23 thoughts on “Massive Energy Skyscraper Proposed On U.S.-Mexico Border”

  1. “Water is sprayed into the opening, making the uppermost air humid and heavy. That heavy air sinks and accelerates, reaching speeds of 50 miles an hour before escaping at the base”

    Any golfer can tell you that humid air is less dense than dry air.

    Not saying the system won’t work, just saying their explanation is wrong. Assuming it works, I’d say it is because the sprayed water evaporates, cooling the air. Any car guy can tell you cool air is more dense than warm air.

    This application will require massive amounts of water (and electricity to pump it up to 2,250 feet!).
    San Lois is near the Colorado River, though it’s flow is quite diminished. I’m not sure it can stand having that much water removed from it. Nor can it be expected to always have adequate flow. Lake Mead is way down. Perhaps they can condense some water back out of the effluent air.

    An intiguing engineering exercise!

  2. It’s a perpetual motion machine, and a stupid one at that. Water pumped to the top of the tower cools the air and sinks. Given the weather, the sides will be hot, so the air will warm towards the botton, completely eliminating the gains.

    There’s a reason the stock is trading for a penny.

  3. Wikipedia addresses the issue you raised. The increase in density is caused by the cooling that accompanies the evaporation of water. The site has proposed importing desal water from a source in Mexico, rather than use river or sea water.

    Apparently, they developers expect the pumping to use about 20% of the power output from the plant. They also make the point that this is essential a solar power source, albeit one that functions for some time after dark each day because the air remains warm aloft.

  4. I have not done the math, but it seems to me that the warming of the down flowing air by the heat from the sides of the structure will not be significant. I am guessing but I think that the surface to volume ratio of the tower is too low for the transfer of solar heat through the walls to contribute significantly to the temperature of the air inside of the tower.

  5. Two serious problems with this idea: power (needed to pump water to the 2,250 foot level at the top of the tower at more than 1100 psi pressure), and water (where the f. are they going to get it in southern Arizona’s Sonora desert?). Three problems: high pressure water systems + heat + air = corrosion. T’wont last long, I’ll wager.

  6. I’d like to see the feasibility tested before anyone goes half a mile vertically. That said — if it works, this could be a very good source of energy without burning. All of the issues cited above need to be considered before anyone bets a farm on this, though. And NO SUBSIDIES.

  7. Couldn’t you put water tanks at intermediate levels to reduce the height of the water column? Of course, then you have to deal with large water tanks and pumps way up in the air.

    As I misspellled, an intriguing engineering exercise.

  8. I keep thinking about the effect of the heavier air on the air at the bottom of the column. It will be compressed, hence heated. Seems to me it would hence resist the pressure from above. Maybe it doesn’t matter.

  9. Gamecock,
    It will take half as much energy to pump the water up half way as it will take to pump the water all the way up.

    It seems that the diameter at the base will be about 500 feet, room enough for 52 tunnels of about 30 feet diameter each. The ratio of the area of a 400 ft diameter circle to 52 tunnels at 30 feet diameter each is about 3.5. If the air at the top is moving at 50 mph, the exhaust from the tunnels must be moving about 175 mph, which is about 15,000 ft per minute. The pressure needed to make air flow out through the tunnels at that speed is a few inches of water, not sufficient pressure to cause significant heating.

  10. Thanks.

    Tadchem said it would take 1100 psi to pump water to the top, then suggested the high pressure could cause problems. I was thinking a way to avoid the high pressure was to pump it up in stages.

  11. Another question: what will the effects of wind be?

    I was thinking an inverted cone cap at the top might achieve some supercharging effect by directing some wind down into the tube.

    Could wind at the base affect output? If air is exiting at different speeds from different sides of the base, could that create problem air flows inside?

  12. Will it work on a cold day? Suppose it gets down to 40 degree. How much does temperature drop at night in that part of the world? Will it run at night?

  13. I’m no expert, but evaporative cooling requires hot dry air, so if it runs at night it will be far less efficient then. I don’t know if it would be worth it to run it then.

    Any wind is going to be at much lower speed than the air coming out of this thing, so I don’t think that will be a noticeable effect.

    The Forbes article seems to indicate that the entire city of San Luis, AZ consists of a single Walmart. 😀
    As such, I doubt there will be many noise complaints.

  14. I do not know the answers to your questions. I suppose those items were what the company was thinking about when they selected an area near several Air Force bases so they could get access to high quality meteorological data. The article says the location is 5 or 6 miles from a small town, which suggests that noise will not be an issue.

  15. I lived in Tucson, or what Yuma folks consider the Arctic. Summer nights sometimes stay above 90 and often above 80. A swamp cooler is highly effective in Tucson, more so in Yuma, so that part of the idea makes some sense.
    Surely there’s been some kind of smaller-scale study.

  16. Not necessarily. Water is a dense source of coolness and is used to expand and cool significantly more air. Air cools 1 degree per gram with about 0.25 calories wheras water when it evaporates obsorbs aproximately 600 calories of heat. I guess I need to figure out how much energy is required to lift one gram 800 meters, and convert that to calorie equivalent. But I would think it would still be positive.

    But agreed that the cost of pumping up the water may not have been adaquately worked out in the equation.

  17. This is just an order of magnitude estimate, but they claim that about 100MW will be used to run the plant. It isn’t clear how much of that is going to pumping water up, but 10% seems reasonable.

    That is enough power to move about 1.5kL/s or 400gal/s up 2250 feet
    (m/t=P/gh if you want to check)

    That volume of water has a huge cooling potential.

    The details about the air speed you can achieve from the resulting pressure differential and all of the efficiency considerations are a lot harder to estimate, but the idea is certainly plausible.

  18. Compression would be minimized due to having an exhaust. If anything, it would be at negative pressure due to the change of direction of the flow and subsequent circular expansion (I think. It’s been a long time and a bit of head trauma since fluid dynamics)

  19. Have you ever been to the Rio Grande valley, my friend? Cold days are not a problem. Cold nights will be. It’s near-desert in a lot of it and the air cools rapidly

    Yes, it does have seasonal variability. However

  20. Nobody is considering the dust storm this thing is going to kick up. 175mph winds in an arid desert? What are they going to do to control dust around this thing assuming everything works as planned? The engineers at raccoon mt. stored energy facility(Chattanooga, TN) did not anticipate the currents that would be created when water was released from their facility, sending a few boats into the shore pretty hard. Have they even considered this aspect of the tower?

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