Ask Hackaday: Saving The World With Wacky Waving Inflatable Arm Flailing Tube Men

This is a solution to global warming. This solution will also produce electricity, produce rain in desertified areas, and transform the Sahara into arable land capable of capturing CO2. How is this possible? It’s simple: all we need to do is build a five-kilometer tall, twenty-meter wide chimney. Hot air, warmed by the Earth’s surface, will enter the base of the chimney and flow through turbines, generating electricity. From there, air will rise through the chimney, gradually cooling and transferring energy from the atmosphere at Earth’s surface to five kilometers altitude. This is the idea behind the Super Chimney, It’s an engineering concept comparable to building a dam across the Strait of Gibraltar, a system of gigantic mirrors in Earth’s orbit, or anything built under an Atoms for Peace project. In short, this is fringe engineering.

This is also, ‘saving the world with wacky waving inflatable arm flailing tube men.’

The idea of building tens of thousands of fabric chimneys, placing them all around the globe, and cooling the Earth while sequestering carbon dioxide is fantastic. Ideas are simple, implementation is something else entirely. There are also obvious problems with the physics presented in the Super Chimney presentation, but these problems don’t actually make a Super Chimney impossible. We need more eyes on this, so we’re opening this one up as an Ask Hackaday. What do you think of this audacious scheme, and is it even possible?

Actually Building the Tube Man

A schematic of the Super Chimney. Credit superchimney.org Click to embiggen.

Before we get to the science of the Super Chimney, attention must be paid to the engineering and construction of this bizarre device.

The Super Chimney would be the tallest man-made structure on the planet. It would be made out of fabric — specifically, the same material used for hot air balloons, sourced from AliBaba. At the base of the structure are several openings lined with air turbines to produce electricity. At the top of the chimney, air is redirected downwards by a ‘mushroom cap’ to provide lift.

This is an exceptional engineering project. A single Super Chimney would require 300,000 square meters of fabric, a tremendous amount of land for the proposed guy wires, and the initial erection of the Super Chimney would mean carrying 112 tons to an altitude of 5 kilometers. Lifting the Super Chimney is actually easy when your tongue is planted firmly in your cheek — it only requires building the largest hot air balloon ever made. A dozen of the largest helicopters ever made or a pair of the largest airships currently flying could lift the Super Chimney.

If this is starting to sound dumb, you’re right. However, we’re only dealing with the crazy and impractical right now, and not the impossible. We’re not even dealing with zoning, land use rights, or FAA clearance at this point. What about the science?

Someone Failed a Physics Exam

Compression and expansion of air inside the Super Chimney. Credit superchimney.org

The key scientific concept of the Super Chimney is adiabatic cooling. That’s a link to a Wikipedia page, the text of which contains a bit of the script for the Super Chimney video. The basic idea of the Super Chimney is as follows: hot air, warmed by the Earth’s surface, is drawn into the chimney. The hot air rises through the chimney. The pressure on the hot air rising through the chimney decreases, allowing it to expand. Since the hot air is contained in a chimney, it has nowhere to expand and simply speeds up when traveling through the chimney. When the hot air gets to the top of the chimney, it’s traveling at 500 km/h. If you put some turbines at the base of the chimney, you’ll be able to generate about 100 Megawatts of power.

However, the video for the Super Chimney uses a slightly incorrect analysis for why the chimney works. The word ‘adiabatic’ is used and gets a few points for that. The Wikipedia explanation of ‘parcels of air’ is still used, though. The correct way of analyzing the Super Chimney is continuously, and the air pressure doesn’t change anyway; atmospheric pressure is, as always, a function of the column of air.

How Do You Analyze This?

And so we come to the Ask Hackaday segment of this post. How, exactly, do you analyze this very interesting physics problem? If I had to throw out a few ideas for this problem, we’re dealing with an increase in air speed throughout the Super Chimney, so Bernoulli’s principle will come into effect. Additionally, what happens when the Super Chimney is sitting in a temperature inversion, or when the atmosphere at the surface is cooler than the atmosphere at altitude?

This is one of the weirder engineering debunkings we’ve ever seen. We know the Batterizer is a terrible idea simply by looking at datasheets. A Solar Roadway is dumb because tires like traction. A five kilometer tall wacky waving inflatable arm flailing tube man is so far outside the usual set of problems that it seems no one has any idea where to start. So what say you, Hackaday? What do you make of this idea? Is there a seed of an idea that could do something amazing — with the realities of execution just needing to be solved? Are there assumptions with fundamental flaws that make this impossible?

118 thoughts on “Ask Hackaday: Saving The World With Wacky Waving Inflatable Arm Flailing Tube Men

    1. In fact, the author mentions this in the “principle” section …
      “In a conventional chimney, like one in a house, the difference in temperatures is maintained by burning some fuel.”
      … but never actually goes on to explain how the Super Chimney will work with this difference in temperatures. You have to START with an imbalance and then MAINTAIN it. When the fire in my fireplace burns out, the air doesn’t keep flowing! Making the chimney taller won’t make any difference.

