Guest essay by Jan Kjetil Andersen
As Willis describes in his article on December 21, the atmosphere can be seen as a gigantic heat engine, i.e. a machine which convert thermal energy, namely temperature, into mechanical energy, namely wind.
It may seem a bit strange to view the weather system as a kind of machine and compare it with engineered constructs like an automobile engine, but it is sound physics because all such systems are bound by the same fundamental physical laws and they utilizes the same basic phenomena to create movement from heat.
A heat engine cannot convert heat directly to mechanical energy since that would break the second law of thermodynamics. What are needed are temperature differences. The greater temperature difference the greater effect of the machine. The amount of the energy in the temperature difference that is converted to mechanical energy is called the machines efficiency.
And here we have a very interesting, but less known fact of heat engines; the maximum theoretical efficiency decreases with increasing temperatures. This is interesting because it negates the conventional wisdom and often cited myth that a warmer climate leads to
more storminess, like the claim in the Guardian “a warmer planet has more energy to power stronger storms”, see http://www.theguardian.com/environment/2011/jun/27/climate-change-extreme-weather-2010.
Let us therefore take a look at the theoretical foundation of this effect. This is described by Carnot’s theorem.
Carnot’s Theorem says that the maximum efficiency drawn from a heat engine is the temperature difference between the warmest element and the coldest element divided by the temperature of the highest element.
Expressed as a formula it says: Emax = (Th-Tc)/Th.
Emax is the maximum efficiency
Th is the high temperature element measured in Kelvin
Tc is the cold temperature element measured in Kelvin.
The Carnot cycle is an ideal reversible cyclic process involving the expansion and compression of an ideal gas, which enables us to evaluate the efficiency of an engine utilizing this cycle.
For an interactive demonstration of the Carnot heat engine cycle, courtesy of the University of Virginia, click on the image:
Three important effects can be seen from Carnot’s theorem. The first is that a temperature difference is a necessary condition for converting heat energy to mechanical energy such as wind.
The second effect is that even if we had a perfect heat engine with zero internal friction; it would not achieve anything close to 100% efficiency. The maximum theoretical efficiency for a heat engine operating between 300 K and 600K is for example 50%. The efficiency of a real machine would of cause be considerably lower.
This is why our car engines only operate at about 25% efficiency. The warm element for a car engine is the exploding fuel inside the cylinders and the cold element is the air intake.
The best coal fired power plants have about 40% efficiency and the best gas powered about 55%. The cold elements for those plants are the coolant water, and those with highest efficiency utilize cold seawater as coolant.
Warming gives less efficiency
The third effect is as mentioned above, that, for a given temperature difference between the warm element and the cold element, the efficiency will decrease if both elements heat equally much. On cold days one can see a discernible effect of this in car engines; because the air intake is colder, the engine gives somewhat more power and higher efficiency.
This is also why some turbo charged engines have intercoolers. The turbo gives higher effect, but a non-intentional side effect is that it also increases the temperature in the air intake which will reduce the efficiency. The intercooler reduces the temperature increase introduced by the turbo.
The same effect applies to the wind formations in the atmosphere. Consider the summer temperature in the northern hemisphere; the cold element is the Arctic with a temperature of approximately 0 Celsius and the warm element is in the tropics with approximately 35 Celsius.
The Carnot theorem gives a maximum efficiency in this temperature range of 11.36%. If the temperature increased with 1 Celsius all over the globe, i.e. the difference changed to 1 Celsius in the Arctic and 36 Celsius in the tropic, the maximum efficiency would sink to 11.32%.
This is a minuscule difference, but the point is that it is a decrease, not an increase as the conventional wisdom will have it.
Less temperature differences on the surface
In addition to the effect of higher overall temperatures, the temperature differences will also be smaller. It is quite uncontroversial that the largest effect of global warming is on the cold polar winters and the smallest on the hot tropical summers.
![GFDL_CM2p1_SfcTemp_JJA_DJF_A1B_wht3200x2000[1]](http://wattsupwiththat.files.wordpress.com/2013/12/gfdl_cm2p1_sfctemp_jja_djf_a1b_wht3200x20001.png?quality=75)
However, to be fair, this is not all there is to this. Some climate models tell that the temperature differences in the upper troposphere will increase and this may have larger effect than both the reduced differences on the surface and the higher temperatures.
