swansont Posted October 25, 2021 Posted October 25, 2021 https://www.fastcompany.com/90687369/this-ingenious-wall-could-harness-enough-wind-power-to-cover-your-electric-bill Quote Doucet has built a prototype for a single spinning rod and run simulations based on that. The average annual electricity consumption for an American home uses a little over 10,000 kilowatt-hours per year. One of these walls would be enough. But where Doucet sees true potential is in larger-scale commercial buildings and even cities. “Instead of the typical retaining walls along roads and freeways, you’d have an array of these,” says Doucet, who says he’s in conversation with several manufacturers to help him bring the product to market. I've run across art projects that pretended to be science over the years and didn't stand up to scrutiny, and this has a faint whiff of that given the lack of any detailed analysis. But it's an intriguing idea 20 mph wind is about 600 Watts/m^2 so even if you are only harvesting 10% of that energy, a 10m^2 wall gives you 600 W of electricity. 24 hours of that per day gives you 14.4 kWh, which is only about half of what's claimed, but my assumption of only harvesting 10% of the energy could be too low*. Seems like the ballpark is that the device could be legit. If people are looking into making it, it probably means there's something there. *Betz's law places the maximum at just under 60%. Utility scale systems are something like 45% efficient. I don't know what something like this wall clocks in at
MigL Posted October 25, 2021 Posted October 25, 2021 From the description I would think it would not be very efficient as a 'wall' of your typical suburban home because of the close proximity of other houses, however I can see whole fencelines of these generators encircling suburban properties as an alternative to ( or, in addition to, for those sunless windy days ) roof mounted solar panels. They don't look too bad as a fence.
mistermack Posted October 25, 2021 Posted October 25, 2021 Anything at ground level would have the problem of children and animals getting caught up in the mechanism, unless there was some sort of ratchet system included and other safety features. And small scale usually means big maintenance bills and higher overheads. I personally don't have a problem with big wind generators on land. They don't strike me as ugly. Quite the reverse in fact, compared to the pylons that carry the wires they actually look quite nice to me.
swansont Posted October 25, 2021 Author Posted October 25, 2021 14 minutes ago, mistermack said: I personally don't have a problem with big wind generators on land. You can't put those in your back yard
mistermack Posted October 25, 2021 Posted October 25, 2021 9 minutes ago, swansont said: You can't put those in your back yard There are loads of vertical axis wind turbines on the market which you can already put in your back yard. The article describes this as "ingenious", but all it is is an array of existing technology, with the apprarent disadvantage of no escape mechanism for the wind once it passes through, if it's up against a wall as pictured. You don't see many people using the existing technology, and I don't see where this would have any advantage over what's already out there. It has a lot more moving parts than a single turbine.
swansont Posted October 25, 2021 Author Posted October 25, 2021 1 minute ago, mistermack said: There are loads of vertical axis wind turbines on the market which you can already put in your back yard. The article describes this as "ingenious", but all it is is an array of existing technology, with the apprarent disadvantage of no escape mechanism for the wind once it passes through, if it's up against a wall as pictured. It's not up against the wall. The shadow shows this. 1 minute ago, mistermack said: You don't see many people using the existing technology, and I don't see where this would have any advantage over what's already out there. It has a lot more moving parts than a single turbine. I imagine aesthetics is part of that.
MigL Posted October 25, 2021 Posted October 25, 2021 And simple wire mesh ( chicken wire ) would keep small animals and children out of the spinning vanes. If one or two of the generators are stopped, it would not affect the function of the rest.
mistermack Posted October 25, 2021 Posted October 25, 2021 5 minutes ago, swansont said: It's not up against the wall. The shadow shows this. As pictured, the wall would cause backup of pressure and ruin the efficiency. Even free standing, it's likely that having the individual turbines so close together would greatly reduce their efficiency due to turbulence downwind. Even turbines at sea need a good gap between them to maximise the output. 1
studiot Posted October 25, 2021 Posted October 25, 2021 1 hour ago, swansont said: But it's an intriguing idea Agreed. But from the article. Quote “Wind is always there.” Nonsense. Even in the windiest place on Earth there are periods of calm. But why stand it on the ground ? A good safe place might be built into the gable end under a pitched roof. Or simple erected on top of a flat roof. Wherever it is placed there would need to be a store capable of holding the a predicted numbers of days usage in calm weather. In the UK building codes have maps showing isopleths that could be used for design purposes, as they already are for structural purposes. Final thought. What happens when they ice up ?
