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Posted: Thu Mar 04, 2010 12:32 am
by Aero
Actually, you could just explode it then pour water in and use the steam until you need another explosion. Something like home made geothermal.

Posted: Thu Mar 04, 2010 1:13 am
by MSimon
Aero wrote:Actually, you could just explode it then pour water in and use the steam until you need another explosion. Something like home made geothermal.
I'd really like to see the primary vs secondary loop isolation on that one.

Posted: Thu Mar 04, 2010 1:25 am
by Aero
MSimon wrote:
Aero wrote:Actually, you could just explode it then pour water in and use the steam until you need another explosion. Something like home made geothermal.
I'd really like to see the primary vs secondary loop isolation on that one.
Don't worry about radiation, just drop your turbo generator most of the way down the hole and run it there. If it breaks, drop it the rest of the way and drop in a new one.

Posted: Thu Mar 04, 2010 4:33 am
by Helius
MSimon wrote:
Aero wrote:Actually, you could just explode it then pour water in and use the steam until you need another explosion. Something like home made geothermal.
I'd really like to see the primary vs secondary loop isolation on that one.
I heard that an M80 a little tough on the plumbing....

Posted: Thu Mar 04, 2010 4:46 am
by Helius
MSimon wrote:
NIF is going to surprise many folks as well: from what I gather, it is very likely get a pretty good Q sometime this year, and that may change a lot of perception about it.
Fusion bombs get pretty high Q. It does not make them a viable source of civilizational energy.
For me it isn't that an NIF like facility will ever become a viable power station, it is that it is a rapid development environment for inertial confinement (among other things). It *will* increase understanding rapidly.

To start, there will be gold hohlraum, but we don't know if one is required in every configuration. We also don't know if all 192 beamlines at full power will always be required.

Posted: Thu Mar 04, 2010 9:05 am
by Art Carlson
Aero wrote:
MSimon wrote:
Aero wrote:Actually, you could just explode it then pour water in and use the steam until you need another explosion. Something like home made geothermal.
I'd really like to see the primary vs secondary loop isolation on that one.
Don't worry about radiation, just drop your turbo generator most of the way down the hole and run it there. If it breaks, drop it the rest of the way and drop in a new one.
Where's the low temperature side of the loop?

Posted: Thu Mar 04, 2010 2:35 pm
by Aero
Art Carlson wrote:
Aero wrote:
MSimon wrote:I'd really like to see the primary vs secondary loop isolation on that one.
Don't worry about radiation, just drop your turbo generator most of the way down the hole and run it there. If it breaks, drop it the rest of the way and drop in a new one.
Where's the low temperature side of the loop?
Are you guys taking this idea seriously? Well, I guess it is a slow news era. I was more worried about ground water contamination myself. Heat sink? I guess you'd need to use conductive heating into the cooler rock at the elevation of the generator. That would make it more complicated though, especially when you had to replace the turbo generator.

Posted: Thu Mar 04, 2010 3:58 pm
by MSimon
Giorgio seems to think you could use something like the device described in his links to make something like that work.

viewtopic.php?p=35775#35775

I'm not convinced.

Posted: Thu Mar 04, 2010 5:17 pm
by StevePoling
Aero wrote:
Art Carlson wrote:
Aero wrote:Don't worry about radiation, just drop your turbo generator most of the way down the hole and run it there. If it breaks, drop it the rest of the way and drop in a new one.
Where's the low temperature side of the loop?
Are you guys taking this idea seriously? Well, I guess it is a slow news era. I was more worried about ground water contamination myself. Heat sink? I guess you'd need to use conductive heating into the cooler rock at the elevation of the generator. That would make it more complicated though, especially when you had to replace the turbo generator.
I take the blame. I posed to myself a gedanken experiment, "how could I use an h-bomb to generate usable energy?" It's a lot more interesting than nuking a path across Nicaragua to create a sea-level (no locks) canal. I must have read too many "atoms for peace" articles when I was a kid.

