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Massive Solar Tower Planned For Arizona
inkscapee writes "It's simple, clean, low-maintenance, and cost-effective: using hot air on a large scale to generate electricity. No, this not a plan to use Congress to generate power, though that would certainly be an endless supply — EnviroMission will use air rising up a tall tower to generate 200 megawatts of electricity. The concept is simple: a giant greenhouse at the base of the tower warms the air. The warmed air rises through the tower and turns turbines, which generate electricity. The taller the tower, the faster the air moves, which increases power output. This structure will be a monster at over 2600 feet tall. It works in all weather, and if there is a feasible water source, food could be grown in the greenhouse."
But too bad - the greenhouse effect is a myth, as we all know.
using hot air on a large scale to generate electricity.
Hence the "DC" in Washington DC.
The mammoth 800-plus meter (2625 ft) tall tower will instantly become one of the world's tallest buildings.
Compensating for something there, Arizona?
"None can love freedom heartily, but good men; the rest love not freedom, but license." --John Milton
This is, by far, the kind of tech we need to be investing in, preferably starting a decade ago. Genuine renewable, reliable power - are deserts hot? Yes? Let's make power from it! It'll be terribly uneconomical at first, of course, but it can improve given time. And it's worth trying out. It might not pan out, but it's sure as hell a better investment then 1.1 million in legal fees trying to surpress video games or whatever other legal action is popular at the moment.
So even if it's silly, go for it, Arizona - this is a much better investment then your immigration laws. In fact, triple your budget for this.
into cooler air, higher up. I wonder what the weather will be like near that tower after it goes into operation? This could be a neat experiment!
Paranoia is a Survival Trait!
At "176-194 F", I'm not familiar with any plants that grow well.
The efficiency of a heat engine depends on the difference between input and output temperatures, so this can't be very efficient, though efficiency is less important when the input is so cheap.
I'm not sure how 2600 did this, but it is a nice hack!
No, this not (sic) a plan to use Congress to generate power, though that would certainly be an endless supply
Yep, another old, tired, stupid and vacuous panning in the summary that you'd expect from a 14 year old who thinks he's massively clever. This is is what Slashdot has become.
FTA:
In the video after the jump, EnviroMission CEO Roger Davey explains the solar tower technology, the Arizona project and why he couldn't get it built at home in Australia.
Every time I start to have faith in humanity, I ruin it by driving to work between 7 and 8 am.
It's in Arizona, what do they have to lose? :-P
"When information is power, privacy is freedom" - Jah-Wren Ryel
So you are saying the tower is constructed only by increasing carbon dioxide in an open chamber?
Odd, I thought it used heat trapped by passing through glass.
"There is more worth loving than we have strength to love." - Brian Jay Stanley
I would see that growing food would be counter productive to generating electricity. In order to make maximum use of the facility, you want as much energy as you can to heat the air. And you want an air path with as little turbulence as possible to facilitate flow through the tower. Plants in the greenhouse would a) consume some of the captured solar energy, lowering the amount of heat imparted to the air and; b) provide obstructions to the flow of air. Certainly you can mitigate some of these effects. However, the constant influx of fresh air would take away a lot of the captured heat, which is the point of having a greenhouse to grow plants.
All of that aside, I wonder about the necessity of a greenhouse keeping plants warm in Arizona. I don't think warmth is as much a problem in Arizona as it is elsewhere but that's just me.
This is in the middle of the desert, so no chance of hurricanes there. Also, its just a hollow tube, you could easily reinforce it to withstand high winds like that. Because is is hollow you have the option of putting louvers all over the sides. If a storm pops up, open them all and let the wind pass through the tower, problem solved.
We're talking Arizona. Not much threat of hurricanes there.
This is a ridiculous idea. The only structure that is taller than 2600 ft is the Burj Khalifa (Burj Dubai), which is 2717 ft.
http://en.wikipedia.org/wiki/List_of_tallest_structures_in_the_world
The idea that we would build the 2nd tallest structure in the world for 200 MW is ridiculous. This doesn't even come CLOSE to being a top producer of energy per power plant. The top 10 power plants in the world all produce more than 6000 MW. Even the largest biofuel, geothermal and tidal plants currently exceed 200MW.
http://en.wikipedia.org/wiki/List_of_largest_power_stations_in_the_world
-molo
Using your sig line to advertise for friends is lame.
