3 ms·
it seems the primary benefit for sand over water, is a 1:10 operating temp vs. 5:1 specific heat. So it depends on whether the added complexity of working with
by leecarraher 3y ago
it seems the primary benefit for sand over water, is a 1:10 operating temp vs. 5:1 specific heat. So it depends on whether the added complexity of working with a hotter, solid is worth not having to build a facility that is 2x bigger. Are there other benefits I'm missing, or is this concrete block gravity storage vs pumped water storage, all over again?
- pfdietz 3y agoIf the goal is conversion back to electrical energy, the high temperature is a huge advantage.
- nick238 3y agoComparing water's 4.18 kJ/kg-K * ~75 K (25 °C -> 100 °C) to the sand's 1.1 kJ/kg-K * 900 K? I think you can (or it's easier) get more useful work out of a lesser amount of hotter stuff, even if the thermal energy or total heat is the same. Unsure of that, I don't know what the specific principle is. I'd vaguely gesture at the 2nd law of thermo as if I poured a cup of boiling water into a pot of room-temperature water, the total heat leaving the pot would wind up being the same as the heat leaving the cup, but less useful?
- NegativeK 3y agoSand doesn't leak down or up (via evaporation) nearly as much. It's also far less of a precious resource and non-corrosive, compared to the most common version of water.