      If you fill a hot air balloon with air, no matter how tall, it doesn’t just magically start to rise. You have to heat the air inside. You can make a Solar Balloon with a dark material to capture heat, and probably some elaborate scheme to have it rise then fall and spin a turbine in the process, but why not just put a solar panel on the ground instead?

      1. tl;dr Engineering issues aside: the core problem is that the author expects that air will flow through this chimney and spin the turbines, but there is no plausible reason why the ground-level air would “prefer” to go up the chimney instead of just… floating up there in the atmosphere.

        Your dozen helicopters will lift the cap to space, release it, and it will fall majestically to the ground.

        1. Wikipedia has an article on the “Solar Updraft Tower”, which covers the same idea, but makes far more sense.

          https://en.wikipedia.org/wiki/Solar_updraft_tower

          Essentially, the tower is only the half of it (and you build it out of something sensible, like insulated concrete or whatever). There is a wide “solar collector” area, essentially a massive greenhouse, surrounding the chimney. This captures sunlight and heats the air to a much higher temperature than the surrounding atmosphere at ground level, causing the air to “want” to escape up the chimney, and spin a turbine in the process.

          Of course, one wonders why a solar panel might not achieve the same effect, but there are maybe engineering or reliability concerns that this addresses.

          1. Way more sensible implementation there; shoveling more solar heat into the device and making the tower free-standing solves most of the problems with the Super Chimney. At that point, it just becomes a question of economics, how much cost (and energy) is needed to construct it vs how much you’ll get out of it.

          2. The point of the tower is that the ground retains the heat far longer and works through the night and even through couple cloudy days, producing near constant power whereas solar panels peak in output for a few hours around midday, experience wild fluctuations in power due to clouds, and then die off completely right through late afternoon when the power demand is climbing quickly towards the evening peak which creates major issues for grid operators. The updraft tower instead has peak capacity towards the evening due to the thermal lag of the ground underneath.

            Solar panels in general are a massive headache because of their low capacity factor. See California and the duck curve:

            The issue is that large powerplants can’t respond to the load variation. They have a limited ramp rate due to their size, so smaller less efficient turbines and even diesel engines have to be brought online. Wartsila is currently making a killing selling marine diesel engines for grid balancing operation in the west coast.

          3. If you’re going to add solar panels under the greenhouse, have each one resting on a thin container full of water. Join up the containers with a series of tubes underground.
            The water absorbs energy from the solar cells, which warms the ground, and extends the thermal difference effect when the sun goes down.

            Oh, and unlike the Wacky Wavy chimney at 5km, solar thermal towers can get by with a chimney at 1km (although higher is better).

          4. “There is a wide “solar collector” area, essentially a massive greenhouse, surrounding the chimney.”

            So.. I guess it would be black or some dark color in order to maximize the amount of solar energy collected. Did we forget the original problem that this thing was supposed to be solving? Energy that would have reflected back into space should certainly be allowed to do so!

        2. I think the premise is that the column of air will move rapidly up due to temp differences. So rapidly that the nozzles on the top will keel the mushroom at altitude and keep the whole mess off the ground.

          The converse is that the bottom will be under suction. It’s the low pressure at the bottom of the tube that draws the surface air in and drives the turbines and feeds the nozzles at the top.

          Major flaw: that means it can’t be made of flexible, collapsible light-weight fabric, as the lower portion of the tube will look like a ribbon rather than a cylinder. And once you cut off the flow at the bottom, the whole tube will collapse, the nozzles won’t have anything to blow, and down it comes like a giant bulb-headed flatworm…

        3. I presume this works like a traditional solar chimney. There is energy put into the system by solar radiation that heats the air above ambient and keeps it hotter through the whole 5 kilometers. I stumbled upon Solar chimneys driving wind turbines in the 80’s and it was suggested to put up a pilot plant in Spain, that was before they built their solar thermal plants.

    2. The first answer nails it: The problem is the Super Chimney is dependent on the temperature and pressure inside the chimney being different from the air outside it. For hot air to rise, it needs to be hotter relative to the air surrounding it so that the less dense; otherwise you have simply put a dividing wall with equal air conditions on both sides and there will be no movement. If the goal is to use solar heating to create a temperature difference, I’d have to run the math to see how much heating can be done, but there’s an obvious problem – once the sun sets, your solar chimney falls down, and you have to put it back up every morning!

      1. Matt, because I really want to see a 5km tall wavy arm dude the solution is simple, build a huge solar collection plant next door and store all the energy in molten salts then at night you can release the energy into the base of the tower as heat to keep it upright. Lets make this happen cause I really need to see this now that Brian’s put the thought in my head. lol

      2. “For hot air to rise, it needs to be hotter relative to the air surrounding it so that the less dense;”

        Or you can think of it as exerting more downward force since it’s higher pressure. The two ideas are obviously equivalent (it’s just the derivation of Archimedes’s principle), but I like to think it’s easier for people to understand that hot air is higher pressure, so it pushes down on the ground more and goes up.

