A map of the lower 48 US States with an overlay of various colorful bubbles indicating data center developments, whether proposed, contested, under construction, or operational. There are a lot of bubbles! Hawaii isn't pictured, but looks to have one project currently, but nothing in Alaska for now.

Who’s Building That Data Center?

One of the biggest “David versus Goliath” stories in tech right now is the towns beset by AI data center projects they may or may not have asked for. Powered By Who is tracking data center development in the US on this convenient map.

Currently, there are over 2,100 data centers being tracked by the project ranging from proposals to sites fully up-and-running. While you have to build bypasses data centers to keep the internet running (which we’re partial to here at Hackaday), there are certainly questions around the amount of power and water consumed by these sites, the emissions they’re sending into the surrounding community, and who exactly is reaping the benefits.

Whether you’re pro, against, or ambivalent about the proliferation of “AI” data centers, the map offers an engaging way to look at what projects are happening around the nation, especially when you start looking at clusters and how that interacts with the power generation and political makeup in a region. It’s particularly interesting how only three states account for roughly 70% of all the projects. Let us know if there’s a similar tracker in your area if you’re from one of the other parts of the globe!

Looking past the debate, there’s a lot of interesting engineering involved in keeping these data centers cool, although there are questions about where that heat ends up going. DC distribution inside the site, underwater data centers, and even putting them in space are some of the solutions for keeping the cooling loads tamed.

The Coolest Hat At The Hacker Camp

People in hotter parts of the world may permit themselves a grin at this, but Europeans have recently been suffering under an unseasonal June heatwave. Most of us have been cowering inside with our air conditioners, but not [Making Stuff With Mike]. He’s adapting a safety helmet with a Noctua fan for only slightly uncool on-the-go cooling.

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Building A Gifford-McMahon Cryocooler With 3D-Printed Parts

Although cryocoolers are capable of pretty impressive cooling, for many of them the underlying working principle is simple enough that you do not need any special skills or a big budget to make your own version. Take the Gifford-McMahon cryocooler for example, which works using nothing more than some kind of coolant gas and a piston in a cylinder that you can even 3D print, as demonstrated by [Hyperspace Pirate] in a recent video.

The lowest temperature reached across the two prototypes was only -84°C, but this was mostly due to some sub-optimal design choices, such as the use of regular air and a clear acrylic tube to get a good glimpse at the inner workings. The trickiest part of this type of cryocooler is probably that you need to move the piston containing the regenerator between both ends of the cylinder to get a cool and a hot side.

That particular problem was solved by using magnets to move the piston externally, which worked beautifully until the problem of using regular compressed air from the shop compressor caused massive ice formation that jammed up the piston. Obviously this was not an unexpected issue, and for the next step the coolant gas will be replaced by helium, as making that gas freeze up requires quite a bit more effort.

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The Heat Island Effect Is Warming Up The AI Data Center Controversy

There’s been a lot of virtual ink spilled in environmental circles about the cooling water requirements of data centers, but less consideration of what happens with all the heat coming out of these buildings. Naturally, it’s going to warm the surrounding environment, but how much? Around 2 C (3.6 F) on average, and potentially much more than that, according to a recent study on the data heat island effect.

It’s common sense, of course: heat removed from the data center doesn’t go away. That heat might go into a body of water if one is available, but otherwise it’s out into the atmosphere to warm up everybody else’s day. In some places — like a Canadian winter — that might not be so bad. In others, where climate change and urban heat islands are cranking up the summertime temperatures, it very much could be. Especially if you’re in the worst-case scenario micro-climate described by the paper, which saw a predicted increase of 9.1 C (16 F).

Now, these results are theoretical and need to be ground-truthed, but anyone who has huddled next to the air-exchange unit of a large building for warmth knows there’s something to them. Unfortunately there don’t seem to be before-and-after measurements available for existing data-centers — AI or otherwise — to show exactly what their heat output is doing in the real world, but the urban heat island effect from all the dark asphalt in our cities is well known. Cooling paint and green roofs can help with that, but they won’t do much for the megawatts being pumped out to keep your cousin’s AI girlfriend online.