My initial question would be what happens when a hurricane lands near a 2600 foot tower perched on a giant greenhouse? Somehow the mirrors (concentrators) and water/oil tank configuration of solar power seems like a more resilient structure, if only for the fact that the mirrors are smaller and closer to the ground and you dont need a massively tall tower.
I rather doubt that Arizona has seen a hurricane in quite some time.
Faster! Faster! Faster would be better!
I wouldn't be too worried about a hurricane in the middle of a desert.
Time to offend someone
I don't think hurricanes are much of a concern in Arizona.
"When information is power, privacy is freedom" - Jah-Wren Ryel
not many hurricanes in Arizona, but seeing as this is as tall as the tallest building in the world, the Burj Khalifa in Dubai, I can't seeing this being economical at only 200 MW.
I like that idea, but how would you cool the air at the top?
"Some books contain the machinery required to create and sustain universes."-Tycho
When was the last time a hurricane hit Arizona?
I really don't know which type of solar plant is better, I have looked strongly at solar concentrators with a heat reservoir and they are an excellent option, but I don't know that much about these passive solar towers.
Yellowstone has some bacteria that grow at those temperatures, perhaps they could be molded into colorful bacon strips.
"There is more worth loving than we have strength to love." - Brian Jay Stanley
Hurricanes don't end up in Arizona.
What does happen is that a Hurrican travels up the Colorado River and loses steam as it comes inland.
By the time it reaches Arizona, the hurricane is, at most, a tropical storm with gusty winds that are manageable.
[Fuck Beta]
o0t!
Hurricanes hit coastal area's and sometimes a little inland before they die, but there is no way in hell that Arizona is going to be hit by a hurricane.
For a hurricane to hit Arizona it would have to traverse the gulf of Mexico, pass over both Texas and New Mexico. Moving across land seriously diminishes a hurricanes strength, there is no way a hurricane would even reach New Mexico let alone Arizona.
Don't know something? Look it up. Still don't know? Then ask.
One of the engineer on this project is obviously an Atari fan.
hmm...looks a lot like something I once saw on Star Trek TNG (the pilot episode, no less): http://stavatars.net/images/locations/planets/planet_farpoint_station02.jpg
Anybody with knowledge on the topic: is there a way to add a Thermocouple element to this to increase the potential for power generation? Or is that an insanely expensive proposition or just a flat out bad idea?
1 (short ton / firkin) = 89.1432354 slugs / keg
It looks like the base of the buildings in The Jetsons... sounds to me like we will soon be selling real estate at the top of these towers... all the power for the building will be supplied by its own structure...
Dude, this is Arizona. In the middle of a desert. How, pray tell, is a hurricane going to hit there?
General Relativity: Space-time tells matter where to go; Matter tells space-time what shape to be.
The idea is interesting, but it seems to me that a substantial portion of the solar energy is going towards gravitational potential energy - that is, lifting tons of air mass hundreds of feet in the air.
At some point, that air mass cools off, the air will want to drop back down towards the earth because of gravity. Seems like, in addition to generating 200MW on the 'exhaust' stack, they could build a second "cool air return" stack that generated power from the force of gravity pulling the cooled air back down to ground level?
-1 parent. The exhaust air at the top of the tower is going to keep rising because it will still be hotter than the ambient air. The cold air that falls to offset the rising mass is called the atmosphere. It's big, it's going to be moving slower than the air you just used to spin a turbine, and it's not cost effective to try to make electricity from it until it enters the greenhouse, gets heated, and funnels into the turbines that are already in the design (the one place where air is moving fast in the whole design.
For this specific case: not many hurricanes in Arizona, nor in most every desert.
More generally: site selection and engineering for the weather are surely taken into account before they break ground. The tower is freestanding and attached to the ground - the greenhouse is built around it, not the other way around. Even if the company glosses over stability in inclement weather, it should be caught in the permitting process. And even if it isn't accounted for during permitting, you can bet the insurers and underwriters will want good answers. Even so, this probably isn't ideal technology for, say, coastal Florida.
Upper troposphere? The height of this is nothing compared to any atmospheric layers. I'd be surprised if any climate effects will be measurable outside of the immediate vicinity.
