Guest Post by Willis Eschenbach
I noted on the news that there is a new plan afoot to cool down the planet. This one supposedly has been given big money by none other than Bill Gates.
The plan involves a fleet of ships that supposedly look like this:
Figure 1. Artist’s conception of cloud-making ships. Of course, the first storm would flip this over immediately, but heck, it’s only a fantasy, so who cares? SOURCE
The web site claims that:
Bill Gates Announces Funding for Seawater-Spraying Cloud Machines
The machines, developed by a San Francisco-based research group called Silver Lining, turn seawater into tiny particles that can be shot up over 3,000 feet in the air. The particles increase the density of clouds by increasing the amount of nuclei contained within. Silver Lining’s floating machines can suck up ten tons of water per second.
What could possibly go wrong with such a brilliant plan?
First, as usual the hype in this seems to have vastly outpaced the reality. According to CBS News Tech Talk:
The machines, developed by a San Francisco-based research group called Silver Lining, turn seawater into tiny particles that can be shot up over 3,000 feet in the air. The particles increase the density of clouds by increasing the amount of nuclei contained within. Silver Lining’s floating machines can suck up ten tons of water per second. If all goes well, Silver Lining plans to test the process with 10 ships spread throughout 3800 square miles of ocean. Geoengineering, an umbrella phrase to describe techniques that would allow humans to prevent global warming by manipulating the Earth’s climate, has yet to result in any major projects.
However, this is just a quote from the same web site that showed the ship above. CBS Tech Talk goes on to say:
A PR representative from Edelman later sent me this note from Ken Caldeira of the Carnegie Institution for Science: “Bill Gates made a grant to the University of Calgary to support research in possible unique solutions and responses to climate change. Administrating this research funding, David Keith of the University of Calgary and I made a grant to Armand Neukermanns for lab tests to investigate the technical feasibility of producing the fine seawater sprays required by the Latham cloud whitening proposal, one of many proposals for mitigating some of the adverse effects of climate change. This grant to Neukermanns is for lab tests only, not Silver Lining’s field trials.”
So Bill Gates isn’t funding the ships, and didn’t even decide to fund this particular fantasy, he just gave money to support research into “possible unique solutions”. Well, I’d say this one qualifies …
Next, after much searching I finally found the Silver Lining Project web site. It says on the home page:
The Silver Lining Project is a not-for-profit international scientific research collaboration to study the effects of particles (aerosols) on clouds, and the influence of these cloud effects on climate systems.
Well, that sure sounds impressive. Unfortunately, the web site is only four pages, and contains almost no information at all.
Intrigued, I emailed them at the address given on their web site, which is info(a)silverliningproj.org. I quickly got this reply:
Delivery has failed to these recipients or distribution lists:
info@silverliningproj.org
The recipient’s e-mail address was not found in the recipient’s e-mail system. Microsoft Exchange will not try to redeliver this message for you. Please check the e-mail address and try resending this message, or provide the following diagnostic text to your system administrator.
Hmmmm … not a good sign, four page web site, email address is dead … but onwards, ever onwards. Let’s look at a few numbers here.
First, over the tropical oceans, the rainfall is typically on the order of a couple of metres per year. Per the info above, they are going to test the plan with one ship for every 380 square miles. A square mile is about 2.6 square km, or 2.6 million square metres. Three hundred eighty square miles is about a thousand square km. Two metres of rainfall in that area is about two billion tonnes of water …
They say their ships will suck up “ten tonnes of water per second”. That’s about a third of a billion tonnes per year. So if they run full-time, they will increase the amount of water in the air by about 15% … which of course means 15% more rain. I don’t know how folks in rainy zones will feel about a 15% increase in their rainfall, but I foresee legalarity in the future …
Next, how much fuel will this use? The basic equation for pumps is:
Water flow (in liters per second) = 5.43 x pump power (kilowatts) / pressure (bars)
So to pump 10,000 litres per second (neglecting efficiency losses) with a pressure of 3 bars (100 psi) will require about 5,500 kilowatts. This means about 50 million kilowatt-hours per year. Figuring around 0.3 litres of fuel per kilowatt-hour (again without inefficiencies), this means that each ship will burn about fifteen million litres of fuel per year, so call it maybe twenty five million litres per year including all of the inefficiencies plus some fuel to actually move the ship around the ocean. All of these numbers are very generous, it will likely take more fuel than that. But we’ll use them.
