alt Hacker NewsWater use isn't a myth.
Our data center is mostly air-cooled, with 100F hot aisles and chilled water going to heat exchangers in every third rack position, although some of our newer GPU racks use chilled water directly. For most of the year that means we don't need chillers - the warm water return is sufficiently hotter than outdoor temp that heat "flows downhill" with a bit of pumping.
But we use an evaporative cooler to carry that heat away outside, because it's more efficient. If you look up the heat of vaporization of water, that means we evaporate about 10,000 gallons of water per day per megawatt of power dissipated. We're on canal off a large river, and we don't dissipate all that many megawatts, so I believe the water use isn't significant.
Using air as the working fluid to draw heat from your machines has a limitation - humans have to breathe that air whenever they work on the equipment, so the temperature is limited. Once the exterior temperature nears your hot aisle air temp, you either need active A/C to create a heat source hotter than ambient, or an evaporative cooler to lower the "effective" ambient temp to the dew point.
Liquid cooling lets you run your working fluid a lot hotter without killing folks like me who go into the data center, although honestly 45C sounds like an incremental improvement over the 100F places like ours are already running. (although to be fair, the warm water return from the heat exchangers is no doubt somewhat less than 100F) It also lets you run your "cold" side a lot hotter - if you "chill" your water down to 100F (38C) on a hot day, it's still cold enough to carry away a lot of heat at 45C.
(I'm skipping over the fact that there are multiple heat exchanger loops involved - e.g. any system with an evaporative cooler needs a heat exchanger to keep leaves and bird shit outside the building where it belongs)
May I ask where this datacenter you're referring to is located? State and country would be super helpful.
I disagree if there is an assumption or premise that all datacenters use water for cooling. Datacenters are not built or operated the same, nor have a requirement for water cooling, or evaporative cooling.
Water use is partially a myth for sure, because it's not a certainty or requirement in every datacenter, ever.
If water is used for evaporative cooling, it's used in places that the cooling can't work above a certain temperature. Say, for example the US where it gets over 120 degrees farenheit.
The inability for cooling equipment to perform when it's extremely hot might be supplemented my multiple technologies cooling together, including evaporative cooling. So evaporative cooling might be common in the US or other regions like it.
There are many datacenters that don't need to consume water at all for cooling, except for a water cooler to drink from, and sprinkler systems for fire suppression. They are engineered and cooled just fine.
The demand for datacenters and money in this space will likely solve the water usage, if for no other reason, than to increase flexibility of locations.
If anyone is curious a bit more about how:
Datacenters locations optimize 3 main factors.. Power, Cooling, and Fibre.
We know the climate of location isn't the same everywhere in the world where datacenters are located.
One thing that can get missed among the water hyperventilating crowd is that datacenters are designed for the need of the location's climate, and what it takes to cool. Too many folks spreading the information are usually non-technical, and get their education about datacenters from social media.
There are many places in the world, including in Canada, where cooling is built in 6 months of the year to outdoor air. The temperature isn't high enough in the summer to warrant or require evaporative cooling. They can just vent outside, or capture the heat for other purposes.
In other areas still, proven building approaches such as countersinking the datacenter for some additional geothermal benefit, local power generation (Solar, Natural gas) and a unique path to the same datacenter is possible.
Of course, if foreign companies are wanting to build in a different country, they might by default build how they know for their region and assume it's ok.
There is a massive build out of datacenters occurring in Canada right now, they will be built according to how buildings are built in that climate, not importing cooling technology from regions where it's too hot, or evaporative cooling is the only, or most available option. In temperate climates, considerations have to be made for keeping keep buildings warm (not just cool) year round.
The nice thing is this is not hypothetical.
There is of course, equipment that can have liquid cooling, or we see those fun videos of equipment submerged in liquid operating. These seem to not be the common.