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Subcooler for Liquid Nitrogen Cooling of Electronic Circuits With Direct Vapor Cycle Refrigeration

IP.com Disclosure Number: IPCOM000100861D
Original Publication Date: 1990-Jun-01
Included in the Prior Art Database: 2005-Mar-16
Document File: 2 page(s) / 56K

Publishing Venue

IBM

Related People

Chrysler, GM: AUTHOR [+2]

Abstract

Semiconductor chips are attached to a substrate in a row and column array, as is conventional. Nitrogen serves both as a coolant for electronic circuits and the working fluid in a liquifaction-type cryogenic refrigerator. The chips are cooled by immersion in liquid nitrogen. Cooling may be augmented by known methods, such as attachment of extended surfaces or jet impingement. One or more substrates, the liquid nitrogen, and any additional chip-cooling apparatus are packaged in a suitable enclosure. The liquid is subcooled (e.g., the saturation temperature is raised above the liquid temperature) by charging the enclosure with a small volume of non-condensible gas, so that the total pressure is the sum of the liquid's vapor pressure and the pressure of the non-condensible gas.

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Subcooler for Liquid Nitrogen Cooling of Electronic Circuits With Direct Vapor Cycle Refrigeration

       Semiconductor chips are attached to a substrate in a row
and column array, as is conventional.  Nitrogen serves both as a
coolant for electronic circuits and the working fluid in a
liquifaction-type cryogenic refrigerator.  The chips are cooled by
immersion in liquid nitrogen.  Cooling may be augmented by known
methods, such as attachment of extended surfaces or jet impingement.
One or more substrates, the liquid nitrogen, and any additional
chip-cooling apparatus are packaged in a suitable enclosure.  The
liquid is subcooled (e.g., the saturation temperature is raised above
the liquid temperature) by charging the enclosure with a small volume
of non-condensible gas, so that the total pressure is the sum of the
liquid's vapor pressure and the pressure of the non-condensible gas.
The effect of subcooling is to increase the minimum heat flux for
film boiling (CHF), thereby increasing the maximum heat flux that can
be dissipated by a chip, and to decrease the void fraction in flow
boiling cooling schemes.  Nitrogen vapor, which results from boiling
at the heated chip and extended surfaces in the enclosure, and trace
amounts of helium gas are collected and throttled to the inlet
pressure of a known cryogenic refrigerator.  The amount of
non-condensible helium entering the refrigeration loop is minimized
by collecting nitrogen vapor in a dome placed below the free...