Holistic simulation based model of an energy efficient production system : a buffer allocation problem with energy-aware policies

Nowadays one of the most relevant topics in the manufacturing field is the energy efficiency, its improvements are part of one of the last trends in manufacturing, as they could lead to a better use of resources and a consistent cut in the production costs. This way it is surely a key element for the factory of the future, as the whole world relies on new ways of saving energy in order to sustain the planet by emitting less CO2. An interesting and fascinating challenge that companies need to tackle if they want to stay competitive on a market in continuous evolution is to reach the objective of a holistic factory. This thesis starts taking into account two main lines of research, the buffer allocation problem and the energy policies. The study focuses on the analysis of the energy behaviour of a flow line with the aim to find the optimal solution that allows to reach a high throughput without considerable costs. Our methodology is divided into two main parts; the first one is the experiment’s run of all the combinations on a simulation software, and the second one is the performance of a DOE analysis; it involves a multi-objective optimization to find the optimal solution with a statistical approach. We considered six different cases of crescent complexity to test the energy policies that has been created to improve the system energy behaviour. Our research found how an energy policy can decrease the energy consumptions imposing rules on machines’ status. We demonstrate it performing various different cases. At the end, this work allows to increase the energy awareness during a Buffer Allocation Problem. The results obtained were very satisfactory in term of energy and costs reduction. The proposed approach represents a significant contribution to the state of the art, in fact this work has contributed to four fields of research: the energy-saving modelling field; the multi-objective optimization field; the Methods to solve BAPs field; the Real Time Control Infrastructure through IT technologies. The results that this dissertation provides could help the decision-makers of enterprises to be aware of the importance of the context and make evaluations on the possible investments to undertake in order to employ at best the technology available at the moment. Key words: Energy Efficiency; Manufacturing Systems; Energy management; Simulation; Modelling; Buffer Allocation; multi-objective optimization.