"When information is power, privacy is freedom" - Jah-Wren Ryel
Would this work in the heat islands created by cities?
Impetuous! Homeric!
They aren't "lifting tons of air mass" against gravity. Gravity pushing down on the surrounding air is what is pushing the air up in the first place. This tower is a way to focus that downward push of cool air onto a narrow tube of hot air that then floats up and runs the turbines. This isn't any different than boiling small amounts of water at the bottom of a lake. The bubbles will rise quickly and that energy could be harnessed, but it would be pretty useless to try and harness the energy of the resulting water vapour eventually drifting back to the bottom of the lake.
Tornados are also extremely rare in that part of the US. Here is a map of tornado occurrence: http://en.wikipedia.org/wiki/File:Tornado_Alley.gif
However, they do have haboob wind storms with wind speeds up to 30 mph and lots of flying sand. http://en.wikipedia.org/wiki/Haboob I guess these and thunderstorms are the most extreme weather that the structure would have to survive.
I'm certain that the people planning the project are well aware of the extreme weather conditions in Arizona. Why are you raising this queston? It implies that you have an insight that they have overlooked, which is extremely unlikely.
Why is Snark Required?
Ya'll got taken for a ride.
Stock opened at .66 this morning, it's now at .72 cents. Up 9.09%
Ya'll helped someone make a nice trade..
Thanks guys!
I know this is in a desert, but it will rain on rare occasions; what will they do with the water that falls on the structure? I imagine it would not be worth while to collect it and transport it somewhere, since it will be so rare. I feel like they probably have considered this, and I just want to know what decision they came to. Put it all in a big gutter, feed it into a huge sump (or a lot of little ones), or what? Also, what about dust buildup - will it get cleared by wind (like the Mars rovers' solar panels) or will someone have to go up there with a giant squeegee to clean it off every now and then? Again, I bet they have thought of it, and I am curious about what ideas they came up with. Maybe they only clean it when it rains? Maybe every time they do clean it, it rains the next day? Who knows?
From the images in the article it appear that the radius of the greenhouse will be greater than the height of the tower. How can that possibly be cost effective?
In 2005 EnviroMission said that the first solar tower would be up and running before year 2008 in Australia. That never happened.
Now in 2011 they say that it will be ready at the start of 2015 in Arizona. I hope they succeed this time.
My initial question would be what happens when a hurricane lands near a 2600 foot tower perched on a giant greenhouse?
If there are hurricanes reaching Arizona, I think there are far more things to worry about then what happens to some 2600 foot tower in the middle of the desert.
But it could happen! See, you smarty-pants engineers calculate what could happen based on what happens around Arizona in the past, but what happens if the San Andreas fault lets go and most of California sinks into the ocean? Then Arizona ends up right next to the coast and could be affected by hurricanes! What then, Mr. Smarty Pants?!
(The above is sarcasm, by the way)
Seriously, though, I assume the GP meant "tornado" as hurricanes tend not to "land," though they do make land-fall. Tornados "touch down" which is somewhat similar to landing. Of course, the answer is that you reinforce and weigh down the tube so that the tornado won't pick it up, carry it hundreds of miles, and drop it on a church.
Just Arizona itself. I consider that a win/win ;-)
People in cars cause accidents....accidents in cars cause people
It's not habitable. With a payback period of 11 years, it's doing pretty well, particularly for a renewable energy plant.
to generate electricity, but isn't a major hurtle for projects like this one the distance from where the electricity will be consumed? They're confining this to the desert, because of the daytime temps, but most power is being used on either coast, thousands of miles away.
It's just a hollow tube with some minor reinforcement. Hell you can use guide wires like they do for radio towers. There's very little cost compared to an occupied office building/residence like the Dubai tower.
People in cars cause accidents....accidents in cars cause people
Who would tend the crops? They're kicking all the migrant workers out.
Because the dubai tower is a hotel with needs lots and lots of cooling and other luxeries compares with a hollow tube that generates power not consume it and needs to compete with other powerplants that need fuel or hydro plants which needs enormous lakes...
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You may solo them, I prefer them in a group.
To put things in perspective...this thing costs less than a single B-2 bomber, and about the same as a few 747s or a large cruise ship. Which is more beneficial?
You know nothing.
When the Big One comes, if it is San Andrea's Fault, the continental US is going to slide into the Atlantic!
