A coordinated approach of multi-energy system considering the off-design characteristics of the devices in energy hub

As essential components in the energy hub, the multi-energy devices are diverse, and their working conditions are complex. The relevant energy efficiency level of devices in the energy hub is also an important factor for the long-term operation of the energy systems. The device efficiency is always considered constant in modeling the energy hub. However, it is necessary to study the efficiency variation and optimization of devices under off-design working conditions. In this paper, we propose a coordinated dispatch method of the multi-energy system considering the device off-design characteristics in the energy hub. The energy efficiency optimization is included in the dispatch process. Then, we use the analysis target cascade (ATC) to obtain the optimal solution. The method is tested in the system, including distribution network, natural gas network, and energy hub. Compared to the traditional method, the proposed method can describe the operation of the whole system more authentically and thereby prove the effectiveness of energy efficiency optimization. The corresponding nonlinear constraints are linearized by piecewise linearization. Besides, we discuss the results of energy efficiency optimization at different load levels and capacity combinations, which is of guiding significance to optimize system working conditions.