Japan's AI data center boom is pushing companies toward liquid cooling， because hot GPU racks are now outgrowing the limits of air-conditioned server rooms.

Cooling already uses 30% to 40% of data center electricity， and GPU heat has more than doubled in 5 years， so Japan's Fuji Electric， Nidec， Mitsubishi Heavy， and others are chasing systems that move heat through liquid instead of air.

The weak point of normal air cooling is that air carries heat poorly， so the system needs a lot of fan power， large airflow paths， cold aisles， hot aisles， and big chillers to keep the room temperature under control.

Liquid cooling changes the target： instead of trying to cool the whole room first， it puts a cold metal plate directly on the GPU or CPU.