What is the ideal condition for thermal dissipation?

6 April, 2021

One question that we’ve seen coming up a lot on CFD and thermal management forums recently is what the ideal condition for thermal dissipation is.

In this blog, we’ll attempt to provide a (brief) answer to that question, along with some potentially helpful resources that thermal engineers may find useful when managing thermal dissipation.

So, first things first…

What is thermal dissipation?

Thermal dissipation is simply the process of heat transferring from one object to another colder object — or even just to its wider surroundings.

In electronics design, thermal dissipation is extremely important. A well-planned strategy for heat dissipation can help to ensure that components remain reliable and don’t risk overheating. This not only makes products that are better for end users, but can also save manufacturers millions of dollars on costly product recalls.

Is thermal dissipation the same as thermal distribution?

Both thermal dissipation and distribution management involve the adequate movement of heat to keep devices operating effectively. However, dissipation refers to the process of removing excess heat entirely, while distribution is simply about ensuring that heat doesn’t become concentrated within one, single ‘hot spot’.

Both are vital elements of thermal management and are often closely related — both being managed by the control of thermal resistance. 

What is the ideal condition for thermal dissipation?

The short answer is that there isn’t one. There is no one perfect set of conditions for thermal dissipation. It will all come down to the type of product you’re designing, the environment that product will operate in and the material that your device (or dissipation instrument) is made of. The right solution for a highly compact piece of power electronics may not be right for a lower power or more spacious device. Similarly, what works for an automotive solution may not be a viable option for a design set to be used in the aerospace industry.

While there is no one perfect set of conditions, there are some things that you can control when deciding how you want to dissipate heat.

Take for example the trusty heat sink. Heat sinks are by far the most common way to dissipate heat — typically being found in 90% of all electronics products. What a heat sink is made out of, however, is where designers can potentially improve the rate of thermal dissipation.

Material selection

The most common heat sink materials are aluminum alloys. These alloys are lightweight, mechanically soft and typically have good thermal conductivity, making them the perfect fit for most electronics products.

This said however, there are other options.

While copper is typically heavier, it has an even better thermal conductivity — roughly twice that of aluminum. Better still, diamond has an even higher thermal conductivity (five times that of copper) but inevitably comes with a higher price tag.

Texture and surface

The surface and texture of a heat sink can also impact dissipation. Surface defects, roughness, and gaps increase thermal contact resistance thereby reducing the effectiveness of a thermal solution. 

To address this, thermal interface materials such as thermal greases or pastes can be used to improve contact resistance and to minimize gaps on the heat sink’s surface.

Attachment method

Even how the heat sink is attached can have an impact on thermal dissipation. As such, the selection process should factor in both the thermal and the mechanical requirements of the thermal management solution, with common attachment methods including standoff spacers, flat spring clips, epoxy, and thermal tape.

Making the right choice through thermal simulation

Any considerations for thermal dissipation should be incorporated as early on in the design process as possible. Through the use of thermal simulation, engineers can test the thermal performance of devices before they are manufactured — swapping out different heat sinks, changing materials and experimenting with different designs.

By creating extremely granular models to examine heat dissipation, 6SigmaET makes it easy for engineers to understand the precise thermal challenges of their designs. A library of component models also allows them to experiment with different thermal solutions, creating the ideal conditions for dissipation within their own unique designs.

Want to learn more? Check out our latest research and thermal whitepaper reports.


Blog written by: Tom Gregory, Product Manager
 

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