{"title":"Innovative catalytic approaches for optimizing biodiesel production: A review of homogeneous, heterogeneous, enzymatic, and nanostructured catalysts","authors":"Suraj Bhan, Saket Kumar, Raghvendra Gautam, Prem Shankar Yadav, Girish Dutt Gautam, Sumit Mahajan","doi":"10.1002/ep.70052","DOIUrl":"10.1002/ep.70052","url":null,"abstract":"<p>This review examines the advancements in catalysts for biodiesel production, highlighting the benefits of innovative approaches such as homogeneous and heterogeneous catalysts, enzyme catalysis, and nanoparticles. It uniquely synthesizes insights into catalytic methods, evaluating their effectiveness and challenges, particularly in the context of high free fatty acid feedstocks. Alkaline catalysts, while efficient, face limitations due to saponification; however, recent developments in catalyst doping with metal oxides have significantly improved reactivity and mitigated side reactions. Homogeneous acid catalysts are effective for high FFA feedstocks but present challenges such as corrosiveness and high alcohol consumption. In contrast, heterogeneous catalysts, including solid materials like zeolites and metal oxides, offer enhanced separation, stability, and reusability. This review also highlights the role of enzyme catalysts, particularly lipases, emphasizing immobilization techniques and enzyme engineering for improved stability and reusability. A distinctive aspect of this work is its in-depth exploration of nanocatalysts, such as nanoparticles and Metal–Organic Frameworks, which enhance catalytic efficiency and stability due to their high surface area to volume properties. Additionally, the review critically assesses various preparation methods, including sol–gel and impregnation techniques, providing guidelines for future work. By identifying research gaps and future directions, this study contributes to the advancement of sustainable biodiesel production technologies.</p>","PeriodicalId":11701,"journal":{"name":"Environmental Progress & Sustainable Energy","volume":"44 5","pages":""},"PeriodicalIF":2.3,"publicationDate":"2025-07-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145102375","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Mohamed Rabia, Maha Abdallah Alnuwaiser, Salhah D. Al-Qahtani, Asmaa M. Elsayed
{"title":"Highly porous nanofiber of bismuth sulfide/poly-o-aminobenzenethiol-bismuth tungstate composite seeded on poly-1H pyrrole: Photocathode for green hydrogen generation without external sacrificing agent","authors":"Mohamed Rabia, Maha Abdallah Alnuwaiser, Salhah D. Al-Qahtani, Asmaa M. Elsayed","doi":"10.1002/ep.70051","DOIUrl":"10.1002/ep.70051","url":null,"abstract":"<p>A novel and highly porous nanofiber composite, Bi<sub>2</sub>S<sub>3</sub>–poly(O-aminobenzenethiol)/Bi<sub>2</sub>WO<sub>6</sub> (Bi<sub>2</sub>S<sub>3</sub>–POABT/Bi<sub>2</sub>WO<sub>6</sub> NF), was successfully synthesized via in-situ polymerization of O-aminobenzenethiol in the presence of Bi<sub>2</sub>WO<sub>6</sub>. The resulting nanofibers, with an average diameter of approximately 40 nm, provide abundant active sites for efficient photon absorption and hot electron generation. To fabricate an efficient photocathode, the Bi<sub>2</sub>S<sub>3</sub>–POABT/Bi<sub>2</sub>WO<sub>6</sub> NF composite was integrated onto poly(1H-pyrrole) (P1HP), forming a hybrid Bi<sub>2</sub>S<sub>3</sub>–POABT/Bi<sub>2</sub>WO<sub>6</sub> NF/P1HP photocathode. This photocathode demonstrated excellent photoelectrochemical performance for hydrogen production from both natural Red Sea water and laboratory-prepared artificial seawater. The measured photocurrent densities (<i>J</i><sub>ph</sub>) were −0.70 and −0.66 mA/cm<sup>2</sup> for natural and artificial seawater, respectively. Notably, the system produced 0.24 mmol/h of hydrogen over a 10 cm<sup>2</sup> photocathode area using natural seawater under illumination. Further analysis revealed that the photocathode exhibited strong photoresponse sensitivity to incident photon energy, with peak <i>J</i><sub>ph</sub> values of −0.67 and −0.61 mA/cm<sup>2</sup> at photon energies of 3.6 and 2.8 eV, respectively. These results highlight the promising potential of the Bi<sub>2</sub>S<sub>3</sub>–POABT/Bi<sub>2</sub>WO<sub>6</sub>/P1HP photocathode for sustainable hydrogen production. Its high efficiency, simple synthesis method, and compatibility with real seawater make it a viable candidate for practical solar-driven water-splitting applications.