Search Results (396)

The residential sector accounts for a significant portion of global energy demand, which can be met through sustainable alternatives such as solar energy. This study evaluated the energy, exergy, environmental, and exergy-sustainability performance of three waste heat recovery configurations (double-loop organic Rankine cycle—DORC, Kalina cycle—KC, and organic Rankine cycle—ORC) coupled to a supercritical CO₂ Brayton cycle with intercooling and reheating, designed to meet the demand of a residential complex of 120 homes in the Colombian Caribbean region, built with four different materials, using a concentrated solar power tower as the heat source. Mass, energy, and exergy balances were performed, along with a life cycle analysis, sizing the systems to supply a cooling load of 133 kW. The results show that the three configurations meet the required demand, with energy efficiencies above 50%: sCO₂-DORC (51.7%), sCO₂-ORC (51.61%), and sCO₂-KC (51.32%), with a maximum exergy efficiency for sCO₂-DORC (24.3%). The environmental analysis indicates that the construction phase accounts for more than 95% of total emissions. Overall, the results confirm the viability of these configurations for residential applications, promoting the integration of renewable energies and supporting the regional energy transition. Full article

Reproducing SM4 (GB/T 32907-2016) hardware-accelerator results on open-source RISC-V platforms is difficult, because most published designs depend on proprietary FPGA toolchains. This paper contributes an asymmetric dual-channel SM4 architecture together with a fully reproducible open-source verification framework; physical on-board acceleration is not claimed and is left as future work. The architecture exploits two algorithmic symmetries of SM4—encryption and decryption differ only in round-key order, and the round transform T shares the byte-wise S-box $\tau$ with the key-expansion transform $T^{\prime }$—but maps them onto an asymmetric workload. Bulk encryption is throughput-bound, whereas key expansion runs once per session. Accordingly, a 32-stage fully unrolled encryption pipeline (one 128-bit block per cycle in steady state) is paired with a single round function reused iteratively for the key schedule, and encryption and decryption share one datapath via round-key reversal. Because the TH1520 SoC on LicheePi 4A does not expose the Xuantie C910 RoCC port, we verify the design in three reproducible tiers on the board itself: (T1) RTL co-simulation of an sm4_rocc wrapper passes 1040/1040 vectors for both the standalone datapath and the full system. (T2) A pure-C reference model passes 10/10 GB/T 32907-2016 vectors on the real C910 at a measured 291.9 Mbps. (T3) A Linux illegal-instruction trap-and-emulate prototype confirms ISA and OS-level semantics. Open-source synthesis (Yosys + SkyWater Sky130) gives a measured area of 133 kGE and a switching-dominated post-synthesis power estimate of ≈0.28 W at 100 MHz (≈22 pJ/bit, ≈46 Gbps/W). At 100 MHz the unrolled pipeline reaches an RTL simulation-equivalent steady-state throughput of 12.8 Gbps, about 43.9× the software baseline. Every reported number is reproducible with open-source tools only (Icarus Verilog, GTKWave, GCC, Yosys, Sky130 PDK). Full article

Namibia’s rural communities continue to experience limited and unreliable electricity access despite the potential of the country’s exceptional solar, wind, and biomass renewable energy resources. Conventional grid extension remains financially and technically impractical for dispersed off-grid settlements, underscoring the need for cost-effective, renewable-based alternatives. This paper presents a resource-driven design and multi-objective optimization framework for Hybrid Renewable Energy Systems (HRESs) tailored to Namibia’s off-grid communities. The proposed model integrates solar PV, wind turbines, biomass generators, and hydrogen-based fuel cells with a hybridized energy storage consisting of batteries, supercapacitors, and hydrogen tanks. Using the Non-dominated sorting Genetic Algorithm-II (NSGA-II), the system simultaneously minimizes Total Life Cycle Cost (TLCC), Levelized Cost of Electricity (LCOE), Loss of Power Supply Probability (LPSP), carbon dioxide (CO₂) emissions, and Wasted Renewable Energy (WRE). The framework is applied to three rural villages, Oluundje, Ombudiya, and Onguati, using high-resolution, site-specific renewable resource datasets and community-level load forecasts. The results demonstrate that resource-aligned configurations substantially improve system reliability (up to 99.28%), reduce LCOE (0.0023–0.0811 USD/kWh), and optimize dispatch behaviour across seasonal variations. Storage hybridization further enhances stability by balancing transient and long-duration deficits. Compared to existing diesel mini-grids, the optimized HRESs achieve markedly superior techno-economic and environmental performance. The proposed framework offers a scalable, adaptable, and policy-ready tool for accelerating sustainable rural electrification in Namibia. Full article