No settled science there.
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TB says:
December 28, 2013 at 4:23 pm
“No, not always, in jet disruption processes the jet can move E>W under a warm High in an Omega-block as deep cold air is advected west beneath. This is a common cause of the UK’s coldest winter events.”
I agree that some of time little jets may wander E>W, but virtually always W>E.normally.
Even during one of the most severe cold spells in the UK for decades at the time of year..
http://www.wetterzentrale.de/pics/archive/ra/2010/Rrea00120101201.gif
The jet hardly moved E>W.
http://virga.sfsu.edu/archive/jetstream/jetstream_atl/big/1012/10120106_jetstream_atl_anal.gif
The key component along with thermal gradient causing the jet stream, is cold very dry air meeting warm moist air.
The link before gave an example of this especially moisture related, when the cool dry polar air reached the moisture of the Atlantic ocean, but itself not warmer than the land masses to the West or East of it. that didn’t have a jet, but had relatively dry air.
http://virga.sfsu.edu/archive/jetstream/jetstream_atl/big/1307/13070406_jetstream_atl_anal.gif
Now that gravity has been introduced into this discussion, what effect does any atmospheric tides due to the moon have?
Bill H says:
December 28, 2013 at 2:23 pm
“It seems everyone want to go back to GHG’s rather than look at the functions of the heat transfer due to temperature imbalance/air mass movement. The more I look at this comparison to a Carnot Engine the GHG has little or no effect on the system when looked at from this point of view.”
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Not quite everyone..;-)
However, radiative gases* have a huge effect on atmospheric circulation. Without these gases, the atmosphere has no effective cooling mechanism. It is radiative energy loss at altitude that allows buoyancy loss, subsidence of air masses and continued tropospheric convective circulation in the Hadley, Ferrel and Polar cells. The result of this circulation is the pneumatically generated lapse rate cause by vertical circulation across the pressure gradient of the atmosphere. Just this factor alone makes our atmosphere far cooler on average than an atmosphere without radiative gases.
Some have claimed that the surface temperature differential between the equator and the poles could drive circulation powerful enough to generate the observed lapse rate in the absence of radiative energy loss at altitude. However the physics of gas conduction dis-allows this. The surface is far better at conductively heating a moving gas atmosphere in a gravity field than it is a conductively cooling it. The pole to equator surface temperature differential would not be realised in the gas atmosphere above. Further, surface friction and gas conduction within the atmosphere would would resist such circulation.
*the use of the term “greenhouse gases” as opposed to radiative gases is non-scientific. Use of that term is a wholly political effort to control the language to control the “narrative”. It implies that the radiative greenhouse effect is a valid hypothesis. In the case of both anthropogenic global warming and the radiative greenhouse effect, the hull hypothesis still stands.
I’ve enjoyed the two ‘heat engine’ articles. They are moving in the right direction, however, a better physical model for the earth system is what’s called a ‘Thermosiphon’ with a working fluid of water/’air’ mixture. In this case the primary working fluid is water because across the total delta T of the system (earth atmosphere) water is a three phase element.
It is also due to how those layers with different composition absorb energy directly from the sun.
The reversal of lapse rate in the stratosphere is primarily due to heating of that layer directly by absorption of UV ( UVB and UVC) by ozone. At the top of the stratosphere temperatures are only slightly below the freezing point of water. Above the stratosphere, the lapse rate again resumes but slightly steeper than in the troposphere due to the very low moisture content. The very top layers of the atmosphere are warmer again due to being actively heated by the sun through several mechanisms, direct energy absorption in the UV and x ray bands, heating due to effects of the solar wind, and electrical currents and dissipation of waves (like breaking waves at a beach) that develop in the very top layers of the atmosphere, and probably direct heat absorption from in falling dust and micrometeors into the upper layer of the atmosphere.
This is one of the problems with “simplified models” we often use to make sense of the mechanics of how heating in the atmosphere results in ground temperatures warmer than prevailing theory says the should be according to SB and why N&Z proposal about gravitational potential energy and how it defines the total warming not some trace gas in the atmosphere is so controversial.
