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Geothermal Stirling Engine

Magma Heat + Arctic Cold
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One could drill a hole in the Earth near one of the poles far enough to get to the magma. Then he could use the significant heat difference between the magma and the arctic ice to power a huge stirling engine (see link). This would be a very efficient way to utilize geothermal energy.
apocalyps956, Jun 26 2006

stirlingengine.com FAQ http://www.stirling...ope=public&faq_id=1
info on stirling engines [apocalyps956, Jun 26 2006]

[link]






       Funny - I can't think of a less efficient way to utilize geothermal energy in terms of return on investment.
Texticle, Jun 26 2006
  

       Or stick a miniature Stirling cycle engine in your ear and use brain heat to run your cell phone.
ldischler, Jun 26 2006
  

       Yeah, for the seven years of arctic ice we have left.
Galbinus_Caeli, Jun 26 2006
  

       And how do be transmit the power down to the populated areas? (-) But...   

       Skip the ice, just use a parabolic reflector to radiate the heat from the cold end out into intersteller space and run the thing at nigh. That actually works, by the way, you can freeze water with a solar cooker by pointing it up at the empty sky at night.   

       The deepest hole ever dug in the earth was stopped due to extreem heat melting the equipment. That was in the Soviet Union and I seem to remember they made it to 12 or 13 miles. Search diggdot.us for that story. And there are areas where geothermal energy is available near the surface.   

       A low effeciency, long life, stirling or other heat engine might be good in this capacity. Especially since it would generate at night and could be located anywhere.
James Newton, Jun 26 2006
  

       wild guess here, but let's say the hot end is 600C and the cold end is local surface temperature. You want to move thousands of miles away and run cable all that way for a say 30C gain?
BunsenHoneydew, Jun 28 2006
  

       This is good, but instead put it in the ocean in a relatively warm area and use the temperature differential between the warm surface water (say 70 or 80 degrees F) and the very cold deep water (34 degrees F). You could have an insulated tube that transports the warm water from the surface down or the other way around (wherever the stirling engine is). This might be a fairly efficient way to use solar heat.
jmvw, Jul 06 2006
  

       //This might be a fairly efficient way to use solar heat.//
The maximum eff. would be less than 9% if the upper temp. was 80F and the lower 34F. So, not fairly efficient at all.
ldischler, Jul 06 2006
  

       Calculating the Carnot efficiency? I'm shocked - SHOCKED! to find that there is actual SCIENCE going on in this category!   

       Oh yeah, almost forgot : [-]
strange606, Jul 07 2006
  

       [ldischler] In your calculation, did you include the loss of a generator?   

       Keep in mind there is a vast amount of this energy available in the oceans. Even an inefficient conversion has the potential to produce vasts amount of energy.   

       And the byproduct is either local warming of the deep ocean, or local cooling of the surface. This may have some adverse effects, but it's not like we're blowing carbon dioxide into the atmosphere.   

       I think the real problem is that large stirling engines do not exist yet.
jmvw, Jul 07 2006
  
      
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