"and if there is a feasible water source, food could be grown in the greenhouse." Uh, this is the Arizona desert we're talking about here. Any living thing inside a greenhouse outside of December and January is going to be baked to a crisp. :)
Nah they'll just pump it in with a 200MW set of pumps oh wait...
Seven puppies were harmed during the making of this post.
I guess you think Mormon Lake is just a mirage?
Because hurricanes are powered by heat differentials. OK, you'd need some kind of tower pumping hot air a few thousand feet upward, but it couid happen.
(I jest, I jest!)
Please consider this account deleted, I just can't be bothered with the spam anymore.
Actually, that effect you mention is the mechanism by which they *capture* the solar energy. Of course they don't capture *all* that energy, but that's not the point. The point is the energy you take out as a function of investment and operational costs. The tower component is bound to be pretty expensive, but the system has no moving parts other than the turbines and it can be scaled up by building out over cheap land.
It's the NPV of all the inputs per kw/h that matters, and if the figures come out competitive it doesn't matter if the system is not all that thermodynamically efficient.
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Phoenix is one of the largest cities in the USA.
I'm kind of picturing something like the St. Louis arch, maybe? The 'hot' side has the air rise, the top acts as a heat exchanger to cool the air, then it falls down the other side of the arch (which also is a heat exchanger and continues to cool the air further as it falls).
I dunno, maybe it wouldn't work for some reason, but it just seems like that air has weight, and you should be able to capture some additional energy that is invested in it from its increase in elevation.
I guess these and thunderstorms are the most extreme weather that the structure would have to survive.
Along with whatever microweather you generate when you build a 2000+ foot tower in the desert to pump hot air into the atmosphere.
the preceding comment is my own and in no way reflects the opinion of the Joint Chiefs of Staff
The adiabatic effect will take care of this. Although I'm not sure how much cooling will happen in 2600 feet, which is large in the context artificial structures but not so much in the context of mountains where the adiabatic cooling caused by orographic lift results in snow. On the other hand, considering the initial temperature of the air mass at the bottom of the structure (due to the greenhouse), the effect may be more "effective".
Problem is only solved if the winds are running at an angle exactly parallel to the louvers. Otherwise, they serve as baffles and apply leverage to the tower while also adding turbulence. And winds change angle and velocity constantly. You'd likely be better off simply designing the tower to be smooth, circular, and very strong.
I've fallen off your lawn, and I can't get up.
You're right. Now I think about it more, you're right. The reason the air goes up the tower instead out the bottom/side of the greenhouse/dome is that the surrounding cooler air is heavier/denser, and so as the internal pressure of the air increases as it warms, it's easier for it to go up the tower than to squeeze out against that dense air.
So, in a way, a portion of the energy being captured by the tower *is* the gravitational potential energy of the surrounding atmosphere 'falling' towards the ground outside the dome.
I love how simplistic the article is when it comes to cold air at the top of the chimney etc. A tall chimney works better because air is colder at altitude? In that case, why doesn't all air rise all the time, leaving a vacuum on the ground? Oh, wait a minute, rising air cools while it's rising... So much for that theory about how the chimney works, then.
I'm sure there's a much better explanation, for example (I'm guessing) that the temperature gradient above the desert during the day is stronger than the cooling gradient of rising air. Or something like that, I'm actually curious. Oh, and how does that chimney work when there's a temperature inversion at night and in the early morning? I'm not saying the designers haven't thought of that, just that the article is a bit oversimplified as usual.
on whether or not there are any contractors for these planes in your district.
The Burj Khalifa cost some $1.5B to construct. Assuming they can only average half of that 200MW power output, and a fairly low power selling price of $0.10/kWh, you're looking at $240K in power produced per day, or some $87M per year. Now lets assume they're using some form of rugged polycarbonate as the collector and tower. They'll probably end up with a modest maintenance cost to do upkeep on the turbines, and check over the metal framework for the tower, say $15M per year. That's payback in just 21 years, and they're expecting an 80yr lifetime out of the tower.
Now you have to realize that this is not a solid structure like Burj Khalifa. It does not have to carry hundreds of floors, with walls, furniture, elevators, and be rated for occupancy. It doesn't even have to be free standing, and can be stabilized by guy wires. The 2kft tall KVLT TV mast cost only $500k to build in 1963, which comes out to $3.5M in today's money. It's not going to cost nearly as much as you think.
