> Also, the temp is usually capped at 180F, so nowhere near what these guys are getting. I think that’s a good reason for them to not use water. _If_ you’re de

> Also, the temp is usually capped at 180F, so nowhere near what these guys are getting. I think that’s a good reason for them to not use water. _If_ you’re designing for 600°C, I would think using water is quite risky. I would also think sand at 600°C stores more energy per volume or mass than water at 180°F.