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A shipping container is filled with sand and painted dark black, so that the sand within can be heated. During the day, solar heat will be deposited into the sand for thermal storage. During the night, the heat can be pulled out from storage via a heat pump. This can be used to heat a house and provide
hot water.
Thermal sand batteries are already a thing.
https://hackaday.co...rself-sand-battery/
[pertinax, Oct 30 2024]
Domestic Wax Phase Change
Eutectic_20water_20heater
[bs0u0155, Oct 31 2024]
[link]
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I'm not sure how this is different from, or better than, existing sand-based heat batteries. |
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Sand is stupid in this context. A Shipping container is useful because its a standardized unit of the movement of physical things. They have a weight limit of ~65,000lb or 30 metric tons and a volume of ~67 cubic meters. Filling it with sand would put it ~3x over its max weight limit. |
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Then there's the thermal performance of sand ~ 800J/kg/C vs water at 4200J/kg/C. So per ton, sand is ~ 8 fold worse than water at thermal storage. |
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Much better to go with a phase change material, water/ice are outstanding at this at 334,000J/kg/C but with an inconvenient temperature. Sodium sulfate in water can be around 200,000J/kg/C at ~40C or so. That's 250 fold better than sand. |
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So you can replace your unmovable shipping container full of sand with a garbage can of sodium sulfate/water. You could even get one of those dollies so that you could wheel the thing where you needed. |
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Sodium sulfate is decidedly less plentiful than sand. At least so the inhabitants of the Sahara tell me. I'd pick something less expensive. |
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@bs0u0155: Google Gemini suggests Paraffins are the best candidate materials for a home-scale thermal storage battery, and that's because they offer good latent heat of phase change. I was suggesting sand because it's cheap. What ultimately matters is J/dollar more than J/kg. Per-unit-mass isn't that important, when it's a stationary power source. |
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//Google Gemini suggests Paraffins are the best candidate materials for a home-scale thermal storage battery,// |
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There are even smarter applications [link] if you put in more effort than the average AI. |
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