Finland creates "sand battery" in soapstone for storing thermal energy from renewable sources

[thewayne]

This is really cool.

In the town of Pornainen, they've built a 13 meter tall battery of "low-grade" sand that they warm-up to 450 degrees C - that 842 degrees F! - and it can hold that temperatures for weeks if not months, then they can use the hot air from it to heat the town's local heating network!

I think that's a pretty awesome use. They're using excess energy generated by renewable sources - free energy - to heat up the sand, then piping it around town. The former method to warm up the town was a woodchip furnace plant, clearly they're drastically cutting their CO2 footprint with this. And by using low-grade sand, their costs are pretty low.

But let's talk about sand for a minute. Businesses are literally dredging up ocean floors for sand to make more concrete. And you can't recover it from broken-up concrete when buildings are demolished. Now, to use sand to make a thermal battery I think is a worthwhile endeavor. I just wish they'd work out better ways to repurpose and recycle existing demolished concrete.

https://www.the-independent.com/tech/sand-battery-renewable-energy-finland-b2818348.html

https://hardware.slashdot.org/story/25/09/06/027211/a-very-finnish-thing-huge-sand-battery-starts-storing-wind-energy-in-soapstone

Comments

[bibliofile]

oooOOOOoooohh

Back in the '70s, a local ecology center built solar panels* and filled a storeroom with rocks to retain the heat. I never asked how well it worked, but it's the same idea innit.

* With wood and corrugated roofing. Got brown & black enamel paint all over my new painter's paints; made my mom mad.

[armiphlage]

Oooh, I remember those, like Trombe wall thermal storage! If I remember, the problem with them was that designers tried to rely on natural convection to distribute the heat. That doesn't work very well as the rocks come closer to room temperature, so you don't get all the stored energy out to where people need it. If you add a little fan, they work much better.