Air Flow in a 10m. pipe - generating electricity ?

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Discussion Overview

The discussion revolves around the feasibility of generating electricity using airflow in a 10-meter pipe designed to leverage atmospheric pressure differences and temperature variations. Participants explore theoretical and practical aspects of this concept, including potential energy generation methods and existing applications.

Discussion Character

  • Exploratory
  • Debate/contested
  • Technical explanation

Main Points Raised

  • Jonathan proposes a design for a pipe that could generate electricity through airflow created by atmospheric pressure differences due to height.
  • Some participants question the effectiveness of the pipe, arguing that air would flow freely without it, suggesting that the pipe may restrict airflow rather than enhance it.
  • Others support the idea that temperature differences, rather than pressure differences, could drive airflow, especially if the pipe were significantly taller.
  • A participant mentions that solar radiation could heat the pipe, potentially initiating airflow, but notes that the effectiveness may vary with temperature changes at night.
  • There is mention of existing experimental power plants that utilize similar concepts, although the practicality of generating useful amounts of electricity remains in question.

Areas of Agreement / Disagreement

Participants express differing views on the viability of using a pipe for generating electricity through airflow. While some agree on the limitations of the proposed method, others suggest alternative mechanisms like temperature differences. The discussion remains unresolved regarding the effectiveness of the initial concept.

Contextual Notes

Participants highlight assumptions about airflow dynamics, the role of temperature versus pressure, and the practical limitations of the proposed pipe height. There are also references to existing applications that may not directly correlate with the proposed idea.

azoulay
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I have this idea about creating a 10 meter plastic/metal pipe that would go from a house roof to the ground and having a "U' shape close to the ground so that both holes are directed at the sky.

Does anyone have a clue if the difference in atmospheirc pressure between both holes (10 meters difference in heigth) would generate enough of an air flow (in the pipe of course) to make a little dynamo (shafted in the hole close to the ground) generate electricity ?

Regards,
Jonathan
 
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Please ask yourself this: if putting in a pipe would make air flow, why would the air not flow even without the pipe? A pipe is just a restriction to flow.
 
Russ Waters is correct. The open air has no restrictions on its ability to flow other than air pressure. Therefore there would be much more airflow between the two locations without putting a pipe in place than would actually flow through the pipe. So you could generate more energy by putting up an equal number of equally sized dynamos in the open air than you would generate in the pipe.
 
Posts #2 and #3 are right, but this could work not because of pressure difference, but temperature difference. A 10 meter tall pipe would probably be too short, but if you had a pipe the height of a skyscraper, there would be a flow of warmer air from ground level up the pipe. This needs something to get the flow started (otherwise Russ's objection still holds), but solar radiation will heat up the solid pipe faster than the surrounding air during the day, and that is enough to start the air flow. If the pipe cools down faster than the air at night, the flow direction might be reversed.

I don't think anybody has used this to generate "useful" amounts of electricity, generation, but it is used for energy efficient ventilation in tall buildings.
 
AlephZero said:
I don't think anybody has used this to generate "useful" amounts of electricity
There are experimental power plants using this concept.
 
thank you very much for your precise explanations . Very helpful.
 

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