On-line monitoring of power-plant performance, using exergetic cost techniques

Among the possible applications of thermoeconomics, the most promising one is perhaps the diagnosis of the operation of actual energy systems. Diagnosis can be considered as the art of discovering and interpreting signs of malfunction and of quantifying their effects in terms of additional consumption of resources. In the sphere of energy systems a good diagnosis requires: (i) the application of regulatory procedures and performance tests codes, in order to determine the state of the system with precision (clinical diagnosis) and (ii) a good theory which would provide concepts to aid the comprehension and to explain the causes of such a state (etiological diagnosis). The problem to solve can be formulated as follows: where, how and which part of the consumed resources can be saved by keeping the quantity and specifications of the final products constant? This paper briefly explains the thermoeconomic approach to solve this problem and presents a supervisory system running in a 350 MW coal power-plant which uses these ideas to diagnose in real time the causes of heat rate deviations.