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Has Weber gone Ecofreak on Us? CoG Spoiler Alert!

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Has Weber gone Ecofreak on Us? CoG Spoiler Alert!
Post by namelessfly   » Mon Apr 14, 2014 11:19 am

namelessfly

I am just about finished with CoG. It is far better than ART or SoF.

However; some of the references and assumptions are absurd.

Take Chapter 35 where the cruise ship is sunk, . The authors use a couple who are suffering from seasickness as POV characters to describe events. Fine. Then they state that the latent energy of planetary Ocean impacted by winds dwarfs the energy output of a modern civilization.

The classic article THE ENERGY RESOURCES OF THE EARTH published in Scientific American lists the wind, wave and tidal energy of the Earth as about 400eex12 Watts. I have found no significant, credible dispute to this number.

If you have a planetary population of 10 Billion people, this is works out to only 40 kW per person which is within an order of magnitude of the US energy consumption rate.

Honorverse technology is far, far more energy intensive than modern technology. Example is a small, 2 million ton tramp freighter using fusion rockets to pull 20 gees.

That is 2eex9 Kg x 200 N/Kg = 4eex11 Newtons


The power of a rocket misgiven by P = 1/2 x T x Ve = 1/2 x 4eex12 x 3eex7 m/s = 6eex19 Watts.

The latent energy of your planetary ocean doesn't even come close to the power output of Honorverse fusion technology.

Equally absurd are the comments about high population density cities being desirable because they are more energy efficient with lower ecological impact than suburbs and the inhabitants being better educated. If you have aopulation of 10 billion living in suburbs at say 1,000 square meters per home and a typical occupancy rate of 4 people per dwelling unit, you get 4,000 people per square kilometer and need 2.5 million square kilometers which iscomparable to the State of Texas.

I would love to know if Weber and Flint considered waste heat from mega cities where aside from the main fusion reactors each building has itsown fusion reactor. Concentrate the population so severely and they will boil a river.
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Re: Has Weber gone Ecofreak on Us? CoG Spoiler Alert!
Post by kzt   » Mon Apr 14, 2014 1:43 pm

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There is a LOT of slapdash thinking in CoG.

For example, Honorverse fusion reactors have been clearly established to blow up real good when you damage them because reasons. So destroying the tower with a megaton range KE weapon would result in a gigaton range deeply buried underground explosion of the fusion reactor, which would produce a crater many km wide and probably kill 50% or more of the city population.

The idea that you might disconnect the vast heat exchanger needed to cool the fusion reactor in the basement never occurred to any of the people attacking the building because it never occurred to the authors that there would be one needed.

Plus you see wedge based ground weaponry used in multiple previous books, but not a single one was even mentioned here, much less used in an intelligent fashion.
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Re: Has Weber gone Ecofreak on Us? CoG Spoiler Alert!
Post by Potato   » Mon Apr 14, 2014 1:49 pm

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A warship's fusion plants might well explode quite spectacularly, given the energy levels a warship requires. A tower housing 10,000 civilians is unlikely to use even a single percent of that.
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Re: Has Weber gone Ecofreak on Us? CoG Spoiler Alert!
Post by aairfccha   » Mon Apr 14, 2014 1:52 pm

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Potato wrote:A warship's fusion plants might well explode quite spectacularly, given the energy levels a warship requires. A tower housing 10,000 civilians is unlikely to use even a single percent of that.
Not just power, in general you don't need maximum power density stationary on the ground, which is another factor in explosiveness.
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Re: Has Weber gone Ecofreak on Us? CoG Spoiler Alert!
Post by Borealis   » Mon Apr 14, 2014 2:08 pm

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aairfccha wrote:
Potato wrote:A warship's fusion plants might well explode quite spectacularly, given the energy levels a warship requires. A tower housing 10,000 civilians is unlikely to use even a single percent of that.
Not just power, in general you don't need maximum power density stationary on the ground, which is another factor in explosiveness.


Also, a warships reactor would be size/mass limited. Basically you'd want to get the most power out of the smallest package. I'd imagine you'd run a ship reactor at a much higher 'pressure'. Take in the need for plasma conduits to run weapons systems and your alpha/beta nodes and containment becomes a much trickier proposition.

Compare that to the needs of powering a residential tower. RFC doesn't provide enough detail to determine just how you get power out of a reactor, but I imagine it is still some form of heat exchange system ultimately running a generator of some kind. I doubt a very large reactor would be necessary to supply the requisite thermal energy, especially considering the efficiency implied for power transmission. Something that small (and directly below 10,000 people) would undoubtedly be able to have some very impressive safety features.
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Re: Has Weber gone Ecofreak on Us? CoG Spoiler Alert!
Post by JohnRoth   » Mon Apr 14, 2014 6:28 pm

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kzt wrote:There is a LOT of slapdash thinking in CoG.

For example, Honorverse fusion reactors have been clearly established to blow up real good when you damage them because reasons. So destroying the tower with a megaton range KE weapon would result in a gigaton range deeply buried underground explosion of the fusion reactor, which would produce a crater many km wide and probably kill 50% or more of the city population.

The idea that you might disconnect the vast heat exchanger needed to cool the fusion reactor in the basement never occurred to any of the people attacking the building because it never occurred to the authors that there would be one needed.

Plus you see wedge based ground weaponry used in multiple previous books, but not a single one was even mentioned here, much less used in an intelligent fashion.


There are two types of fusion reactors. The ones a warship carries are size-limited on the bottom end: the smallest possible ones can power a normal destroyer --- they're overkill for a frigate or dispatch boat. The ones used in smaller ships like pinnaces work on a different principle, and aren't all that efficient if you try to scale them up, which is why frigates and dispatch boats use the same fusion plants as destroyers, and why LACs are caught in a bind.