        “once the sun sets, your solar chimney falls down, and you have to put it back up every morning!”

        You could easily store some of the energy to maintain the tower during the evening, e.g. via melting salt.

        The more fundamental problem is that the only advantage that a (proper) solar updraft tower has over other solar thermal projects is that you can make the collecting area stupidly large – but as a tradeoff, the conversion efficiency is stupidly low. A prototype in Spain had an output of 50 kW using 45,000 square meters. The solar irradiance on that much area is 61.65 MW. That’s… very bad efficiency. For comparison, Solar Two was 82750 square meters, and output 10 MW, which is a solar efficiency over 100 times higher.

    3. I use a full length piece of black PVC 4″ pip added to the vent of a port-a-potty. The black pipe heats up, air rises, the little blue room is well ventilated plus the air flows down into the tank them up the pipe. Same principle.

      1. In the days of tube electronics chimneys were incorporated into the design for cooling. Even a ft long chimney fed from the top of a high power tube gave plenty of convection to cool the whole box.

  1. While the air maybe moving at 500km/h, it’s still going to contain moisture, and as it cools that moisture is going to have to go somewhere. I’m imagining it’ll condense on the tube, and being fabric be absorbed, only to freeze solid due to the lower temperatures and so make the tube heavier… Then the built up of ice will either cause the entire thing to collapse, or the air to slow down causing even more ice to form?

    Of course, I maybe entirely wrong too, please let me know!

  2. So a wind turbine with a vertical axis built at sufficient altitude, spinning due to convection effects wouldn’t do this without a constraining fabric tube?

    Convective airflow can pull air horizontally close to the ground, which will make constructing the thing a lot easier, and could harvest horizontal gradient winds due to high and low pressure differential, plus a bit of Coriolis. Pity nobody’s putting those up as they could be really handy. Oh, wait….

  3. Crazy halfway-to-space ideas go back a long way. Back in 1978 O’Neill’s L5 plans spawned a song that included the consequences of beaming power to Earth from on high:

    https://groups.google.com/forum/#!topic/rec.arts.sf.written/Hg8iK_9zuaU

    The particular lines of interest are,
    “You don’t need no oil, nor a tokamak coil
    Solar stations provide Earth with juice
    Power beams are sublime, so nobody will mind
    If we cook an occasional goose.”

    Similarly, there is the wacky space elevator: https://en.wikipedia.org/wiki/Space_elevator

    But then Goddard was a wacky nut back in 1926, and his rocket science actually worked.

  4. $THEY want the poles to melt because $THEY want to get access to the resources located there.
    As long as there is coal and oil to dig out, $THEY will do it.

    There will be no substantial fight against global warming as long as you can profit from polluting the world.

    Happy ends are for the movies… not for real life!

    1. Since cooling has already started, anything you do will be deemed a success. There will be many fights over whose efforts caused warming to cease. Please people. Ignore that bright thing in the sky with its many cycles and modes.

          1. From my fellow physicists, atmospheric scientists, instrumentation and space experts, geologists, USGS Ice Dynamics people I know personally, and climatologists. I don’t know a single one who doesn’t think that “climate” has become big business and job security. And they agree that AGW as a crisis is ridiculous. In fact I have never met one who would have signed that UN letter or whatever it was. The religious like fervor of people who are not experts (as evidenced often in HaD comments for example or any time the topic comes up where comments are allowed) should be enough to tell you there is a problem. Maybe the attacks on those who who are against panicking should be a clue. Government officials declaring that coastal Florida will soon be flooded or that sea turtle eggs are being destroyed by rising seas have no clue how much sea level has changed per decade, or that it has declined in the last two years. Nor do you hear that we are entering a great solar minimum that can last decades or 150 years, or – nobody knows, like the mini ice-age that produced the tight-grained trees used by Stradivarius. Just sayin. Not a blind believer and not afraid of change.

          2. @TheRegnirps – From you and your friends. Ok. Who are you and who are they? There are plenty of self-described scientists and people with papers from diploma mills that try to use that as an argument from authority for stupid shit. Just look a the young earth crowd.

            As for the ‘solar minimum’ So what? We are entering a period with fewer sunspots. There will be fewer magnetic anomalies on the sun for a while. That sucks for hams that want to bounce radio signals off the ionosphere but what does it have to do with the temperature of our planet? Not a damn thing.

          3. >”but what does it have to do with the temperature of our planet? Not a damn thing.”