Every time we try to simplify the situation too much to help get our head around the processes we simultaneously introduce false realities that sometimes become the focus of debate. People forget that in specialize thought experiments and analogies we sometimes set traps for ourselves and get sucked into debating some quirk of the “mental model” just like we do with “computer models” and lose site of the forest for the trees.
I can’t explain the exact physics of the gravitational heating hypothesis in the context of the real world, but I also cannot find any escape clause that would allow the conservation of energy considerations to be ignored.
I think we are in a position much like when scientists first began to realize that Newtonian physics did not work well in certain realms (the very small and the near light speed domains for example) and they first began to embrace quantum and relativistic considerations.
It is my expectation that once sufficiently open minded researchers start looking for and gathering the appropriate data instead of just presuming GHG’s are the cause of heating we might finally dig out the exact mechanics. You obviously cannot prove or disprove a concept you refuse to even investigate, or you presume is so well grounded that it need not be examined in light of new information.
Just like we complain that the AGW advocates are only looking for confirmation and not falsification, we need to be careful not to look only for confirmation of a gravity based lapse rate but also those tests which would specifically prove it could not be true. This does not include just declaring it must be nonsense but actively defining what must be true if it is valid and what test would prove that it fails. To do that we first need legitimate methodical unbiased experiments that examine if it might exist and making reliable repeatable tests of various explanations for what N&Z pointed out in their papers.
Waving your hands and saying it cannot be true is no more valid than waving a computer print out and saying “the models say so”.
jorgekafkazar says:
December 28, 2013 at 4:02 pm
chris y says: “The cyclone wind speed v can be estimated with this model and other assumptions, giving
v = sqrt((Ts – To)E/To)
where Ts=300K, To=200K and E is a variable related to coupling efficiency of energy between the ocean surface and the atmosphere.”
There’s the problem with your analysis. E, the coupling efficiency, is a temperature-related variable, and could reduce the velocity or even send it the other direction.
****************
For the record, this is Kerry Emanuel’s analysis, not mine.
I agree that E is likely temperature dependent. However, at least some of the temperature dependence of the energy coupling between ocean and air has already been accounted for in the model.
There are other problems with using the Carnot model for cyclones, like energy transport with water vapor.
Glad to see we are finally getting some examination of the atmospheric-heat engine aspect of the earth, but how about the rotation of Earth in the Sun’s magnetic and gravitic fields? The rotating field of Earth should act like a both generator and motor one would think, and the tides rise and fall several feet, which must involve quite a lot of heat energy moving all that water. Are there tides in the core as well? Piers Corbyn’s solar powered weather forecasts also shows a correllation between solar activity and earthquakes. Is there electromagnetic and gravitic heating in our planet?
DonV says:
December 28, 2013 at 3:04 pm
Steve B says
“No the primary working fluid is the air. The oceans are a moderator not a driver.”
I’m sorry but I disagree. I chose my ‘ammonia refrigerator’ example for a reason. In this refrigerator the energy source is heat from a kerosene flame. There are three molecules trapped in the system – Water, Anhydrous Ammonia, and Hydrogen. The water never boils, and the hydrogen never condenses. Only the ammonia CHANGES PHASE. So the working fluid is ammonia, not water and not hydrogen (although both are needed to make the system work efficiently). It is the ammonia that does the heavy lifting, that stores and then releases the vast majority of the heat transferred in this system.
********************************************************************************************************************
Well you may disagree but our atmosphere is not a refrigerator. The process is the movement of hot air and cold air which I believe we call wind. Wind is created when there is a differential between hot and cold air not hot and cold water.
chris y says: “The cyclone wind speed v can be estimated with this model and other assumptions, giving v = sqrt((Ts – To)E/To), where Ts=300K, To=200K and E is a variable related to coupling efficiency of energy between the ocean surface and the atmosphere.”
jorgekafkazar says: There’s the problem with your analysis. E, the coupling efficiency, is a temperature-related variable, and could reduce the velocity or even send it the other direction.
chris y says: For the record, this is Kerry Emanuel’s analysis, not mine.
