Coordinated optimization of a novel integrated energy system considering ground source heat pump, organic Rankine cycle and power-to-gas

Against the backdrop of efforts to achieve "carbon peak" and "carbon neutrality," integrated energy systems (IES) have become an important direction in the development of energy systems due to their advantages of high efficiency, energy saving, and environmental protection. In this paper, a synergistic planning approach for IES considering ground source heat pump (GSHP), organic Rankine cycle (ORC) and power-to-gas (P2G) is proposed. Firstly, this paper constructs a multi-objective planning model for IES that includes ORC, P2G, and GSHP techniques to balance the system's economy, environmental friendliness, and energy efficiency. Subsequently, GSHP heating/cooling ratio, ORC power supply ratio, and direct embedding of P2G are introduced to propose three novel operation strategies (improved following electrical load (IFEL), improved following thermal load (IFTL), and improved following hybrid load (IFHL)). In addition, a novel multi-objective optimizer is proposed to optimize the component sizes and performance of the IES under the proposed different operating strategies. The validity and feasibility of the proposed methodology and operational strategy are verified by analyzing specific cases. The results show that the proposed IES under the operation of IFEL strategy outperforms IFTL and IFHL in terms of improved energy efficiency, reduced operating costs and reduced carbon emissions. Its annual economic cost, energy consumption and pollutant emissions amounted to 979,699.10 $, 10,557,646.34 kWh and 2,389,179.75 kg, respectively. This study not only provides a novel theoretical framework and technical means for the optimization and planning of IES, but also provides an important reference for the development of sustainable energy systems in the future.