Next, the money to do this … ho, ho, ho …
You can buy a used fire fighting ship for about fifteen million dollars, but it will only pump about 0.8 tonnes/second. So a new ship to pump ten tonnes per second might cost on the order of say twenty million US dollars.
You’d need a crew of about twelve guys to run the ship 24/7. That’s three eight-hour shifts of four men per shift. On average they will likely cost about US$80,000 per year including food and benefits and miscellaneous, so that’s about a million per year.
Then we have fuel costs of say US$ 0.75 per litre, so there’s about ten million bucks per year there.
Another web site says:
A study commissioned by the Copenhagen Consensus Centre, a European think-tank, has estimated that a wind-powered fleet of 1,900 ships to cruise the world’s oceans, spraying sea water from towers to create and brighten clouds, could be built for $9 billion. The idea would be to operate most of the ships far offshore in the Pacific so they would not interfere with weather on land.
My numbers say $38 billion for the ships … and “wind-powered”? As a long time sailor, I can only say “get real” …
However, that’s just for the ships. Remember that we are talking about $11 million per ship for annual pumping fuel costs plus labour … which is an annual cost of another $20 billion dollars …
Finally, they say that they are going to test this using one ship per 380 square miles … and that they can blanket the world with 1,900 ships. That makes a total of around three quarters of a million square miles covered by the 1,900 ships.
The surface of the world ocean, however, is about 140 million square miles, so they will be covering about half a percent of the world ocean with the 1,900 ships. Half a percent. If that were all in the Pacific Ocean per the citation above, here’s how much it would cover:
Figure 2. Area covered by 1,900 cloud making ships.
Yeah, brightening that would make a huge difference, especially considering half of the time it wouldn’t even see the sun …
See, my problem is that I’m a practical guy, and I’ve spent a good chunk of my life working with machinery around the ocean. Which is why I don’t have a lot of time for “think-tanks” and “research groups”. Before I start a project, I do a back-of-the-envelope calculation to see if it makes sense.
My calculations show that this will cost forty billion dollars to start, and twenty billion per year to run, not counting things like ship maintenance and redundancy and emergencies and machinery replacement and insurance and a fleet of tankers to refuel the pump ships at sea and, and, and …
And for all of that, we may make a slight difference on half a percent of the ocean surface. Even if I’ve overestimated the costs by 100% (always possible, although things usually cost more than estimated rather than less), that’s a huge amount of money for a change too small to measure on a global scale.
Now Bill Gates is a smart guy. But on this one, I think he may have let his heart rule his head. One of the web sites quoted above closes by saying:
The Bill and Melinda Gates Foundation did not respond to requests for comment on Tuesday, nor did U.S. entrepreneur Kelly Wanser, who is leading the Silver Lining Project.
Smart move … what we have here is a non-viable non-solution to a non-problem. I wouldn’t want to comment either, especially since this non-solution will burn about 27 billion litres (about 7 billion US gallons) of fuel per year to supposedly “solve” the problem supposedly caused by CO2 from burning fuel …
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It would save a great many electrons if contributors to this thread downloaded the paper on sea-going hardware published by the Royal Society and THEN did their calculations. But quickly, the power needed to spin Flettner rotors is between 5 and 10% of that needed to get the same thrust from a propeller. We are not pulling ourselves up by our own bootlaces. With expensive oil the Flettner system will come back. It failed because of the 1929 depression and very cheap bunker fuel. The salt quantity needed for cloud nucleation is a tiny fraction of what is put into the atmosphere now by breaking waves: we just put it up with the very best size for nucleation and most will fall back in the sea before it reaches land. We need a small amount of surface tension energy to make a drop with a diameter of 0.8 microns. When it gets into the cloud it will take water from a typical 25 micron drop and so produce two 19 micron ones. These two have a greater reflecting area than the single 25 micron one. If these last goes on for 24 hours ( and the best estimate is about 60) the solar energy reflected is billions of times more than we needed to make the original 0.8 micron nucleus. Nature hates uneven concentrations and uses turbulence to spread things out evenly. The salt residues are moved to the clouds by turbulence in the marine boundary layer.
The forces on spinning cylinders rise with the first power of wind velocity not the square as with sails. The heeling moments on Flettner’s ships were much less that those on the bare rigging of the conventional sister ship. His first were made from steel and weighed one quarter of what they replaced. We can do even better with Kevlar and carbon fibre. The spacing of the trimaran amas is chosen to prevent capsize in a category 4 hurricane. The rotor head contain buoyancy to give recovery. If you can fly unmanned planes over Afghanistan you can have unmanned sailing ships in mid ocean.