            Sunspots and the flares reduce the effective brightness of the sun by 0.1%, and the particle showers influence cloud nucleation. It sounds small, but the total anthropogenic climate forcing is estimated to be 0.6 – 2.6 W/m^2 which compares to about 1000 W/m^2 direct sunlight on average and around 250 W/m^2 after clouds and night are taken into account.

            So even 0.1% change in the sun’s brightness may make a 0.25 W/m^2 difference in climate forcing, which is pretty significant: it’s anything between 10% to 40% of what we estimate is caused by people.

          4. “Sunspots and the flares reduce the effective brightness of the sun by 0.1%,”

            More sunspots indicate a *brighter* sun, not a cooler one. The sunspots themselves are locally cool, but they occur because the sun is in general more active. No sunspots means a dimmer Sun, as evidenced by the Maunder Minimum’s correlation with the Little Ice Age.

            But the overall climate correlation to solar activity is under 1 degree C or so. The term “Little Ice Age,” caused by the Maunder minimum (a period of extremely low solar activity) makes it sound as if the Earth got significantly cooler, but it was really only ~half a degree C or so cooler. It wasn’t an Ice Age at all.

            We’ve already exceeded that in the other direction – that is, if the historical average temperature anomaly is -0.4 C, the Little Ice Age was -0.8 C, the Medieval Warm Period was 0 C, and we’re currently at +0.95 C. Solar activity decreasing in the future might gain us back a half-degree or so, but that’s well within climate estimate errors.

      1. “Since cooling has already started”

        You could almost certainly cherrypick data enough to claim that warming has *slowed*, although any rigorous analysis would still show you’re wrong. But at least you wouldn’t be outright wrong even at first glance.

        But 2016 was the warmest year on record. So… it’s kinda impossible for cooling to have already started.

        1. I assume you are relying on someone elses results, and that you believe they are not cherry-picked, and that the analysis is valid. You might be surprised by how many of those experts do not know that the solution to every first order differential equation is exponential.

          1. Nope! I’ve actually seen the data, and the full analyses, and even gone through parts of it myself! It was fun. It’s a good project for an undergraduate, too.

            The data’s all public. It’s here. Good luck finding anything that indicates a cooling trend. Like I said, you could *maybe* argue for a *slowing* of warming, primarily if you find a way to throw out the past few years of data. If you would say that, I’d just think you’re an ordinary skeptic. But finding a *cooling* trend in that data is kooky-level.

          2. Just think about the pending catastrophe and refugees from sea level rise. According to
            NASA, sea level is rising somewhere between 0 and 3mm a year. Take the 3mm for example. Consider something fairly devastating like the storm surge in Texas right now, predicted to be 1 to 2 meters, and compare is to the devastation of sea level rise.

            At 3mm per year, for sea level to be equal to the storm surge will take 330 to 660 years. Not fast enough to worry about for people alive today, or their children or grandchildren. At some point though, offspring will decide not to live where their parent live and choose to go somewhere else. Like most everyone does now.

            First, I can’t see how this is a refugee crisis, or even migration. Why then are officials from the Governor of Florida to the Seychelles calling this a crisis?

            Second, I can not believe that a change in behavior by North Americans and Europeans can make a measurable difference. Or that (if needed) much better smarter mitigation can not be performed 200 years from now.

          3. “Lmao, here you go…..raw data not “adjusted” by the NOAA”

            Take all of that data and try to find a global “cooling” trend that’s started. Good luck.

            If you want to say “there’s no evidence that the planet’s warmer than it’s ever been,” sure. If you want to say “there’s no evidence of an unprecedented rise in temperatures,” sure. All those things just make you a normal skeptic, and that’s fine. Still wrong regarding the overall risk, but it’s a reasonable argument and takes much more effort and analysis to show that. But saying that the planet’s currently “cooling” requires completely ignoring data.

        2. You’re comparing *sea level rise* to a storm surge? Seriously? Storm surges result in entire towns being under water briefly, and houses having water up to *window* level. But then the water *drains*. With sea level rise, they *don’t*. Towns become uninhabitable way earlier.

          “First, I can’t see how this is a refugee crisis, or even migration. Why then are officials from the Governor of Florida to the Seychelles calling this a crisis?”

          Because cities off the Florida coast are becoming un-insurable. That’s the first step: banks refuse to offer insurance, then banks refuse to offer mortgages, then houses become impossible to sell, then people are forced to move.

          1. With storm surge I’m comparing sea level rise to heights we actually see, in order to see what it means. It isn’t complicated.

            As for house insurance, why do you think the companies will not insure against a potential problem 300 years in the future? The house will be replaced several times by then! Have they succumbed to Al Gore hysteria?

            The government in the Seychelles wants money from the US and the UN to mitigate sea level rise. I have personally offered to exchange land on Puget Sound that has a high enough bank to be safe to over 1000 years, for equivalent water-front in a vacation resort in the Seychelles. No takers.

          2. “With storm surge I’m comparing sea level rise to heights we actually see, in order to see what it means. It isn’t complicated.”

