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Comment by petesergeant | Hacker News Reader

I live in a desert where we have district cooling (and no shortage of sand or solar power), instead of district heating. Wonder if they can pull off the same trick.

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Well you can't really do -600C sand (or anything), so the benefits of sand VS water largely diminished. "just" freezing water already gives you around 300C equivalent of sand (if my napkin is correct).

Also the point of this plant is to exploit the counter-correlation of cheap electricity and cold. Usually there is a bigger correlation between cheap electricity and heat.

> you can't really do -600C sand (or anything)

You can if you stagger AC/HP or even peltier elements.

You misunderstood-- temperature is physically limited to -273°C, this is not an engineering problem. You have a smaller usable temperature range in a "cold storage" than with heat from fundamental physics alone.

Damn you got me there!

You can use heat to create cool by using absorption materials. It's of course way more complicated than with heat. But anyway with that, stored heat in sand could be used to create district cooling.

Cooling needs tend to correlate with the availability of solar energy. While heating especially far north does not so much.

In theory, yeah, cooling the sand would work, and it wouldn't freeze / expand. You'd need to use a coolant that doesn't freeze though, and of course keep any liquid out of it.

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