Power-to-fuel technologies provide a promising pathway for long-term energy storage, but existing studies primarily focus on fuel production while overlooking the coordinated storage, transport, and reconversion of energy within integrated energy systems. In addition, the influence of fuel composition and carbon circulation on system-level performance has received limited attention. This study proposes and evaluates a large-scale seasonal energy storage system integrating a reversible solid oxide cell (rSOC) system with the natural gas grid to enable power-to-fuel-to-power conversion and flexible carbon circulation. The rSOC system provides bidirectional energy conversion, while the natural gas grid is repurposed as a multifunctional infrastructure for energy storage, and gas transport through the co-injection of CH4 and CO2. A two-layer optimization framework is developed to jointly optimize system sizing and annual operation while accounting for the spatiotemporal dynamics of the gas grid. Results show that, under the baseline scenario, the proposed system achieves a maximum round-trip efficiency of 41.2%, while membrane-assisted gas composition regulation reduces the levelized cost of storage (LCOS) from 1 USD⋅kWh-1 to 0.85 USD⋅kWh-1. Sensitivity analysis further demonstrates that the proposed operating strategy remains robust under varying renewable energy mixes, maintaining a stable renewable curtailment rate of 6% and annual gas-grid mass-flow deviations of less than 4% over the annual operating cycle. These findings demonstrate the potential of the proposed rSOC system integrated with existing natural gas infrastructure to provide economically viable seasonal energy storage while enhancing sector coupling in future low-carbon energy systems.
With the large-scale integration of renewable energy and the advancement of carbon neutrality goals, water electrolysis has emerged as a pivotal technology for clean energy conversion and storage. As a critical power supply unit for electrolyzers, the performance of rectifier systems significantly influences the efficiency, stability, and operational lifespan of hydrogen production systems. This paper presents a comprehensive and systematic review of five mainstream rectifier topologies for water electrolysis applications: uncontrolled/phase-controlled rectifiers, cascaded rectifiers, fully controlled rectifiers, hybrid rectifiers, and modular rectifiers. The review encompasses their development status, topological structures, control strategies, and technical characteristics. First, an in-depth analysis of each topology's circuit configuration and control methods is provided, covering the phase-shifting transformer architecture of rectifiers, the two-stage coordinated control of cascaded rectifiers, the high-frequency PWM modulation of fully controlled rectifiers, the main-auxiliary channel coordination in hybrid rectifiers, and the hierarchical control in modular rectifiers. Subsequently, a comprehensive comparative evaluation is conducted using 11 key metrics derived from three performance dimensions: electrical performance, economic reliability, and load adaptability. This quantitative analysis elucidates the performance disparities among topologies, identifies their respective application scenarios, and presents typical industrial case studies. Furthermore, the existing technical bottlenecks of each topology are summarized. Finally, future development trends are prospected, focusing on deep hybrid topology integration, intelligent control strategies, modular design, and the application of wide-bandgap semiconductor devices. This review aims to provide theoretical guidance and engineering references for topology selection, optimized design, and technological advancement of high-power rectifier systems for green hydrogen production.
Against the backdrop of intensifying global climate change, traditional building envelopes are constrained by their lack of environmental perception and dynamic regulation capabilities, leading to thermal management shortcomings including heat accumulation, insufficient buffering against thermal shocks, and sluggish response to heat loss transients. Bio-inspired dynamic thermal response technologies offer a promising pathway toward adaptive building envelopes. This paper reviews recent advances in three bio-inspired thermal management strategies. The first involves radiative cooling techniques that mimic biological sensing of external stimuli to regulate spectral properties through molecular vibration and scattering mechanisms. Bio-inspired radiative materials achieved solar reflectance up to 99.6% and surface temperature reductions of 3-10 °C. The second covers thermal insulation and buffering techniques that replicate hierarchical porous architectures found in nature, with thermal conductivities as low as 0.008 W/(m·K) and thermal-resistance switching ratios exceeding threefold. The third focuses on thermal storage regulation techniques that leverage biological topological networks to enhance heat storage density and the dynamic charging/discharging response of phase-change materials, reducing melting times by 45.9%-96.0% while maintaining energy-storage densities of approximately 122-158 kJ/kg. A quantitative multi-dimensional evaluation covering dynamic thermal response, environmental stability, and cost-effectiveness reveals that the synergistic integration of these three bio-inspired strategies enables buildings to achieve all-season, low-energy, adaptive performance gains. Finally, the challenges impeding large-scale fabrication and long-term stability are outlined, and an adaptive thermal management framework integrating artificial intelligence is envisioned, providing a systematic pathway from mechanistic understanding to engineering implementation for dynamically responsive energy-saving buildings.
