Experimental Investigation of Compact Evaporators for Ultra Low Temperature Refrigeration of Microprocessors

Wadell, Robert Paul

Title:

Experimental Investigation of Compact Evaporators for Ultra Low Temperature Refrigeration of Microprocessors

dc.contributor.advisor	Joshi, Yogendra
dc.contributor.advisor	Fedorov, Andrei G.
dc.contributor.author	Wadell, Robert Paul	en_US
dc.contributor.committeeMember	Paul Kohl
dc.contributor.department	Mechanical Engineering	en_US
dc.date.accessioned	2005-09-16T15:10:01Z
dc.date.available	2005-09-16T15:10:01Z
dc.date.issued	2005-07-18	en_US
dc.description.abstract	It is well known that microprocessor performance can be improved by lowering the junction temperature. Two stage cascaded vapor compression refrigeration (VCR) is a mature, inexpensive, and reliable cooling technology that can offer chip temperatures down to ?? C. Recent studies have shown that for a power limited computer chip, there is a non-linear scaling effect that offers a 4.3X performance enhancement at ?? C. The heat transfer performance of a compact evaporator is often the bottleneck in sub-ambient heat removal. For this reason, the design of a deep sub-ambient compact evaporator is critical to the cooling system performance and has not been addressed in the literature. Four compact evaporator designs were investigated as feasible designs - a baseline case with no enhancement structures, micro channels, inline pin fin arrays, and alternating pin fin arrays. A parametric experimental investigation of four compact evaporator designs has been performed aiming at enhancing heat transfer. Each evaporator consists of oxygen free copper and has a footprint of 20 mm x 36 mm, with a total thickness of 3.1 mm. The micro channel evaporator contains 13 channels that are 400 um wide by 1.2 mm deep, and the pin fin evaporators contain approximately 80 pin fins that are 400 um wide by 1.2 mm tall with a pitch of 800 um. Two phase convective boiling of R508b refrigerant was investigated in each evaporator at flow rates of 50 - 70 g/min and saturation temperatures of ??to ??C. Pressure drop and local heat transfer measurements are reported and used to explain the performance of the various evaporator geometries. The results are compared to predictions from popular macro- and micro-channel heat transfer and pressure drop correlations. The challenges of implementing a two stage cascade VCR systems for microprocessor refrigeration are also discussed.	en_US
dc.description.degree	M.S.	en_US
dc.format.extent	6108391 bytes
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dc.identifier.uri	http://hdl.handle.net/1853/7198
dc.language.iso	en_US
dc.publisher	Georgia Institute of Technology	en_US
dc.subject	Microprocessor	en_US
dc.subject	Thermal management
dc.subject	Vapor compression refrigeration
dc.subject	Microchannels
dc.subject	Compact evaporator
dc.subject	Flow boiling
dc.subject.lcsh	Evaporative cooling	en_US
dc.subject.lcsh	Electronic apparatus and appliances Thermal properties	en_US
dc.subject.lcsh	Microprocessors	en_US
dc.title	Experimental Investigation of Compact Evaporators for Ultra Low Temperature Refrigeration of Microprocessors	en_US
dc.type	Text
dc.type.genre	Thesis
dspace.entity.type	Publication
local.contributor.advisor	Fedorov, Andrei G.
local.contributor.advisor	Joshi, Yogendra
local.contributor.corporatename	George W. Woodruff School of Mechanical Engineering
local.contributor.corporatename	College of Engineering
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