https://hfe.irost.ir/ Hydrogen, Fuel Cell & Energy Storage en daily 1 Sun, 08 Mar 2026 00:00:00 +0330 Sun, 08 Mar 2026 00:00:00 +0330 https://hfe.irost.ir/article_1683.html Recent research has increasingly focused on high-efficiency systems powered by renewable energy sources to address global warming, prevent ozone layer depletion, and ensure stable and accessible energy supplies. Among these sources, geothermal energy stands out for its ability to power thermodynamic systems capable of generating multiple outputs. The efficiency of a stand-alone flash-binary geothermal power plant decreases due to input energy losses. To enhance overall performance and reduce costs, structural modifications and waste heat recovery techniques can be implemented. This study proposes and investigates an innovative waste heat recovery system integrated into a dual-flash binary geothermal power plant. The combined system incorporates a Rankine cycle and a proton exchange membrane electrolyzer. The system focuses on two major processes: converting waste heat into power and producing hydrogen from the generated power. Its feasibility is evaluated from thermodynamic and economic perspectives. The system analysis was performed using EES (Engineering Equation Solver) software. Results indicate energy and exergy efficiencies of 23.97% and 35.35%, respectively. Moreover, the total power generated by the system, incorporating two turbines and two thermoelectric generators (TEGs), is 5981 kW. The system also produces hydrogen at a rate of 0.0295 kg/s. Moreover, based on the exergy destruction analysis, TEG 2 and the compressor exhibit the highest rates of exergy destruction. https://hfe.irost.ir/article_1696.html Biohydrogen is a feasible and environmentally sustainable fuel for the world's growing energy demand. As an alternative renewable energy source, hydrogen contains 2.75 times more energy per gram than any other known source. Biohydrogen is produced from various microorganisms and renewable materials through anaerobic dark fermentation and phototrophic bacteria, operating in batch, semi-continuous, and continuous modes. Anaerobic dark fermentation has a higher production rate and yield compared to photo-fermentation. In this review, the dark fermentation of hydrogen is discussed concerning key influential parameters and environmental factors such as temperature, pH, hydraulic retention time, mass transfer coefficient, and recycle ratio. A low initial pH affects metabolic pathways, prolongs the lag phase, and enhances Fe-hydrogenase activity. Mesophilic, thermophilic and ultrathermophilic strains could tolerate maximum operating temperature of 40, 65 or 108°C, respectively. A varity of fermenters are continuously used for biohydrogen production, with a few discussed here. Tower-type fermenters are more feasible than CSTRs as they provide a higher hydraulic retention time for continuous biohydrogen production. Fluidized beds are used for both short- and long-term hydraulic retention time operations. Hydraulic retention time (HRT) typically depends on the bioreactor type, geometry, and feed composition, particularly the carbon source. When wastewater is used, HRT generally ranges from 8 to 14 hours. However, the process requires more detailed data to fully understand and overcome thermodynamic limitations. These limitations could be addressed through genetic modification or metabolic pathway alterations to enhance biohydrogen yield, making large-scale and commercial production more feasible. https://hfe.irost.ir/article_1697.html This article presents a novel three‑dimensional numerical investigation of turbulent water–air flow and displacement heat transfer in a shell‑and‑tube heat exchanger enhanced with paraffin phase‑change material (PCM) and aluminum oxide nanoparticles. Covering Reynolds numbers from 0 to 3 000, the governing equations are solved via the finite‑volume method.The study's findings indicate that employing phase-change material surrounding the tube and keeping a steady heat flux can both increase a shell and tube heat exchanger's penetration coefficient. The impact of this modification has been compared to that of a straight, circular tube, providing practical insights for heat exchanger design. The chosen fluid flow exhibits turbulence as it moves through the tube and collides with the thermal boundary layer, increasing the internal transfer coefficient of the fluid flow. The findings show an insignificant error of 8.71\% for the grid independence section. https://hfe.irost.ir/article_1680.html This study presents a novel fabrication method for metal/ceramic membranes, providing a cost-effective substitute for traditional, expensive Pd-based membranes. While nickel offers a promising replacement for Pd-based membranes, its effectiveness in H2 separation depends on whether it can function independently or must be incorporated into Pd-based alloys to enhance performance and reduce fabrication costs. To investigate this, a homogeneous and thin (2 µm) nickel composite membrane was fabricated with the organic-inorganic activation (OIA) process in the electroless plating (ELP) technique for the first time. At 25°C and