scaleablity of a reactor?

[ohiovr]

Getting break even and beyond is of course the primary concern but is it possible to scale the power of these reactors? The polywell people think they can get a gigawatt out of a reactor 10 meters across. Lots of little reactors is fine of course but could something larger be made? I’m looking for electrical generators for space applications. Focus fusion is already a plus because it doesn’t use thermal effects for power generation and thermal management is not so great in space with no cold air or water to sync to. Any chance for gigawatt reactors?

[DerekShannon]

Yes, it’s called two hundred 5MW generators!

Seriously, if Discovery finally launches, the ISS will get up to just over 100kW. Don’t be so greedy! ;-D

What do you want to do with the full GW, anyhow? After all, I don’t know if we can trust you not to subdue the globe with an orbital laser platform…..

[ohiovr]

I was thinking about high thrust and high specific impulse electrical thrusters.

[Aeronaut]

About the cooling, we’ve been discussing this in the https://focusfusion.org/index.php/forums/viewthread/283/

In a nutshell, FF runs 50% efficient, which means that the 5MW electrical output is roughly matched by another 5MW of thermal energy to find a use for. This means that for some applications it could be pitched as a 9 or 10MW reactor.

[Brian H]

Aeronaut wrote: About the cooling, we’ve been discussing this in the https://focusfusion.org/index.php/forums/viewthread/283/

In a nutshell, FF runs 50% efficient, which means that the 5MW electrical output is roughly matched by another 5MW of thermal energy to find a use for. This means that for some applications it could be pitched as a 9 or 10MW reactor.

So there is a need for efficient thermal conversion here. Interesting …

[Aeronaut]

Brian H wrote:

About the cooling, we’ve been discussing this in the https://focusfusion.org/index.php/forums/viewthread/283/

In a nutshell, FF runs 50% efficient, which means that the 5MW electrical output is roughly matched by another 5MW of thermal energy to find a use for. This means that for some applications it could be pitched as a 9 or 10MW reactor.

So there is a need for efficient thermal conversion here. Interesting …

I’ve read the patent and dissected the Google video since the above post. Eric is actually predicting 42% efficiency in the Google Talk video.

The best plan outline that I can see right away is to pitch it as an energy source that will generate 4.2MW of electricity and 5.8MW of heat (~20MBTU)/hr at temperatures of around 400 degrees F for building and low-temperature process heating, to minimize the thermal pollution.

In short, the ideal prospect owns a large pre-existing heatsink like a factory.

[Brian H]

Aeronaut wrote:

About the cooling, we’ve been discussing this in the https://focusfusion.org/index.php/forums/viewthread/283/

In a nutshell, FF runs 50% efficient, which means that the 5MW electrical output is roughly matched by another 5MW of thermal energy to find a use for. This means that for some applications it could be pitched as a 9 or 10MW reactor.

So there is a need for efficient thermal conversion here. Interesting …

I’ve read the patent and dissected the Google video since the above post. Eric is actually predicting 42% efficiency in the Google Talk video.

The best plan outline that I can see right away is to pitch it as an energy source that will generate 4.2MW of electricity and 5.8MW of heat (~20MBTU)/hr at temperatures of around 400 degrees F for building and low-temperature process heating, to minimize the thermal pollution.

In short, the ideal prospect owns a large pre-existing heatsink like a factory.

Yes. Many of us have concluded that the cost-benefit of any thermal conversion/generation process would so far exceed the cost of just making more FF generators to create the same output that only easy passive heat uses would be worthwhile.

[Aeronaut]

This decade and the next few are going to be the golden age for Consulting Sales Engineers with a variety of ion and x-ray converters, heat exchangers, electrical components, etc.

[Brian H]

Aeronaut wrote: This decade and the next few are going to be the golden age for Consulting Sales Engineers with a variety of ion and x-ray converters, heat exchangers, electrical components, etc.

Yes, I keep thinking about the observation that a heat pump can be ~300% efficient, in the sense that it can put out much more thermal energy taken from the environment (or, I assume, from hot air coming off an FF generator) than it takes to run its compressors etc.

[Aeronaut]

300% is hot air, lol.

My understanding of a heat pump is that it moves latent heat (vs sensible heat) from one side of the wall to the other. I got one, and there’s still a compressor outdoors inside the condenser.

[Brian H]

Aeronaut wrote: 300% is hot air, lol.

My understanding of a heat pump is that it moves latent heat (vs sensible heat) from one side of the wall to the other. I got one, and there’s still a compressor outdoors inside the condenser.

That’s the point. The compressor’s energy use translated into straight thermal energy is about 1/3 the heat it actually moves (in or out). So using 1 kwh to heat-pump heat into your home gets you 3X the heat that an electric heating element/radiator could supply. :cheese:
“When used for heating a building on a mild day, a typical air-source heat pump has a COP [Coefficient Of Performance] of 3 – 4, whereas a typical electric resistance heater has a COP of 1.0. That is, one joule of electrical energy will cause a resistance heater to produce one joule of useful heat, while under ideal conditions, one joule of electrical energy can cause a heat pump to move much more than one joule of heat from a cooler place to a warmer place.”(Wiki)

[Aeronaut]

Very clear explanation. It was late and I thought 300% was something for nothing [grin].

[JimmyT]

This whole discussion provides a very clear illustration of low entropy energy (electricty) being downgraded and in the process producing more enthalpy. It’s really implicit in Carnot’s law if you look at it right.

[JimmyT]

With regard to the scalability question:
It would probably be farsighted to try to fit one of these power units into a containerized cargo unit right at the beginning of the design phase. They might need outriggers to contain shielding water (mainly for neutrons.) I’ve seen many references in the forums to these units being “about the size of semi trailers”. Well, maybe we should endevor to make them exactly the size of those modular trailers. They would sure be easy to transport that way.

[Aeronaut]

JimmyT wrote: With regard to the scalability question:
It would probably be farsighted to try to fit one of these power units into a containerized cargo unit right at the beginning of the design phase. They might need outriggers to contain shielding water (mainly for neutrons.) I’ve seen many references in the forums to these units being “about the size of semi trailers”. Well, maybe we should endevor to make them exactly the size of those modular trailers. They would sure be easy to transport that way.

That standardized form factor would be a huge plus for shipping FF around the world. But a meter of water in all directions is a lot of mass, volume, and steel that isn’t absolutely required, as thinner, lighter shielding materials might give us a torpedo-like form factor.

This in turn could possibly fit 4 or more reactors into the container, along with the control room.

[Author]

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