jorgekafkazar says: Noted. This was only one of your three points, and it originated with Emanuel’s paper, as you stated.
chris y says: I agree that E is likely temperature dependent. However, at least some of the temperature dependence of the energy coupling between ocean and air has already been accounted for in the model.
jorgekafkazar says: The quantification remains moot, models being only models.
chris y says: There are other problems with using the Carnot model for cyclones, like energy transport with water vapor.
jorgekafkazar says: ” Agreed, but I’m unconvinced that the inclusion of a water vapor cycle will result in increasing efficiency, rather than decreasing. I strongly suspect that more evaporated water vapor will not produce more available energy for wind velocity. Most of the extra energy will be (1) lost through vertical convection or (2) expended as latent heat converted to potential energy, which is ultimately lost in rain impacting the oceans’ surface.
Larry Ledwick says:
December 28, 2013 at 5:21 pm
—————————————————–
The N&Z hypothesis does appear to work, however Willis was correct to point out flaws in their maths. There was a quite heated “discussion” here at WUWT about Equation 8 in a series of threads that would probably be best referred to as “the past unpleasantness”.
The N&Z hypothesis will only hold true for atmospheres exhibiting strong vertical circulation allowing non-radiative energy transport to exceed the speed of gas conduction and a lapse rate to develop.
The good news is that all planets and moons in our solar system that have managed to retain an atmosphere have sufficient radiative gases to allow the radiative cooling necessary to drive this circulation.
DonV, excellent observation Re the 2 phase working fluid. The third phase (ice) is simply reserve or stored heat capacity in the system.
The data in the bloggarticle above is only one out of many where incorrect data is used to prove (sometimes disaprove) thesis drawn from incomplete datamodels.
Btw. Since 1964 (Nineteen sixtyfour !) true readings of all discussed in the blogg article been made. Where? Esrange, Sweden.
Further more: Wouldn’t it had been a good thing to use at least one of the best Dissertations in the field as a background check?
For example:
Nikulin Grigory, Impact of Rossby waves on ozone distribution and dynamics of the stratosphere and troposphere , Dissertation Umeå University 2005 ISBN 91-7305-946-3
IRF scientific report, 0284-1703 ; 285
Very nice article, which simplifies the understanding of delta T which is responsible for “weather”.
I’m just nit picking. The statement: “The warm element for a car engine is the exploding fuel inside the cylinders and the cold element is the air intake” Is correct in what point is being made –except, car nuts don’t like to call the burning an explosion. It is really a controlled burn. The flame front is well controlled so that the energy can effectively convert heat into mechanical motion when it is needed, and then expelled. Sparks are timed to detonate before the piston reaches top dead center due to the latency of pressure wave. Explosions in the cylinders are very bad and screw up the timing required for engine performance.
The other point in support of this need for delta T for more weather energy is that warmer air at the poles is less dense, so there are fewer molecules of colder air to react with the warmer equatorial air.
Thank you for the article!
Thanks Jan for your explanations.
There are numerous papers on climate as a heat engine. e.g. see Google scholar: “carnot heat engine climate warming temperature difference wind”
e.g., Alex Kleidon finds:
Axel Kleidon How does the Earth system generate and maintain thermodynamic disequilibrium and what does it imply for the future of the planet? Philos Trans A Math Phys Eng Sci. 2012 March 13; 370(1962): 1012–1040. doi: 10.1098/rsta.2011.0316 PMCID: PMC3261436
Mazzarella et al. show CO2(temperature) variations are associated with variations in the earth’s Length Of Day (LOD) i.e., by changing the differential temperature which changes the wind /ocean current speeds.
Mazzarella A., A. Giuliacci and N. Scafetta, 2013. Quantifying the Multivariate ENSO Index (MEI) coupling to CO2 concentration and to the length of day variations. Theoretical and Applied Climatology 111, 601-607. DOI: 10.1007/s00704-012-0696-9. PDF
Konrad said:
“The good news is that all planets and moons in our solar system that have managed to retain an atmosphere have sufficient radiative gases to allow the radiative cooling necessary to drive this circulation.”
