Of special interest is the work ongoing in the field of liquid metal cooling. Apart from heat pipes based on liquid metals, mainly for the high-temperature range, an increasing amount of research is devoted to the use of Ga-Sn-In eutectics that remain liquid down to minus 19°C. In [36, 37] high-performance liquid metal cooling loops are described using magneto fluid dynamic pumps, claiming over 200 W/cm2 cooling capacity, using a flow of 0.3 l/min at 15 kPa. Examples of liquid cooling loops for electronics cooling application are shown in Figures 11 and 12. Another advantage of liquid metal is its much lower CTE compared to water and the fact that freezing introduces fewer problems. Developments to extend the use in cold environments to -40°C are ongoing.