and enlarged to adequately remove the excess heat. In some cases, size becomes a limiting factor for forced convection solutions. In these cases where the size or weight of an air cooled system makes it impractical, liquid cooling is fast becoming the most popular alternative method.

Switching from an air-cooled system to liquid is not a decision to be made quickly or lightly; there are many factors and possibilities to consider when improving your thermal management to handle higher heat loads. Although market trends indicate that full liquid cooling systems will eventually be the industry standard for cooling power electronics, there are many options and hybrid solutions that can apply the benefits of both as your system evolves or upgrades. If budget or timeline constrictions are such that a direct switch to liquid is unrealistic, optimizing your forced convection solution either through design improvements or by introducing two-phase cooling or liquid components are viable interim solutions.

Engineers have been developing liquid systems that are complimentary to existingair cooled solutions that can be expanded to fully replace the air cooled systemsover time. This is done by focusing on the electronic devices that can gainimmediate benefit with liquid cooling. Utilizing fluid couplings, reliable pumpsystems, and compact heat exchangers, the system removes heat from the air flowto the liquid where it is transferred and managed elsewhere. In other cases,engineers are opting to fully replace their air cooled systems with liquid cooled toimmediately enable higher power outputs and optimize thermal performance.

As you consider the switch to liquid cooling in order to improve the performance of your power electronics devices andfacilities, there are several key determining factors:

  • What are your size, weight, and thermal performance requirements?
  • Can you further optimize your air cooled system?
  • How much longer will air cooled systems be a viable thermal solution for your application?
  • Are there any limitations on liquid or volume availability?
  • How long will it take for investment in liquid cooling to make a return on performance and efficiency?
  • How can liquid cooling be implemented or designed into your application? What will be the effect on application/facility down time?
  • How and when do you begin?

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