Abstract
The production of work in finite time from a reservoir with finite heat capacity is studied. A model system, for which the only irreversibilities result from finite rates of heat conduction, is adopted. The maximum work obtainable in finite time from such a system is derived, and is found to be strongly dependent upon the reservoir heat capacity. The cycle producing the maximum work is derived for an arbitrary one-component working fluid; no equation of state is assumed. In the optimum cycle, when the working substance is in contact with a finite reservoir, then the temperature of the working fluid is an exponential function of time and the entropy of the working substance is a linear function of time. While the maximum work obtainable in a single fixed-time cycle is a strictly increasing function of the reservoir heat capacity, the efficiency (work produced/heat put in) is a strictly decreasing function of the reservoir heat capacity, for the model system with a finite hot reservoir and an infinite cold reservoir. In the limit where the reservoir heat capacity approaches infinity, the finite-time efficiency approaches the Curzon-Ahlborn efficiency η=1-Tlow0/Thigh0)1/2 for the cycle which produces maximum power.
Original language | English |
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Pages (from-to) | 4721-4727 |
Number of pages | 7 |
Journal | Journal of Chemical Physics |
Volume | 78 |
Issue number | 7 |
DOIs | |
State | Published - 1 Jan 1983 |
ASJC Scopus subject areas
- General Physics and Astronomy
- Physical and Theoretical Chemistry