MigL Posted October 25, 2021 Posted October 25, 2021 10 minutes ago, studiot said: Final thought. What happens when they ice up ? You get no power until the vanes thaw ? What happens to solar panels when they are covered in snow ( I live in Canada ) ? What happens to a regular wind turbine when its generator needs servicing at 75 metrers height ( I have a 15 ft ladder ) ?
studiot Posted October 25, 2021 Posted October 25, 2021 4 minutes ago, MigL said: You get no power until the vanes thaw ? What happens to solar panels when they are covered in snow ( I live in Canada ) ? What happens to a regular wind turbine when its generator needs servicing at 75 metrers height ( I have a 15 ft ladder ) ? A climate activist cycles out to fix it. https://www.thenational.scot/news/19667986.stunt-cycling-star-danny-macaskill-wind-turbine-challenge-climate-change/
MigL Posted October 25, 2021 Posted October 25, 2021 You can't cycle up a 75 meter high turbine 😀 . Especially the off-shore ones 😄 😄 .
mistermack Posted October 25, 2021 Posted October 25, 2021 30 minutes ago, studiot said: Final thought. What happens when they ice up ? Don't be silly. Ice will soon be a thing of the past. Except in your freezer. Children born today will have to have ice and snow explained to them using old video footage.
Danijel Gorupec Posted October 25, 2021 Posted October 25, 2021 Boh. Microgeneration... what is the most successfull microgeneration technology today? I only know roof solar; is there anything else? Those walls seem to be intended as a microgeneration technology... but I am afraid microgeneration is loosing the battle in the green battlefield. Bigger and bigger wind turbines are winning. Once we completely switch to green power, turbines might become monstrous. Solar plants too... If microgeneration ever becomes an important contributor, the ground-breaking discovery will not be how the energy is produced, but how we managed to network all this together into a smooth and efficient business. Sorry for the blues.
MigL Posted October 25, 2021 Posted October 25, 2021 21 minutes ago, mistermack said: Children born today will have to have ice and snow explained to them using old video footage. Come to Canada; no explanation needed.
exchemist Posted October 25, 2021 Posted October 25, 2021 3 hours ago, swansont said: https://www.fastcompany.com/90687369/this-ingenious-wall-could-harness-enough-wind-power-to-cover-your-electric-bill I've run across art projects that pretended to be science over the years and didn't stand up to scrutiny, and this has a faint whiff of that given the lack of any detailed analysis. But it's an intriguing idea 20 mph wind is about 600 Watts/m^2 so even if you are only harvesting 10% of that energy, a 10m^2 wall gives you 600 W of electricity. 24 hours of that per day gives you 14.4 kWh, which is only about half of what's claimed, but my assumption of only harvesting 10% of the energy could be too low*. Seems like the ballpark is that the device could be legit. If people are looking into making it, it probably means there's something there. *Betz's law places the maximum at just under 60%. Utility scale systems are something like 45% efficient. I don't know what something like this wall clocks in at 20mph is quite a strong breeze, for a city house. 10mph would be a more realistic average, I should have thought, judging by the daily wind speeds in London weather forecasts at least. Which presumably reduces the power by a factor of 4.
swansont Posted October 25, 2021 Author Posted October 25, 2021 1 hour ago, MigL said: You can't cycle up a 75 meter high turbine 😀 . Not with that attitude, at least. 39 minutes ago, Danijel Gorupec said: Boh. Microgeneration... what is the most successfull microgeneration technology today? I only know roof solar; is there anything else? Those walls seem to be intended as a microgeneration technology... but I am afraid microgeneration is loosing the battle in the green battlefield. Bigger and bigger wind turbines are winning. Once we completely switch to green power, turbines might become monstrous. Solar plants too... Unless the energy grid gets updated (the US is generally in bad shape), there will be problems with utility-only generation if electrical demand goes up, as it likely will with the adoption of electric vehicles.
