A novel hybrid cooling scheme is proposed to remove non-uniform heat flux in real time from the microprocessor. It consists of a liquid cooled microchannel heat sink to remove the lower background heat flux and superlattice coolers to dissipate the high heat flux present at the hotspots. Superlattice coolers (SLC) are solid-state devices, which work on thermoelectric effect, and provide localized cooling for hotspots. SLCs offer some unique advantage over conventional cooling solutions. They are CMOS compatible and can be easily fabricated in any shape or size. They are more reliable as they don't contain any moving parts. They can remove high heat flux from localized regions and provide faster time response. Experimental devices are fabricated to characterize the steady-state, as well as transient performance, of the hybrid cooling scheme. Performance of the hybrid cooling scheme has been examined under various operating conditions. Effects of various geometric parameters have also been thoroughly studied. Heat flux in excess of 300 W/cm² has been successfully dissipated from localized hotspots. Maximum cooling at the hotspot is observed to be more than 6 K. Parasitic heat transfer to the superlattice cooler drastically affects its performance. Thermal resistance between ground electrode and heat sink, as well as thermal resistance between ground electrode and superlattice cooler, affect the parasitic heat transfer from to the superlattice cooler. Two different test devices are fabricated specifically to examine the effect of both thermal resistances. An electro-thermal model is developed to study the thermal coupling between two superlattice coolers. Thermal coupling significantly affects the performance of an array of superlattice coolers. Several operating parameters (activation current, location of ground electrode, choice of working fluid) affect thermal coupling between superlattice coolers, which has been computationally as well as experimentally studied. Transient response of the superlattice cooler has also been examined through experiments and computational modeling. Response time of the superlattice cooler has been reported to be less than 35 µs.
| Identifer | oai:union.ndltd.org:GATECH/oai:smartech.gatech.edu:1853/45817 |
| Date | 31 August 2011 |
| Creators | Sahu, Vivek |
| Publisher | Georgia Institute of Technology |
| Source Sets | Georgia Tech Electronic Thesis and Dissertation Archive |
| Detected Language | English |
| Type | Dissertation |
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