In official reports ducks scored highly on almost every count. The problem is that the initial installation size has to be at least 60 MW which is too big a risk at this stage of development of wave energy. Once confidence has built up we will be glad to make the best use of our sea frontage.
“Is it April the 1st? I don’t know about ‘legalarity’…more like ‘total hilarity’!”
This is extremely embarrassing for the reputation of the University of Calgary. Fortunately there is a new Dean – perhaps this will be addressed. Obviously this is totally impractical. It would be simpler and would cost less to increase sulfur emissions from industry and build more coal fired plants…oops I forgot – this is exactly what is already happening in China and India – only in the West is there a moratorium on new coal-fired plants and stringent emissions control.
Sulfur particles are well known to seed clouds.
I suspect this kind of research will involve plenty of trips (sailing, scuba diving and water quality/clarity evaluation) in the Caribbean to gather crucial data….of course, this is just Phase 1. So wax you surf boards Professors!
annav (and also Julian Flood)
“I do not think megajoules are being wasted in the exhaust of the ships engines.”
There are reasons why we have mininum temperatures on stack emissions. One is condensation of combustion products which would cause acid formation and corrosion within the stack.
The other is plume buoyancy. We want combustion products (stack) or water vapour (cooling tower) to rise and disperse in the middle atmosphere. As buouancy works on temperature differential, a flow of heat energy is required. That means power is supplied to the gases to create the plume. Much the same as the burner at the bottom of a hot air balloon.
So it is not quite wasted megajoules, but putting megawatts rejected heat to some useful purpose. But, yes, it does take power to get the plume to rise.
Returning to my earlier point, the world is awash with industrial activities and plumes which reliably raise massive qantities of gas and water vapour into the middle atmosphere. Some are stacks, carrying aloft the combustion products from fossil fuels. Some are cooling towers (not all associated with fossil fuels, i.e. nuclear).
So accepting that the object of the exercise is raising CCNS for cloud seeding – why the ships? Why not seed the plumes we already have? Surely we could easily raise CCNs in much greater proportions into the high atmosphere with much greater reliability using what we already have. Existing facilities would also lend themselves to testing.
Is there something which prevents this?
The mariners and engineers on the thread say that ships are a bad idea. So why not forget the ships?
OT, but related and maybe of interest to technophiles (or BS sleuths):
http://www.icar-101.com/icar/index.php
Yes, an air-car supposedly getting its lift from the same Magnus effect. Can anyone see this idea getting off the ground? (The name suggests that the sugar-daddy that they are hoping to get funding from in this case isn’t Bill Gates but rather Steve Jobs.)
Willis Eschenbach :
May 12, 2010 at 11:59 pm
anna v says:
May 13, 2010 at 8:29 am
anna, three times now I’ve said “show me the numbers”. If you think my numbers are wrong, point out where they are wrong.
And once again, you have replied with handwaving, telling me “catamarans work and ships work” and the like.
Dearest anna, I am a sailor. I have sailed boats large and small around the planet. Do you think I don’t know that catamarans work? What I’m saying is that the design that they are proposing won’t work. I can tell you that Flettner rotors are not more efficient than wind turbines, that’s why we use wind turbines. I have given you the calculations showing that you need thousands of square metres of intercept area for a wind turbine to develop 200 kW, so obviously you will need more intercept area for Flettner rotors to develop 200 kW. And they are claiming it can be done with 175 square metres. I thought you were a scientist. RUN THE NUMBERS!
You reply by telling me that you read somewhere that Flettner rotors are “ten times more efficient than sails”. Well, I doubt that, but even so, so what? They are not more efficient than wind turbines, and you’d need 5,500 square metres of those to get the power that they claim to need.
Next, you say “The seeding effect works experimentally, when one sees the clouds over the ships routes. I do not think megajoules are being wasted in the exhaust of the ships engines.” I don’t think megajoules are being wasted either. I’m saying that their proposed power system won’t create the power that THEY SAY THEY WILL NEED. Not what I say they’ll need. The 200 kW that they say is required.
Next, you say “the effect will be simulated by centrifugal pumps with small energy needs.” anna, that is handwaving. If you know that the energy needs will be small, give us the calculations. Show us the power requirements. Expose your numbers, you know, the data that you are using to make your claim. What figures have convinced you that the energy needs will be “small”, and how small will they be?
