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World's Largest Sand Battery - YouTube Short
(www.youtube.com)
Brilliant idea.
Back when I was studying my group had a small project that was about sunstainable farming on Mars and one of the biggest challenge was the cold nights on Mars. We determined that heating up sand just right and surrounding growing-pods with said sand might work as a low energy cost solution to keep plants at a good temperature outside of living areas.
This didn't lead to much but was a great learning experience.