Abstract: A liquid heat sink is provided that employs natural convection of a liquid coolant (18') to cool a printed circuit board (14) on which are mounted a plurality of heat-generating components (12). In particular, the spacing d between the heat-generating components and a cold plate (20) used to cool the liquid must be such as to provide a Rayleigh number of at least about 1700 in the Rayleigh equation: ##EQU1## In the above equation, g is the acceleration of gravity, .beta. is the volumetric coefficient of expansion of the liquid coolant, T.sub.1 is the temperature of the cold plate, T.sub.2 is the temperature of the component to be cooled, .nu. is the kinematic viscosity of the liquid coolant, and .alpha. is the thermal diffusivity of the liquid coolant.

Abstract: A heat pipe structure is incorporated directly into the metal baseplate of a circuit card thereby eliminating thermal contact resistance between the baseplate and the heat pipe assembly. Components are mounted on a copper circuit layer bonded to a dielectric layer in a first portion of the baseplate with a second portion of the baseplate/heat pipe assembly extending into a heat sink/cold plate condensing area for removal of heat generated in the component portion.

Abstract: A heat transfer device for use with a heat sink in removing thermal energy from an integrated circuit chip. The inventive device includes a first membrane of flexible, thermally conductive material having a first surface in contact with the integrated circuit chip. A flexible, thermally conductive radial finger contact spring is disposed in contact with a second surface of the first membrane. A second membrane of flexible, thermally conductive material is included. The second membrane has a first surface in contact with the spring and a second surface in contact with the heat sink.