a differential pressure of 400 kPa, the hydrogen flux of the membrane was measured at 3.26×10-2 molm-2 s-1, with a separation factor of 3 for H2/N2. The findings demonstrated that Knudsen diffusion was the prevailing mechanism for H2 transport across the membrane. https://hfe.irost.ir/article_1698.html Despite the abundance and high density of Mg metal as an anode, the limited development of Mg-air batteries is primarily due to the surface reactions of the Mg anode in water-based electrolytes. A reliable strategy to improve metal anode efficiency is to prevent anode surface reactions by designing and applying suitable protective coatings. In this study, a polyaniline (PANI) polymer coating was designed and synthesized to modify the surface of Mg anodes. The primary scope of this research is to examine the effect of coating on the Mg anode surface and its ability to control surface reactions, including corrosion. Electrochemical analyses confirm the optimal efficiency of the PANI coating in inhibiting the corrosion of the surfaces of Magnesium, as evidenced by comparisons between uncoated and PANI-coated samples. As a result, Mg with PANI coating has a smaller corrosion current and a larger corrosion potential (5.06×10-5 A/cm2, 1.01 V) than uncoated Mg (6.3×10-4 A/cm2, 1.49 V), respectively. Because of its chemical durability and good electrochemical behavior, PANI can overcome the limitations of using Mg anodes as a protective surface coating, improving the efficiency of Mg-air batteries and developing new technologies. https://hfe.irost.ir/article_1699.html This study presents an in-depth thermodynamic and economic evaluation of a hybrid geothermal energy system utilizing Kalina cycle technology for multipurpose power generation. The system is designed to produce electricity and heating while supplying cooling, hydrogen, and freshwater. The integrated system reaches a total energy efficiency of 47.6\% and an exergy efficiency of 44.2%. Raising the high pressure setting in the Kalina cycle to 4900 kPa reduces the exergy destruction cost rate to $1486.49/h, the total cost rate to $2464.12/h, and the capital investment rate to $922.12/h, compared to the base pressure of 4000 kPa where these rates were $1912.08/h for exergy destruction and \$3084.00/h for total cost and $1171.92/h for capital investment. The exergetic assessment shows Turbine 2 and the Compressor as the main contributors to system exergy destruction, with outputs of 2545.33 kW and 2353.09 kW, respectively. At a rate of 0.1524 kg/h the system establishes two operational capabilities: hydrogen production and a cooling output of 3498 kW. The research indicates that the combined multigeneration system enhances resource utilization ofgeothermal energy by maximizing energy efficiency and decreasing operational costs. https://hfe.irost.ir/article_1700.html This study examines a sustainable energy framework designed for hydrogen production. It includes various components like a geothermal energy module, a Claude cycle system for hydrogen liquefaction, and a modified organic Rankine cycle. A detailed investigation into its operational features is conducted across various aspects, with its energy conversion efficiency measured using key performance indicators. The assessment of operational effectiveness was based on factors such as energy yield, exergy utilization, and economic considerations. A sensitivity analysis assesses how changes in operation affect performance. A dual-objective genetic algorithm with the TOPSIS method enhances the hydrogen production infrastructure. The system achieves an energy conversion efficiency of 45% and exergy efficiency of 53%, producing 4.88 kg of hydrogen per hour and 1,425 kW of power, with operational costs of $37.16 per hour. The Levelized Cost of Energy is 19.8 cents per kWh, while the Levelized Cost of Hydrogen is 24.39 $/kg. The energy needed for hydrogen liquefaction is reduced through a two-stage thermal management strategy. https://hfe.irost.ir/article_1645.html The current paper provides a thermodynamic, and thermoeconomic analysis of a new multigenerational energy system consisting of the solar thermal energy source and the wind source. This consists of a Brayton cycle driven by a solar tower, a Steam Rankine Cycle (SRC) with feedwater heater and makeup condensate pump, an Organic Rankine Cycle with ejector refrigeration (ORC-ERC), a thermoelectric generator (TEG), a proton exchange membrane (PEM) electrolyzer and a reverse osmosis (RO) desalination plant so that electricity, hydrogen, freshwater, heating, cooling and domestic hot water are produced simultaneously. It has overall annual power output of 38.37 MW, thermal efficiency of 25.22\% and exergy efficiency of 50.7\%. The saltwater has a desalting rate of 0.008 kg/s and hydrogen at 19.37 kg/s. The greatest exergy losses can be found in the solar collector, compressors and the combustion chamber pointing out to the areas where improvements can be introduced. From Thermoeconomic point of view, gas turbine is deemed to be capital intensive and the solar collector and wind turbine are highly cost effective. Sensitivity studies show that raising the gas turbine