</p>","PeriodicalId":11701,"journal":{"name":"Environmental Progress & Sustainable Energy","volume":"44 5","pages":""},"PeriodicalIF":2.3,"publicationDate":"2025-07-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145102378","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Comparative evaluation of suspended and chitosan-encapsulated WRF consortium for decolorization of anthraquinone dye mixture","authors":"Pragnya Paramita Sahoo, Preeti Pallavi, Adyasha Anapurba Sahoo, Sudip Kumar Sen, Sangeeta Raut","doi":"10.1002/ep.70032","DOIUrl":"10.1002/ep.70032","url":null,"abstract":"<p>Mycoremediation is utilized for the breakdown of a mixture of anthraquinone dyes (MAQD). Due to co-metabolism, the White Rot Fungal Consortium (WRFC) is preferable to pure isolates. The suspended and chitosan-encapsulated WRFC5 (<i>Trametes cubensis</i> WF2, <i>Polyporus umbellatus</i> VS12, <i>Pleurotus pulmonarius</i> MTCC 1805 and <i>Leiotrametes flavida</i> MTCC 12927) were able to decolorize MAQD: Acid blue 129, Alizarin cyanin green, and Remazol brilliant blue R (200 ppm) by 44.53% and 97.35% respectively in 8 h with optimized inoculum size (6%), pH (7), temperature (30°C), glucose (1.25%), potassium nitrate (0.06%) and shaking speed (80 rpm). The reusability of immobilized WRFC5 in chitosan beads was possible up to 20 cycles, yielding a decolorization percentage of 78.85% for the 20th cycle in 8 h. TDS, BOD, and COD of MAQD were reduced by 92.94%, 70%, and 81.25% respectively using suspended WRFC5 and 97.57%, 98.75%, and 99.2% respectively using immobilized WRFC5 in 8 h. Suspended WRFC5 could also reduce color, chloride, nitrate, and lead by 44.53%, 42.66%, 94.33%, and 57.14% respectively, whereas immobilized WRFC5 could reduce by 97.35%, 84%, 99.99%, and 77.85% respectively in 8 h. MnP activity might be the reason for efficient decolorization and degradation by suspended and immobilized WRFC5. The highest MnP activity by suspended and immobilized WRFC5 was found to be 2089.93 and 61.89 U/mL respectively. The above study concluded that the developed chitosan-encapsulated WRFC5 could possibly be used as an excellent natural biomaterial for the simultaneous elimination of color, chloride, nitrate, and lead from MAQD-containing wastewater in a very short span of time and reused for around 20 cycles.</p>","PeriodicalId":11701,"journal":{"name":"Environmental Progress & Sustainable Energy","volume":"44 5","pages":""},"PeriodicalIF":2.3,"publicationDate":"2025-07-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145102249","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Environmental impacts of F-gases and trifluoroacetic acid: Potential threats to aquatic ecosystems and management strategies","authors":"Ahmet Elbir","doi":"10.1002/ep.70040","DOIUrl":"10.1002/ep.70040","url":null,"abstract":"<p>This study examines the environmental impacts of trifluoroacetic acid (TFA), a persistent and toxic compound formed as a degradation product of fluorinated gases (F-gases) commonly used in refrigeration and air conditioning systems. TFA is highly mobile, resistant to biodegradation, and accumulates in aquatic ecosystems, posing significant risks to biodiversity and ecosystem stability. Using environmental modeling, this research simulates TFA accumulation patterns and evaluates its ecotoxicological thresholds on aquatic organisms. The findings reveal that current regulatory frameworks underestimate the long-term ecological risks associated with TFA, including its bioaccumulation potential and toxicity to sensitive aquatic species. The study highlights the urgent need for greener refrigerant technologies, stricter environmental regulations, and globally coordinated monitoring strategies to mitigate TFA's environmental threats. Recommendations include transitioning to natural refrigerants such as CO<sub>2</sub>, ammonia, and hydrocarbons, developing next-generation cooling systems, and establishing maximum permissible concentration limits for TFA in water quality standards. Enhanced monitoring programs are necessary to track TFA accumulation in aquatic ecosystems and assess its long-term effects on biodiversity and public health. This research contributes to closing critical knowledge gaps regarding TFA's persistence and impacts, emphasizing the need for international collaboration and proactive measures to safeguard aquatic ecosystems and ensure sustainable environmental management.