Some would argue that all this heat wouldn’t be a problem if we could launch the data centers outside the environment — just have a care the front doesn’t fall off.


Image of data center cooling by Анна from Pixabay

How Water Vapor Makes Smartphones Faster

Once upon a time, home computers were low-powered enough that they barely needed any cooling at all. An Amiga 500 didn’t even have a heatsink on the CPU, while the early Macintosh got by with a single teeny little fan.

Modern smartphones are far more powerful than these ancient machines, packed with multi-core processors running at speeds of many gigahertz. Even still, they’ve generally been able to get by without any active cooling devices. However, as manufacturers continue to push the envelope of performance, they’ve had to scramble for ways to suck heat out of these handheld computers. Vapor chamber cooling has risen as a solution to this problem, using simple physics to keep your handset humming along at maximum speed for longer.

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Hackaday Links: August 17, 2025

We’ve studiously avoided any mention of our latest interstellar visitor, 3I/Atlas, on these pages, mainly because of all the hoopla in the popular press about how Avi Loeb thinks it’s aliens, because of course he does. And we’re not saying it’s aliens either, mainly because we’d never be lucky enough to be alive during an actual alien invasion — life just hasn’t historically been that kind to us. So chances are overwhelming that 3I/Atlas is just a comet, but man, it’s doing its level best to look like it’s not, which means it’s time to brave the slings and arrows and wade into this subject.

The number of oddities surrounding 3I/Atlas just keeps growing, from its weird Sun-directed particle stream to its extreme speed, not to mention a trajectory through the solar system that puts it just a fraction of an astronomical unit from two of the three planets within the “Goldilocks Zone” of our star — ignore the fact that at an estimated seven billion years old, 3I/Atlas likely would have started its interstellar journey well before our solar system had even started forming. Still, it’s the trajectory that intrigues us, especially the fact that it’s coming in at a very shallow along to the ecliptic, and seems like it will cross that imaginary plane almost exactly when it makes its closest approach to the Sun on October 29, which just coincidentally happens to be at the very moment Earth is exactly on the opposite side of our star. We’ll be as far as possible from the action on that date, with the comet conveniently lost in the glare of the Sun. Yes, there’s talk of re-tasking some of our spacecraft around Mars or in the Jovian system to take a peek when 3I/Atlas passes through their neighborhoods, but those are complicated affairs that show no sign of bearing fruit in the short time left before the comet heads back out into the Deep Dark. Too bad; we’d really love an up-close and personal look at this thing.

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ice forming on surface with plus and minus pole

The Coolest Batteries You’ve Never Heard Of

Imagine cooling your building with the same principle that kept Victorian-era icehouses stocked with lake-frozen blocks, but in modern form. That’s the idea behind ice batteries, a clever energy storage hack that’s been quietly slashing cooling costs across commercial buildings. The invention works by freezing water when energy is cheap, and using that stored cold later, they turn major power hogs (air conditioning, we’re looking at you) into more efficient, cost-effective systems.

Pioneers like Nostromo Energy and Ice Energy are refining the tech. Nostromo’s IceBrick modules pack 25 kWh of cooling capacity each, install on rooftops, and cost around $250 per kWh—about half the price of lithium-ion storage. Ice Energy’s Ice Bear 40 integrates with HVAC systems, shifting up to 95% of peak cooling demand to off-peak hours. And for homes, the Ice Bear 20 replaces traditional AC units while doubling as a thermal battery.

Unlike lithium-ion, ice batteries don’t degrade chemically – their water is endlessly reusable. Combining the technology with this hack, it’s even possible in environments where water is scarce. But the trade-off? They only store cooling energy. No frozen kilowatts for your lightbulbs, just an efficient way to handle the biggest energy drain in most buildings.

Could ice batteries help decentralize energy storage? They’re already proving their worth in high-demand areas like California and Texas. Read the full report here and let us know your thoughts in the comments.

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