Plausible science-fiction energy ideas

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  • podcakepodcake Forumite
    116 Posts
    @podcake

    OK, I'll take a quick bite at this from my long distant physica lessons and too much SF reading (i.e. I like the spaceships in theory but don't ask me to plot the course...) :-)
    At a guess, what we're looking at here in terms of 2nd law stuff is the question of what is considered the system as a whole...
    In 1) pumping from "cold source" to "hot" : isn't that "apparent efficiency" related more to the larger quantity of heat collecting surface compared to a small heat emitting surface on the inside of the house, with the pump effectively "concentrating" the energy involved... net effect being no breach of 2nd law as you have a larger total amnt of energy at the collectors flowing with efficiency lost through the pump and thermal losses through intermediary piping etc
    2) Not too familiar with Stirling engine (rings a bell but a bit of googling to follow I suspect) but the idea seems similar to most other types of turning chemical energy via heat to mechanical energy - so far so pretty conventional and definitly no breach of 2nd law here

    1 & 2 combined - in order for this to be Perpetual Motion Engine(tm) we'd need the total numbers and limits for the system as a whole - I'd think that what would effectively happen is that you'd just more quickly locally cool the ground the heat pump is extracting from to the point where .... uh oh, just picked up on this - where is the Stirling engine getting it's heat from? hmmm....

    I think my brains to tired to work this one through... will have to reflect later on this, but hey, tell you what, you build us a working model and I'll swap it for this here Brooklyn bridge I have just here... :-)

    In the meanwhile - "Ye canna change the laws'a physics cptn!"

    LOL, it most certainly is an interesting one. I had the debate out with my Postgrad thermodynamics lecturer and he couldn't give a decent answer, so lets not either of us feel bad if we cant figure out all the specifics.

    The heat pump, imagine it like this:
    It is a lorry which uses 1 gallon of fuel for every 10 miles it travels, it drives ten miles with 4.5 gallons of fuel on board. if you measure how much fuel you put in (1 gallon) and compare it to the amount of fuel you now have at the depot (4.5 gallons) it appears that you have an efficiency of 450%. in actual fact you are taking the 'fuel' (ie: heat) from the earth.

    The Stirling engine gets it heat from the heat pump..

    In essence, the best answer that anybody can come up with that I've met was that it didn't break the laws of thermodynamics, it isn't perpetual motion because it has an energy input from the heat from the earth, which is then sunk into the atmosphere. The major issues revolve around the efficiency of the Stirling engine and the fact that it works over a temperature differential.. So.. it might well be possible.

    who knows, maybe one day i'll make one and see :P

    sorry to steal the topic, just an interesting one I've come across before!
  • Thanks again podcake - stirling engines are interesting and elegant, I can see now why they are so suitable for CHP systems.

    Seems to me that as much clever microgeneration on a local scale as possible by renewable methods is the way to go to relieve the carbon load off the grid for the short-medium term, with the remainder being provided by the big plant generators, most likely nuclear I expect, although I won't re-open here the great wind debate mentioned by celerity in the OP :D
  • celeritycelerity Forumite
    311 Posts
    podcake wrote: »

    Ah yes, this is the same story I read. I found the comments more interesting than the main article to be honest, hence my mention of salts. I'd love to be proved wrong, but I can't see the IR energy purely from the sky at night providing anything useful in terms of wattage.
    [silicon economy] I do know for a fact that solar panels (produced in the traditional way) require glass to encase them and a source of high quality silicon to manufacture them. As such I've got a feeling places with an abundance of these resources will start to more closely guard it.
    Isn't silicon widely available for just about any nation though? It's just sand after all...
    I can't really imagine a world where desert nations are jealously guarding their sand to be honest...
    [electric cars]
    Well, its probably best not to get me started on this. I have three directions that I can approach this from.

    1) I am a petrol head
    I did suspect this ;).
    There is no right or wrong answer about this, as everybody is different after all. Personally cars have never really excited me (I'd have more fun riding a race horse than drive a sports car) so provided an electric car satisfied my comfort requirements, had a usable range before it went flat and accelerated well enough that I wasn't humiliated at every slip road then I'd be happy.
    I do appreciate the "Top Gear" crowd have an opposing view though :).
    2) this one could be argued to be far fetched, but electric cars don't make any noise, which means that people who are 'stop look and listening' miss out one of these senses. Notably people with poor sight might not notice the electric car. This makes then a definite safety concern.
    This could be solved very easily if it were shown to be an issue (and I don't believe it would be) once a few hundred thousand leccy cars are on our roads. All you would have to do is add an artificial noise below say, 40mph. That should satisfy pedestrian crossing safety issues.
    Also, I wonder just how quiet electric cars really are. I'd love it if they truly were silent (I live fairly near a road, so traffic noise is one of my bug bears) but I suspect the noise I hear from any reasonably fast road is the vibration of the tyres and air turbulence caused by the cars - not the engines.
    3) I am an electronic engineer, and previously a parts fitter for a local automotive retailer, and I know all too well that batteries are bad news.
    Lithium ion batteries have a shelf life of something in the order of 1200 charge cycles (at a rate of one charge a day this means 3 years of use before they need replacing at significant cost both financially and environmentally).
    The emissions from the battery creation are horrendous.
    This is, I feel, your best argument. I haven't looked into environmental cost of making these batteries, but would hope it would get less once economies of scale start kicking in.
    A FAR better solution would be the use of hydrogen, which can be used alongside present Internal combustion technology with just a simple modification.
    This technology would certainly have its place over the next few decades. This thread is about beyond this time though, and I expect that hydrogen fuel cells within an electric car will eventually be more common.
    [biofuels] Well.. I am afraid to say I am as stubborn as a mule, and following an argument with a quite insistent vegetarian who accused me of everything under the sun I went away and proved mathematically that it was impossible for the whole world to be vegetarian based upon protein density, growing space etc....
    At the time it was quite rewarding to prove to him that HE was in fact the one being thoughtless, and not me who was 'killing' animals.
    (apologies if you are a veggie btw)
    Forgive me, but I think you are badly misguided if you think that is the case. I say this as a committed carnivore that couldn't even imagine going veggie, too :). Every time I've looked into vegetarians' claims that it is more eco-friendly to stop eating meat I've had to reluctantly conclude that they are right. It takes an enormous amount of crops to support just a few cows for example.