</p>","PeriodicalId":11701,"journal":{"name":"Environmental Progress & Sustainable Energy","volume":"44 5","pages":""},"PeriodicalIF":2.3,"publicationDate":"2025-07-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145102162","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Hybrid Photovoltaics cell with triboelectric nanogenerator: Overcoming energy availability limits and reducing optical scattering losses","authors":"Ramsundar Sivasubramanian, Chockalingam Aravind Vaithilingam, Suriati Paiman, Ashish Sharma, Indragandhi V","doi":"10.1002/ep.70046","DOIUrl":"10.1002/ep.70046","url":null,"abstract":"<p>Solar photovoltaics has long been a major research area in renewable and sustainable energy, with a large percentage of these efforts directed towards resolving PV limitations, the most critical of which is energy availability. The amount of solar PV power output is related to the amount of irradiation incident on it; hence, times of no or low irradiation levels result in zero or reduced power generation. The design and analysis of the optical performance of a contact-separation triboelectric nanogenerator integrated hybrid PV cell that can scavenge energy from rain without interfering with the device's normal operation is presented in this work. The hybrid cell's redesigned materials and structure enable it to minimize optical scattering losses recorded at the top glass layer of conventional PV devices by up to 50% while enhancing transmittivity from 90% to 95% across the visible wavelength range of 400–800 nm.</p>","PeriodicalId":11701,"journal":{"name":"Environmental Progress & Sustainable Energy","volume":"44 5","pages":""},"PeriodicalIF":2.3,"publicationDate":"2025-07-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145102187","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Investigation of an integrated clean energy system using heat recovery from fuel cell and LNG expansion waste heat combined with solar energy","authors":"Shoaib Khanmohammadi, Sajjad Khanjani, Hooman Abdi Chaghakaboodi","doi":"10.1002/ep.70029","DOIUrl":"10.1002/ep.70029","url":null,"abstract":"<p>This study examines the impact of integrating proton exchange membrane fuel cell (PEMFC) and reverse osmosis (RO) desalination systems into a solar liquid natural gas (SLNG) system. To this end, two configurations are analyzed: the basic SLNG system and the enhanced SLNG-PEMFC/RO system, incorporating PEMFC and RO technologies. Energy, exergy, and exergo-economic assessments are conducted for both setups. The findings reveal that integrating PEMFC and RO into the SLNG system boosts net output power by 26.22%, energy efficiency by 39.28%, and production revenue by 201%. However, the exergy efficiency, LCOE, and payback period of the SLNG-PEMFC/RO system are 31.84%, 82%, and 205.5% lower, respectively, compared to the base SLNG system. Additionally, increasing PEMFC temperature enhances net output power, energy efficiency, and exergy efficiency by 26.5%, 4.64%, and 11.03%, respectively. On the other hand, higher PEMFC temperatures result in increases of 10.56% in LCOE and 21.5% in production revenue. Notably, PEMFC pressure has the least influence on the performance of the SLNG-PEMFC/RO system.</p>","PeriodicalId":11701,"journal":{"name":"Environmental Progress & Sustainable Energy","volume":"44 5","pages":""},"PeriodicalIF":2.3,"publicationDate":"2025-07-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145102138","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Optimum fin configurations for solar air heater enhancement: Theoretical approach","authors":"Moataz M. Abdel-Aziz, Abd Elnaby Kabeel","doi":"10.1002/ep.70056","DOIUrl":"10.1002/ep.70056","url":null,"abstract":"<p>Solar Air Heaters (SAHs) face performance limitations due to inefficient heat transfer mechanisms. To address this, the current numerical study utilizes Computational Fluid Dynamics (CFD) to