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Ohm drill

Geothermal anywhere
  (+5, -2)
(+5, -2)
  [vote for,

After a starter hole has been drilled to get past all the water tables ect, use an ohm drill to drill down to the reqired depth for geothermal energy production.

Here's how it will work. Imagine a circle about 10" diameter, around it are smaller circles which collectively have the same area as the 10" circle, the smaller circles don't touch the big circle but are spaced evenly apart from each other and the big circle, now around the whole thing place another circle also evenly spaced the same distance as the others, the first joint of pipe will have a larger outside diameter for the first foot or so enabling the rest of the pipe to be electrically insulated. this is the cross section of the pipe that will be used.

Now make the pipe out of tungsten so that it is heavier than the surounding rock.

To drill simply pump huge currents into the ground through the small (relativly speaking) area at the end of the drill string, ohmic heating (hence the namesake) causes the ground to melt and the massive weight of the drill then sinks due to displacement of the lighter rock when the total depth has been reached turn off the generators let the ground cool enough to harden or at least wait untill the drill stops sinking may need a large anchor on the bedrock to stop it.

Once it is stopped the power plant can be built over it and the working fluid may then be dropped down the annular holes as it falls the center will fill up with the hotter fluid and heat differential will then be the driving force, as the super heated fluid nears the surface it eventually boils and by the time it reaches the surface it will be all steam moving very fast and can then be used to drive a turbine or if conductive some solid state device. I will leave it up to you to figure out what to power with the now available heat engine.

Additionally since it is a closed system you have more flexability in what you could use as working fluid.

Spaceman Spiff, Feb 20 2009

Rock Melting Technology http://ntrs.nasa.go...2779_1975012779.pdf
Los Alamos Subterrene Program [csea, Feb 20 2009]

Some pix http://images.googl...e=UTF-8&sa=N&tab=wi
Note Tom Swift's early version and fertile ground for whackos. [csea, Feb 20 2009]

Highway to Hell Highway_20to_20Hell
A less slick melty dig. [bungston, Feb 20 2009]


       So, the lava goes where, exactly?
afinehowdoyoudo, Feb 20 2009

       The rock at that depth is rather plastic though not enough to drill through by simply applying weight, the heat generated makes it more plastic if not completly molten and enables the drill to sink. Some of the lava will travel up around the pipe and solidify on contact with cooler rock the rest will push the ground out of the way in the same way that a rock thrown in a pond displaces its volume in water only the viscosity is way higher for rock.
Spaceman Spiff, Feb 20 2009

       how many years until you break even with the initial melting energy?
loonquawl, Feb 20 2009

       See [link] for an overview of rock melting technology, ohmic and nuclear.
csea, Feb 20 2009

       Shouldent be too long since the heat of melting has pretty much nowhere to go, as soon as you start circulating coolant you get back a lot of the energy that went into the progect.
Spaceman Spiff, Feb 20 2009

       Tom Swift. Boy, that takes me back. Now I've dated myself.
normzone, Feb 20 2009

       I like it. It would be good if the pipe trailing behind the heavy drillhead could be something with a little flexibility. It would need to be heat resistant too.   

       These things could be placed anywhere. Instant geothermal. No moving parts. If it stops working, abandon it - no cleanup. If we can avoid angering the Mole People its free energy paradise for us surface dwellers from here on!
bungston, Feb 20 2009


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