Posted: Thu Mar 04, 2010 5:47 pm
by Aero
I don't know. Devices that operate using the Seebeck effect, the Peltier effect, and the Thomson effect are very interesting to study but so far the efficiencies are too low. The theoretical basis seems to be in place so it wouldn't be surprising if usefully efficient generating devices are developed near term.

It should be possible to develop a thought experiment that shows a perpetual motion machine if such devices exceed Carnot efficiency. Given a 100% efficient Carnot machine and a 100% efficient thermoelectric device, then the Carnot machine generates electricity to drive the thermoelectric device which heats the hot side of the Carnot machine. If the thermoelectric device creates more heat than the Carnot machine uses you have perpetual motion. I have the feeling that is unlikely.

Of course maybe I'm missing the point.

Posted: Thu Mar 04, 2010 6:27 pm
by MSimon
Aero wrote:It should be possible to develop a thought experiment that shows a perpetual motion machine if such devices exceed Carnot efficiency. Given a 100% efficient Carnot machine and a 100% efficient thermoelectric device, then the Carnot machine generates electricity to drive the thermoelectric device which heats the hot side of the Carnot machine. If the thermoelectric device creates more heat than the Carnot machine uses you have perpetual motion. I have the feeling that is unlikely.

Of course maybe I'm missing the point.
That was my take. Giorgio seems to think I'm missing the point. What I'm wondering is how the paper got past peer review. Not on the actual science but the projections that in the future such a mechanism can beat Carnot.

Posted: Thu Mar 04, 2010 6:41 pm
by chrismb
Look up "Project Gnome".

Posted: Thu Mar 04, 2010 10:04 pm
by Giorgio
Aero wrote:I don't know. Devices that operate using the Seebeck effect, the Peltier effect, and the Thomson effect are very interesting to study but so far the efficiencies are too low. The theoretical basis seems to be in place so it wouldn't be surprising if usefully efficient generating devices are developed near term.

It should be possible to develop a thought experiment that shows a perpetual motion machine if such devices exceed Carnot efficiency. Given a 100% efficient Carnot machine and a 100% efficient thermoelectric device, then the Carnot machine generates electricity to drive the thermoelectric device which heats the hot side of the Carnot machine. If the thermoelectric device creates more heat than the Carnot machine uses you have perpetual motion. I have the feeling that is unlikely.

Of course maybe I'm missing the point.

Obviously if you have a system that transform anything you put inside in something else with 100% efficient you have a closed loop and hence perpetual motion.
Anyhow this is not our case.


The 100% efficient Carnot machine that you refer to, can have two meaning:
1) The value of the Carnot-cycle efficiency is 100%, but this is impossible to get from the the definition itself of the Carnot-efficiency formula:
n= 1-(Tc/Th), but by definition is always Tc/Th<1 so it can never be n>=1 .

2) The considered machine has a carnot efficiency of 100% in respect to its working temperatures.
Given T1 and T2, and a Carnot-cycle efficiency of 60%, than an 100% efficient Carnot machine will give back only 60 units out of 100 inserted.
Even if you beat the Carnot efficiency with a thermochemical machine (or other systems) and bring the "global efficiency" of the system to 90% you are still losing 10 units for each cycle, meaning your system will sooner or later reach zero available units.

You are not getting perpetual motion, but you are getting more out than the Carnot-cycle efficiency.

Even if I had to misuse some terms to make the above the most clear possible, I hope it was clear enough to remove the various doubts.

Posted: Thu Mar 04, 2010 10:39 pm
by Aero
Is this the kind of application you are referring to?

http://gm-volt.com/forum/showthread.php?t=1258

Posted: Fri Mar 05, 2010 12:18 am
by John Gallagher
A 1 meg warhead will yield 4.2 E15 joules. At 40% conversion you get a gigawatt for 20 days. Bet this is the most expensive power you could come up with.