Experimental seismic performance for liquid immersion cooling system

Author: Noemi Bonessio, Founder, METAseismic Collection: 2023 Global Summit - Cooling Environments

Summary

Noemi Bonessio (METAseismic) presented the results of the first seismic certification test of a liquid immersion cooling unit, conducted in collaboration with Hyper-tech, Sub-mere, and Wyoming Hyperscale as OCP community partners. The test addressed a previously unresolved gap: while air-cooled IT enclosures have well-established seismic certification standards (including Zone 4 NEBS GR-63 Telcordia certification), no standards or procedures existed for liquid immersion cooling systems. The fundamental challenge is that traditional seismic protection for IT equipment relies on rigid bolting to the floor and rack reinforcement, but an immersion tank containing 250 gallons of dielectric fluid cannot be treated as a rigid structure — the fluid will slosh, potentially spilling, and the sloshing dynamics change the effective mass and vibration behavior of the system.

METAseismic developed a passive vibration isolation base (the "METAseismic base" or "METAseismic layer") using meta-materials and computational algorithms originally developed at a University of California seismic research lab. The material filters seismic energy at the base of the equipment — neither the tank nor the floor is bolted through the layer; the layer rests between them. In the longitudinal test, the METAseismic layer filtered more than 90% of damaging energy, preventing it from entering the tank. The test was performed on a triaxial shake table per NEBS GR-63 Zone 4 requirements, which simulate a magnitude-8.3 earthquake producing up to 5G acceleration forces at 0.1–0.4 seconds in the frequency band where energy is highest.

The test monitored: structural integrity of the tank, server performance (functionality tests before/during/after each shake), temperature readings throughout (to detect cooling degradation), fluid sloshing via internal cameras, and vibration data from accelerometers at the base, midpoint, and top of the pod. All functional tests showed no performance degradation or temperature variation. No structural damage was observed in tank or server mechanical components. The transmissibility curves (ratio of output to input acceleration across frequency) remained below unity in the critical frequency bands, confirming that the METAseismic base absorbed rather than amplified the input energy. The presenter concluded that this pilot establishes the first step toward standardized seismic certification procedures for liquid immersion cooling systems.