inlet temperature and increment of the pressure ratio of the compressor will boost the performance considerably. All in all, the suggested pathway is not only a technically viable and financially beneficial model of clean, diversified energy production with affinities to locations that have plentiful resources of both solar and wind power. https://hfe.irost.ir/article_1487.html In this paper, a power, refrigeration, and hydrogen production cycle using geothermal energy in a binary flash cycle has been conducted from a thermodynamic perspective. The cycle involves a basic condensation refrigeration cycle combined with a binary flash cycle and PEM electrolyzer, with geothermal energy as the driving force. A thorough thermodynamic simulation was carried out using EES software, and a parametric study of the proposed cycle was performed to demonstrate its operability under various input parameters. The results show that TEG 2 and the compressor exhibit the highest exergy destruction rates based on the exergy destruction rate analysis. Moreover, increasing the temperature of the first flash tank results in higher power and hydrogen production rates. Furthermore, increasing the temperature of the second flash tank leads to decreased energy and exergy efficiencies, power, and hydrogen production rates. Also, an increase in the geothermal mass flow rate causes a decrease in the power and hydrogen production rates of the system. Finally, it is found that a higher temperature difference results in a decrease in the hydrogen production rate. https://hfe.irost.ir/article_1551.html Understanding and projecting lithium pricing fluctuations will become increasingly important as the world shifts toward cleaner energy sources and electric mobility. Accurate prediction of lithium prices using accessible and reliable methods is essential for sustainable lithium extraction practices. This study employs machine learning (ML) techniques to forecast the costs of future lithium production, with an emphasis on the relationship between the supply of lithium, the use of EVs, and the renewable energy. To find the most precise approach, five ML models are investigated: K-Nearest Neighbors (KNN), Support Vector Classifier (SVC), Linear Support Vector Regression (SVR), Linear Regression, and Multi-Layer Perceptron (MLP) Regression. KNN emerges as the top performer among them, exhibiting robust prediction capabilities, and it is used as the applied ML model in this work. Eight likely scenarios that could affect lithium prices in the upcoming years are examined. These scenarios include advances in lithium extraction technology, alterations to EV usage patterns, and rising demands for the production of renewable energy. Results reveal that the ML model forecasts a notable upward trend in lithium prices. After 2022 to 2029, as the production of EVs and renewable energies increases, lithium prices are projected to rise substantially from USD 20,973/ton to USD 37,745/ton. From 2029 to 2037, with growing demand for batteries, the price is predicted to rise from USD 37,745/ton to USD 40,747/ton. Despite potential short-term fluctuations due to external factors, the model indicates that the long-term trajectory remains upward in lithium prices by 2040. https://hfe.irost.ir/article_1583.html In recent years, the Solar Stirling Thermal Oscillator (SSTO) has emerged as one of the most effective systems for converting solar energy into mechanical and electrical energy, attracting significant interest from researchers. The main challenge in harnessing these oscillators is to ensure the establishment of stable oscillations in their nonlinear dynamics for consistent and reliable performance. The main contribution of this work is the introduction and application of bifurcation theory for the first time to analyze the nonlinear dynamic behavior of the SSTO and to precisely identify the critical points at which stable limit cycles emerge. In this study, by studying the effects of crucial parameters such as power piston mass, stiffness spring of the displacer piston, and the hot source temperature, the critical ranges related to the onset of stable oscillations in the SSTO have been determined. The outcomes demonstrate that bifurcation analysis provides a novel and powerful tool for assessing and optimizing the design of SSTOs, enabling reliable prediction and assurance of stable dynamic performance before practical implementation. This method offers an effective and new pathway for the reliable and cost-efficient design of SSTOs. https://hfe.irost.ir/article_1614.html A new geothermal multisource energy system is assessed in this research upon a comprehensive 4E framework of the Energy, Exergy, Economic, and Environmental aspects. The system integrates numerous technologies for energy conversion and use, which includes an Organic Rankine Cycle (ORC) coupled with a Thermoelectric Generator (TEG), a Single-Effect Absorption Chiller (SEAC), a Proton Exchange Membrane (PEM). A distinct benefit of the system is its use of a TEG instead of the usual condenser, allowing waste heat to be converted into extra electricity via the Seebeck effect, thus enhancing the