    I suppose you might be closer to being correct (but probably not) if we discounted eating fish, but that's a bit of an unfair cheat when the issue is land use...
    anyhow the outcome of this was that I know for a fact that we do not have enough land mass for food for everybody if we all turned veggie
    As noted, I think this is a false assumption.
    , as such the natural conclusion of this trend is that soon enough we won't have enough food regardless of how much meat we eat for the population to be healthy. As such, setting it aside for fuel is ridiculous, and it is only a matter of time before a crisis hits and an international organization has to step in and 'fix' it.
    OK, this explains your biofuel crisis prediction, and it makes a lot more sense in context. I could definitely see this kind of thing happening - it would only take a few nations to gamble on producing bio-fuels and then a few famines to drive the price of grain sky-high... [and keeping with the science-fiction theme, the book "[URL="http://en.wikipedia.org/wiki/The_Death_of_Grass"]Death of Grass[/URL]" by John Christopher is a classic analysis of what would happen to the world once grain becomes in short supply...]
    Also I apologize if I upset anybody with this post, I have some strong feelings on these topics.
    No need to apologise at all, your posts have been very interesting and I think lots of us on here have pretty strong feelings about the whole "global energy" topic.

    /\dam
  • celeritycelerity Forumite
    311 Posts
    Regarding Sterling Engines, doing some reading about Dean Kamen would be worthwhile. His inventions are all good candidates for the original subject of this thread!

    /\dam
  • podcakepodcake Forumite
    116 Posts
    Just a final note about the vegetarianism.

    Lets take the assumption that were we all to turn veggie overnight, there were no 'wasted cows' etc..

    My argument went something like this:

    'if you are calling me all the names under the sun because i eat cow, then for the purposes of the maths you cannot include any animal based protein. Also, due to the mass requirements of the swap you cannot include anything that requires a lab to setup the system, only natural vegetarian options are allowed to you.' there simply aren't enough supplements in the world to give everybody them, nor the facility to produce 'artificial protein' on the scales required.

    The food type which was worked with was mushroom because it was agreed that this could (most likely) be grown in the largest percentage of global areas, where other vegetarian mainstays would not thrive in colder climates (lets say Russia).

    We then agreed that the RDA was a value that was published following much research with regard to what was required for your health. It is, after all, a recommended amount. We accepted that this was 50 grammes or so.

    Mushrooms contain protein levels such that 1 cup of mushrooms was 2 grammes of protein. So basically, in order to eat your RDA of PROTEIN (probably one of the more important ones) you had to consume TWENTY FIVE CUPS of mushrooms:eek: per day!

    now, okay, mushrooms aren't the best for protein, BUT they have a fast grow time, which means if you lose a crop you aren't completely stuffed (plus it makes the maths easier).

    if you start to work it through, the grow time for mushrooms (forgetting the preamble) is in the order of 1 week- 10 days, so we need 7 crops minimum, with probably a 2nd area designated as being prepared ready for the next crops to grow. so we need 14 areas of growth, there are approaching 7,000,000,000 people on earth and only 12,000,000 miles^2 of workable arable land.

    assuming we COULD work all the land, you would need to (today) remove ALL crops from the land (internationally) and give it over in its entirety to mushroom growth for us to all even meet the worlds RDA of protein reliably.

    by comparison your meat eater (who is entitled to the animal products) need only have steak and chips or a curry (etc) for tea and milk with his cereal and he has basically met his RDA without even thinking about it. The cow which provided the meat also provides roughly 2,500 other portions and lived largely off grass.

    This example is a bit silly really, but at the time it was done to shut the chap up, who was not only being forceful about it all he was being downright rude, and accusing me of murder etc...

    in actual fact the real situation is far worse, because, whilst proteins are important true vegetarians (vegans) have problems taking on enough of lots of minerals and the such which are often scarce in non-meat produce. Bear in mind also, to accomplish this we would lose all growing space for potatoes, wheat, etc... so our available carb list would almost be 0....

