I wrote this in another reply here, but from this article and others I've read on Space X's/Tesla's datacenters, it's the use of turbine generators that cause that enormous whine sound. (Note how similar it is to a jet engine.) I live in Ashburn, where we have datacenters all over the place. But none of them sound like this. At worst, we get a dull hum, much lower in volume, if the air handlers are working especially hard. But you need to be on top of them to hear that.

Ashburn has the infrastructure however. From what I'm reading, other places don't. So they bring in power on-site, and it seems to be much less regulated.

A lot of hyperscale data centers, often built for ai, are built cheaply so there is no CRAC air conditioner nor any other air conditioners using refrigerant (direct expansion air conditioners) nor air or water cooled chillers. As air enters the building, it passes though electrostatic filters to remove dust, then through evaporative coolers which spray water to cool the air and then directly into the cold aisles in the data hall. Then The hot aisles are vented directly to the atmosphere through the roof. The server fans are very loud and can be heard outside.

I think in this case it's HVAC?

Edit: the noise at many of these DCs are also "portable" natural gas turbines, intended for use as emergency power or temporary power at large events. But companies like xAI are using them to back-door build large power plants. xAI's memphis DC has 30+ turbines running non-stop and xAI never filed any paperwork or received any permits related to them.

AI DCs use enormous amounts of power (and thus generate enormous amounts of heat) compared to "traditional" DCs. We're talking hundreds of megawatts, sometimes gigawatts. 1GW DCs have been popping up already.

OpenAI is planning a 10GW facility in Ohio that will need its own natural gas power plant. A 10GW natural gas power plant is massive. Currently the largest NG combined-cycle power plant in the US is about 3-4GW and comprises several combined units. Typical size of a NG plant is more like 500MW.

To put that into scale: a very large Manhattan skyscraper is in the 10-20MW range, so OpenAI is planning to use as much electricity as, well, all of Manhattan's skyscrapers and then some.

Since NG turbines are at best 60% efficient, the plant itself will generate ~6 GW worth of waste heat (remember: combined cycle, so they've already extracted as much heat as they can for power.)

10GW of heat is the same amount of energy as the amount of heat from solar radiation hitting roughly 10 square miles of the earth's surface.

It's also the difference between evaporative coolers which don't need as high static pressure, and dry coolers which need to force air through more dense air-liquid heat exchangers and also have to move more air.

Where people have pushed back on water consumption, rates have been raised (water deparments are increasingly going to nonlinear billing scales which charge people more per unit when they use more) or water just isn't available - datacenter operators have had to switch to "dry" cooling where coolant or refrigerant passes through a giant radiator.

Much less effective than evaporation. So you need to move a lot more air, and it also has to be done through a radiator, which probably has higher static pressure than an evaporative cooling tower.

Datacenters are fine, its gas turbines making the noise.

Whats crazy tho is people repeating this as if its true of all datacenters.

Whats even crazier is fringe australian politicians WHO LIVE NEAR DATA CENTERS importing this and claiming all datacenters in australia are noisy (because some terminally online seps were complaining about it) without so much as going down to their local and testing the hypothesis.

Over time, improvements have been made in compute density, because more compute density means more money.

Higher compute density means higher thermal density, which means more powerful cooling is needed.

Server cooling solutions follow a management triple constraint: cheap, effective, quiet, pick up to 2.

Because loudness does not incur additional costs (due to negative externalities), "quiet" is the point of the triangle which gets most often sacrificed.