Finally you claim that if I
I am against this because THE NUMBERS DON’T WORK OUT. Not because it is finicky. Not because there are small thigamajigs. I’m a seaman and a commercial fisherman, I know more about making small finicky things work in the middle of the ocean than you can imagine. That’s not the problem with this idea. The problem is that they have not done their homework. They have done what you have done, waved their hands and said “well, it looks like three Flettner rotors will power the whole thing”. Sounds nice, until you do the numbers and you realize that it will take about SEVENTY FIVE Flettner rotors to power the whole thing.
Their numbers are wrong, not just a bit wrong, but wrong by orders of magnitude. To me, that’s a very, very bad sign.
Now, you may think I’m wrong about the numbers. I have been wrong before, there’s more ways to do them wrong than to do them right. But you will not convince me that they are wrong by saying that Flettner rotors are more efficient than sails and that they’ll only need small centrifugal pumps and going on about finicky thingamajigs.
anna, have you ever tried to use a trailing propellor to pull energy from a wind powered ship in the ocean? Because I have, and I can assure you, it is neither simple nor easy. The problem is that to get much power from the wind, you need to intercept a very large area … which makes your ship vulnerable if you can’t reduce that large area when a storm hits. That’s one of the main reasons that Flettner rotors are not used. Look at the ship in the head post, and imagine what a strong wind would do to it … and even with that huge, topheavy design there is nowhere near enough rotor area to get the energy that THEY, not I but they, say that they need.
So again, let me make my plea. I put my numbers out here to be examined and shot down. If you think I’m wrong, show me the numbers.
PS – Oh, yeah, you say:
If you think that because one technology can be automated all technologies can be automated, you haven’t thought things through. Automating an airplane for a few hours at a time in the clean, sterile, and highly predictable airborne environment is a very different problem from automating a wind-driven ship for months in the dirty, rough, unpredictable marine environment. When’s the last time you heard of an airplane getting a piece of abandoned net wrapped up in the propellors? How often do you think it will happen to the lovely underwater turbines of the ship design that these folks propose?
Egads, save me from dreamers who have spent too much time in their ivory towers and behind their computers, and spent far too little time cursing and struggling under a boat to get a piece of old rope unwrapped from a propellor shaft … I’d be overjoyed if someone could automate that, but despite robot drones, it hasn’t happened yet and won’t for a long time.
Willis Eschenbach says (May 13, 2010 at 12:19 am): “I’ve been thinking about numbers. For me, when I look at numbers in a variety of fields, I often have an innate sense of whether they are of the right order of magnitude, or whether they are obviously way out of line.
After much thought about this ability, my conclusion is that I can do that because I didn’t have a calculator as a kid. I had a slide rule.”
Oh man, that takes me back to my college days. Being a bio major, I never got as good with a ‘rule as my engineering friends, and never used more than a fraction of its capabilities. Fortunately in grad school the handheld electronic calculator came along to put me out of my misery. 🙂
The order-of-magnitude “reality check” is still good practice, though. It’a a good way to catch the GI before you get the GO.
anna v says (May 13, 2010 at 8:29 am): “And as Julian Flood also says, the problem of AGW is political, and this is a cheap face saving idea for politicians to latch onto. You are doing a disservice to the community of thinking people by dismissing/ridiculing this out of hand so lightly.”
It would be an even bigger disservice to put the CAGW dogma on life support. It needs to be killed dead, and buried; the sooner, the better. Then “thinking people” like Dr. Salter can apply their talents to real problems.
The technical term is UAV, unmanned aerial vehicle or RPV, remotely piloted vehicle.
Although technically these are drones they can fly on their own and they are still controlled by human operators on the ground. And that is a good thing because some of those UAV are actually called UCAV wich stands for Unmanned Combat Aerial Vehicle. For now its not a good idea, the idea that M$-UCAVSoftware 1.0 (SP2) might still have some bugs wich might result a Predator launching its hellfires prematurely.
But controlling the seed ships by AI or a controller on the shore is only a minor detail in this plan.
Am I missing something or does the original paper contain some very bad mistakes. As an engineer, this sure looks like some very high and mighty ivory tower scientific theorizing bull, where the basic numbers, something we down-low-in-he-dirt engineers worry about, are not adding up at all!!
some extracts from the original paper
http://rsta.royalsocietypublishing.org/content/366/1882/3989.full
“Abstract
The vessels will drag turbines resembling oversized propellers through the water to provide the means for generating electrical energy. Some will be used for rotor spin, but most will be used to create spray by pumping 30 kg s−1 of carefully filtered water through banks of filters…”
So here they say 30kg/s = 108 m3/h
“5. Spray generation.
