Nvidia cools data centers with liquid warmer than hot tub water. This is precisely how it saves electricity and water

When computer cooling is mentioned, most people think of fans blowing in cold air, although liquid cooling is, of course, far more popular today. Nvidia is taking precisely this second path for its AI data centers – the chips within them are surrounded by liquid heated to almost hot tub temperature. And surprisingly, it is precisely in this seemingly absurd temperature that enormous savings in energy and water are hidden.

Cold Air is Expensive. Warm Liquid is Not

Traditional data centers are air-cooled: large air conditioners and fans push cold air between servers and dissipate heat. However, this cooling consumes up to 40% of all electricity a data center uses. And the colder you want the air, the more power it consumes.

That’s why the company relies on so-called direct liquid cooling. Simply put: a metal plate sits on each chip, through which coolant flows, drawing heat directly from the source. The entire circuit is closed and operates without a single fan. The liquid enters the processors heated to up to 45 °C and leaves at around 55 °C – not icy, but distinctly warm.

Why Warmer Coolant is More Efficient

When the coolant only needs to be lukewarm, energy-intensive chillers don’t have to laboriously overcool it – outdoor air can dissipate the heat directly from it in favorable weather. According to Nvidia, simple math applies: every degree the coolant is allowed to be warmer reduces cooling costs by approximately 4%. At temperatures around 45 °C, the savings add up nicely.

The figures boasted by the manufacturer are impressive – although, of course, we cannot independently verify their calculations. A data center with a 50-megawatt input is expected to save over four million dollars annually on electricity and water thanks to warm cooling. And water is the second big win.

Nvidia Also Saves Water and Quiets the Entire Hall

Conventional cooling evaporates enormous amounts of water – millions of liters annually per megawatt of power. A closed circuit here practically consumes no water. “We’ve eliminated a huge amount of energy consumption and essentially all water consumption,” says Ali Heydari, who is in charge of data center cooling at Nvidia.

Warm cooling also has pleasant side effects. Without fans, their continuous hum, which approaches 85 decibels in the halls, disappears. Furthermore, servers can be packed closer together – instead of six racks, two are now reportedly sufficient. According to the company, the Rubin chip generation is to be the very first to be 100% liquid-cooled. And the waste heat that used to dissipate into the air can now, for example, heat surrounding buildings.

Were you surprised that warmer coolant can be more efficient than cold coolant?

Sources: Nvidia, The Verge