The Future Is Fanless: 100% Heat Capture for Liquid Cooled AI Servers

A sponsored article published by IEEE Spectrum on behalf of CoolIT, an Ecolab company, describes a shift toward near-total liquid heat capture in AI server racks as processor thermal design power continues to rise.

The article states that beyond 250 kW per rack, a hybrid liquid-and-air cooling approach no longer works. At that density, a 70/30 liquid-to-air split leaves a 75 kW air load, and the air cooling system needed to move it brings cost and complexity few operators will accept, according to CoolIT. The stated alternative is near-total heat capture, in which liquid takes effectively all the heat and air falls below 1 percent of the load, allowing the server to run fanless.

CoolIT says rising heat loads are cascading beyond the processor into memory, networking, storage, and power components that once ran on air. It describes its toolkit for these parts as including conductive plates, vapor chambers, heat pipes, and thermal transfer plates, along with riding coldplates for pluggable components. The article notes that peripherals vary widely in shape, size, and mounting requirements, with some running cooler and others hotter than the processor case temperature.

CoolIT says it builds server loops from modular coldplate blocks proven across six generations of fanless designs. It adds that connection reliability, coolant routing, and assembly time at rack integration affect whether a design moves into production.

As rack power climbs toward 1 MW, CoolIT's modeling places full heat capture as the standard server design for flagship rack-scale products through 2028. The article states that true 100 percent heat capture remains almost impossible in the strictest sense, making near-total capture the described target and CoolIT's claimed scale of capture.