An article published by IEEE Spectrum and sponsored by cooling vendor CoolIT makes the case that AI server racks are outgrowing hybrid cooling. Once a rack passes 250 kW, the piece argues, a combination of liquid and air can no longer handle the heat load.
At that density, a 70/30 liquid-to-air split still leaves 75 kW of heat that must be removed by air. Moving that much air requires bulky cooling systems, and those systems drive up both cost and mechanical complexity.
The article's conclusion is that the future is fanless: liquid should capture 100% of the heat. That would mean eliminating air cooling entirely for the highest-density AI servers, a shift with major implications for rack design and data center deployment.