Exergy efficiency based multi-objective configuration optimization of energy hubs in the multi-energy distribution system

In the planning of integrated energy systems, energy efficiency analysis is a key indicator for system optimization. However, the previous studies on multi-energy systems mainly focus on economy or environmental benefits, but energy efficiency, especially exergy efficiency is seldom considered. This paper proposes an optimization model and method for energy hubs within multi-energy distribution systems, with a focus on exergy efficiency as one of the key objectives. Initially, the concept of exergy efficiency analysis for multi-energy systems is proposed, along with methods to quantify the performance of energy conversion processes. Subsequently, a multi-objective optimization model is then formulated to minimize exergy efficiency losses while simultaneously balancing exergy efficiency with objectives related to pollutant emissions, investment, and operational costs. Due to model complexity, non-convex terms within the objective function and equality constraints were linearized. Subsequently, a mixed-integer second-order cone programming method was implemented, providing an efficient solution to the optimization problem. Testing on the IEEE 33-bus system, a 24-node gas system, and an energy hub confirms the superiority of the proposed method through case studies, and further corroborates the effectiveness of the proposed model and solution algorithm.