"Closed" Cycle Internal Reaction Engines

Bret Cahill wrote:


Not really, your talking about technology (mostly) designed to produced electric power. Once produced electric power is worth about 4 times as much as thermal sources like gasoline, disel or natural gas.
Of course that requires the changing of the infrastructure that exists to use power as well as produce it which significantly increases the cost involved. But if you make the electricty cheap enough the cost of oil will drive a more natural switch, hopefully.
Ideally you would figure out a way to generate H2 directly using low quality thermal input. That would allow you to take a CO2 generator (limestone/quicklime) and generate methane, disel, plastic precursors, fertilizers, pesticieds and all the other wonderful oil based products.
I noticed that no one mentioned OTEC or high altitude wind, both of those are relatively large scale systems as I understand it.
Ghostwriter
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ghostwriter wrote:

Both of those would be true environmental disasters if applied on a large-enough scale to be significant energy producers. See "anthropogenic climate disruption -- genuine".
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LongmuirG wrote:

Yet, you previously wrote: "Coby Beck is right -- anthropogenic global warming is unproved."
How is it your first claim is a sure thing yet gw is unproved?
Do you have an agenda?
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Dan Bloomquist wrote:

Not knowing one way or the other, but he may be saying that what we have now is not anthropogenic, but that we might create it.
Doesn't seem right though.
Steve
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steve wrote:

Well, the ops words were, "Both of those would be true environmental disasters..."
But when it concerns anthropogenic gw, he calls it a scam.

It doesn't. A very strange way to do science.

Best, Dan.
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Dan Bloomquist wrote:

Thank goodness you are still talking to me (or at least about me), Dan! Ever since I cracked that joke about the Hirsch Report, you have been -- well! -- distant.
We are talking about 3 different processes here; 3 quite different mechanisms for influencing global climate.
First, the standard politically-correct anthropogenic global warming model assigns the blame to increases in atmospheric CO2 at very low levels, Parts Per Million -- but strangely the politically-correct model blames only that part of anthropogenic CO2 related to fossil fuels, not the 40% or so of anthropogenic CO2 related to land use changes, primarily poor people in the Tropics cutting down forests. (Agenda, anyone?) And this focus on CO2 ignores the clear science that most global warming is due to water vapor, which is present in the atmosphere in concentrations that are orders of magnitude higher than CO2. (Agenda-driven poor science, anyone?) A measurable percentage increase in atmospheric CO2 corresponds to an insignificant increase in total radiatively active gases in the atmosphere. Yes -- anthropogenic global warming is indeed a scam. As the great Coby Beck once said so forcefully, it is also unproven.
Second, wind power works by slowing down the movement of air -- and the planetary circulation of air is the major element in global climate. On a small scale, wind power is irrelevant to climate, but unfortunately on a small scale it is also irrelevant to global energy demand. Extract wind power on the necessary tens of TeraWatt scale, with wind factories covering an appreciable percentage of the planet's surface, and this would indeed have a major anthropogenic influence on global climate. Admittedly, this issue is severely understudied. (Political agenda, anyone?). Dr. Keith at Carnegie-Mellon tried to investigate it, and now he does not live in this country anymore. (Remember Galileo, anyone?)
Third, extracting power from ocean temperature gradients is inevitably very inefficient thermodynamically, which means it would have to be done on a truly staggering scale to yield power at the relevant tens of TeraWatt level. Large scale (anthropogenic) alteration of surface water temperatures & deep water temperatures would have obvious impacts on global climate and on ocean ecology. Incontestable.
Yes, anthropogenic global warming is a scam, and large-scale wind power or OTEC would have major anthropogenic environmental impacts. So, Dan, what are you offering -- apart from snide comments?
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To be fair, all you have offered us is snide comments in which you pooh-pooh those effects that you happen not to agree with as "insignficant", and aggrandise those you do agree with as "stupendously significant". If you're going to call others snide and make assertions like that, you might want to cite some numbers, rather than just superlative adjectives that happen to suit *your* personal agenda.
Eric Lucas
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Eric Lucas wrote:

Mr. Lucas -- so nice of you to join the discussion. Next time you do, it would be helpful if you put some content in your post. Discuss the physics of the processes. Provide some numbers, if you think the discussion would benefit from numbers. But please don't put quotes around your own words -- "stupendously significant" -- as if you were quoting someone else; that really is misleading.
The fact that alleged anthropogenic global warming is a scam does not mean that other very large scale human activities could not have impacts. We need to be careful with words. Some activitists like to use renewable, green, environmentally-friendly as if they were synonyms -- but they are not. For example, hydro-power is called renewable, yet it has very obvious environmental impacts. Wind power would have impacts comparable to those of alleged anthropogenic global warming if used on a significant scale. Any energy source we use will have impacts, while not using any energy source at all would condemn most of the human beings on the planet to death. We are facing difficult choices about serious matters; there's no room for brain-dead political correctness.
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LongmuirG wrote:

Well, Mr. Lucas, I appreciate the 'content'. Mr. Longmuir is back to being relegated to the third person....