My guess is that any weather you change will be a few miles to the East simply due to prevailing winds.
Every time I start to have faith in humanity, I ruin it by driving to work between 7 and 8 am.
The Burj Khalifa has some features that makes it a good deal more expensive than this structure. Floors for one :-)
The temperature at the bottom of the tower is not the ambient ground temperature (40C), but has been heated by the greenhouse to 90C. That is a much larger temperature gradient than normal atmosphere. Plus, during the day the ground under the greenhouse is being heated considerably, so at night there is still a very large gradient.
Could be an interesting attraction. If the airspace isn't too restricted, sailplane pilots might have fun with it. (From what I understand, it's already a popular form of recreational aviation in Arizona anyways.) Seems to me like that would be an easy way to get a free thermal elevator ride for an entire afternoon of gliding. No looking for thermals when you have a reliable source for one in a given spot.
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unlike an office building, a solar tower will have massive temperature swings warping the structure at every day/night transition.
Kradadoom may be being silly about hurricane's in AZ but he's more on the right track than the people tut-tutting him. Hurricane's no, monsoons yes. Monsoon storms flood, down trees and telephone poles, and rip nice, flat, airfoil like surfaces right off if they are not properly secured. Since you engineer structural strength to handle peak loads there actually is a significant wind threat.
The "requires almost no maintenance" sets off alarms bells for me. In the desert? People cite the AMARC boneyard but those planes are pre-treated and metal aircraft frames really don't require a lot of maintenance, which is not what this thing is going to be made of. Buy a car that's been sitting in sun for 5 years like I did one time and you'll discover interior plastics disintegrating to the touch and sand in everything (and was still a lemon at the low low price of $500). Tempe Town Lakes dam materials were supposed to last 30 years in the AZ sun, instead failing catastrophically in a third as much time. The desert environment can be brutal on materials.
I get it... turbine generators have really good efficiency and we've refined their use for over a century. But it seems to me that every worth-while method of power production uses them...
Solar Cells, and Lightning Rods seem to be the only methods I can think of that produce electricity without the use a turbine/generator combo but neither are viable for wide spread use. It seems to me that we'd do well to invest in methods of converting heat directly into electricity (giant Peltiers?) without the use of a turbine/generator. I would think doing so would theoretically make a number of our existing methods that much more efficient and perhaps open the door for other methods of power production.
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My understanding was that it's essentially a big chimney with a greenhouse instead of a fireplace. At that altitude I'd wager the heat dissipates pretty quickly with the wind blowing in any direction.
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A few years ago I worked at a power plant that had at one time the worlds tallest smokestack (now fifth) http://en.wikipedia.org/wiki/Mitchell_Power_Plant.
It's about half the height of the proposed tower. The smokestack had a massively wicked updraft at the ground level without any additional heat gathering skirting. There were signs on the doors into the stack warning you to not put you hands near the edges of the doors. The suction made the heavy metal doors slam shut and would take your fingers off if you weren't careful.
Overhead view: http://maps.google.com/maps?q=Cresap,+3,+Marshall,+West+Virginia+26041&hl=en&ll=39.829961,-80.815859&spn=0.010596,0.016029&sll=37.0625,-95.677068&sspn=44.52365,65.654297&geocode=FVD2XwIdi9Uu-w&t=h&z=16
When the power plant was built the answer to air pollution concerns was to build giant smoke stacks so you sent the smoke so high into the atmosphere it would be someone else's problem.
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In some respects, the tower itself acts as a hurricane.
How will this giant hollow tube and it's foundation react to being cooled and heated by 100 degrees (+/- depending on the season) every 12 hours?
With its 60% efficient design, it produces 200 MW.
Nuclear power plants are about 30% efficient, but we don't lop 700 MW off a rated output of 1 GW.
Yes, but if that was all there was to it, a short chimney would be sufficient. The air is 50 degrees hotter than ambient at ground level, so it rises. This will happen no matter whether it's a short chimney or a long one. So what's the advantage of the tall chimney? The air is cooler around the top of a tall chimney, of course, but the air rising up through the chimney will cool as well. Would the temperature difference at the top of a tall chimney be greater than at the top of a short one?
