Modeling and multi-rate simulation of combined heating networks and power to hydrogen with waste heat recovery

Power to hydrogen (P2H) facilitates the utilization of intermittent renewable energy, but it also leads to massive energy losses in the form of heat. Waste heat recovery (WHR) for district heating is a promising way to reuse the heat energy that would otherwise be disposed. However, the combination of heating networks and P2H with WHR for improving the operational efficiency of integrated heating and electrical systems (IHESs) has rarely been considered in the existing literature. To highlight the value and evaluate the dynamic influences of WHR from P2H, this paper proposes a dynamic modeling and multi-rate simulation method for the coupled heating networks and P2H with WHR. Different from previous IHES simulation methods that use steady-state models of electrical systems, the dynamic model of hydrogen production with wind power is developed to reflect the dynamic interaction between heating and electrical systems. To enhance the versatility, the dynamic model of heating networks is established considering variable inlet temperature and mass flows. Moreover, the parallel multi-rate simulation method is proposed to improve the computational efficiency in simulating the dynamic process of heating networks and P2H-WHR, and the multi-rate simulation timestep ratio is designed considering numerical stability. Simulation results indicate that P2H-WHR reduces the energy consumption of heating boilers in heating systems and the proposed dynamic models and parallel multi-rate simulation method capture the dynamic interactions in IHESs accurately and efficiently.