Each rotor has a Grundfoss down-hole pump that feeds 17 m3 s−1 to a bank of eight filters with blister valves to allow any filter to be back-flushed.”
All of a sudden the number changed to:
17 m3/s = 61200 m3/h
567 times more. ??
How much power is required for this?
“7. Project costs.
The vessels are expected to have a displacement of 300 tonnes and a plant rating of 150 kW.”
???
Pump power:
Ph = q ρ g h / (3.6 106)
where
Ph = power (kW)
q = flow capacity (m3/h)
ρ = density of fluid (kg/m3)
g = gravity (9.81 m/s2)
h = differential head (m)
Ph = 61200*1030*9.81*30 / 3.6*10^6
Ph = 5153 kW = 5 MW!!!
And another issue:
“5. Spray generation.
A trash-grid made from titanium mesh will prevent jelly fish and plastic bags from jamming the pump. If it is fed with a current of 90 amps, it can also produce 2 ppm electrolytic chlorine to prevent biological growths.”
what cleans the trash-grid? What removes the plastic bags, jelly fish, regular fish, crabs, seals and dolphins from the rack, in order to prevent the pump from cavitating and failing?
But these are of course just details..
Cloud seeding is not a proven technology. Else we would have had these installed in the Southwest US during the drought of the early 2000s.
Cloud seeding works if you have clouds that are “seedable” to begin with. In China, clouds are intercepted by silver iodide and sulfide nanoparticle sprayers to prematurely unburden the water load before it does so later on, say on the windward of the next mountain range downfield.
In the 1930-40s dust bowl, there was a famous cloud seeder, I forget his name. He would wait until the spring or summer season, best for thunderstorms. Then he would wait in the town, building up the apprehension and expectation of the townspeople. After a week or a day, when he would see a cumulus cloud formation that in his experience would produce rain, he would take off in his biplane. Attached to the wings were pyrotechnic “sparklers” that would make a lot of noise and smoke. He would ride up into the cloud and light the sparklers. A few times he would succeed, and his legend and desirability grew. He got very rich, and could produce first-hand testimony that he was a rain maker, and he did just that.
I’m sure his brother was selling opium elixir as a cure-all for rheumatism, sunstroke and varicose veins!
Summary: You have to have rain clouds to make it rain. If you don’t, it will rain anyway, later.
One quick other point: if you have sufficient wind to putatively power this rotor, this Dr. Seuss machine, then the wind slightly above will be very brisk and knock down your plume back into the sea. If the wind is quiet enough to enable the plume to rise, by definition you have lost the wind power to drive the contraption.
All this discussion of nautical matters reminds me of a scene when Edmind Blackadder hired a boat from Captain Rum. Enjoy:
I wish I could find it, but there is yet another scene where Blackadder refers to the crew. Captain Rum replies, “Ahhh! There are two schools of thought when it comes to crews …”
Stephen Salter, many thanks for your reply. You say:
May 13, 2010 at 9:45 am
That doesn’t touch the real problem. The issue is that the size and number of Flettner rotors you propose is way too small to deliver the 200 kW you say you will need to run the cloudship. Please show us your calculations to support your claim that three 20 metre x 2.4 metre Flettner rotors will put out anywhere near that amount of power.
Also, I don’t see how you can say that “But quickly, the power needed to spin Flettner rotors is between 5 and 10% of that needed to get the same thrust from a propeller.” If the wind is blowing say at 0.1 knots, obviously the power to spin the rotors is much, much larger than the power needed to get the same (near zero) thrust from a propellor. Your statement is meaningless without some specification of wind speed.
I find this claim curious. You say that the:
What is the “best size for nucleation”, how do you know that is the “best size”, and what evidence do you have that natural processes are lacking in that size?
I don’t understand this. You are talking about the change in lift, not the change in overturning force. Lift indeed goes up linearly with wind speed. But the spinning cylinder merely separates the wind force into a lift component and a drag component. It cannot reduce the total force of the wind acting on the cylinder. So if you get a strong head wind or tail wind on your spinning cylinder, the heeling forces will be huge … how will the boat deal with that?
No, the existence of unmanned planes over Afghanistan means absolutely nothing about unmanned sailing ships. That’s a logical fallacy. As a long-time sailor, I can assure you that there are a host of problems sailing ships face that are never encountered by drones over Afghanistan. See my answer to anna just above.
And once again, you have provided no numbers regarding your claims. Yes, Flettner’s ship may have had less windage than the sailing ships of his time, but the sailing ships of his time were square riggers with huge windage, so like the song says, “That don’t impress me much.” And where is the data for that claim?
