Introduction

Background

Objectives


Test facilities

Diagnostic techniques







 

 
Boiling flow in microchannels

micro nano engineering
   

  Introduction

High capacity cooling systems are required to remove high heat densities generated by small-scale applications such as micro-systems, sensors and actuators and micro electronic components. Liquid cooling proved to be essential due to the better thermal transport properties of liquids but, according to the International Technology Roadmap for Semiconductors (ITRS) single-phase systems will shortly be outdated. Liquid boiling has major advantages because the use of latent heat allows reduce flow rates, the temperature of the coolant does not rise, at the same time that it allows achieving higher heat transfer coefficients.

In this context, current development of thermal control technologies consider the circulation of the working fluid by a micro-pump to remove heat, which is then transferred to a heat sink conveniently located, in order to reject the heat to an external radiator by a thermal control system. However, major thermal resistances appear between the junction and the surface of the heat exchanger and from the heat sink to the primary coolant which lead to thermal limitations. Therefore, surface cooling will not be sufficient to support increased power and heat-generation densities predicted in the ITRS. In this context, in addition to power electronic integration, internal cooling system integration is a possible solution to thermal problems which needs to be considered. On the other hand, integrated power electronics system requires advances in technologies, which depend upon finding solutions to deal with the multi-disciplinary issues in thermal management, micro/nano technologies, materials, electromagnetic compatibility and environmental concerns. We attempt to contribute to this drive by exploring advanced possibilities to reduce operating temperatures at a given power.