Power dissipated by modern microprocessors is a function of time and continuously changes with the workload, giving rise to temporal hotspots of local areas with very high power dissipation. A hybrid cooling scheme has been proposed, which combines solid-state cooling to remove the dynamically changing hotspots in real time while addressing the steady-state background power dissipation using liquid cooling in embedded microchannels. In this paper, we have investigated the transient behavior of the hybrid scheme through experiments as well as computational modeling. Infrared microscopy, equipped with transient detector, was used to study the transient cooling behavior when a power spike is produced by a microfabricated heater, emulating a hot spot. The results indicate that solid-state superlattice cooling (SLC) offers an extremely fast transient response, having time constant of the order of few tens of microseconds which matches with dynamics of microprocessor power dissipation. The effect of various geometric and operating conditions on the transient behavior of the hybrid scheme has been assessed to provide an insight and guidelines for optimal design and operation of the proposed hybrid cooling scheme.

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