studiot Posted October 25, 2021 Posted October 25, 2021 1 hour ago, mistermack said: Don't be silly. Ice will soon be a thing of the past. Except in your freezer. Children born today will have to have ice and snow explained to them using old video footage. No one is being silly. My heat pump vanes can quite easily ice up when there is no snow or ice about, due to quite low speed air movements through them. 1 hour ago, Danijel Gorupec said: Boh. Microgeneration... what is the most successfull microgeneration technology today? I only know roof solar; is there anything else? Those walls seem to be intended as a microgeneration technology... but I am afraid microgeneration is loosing the battle in the green battlefield. Bigger and bigger wind turbines are winning. Once we completely switch to green power, turbines might become monstrous. Solar plants too... If microgeneration ever becomes an important contributor, the ground-breaking discovery will not be how the energy is produced, but how we managed to network all this together into a smooth and efficient business. Sorry for the blues. Microgeneration. Yes, that is why the diameter of these huge wind tubine rotors is so large. I wonder how thick the 'wall' need to be to generate any electricity from any reasonable wind speed, after overcoming friction of course.
mistermack Posted October 26, 2021 Posted October 26, 2021 This actually is pretty much a non-story, in reality. It has no new invention involved, it's just a rack of vertical axis wind turbines, of which there is already a plethora. Siting them so close to each other could be a unique feature, but only because it would impair efficiency. There's a reason why designers don't pack turbines into a small space, they need an unrestricted flow around them. That's why the big efficient ones have only three vanes, rather than thirty. The story isn't actually what it appears. The gif seems to be computer generated, the shadows are all wrong. And the article says : " Doucet has built a prototype for a single spinning rod and run simulations based on that." So what he's done seems to be to rig up a single unit and extrapolated from that. Hardly an industry shaking event. He says he's "in conversation" with manufacturers. That probably means he's phoned them. Most would laugh at him. There nothing patentable in what's shown in the article. He's actually got nothing to sell. Putting 25 in a line isn't an invention, it's just an inefficient arrangement.
studiot Posted October 26, 2021 Posted October 26, 2021 10 minutes ago, mistermack said: This actually is pretty much a non-story, in reality. It has no new invention involved, it's just a rack of vertical axis wind turbines, of which there is already a plethora. Siting them so close to each other could be a unique feature, but only because it would impair efficiency. There's a reason why designers don't pack turbines into a small space, they need an unrestricted flow around them. That's why the big efficient ones have only three vanes, rather than thirty. The story isn't actually what it appears. The gif seems to be computer generated, the shadows are all wrong. And the article says : " Doucet has built a prototype for a single spinning rod and run simulations based on that." So what he's done seems to be to rig up a single unit and extrapolated from that. Hardly an industry shaking event. He says he's "in conversation" with manufacturers. That probably means he's phoned them. Most would laugh at him. There nothing patentable in what's shown in the article. He's actually got nothing to sell. Putting 25 in a line isn't an invention, it's just an inefficient arrangement. Perhaps you should revise your aerodynamic theory ? With laminar flow there is no interference between the units. A lot of smaller units have the advantage over one big one in the event of a unit breaking down / needing servicing electricity supply is hardly interrupted. One big one is an 'all your eggs in one basket' situation.
