Text 30533, 51 rader
Skriven 2009-03-31 01:30:24 av Björn Felten (2:203/2)
  Kommentar till text 30451 av Michiel van der Vlist (2:280/5555)
Ärende: Nuclear power (was: How the US will split)
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 MvdV> Forgive me for being a bit sceptical. If - like Iceland - one has planty
 MvdV> of hot water and it comes free, one does not mind if a substantial part
 MvdV> gets lost in transport.

   You mean pumping it all directly into the ocean is better?

 MvdV> At the university weher I used to work, they had central heating for
 MvdV> several buildings. In winter, when there was snow, one could spot the
 MvdV> location of the buried pipes. No snow there. And that is just
 MvdV> transportng it a few hundred metres...

   Of course there's always losses. But it depends very much on the flow
-- the slower the water runs the more losses you get. And then again,
how many degrees higher do you need the ground to be in the Netherlands
to melt the snow? It's not like you use to have 30 below or something,
rather just around zero, right?

 BF>>    A) by Norway and Sweden (for northern Europe) -- we have enough
 BF>> hydro electricity for all of us if needed -- and

 MvdV> Hmmm.. and will you just give it away?

   Of course not. But I can assure you it will be much cheaper than what
you pay for your kWh at the moment -- I just checked and right now it's
3.68 cent/kWh. How much do you usually pay?

http://www.nordpool.com/en/

 MvdV> although the concept is over a century old, it never really took off.
 MvdV> Must be a reason for that.

   Yes. It has a lousy efficiency as a stand-alone engine, where you add
e.g. 100 units of energy to one side and only get less than 30 units of
work out of it and the rest is waste.

 MvdV> It is bound by the theoretical limittions imposed by the Carnot cycle. I
 MvdV> take it you mean it can operate very near that limit.

   You are making the same mistake as so many others when discussing the
Stirling engine. See above. When you already have the hot water on one
side and the cold return water is not wasted, you *do* get close to 100%
efficiency. Just think about it for a moment: where would all the two
thirds of losses go on a closed system with hot and cold water like this...?

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