Let me be clear. What is needed to support your claims are calculations. Not apocryphal statements about ships that are no longer afloat. We need something that says “A Flettner rotor operating in a 15 knot wind puts out X watts per square metre of cross sectional area.” I have estimated an upper bound on this from wind turbine data. It shows that your three rotors are woefully inadequate. It show that you will need at least 75 Flettner rotors that are 20 metres by 2.4 metres to produce 200 kW average power. I have given the source of those numbers.
Now, you say you need only three rotors … so show us your numbers that support that claim, and this question will be put to bed.
Also, your claim that your ship will withstand a Force 4 hurricane tells me one thing … that you have likely never been in a Force 4 hurricane …
Thanks for that information, I always thought the ducks were a brilliant idea. Why does the initial installation need to be so huge? Why can’t a 10 kW plant be built, just to see if it will work and will survive the savage seas?
I look forward to your calculations on the Flettner rotors. I’ve looked at them every way I can, and I can’t see how three rotors will produce 200 kW. I used to teach windmill construction and maintenance, and I have sailed extensively, so it is an area of great interest to me.
All the best,
w.
“Robert says:
[…]
But controlling the seed ships by AI or a controller on the shore is only a minor detail in this plan.”
Yeah, that’s what my clients always say. In the end we also need some small box with which the user can control the entire installation, that can’t be that complicated, no? After all, it’s a fleet of huge ship, and the control stuff is only a few chips and maybe an Internet connection, right? Oh yeah, and some software.
Fast, cheap, reliable. Pick any 2.
Julian Flood says:
May 13, 2010 at 3:10 am
No, the ships don’t have megapumps. But the CCNs from the ships are at a temperature of 1,000 degrees F or so, so they will rise thermally up to the upper levels. Are you proposing to heat the fine mist to that temperature?
Can CCNs increase clouds? Sure, lots of things are possible … if the conditions are exactly right. Which is hardly any of the time. How do I know that? Because it is very rare to see a ship sporting a “contrail” of cloud. The vast majority of the time, they don’t sport a contrail of any kind.
In addition, if you look at the ship tracks in the NASA photos, you see clouds in every one of the photos as well. Why? Because when conditions are right for ship tracks, they are right for clouds. As a result, we’re not going from clear to cloudy. We’re going from cloudy to slightly cloudier, with only a small change in the overall albedo. Here’s what NASA says about ships tracks:
So unless the air is “super-saturated”, all of the CCNs in the world won’t make any difference at all …
” But the CCNs from the ships are at a temperature of 1,000 degrees F or so, so they will rise thermally up to the upper levels. Are you proposing to heat the fine mist to that temperature?”
Willis, that is ridiculous. Are you seriously suggesting that the exhaust from a ship’s funnel (I bet they call them something much more hip like ‘stack’ nowadays) is at 1000 degrees? Next time you drive a diesel car, get out with the engine running and put your hand in the outflow from the exhaust. Note the lack of flesh turning black and crispy? That’s because it’s rather cool. Same with ships.
However, let that be. Think of the natural system. When a wave breaks it makes CCNs. Unless the conditions are right those CCNs are little salt particles, dry little grains which weigh damn-all. They float in the air. This is within the area known as the boundary layer, where the wind (which has made the waves in the frst place) creates up and down draughts and mixes the CCNs up to the top of the layer which is generally about 2 to 3000 ft. Remember the lapse rate, 3 degrees per thousand feet. It gets cooler the further up. Relative humidity rises, a threshold is passed and the salt particle attracts water. A droplet forms. Note the lack of stacks, heat, pumps, human intervention. This is the way strato-cumulus clouds form. They do not, I repeat, do not need aids. It’s the way the boundary layer works.
“In addition, if you look at the ship tracks in the NASA photos, you see clouds in every one of the photos as well. Why? Because when conditions are right for ship tracks, they are right for clouds.”
Except that large patches, ‘right for clouds’ don’t actually have cloudiness. Why? Because they lack CCNs, they are ready to be triggered and, when a passing ship pushes out a tiny quantity of particles, a cloud forms. Not, you will note, at sea level where the particles are emitted (have you ever watched the exhaust from a funnel blow away across the sea I wonder, conspicuously failing to leap skywards as their red-hot temperature demands, or sniffed the effluvium of a passing destroyer a mile or more away?) but at the level required by the simple physics of droplet formation on a deliquescent particle at that temperature and humidity. Ship tracks neatly illustrate the way the natural processes mix CCNs, making the cloud at the level required by the physics. However, I’m ready to be educated. Perhaps a reader conversant with ship’s exhausts will chip in. Perhaps someone will even have pictures of diesel smoke rolling over the sea surface.
