A Multi-Energy Microgrid Modelling and Optimization Method Based on Exergy Theory

Multi-energy system is a promising solution to improve energy efficiency. In this paper, exergy analysis is applied to the natural gas based multi-energy microgrid. The exergy theory is developed on the basis of the second law of thermodynamic. Exergy represents both quantity and availability of energy and exergy is defined by the maximum potential useful work in a certain amount of energy. Multienergy flows of electricity, gas, cooling and heating power are represented by exergy. By applying improved non-dominated sorting genetic algorithm, the pareto front of minimum unit cost of output exergy is reached and the output curves of system are obtained. Simulation results show the usability of exergy theory to multi-energy microgrid and the better energy-saving performance of the microgrid system in comparison to some on-running projects.