I found recently the existence of Geothermic Energy and i didn’t really understand It.
There are zones where the underground is so hot we can get energy (Electricity) from it. How?
I read that One of the first to do It was in Italy, in the 1904 or something, and i don’t understand how could they build something without…well die. If the heat is so High wouldnt people be hurt? How could they build something like that? I guess that now is more easy but at that time how was that even possible?
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I’ll point out that in addition to geothermic energy there’s geothermal for the purpose of building conditioning. This is more broadly available and common because you don’t need access to exceptionally hot geothermic activity like a volcano.
In short: As others have pointed out certain regions have easy access to very hot temperatures to create steam to generate electricity but geothermal for building heating and cooling uses broadly available steady mild geothermal temperatures just below the surface. This isn’t used to produce electricity because there’s not enough energy density to make steam which is what’s required to generate electricity. It is however good to use as a heat-sync.
In long: Most air cooling is done by moving heat from an interior space using a refrigeration cycle to the exterior air using electricity. The reverse can be done to heat an interior space by moving heat from the exterior to the interior by reversing this refrigeration cycle. This is done with an indoor unit connected to an outdoor unit with refrigeration piping. This would be called an air cooled system. The refrigeration cycle is doing the work of moving the heat but the final heat sync for that heat is the outside air. One of the drawbacks of this is that outside air varies considerably and usually in the opposite direction of what would be efficient. You’re trying to pump heat from a 70F building to a 80-100F outside air and when you’re trying to heat the building you’re trying to maintain a 70F interior by pulling heat out of the -20F to 60F exterior air.
Instead of an air cooled system you can use a geothermal system. The same refrigeration system is used but instead of using an exterior refrigeration to air heat exchanger you use a geothermal loop to refrigeration heat exchanger. The ground several feet below the surface maintains a fairly constant 50F, water is pumped through loops in this region either by going vertically down hundreds of feet over a small surface area footprint or it can go horizontally in a shallow area taking up a larger land footprint. Now you’re not relying on changing outdoor air temps and fighting up hill against the seasons but using a steady temperature heat sync that’s closer to the temperature you’d trying to maintain indoors. This system is more expensive to impalement than air cooled because you need to either drill wells or a large trench whereas an air cooled system just requires a place to put a condensing unit outside but due to the increased efficiency of the refrigeration cycle having to do less work the geothermal can result in cost savings over time. This tradeoff gets better with scale – might make more financial sense for a large building to implement than a residential single family house. Geothermal also has the added benefit of not needing a mechanical unit outside which helps with aesthetics. A large hotel or university or mansion can put the geothermal unit in the basement or a nice looking out building without needing either a big ugly outdoor unit with noisy fans or multiple smaller ugly boxes with noisy fans.
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