Category Archives: heat sink

We wrote a three part series, “How to Apply Natural Convection Cooling for the Thermal Management of Electronics” during the week of August 22nd. Many of you liked our technical post so we thought we’d follow that up with a little focus on fin spacing.

Fin spacing is also known as channel spacing, the channel being the width from one fin to the next in a heat sink as illustrated in this drawing:

Here we see that the “B” dimension is the channel width or the fin spacing of this heat sink.

So what’s the big deal on fin spacing? Well, as usual in thermal engineering quite a bit more than meets the eye. The fin spacing of a heat sink, if not optimized for your application, can actually  reduce the thermal efficiency of your heat sink. If the fins are too narrowly place then the channel is too narrow and air has a harder time getting through!  Think of air as it really is: a fluid. Don’t forget that in physics, a fluid can be either liquid or a gas. That should help you to visualize what’s going on.  One case in particular was very interesting

The project we were working on was  for a rather large heat sink, (about the size of a hardcover dictionary if anyone remembers those!) for a wireless network remote radio head (RRH) application. The customer was another Tier 1 Telecommunications Equipment OEM. The customer actually had developed their own heat sink for natural convection cooling. It’s specifications were:

35 Fins

5mm base

Thermal Resistance of 1.39 C/W at 10LFM 55C ambient

 

While the design was basically on target, the thermal performance just wasn’t there to cool their RRH. ATS performed a series of experiments and, based on our data, developed a new heat sink that had these improved specifications:

17 fins

5mm base

Thermal Resistance of 1.05°C/W thermal resistance at 10LFM 55C ambient

17% fewer fins than a standard RRH HS

60% Lighter than a standard RRH HS

25% less expensive than similar solutions due to reduced material cost.

 

Here’s a comparison photo showing the two side by side; the fin spacing is clearly seen between the two:

The results are dramatic! And that’s what can happen when solid thermal analysis is applied to a natural convection problem.

How about some tools to help you in this?

There was a great article in “Power Electronics Technology” magazine by Chris Soule of Thermshield that covered this issue very nicely. You can get a copy of Chris’s article by clicking to Power Electronics at this link: “Optimize Fin Spacing, how close is too close?”

Intel has a nice article providing an example of how to do an optimized plate fin extruded thermal solution spacing calculation. Chun Howe Sim and Loh Jit Seng of Intel wrote the article and it’s a quick read. You can get your copy by clicking to EE Times here: Fanless Design for Embedded Applications

You should also review the ATS series, “How to Apply Natural Convection Cooling for the Thermal Management of Electronics” You can read our three part series here:  part 1, part 2, and part 3.

 

Finally, give us a call at 781-769-2800 or drop us an e-mail at [email protected] or submit your questions and project for natural convection cooling via our online project form on our main web site here.

We’ve heard many of our customers say to us, “if I get my technical information from qats.com, why can’t I just buy the heatsinks I choose right there too?”

Well we heard you loud and clear!

We now provide the capability for customers to directly purchase many of their heat sinks and other thermal management products directly from our website, Qats.com, for immediate shipment (see our official press release here).

We added the new e-commerce feature, which we have dubbed eSHOP, to our main website after many of our customers asked for a faster method to buy ATS heat sinks directly. Our eShop feature allows visitors to batch together orders of heat sinks and size-matched ATS heat sink attachment systems, maxiGRIP or superGRIP.

Here’s how it works: after finding the ATS heat sink that meets your application requirement, you simply click the nearby BUY NOW button to start the online purchase process, indicating quantity and if needed, adding multiple parts to a shopping cart until checkout. Shipping weight is automatically calculated and ATS offers a choice of shipping methods. Orders can be paid by credit card.

“We recognize many of our customers are short on time and need to get samples or short run production parts right away”, says Dr. Kaveh Azar, CEO of Advanced Thermal Solutions. “Our eShop feature addresses that need. Visitors can easily find the cooling products they need and quickly have them in hand to resolve their heat-related issues”.

We’re rolling out this exciting new feature in stages, so first on tap that has the eSHOP feature is our LED heat sinks, both our new STAR Series LED Heat Sinks and our Linear LED Heat Sinks. You’ll know a device has the eSHOP feature applied when you see a Q-Shopping cart next to it, such as this:What does this mean for ATS’s distribution relationships with Digi-Key, Farnell, and Elfa? Those distribution relationships are still in place and are not affected by our new feature. If you are purchasing products from distribution today with the excellent service and support our fine line of distributors offer, you should continue to do so. We support our distributors and customers 100%!

ATS heatsinks for Cavium Octeon family of CPU have been developed in close connection with Cavium.   In fact, the thermal application notes for Cavium’s CPUs were written by ATS engineers as we collaborated on development for the best thermal management.

Two of the heatsinks in particular are worth noting.  The ATS-691-C2-R1 offers up a thermal resistance of .6 C/W at 200 LFM and the ATS-725-C1-R1 offers up a thermal resistance of 2 C/W at 200 LFM.  Both are excellent choices to help jumpstart your next Cavium Octeon design.

For more information, drop us some mail at [email protected]

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