Abstract
Within the context of finite time thermodynamics (FTT) an endoreversible power plant model (the so called Curzon and Ahlborn engine) under thermoeconomical criteria was analysed based on the concepts of profit function and the costs involved in the performance of the power plant. The analysis is made by means of two FTT optimisation criteria: the maximum power regime and the so called modified ecological criterion. The authors calculate the optimal thermoeconomical efficiency under ecological conditions and show how this optimum efficiency reduces the heat rejected to the environment to approximately a half of that rejected to the environment under maximum power conditions.