P. Kuran
Warsaw University of Technology, Warszawa, Poland
S. Sieniutycz
Warsaw University of Technology, Warszawa, Poland
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http://dx.doi.org/10.3384/ecp110571529Ingår i: World Renewable Energy Congress - Sweden; 8-13 May; 2011; Linköping; Sweden
Linköping Electronic Conference Proceedings 57:7, s. 1529-1536
Publicerad: 2011-11-03
ISBN: 978-91-7393-070-3
ISSN: 1650-3686 (tryckt), 1650-3740 (online)
Classical thermodynamics is capable of determining limits on energy production or consumption in terms of the exergy change. However; they are often too distant from reality. Yet; by introducing rate dependent factors; irreversible thermodynamics offers enhanced limits that are closer to reality. Thermodynamic analyses lead to important formulas for imperfect efficiencies. In this paper power limits for generation or consumption of thermal; solar; chemical energy are obtained by application of the optimal control theory.
Power limits define maximum power released from energy generators and minimum work supplied to separators or heat pumps. In this research we consider power limits for both devices of energy generator type (engines and fuel cells) and of energy consumer type (heat pumps; separators and electrolysers). Each process is driven either by a simple heat exchange or by the simultaneous exchange of energy and mass fluxes. We stress the link of these problems with the classical problem of maximum work. Particular attention is devoted to fuel cells as electrochemical flow engines. Amongst a number of new results; notion of certain special controls (Carnot variables) plays an important role. In particular; we demonstrate their role in the analysis of heat and radiation engines; chemical power generators and fuel cells.
Efficiency; power generation; entropy; thermal machines; fuel cells.
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