“As a result, we’re not going from clear to cloudy. We’re going from cloudy to slightly cloudier, with only a small change in the overall albedo.”
Yes! That’s why Professor Salter has told us that he needs only 1% change in reflectivity, not that he needs to make more clouds, new clouds, he just increases the albedo of local clouds by giving them more CCNs which increases their albedo by increasing the number of droplets. More CCNs = more droplets = smaller droplets = whiter cloud = more cooling. A cloud rich in CCNs is a whiter cloud. An ocean producing fewer CCNs for any reason will warm as the albedo of its cloud blanket falls. Fewer CCNs = bigger droplets = lower albedo.
“So unless the air is “super-saturated”, all of the CCNs in the world won’t make any difference at all …”
Except that the air inside the cloud is saturated — that’s why it’s a cloud — and the addition of more CCNs will spread the water around into smaller droplets. That’s how Slater’s cloud ships work.
I bow to your experience of ships and stability, I know nothing about such things. I’ve been on a few ships, notably HMS Newcastle in the cold seas off the Falklands. If God had meant us to travel over the sea by boat he would not have invented Buccaneers. Or submarines.
JF
Willis
At least you should add something to show that your conclusion in the main post above,
what we have here is a non-viable non-solution to a non-problem. I wouldn’t want to comment either, especially since this non-solution will burn about 27 billion litres (about 7 billion US gallons) of fuel per year to supposedly “solve” the problem supposedly caused by CO2 from burning fuel …
is a back of the envelope calculation of a different problem than the one proposed by Slater et al.
From the thread it is clear that
1)there is no crew
2)mainly wind will be used for energy
3)the natural circulation of the atmospheric content will be utilized so there is no need to lift thousands of tons to 3000 feet artificially.
so all the fuel back of the envelope calculations in the post are irrelevant to the problem.
You are asking me for numbers, and I do not have access to publications that would help me get numbers, even if I had the expertise to use them, which I do not. My searches end up behind pay walls. I can hand wave ideas, I can give links but not numbers calculated by me.
I can do analogue well though.
To dismiss out of hand that robots can work at sea is really not very wise. Of course there will be humans controlling the robots to deal with all that could possibly happen and a system of intervention, but robot systems do work and the modern wars show it.
W. – I was awaiting a numerical response from the advocates of this proposal before commenting, but none has been forthcoming. I don’t know why, as
actual numerical data
on the performance of Flettner rotors is not hard to find.
The reference suggests you need to be careful about using the actual cross section of a Flettner rotor in calculations as if it were the cross section of a traditional sail or wing. Flettner rotors don’t work via the same mechanism and apparently have an effective cross section approximately seven times their actual cross section.
While I haven’t crunched the numbers this suggests that your calculation on the power produced is probably off by a factor of seven. Not enough to redeem the proposal though.
As to why Flettner rotors are not used in windmills to replace windmill arms, a brief consideration of the torque involved in rotating a spinning Flettner rotor about one end suggests the most likely reason. The strain on the bearings would be immense.
Ian H
thanks for the link:
http://www.rexresearch.com/flettner/flettner.htm
The only actual numbers are that the assisting motor is of 10 horsepower
and the claim that the output of the rotor is 1000 horse power.
If one horsepower is 750 watts, 1000 is 750.000watts
which gives that machine designed in 1926 almost a megawat.
Another reference speaks of twice that .
BUT it is just numbers and I do not see how they are calculated so am not further ahead.
,
Well, lets get some numbers.
The energy of movement is E=mv^2/2
The density of air is about 1.2 kg per cubic meter at 20 degree centigrade (lower if warmer, higher if colder, we’re in the tropics, remember)
The ships have three rotors, each 20 x 2.4 meters.
Lets assume that the rotors catch 100% of the wind energy (which is of course quite impossible). Since air has some (slight) viscosity let’s also assume (generously) that the effective area of each rotor is actually 20 x 3 meters. The total catchment area of the three rotors is then 3 x 20 x 3 = 180 m^2 (if wind is on the beam, that is, otherwise the rotors will be blocking each other)
The whole system is supposed to work in a wind strength of 8 m/s. We then get:
1,2 x (8)^2 / 2 = 38,4 Ws per cubic meter of air. 8 cubic meter of air passing through each square meter of catchment area per second gives 8 x 38,4 = 307,2 W.
