| ▲ | pfdietz 6 hours ago |
| The temperature swing can be much greater than 100 C. Heat can be extracted as a wave passing through the store, then heat added back by reversing the flow. It would operate like a counterflow heat exchanger. View another way: if we hook several piles in series, then lukewarm air from a first mostly discharged pile can be directed into later piles for more heating. In the continuous limit this is the concept I described above. |
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| ▲ | cyberax 5 hours ago | parent [-] |
| > The temperature swing can be much greater than 100 C. No, because your steam will be at a lower temperature as you draw down the heat, bringing down efficiency. |
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| ▲ | adgjlsfhk1 4 hours ago | parent | next [-] | | Realistic designs for this can achieve 450C delta t. Your energy store can store at ~1000C (slightly below rock melting point), and run steam turbines with a hot side of 600C and a cool side of 150C. Over the season, your sand drops from ~1000 to ~600 (which is fine since your power needs drop in the spring) | | |
| ▲ | cyberax 34 minutes ago | parent [-] | | Sorry, but 1000C is wildly unrealistic. There are no bulk materials that can be used to construct heat exchangers for this kind of environment. 600C is already a stretch. At 1000C steel will react with _water_. To be clear, I'm not talking about cooling a small crucible but a structure that is at least 20 meters in size. |
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| ▲ | pfdietz 4 hours ago | parent | prev [-] | | That is wrong, and I already explained why. |
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