| Chilled water plant optimisation is the main theme of this thesis. The objective of the optimisation process is to find the correct sequence of operation of chillers, and of their associated cooling towers, to minimise plant energy consumption.; New models for cross-flow cooling towers and centrifugal chillers are proposed as well as an optimisation method based on genetic algorithms.; The proposed cross-flow cooling tower model is semi-empirical and is based on the &egr;-NTU method. It's main characteristic is that it requires only ten experimental data points as inputs. It is shown that the model can adequately predict the tower thermal performance within 3% of manufacturer's data, over the full operating range.; Due to the complex nature of the operation of a centrifugal chiller, especially at part load condition, an empirical chiller model has been developed. Using the thermodynamic refrigeration cycle as a theoretical basis, experimental data are curve-fitted to obtain the thermal behaviour of the chiller. Validation results show that the model agrees within 5% with manufacturer's data, outperforming other models that were found in the literature.; In the second part of this work, a genetic algorithm is developed to optimise the chilled water plant energy consumption. (Abstract shortened by UMI.)... |