3 x 20 x 3 = 180 square meters of catchment area
Total energy 180 x 0.3072 = about 55 kW
And this, remember, under wildly optimistic assumptions. And this is supposed to drive a 300 ton vessel through the water fast enough to power turbines to generate 150 kW?
tty
I do not think this calculation works for the rotors.
from the link:
http://www.rexresearch.com/flettner/flettner.htm
On the other side of the cylinder, the opposite is true. The velocity of the wind combines with the velocity of the air layers next the cylinders, resulting in a decrease in pressure. On one side of the cylinder there is an increase of pressure, on the opposite side a decrease, so that there results a strong force from the stronger to the weaker pressure. This causes the ship to move forward.
The magnitude of this effect, Mr Akimoff says, may be computed by multiplying the following quantities: the density of the air, the velocity of the wind, the peripheral or surface velocity of each cylinder, the circumference of each cylinder, and the height of each cylinder. In the case of the Buckau, considering the velocity of the wind at 40 feet/second, the forward thrust due to the moving cylinder would be 12,000 pounds. Actually, this would be reduced, on account of various losses, to the extent of 10 percent.
To play with a Flettner rotor simulator, the NASA has a nice Java applet:
http://www.grc.nasa.gov/WWW/K-12/airplane/cyl.html
DirkH says:
May 14, 2010 at 4:51 am
Thanks.
Nasa, hm? Imperial units!
No wonder they made a mistake in units and crashed a take off.
feet per second and slugs per cu.
They call radius b for goodness sake.
@ur momisugly anna v.
You keep saying the same things in response to Willis’ questions for numbers.
And now you added the statement that you do not have them.
In my two previous posts I used the numbers in the original paper, and found some big mistakes. On top of that I showed that even without pumping the water to 3000 ft, you’ll need approx. 5 MW to force that amount of water through the filters and “atomizing mesh”. Also I showed that seawater systems need extreme measures to prevent clogging and failure.
Are you just sticking your head in the sand?
Why don’t you take everybody’s advice and do some homework, you are starting to sound silly, like a high and mighty scientist without a feel for reality.
anna v says (May 13, 2010 at 9:22 pm): “I can do analogue well though.
To dismiss out of hand that robots can work at sea is really not very wise. Of course there will be humans controlling the robots to deal with all that could possibly happen and a system of intervention, but robot systems do work and the modern wars show it.”
Exactly. The US Navy, for example, routinely operates several hundred remotely controlled Flettner ships in the tropical pacific 24×7 for months at a time…oh, wait.
BTW, another word for “analogy” is “model”. YMMV.
Lance says:
May 13, 2010 at 4:22 am
you say
So each pump does 33.000 m3/h, or approx 9.500 liters/s (same as these ships are supposed to do).
To bring this enormous amount of water up to a pressure of about 2.5 bar abs., it requires an electromotor of approx 1,6 MW!
in the reference you also give it says
http://rsta.royalsocietypublishing.org/content/366/1882/3989.full
The vessels will drag turbines resembling oversized propellers through the water to provide the means for generating electrical energy. Some will be used for rotor spin, but most will be used to create spray by pumping 30 kg s−1 of carefully filtered water through banks of filters and then to micro-nozzles with piezoelectric excitation to vary drop diameter.
Where did you get the 9500liters/second?
anna v:
You are mixing things up here. What is being mentioned in your citation is force, not energy. There is nothing magical about a Flettner rotor, it works by deflecting the airstream, just like an aircraft wing. In theory a wing can develop any amount of lift, if it just moves fast enough with a suitable incidence. In practice this does not work, you do not have unlimited power, the mechanical strength of the wing is limited and the airflow over the wing will break down at some point.
The same constraints apply to a Flettner rotor. In the case we are discussing the three rotors will (theoretically) develop a force of about 3300 Newton for each rps (rotation per second) in the nominal case of zero altitude, 20 degrees centigrade and 8 m/s wind. In practice it will be less, since airflow is never ideal. How much less is impossible to say without a full-scale trial (no, you can’t simulate a thing like this in a wind tunnel, there is no way to simulate reynolds number, nor the deterioration of surface smoothness under operational conditions).
Unfortunately there does not seem to be any data on what rotation speed is planned in the paper, but I should point out that friction will go up with the square of the rotational speed, while the force on the rotor is only proportional to the speed, so increasing the speed of rotation is ultimately self defeating, even if there were no mechanical constraints.