            The fact that you think you a storm surge, which last days or less, can inform you as to the effects of permanent sea level rise really just eliminates any point of common ground here.

            “As for house insurance, why do you think the companies will not insure against a potential problem 300 years in the future?”

            Because they’re already abandoning those areas. Risk management.

          3. It doesn’t matter how long a storm surge lasts, it physically shows the levels that are being talked about. I thought that was obvious.

            If people are abandoning waterfront on the basis of a possible problem 300 to 600 years from now, again, I’ll trade for it.

            It is easier to judge people’s intent from their actions than their words. How many of the consensus scientists have made investments based on this? Why not buy land, say 50 feet above mean high tide, in Boston, and build a boat ramp? If you build it, they will come – eventually it will be a very valuable piece. Or any of a great number of opportunities that will only bear fruit if the sea rises sufficiently? Do you see any of that happening?

          4. I don’t know why you can’t understand that damage from something being wet for 2 days is different than damage from something being wet constantly.

            “It is easier to judge people’s intent from their actions than their words. ”

            Exactly! Which is why I look at people whose job it is to evaluate risk – namely, insurance companies. And they’re pulling out entirely from coastal regions, because the risk is too high.

          5. Also, you don’t buy high-water land on speculation because when the sea levels rise, the land doesn’t magically become high-value seafront property. The slope of the land’s still shallow. It would take centuries to carve out a new seashore. When sea levels rise, you don’t get *new* beaches, you get *no* beaches.

          6. I will assume you are playing dumb to make a point. What does water damage have to do with seeing how high the water will be? Can you see the depth in a bathtub if your skin has not wrinkled?

          7. To quote you:

            “Consider something fairly devastating like the storm surge in Texas right now, predicted to be 1 to 2 meters, and compare is to the devastation of sea level rise.”

            That’s where water damage came from. You can’t compare a storm surge to rising seas. Instead, you do something crazy – like, I dunno, actually have a study, do risk assessment, and evaluate things critically. Which is what tons of communities, corporations, and government organizations have already done. Like this one.

            And, like I’ve pointed out, the conclusions that some of the most forward-thinking organizations have come to (insurance companies and the military) is that climate change and sea level rise is going to make things very, very bad for certain areas.

    2. $YOU are living in a nightmare of your own making. CO2 is not a pollutant. And climate change has always happened-we call them “seasons.” To expect the temperature to be constant over the earth is idiotic.

  5. Descriptions I’ve seen of this previously included a large greenhouse structure at the bottom which heated the air to cause it to rise. I think it was supposed to be used for farming too, possibly you could harvest the water coming back down the chimney when the air cooled.

  6. It seems it would be cheaper to just build hollow skyscrapers at much lower elevations in the city where the impact would directly be felt, and the power would be of some use. The only constraint would be height and noise. I don’t know the effects of a 100m-600m cooling chimney. It won’t be as effective as the super chimney, but it would be much cheaper.

    1. This. Only instead of hollow, make them packing facilities. you still need a pressure differential, so solar heating of large tinted concrete bases filled with tubes leading in to the central column. mirrors to concentrate sunlight onto them. turbines placed in the central column nearish the top. quit worrying about the cooling aspect.

    1. I am not trying to start a debate here just stating a “shower thought”. It is actions like this that cause me to still question some of the AGW claims and and calls to action. Instead of using the lake Nyos area for research into natural sequestration and ways that we could adapt it to our use or teaching the locals to safely remove the carbon dioxide and sell it for some of its many uses,the best scientific answer seems be to just dump it into the atmosphere. Things like this cause a small cognitive dissonance when I read reports from the IPCC.

        1. I’m sorry Megol, which ideas did you think were stupid? The research into sequestration, of which there are a number of projects attempting already or the extraction for use idea which Ren then informed me is being done at another site nearby? And really that’s as far as I can go since I cant seem to follow the rest of the sentence.

      1. Building a sequestration system was probably not in their budget.
        You might argue that they could have made the money back by selling it but..
        – The location contained “mostly rural villagers, as well as 3,500 livestock” and that was before 1,746 of them were killed. Does the infrastructure exist to transport the CO2 to more lucrative markets?
        – Who installed these pipes? The Wikipedia article doesn’t say. I’m guessing some sort of government entity. Are they normally in the business of selling things? Do they want to be?

        If capturing and selling this CO2 was viable I suspect some company would have approached the locals looking for permission to do so by now.

        “Things like this cause a small cognitive dissonance when I read reports from the IPCC.”
        Was it the IPCC that installed these pipes? Or was it a team of engineers from the 1980s (when AGW was not yet as recognized as an important problem as it is now) who were tasked with preventing another local CO2 induced die off, not saving the world.

        But hey.. you know.. those scientists.. they are all really just in it together, part of the same conspiracy to put the Free Mason Illuminati atlantian space reptiles from inside the hollow earth in charge of all our bedrooms. Surely those pipe guys and the AGW guys are working together.

