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Replace solar panels by thermopiles

  1. Feb 17, 2010 #1
    i was thinking- how about replacing solar panels by thermopiles for street lighting and using the sewers as a heat sink. they don't have to be doped and so are cheaper. any reason why this idea hasn't been used before?
  2. jcsd
  3. Feb 17, 2010 #2
    You'd have to have a great sewer. I mean there's this building in downtown Pittsburgh that in the winter you can walk by it and always there is hot steam coming out of the manhole covers on the southwest corner. But other than that I know of no other in Pittsburgh. I'd be willing to bet that in the summer time there is no discharge of heat there though. Oh yes I just read you said for a sink... Herm. In the summertime there's probably a 10 degree difference due to the heat island effect. Again I'll bet it would be picky for the individual sewer. I for one am not keen to go nosing around to find out :) But, I guess if you have the opportunity, go for it :) I'm wondering though, why not just plaster the sink onto the water mains? It seems like you'd get a lot more flow at a more stable, cooler temperature. Wouldn't you have to have a pretty huge thermopile to get the kinda wattage (300 I'd guess?) to drive a street light? I mean at night time the heat differential isn't going to be all that superb. The more humid the environment, the more the atmosphere retains the heat from the daytime, so places like east coast, mid west, and south east are in, arizona and southern california are out. If you ever do make some measurements of the heat differential, and then calculate the size of the thermopile you'd need along with the wattage you're going to need for the light, I'd love to hear the results :)

    Dan K
  4. Feb 20, 2010 #3
    The typical efficiency of a thermopile is quite low even in the most desirable temp range. The cost vs output is also quite high. To be viable, both would have to see very large improvements from present art.
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