Thermal management at microscale level: Detailed study on the development of a micro loop heat pipe

This study aims to address the problem of removing excessive heat generated in electronic and microfluidic systems. For this purpose, a new design of a micro loop heat pipe is proposed. It is fabricated on a 2-inch silicon wafer, having a cross-section of 35 mm × 17 mm and an overall device depth of 150 μm. Experimental investigations showed that the proposed design has a low heat leak (undesirable heat conduction from the evaporator to the compensation chamber) compared to the various micro heat pipe designs presented in the literature. A temperature reduction of 28.6 °C at 3.78 W heat load is recorded using methanol as a working fluid. This study also reveals that the present methodologies to select working fluids for conventional loop heat pipes cannot be applied to micro loop heat pipes. Hence, a new methodology is proposed for the same, based on four parameters of the working fluid: cooling capacity, dry-out limit, operation in anti-gravity regimes, and force exerted on the evaporator.