Experimental Characterization of Thin-Film Thermoelectric Based Active Cooling Modules

Improvements in electronic devices have led to increased power densities and need for small scale miniature cooling solutions. To address this issue, Defense Advanced Research Projects Agency (DARPA), Microsystems Technology Office (MTO) created the Active Cooling Modules (ACM) effort to develop technology solutions able to provide small scale (4 cm²) active high heat flux cooling of a 100W device (25 W/cm²) at a 15 °C temperature lift with Coefficient Of Performance (COP) comparable to state of the art thermoelectric coolers. Thin-film thermoelectric cooling devices are well suited to provide high heat flux active cooling. In the present work, an experimental apparatus is developed to characterize the performance of a subscale thin-film thermoelectric cooling modules 1/144^th, 1/36^th and 1/9^th the size of a full scale 4 cm² device. An in-situ calibration methodology is proposed to characterize the performance of these thermoelectric microcoolers. In this early development work, vacuum conditions are maintained to minimize thermal losses between the thermoelectric module sink and source sides. The small size of the subscale devices and vacuum conditions introduce additional uncertainties into the system and could lead to errors in COP measurement (>0.5). The additional sources of errors as the device dimensions shrink are identified and minimized leading to energy balance in the system.