        1. I really had not planned to respond to this thread any more and if you had not included that last paragraph accusing me of being a conspiracy nut job I would have just let it die as the rest of your post was valid. After this post I will not respond anymore, please let this die.

          “Things like this cause a small cognitive dissonance when I read reports from the IPCC.”
          I no longer give media articles much trust so I do try to find the sources and read those reports before giving weight the subject presented And I will encourage you to also go and read through these reports. https://www.ipcc.ch/report/ar5/
          Once you have read how these reports work and what they actually present then look again at how the media presents them and how actions are taken in comparison, then I believe you will understand the cognitive dissonance I feel.

          1. Huh. Funny that the part i didn’t really expect to be taken seriously is the part that caused a response. I will check out the reports. Don’t worry, that will effectively kill this thread for you as this article will be archived and buried by the time I finish.

            I do wonder though.. what can I possibly expect to read here, in a report put together by an international panel on climate change that would conflict with the handling of a specific event in a specific place by specific people at a point 30 years in the past that would cause any cognitive dissonance? Well.. here’s to finding out the long way I guess..

  7. I think there is an actual engineering solution to this, at least for smaller, more rigid towers. You build a large greenhouse structure at the bottom and use solar energy to creat your temperature differential (called a solar chimney). You have a large footprint for your greenhouse structure, and any thermal storage built into it if you want to try to operate 24/7, and you put your turbines at the bottom of the chimney cylinder. Moisture is going to condense on the way up, but well before freezing temperatures for the most part, and draining it probably would be a tractable problem. This would work to *some* height, but I doubt anywhere close to 5km.

      1. When that caldera blows sometime in its 600,000 year cycle (which we are coming up on) it’s going to ruin a lot of pictures, scenery, wild animals as well as starve a lot of the earth’s population.
        Maybe they could disguise the drilling sites with some of those fake microwave tower branches. ;-)

        1. Sure but after all those humans die off there will be a lot more scenery and wild animals to take pictures of. Nature recovers fast. Just look at Chernobyl or the Bikini Island reefs!

        2. Direct and indisputable geological evidence of past eruptions show the results of this caldera erupting to repeatedly result in total devastation across large percentages of the continent and serious negative effects observable on a planet-wide scale.

          … so naturally we want to drill into it to “just release a small amount of the pressure and heat.”; Essentially the human version of the lemmings “rolling the dice” rush to suicide.” It all make perfect sense seeing as we’ve so much experience now with drilling, fracking, and gambling, … combined with our certain knowledge that we can successfully count the cards and beat the system “Every Single Last Time.”.

          1. A super volcano is so bad it is not something you can hide from and wait out pretty much the only chance civilization has to survive one is if there are colonies on other planets.

      2. Actually I was thinking that if you changed the thermal dynamics (?) of the area enough with the plant then Old faithful may just become a warm mud pit and the national park services would be pretty ticked off about it.

    1. The fact that extracting the heat would create some carbon neutral energy that can be used for base level power generation that can be sold at less then 10 cents per KWh makes it a worth while endeavor.

  8. if we are going to do massive projects with gigantic amounts of fabric, wouldn’t it make more sense to make a large, lightweight space structure of opaque fabric, to block the UV/IR/Visible light from getting here in the first place?

    wouldn’t take too big a structure to tip the balance, no need to block the sun entirely.

    probably need to build in some form of liquid/gas cooling so you don’t burn the whole thing to ash, and then redistribute the heat back out into space away from the earth using the same fabric panels as radiators (probably need a large “thermal battery” composed of a very energy dense fluid like water, to store the heat in the time it takes to orbit to the dark side of the earth)

      1. Martin, I think you would also want some solar collectors and some Ion drives to counter the silver effects, on the plus side with enough of them we could schedule solar eclipses in thee future.

  9. It would work at night but less, it’s very cold above. However the tower would have to be rigid for sure. It reminds me of a cover article on one of the pop sci style zines in the year 1957. Why we need stratospheric airports. 7 and a half miles high with a base city-shelter as high as Denver is to sea level. Nearly 40,000 feet, cruising altitude for jets. A rocket powers the lift to the top where fighters can engage incoming Soviet bombers.
    There is a lot of Pie up there!

  10. “The hot air rises through the chimney. The pressure on the hot air rising through the chimney decreases, allowing it to expand. Since the hot air is contained in a chimney, it has nowhere to expand and simply speeds up when traveling through the chimney.”
    Would there not be an outward or inward force on the walls of the chimney due to the pressure/temperature differential between the inside and outside of the chimney? With some of the big numbers thrown around above, I’d guess one could do a back of the envelope calculation to see if these forces would be within reason. Let alone there would be tension on the fabric due to holding up the weight of the fabric below. I love the idea of a space elevator, but tension becomes a key issue there iirc. Just my first thoughts on the matter.

