Can entropy production be avoided?
There is a way of avoiding entropy production and that is to transfer the heat via an engine. The figure below shows what happens if the heat is transferred with a Carnot engine. If the work leaves the system, as shown by the left hand side of the figure, no entropy is produced. If the work is allowed to dissipate, as shown on the right hand side of the figure, the internally generated entropy is the same as without the Carnot engine. The engine does not have to be a Carnot engine other ideal cycles can be used. The gravity cycle shown on the figure below accomplishes essentially the same result as a Carnot engine. The cycle is called the gravity cycle because its operation requires gravity; the gas expands as it rises and is compressed as it descends. The operating conditions and the vertical extent of the cycle were selected to make the average temperatures at which heat is received and given up correspond to those in the Osawa et al. entropy budget. Subsiding air is compressed natur
