A system and method for cooling electronic devices disposed with the inner volume of a fluid-tight sealed enclosure. Thermally conductive fluids that fill one or more volumes of said sealed enclosure may be circulated away from said sealed enclosure to an external heat exchange mechanism. The inner volume of the sealed container contains one or more single phase or multi-phase thermally conductive fluids and may contain solid or sealed hollow structures that conform to or occupy space between said electronic devices. Pressure balancing mechanisms may be included to maintain suitable pressure of gaseous fluid in a volume of the sealed container.