systematically optimize fin configurations. By first focusing on optimizing the fin tilt angle and subsequently refining the fin height, this methodology addresses key parameters influencing heat transfer efficiency and overall system performance. The systematic study of cooling effectiveness by varying the flow rate on the SAH, ranging from 0.0025 to 0.02 kg/s, is aimed at determining the optimal tilt angle and fin height to boost the thermal efficiency of the SAH within the radiation range of 400–1000 W/m<sup>2</sup>. Remarkably, the investigation reveals that for a zero-tilt angle and a 0.01 kg/s mass flow rate, there is a notable enhancement in average thermal efficiency, reaching 42.18%. Additionally, the findings highlight that for a fin height of 15 mm and the same flow rate of 0.01 kg/s, the average thermal efficiency significantly improves, reaching 49.67%. These results signify the critical role of both tilt angle and fin height in optimizing the SAH thermal performance. The identified optimal configurations, such as the zero-tilt angle with an air flow rate of 0.01 kg/s and a fin height of 15 mm, underscore the potential for substantial improvements in SAH efficiency. These results offer insightful information for creating and enhancing SAHs, offering pathways to enhance their energy conversion capabilities and overall performance.</p>","PeriodicalId":11701,"journal":{"name":"Environmental Progress & Sustainable Energy","volume":"44 5","pages":""},"PeriodicalIF":2.3,"publicationDate":"2025-07-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145101438","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Antonio Carlos Pacagnella Junior, Gustavo Hermínio Salati Marcondes de Moraes, Adauto Lucas da Silva, Fernando Ferrari Putti, Wagner Wilson Bortoletto
{"title":"Clean development mechanisms in Latin America: Efficiency analysis of energy-generating projects","authors":"Antonio Carlos Pacagnella Junior, Gustavo Hermínio Salati Marcondes de Moraes, Adauto Lucas da Silva, Fernando Ferrari Putti, Wagner Wilson Bortoletto","doi":"10.1002/ep.70023","DOIUrl":"10.1002/ep.70023","url":null,"abstract":"<p>This research addresses two key questions related to Clean Development Mechanism (CDM) This research aimed to address two research questions related to CDM projects focused on energy generation in Latin America. The first question aimed to identify the most efficient projects carried out in this region, while the second question sought to identify their characteristics. These questions were proposed based on a clear gap identified in the scientific literature, particularly regarding these ventures developed in the region, which may be of interest to researchers, investors, and project managers alike. To answer these questions, a quantitative analysis was conducted using the database on CDM projects provided by the United Nations Framework Convention on Climate Change, employing two techniques. The first technique used was Data Envelopment Analysis, which generated an efficiency ranking for these projects. In this study, efficiency is considered as the results achieved by the project in terms of energy generation capacity and carbon emission reduction, relative to the resources invested in it. The second technique was the non-parametric Mann–Whitney test, which helped identify characteristics that exhibited significant differences in efficiency. Among the findings, three key characteristics were identified as relevant in explaining this difference: project scale, type, and country where they were developed. Large-scale projects—specifically those in the categories of Methane Avoidance, Landfill Gas, and Energy Efficiency Supply Side—as well as projects carried out in Mexico and Colombia, demonstrated significantly higher efficiency based on the model used in this research. Furthermore, Hydro and Biomass Energy projects were identified as having significantly lower efficiency compared to the others. The outcomes of this study hold significance in two aspects. Firstly, from an academic standpoint, it expands the understanding of project characteristics of these projects in Latin America by establishing a comparative analysis among them. Secondly, from a more practical perspective, the results can guide investors in defining a more suitable profile for energy-generating CDM projects, thereby reducing risks and increasing the likelihood of success. Moreover, these findings can lay the foundation for the formulation of public policies aimed at promoting projects with a more efficient profile. This is especially important given the waning interest in this crucial mechanism over the past decade, potentially spurring the execution of new projects and altering this reality.