  11. Traction is the least of the problems with solar roads. The bigger issue is that if the solar panels are in series, a single car on the road will cause the entire road to produce zero power due to shading. But you can’t put them in parallel either because then you will produce power at massive current and low voltage, which will require incredibly expensive and thick wiring. So now you need separate inverters for every few panels which again is incredibly expensive, and you need to synchronize those inverters to the grid and each other.

    1. No that’s not even a problem assuming the people involved had any kind of knowledge. It’s basic and easy to handle.

      That the solar panels don’t produce much energy is a real problem.

  12. HaD asks: “How, exactly, do you analyze this very interesting physics problem?”

    My first thought is that anything like this is functionally a heat engine. Without a source of heat. Everything else is just wasted effort.

    A true solar draft tower has a huge collector at the base that traps/collects low delta T energy and uses a process to extract as much of the energy out of a volume of mass. You can augment this with photovoltaics, mirrors etc but in the end you’re dealing with at most the amount of energy the sun puts down over a given square foot/meter of space and trying to efficiently trap/convert this into electricity or other more useful energy (steam, wind by way of updraft, knocking about loose electrons in semiconductors, etc). You can extend this process by storing a surplus for work at night so that you get an even output but thats a different issue.

    The proposal’s website even says this in the FAQ section: “How is this different from a Solar Chimney? A Solar chimney was designed to produce electricity, and that is the only benefit it delivers. Solar chimney uses giant green houses to concentrate heat, so the chimney can be shortened. Those green houses will trap more heat in our atmosphere and therefore will contribute to Global Warming. Unlike the Solar Chimney, the Super Chimney is designed to cool atmosphere. It does not need green house and is capable of reducing Global Temperature by increasing thermal exchange in the atmosphere.”

    If you read that right, they are claiming greenhouses are making our planet warmer, better stop growing food! They claim that a Solar chimney contributes to Global Warming! umm sure if you live in ignorance about how they work.

    Further they claim in that statement that you can use a “shortened” chimney for power production, doesn’t a chimney’s efficiency increase with height, so If I wanted more power from my power producing Solar Chimney I want it as high as I can build?

    This proposal has no collector by design, no delta T and thus no useful energy that can be extracted for work, including keeping the entire thing up in the air. No matter how much you try, you can’t beat Thermodynamics. So there you have it they want to make a giant solar chimney in the desert without a collector because the planet would get too hot if you actually collected the energy and extracted it to try to do useful work. (Say converted heat to electricity rather than leave it as heat)

    As for a hot air balloon it will only stay up as long as its source of heat/fire/fuel is available, after that it’s going to come down, the heat will transfer from one side of the fabric envelope to the other and the weight of the fabric will cause it to be attracted by gravity back to the largest collection of mass. With a solar powered inflatable tube thats every night if it ever got off the ground to begin with, but it can’t since there is to way to concentrate the heat to start the process!

    Start with a mistaken concept/understanding and build on it and you get this proposal.

    1. “Further they claim in that statement that you can use a “shortened” chimney for power production, doesn’t a chimney’s efficiency increase with height, so If I wanted more power from my power producing Solar Chimney I want it as high as I can build?”

      There must be an optimal diameter and height. In a real atmosphere the pressure goes down with altitude as well as the gravitational force. Analysis based on density changes due to temperature will not work and it is much more complicated. I would guess that being anywhere near the height at which the internal and external temperatures have equalized (due to thermal conduction and expansion with altitude) is useless.

      On the other hand, thunderheads reach to 90,000 feet and with very impressive vertical winds. Somewhere in between a few hundred feet and 90,000 feet is a sweet spot for any given diameter and even then it might be worthless. I can’t see how this idea is much different from a big region paved with blacktop that is surrounded by fields. Watch the vultures and buzzards.

  13. Ok, everyone’s clearly debunked the whole thing from an energy point of view.
    Let’s say it magically worked; wouldn’t there be issues with that airflow building up static charges? Might you have clouds and thundershowers inside it?

    1. Or you could redirect the static charge to do usefull work – https://hackaday.com/2014/08/09/funky-looking-motor-is-powered-by-static-electricity/

      or if you have a water issue,

      Even more down this thought process is that if you have a grounded structure so high up you would potently find you have no thunderstorms because the charge can dissipate to ground before they can build up to bridge the airgap vs taking the tower path.

      From – https://en.wikipedia.org/wiki/Atmospheric_electricity and http://home.gwi.net/~erichard/atmelect.htm

      Atmospheric electricity is always present, — and is about 100V/m. There is a weak conduction current of atmospheric ions moving in the atmospheric electric field, about 2 picoAmperes per square metre.

      https://www.youtube.com/watch?v=ENeDkGce5-4 – This video shows what kind of power you get at just 130 feet.
      https://www.youtube.com/watch?v=2rVdEhyMR6A – Atmospheric Electricity

    1. A hint: we are already messing with the entire planet and have done so since at least the industrial revolution. With measured facts:

      Heating due to release of greenhouse gases.
      Ozone holes (actually significant reductions in ozone layer thickness).
      Extinction of many species.
      Poisoning with pesticides, crap (that is human and human related shit, excrement), radioactive elements, heavy metals, industrial chemicals etc.
      In some cases making habitable land into deserts.

