On the accuracy improvement of thermoeconomic diagnosis through exergy disaggregation and dissipative equipment isolation

Thermoeconomics join the concepts of Economics and Thermodynamics in order to describe the cost formation process of the overall thermal system. It has great applicability in product cost allocation, optimisation, and diagnosis, aiming to reduce operating costs and to prove a system’s economic feasibility. Thermoeconomic diagnosis is applied to identify the source of extra fuel consumption in each system element. In this study, a power generation system and a heat pump, each with different simulated anomalies, are evaluated by five distinct thermoeconomic models based on productive diagrams (E, E&S, H&S, UFS and UFS+) combined with the fuel impact formula, focusing on its efficiency to quantify the effects of each malfunction with the presence of a dissipative component. For the power generation, the H&S and UFS models presented satisfactory results in correctly identifying the faulty component, whereas, in the heat pump system, the fictitious unities from the productive diagram interfered with the results, inhibiting the determination of the element with an intrinsic fault. Moreover, the UFS and UFS+ models were able to isolate all equipment in the productive diagram for the latter system. •E and E&S models were not adequate for thermal diagnosis.•Multiple faults malfunctions values are the sum of its single faults values for the Power generation.•H&S and UFS are the first able to isolate the components in the two studies, respectively.•Fictitious unities in the productive diagram are masking the identification of faulty parts.