🚀 go-pugleaf

In article <38mkd3$gmm@usenet.rpi.edu>,
William Smythe <smythw@alum01.its.rpi.edu> wrote:
>Am I the first one to notice that the post claims to violate the second law but
>really violates the first law instead or have I just forgotten most of what I 
>learned in thermo. If I remember correctly, it is the first law that states 
>that you need a hot and a cold pole to convert heat to work and which lays
>down the relationship for the ideal Carnot efficicency. The second law on the
>other hand deals with entropy and implies (among other things) that as bad as
>the first law was, you will almost certainly do worse. Generating work from
>heat without a cold resevoir does not primarily concern the second law. 
>
No, the first law is simply the conservation of energy:  it says that the
change in the internal energy of a system must be the sum of the work done
on the system and the heat transferred to the system.  One way of stating the
second law is that you cannot turn the heat present in a system into work,
unless you have a lower-temperature system available.   However, it is true
that there is a "second part of the second law", which says that the work 
available from a system (given some heat reservoir which can be used to 
run thermodynamic cycles) declines over time.  The "first part" of the 
second law is usually thought of in terms of work extractable from 
equilibrium systems, and states that the extractable work ("free energy")
in a thermodynamic cycle is: F = E -Tzero * S, where Tzero is the temperature
of the heat reservoir one has available. (In fact this is true of nonequilibrium
systems too, but that is a controversial claim).  The "second part" concerns
the time evolution of systems, towards equilibrium, and states that the the
extractable work (which the first part of the law tells us is given by
E - Tzero S), never increases over time. (The fact that entropy  S never 
decreases implies this.)  So William has drawn attention to
an important distinction (which often causes confusion when people talk 
about "the" second law), but it is the distinction between two parts of the
second law, not between the second and the first.  It is indeed the first
part of the second law that Schaeffer is claiming to violate, as usual with
such crackpot schemes.

Howard Barnum