    To sum up, if you do the maths, if everybody turned veggie, the world would starve. - or at least be unhealthy- (not to mention meat is more dense, so the transportation of commercial vegetarian goods costs the world more in terms of pollution than meat does assuming the veggies out there keep to the RDas and stay healthy..)

    Don't get me wrong, I have nothing against people who choose not to eat meat for whatever reason, This gent simply rubbed me up the wrong way...


    I was going to start to quote stuff of the internet RE: the prius, but i'll just offer this link instead:
    http://onemansblog.com/2007/03/27/prius-outdoes-hummer-in-environmental-damage/

    note the title 'PRIUS OUTDOES HUMMER IN ENVIRONMENTAL DAMAGE'
  • MikeyMacbethMikeyMacbeth Forumite
    146 Posts
    celerity wrote: »
    Ah yes, this is the same story I read. I found the comments more interesting than the main article to be honest, hence my mention of salts. I'd love to be proved wrong, but I can't see the IR energy purely from the sky at night providing anything useful in terms of wattage.

    Wasn't the IR energy converted from heat re-radiating from the ground rather than from the sky? - sort of a double sided Panel if I remember correctly.

    On a similar note - aren't "standard" solar PV panels optimised for just a small section of the visible light section? I seem to recall seeing somewhere that newer more efficient panels are layered to capture different bandwidths of light (and how is efficency measured for PV anyway? - conversion of visible spectrum light to electrical energy?) - I guess the "ultimate" solar panel would be one that converts every single photon of electromagnetic radiation that hits it, regardless of the angle it hits at! - is that sufficently Sci-Fi for you? :D

    PS forgot to mention another far-future energy source : capture/create and feed a quantum black hole and bask in the Hawking radiation - although maybe that's what they're up at the LHC these days anyway... :-)
  • MikeyMacbethMikeyMacbeth Forumite
    146 Posts
    celerity wrote: »
    Regarding Sterling Engines, doing some reading about Dean Kamen would be worthwhile. His inventions are all good candidates for the original subject of this thread!

    /\dam

    Although they'd have to be just a tad more, um, "revolutionary" than the Segway... :D
  • MikeyMacbethMikeyMacbeth Forumite
    146 Posts
    celerity wrote: »

    This could be solved very easily if it were shown to be an issue (and I don't believe it would be) once a few hundred thousand leccy cars are on our roads. All you would have to do is add an artificial noise below say, 40mph. That should satisfy pedestrian crossing safety issues.

    They're thinking about it already : BBC News - Should electric cars be made to go 'vroom'?

    Personally my favourite is the 50's flying saucer sound - that would ... just... so... cool!

    Ahem, I'll stop geeking now :-)
  • podcakepodcake Forumite
    116 Posts

    On a similar note - aren't "standard" solar PV panels optimised for just a small section of the visible light section? I seem to recall seeing somewhere that newer more efficient panels are layered to capture different bandwidths of light (and how is efficency measured for PV anyway? - conversion of visible spectrum light to electrical energy?) - I guess the "ultimate" solar panel would be one that converts every single photon of electromagnetic radiation that hits it, regardless of the angle it hits at! - is that sufficently Sci-Fi for you? :D

    Yeah, they experimented in the 1970s with panels that were geared towards working with the whole spectrum, the problem with them is to do with the way the different layers of electrons work. Basically the resulting panels were somewhat more expensive and yielded a similar output.. If you would like to know more I've got some notes I can paraphrase for you :).

    If you look up Prof I. M. Dharmadasa. He has some interesting papers etc. on how theoretical systems like this could work. ( I have in fact, been lucky enough to be lectured by him, and he is a very clever man) I think they have had experimental sucess, but the panels are unlikely to have been produced mass scale yet..
  • celeritycelerity Forumite
    311 Posts
    podcake wrote: »
    Just a final note about the vegetarianism.

    The food type which was worked with was mushroom because it was agreed that this could (most likely) be grown in the largest percentage of global areas, where other vegetarian mainstays would not thrive in colder climates (lets say Russia).

    I hate to say it, but this is honestly a really weak argument. The guy may have asked for it with his attitude, but I think you need to seriously reconsider the logic of it.

    It sounds like you are a bit fixated on protein (and mushrooms!), which honestly isn't so difficult to get from veggie sources. eg: http://www.vrg.org/nutrition/protein.htm

    The really important point is that farming animals for meat requires you to also farm for crops to feed the animals. So there is no way it can ever be a more efficient use of land to farm animals. Seriously :).

    As an aside, in the modern world we eat way too many calories anyway, and you really don't need meat to be a healthy athlete. For example, sumo wrestlers and some mixed martial arts fighters are veggie, but have physiques that might belie that. Also, there is growing evidence that ancient Roman gladiators were strictly veggie.

    Meat, I am afraid, is a luxury that perhaps one day we won't be able to afford as a species. Soylent Green anybody?!

    Like I say, I could never be a vegetarian, but I would never dare argue that my lifestyle choice is more eco-friendly than theirs, because it isn't!

    /\dam
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