In fact, the necessary convective overturning is induced by uneven surface heating causing air parcel density differentials plus the gravity induced decline in temperature with height which allows the uplift of less dense parcels.
Radiative cooling within the atmosphere is not needed.
If the atmosphere is radiatively inert then the effective radiating height stays at the surface and convective overturning settles at a speed which delivers kinetic energy back to the surface via adiabatic warming on descent sufficient to supply the energy needed by the surface to radiate as much to space as is received from space.
Fantasies about isothermal atmospheres are not realistic.
A heat engine model is just another model, one containing a kernel of truth, but fraught with oversimplifications just as the GCM’s. The delta T between the equator and poles is modulated by the fence effect of circumpolar vortices. When these vortices are strong, they limit the Rossby wave amplitude we perceive as extreme weather.
As Willis has suggested many times there seems to be a system limit to tropical atmospheric warming that would affect the meridional delta T. Such a limit would flatten the gradient in a warming environment, pretty much what we are seeing with hot polar atmospheric anomalies.
The ocean is another story…
Larry Ledwick says:
December 28, 2013 at 5:21 pm
I said:
“That is why the Earth’s lapse rate is like a sideways ‘W’ due to composition variations as one goes up. That ‘W’ shape is a consequence of the circulatory contortions necessary to net out to the ‘ideal’ gravity induced lapse rate.”
Larry said:
“It is also due to how those layers with different composition absorb energy directly from the sun.”
Yes, I agree.
But the distortions in the gravity induced lapse rate created by direct absorption from the sun are also ‘corrected’ by circulation changes.
Even the stratosphere has a circulation albeit very slow due to low air density and I suspect similar movements in the higher layers too but they would be so weak that they have never been measured.
Suffice it to point out that if internal system parameters could cause a long term net divergence from the ‘ideal’ lapse rate then the atmosphere could not be retained.
Konrad said:
“The surface is far better at conductively heating a moving gas atmosphere in a gravity field than it is at conductively cooling it”
Due to the density differentials between surface and air one would think that but bear in mind that the surface can only cool to space radiatively so an adiabatically warmed descending column of air only needs to deliver enough kinetic energy back to the surface to at least partially offset energy radiated upward. Even a partial offset will increase average global surface temperature.
In the middle latitudes we all know of clear winter nights when it is windy and the air movement prevents a frost from developing by inhibiting net radiative loss from the surface.
Direct conductive energy transfer from air to surface is not needed. Just offsetting radiative loss is sufficient to warm the surface higher than S-B would predict in the absence of an atmosphere.
I must say that I am very pleased to see this article. I find it validating of many of the things I have been trying to say for a very long time. It is not heat that causes storms, it is a DIFFERENCE in temperature and that difference can be created by either cooling one side or heating the other. It is my opinion that glacial periods would be extremely and freakishly stormy in the central US. This is because solar insolation at lower latitudes remains relatively constant, it is high latitude isolation that changes most greatly. During glacial periods, the Gulf of Mexico and tropical Atlantic is still receiving about the same amount of energy it does in the interglacial periods but imaging you have a warm gulf of Mexico and severe cold in the upper plains and very cold air in summer coming down off the ice into the central plains. We SHOULD see absolutely terrific storms. We would likely have fronts spawning tornadoes nothing like what we see today.
I would not want to live in places like Oklahoma during the glacial periods for I fear massive tornadoes would be much more common then than today considering a great ice sheet would be nearly as far away as the Gulf of Mexico.
The idea that radiative (or any other) cooling is needed to drive air down in Hadley circulation nakes no sense. It makes even less sense to consider the uoward and downward “parts” of convection separately. When any fluid is heated from below turbulent conveection will begin at a certain temperature gradient. Think of Rayleigh-Benault convection, or Libchaber’s experiments with liquid helium, or just water in a saucepan over a gas flame. Rolling cells represent the early bifurcations in the onset of, turbulence. This is what Hadley cells are. The asymmetric heat input exists at the outset of the turbulence as the causative factor it does not need asymmetric cooling to sustain it.
This is reductionism gone mad. Chaotic turbulence is not a clockwork machine – “machine” is a very bad analogy.
