Michael Lynn Zumbrunnen

Dual-tapered piston (DTP) module cooling for IBM Enterprise System/9000 system

The water-cooled thermal conduction modules (TCMs) in the IBM Enterprise System/9000™ (ES/9000™) systems require a fourfold thermal improvement over TCMs in the 3090™ system. An examination of the thermal/mechanical tolerance relationships among the chips, substrate, and cooling hardware showed that a cylindrical piston would not meet this requirement. The piston was redesigned with a cylindrical center section and a taper on each end. This shape minimizes the gap between the piston and “hat” while retaining intimate contact between the piston face and chip surface during all assembly conditions. Numerical and analytical models demonstrate that this new piston shape, coupled with improved conductivity of the cooling hardware materials, exceeds ES/9000 system needs. These models were verified by tests conducted on single-site and full-scale modules in the laboratory and by tests on actual ES/9000 systems.