Economic basis for evaporative cooling of electron tubes

Evaporative cooling techniques, which include nucleate boiling, subcooled boiling, and heat pipes, have been known for quite some time. As recent advances in system power increasingly emphasize economic and physical limitations of conventional methods, evaporative systems are attracting growing interest. Within their limitations, all evaporative systems are significantly more efficient than conventional methods. This paper analyzes quantitatively and compares the limitations of the two conventional and three evaporative methods in terms of economic and reliability considerations and describes current applications of evaporative cooling techniques.