Haaaa. Mr. Longmuir makes a claim but demands 'proof of the contrary' from others. So typical.

But we will accept the 'fact' that 'high altitude wind' would cause irrecoverable damage. Gee, where are those numbers?

But Mr. Longmuir would argue that one is a puff of smoke while one would be the demise of our civilization!

Of course. How else to fool the uninitiated?
So usenet....
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Dan Bloomquist wrote:

Damn, Dan! You really did take those comments about the Hirsch Report too personally!
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LongmuirG wrote:

I have a problem with your scale. The average tempature change of the atmosphere in the last 50 years was 0.6 C(0.012C/year) (wikipedia:global warming). The generation of 300 exajoules (100% current world usage) at 1% efficiency would shift about 2joules per kilogram of water(thats assuming reuse of the cooling water in aquaculture or deep reinjection rather than just mass dumping on the surface). Thats 0.002C per year cooling of the surface about 20% of the effects of global warming and in the opposite direction. The only effect would a slowing of the increase in surface water tempature. Extensive use of shallow lagoon aquaculture would cancel even that effect out given the extra surface area of the lagoons.
I dont know the wind speed increases for that same time so cant calculate the effect on high altitude wind but since tempature is the major contrubuting factor to wind speed it is likley in the same order of magnitude.
Ghostwriter Ghostwriter
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ghostwriter wrote:

Presumably you mean the 300 ExaJoule figure to be annual "current world usage"? If so, it is out of date -- 2005 global commercial energy use was more like 440 ExaJoules. Further, we need to think about the 60% of the human race that is currently seriously underserved in energy. And we need to recognize the significant additional energy demand coming from using a very inefficient energy source such as the ocean temperature gradient. The real target energy production figure is more like 4,000 - 5,000 ExaJoule, using so-called renewable sources.
But your point is well taken -- lowering the average temperature of the oceans by only small amounts would potentially make very large amounts of energy available. However, your cooling estimate is wildly misleading because it assumes that we successfully cool the ENTIRE oceans of the globe evenly, all 70% of the planet's surface, coastline to coastline, surface to abyssal depths -- all 1.4 * 10^24 grams of it. Look at a globe: there are parts of the Pacific Ocean that are about 6,000 miles from the nearest continental coastline -- how would we cool the water there? how would we deliver energy extracted from that location to the point of use? Practically, use of ocean temperature gradients would mean much larger temperature drops over smaller parts of the ocean surface -- which would likely have anthropogenic global climate impacts analogous to the El Nino/La Nina phenomenon.
I don't follow your point about "shallow lagoon aquaculture". First, scale -- how does the area of those shallow lagoons compare to the 70% of the planet's surface covered by oceans? Second, what are they there for? Carry out a thought experiment -- you have two large insulated tanks in front of you. One holds warm water. The other holds cool water. Your job is to transform part of the energy in the warm water tank into mechanical work. How will you do it? (Hint -- you are going to need a working fluid). So what is in those shallow lagoons?
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LongmuirG wrote:

OTEC uses the warm surface water as the working fluid, a pressure gradient is established and used to lower the boiling point of the water below the surface tempature. The resultant steam is used to run a turbine. The deep water is then used in a heat exchanger to condense the surface water and maintain the pressure gradient. The result is a large amount of fresh water and salt water all at the weighted average tempature. The freshwater is used for irrigation and drinking, the salt water is pumped though shallow lagoons to deliver minerals for aquaculture. Between the aggitation in air and the solar area the energy that the OTEC extracted should of been returned to the water. That doesnt mean that the tempature isnt different but that the net heat is close. The water is then reinjected around 100meters underwater in the transitional area.
I was wrong in my math in my last post, the use of total water weight is incorrect since after about 500 meters the water tempature is very stable, but I also made another mistake I confused calories with joules, the actual tempature change would only be a 1/4 of my previous estimate, Taken together that actually they nearly cancel each other out since the vast majoity of the ocean's mass and heat are above 2000meters.
Since all the energy output of OTEC is electrial, nowhere near 440 Exajoules would be needed to mean current demand. Current energy use is only about 10-15% electrial and 85-90% thermal. Electrical energy is worth 3-4 times what thermal energy is since the ineffiencies of heat engines dont effect electrical systems. Carnot has been paid already.
Now that doesnt mean that you can hand wave away the massive expensive and work of changing the infrastructure but if you make electrical energy cheap enough the switch will occur naturally in order to take advantage of that cheap energy.
Ghostwriter
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ghostwriter wrote:

According to my old steam tables, the saturation pressure for pure water (not salt water) at (for example) 80 deg F is 0.5 psia. If you prefer metric units, that is about 0.03 Bar. In any system of units, it is a fairly high vacuum. Where is the energy going to come from to pull that vacuum? How heavy do the walls of the equipment have to be to withstand atmospheric pressure on the outside? (Check "Hemispheres of Magdeburg").
ghostwriter wrote:

Yes, I know. Your physics was not that great either. Nor have you addressed the question about the validity of your assumption that you could cool the entire oceans of the globe evenly.
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Gawd, I hate to do this, but...it's Dr. Lucas to you.

Sorry, paraphrasing...but not inaccurately, based on your gloom-and-doom assertions.

That's a truly amazing sentence. You set up an unsubstantiated strawman, and use tearing it down to support your other unsubstantiated claims. The vacuousness is mind-boggling.

Nor is there room for glib dismissals of well-supported science, or unsupported assertions of gloom-and-doom regarding potential new technologies. (For the record, my gut tells me that both of those new technologies--high-altitude wind energy and ocean thermal gradient harvest--are ridiculous ideas at best, and could very well be environmentally devastating if either were implemented successfully. However, notice that I don't say that as if it were fact, and I make it clear that it's only my gut feeling.)
Extraordinary claims require extraordinary evidence...and it is part of the duty of any competent scientist is to point out when somebody is trying to act the expert in an area when they have not met their burden. I'd say the vast preponderence of the evidence is in support of anthropogenic global warming, so I'd say that that camp has met their obligation (which you choose to glibly ignore). You, however, make the extraordinary claim of planetary doom from two potential new technologies. I'd say any prediction of planetary doom is prima facie extraordinary, and so requires extraordinary evidence.
You wanted "content in my post" (is that a direct enough quote to justify the quote marks?) Pointing out your failure to support extraordinary claims is valid content in any science discussion. I'm not saying you're wrong. I'm saying you haven't given enough information to be taken seriously.
Eric Lucas
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DOCTOR Eric Lucas (DOCTOR of what? we all asked) wrote, inter alia:

Sounds reasonable! So where is the "extraordinary evidence" for anthropogenic global warming?
Remember that the ordinary evidence is that the climate of this planet has been continuously variable for as long as we can determine, for hundreds of millions of years before any possibility of anthropogenic involvement. Remember also that the current climate is (to the limited extent that we can measure such things) well within the bounds of past natural variability. As a DOCTOR (of something), you surely must have a well-founded basis for your apparent support of alleged anthropogenic global warming?
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snipped-for-privacy@bellsouth.net wrote:

All of these alternative energy schemes fail to address the energy density required - a typical car has an engine that can deliver roughly 100kW at the wheels, and it can do that for maybe 6 hours at highway speeds on a tank of petrol.
Now refill the "tank" with any other current or planned energy source ? Suggestions please.
Steve
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Steve Taylor wrote:

600 driveshaft kWh? That would be a 58-gallon gasoline tank, so not a typical car, maybe a motorhome.

--- G. R. L. Cowan, former hydrogen fan Boron: internal combustion with nuclear cachet: http://www.eagle.ca/~gcowan/Paper_for_11th_CHC.html
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100kW power is only necessary to scoot across an intersection, a popular activity of dubious value to society.
On the highway you only need 10kW to cruise at 60 mph.
Engines are dirt cheap -- accounting for less than 10% of motor vehicle costs. It would be immediately cost effective to start putting two or even 3 engines in cars. No breakthroughs are even necessary.
What part of "trolling motor" do they NOT understand?
Auto manfacturers are just stuck on stupid.
Bret Cahill
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We don't need battery improvements of even an order of magnitude.
I've been wondering if there is some maximum limit type of law to energy densities of reactants that could lead to much better batteries.
Supposing the highest energy density obtainable reacting chemicals in an ideal heat engine was related to that of the same chemicals in some ideal battery?
We already know, assuming materials, heat transfer, etc. aren't problems, that the Carnot efficiency of an idealized H2 + O2 heat engine is well over 95%. A real life fuel cell is somewhat less.
If some other reaction than H2 was possible in heat engines, there might be a corresponding battery or fuel cell almost as good or, taking the temperature limitations of engine materials into account, several times better.
Bret Cahill
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