Stephen Wilde says:
December 28, 2013 at 9:01 pm
——————————————————
“In fact, the necessary convective overturning is induced by uneven surface heating causing air parcel density differentials plus the gravity induced decline in temperature with height which allows the uplift of less dense parcels.
Radiative cooling within the atmosphere is not needed.”
Stephen,
you keep insisting that uneven surface heating can drive vertical circulation across 10 to 15 Km of the troposphere. This is contradicted by empirical experiment. In tall gas columns, Rayleigh Bernard circulation requires energy loss at a higher point than energy input. Heating and cooling at disparate locations at the base of the column simply causes weak horizontal circulation, resisted by surface friction, with layers above this rising to toward surface Tmax. While the atmosphere may appear shallow, the pressure gradient creates a far greater virtual height in terms of Rayleigh Bernard circulation.
There is no “gravity induced decline in temperature with height”. There is a gravity induced pressure gradient. It is vertical circulation across this gradient that pneumatically generates the observed lapse rate. Without vertical circulation fast enough to overcome the speed of gas conduction, the lapse rate would disappear and the atmosphere would trend toward isothermal.
In arguing for strong vertical tropospheric convective circulation in the absence of radiative cooling at altitude, you have aligned yourself with Joel shore, Nick Stokes and sadly Kevin E. Trenberth.
Not even Dr. Pierrehumbert wanted to go that far. In 1995 he tried the far more subtle – “Well of course initially radiative gases start vertical tropospheric circulation and cause atmospheric cooling, but, uum, err, after a certain point the unicorn to rainbow ratio goes negative and radiative gases then cause atmospheric warming and anyway, err, uum, just shut up!” (Delivery of these claims does require hand-waving at near humming bird speeds).
The power of radiative cooling at altitude is huge. Radiative gases are radiating as LWIR to space more than TWICE the net flux radiative flux into the atmosphere from surface and directly intercepted solar combined. They are also radiating to space all the energy entering the atmosphere through surface conduction and the release of latent heat.
You are claiming that atmospheric conduction back to the surface could match this and generate vertical circulation fast and high enough to generate the currently observed lapse rate. The physics of gases in a gravity field say no way, no how. The surface is far better at conductively heating the atmosphere than it is a conductively cooling it. During the day, gravity moves colder gas to the surface maximising conductive flux into the atmosphere. During the night, gravity moves colder gas to the surface minimising conductive flux out of the atmosphere.
If your atmospheric model requires strong vertical tropospheric circulation to continue and the observed tropospheric lapse rate to exist in the absence of radiative gases, then your model has failed for the same reasons as the AGW and RGE hypotheses fail.
“The second effect is that even if we had a perfect heat engine with zero internal friction; it would not achieve anything close to 100% efficiency. The maximum theoretical efficiency for a heat engine operating between 300 K and 600K is for example 50%. The efficiency of a real machine would of cause be considerably lower.”
Ah, I wonder if this would apply to what I call a pipelauncher.
I would say this thing I call a pipelauncher as very efficient heat engine.
Converting heat into vertical velocity. And heat engine which could operate
between 300 K and 600K. Or perhaps between 200 K and 500K. But
could work as efficiently between 300 K and 400 K.
Details of it are a large pipe with one end capped.
Which place in the water, so floats vertical.
That is the engine.
Fuel can be anything. And it needs air and oxidizer for fuel.
Purpose of this pipelauncher is to be a launch pad and to lift
a rocket vertically. So it will lift hundred to tons relatively fast.
Or with acceleration of 1/2 gee or 1 gee. Or can do much higher
acceleration if rocket can withstand such gee loads.
In order to accelerate a rocket to any speed- 50 to 300 mph.
One needs the pipe to be quite long- so longer than 500 feet in length.
And to remain vertical and support rocket so it’s vertical, it needs
lengths longer than rocket is tall. So both reasons: 500 feet or longer
in length.
And to lift and accelerate a rocket weighing more than say 100 tons
the pipelauncher needs a large diameter.
So a large diameter pipe which is long and has one end capped.
Capped end is at the top. Rocket place on the top of cap.
And rocket needs some kind launch tower, which should weigh
less than 100 tons.