I presume they've got a much more effective method of fusion to electricity conversion than heat transfer running steam turbines. It's probably related to the heat scavenging technology that keeps a starship from evaporating into a ball of plasma from the amount of waste heat.
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Re: Has Weber gone Ecofreak on Us? CoG Spoiler Alert!
Post by Randomiser   » Mon Apr 14, 2014 6:48 pm

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I don't think it has been established that "Honorverse fusion reactors blow up real good when you damage them". All that has been established is that a warship's reactors contain enough plasma tbat the sudden overpressure caused by it's expansion and the vaporisation of the area around the reactor is sufficient to shred the said warship into little pieces if containment fails. That is nothing like a Gigaton range explosion.

Also we know nothing about the thermal efficiency of an Honorverse fusion reactor in the civilian city power application. Maybe they have ways to turn heat directly into electricity at high efficiency, who knows? Can you set up a gravity gradient sufficient to slow the particles which hit it and extract the energy somehow? I seem to have missed the "applications of gravitics" course at school. By the way, what did you say the typical output of one of these residential tower reactors was?


A certain amount of low grade residual heat will be very useful for heating systems and hot water in the tower and surrounding industrial complexes, of course.
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Re: Has Weber gone Ecofreak on Us? CoG Spoiler Alert!
Post by kzt   » Mon Apr 14, 2014 7:30 pm

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Randomiser wrote:All that has been established is that a warship's reactors contain enough plasma tbat the sudden overpressure caused by it's expansion and the vaporisation of the area around the reactor is sufficient to shred the said warship into little pieces if containment fails. That is nothing like a Gigaton range explosion.

Perhaps you should reread chapter 46 of Echos Of Honor?

How much energy do you need to vaporize a half meter of Honorverse battle cruiser armor at 600 km from an omnidirectional explosion?

Well, we don't really know the characteristics of the armor, but I think it's safe to assume it's at least equal to iron in resisting damage.

A section of iron 1 meter square and .5 meters deep weights about 4 tons. The heat of vaporization of iron is about 6 megajoules per kg. So 4000 kg requires about 24 gigajolues, so it's 24 GJ per square meter. A 600 km diameter sphere has a surface area of 4.5 trillion square meters, so the overall power release was 1x10^23J.

Which is roughly 25,000,000 megatons.

I think that is a tiny bit more than a gigaton.
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Re: Has Weber gone Ecofreak on Us? CoG Spoiler Alert!
Post by namelessfly   » Mon Apr 14, 2014 8:56 pm

namelessfly

kzt wrote:
Randomiser wrote:All that has been established is that a warship's reactors contain enough plasma tbat the sudden overpressure caused by it's expansion and the vaporisation of the area around the reactor is sufficient to shred the said warship into little pieces if containment fails. That is nothing like a Gigaton range explosion.

Perhaps you should reread chapter 46 of Echos Of Honor?

How much energy do you need to vaporize a half meter of Honorverse battle cruiser armor at 600 km from an omnidirectional explosion?

Well, we don't really know the characteristics of the armor, but I think it's safe to assume it's at least equal to iron in resisting damage.

A section of iron 1 meter square and .5 meters deep weights about 4 tons. The heat of vaporization of iron is about 6 megajoules per kg. So 4000 kg requires about 24 gigajolues, so it's 24 GJ per square meter. A 600 km diameter sphere has a surface area of 4.5 trillion square meters, so the overall power release was 1x10^23J.

Which is roughly 25,000,000 megatons.

I think that is a tiny bit more than a gigaton.
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Re: Has Weber gone Ecofreak on Us? CoG Spoiler Alert!
Post by namelessfly   » Mon Apr 14, 2014 11:53 pm

namelessfly

Actually, the fusion reaction rate and hence energy production is a function of the fusion reaction cross section fora given plasma temperature multiplied by the plasma density squared. Given the fact that PV=nRT applies to fusion reators as well as ideal gases, thismeansthat fusion reactors operate at extreme pressures unless you are fueling them with Tritium-Deuterium that produces a neutron flux that will transform your fusion reactor into radioactive slag. Given the fusion reactor physics that applies, the "attitude jets" that can accelerate a 2 million ton freighter at 20 gees will have a power density that is absurd. Aftercrunching the numbers some years back, I find it difficult to believe that such fusion reactors would not be prone to failure at multigigaton energy levels.

Of course a civilian power reactor installed on a planetary surface would operate with a much lower power density of less than one Gigawatt per ton (comparable to the NERVA fission reactors) so they would not be prone to catastrophic explosion. Given the prospect of operating an MHD generator with a hot temperature of tens of millions Kelvin and a cold temperature of a few thousand K, conversion effeciency would be 99% plus. However; all energy use would eventually be converted to waste heat.


Randomiser wrote:I don't think it has been established that "Honorverse fusion reactors blow up real good when you damage them". All that has been established is that a warship's reactors contain enough plasma tbat the sudden overpressure caused by it's expansion and the vaporisation of the area around the reactor is sufficient to shred the said warship into little pieces if containment fails. That is nothing like a Gigaton range explosion.

Also we know nothing about the thermal efficiency of an Honorverse fusion reactor in the civilian city power application. Maybe they have ways to turn heat directly into electricity at high efficiency, who knows? Can you set up a gravity gradient sufficient to slow the particles which hit it and extract the energy somehow? I seem to have missed the "applications of gravitics" course at school. By the way, what did you say the typical output of one of these residential tower reactors was?


A certain amount of low grade residual heat will be very useful for heating systems and hot water in the tower and surrounding industrial complexes, of course.
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