      1. Yes, and no.
        Yes those things have started to affect the whole planet, but no there is no direct intent to do so, it’s a byproduct of carelessness.
        And there are many complaints and agreements made between various countries as a result of the ‘classical’ pollution. And many countries created environmental agencies to regulate and deal with that stuff.

        But the subject is deliberately experimenting in changing the entire planet, and I would like to point out that in total disregard of what up to 390 million halfwits think, the US and UK do NOT own this planet.
        And as I said before, how would you feel if China or Iran or Saudi Arabia some such decided to change the ecology of the entire planet on purpose to their personal liking with wild experiments?

  14. I have a vague recollection that a similar idea was used in a sci-fi story from the mid-late ’50s or early ’60s (Heinlein, Asimov, Clark??). The chimneys were constructed of something like giant plastic bubble wrap and each bubble helium filled so that the whole thing was self-buoying; guying required to keep it from floating away. Same idea with wind turbine generator in the bottom and water condensate collected. The author also included a search light in the bottom pointed straight up the shaft for aircraft warning.

  15. Interesting. A couple decades ago this was a rigid tower but the thought was to spray water in at the top of it. Evaporative cooling was supposed to make it downdraft with the same turbines at the bottom to generate the power.

  16. There is so, so much wrong with this that it’s hard to know where to start. Let’s be clear – the idea at the site itself is total nonsense.

    But… I’ll try! Here’s the basic problem. Lots of people are claiming that the Super Chimney idea is just missing a source of heat at the bottom, and that he must’ve just not mentioned it. But really, if you read the site, that’s not what he’s talking about. He’s just pretending that because the air at the bottom is *warmer*, and the air at the top is *colder*, it has to rise, right?

    This is directly in the FAQ at the site:

    “2.I don’t understand what is the difference between the air inside the chimney and the air outside the chimney. They have the same temperature so why will the air inside the chimney be rising?
    At the bottom of the chimney air has the same temperature inside and outside. The inside and outside air will be rising up. ”

    This is wrong. Warm air doesn’t rise just because it’s warmer. It rises because it exerts more pressure *downward* than the other air around it. Air at ground level isn’t constantly rising! Air at the ground is in hydrostatic equilibrium – with the pressure from the gas balancing the force of gravity. Hot air only rises if it’s hotter (has more pressure) than hydrostatic equilibrium allows.

    I mean, this is fairly obvious. If there was a constant upward wind, we’d kinda know.

    So what’s the basic problem with the idea? (Not “lack of heat,” because like I said, the idea is no added heat, just use the fact that the temperature is different). When you go ahead and build the tower first, and hold it up, there’s *already a pressure gradient* inside the tower that was in hydrostatic equilibrium. What prevents the hot air at the bottom from rising up? The same thing that keeps you from rising up: gravity. It’s the weight of the gas. In order to get the air at the bottom moving upward, you need to give it energy to overcome that balance, and there’s no energy added here, so no updraft.

    Note: a solar updraft tower, which has added heat, is totally okay.

  17. I can see this working. To keep it erect the top edge should be turned inward and back down to steal some updraft energy as lift like a parachute. The weight of turbine-generators at the base will provide adequate anchors and be easily maintainable at that location. The turbines will also be used in reverse to start the energy producing cycle by inflating the tube and initiating the upward flow which would be self-sustaining thereafter.

    I do see one drawback. The hot moist air from ground level injected into higher levels of the atmosphere may create a perpetual thunderstorm downwind. If scaled up too far it could potentially produce a tornado.

    The awesome amounts of user provided hot moist air are proving ample for well over unity energy production and operation in this application.

    There may be benefit of combining this concept with cables and elevator from Earth to Geostationary Orbit.

    1. Come to think of it… that top edge HAS to be turned inwards as described, granting a small structural stiffening of the upper orifice… else each unit will permanently provide a “raspberry” sound effect we’ll hear all over the planet.

  18. So the real question is, can we some how shove Nikola Tesla’s idea of connecting the ionosphere to ground with this? And stirling engines, find a place to shove those in too, for good measure!

    1. The link goes into a lot of details, but the better explanation is shorter – atmospheres, excluding weather concerns, are stable. Air doesn’t just rise or fall for no reason, even if you put a cylinder around it.

  19. Just plant more trees!! Why do people overcomplicate things? Trees suck in CO2 and and produce O2, not of these stupid complex contraptions will improve the air quality and give us oxygen to boot.

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