The second law of thermodynamic say that entropy of a system always increase or stay constant. So I think sometime, we need some kind of entropy reservoir. Although the normal energy source is also an entropy reservoir, it is not used or created with this idea in mind.
So my question:

  • Do we need a seperate entropy reservoir?
  • If it is necessary, how to build one?
  • $\begingroup$ Why would you need one? If they were needed, we would develop them. What happens in your world to make you want such a thing? $\endgroup$ – Mołot Sep 12 '16 at 8:46
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    $\begingroup$ There is, as yet, insufficient data for a meaningful answer $\endgroup$ – Scott Downey Sep 12 '16 at 8:55
  • $\begingroup$ @ScottDowney that was a cute short story... :) $\endgroup$ – Isaac Kotlicky Sep 12 '16 at 10:43
  • $\begingroup$ We need a "close"option for "impossible according to the laws of nature". $\endgroup$ – MichaelK Sep 12 '16 at 10:49
  • $\begingroup$ I mean some place that is kept in low entropy state, so we can use it to renew the working ability of a system. $\endgroup$ – DTN Sep 12 '16 at 12:20

It is impossible

Entropy is not a physical thing like energy or a substance like water. It is the relationship of configurations of a system before there is a transfer of heat and afterwards. Basically it is a measure of the amount the states in a system have changed. There is no physical substance that can be called entropy. There is nothing to store in a reservoir.

It can also be described as a measure of probability. If entropy is considered as a form of probability, then it is obvious that it is impossible to build a reservoir for probability.

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  • $\begingroup$ +1 on this. Entropy cannot be move about like some thing, or even like heat. If we could store entropy, it would be a heat reservoir. But pumping heat into a reservoir creates... ...wait for it... ... entropy, outside the reservoir. $\endgroup$ – MichaelK Sep 12 '16 at 10:47
  • $\begingroup$ @MichaelKarnerfors. So a heat reservoir stores entropy, but pumping heat into reservoir creates entropy in the rest of the universe. Why we can use the universe as entropy reservoir. Nice edit, by the way. $\endgroup$ – a4android Sep 12 '16 at 13:03
  • $\begingroup$ Well it does not help us because we live in that universe and what OP wanted was to try to get entropy away from us. But as he said: the 2nd law of thermodynamics is not negotiable. We are irreversibly moving towards the Heat Death of the Universe. en.wikipedia.org/wiki/Heat_death_of_the_universe $\endgroup$ – MichaelK Sep 12 '16 at 13:07
  • $\begingroup$ @MichaelKarnerfors That's the paradox of it all: entropy can't gotten away from nor stored. Moving towards the heat death of the universe is hypothetical & controversial. There are problems if entropy can be applied to the universe as whole. Some differences of scientific opinion about heat death of the universe are quoted in the Wikipedia entry. It remains an open question. $\endgroup$ – a4android Sep 12 '16 at 13:52

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