Design and optimization of an exergy-cascaded hydrogen hub with multi-level heat recovery and high-temperature thermal support: Thermodynamic and exergy assessment, mixed-integer linear programming (MILP)-based co-design, and predictive dynamic operation

Abstract

Although prior studies have addressed hydrogen hubs, waste-heat recovery, heat pumps, and multigeneration systems, a unified framework integrating multiple electrolysis technologies, exergy-based thermal allocation, system-level co-design, and dynamic operational validation is still lacking. To address this gap, this study proposes an exergy-cascaded hydrogen hub integrating multi-level heat-pump-assisted low- and medium-temperature heat recovery, thermal storage, and a scenario-level high-temperature thermal support branch for SOEC operation. The low- and medium-temperature branches are modelled as low-to medium-temperature heat-pump-based upgrading stages, whereas the 500–700 °C branch is treated as a technology-neutral high-temperature thermal support pathway rather than as a validated vapor-compression heat pump. Under baseline conditions, the system produces 18.64 kg/h hydrogen, delivers 250 kW district heat and 150 kW high-temperature support, utilizes 237.24 kW of 238.39 kW recoverable heat, and identifies the provision of high-temperature SOEC thermal support as the main exergy penalty.