The pipe itself might weigh about 500 tons or more. Depends
what size of rocket will launched from it. And more tonnage of
course increases the overall. The cost per ton could $1000 to
say $3000 per ton. Cost of metal and fabrication into a large
pipe. One could use steel. Aluminum costs more but due lower
mass has less use- more efficient energy usage per launch.
But one may only do 50 to 100 launches in over many years
it could less money saved.
Other just energy use, aluminum can give higher performance-
heavier or faster launch speeds.
So anyhow regarding efficiency. So this machine works by
buoyancy, hence why I think it would be very efficient heat engine.
So this is like balloon, but instead air, one is using denser water
as weight which is displaced. Or It’s like ocean ship which goes
vertically.
So say it’s 20 feet in diameter and 600 feet long.
With one end capped.
You put in water, and open end will fill with water and
cause the capped end to float vertically.
If were to pump out the water in the pipe, the capped
end would rise, and eventual flop over. fill up and again
and flip vertical again.
In terms the operation involved with a launch rocket, you don’t
want it to flop over. You can tow it a location by temporary capping
the other end and towing it horizontally to some location in the ocean.
One would probably want to tow it to location at equator, which
is best location to launch rockets.
As engine it works this way. When vertical in ocean, the air inside
the pipe will push the water inside the pipe below the sea level.
How deep the water is pushed under the water, determines it’s
displacement or it’s buoyancy.
So as example the 600 foot long pipe which 20 in diameter may
be pushing the water 33 feet under sea level. Since 33 feet
under seal level is a atm of pressure, the air in pipe will be 14.7 psig
So pipe might weigh 500 tons. If add 500 ton of rocket, then
air pressure will be 2 atm [29.4 psi]. If double pressure inside, so
56.8 psi, and you keep the air pressure at 56.8 psi, the pipelauncher
and rocket accelerates at 1 gee [9.8 m/s/s].
So what you need is a lot of air. So you use liquid air. If you dump
1 ton of liquid air into 1 ton of sea water you get gaseous air, once
warm water is instantly cooled, shouldn’t get so cold as to make ice.
So, generally you pour say 20 tons of liquid air into water inside
the pipe, and pour over say period of 5 seconds. You also want to
heat the air created. So say you burn kerosene or natural gas and
have peak temperature be say 400 K. And that about how much
you need to have pipelauncher and rocket on top it accelerate
vertical at 1 gee for 5 seconds.
So pressure range of air would be in range of 10 to maybe 80 psi.
And one can contract the exisingt air in pipe by misting liquid air.
So it’s operational air temperature could at extreme ranges of
150 K to 500 K. And one is only trying to warm or cold the air
and the time involved would be somewhere around 20 seconds
though actual launch time would less than 10 seconds.
So walls of pipe do not have enough time to be heated or cooled
much by the air.
Which means no heat radiated from pipelauncher and pipelauncher
can partially [or if crazy about it, fully] powered by ambient heat of
environment.
So in terms heat efficiency related mechanical motion, it seems like
this would be quite efficient.
Bill H – Dec 28 1:19 pm – “They miss the very basic concept of what is driving the air mass changes :. Maybe they don’t know what causes storms, but the chart I referred to is of observed storm tracks, and there are a lot more of them during the global cooling period than during the global warming period.
Tsk Tsk says:
December 28, 2013 at 10:11 am
Correct, Tsk, this is as I explain a bit further down in the sentence
“For a given temperature difference” means the same as “increasing equally”.
Finally, the cold sink in your car example is the air at the exhaust (and ambient air around the engine) and not the intake. They happen to come from the same pool but in principle they don’t have to. I could have a tank of hot air that I inject into the cylinders, expand, and exhaust and still get work from the system.
No, the work comes from the pressure created by the temperature increase caused by burning fuel in the cylinder. It is therefore the intake air temperature that counts.
If your claim was correct you could stop an engine by making some arrangements from the exhaust pipe to lengthen it into a bonfire. But, do you really think that would have any effect?
/ Jan
Doug Huffman says:
December 28, 2013 at 8:52 am
Carnots physics apply to all arrangements creating mechanical energy from thermal energy. The point is that you cannot get around it independent of how complex or simple the system is.
/ Jan