Hi Brad, Et. Al. Regarding #2, you may consider graphite/carbon foam. It has a thermal conductivity equivalent of copper/alum, but essentially no thermal mass; an excellent conductor of heat. It also weighs substantially less. Koppers [1] and Poco Graphite [2] are licensed manufacturers of this ORNL invention [3].
Good luck on your project, it sounds like a great one. -bogdan Bogdan Vacaliuc Data Acquisition Group/Research Accelerator Division Spallation Neutron Source One Bethel Valley Road, P.O. Box 2008, MS-6476 Oak Ridge, TN 37831 603-591-2458 cell [1] http://www.kfoam.com/material.htm [2] http://www.poco.com/tabid/95/Default.aspx [3] http://www.ornl.gov/adm/partnerships/success_stories/led_foam.shtml From: dana whitlow <[email protected]<mailto:[email protected]>> Date: Tuesday, April 16, 2013 7:28 AM To: Francois Kapp <[email protected]<mailto:[email protected]>> Cc: "[email protected]<mailto:[email protected]>" <[email protected]<mailto:[email protected]>>, Vaughan Moss <[email protected]<mailto:[email protected]>>, Steve Maher <[email protected]<mailto:[email protected]>> Subject: Re: [casper] Roach Conduction Cooling It seems to me there are two problems here: 1. Getting rid of the heat altogether, and from the comments I've seen, that will apparently need to be by radiation. "In space, no one can..." Merely dunking things in liquid will just get you hot liquid. And I'd be concerned about the chip packages' leak integrity. 2. Also you need to carry the heat from source to the radiator without excessive temperature difference. My point is, don't forget the radiator. Then ask, perhaps, "Can I just attach the chips to the radiator?". Perhaps this is already what Jason is getting at, but he didn't say how his "heatsink" was going to dispose of the heat. Dana Whitlow Arecibo Observatory. On 4/16/2013 7:03 AM, Francois Kapp wrote: Hi Brad, Given it's a balloon payload, what are your mass constraints? Conductive cooling is going to involve throwing metal at the problem, possibly a lot of metal... -Francois On Tue, Apr 16, 2013 at 12:57 PM, Steve Maher <[email protected]<mailto:[email protected]>> wrote: Heatpipes and dunking <http://www.pugetsystems.com/submerged.php> in liquid (e.g. mineral oil) are options we've explored (with PCs), although we seem to be favoring pressure vessels at this point. Steve On Tue, Apr 16, 2013 at 2:34 AM, Jason Manley <[email protected]<mailto:[email protected]>> wrote: I don't know of anyone who's actually done this, but we do also have a passive-cooled concept for our new digitiser board (loosely based on ROACH2). We've been thinking about a prototype that'd essentially be turning a ROACH2 board upside-down and bolting it onto a giant metal plate that's been appropriately milled out of a solid chunk of alu. The FPGA, PPC, QDR and other hot bits would make contact with the plate and use it as heatsink. The other high-profile parts (RAM DIMM, for example) needs holes or cavities milled out the alu. I think Vaughan (cc'd here) might have some mechanical drawings of ROACH2 with the holes and things in the appropriate place. It might help you get started. He could also provide some CFD models and heat load measurements of the various components. Jason Manley DSP Specialist SKA-SA Cell: +27 82 662 7726<tel:%2B27%2082%20662%207726> Work: +27 21 506 7300<tel:%2B27%2021%20506%207300> On 15 Apr 2013, at 20:29, Brad Dober wrote: > Dear Casper Collaboration Members, > > My name is Brad Dober, and I'm a grad student at UPenn working on a > ROACH-based MKID readout for a balloon payload. At our float altitude, > air-cooling the ROACH and ADC/DACs isn't feasible Has any other group looked > into or even designed a conduction-cooled system for .either the ROACH1 or > ROACH2? > > Any leads would be extremely helpful. > > Sincerely, > > Brad Dober > Ph.D. Candidate > Department of Physics and Astronomy > University of Pennsylvania > Cell: 262-949-4668<tel:262-949-4668> -- Francois Kapp Sub-system Manager Digital Back End meerKAT SKA South Africa Third Floor The Park Park Road (off Alexandra Road) Pinelands 7405 Western Cape South Africa Latitude: -33.94329 (South); Longitude: 18.48945 (East). (p) +27 (0)21 506 7300 (p) +27 (0)21 506 7360 (direct) (f) +27 (0)21 506 7375 (m) +27 (0)82 787 8407