efficiency of energy conversion without using extra power. The multigeneration system is designed to produce electricity, heating, cooling, hydrogen and freshwater which makes it perfect for regions endowed with geothermal resources and various energy demands. The simulation results demonstrating a comprehensive thermodynamic simulation indicate that the system has 66.42% energy efficiency and 77.12% exergy efficiency. Based upon exergoeconomic analysis, the capital and maintenance expenditure is mainly financed by the turbines and also the geothermal unit, with a scope for improvement on the heat exchangers and condensers. In general, activity environment index of the system 0.03206 corresponds to negligible ecological disturbance, and its exergy sustainability coefficient is 0.0711, which points out the possibility of further enhancement of sustainability. This geothermal setup is poised excellently as an efficient, sustainable and multipurpose energy solution as per results. https://hfe.irost.ir/article_1615.html A new biomass system that produces electricity, provides heat, makes hydrogen and offers freshwater is described and analyzed in this paper. The proposed setup combines a gas turbine, a supercritical CO₂ cycle, a Kalina cycle, a PEM electrolyzer and a multi-effect desalination (MED) unit. The purpose of this method is to allow energy recovery and minimize its environmental effects on the entire system. To assess how the system operates, detailed thermodynamic and exergoeconomic evaluations were completed for several operating scenarios. The results indicate that high efficiencies have been achieved, with hydrogen and freshwater consistently produced and with almost no irreversible losses during production. The specific unit cost of product (SUCP) was determined to be 17.67 $/GJ, showing that operation costs are low when compared to others. Biomass Energy has shown that raising turbine inlet temperature and controlling biomass moisture content permits the system to work more efficiently and recoup more energy. All in all, it turns out that biomass used in integrated systems provides an effective and environmentally friendly way to supply electricity and heat to many applications when a lot of biomass is available. https://hfe.irost.ir/article_1623.html Due to the irregular availability of natural gas, coal has been proposed as an alternative source for the production of synthesis gas in steel plants. This study simulated of a coal gasification unit aimed at producing synthesis gas. The model was initially validated against available reference data, confirming its accuracy. Using Tabas coal as feedstock, and the gasification process was simulated using an entrained-flow gasifier in Aspen Plus software. Sensitivity analysis was conducted on the type of coal, as well as on the water-to-coal and oxygen-to-coal ratios, to identify key factors affecting the process. Key results show that approximately 29 tons per hour of Tabas coal is required to produce 174.6 m³/h of syngas, sufficient for 110 tons per hour of sponge iron production. Process water consumption is around 0.3 times the coal input, with a cooling and quenching water-to-coal ratio of approximately 1.7, much of which is reused. Significantly, additional water is not required for the water-gas shift reaction due to syngas quenching within the gasifier. The study confirmed that both the type of coal used and the ratios of water and oxygen to coal are critical, with high-quality Tabas coal demanding lower amounts of oxygen and water for syngas production compared to lower-grade coals. This research serves as a valuable guide for improving the efficiency and productivity of coal gasification units in the steel industry. Overall, the findings indicate that using coal for synthesis gas production has great potential in meeting energy demands and enhancing steel industry productivity. https://hfe.irost.ir/article_1677.html The growing need of the flexible and low-carbon energy provision has propelled the adoption of multigeneration systems that utilize renewable heat concurrently with waste heat and cryogenic energy. This paper introduces a new solar-assisted natural-gas combined-cycle (NGCC)-based multigeneration design which combines a gas-turbine Brayton cycle, a steam Rankine cycle, a solar-powered organic Rankine cycle (ORC) to liquefied natural gas (LNG) cold-exergy recovery, an absorption refrigeration system and a proton-exchange-membrane (PEM) electrolyzer to co-produce electricity, hydrogen, heating and cooling. A thermodynamic model is developed and validated coupled with the energy, exergy, exergoeconomic, environmental as well as sensitivity analyses. The suggested design provides 186.3 MW of net electricity at an electrical efficiency rate of 51.3 % and exergy efficiency rate of 33.8 %. The system also generates hydrogen at a rate of 0.502 kg/s, provides cooling of 1.53MW, and recovers 27.3MW of valuable heating with LNG regasification. The combustion and high-temperature heat-recovery units comprise most of exergy destruction and, thus, the main focus of further performance enhancement; exergoeconomic outcomes also show that the