Materials science question for APS...

[Fly320s]

But won't more energy be used to make the battery molten hot than what the battery puts out? 

[Nick1911]

You can maintain a high thermal gradient with fairly minimal input with appropriate insulation.

Consider something the size of a 55 gallon barrel.  32ft² of surface area. 

Ambient temp, 70F.  Battery temp, 600F.  Thermal difference of 530F

Assuming R11 insulation:

U value = (1/11) = 0.0909 BTU/(hr °F ft²)  *  32 ft² * 530 °F = 1541 BTU/hr  * (1 watt / 3.414 BTU) = 451 Watts/hour

Assuming R-50 insulation:

U value = (1/11) = 0.0200 BTU/(hr °F ft²)  *  32 ft² * 530 °F = 339 BTU/hr  * (1 watt / 3.414 BTU) = 99 Watts/hour

In the context of a battery that large, it's not bad.

That said, this is a function square-cube law - it won't scale down well, but it will scale up even better.

[KD5NRH]

In the context of a battery that large, it's not bad.

And easily provided by a simple gas burner.  Storing potential heat (and making it into actual heat) is easier than getting electricity to stay in a can.

[Nick1911]

And easily provided by a simple gas burner.  Storing potential heat (and making it into actual heat) is easier than getting electricity to stay in a can.

Eh, I wouldn't.  You'll need heat exchange between an open flame and the battery, which is by definition uninsulated space.

Plus, I imagine there would be pushback from the green culture surrounding products like this to using gas burners.

No, I think it makes far more sense to use electric resistance heating for this.

[kgbsquirrel]

You can maintain a high thermal gradient with fairly minimal input with appropriate insulation.

Consider something the size of a 55 gallon barrel.  32ft² of surface area. 

Ambient temp, 70F.  Battery temp, 600F.  Thermal difference of 530F

Assuming R11 insulation:

U value = (1/11) = 0.0909 BTU/(hr °F ft²)  *  32 ft² * 530 °F = 1541 BTU/hr  * (1 watt / 3.414 BTU) = 451 Watts/hour

Assuming R-50 insulation:

U value = (1/11) = 0.0200 BTU/(hr °F ft²)  *  32 ft² * 530 °F = 339 BTU/hr  * (1 watt / 3.414 BTU) = 99 Watts/hour

In the context of a battery that large, it's not bad.

That said, this is a function square-cube law - it won't scale down well, but it will scale up even better.

Ding ding ding!!!

I'm basically putting this sucker in a glorified dewar. God it's good to have easy access to vacuum pumps and stuff... 

[kgbsquirrel]

To clarify, the molten battery will be chillin' in a fused quartz vessel, which itself will be housed inside a cobalt steel pressure vessel which is then itself housed inside a stainless steel vacuum chamber. Under vacuum.

In other news I think I'm going to source the glass locally. I can't wait to see the look of terror in their eyes when I utter the words "fused quartz". 

[HankB]

. . . I can't wait to see the look of terror in their eyes when I utter the words "fused quartz". 

Bet it won't match the look of terror we got from our safety people when were were loading optical fiber with H2 in a device we called a hydrogen bomb.

And then we decided to try it with deuterium . . . 

[kgbsquirrel]

Bet it won't match the look of terror we got from our safety people when were were loading optical fiber with H2 in a device we called a hydrogen bomb.

And then we decided to try it with deuterium . . . 

What, you think you're special or something over there Mr. Q? 

[KD5NRH]

I'm basically putting this sucker in a glorified dewar. God it's good to have easy access to vacuum pumps and stuff...

Oooh...Democrats in molten salt in a hard vacuum...this just keeps getting better.

You are testing stupidity for viability as the magic element in this, right?

[kgbsquirrel]

Oooh...Democrats in molten salt in a hard vacuum...this just keeps getting better.

You are testing stupidity for viability as the magic element in this, right?

It seems worth a try. I'm thinking pureed, boiled down, foamed, injected into the interstitial space and freeze dried in place. Do you think the Stupid(tm) will be concentrated enough?

[KD5NRH]

It seems worth a try. I'm thinking pureed, boiled down, foamed, injected into the interstitial space and freeze dried in place. Do you think the Stupid(tm) will be concentrated enough?

Go for the Sanders crowd.  That's about as dense as it gets.