Energy-Efficient Piezoelectric MEMS Cooling Chip for Compact Electronics Based on a Partially Mechanical Decoupled Actuator

Compact electronics, such as smartphones and tablets, face significant overheating issues; these issues are a byproduct of enhanced performance. However, thermal management in these devices still primarily relies on inefficient passive cooling methods since today’s active cooling solutions fail to meet the stringent size and power consumption requirements. To address this difficulty, in this work, a piezoelectric micromachined synthetic jet (SJ) air cooling chip is introduced. The active cooler features a small footprint of $6\times 6.7\times 2.1$ mm and a low power consumption of only 69 mW; this value is approximately one-fourth that of a typical fan. Moreover, the cooler has a convective heat transfer coefficient as high as 72 W/m2K, and the cooling coefficient of performance (COP) is the highest among all competing miniaturized air coolers. In device design, the piezoelectric actuator adopts a partially mechanical decoupled structure, enabling effective generation of an SJ with a restricted area; in the working mechanism, the pulsating nature of the SJ and its vertical impingement on the target ensures sufficient disturbance of the thermal boundary layer. The microscale cooling technology has emerged because of its minimal size, high energy efficiency, and substantial cooling capacity and shows significant promise for the active cooling of compact electronics.