A Micro-Scale Membrane-Actuated Condenser/Evaporator for Enhanced Thermal Management

There is a strong need to improve our current capabilities in thermal management and electronic cooling. The present study investigates the feasibility of a micro-scale membrane-actuated dropwise condenser/evaporator. An actuated membrane is adopted as the droplet condensing and ejecting device. Droplets with appropriate dimensions and frequencies are formed and ejected for efficient cooling. The present system requires no mechanical moving parts, and hence is reliable. In addition, it needs little maintenance due to closed recirculation, exhibits favorable packaging scalability in view of the modular concept, and offers high energy transfer effectiveness. In this work, we outline the thermodynamic consideration based on a vapor-compression cycle to assess the performance of such a device. The coefficient of performance of the cycle is estimated for four different fluids: water, R12, R134a and FC-72. The system design parameters and operating performances are estimated for droplet sizes ranging from 10 to 500 micrometers. It is demonstrated that in this operating range, the gravity effect is small, making this device ideal for both earth-bound and spacecraft applications.