{"id":1587,"date":"2010-09-08T08:37:55","date_gmt":"2010-09-08T12:37:55","guid":{"rendered":"http:\/\/heatsinks.wordpress.com\/?p=1587"},"modified":"2018-04-16T09:33:43","modified_gmt":"2018-04-16T13:33:43","slug":"how-heat-sink-fin-spacing-plays-a-key-role-in-natural-convection-cooling-and-how-you-can-optimize-it","status":"publish","type":"post","link":"https:\/\/www.qats.com\/cms\/2010\/09\/08\/how-heat-sink-fin-spacing-plays-a-key-role-in-natural-convection-cooling-and-how-you-can-optimize-it\/","title":{"rendered":"How heat sink fin spacing plays a key role in natural convection cooling and how you can optimize it"},"content":{"rendered":"

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.<\/p>\n

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:<\/p>\n

\"straight<\/a><\/p>\n

Here we see that the “B” dimension is the channel width or the fin spacing of this heat sink.<\/p>\n

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\u00a0 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!\u00a0 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.\u00a0 One case in particular was very interesting<\/p>\n

The project we were working on was\u00a0 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:<\/p>\n

\n
35 Fins<\/div>\n
5mm base<\/div>\n
Thermal Resistance of 1.39 C\/W at 10LFM 55C ambient<\/div>\n

 <\/p>\n

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:<\/div>\n
\n

<\/p>\n

\n
17 fins<\/div>\n
5mm base<\/div>\n
Thermal Resistance of 1.05\u00b0C\/W thermal resistance at 10LFM 55C ambient<\/div>\n
17% fewer fins than a standard RRH HS<\/div>\n
60% Lighter than a standard RRH HS<\/div>\n
25% less expensive than similar solutions due to reduced material cost.<\/div>\n

 <\/p>\n<\/div>\n

Here’s a comparison photo showing the two side by side; the fin spacing is clearly seen between the two:<\/div>\n<\/div>\n
\"aluminum<\/a>\"aluminum<\/a><\/div>\n
The results are dramatic! And that’s what can happen when solid thermal analysis is applied to a natural convection problem.<\/div>\n
\n

How about some tools to help you in this?<\/p>\n

There was a great article in “Power Electronics Technology<\/a>” magazine by Chris Soule of Thermshield<\/a> 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?<\/a>”<\/p>\n

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<\/a> here: Fanless Design for Embedded Applications<\/a><\/p>\n<\/div>\n

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:\u00a0 part 1<\/a>, part 2<\/a>, and part 3<\/a>.<\/div>\n

 <\/p>\n

Finally, give us a call at 781-769-2800 or drop us an e-mail at ats-hq@qats.com<\/a> or submit your questions and project for natural convection cooling via our online project form on our main web site here<\/a>.<\/div>\n<\/div>\n","protected":false},"excerpt":{"rendered":"

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 … Continue reading →<\/span><\/a><\/p>\n","protected":false},"author":5,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[26],"tags":[],"class_list":["post-1587","post","type-post","status-publish","format-standard","hentry","category-heat-sink"],"_links":{"self":[{"href":"https:\/\/www.qats.com\/cms\/wp-json\/wp\/v2\/posts\/1587","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.qats.com\/cms\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.qats.com\/cms\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.qats.com\/cms\/wp-json\/wp\/v2\/users\/5"}],"replies":[{"embeddable":true,"href":"https:\/\/www.qats.com\/cms\/wp-json\/wp\/v2\/comments?post=1587"}],"version-history":[{"count":3,"href":"https:\/\/www.qats.com\/cms\/wp-json\/wp\/v2\/posts\/1587\/revisions"}],"predecessor-version":[{"id":8865,"href":"https:\/\/www.qats.com\/cms\/wp-json\/wp\/v2\/posts\/1587\/revisions\/8865"}],"wp:attachment":[{"href":"https:\/\/www.qats.com\/cms\/wp-json\/wp\/v2\/media?parent=1587"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.qats.com\/cms\/wp-json\/wp\/v2\/categories?post=1587"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.qats.com\/cms\/wp-json\/wp\/v2\/tags?post=1587"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}