A low-latency, low-complexity digital demodulator is presented for chirp spread spectrum (CSS)-modulated RF packets targeting low-power IoT wireless systems operating in spectrally congested environments. Conventional CSS receivers rely on fast-fourier transform (FFT)-based synchronization and long preamble sequences, resulting in increased latency and computational complexity. To address these limitations, the proposed receiver employs amplitude-domain synchronization using oversampled sub-chirp windows and maximum likelihood estimation without requiring FFT processing. A digital demodulator co-designed with receiver’s fractional-N phase-locked loop (PLL) architecture enables rapid sub-chirp generation and fast frequency settling, while compensation techniques mitigate symbol boundary offset (SBO) error due to PLL non-idealities during synchronization. The proposed system achieves packet synchronization within 17.5 preamble symbol cycles while maintaining symbol boundary offset estimation error below ±1%. Simulation results demonstrate a syncword misdetection probability below 10⁻³ at SNRs of 9 dB and 1 dB without and with 8× repetition, respectively. In the presence of interferences, the receiver tolerates worst-case in-band signal-to-noise ratio (SIR) levels down to −16.2 dB while consuming 877 µW and 830 µW average power at the digital demodulator, and fractional-N PLL, respectively. Implemented in 65 nm CMOS, the proposed architecture occupies 0.195 mm² active area. Full article

Considering that conventional heavy-duty mining trucks equipped with centralized drive systems suffer from low transmission efficiency and limited flexibility in power distribution, this study focuses on distributed independent-drive heavy-duty mining trucks and develops energy-saving control strategies from two perspectives: drive torque control and regenerative braking. For the drive torque control, based on the principle of optimal driving efficiency, the overall efficiency of the drive motors is selected as the objective function, and an adaptive genetic algorithm (AGA) is employed to optimize the torque distribution coefficients among the axles offline. For regenerative braking, a fuzzy-control-based electromechanical braking distribution strategy and a dynamic-load-based inter-axle braking force allocation strategy are proposed. Finally, a co-simulation was conducted using MATLAB/Simulink and TruckSim based on specific open-pit mining conditions. Compared with the conventional baseline without energy-saving control, the simulation results demonstrate that under the single-cycle operation, the proposed strategy increases the driving energy utilization rate by 5.69% and achieves a braking energy recovery rate of 39.41%. Furthermore, under the full-mine cyclic operation, the proposed strategy extends the vehicle’s operational duration on a single charge by 200%. These findings demonstrate the strong potential of the proposed strategy to improve overall driving efficiency and fully exploit the regenerative braking capabilities of heavy-duty mining trucks, thereby providing theoretical support for enhancing their economic efficiency and driving range. Full article

Alkaline nickel zinc batteries feature high safety, low cost and eco-friendly characteristics, making them highly promising for large-scale energy storage deployment. However, their practical application is severely constrained by the cathode’s electrical conductivity, available active sites, and cycling stability. Herein, vertical 2D hierarchical flake-like NiCoS_x arrays were in situ grown on nickel foam (NF) via a facile alkali-free solvothermal and in situ sulfidation approach. This highly interconnected and open porous flaky structure significantly shortens the ion diffusion pathways, exposes abundant redox-active sites, and accelerates electron transport, imparting excellent rate performance and superior long-cycle stability to the material. The optimized NiCoS_x/NF electrode achieves a high specific capacity of 323 mAh g⁻¹ at 0.5 A g⁻¹, along with excellent capacity retention capability. Assembled with a commercial Zn anode, the NiCoS_x/NF//Zn full battery delivers 124 mAh g⁻¹ at 3 A g⁻¹, and maintains 112.5% of the initial capacity after 500 cyclic tests. Moreover, the assembled NiCoS_x/NF//Zn full cell possesses a high energy density of 615.2 Wh kg⁻¹ along with a power density of 38.6 kW kg⁻¹ (based on the mass of positive electrode active materials). This unique vertical 2D open hierarchical structure plays a crucial role in enhancing the electrochemical performance of cobalt sulfide cathodes and provides valuable insights for the design of high-performance alkaline zinc-based battery electrodes. Full article

