Centralized and distributed generation in a district heating system: application of a thermal and fluid-dynamic model for integrate energy network analysis

The aim of this work is to implement and apply a model to evaluate the thermo-fluid dynamic behaviour of district heating networks, with the help of graph theory and SIMPLE algorithm. The purpose of this implementation is to study the feasibility of the substitution of natural gas users with district heating users, in order to study the possibility of an integrate energy network analysis. The first part of the work is dedicated to the numerical implementation, with the help of software Matlab, of the physical problem. A generic network is analyzed, with consequent results and validation of the model. Once the model is validated, it has been applied to a real configuration: a case study of a gas network in an urban area. A substitution of natural gas load for heating with district heating is supposed. The installation of the network is studied in two different configurations: centralized heat generation and distributed heat generation. In the first case a cogeneration plant of 90 MWe is sized, where the heat generated is provided to the district heating network and the electricity generated is sent to the grid. In the second case the power of the cogeneration plant is halved, the supply temperature of the grid is decreased and 21 thermal boosters are applied in strategic nodes. These thermal boosters are linked to the gas network and electricity grid, and here space for an integrate energy network analysis is left. The study ends with the analysis of Carbon Dioxide emissions, primary energy saving and economic analysis of the two installation configurations.