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Comment by dgoldstein0 | Hacker News Reader

The climate requirements to run at this hotter temperature still probably means it'll require more active cooling in the desert during daytime /summers. Assuming we're talking about hotter desert environments like US southwest. That might make your proposal not as economical.

Imo we should just solve the problems with data centers being near cities. Manage/regulate the noise and any waste (heat included, it shouldn't drastically impact the neighbors) and make them pay for any utility capacity/reliability upgrades needed. If this article is right and water usage can be nearly eliminated then it seems like the rest should be solvable? Especially if we can take the extra heat and use it for local power or heating needs.

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You might (but probably not) be able to do district heating with this, but electricity generation is not going to be efficient. Heat is a very low grade form of energy, and you need a large differential to drive a turbine efficiently.

If you cycle between 45 C and 55 C water temperature (as mentioned by the press release), you are only getting a 10 C delta. That isn't even enough for district heating, probably not even with heat pumps.

Now if you have something like a steel foundry, that have much hotter cooling water, you can absolutely use the heat for district heating, but even then it usually isn't enough for cost effective electricity generation. Even when it is waste heat, as the equipment to handle it still costs money and requires maintenance.

> If you cycle between 45 C and 55 C water temperature (as mentioned by the press release), you are only getting a 10 C delta.

You are calculating the wrong delta T. To heat a space, you need your working fluid to be warmer that the space you’re heating by an appropriate amount.

55°C is certainly on the cool side to heat a building, but it’s entirely workable with a high-area, highish-thermal-conductivity system. Here’s an actual chart:

https://www.warmboard.com/wp-content/uploads/2022/04/WaterTe...

You don’t actually want an absurdly warm floor.

Even for buildings that need warmer fluid, water at 45-55°C is a fantastic source for a heat pump.

55 C might be enough to heat buildings but it's right on the edge where domestic hot water needs to be to kill Legionella. So traditional DH systems need to run hotter.

There low-temp/cold DH systems out there that rely on heatpumps in the buildings to extract the heat. Less losses in the network and you can even use them for cooling, but needs heat pumps everywhere.

In comparison, a traditional heat exhanger is pretty simple technology; just a hunk of metal with a valve.

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