As for the night problem, I know there will still be enough heat to cause air to rise, but will the tall chimney still be an advantage when there's a temperature inversion? I would expect the tall chimney to actually reduce efficiency in that case. The outside air at the height of the tower may well be warmer than the outside air at ground level.
Relatively cheap, like this.
All of your power plants are nuclear or hydroelectric. Both cost vastly more to build and maintain.
it is remarkably good for growing baked potatoes.
It's supposed to be completely automatic, but actually you have to press this button.
or a phreaking fan
Think of the advertising and sponsorship possibilities! I am Larry Ellison, and my Oracle giant green energy penis is 30ft taller than Steve Jobs's Apple giant green energy penis! NO! I'm Zuckerburg, and even tho I don't have much geek cred, MY facebook green energy penis is 30ft taller than Larry Ellison's Oracle giant green energy penis! Really, with all the corporate cash on hand right now in some of the techs, investing in a giant green energy penis size war might make some sense.
I do not understand why they don't build this on the side of a mountain. It should work even if not vertical and would be a LOT cheaper to build as a simple plastic tube laying against a steep slope than as a km high tower.
Non-Linux Penguins ?
They're going to build a giant glass bong in the desert?!!! I guess we know what the greenhouse is really for...
the preceding comment is my own and in no way reflects the opinion of the Joint Chiefs of Staff
"In that case, why doesn't all air rise all the time, leaving a vacuum on the ground?"
I believe the answer is "convection loops". Basically, at least during the day, air near the ground *is getting warmed* and raising all over the place (some places it warms much more than others - air over blacktop will heat up quite quickly, I would think; over trees, not so much), but the reason we don't end up with a vaccuum is that there's always a supply of cooler/denser air available higher in the atmosphere, which falls down into the vaccuum created by the rising air.
Which as another poster in this thread pointed out, is probably why my idea wouldn't work too well - because in reality, the energy being extracted from the turbines is already coming from the falling air outside the thermal dome.
I believe if you contained the hot air at the top for cooling, all you would do is create equilibrium, preventing either end from working.
You stereotypers are all the same...
Line the interior with solar cells and feed some of the electricity to HVAC systems which, at that scale, could air-condition an entire city around the perimeter.
The waste heat could then be dumped back into the main stack, making it even more efficient.
At 2600 feet, the atmospheric pressure at the top is about 9 kPa less than at the bottom. This difference in air pressure also keeps the air moving upward. This is one of the primary reasons they want the chimney to be so tall. The initial speculative designs called for the chimney to be almost twice as tall as this project.
It creates a low pressure zone at the bottom, which means there will be wind converging towards it. Maybe it will increase slightly the rain precipitation, which for Arizona would be good.
I consider that an insult.
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Technically interesting and probably feasible, but a non-trivial project to take on.
Considering your Governor makes up lies about immigrants and refuses to recant them for months of being asked to produce evidence.
Considering your Governor signed a law to imprison multitudes of people...which was written by her aides who have close ties to the private prison system in Arizona.
Considering McCain's complete abdication of anything resembling integrity to get reelected.
I'd think you'd consider those more of an insult since its being done in your name...
People in cars cause accidents....accidents in cars cause people
Hot air is less dense than cold air, so it rises. A short chimney would have a small volume of low density air (inside the chimney), and then normal atmospheric pressure on top of it. By using a very tall stack, you have a very large volume of low density air. Because the pressure in the chimney is lower than outside air, more hot air rushes in from the bottom, creating a draft. The taller the chimney, the faster the draft. You need a very fast draft to spin the turbines.
Yeah, those things are certainly true. And outside of my control, unfortunately. But I still consider your statement to be an insult.
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I like this other big scale wind idea too: http://www.maglevwindturbine.com/
A 21st century issue: the irony of technologies of abundance in the hands of those still thinking in terms of scarcity.
Don't be so quick to give up. The chimney effect works just as well in reverse. If you cool the air at the top of a tall chimney, say by misting a small amount of water, it will become denser than the air beneath and "fall" down the chimney (become more dense as it does so, displacing the air at the bottom.) Apparently the amount of water needed is quite small compared to the volume of cool air displaced. And like the solar tower, the taller the chimney, the stronger the effect.
