Thermoeconomic analysis and optimization of a gas turbine plant combined with an absorption unit

The aim of the paper is to study the performance of a power plant for the combined production of electrical, thermal and cooling thermal energy. The exergy analysis was developed from the system's operating conditions measured in a previous experimental phase, and allowed description and quantification of causes of efficiency loss in the plant. The following thermoeconomic analysis, based on the exergy balance, allowed appraisal of the actual costs of each component and possible optimization of the plant for higher efficiency and cost saving. The thermoeconomic results lead to a better understanding of the influence of off-design operating conditions on the performance of the whole plant and on this basis further improvements and modifications are envisaged. Three modifications of the plant layout are described and discussed, in greater detail for the most promising of them, i.e., compressor inlet air cooling with absorber excess cooling power production. Results show that this solution is particularly effective in the present case, not only from the energetic point of view, but, as is not always the case, also form the economic one. The application of thermoeconomic analysis to the pharmaceutical factory under study has the aim of identifying those components which have the highest cost quantifying losses in cost terms.