Procedures for operational optimization of polygeneration systems

The need for more efficient and less pollutant energy systems can be satisfied only through the deployment of proper optimization tools, capable to improve environmental, economic, and social sustainability. In this master thesis are illustrated some procedures aimed at including new functionalities to an optimization tool. XEMS13, the tool under consideration, can be used to optimize the operation of polygeneration systems. In this case, it is able to optimize the production of thermal and electrical energy of a group of selected components, to satisfy the energy demands of a district heating network. The work is divided into two main topics. The first part regards the analysis of the input data of XEMS13. In particular, a clustering procedure is created to derive from the annual thermal demand, a selected number of significant days, which profiles are able to represent the entire annual profile. The scope is to reduce the computational time and improve the accuracy of the simulation of a year. Subsequently, two post-processing codes are realized with the aim to reconstruct, starting from the XEMS13 simulation results of the representative periods, the annual results profiles. The second main topic is the realization of procedures that iteratively run the optimization tool by changing a parameter. The first is a procedure that performs an iterative run for the implementation of white certificates. They are calculated through the result of the simulation and inserted in the successive iteration, by varying the maintenance cost of the cogenerators. The loop continues until convergence is found or a number of maximum iterations is reached. The last routine is able to launch a parametric run, for which the size of one component is repeatedly changed. In the end, the best configuration is displayed. The research showed that it is possible to identify a suitable number of input representative days, able to return accurate annual results and that the external iterative procedures are valid tools for multi-run simulations. These procedures have been realized in cooperation with EGEA S.p.A. firm that kindly provided most of the data present in this master thesis.