mistermack Posted October 26, 2021 Posted October 26, 2021 16 minutes ago, studiot said: With laminar flow there is no interference between the units. What has that got to do with wind turbines? In any case, the vertical axis design is inherently enefficient in extracting energy, however you pack them in. Wikipedia says this : However, these designs produce much less energy averaged over time, which is a major drawback.[26][33] Vertical turbine designs have much lower efficiency than standard horizontal designs.[34] The key disadvantages include the relatively low rotational speed with the consequential higher torque and hence higher cost of the drive train, the inherently lower power coefficient, the 360-degree rotation of the aerofoil within the wind flow during each cycle and hence the highly dynamic loading on the blade, the pulsating torque generated by some rotor designs on the drive train, and the difficulty of modelling the wind flow accurately and hence the challenges of analysing and designing the rotor prior to fabricating a prototype.[35]
studiot Posted October 26, 2021 Posted October 26, 2021 5 minutes ago, mistermack said: What has that got to do with wind turbines? In any case, the vertical axis design is inherently enefficient in extracting energy, however you pack them in. Wikipedia says this : However, these designs produce much less energy averaged over time, which is a major drawback.[26][33] Vertical turbine designs have much lower efficiency than standard horizontal designs.[34] The key disadvantages include the relatively low rotational speed with the consequential higher torque and hence higher cost of the drive train, the inherently lower power coefficient, the 360-degree rotation of the aerofoil within the wind flow during each cycle and hence the highly dynamic loading on the blade, the pulsating torque generated by some rotor designs on the drive train, and the difficulty of modelling the wind flow accurately and hence the challenges of analysing and designing the rotor prior to fabricating a prototype.[35] Apart from fan heaters designed by marketing departments just so they can offer something differenct, most are of the of the cylindical type. Mount a series of these one one top of the other with their axes vertical if you must and you have a ready made wall of generators that does not disturb the airflow in the way an airofoild blase does. Aerofoils produce jets, which involve turbulence. The energy of turbulence air is not avialable for extraction. If mounted one behing the other in the airstream obviously the each succeeding genertor, however it is mounted, will suffer reduced performance relative to its predecessor since the predecessor reduces the wind speed somewhat. That is where the energy comes from. It is recovery from this reduction of windspeed that requires the spacing of the turbines. As I understand the proposal the 'turbines' are of the vertical axis cylinder type, mounted one deep in the wall so this effect will not be evident. The main reason for the lower efficiency of vertical axis machines is that the diameter that can be supported is limited substantially compared to horizontal axis machines. And it is the diameter of the tip that determines the maximum speed and therefore output. I have already mentioned this in a previous post.
mistermack Posted October 26, 2021 Posted October 26, 2021 I see no linked support for any of that. The proof of the pudding is in the eating. Where are all the vertical axis turbines? I see plenty of the popular horizontal units, including investments in the hundreds of millions. One obvious problem with vawts is that while one side is moving with the wind, the other side is working against it. You can mitigate that, with streamlining the shape, but it never goes away, and of course, it's causing turbulence the whole time.
Doogles31731 Posted October 26, 2021 Posted October 26, 2021 I see it as an interesting concept that would suit many locations in the world. For reliable use, you would need good battery storage of course. South Australia has a high percentage of solar and wind, but there were a couple of days when there was neither sun, nor wind, and the interstate supply of coal-powered broke down. Cost /effectiveness may be an issue. New installers would have to assess how long the new units last, seeing that there are so many moving parts. I would be sitting on my hands on this sort of technology for a decade or so till all of the many possible inherent problems are realized and solved. Wind and dust may be a bad combination. I'd wait and observe. New toys mostly work at the start.
studiot Posted October 26, 2021 Posted October 26, 2021 9 hours ago, mistermack said: I see no linked support for any of that. The proof of the pudding is in the eating. Where are all the vertical axis turbines? I see plenty of the popular horizontal units, including investments in the hundreds of millions. I gave you the Physics, what problem do you have with it and why have you not taken on board what I have said several times about diameter ? 9 hours ago, mistermack said: One obvious problem with vawts is that while one side is moving with the wind, the other side is working against it. You can mitigate that, with streamlining the shape, but it never goes away, and of course, it's causing turbulence the whole time. Yes, but you can shield against this effect, which you would need to do anyway as you do not want the rotor to be driven backwards in certain winds. In a wall such as this vertical axis rotors loose their principal advantage that their operation is independent of wind direction. In the extreme they would not work at all with a wind blowing parallel to the wall. So like all systems they concept has attractions and drawbacks which must be balanced against each other. I'm trying to be even handed here and keep an open mind.
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