Hydrogen oxy-combustion with high CO₂ dilution is a key component of supercritical CO₂ (sCO₂) power cycles, such as the Allam cycle, enabling high-efficiency, near-zero-emission power generation with integrated carbon capture. However, combustion behavior under high-CO₂ conditions remains insufficiently characterized, particularly with respect to mixing and flame stability. In this study, hydrogen combustion in an O₂–CO₂ environment was investigated experimentally and numerically using a custom-designed multi-hole burner. The experiments were conducted in a 1-bar combustion chamber, while the inlet pressures of the reactants were varied between 10 and 50 bar to isolate the effect of injection conditions. Numerical simulations were performed to analyze flow, mixing, and flame structure. The results show that increasing inlet pressure leads to a more compact and localized flame, despite reduced velocity levels in the combustor due to increased reactant density. Higher inlet pressures result in increased peak temperatures but lower mean combustor temperatures, indicating more intense but spatially confined heat release. The flow field remains structurally similar across cases, while reduced radial spreading and longer residence times influence combustion behavior. Stable flame operation was achieved over a wide range of conditions, demonstrating the feasibility of hydrogen oxy-combustion under high CO₂ dilution. The combined experimental and numerical analysis provides insight into the interplay between injection conditions, mixing, and reaction rates in highly CO₂-diluted hydrogen combustion. The obtained results support the development of compact and stable direct-fired combustors for next-generation supercritical CO₂ power cycles and hydrogen-based low-emission energy systems. Full article

This paper investigates the energy recovery potential of LNG cold energy using cryogenic binary cycles. The thermoeconomic performance of single-, two- and three-stage Organic Rankine Cycle (ORC) configurations across different working fluids and LNG regasification capacities has been evaluated. The analysis shows that ORC-based LNG cold energy power units achieve specific net power outputs of 45–55 kW/(kg_LNG/s) for single-stage, 74–83 kW/(kg_LNG/s) for two-stage, and 79–88 kW/(kg_LNG/s) for three-stage configurations. The corresponding net energy efficiencies are 6.6–7.5%, 10.1–11.2% and 10.8–12.0%, respectively, while the exergy efficiencies are 15.9–17.6%, 22.9–25.3%, and 24.3–26.8%, respectively. Two-stage systems achieve the lowest costs: a levelized cost of electricity (LCOE) of 80–105 €/MWh and a specific investment cost (SIC) of 6000–8300 €/kW. For most of the evaluated working fluids, the power gain from a third stage does not justify the increase in equipment costs. Among the evaluated working fluids, R32, R41 and R161 achieve the best economic performance, while carbonyl sulfide (COS), R32 and R161 achieve the best thermodynamic performance. The highest net power, 12.5 MW, is achieved with COS, whereas the lowest LCOE (80 €/MWh) and SIC (6000 €/kW) are obtained with R32, all for an LNG regasification capacity of 700,000 Sm³/h. Full article

Seawater zinc–air batteries (SZABs) stand out as promising candidates for marine and offshore energy supply. However, their practical implementation is greatly restricted by tardy oxygen reduction reaction (ORR) and oxygen evolution reaction (OER) kinetics at the air cathode, severe chloride ion-induced catalyst corrosion, and structural deterioration of traditional binder-containing electrodes in seawater media. Herein, we design and fabricate a binder-free integrated electrode consisting of carbon-supported iron phthalocyanine- modified star-like cobalt sulfide arrays directly grown on nickel foam. The optimal catalyst (0.3FePc-C/CoS) integrates the respective advantages of Fe single atoms and cobalt sulfide, exhibiting excellent ORR and OER activity, delivering a prominent half-wave potential of 0.89 V versus RHE, and exhibiting a low OER overpotential of 160 mV at 50 mA cm⁻² and robust stability in seawater. As a self-supported air cathode, the 0.3FePc-C/CoS-based battery attains a favorable open-circuit voltage reaching 1.48 V, prominent peak power density (126.4 mW cm⁻²), small charge–discharge potential polarization (0.52 V), excellent energy efficiency (68.8%) and extraordinary long-term cycling durability (>360 h). This work not only discloses a feasible synergistic modulation strategy for constructing high-performance bifunctional electrocatalysts but also provides a valuable reference for developing corrosion-resistant integrated air electrodes toward practical marine energy storage applications. Full article

