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LowKarmaAccount | 12 years ago

When I was in high school I looked into making a micro-power plant using the Seebeck effect for the Intel Science Talent Search. I thought about using liquid sodium as a heat sink, which is what some heliostats use. Solar power towers use the captured energy to power turbines, but this isn't very efficient, so I thought I would add thermoelectric generators to capture some of the energy that is lost as heat.

I ended up not doing this because the Seebeck effect isn't really a useful power-plant (in the broad sense of the word) when you have a small temperature gradient because it is really inefficient, although it is useful for thermometers and other low power items, and for some exotic things like Radioisotope Thermoelectric Generators, which is what powers Voyager and other long distance spacecraft. It becomes worth using when you have a large, consistent energy source, which is usually geothermal energy. But the small temperature difference between the human body and the flashlight and the low efficiency of thermocouples means that this project won't seriously compete with battery powered flashlights. However, it is a cool idea and could have some niche uses.

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pocketstar|12 years ago

Yup, Seebeck is incredibly inefficient, as for RTG's in space I think they would rather use a Rankine cycle but that would be prohibitively too heavy to launch.

Good on your for using peltiers back in HS. In HS I made a sweet exoskeleton using peltiers for active cooling while outside in the summer heat.

sigkill|12 years ago

>Seebeck is incredibly inefficient

Yep, I was going to try to use that (peltier) in conjunction with a small array of solar panels to cool my car because summer afternoons can get incredibly hot - outside temperature reaches 45C, so I'm reasonably sure the car's interior would reach 55-60 easy. Alas! running some back of the envelope calculations (before jumping into the whole thing) I quickly discovered that I'm better off trying to find an efficient and tiny compressor, and large secondary battery to charge off the solar panels.

This problem still remains unsolved and no, remote start is not an option. I'm trying to craft something that is completely independent of the gas in the tank and preferably self sufficient.

Daniel_Newby|12 years ago

Spacecraft use RTGs for reliability—they have no moving parts. Moving parts kill space missions.