{"id":217,"date":"2010-03-12T16:36:48","date_gmt":"2010-03-12T21:36:48","guid":{"rendered":"http:\/\/heatsinks.wordpress.com\/?p=217"},"modified":"2016-02-19T15:09:37","modified_gmt":"2016-02-19T19:09:37","slug":"using-pre-heated-air-or-blocking-your-fans-air-flow-just-dont-do-it","status":"publish","type":"post","link":"https:\/\/www.qats.com\/cms\/2010\/03\/12\/using-pre-heated-air-or-blocking-your-fans-air-flow-just-dont-do-it\/","title":{"rendered":"Using pre-heated air or blocking your fans air flow:  just don&#8217;t do it!!"},"content":{"rendered":"<p><a href=\"http:\/\/www.flickr.com\/photos\/18536761@N00\/\"><img loading=\"lazy\" decoding=\"async\" class=\"alignnone size-medium wp-image-218\" title=\"burnt_computer\" src=\"http:\/\/heatsinks.files.wordpress.com\/2010\/03\/burnt_computer.jpg?w=199\" alt=\"\" width=\"199\" height=\"300\" \/><\/a> Please, please don&#8217;t use pre-heated air in your thermal designs and PLEASE simulate the design using CFD or at least have a nice, calm chat with your mechanical\/thermal team prior to design freeze on your electrical layout.\u00c2\u00a0\u00c2\u00a0 Once a design gets locked down the thermal design options start to get limited or expensive or ugly.\u00c2\u00a0 Or all three!<\/p>\n<p>Here&#8217;s what we&#8217;d like our readers to do instead:<\/p>\n<ul>\n<li>Do have a nice chat with the EE and ME team together.\u00c2\u00a0 Maybe bring some bagels and make it peaceful.<\/li>\n<li>Do some quick look over of any designs for obvious issues, like, walls of memory in front of hot cpus.\u00c2\u00a0\u00c2\u00a0 Yes, as ME&#8217;s and Thermal Engineers we understand that there are ever sticter rules in layout and routing of high speed memory buses.\u00c2\u00a0 BUT, let&#8217;s compromise together so we can keep them happy and cool \ud83d\ude42<\/li>\n<li>Do some first order modeling, on paper or a spreadsheet.\u00c2\u00a0 How do things look relative to your thermal budget? (please click to <a href=\"http:\/\/new.qats.com\/qpedia\/Qpedia_0308_First_Order_Thermal_Model.pdf\">our nice white paper on how to do first order thermal modeling<\/a> if you need a reminder)<\/li>\n<li>Then, as the EE design gets placed out, maybe do some CFD to see how everything looks thermally.<\/li>\n<\/ul>\n<p>While this seems like it&#8217;ll add a week to your design, it won&#8217;t.\u00c2\u00a0 Maybe two or three days and the end result is a less expensive design that is:<\/p>\n<ul>\n<li>More reliable with higher MTBF<\/li>\n<li>Operates at the maximum frequencies<\/li>\n<li>Is safer<\/li>\n<\/ul>\n<p>Robin Bornoff, a Product Manager at Flomerics UK (now Mentor Graphics), has some great thoughts on this topic.\u00c2\u00a0 We&#8217;d recommend having a read of her article, &#8220;<a href=\"http:\/\/heatsinks.files.wordpress.com\/2010\/03\/get_on_board_solving_thermal_problems.pdf\">Get On Board: Solving Thermal Problems at Board Level<\/a>&#8220;.<\/p>\n","protected":false},"excerpt":{"rendered":"<p>Please, please don&#8217;t use pre-heated air in your thermal designs and PLEASE simulate the design using CFD or at least have a nice, calm chat with your mechanical\/thermal team prior to design freeze on your electrical layout.\u00c2\u00a0\u00c2\u00a0 Once a design &hellip; <a href=\"https:\/\/www.qats.com\/cms\/2010\/03\/12\/using-pre-heated-air-or-blocking-your-fans-air-flow-just-dont-do-it\/\">Continue reading <span class=\"meta-nav\">&rarr;<\/span><\/a><\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[30,59],"tags":[],"class_list":["post-217","post","type-post","status-publish","format-standard","hentry","category-heat-sinks","category-thermal-design"],"_links":{"self":[{"href":"https:\/\/www.qats.com\/cms\/wp-json\/wp\/v2\/posts\/217","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\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/www.qats.com\/cms\/wp-json\/wp\/v2\/comments?post=217"}],"version-history":[{"count":0,"href":"https:\/\/www.qats.com\/cms\/wp-json\/wp\/v2\/posts\/217\/revisions"}],"wp:attachment":[{"href":"https:\/\/www.qats.com\/cms\/wp-json\/wp\/v2\/media?parent=217"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.qats.com\/cms\/wp-json\/wp\/v2\/categories?post=217"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.qats.com\/cms\/wp-json\/wp\/v2\/tags?post=217"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}