This paper highlights the eco-efficiency of a sustainable digital solution to support decision-making in resolving the problem of sudden production drops and associated energy waste in industrial power plants, especially those operating with a steam turbomachine. The solution involves a multi-interface digital dashboard that generates insightful visual reports and gives proactive alerting to the decision-makers about potential underperformances to ensure resource optimization. For the studied use case, it involves the development of three interfaces of the dashboard, so as to perform the sustainable monitoring of a thermoelectric power plant based on the Rankine–Hirn cycle as follows: the first interface is about real-time monitoring of thirty-two key physical parameters equipped with a notification system. The second interface displays the historical trends of all the plant variables, in order to help in detecting incipient abnormal deviations before they impact environmental efficiency. Lastly, the third platform covers a predictive model using the XGBoost algorithmic method to forecast the future behavior of the electrical power as the target variable of the power plant. The XGBoost method was selected after a comparative assessment which also included the algorithms of Random Forest Regressor (RFR) and Gated Recurrent Unit (GRU). As a final step, this solution was later tested in a simulation environment built under the “Node-Red” platform, through an industrial decision scenario. The concrete findings validate the framework’s sustainability metrics, demonstrating the ability of the solution to help in preserving, for each production cycle of two years, up to 7.6 GWh of electrical energy that would otherwise be wasted, which translates into a potential cost-saving exceeding 633,247.9 USD, as well as an ecological impact by preventing the emission of 4628 tons of CO₂. Full article

Decarbonizing industrial energy consumption is critical for global sustainability. This study evaluates renewable energy alternatives to replace fossil-fuel power generation at an oil and gas facility in Khurais, KSA. A comparative thermodynamic and economic assessment was performed between a photovoltaic (PV) array and a parabolic trough collector (PTC) integrated with a Brayton cycle (BC) and a bottoming organic Rankine cycle (RC). The PTC-BC-RC model includes multi-generation capabilities for electricity, process hot water, and hydrogen via a PEM electrolyzer. The baseline PTC-BC-RC system generates up to 118.1 MW with a maximum thermal efficiency of 36.57%. The PEM electrolyzer utilizes 2% of the generated power to produce hydrogen at 0.0152 kg/s. Economically, the recuperated CSP system offsets its higher initial capital costs through diverse revenue streams (power, heat, and hydrogen), achieving a payback period of 5.13 years, significantly outperforming the PV system’s 6.80 years. Both configurations mitigate annual emissions by 747,000 tons of CO₂, 103.4 tons of NO_x, and 3.72 tons of SO₂. Despite regional limitations such as dust and water scarcity, the multi-generation PTC-BC-RC system proves economically and thermodynamically superior to the standalone PV system, offering a highly effective decarbonization strategy for industrial facilities in arid, high-irradiance zones. Full article

The development of high-performance cathode materials represents a crucial strategy for enhancing the overall electrochemical performance of aqueous alkaline zinc batteries. The rational design of electrode microstructure and chemical composition can synergistically boost the electrochemical reaction activity, ion/electron transport kinetics, and structural stability. In this work, a composite cathode material, FLG@Ni_xS₆/Co₄S₃/Ni-Co(OH)₂, was successfully synthesized via an electrochemical codeposition method. The engineered architecture offers abundant electrochemically active sites, well-defined ion diffusion pathways, and continuous electron conduction networks. Moreover, the strong interaction among the constituent phases effectively regulates and accelerates the redox reaction kinetics. When integrated into an aqueous alkaline zinc battery, the device attains a high specific capacity of 385 mAh g⁻¹ at 2 A g⁻¹, excellent rate capability (287 mAh g⁻¹ at 80 A g⁻¹), a gravimetric energy density of 590 Wh kg⁻¹, a power density of 128.57 kW kg⁻¹, and remarkable cycling stability, with 100% capacity retention maintained after 20,000 cycles. Overall, this study proposes a scalable and rational composite strategy for designing high-performance electrode materials for next-generation electrochemical energy storage systems. Full article

