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steven landau

new york, ny, United States

Design instructor

Member since September 08, 2008

  • is this kind of electricity actually free?


    In response to Pedal to the metal..., posted by oz etzioni,
    in the thread Pedal to the metal...

    Oz, One question that I have about this idea (and others that rely on human energy to produce electricity) is, is it actually free? Doesn't introducing a generator actually make it more difficult to pedal the bike? I can see how it makes sense when the bike is stationary, and the operator is just standing around doing nothing while he waits for the customers to make their calls, but don't forget the first law of thermodynamics, which addresses the conservation of energy. In the Nicaraguan example, kinetic energy (a person pedaling) is converted to electrical energy. So, while it may appear that this is a "free" source of energy, it is not. The person pedaling is a walking power station. Plants absorb energy from the sun, animals eat plants, people eat animals, and muscles burn calories when they move heavy objects. We can correctly think of agricultural fields as giant solar collectors (this process is more direct and obvious when we convert sugar to alcohol and put that in our cars as ethanol, but the laws of thermodynamics still pertain even when the sequence of energy conversions is more complex). So, it seems to me that any system that requires human locomotive power to be converted to electrical energy must take into account the added work that that this equation implies. Of course, if it is possible to only use waste energy, than the economics change. For example, a bicycle that uses a generator to add drag to slow down (instead of applying brakes is truly creating electricity for free (once the cost of the equipment has been paid off). A question I think you should be asking as you study some of these ideas for generating electricity from human activity, is the motion required adding to the person's work load? The US military has developed backpacks that harvest energy produced by the normal cycles of a person walking, but doesn't wearing this backpack actually tire the person out more quickly? I am interested to know what you think of this. steven

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My Interests

  • Industrial Design
  • Environmental Design
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