mitigation of irreversibilities in the said units are the most promising in terms of cost reduction. On electricity-only basis, environmental assessment gives a particular CO2 emission of 0.352 kg/kWh or 0.349 kg/kWh when co-products are added on an electric-equivalent basis. The parametric analyses are a confirmation that the solar irradiation, turbine inlet temperature, compressor pressure ratio, and LNG regasification pressure are of great influence of the system performance. https://hfe.irost.ir/article_1679.html The organic Rankine cycle and an ejector refrigeration cycle (ORC-EJR) are combined in this work to create a unique multigeneration cycle that is investigated from a thermodynamic standpoint. The system can produce heat, cooling, power, and hydrogen. Geothermal energy is used in this suggested design as a sustainable energy source. It is cost-effective and energy waste-free to use a renewable energy source to produce many outputs. Furthermore, this system generates additional electricity by using a thermoelectric generator (TEG) unit in place of the condenser. After analysing, it is found that increasing the turbine inlet pressure leads to improvements in all evaluated parameters, such as energy and exergy efficiency, cooling load, COP, power output, and hydrogen production rate. Moreover, an elevation in turbine inlet pressure loads to diminished energy and exergy efficiencies, lowered power generation output, and reduced hydrogen production rates. Furthermore, an enhancement in the TEG’s figure of merit results in better energy and exergy efficiencies for the system, as well as increased power and hydrogen production rates. Finally, it is approved that the preheater exhibits the highest rate of exergy destruction rate among the systems examined. https://hfe.irost.ir/article_1714.html The gradual depletion of fossil fuel reserves has renewed interest in hydrogen (H₂) as a durable and sustainable energy carrier. However, its successful application on an industrial scale hinges on removing trace contaminants particularly carbon dioxide (CO₂) from mixed gas streams. In this study, the separation of CO₂ from CO₂/H₂ mixtures was investigated using the metal organic framework SIFSIX 3 Cu and Grand Canonical Monte Carlo (GCMC) simulations across a wide range of temperatures and pressures. Two gas compositions (molar ratios CO₂/H₂ of 0.90/0.10 and 0.79/0.21) were examined between 298 K and 370 K. In every case, CO₂ uptake was markedly higher than that of H₂, and the adsorption of both gases decreased with increasing temperature. The Langmuir isotherm model provided an excellent fit to the observed data, indicating monolayer adsorption behavior. The isosteric heats of adsorption were calculated to be about 54 kJ mol⁻¹ for CO₂ and roughly 2 kJ mol⁻¹ for H₂, reflecting the stronger electrostatic attraction between CO₂ molecules and the SiF₆²⁻ sites in the framework. Spatial density distribution analysis revealed that CO₂ molecules preferentially occupy regions near the SiF₆²⁻ units, whereas H₂ molecules are mainly located around pyrazine rings. Overall, these findings highlight the pronounced CO₂ selectivity of SIFSIX 3 Cu even at low concentrations and underline its potential for hydrogen purification in industrial gas separation processes. https://hfe.irost.ir/article_1739.html Minor temperature variations are often considered negligible in the mechanical design and operation of confined granular systems. However, due to the discrete nature of particle interactions, even small thermally induced expansions can generate significant contact stresses within granular assemblies. This study focuses on thermal-driven stress in mono-disperse isotropic granular materials using discrete element method based on the Hertz-Mindlin no-slip contact model. Thermal loading is introduced through uniform radial expansion of particles, allowing direct assessment of contact force and pressure evolution under controlled temperature changes. The model is validated against COMSOL Multiphysics, ensuring accurate quantification of contact-level stresses. Furthermore, a parametric study is conducted to evaluate influence of particle size, enclosure slenderness ratio, and solid fraction on the resulting contact stresses. The results show that even minor temperature increment can induce contact pressures of considerable magnitude, which may locally approach or exceed yield strength of the particle material. These findings indicate that such thermal stresses are not merely secondary effects but critical factors in the mechanical performance of granular assemblies. In addition, while particle size exhibits a negligible effect on contact pressure due to compensating changes in contact force and contact area, both the slenderness ratio and solid fraction show an approximately linear correlation with the induced stresses, indicating a strong dependance on geometric confinement and packing density. To extend the predictive capability of the numerical model and reduce computational cost, an artificial neural network is trained using the DEM results, demonstrating high accuracy in predicting particle-particle and particle-wall contact pressures.