Hybridizing concentrating solar power (CSP) with photovoltaics (PV) offers a pathway to combine low-cost daytime generation with dispatchable nighttime supply. This study compares two CSP–PV hybridization concepts for Midelt, Morocco, under a common tender-style design framework: (i) a co-located configuration in which PV and CSP interact at the grid level and (ii) an EH-integrated configuration in which an electric heater (EH) uses PV electricity to heat molten salt in a topping cycle. The main contribution of this study lies in the two-stage optimization workflow, in which leading candidates are selectively re-simulated at higher temporal resolution. This workflow is applied to a common design framework that compares EH-integrated and co-located concepts while considering multiple PV technologies and a broad set of interdependent sizing variables. A surrogate-assisted genetic algorithm evaluates more than 200,000 candidate designs across PV technology, inverter size, TES capacity, EH capacity, and battery energy storage system (BESS) size. The optimization minimizes the levelized cost of energy (LCOE) subject to a $200 {\mathrm{MW}}_{\mathrm{el}}$ export limit, a CAPEX ceiling, and a nighttime-delivery constraint of ${\mathrm{CF}}_{\mathrm{night}}\ge 39\%$. Candidate designs are screened at 600 s and selectively re-simulated at 120 s, showing that temporal refinement affects not only KPI values but also candidate feasibility, final ranking, and preferred component sizing. The lowest-LCOE solution is the EH-integrated bifacial configuration, achieving 64.5% overall capacity factor, ${\mathrm{CF}}_{\mathrm{night}}=39.1\%$, less than 0.1% curtailment, a specific CAPEX of $4698/kW, and an LCOE of 7.29 ¢/kWh. Pareto-front and parameter-trend analyses further show that stricter nighttime-delivery targets shift the dominant sizing levers and define a neighborhood of near-optimal solutions rather than a single fixed design. Full article

Replacing artificial dyes with natural pigments in foods, especially carotenoids, has proven to be technologically feasible. This study developed a high-performance pitanga carotenoid extraction process using ionic liquids (ILs) and a factorial design to identify a potential substitute for artificial azo dyes, specifically Allura Red AC and Sunset Yellow FCF. 1-Hexyl-3-methyl-imidazolium chloride [C6mim]Cl was the most efficient IL. The optimized process conditions included a solid–liquid ratio R(S/L) of 1:10 m/m, an IL to ethanol co-solvent ratio R(IL/E) of 1:1 m/m, ultrasound power of 350 W, and six extraction cycles of 7 min each. These conditions yielded a total carotenoid content of 100.40 ± 3.71 μg/g (dry matter), demonstrating effective pigment recovery and a concentration suitable for practical use as a natural colorant alternative to synthetic azo dyes. The reuse of ILs and carotenoid purification were achieved through solid-phase extraction (SPE) using XAD-7HXP adsorbent, resulting in recovery rates of 89.2–76.2% for [C6mim]Cl and 108.9–23.2% for carotenoids. The major carotenoids identified were all-trans-β-cryptoxanthin, all-trans-rubixanthin, and all-trans-lycopene, whose combined presence contributed to a yellowish-orange hue similar to that of Sunset Yellow FCF, as confirmed by CIELAB parameters. Additionally, the [C6mim]Cl carotenoid extract exhibited high antioxidant activity, with an antioxidant capacity of 23.54 µmol of α-tocopherol equivalent. Full article

To evaluate the techno-economic performance of supercritical carbon dioxide (sCO2) power cycles in particle-based solar tower systems, thermodynamic and techno-economic models were established for four configurations: RC-ORC, RC, RE-ORC, and RE. A one-dimensional design method was used for key printed circuit heat exchangers, and multiple cost correlations with a trimmed-mean treatment were adopted to reduce the influence of extreme cost estimates. The results show that the primary heat exchanger (PHX) dominates system investment, accounting for more than 50% of total cost in all configurations. After screening 48 pure ORC working fluids, Cyclopropane and Trans-butene were identified as the economically preferable fluids for RC-ORC and RE-ORC, respectively. ORC working-fluid selection should therefore consider not only net power output, but also the effect of heat transfer and flow characteristics on intermediate heat exchanger cost. Scale analysis shows that the specific investment cost decreases rapidly over 50–300 MW, while the reduction becomes much smaller above 300 MW. At large scales, RC-ORC and RE-ORC gradually approach 1756.64 $/kW. These results highlight the importance of PHX cost reduction, heat-exchanger-oriented ORC fluid selection, and appropriate system scaling. Full article