A comparison is made between the expansion process in the vortex tube and that in the expansion turbine and the throttle valve,thereby the unique features and advantages of the new technology are demonstrated by means of an example of treating natural gas with a vortex tube and a closed energy-cyclic system.

After a discussion on the presentcooling techniques of power electronic devices conducted, it is concluded that the full-closed de-ion water-cooling is thebest cooling technology since it can allow highest power dissipations, which covers more than foreseen needs for HPEE.