# Fans (air-cooled servers, hybrid trays)

Part ID: 4.13 · Layer 4 (Servers, racks & integration)

The axial and centrifugal fans mounted in server chassis and rack trays that move air across heatsinks and boards, still needed even in racks that use liquid cooling for the highest-power chips.

Tray and chassis fans sit alongside the heatsinks and vapor chambers (4.17) as the air-cooling half of a rack's thermal design, and they remain necessary even in a liquid-cooled rack-scale system, since cold plates (layer 5) typically cool only the GPUs and a few other hot components while the rest of the tray — memory, VRMs, networking silicon — still relies on airflow. That makes fans a hybrid-cooling-era component: as more of a rack's heat load moves to liquid, fan count per tray can fall, but it doesn't go to zero, and the fans that remain often have to move air through a more crowded, liquid-plumbed chassis than before. For investors, this is a mature, competitive component category without a strong bottleneck, so the more relevant question is the net demand trajectory as liquid cooling adoption rises — fewer fans per liquid-cooled tray, but more total trays being built.

**AI delta:** Even in a liquid-cooled rack, cold plates typically cool only the GPUs, so fans remain necessary for memory, VRMs and networking silicon on the same tray, making air-cooling components a hybrid-era holdover rather than something liquid cooling eliminates outright.

## Companies

| Company | Role | Confidence | Ownership | Ticker | Note |
|---|---|---|---|---|---|
| AVC | manufacturer | inferred | public | 3017.TW |  |
| Delta Electronics | manufacturer | inferred | public | 2308.TW |  |
| Foxconn (Hon Hai) | manufacturer | inferred | public | 2317.TW |  |
| Nidec | manufacturer | inferred | public | 6594.T |  |
| Sanyo Denki | manufacturer | inferred | public | 6516.T |  |
| Sunon | manufacturer | inferred | public | 2421.TW |  |
| Cooler Master | manufacturer | inferred | private |  |  |
| ebm-papst | manufacturer | inferred | private |  |  |

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