# Immersion cooling systems

Part ID: 5.08 · Layer 5 (Liquid cooling (IT-side: chip to CDU))

Systems that submerge servers or trays directly in a dielectric fluid, either in open tanks (single-phase) or sealed chambers where the fluid boils and recondenses (two-phase), to cool the whole tray rather than individual dies.

Immersion cooling replaces the cold-plate-and-manifold chain entirely: instead of routing coolant to each die through a plate, the whole server tray sits in a bath of dielectric fluid that carries heat away by direct contact. Single-phase systems keep the fluid liquid throughout and rely on pumps and heat exchangers to move heat out of the tank; two-phase systems let the fluid boil at the hot surfaces and recondense at a coil, using the phase change itself to move heat more efficiently. It is a different mechanical and facility design from the rack-based direct-to-chip chain used elsewhere in this layer — servers and racks built for immersion need different chassis, connectors, and serviceability approaches, and retrofitting an existing air-cooled or direct-to-chip hall for immersion is a bigger undertaking than adding cold plates. Adoption has concentrated in specific use cases rather than becoming the default alongside direct-to-chip. Investors should watch it as a higher-conviction, narrower bet than direct-to-chip cooling: fewer vendors, less standardization, and adoption tied to specific operators and use cases rather than broad industry uptake.

## Companies

| Company | Role | Confidence | Ownership | Ticker | Note |
|---|---|---|---|---|---|
| Asperitas | manufacturer | inferred | private |  |  |
| Firmus (Sustainable Metal Cloud) | manufacturer | inferred | private |  |  |
| GRC | manufacturer | inferred | private |  |  |
| Hypertec | manufacturer | inferred | private |  |  |
| Iceotope | manufacturer | inferred | private |  |  |
| LiquidStack | manufacturer | inferred | private |  |  |
| Midas | manufacturer | inferred | private |  |  |
| Submer | manufacturer | inferred | private |  |  |
| TMGcore | manufacturer | inferred | private |  |  |

Confidence tags: disclosed = company/filing statement; reported = trade press or partner list; inferred = taxonomy lead.