FINITE-TIME THERMODYNAMIC QUANTITIES OF A TWO-STAGE HEAT ENGINE

Abstract

Two-stage heat engine under the second condition in which the maximum efficiency is set to be ηC and the minimum efficiency(the efficiency at maximum power) is set to be half of ηC; it is effectively optimized. The study investigated the engine under the first and second auxiliary system. In the first stage working substance, the auxiliary system is thermalized with a hot reservoir during which it absorbs some amount of heat from hot reservoir whereas in the second stage, the auxiliary system is thermalized with cold reservoir and releases some amount of heat to cold reservoir; difference of the heat exchange and the dissipation of the operation would give the net work done. By Employing a unified criterion for energy converters, the model of engine is effectively optimized and found to yield optimum finite-time thermodynamic quantities. This used to determine its optimized periods, optimum power and efficiency and re scaled the quantities. Efficiency-wise the optimized efficiency is better than its value at maximum power; however, power-wise the maximum power is greater than the optimized power. In the range of possibilities, the heat engine that optimized to give a figure of merit is greater than one. The plotted against ηC is about 1.22 as ηC 0.5. So >1 and that the optimized mode of operation is better than its maximum mode of operation for the model. Else where, for the entire values of ηC the maximum working condition is better than the optimum working condition for the model of heat engine