(I'm not saying it is worth either the water or the cost of a double-tower, I'm just saying it's a genuine effect.)
Science is all about firing a drunk pig out of a cannon just to see what happens.
Don't forget base jumping from the tower.
And since we now have all these tourists and adventurers, lets stick a revolving hotel at the top.
Science is all about firing a drunk pig out of a cannon just to see what happens.
These things work like big funnels - a huge area at the bottom and all the rising air channelled into a narrow space to provide a lot of moving air to run the turbines. What's on the ground wouldn't be very different from the tunnel houses tomatoes are grown in and not even all that different to what is outside.
However you're right in that it's a response about tying up land that shouldn't be needed but is to head off those "what about losing farmland" lines from those looking at an excuse to stop it. Lump it in with those that pretend that windmills tie up grazing land despite their being a total lack of giraffe ranches.
So basically you want to create a Meta-Power Plant. While I don't think they need the resonance aspect to it they could certainly add turbines to the outside to capture passing winds (they're doing this on some modern towers), solar underneath (instead of having a black painted floor even), and adding in geothermal (if feasible at that site) would be icing on the cake.
Solar cell power efficiency tends to drop off at temperature increases. Of course, if you can get them for cheap enough then it probably doesn't matter. I'd guess that building to carry the extra weight and stress of external turbines would not be a cost effective move. The goal is essentially a giant chimney, so anything that changes that is going to drive up costs quite a bit.
Indeed, I finally figured it out too. The effect has nothing to do with the air being colder at the top (bad article), only with the fact that the density of the air inside the chimney is lower, which results in a lower pressure gradient required to support its weight. The excess differential pressure imposed by the outside atmosphere, and therefore the available power, would be roughly proportional to the length of the chimney.
Things do get a bit more complicated when you add turbines at the bottom, since a turbine will reduce both the pressure and temperature of the air passing through it, but I imagine it works out fine anyway since the density does not change (much). I'm too lazy to work out the details, I imagine the designers have put enough thought into it.
My question whas rhetorical. Of course you do get convection loops, but in general, on average, air does *not* go up just because the air above it is colder. In fact, the chimney effect has nothing to do with different temperatures at different heights, only with the fact that the hot air inside the chimney is less dense and therefore would require less pressure difference between bottom and top to support its weight. The pressure difference is imposed by the atmosphere, and will make the hot air rise. The excess pressure difference, and therefore the available power, is roughly proportional to the height of the chimney.
This is not a new idea. I remember it on Popular Science in the 70's.
I've also seen it proposed running the other way. The tower is white to not absorb light, and you inject water at the top. The water evaporates as it falls, cooling the air in the tower. The heavier air, being more massive, creates a down draft. If you use the right sized droplets, you can use sea water, the water at the bottom is concentrated brine, and you have cold moist air flowing out from the tower. THIS can be used to effectively grow crops. One proposal suggested that the extremely heavy dew could water pasture for miles around.
Or you use the desert to heat water. Inject the water into the updraft. This reduces the lapse rate as the column of air rises, so you get more lift out of a given temperature. Hot water can be stored for night use. This requires a fresh water source. If you use sea water you are creating a plume of salt crystals down wind.
Not clear to me which mode makes more power.
Third Career: Tree Farmer Second Career: Computer Geek First Career: Teacher, Outdoor Instructor, Photographer.
I like your analogy, but you need to work on the part where water vapor floats down through liquid water ;)
And you complacency is an insult to all the people that make change happen.
Get involved and stop being a lazy fuck under the excuse 'I can't do anything'. OF curse they aren't outside your control.
Whiny bitch.
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Either were they...before the tower of DOOM was created.
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Context...remember context.
"requires almost no maintenance"
What are we talking about here? that's right, power generation. This does require almost no maintenance when compared to other means of generating power. And they are correct.
Monsoon are large scale sea wind. Created because the sea cools slower then the land.. so I'm not sure if that's the word you wanted.
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True, it should be something that is easily figured out before anything is built so it should at least be explored and may be something that should be considered after it has been built since this is essentially a prototype and may have all sorts of interesting structural and atmospheric challenges.
I'll meet you at the intersection of "Should be" and "Reality"
I'd say you're the one being complacent, by tossing childish names at people you know nothing about in a conversation you weren't a part of.
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