Optimization of performance characteristics in a class of irreversible chemical pumps

A new irreversible cyclic model of a class of two-source chemical pumps, which are affected by not only finite-rate mass transfer and mass leak but also the internal dissipation resulting from friction, eddy currents and other irreversible effects inside the cyclic working fluid, is established. By using the optimal control theory, the optimal relation between the coefficient of performance and the rate of energy pumping for the two-source irreversible chemical pump cycles is derived. The maximum coefficient of performance and some other important performance bounds of the cycle are determined. The optimal mass-transfer time, minimum entropy production rate and minimum power input are calculated. Consequently, the influences of the main irreversibilities usually existing in real engineering systems on the performance characteristics of the chemical pump operating between two mass sources are revealed. Moreover, it is expounded that some relevant important conclusions in the literature can be directly deduced from the results in the present paper. (c) 2005 Elsevier Ltd. All fights reserved.