MEMS silicon-based micro-evaporator

An increase in the energy density in device miniaturization and chemical process intensification generates intense local heating. Properly designed devices for heat absorption, such as evaporators, are essential for dealing with high heat fluxes. This paper presents a miniaturized evaporator with fin structure fabricated in silicon with microelectromechanical systems (MEMS) technology. The aim of the presented micro-evaporator is to achieve a maximum cooling capacity and operation stability at very small liquid flow rates (of the order of 1–5 ml h−1). Devices with high aspect ratio channels (10 and 20 µm wide, 100 µm deep) are sealed with glass by anodic wafer bonding and tested with de-ionized water as coolant. An embedded bulk silicon heater which mimics external heat sources also acts as a temperature sensor. Optimizations of the fin-channel structure lead to more stable operations. Absorbed power fluxes are up to 40 W cm−2 for a fluid flow of 5 ml h−1.