</p>","PeriodicalId":11701,"journal":{"name":"Environmental Progress & Sustainable Energy","volume":"44 5","pages":""},"PeriodicalIF":2.3,"publicationDate":"2025-07-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://aiche.onlinelibrary.wiley.com/doi/epdf/10.1002/ep.70023","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145102045","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Mohamed Rabia, Asmaa M. Elsayed, S. Fernández, Eman Aldosari
{"title":"Promising morphology of Poly-2-Mercaptoaniline/reduced graphene oxide nanosheets photocathode for green hydrogen generation from natural and artificial Red Sea water","authors":"Mohamed Rabia, Asmaa M. Elsayed, S. Fernández, Eman Aldosari","doi":"10.1002/ep.70048","DOIUrl":"10.1002/ep.70048","url":null,"abstract":"<p>A thin-film photocathode composed of Poly(2-mercaptoaniline)/Reduced Graphene Oxide Nanosheets (P2MA/rGO-NS) was synthesized through a two-step process involving the in situ chemical reduction of graphene oxide by the 2-mercaptoaniline monomer, followed by oxidative polymerization to form the conducting polymer matrix. The resulting hybrid structure exhibits a compact and homogeneous morphology, where P2MA particles (~140 nm) are uniformly distributed within rGO sheets (~100 nm), facilitating efficient charge transport and interfacial contact. Optical analysis confirms broadband light absorption with an optical bandgap of ~2.4 eV, as suitable for visible-light-driven photoelectrochemical applications. The photocatalytic efficiency of the P2MA/rGO-NS photocathode was assessed for hydrogen evolution using both natural Red Sea water and an equivalent synthetic seawater as electrolytes in a standard three-electrode configuration. At −0.72 V, the photocurrent densities reached −0.7 and −0.5 mA/cm<sup>2</sup> for natural and artificial seawater, respectively, correlating with an average hydrogen evolution rate of 18 μA per 10 cm<sup>2</sup> per hour. The wavelength-dependent photoresponse under monochromatic illumination demonstrated peak photocurrent densities of −0.63 and −0.57 mA/cm<sup>2</sup> at 340 and 440 nm, respectively, with a gradual decline to −0.54 mA/cm<sup>2</sup> at 730 nm, indicating broad-spectrum responsiveness. The excellent photocatalytic performance, combined with stable operation under chopped illumination, low-cost fabrication, and scalability, positions the P2MA/rGO-NS photocathode as a strong candidate for sustainable hydrogen production from seawater in industrial-scale application.</p>","PeriodicalId":11701,"journal":{"name":"Environmental Progress & Sustainable Energy","volume":"44 5","pages":""},"PeriodicalIF":2.3,"publicationDate":"2025-07-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145101598","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Experimental investigation of heat transfer and fluid flow in solar air heaters using transverse wire rib roughness with variable gaps","authors":"Dilbag Singh Mondloe, Harish Kumar Ghritlahre, Gajendra Kumar Agrawal","doi":"10.1002/ep.70049","DOIUrl":"10.1002/ep.70049","url":null,"abstract":"<p>Solar air heaters are widely used in low-temperature applications such as drying, heating, etc. The growth of the laminar sub-layer under the absorber plate in conjunction with flowing air leads to lower convective heat transfer and, thereby, low performance. In this present work, the conventional solar air heater is reconfigured using transverse wire ribs with variable gaps to break the laminar sub-layer. The experiment was performed under actual outdoor weather conditions in Jagdalpur, India. The important design and control variables used are relative roughness height (<i>e</i>/<i>D</i>) of 0.043, relative roughness pitch (<i>p</i>/<i>e</i>) of 10, gap width (<i>g</i>) of 4 mm, rib roughness diameter (<i>e</i>) of 2 mm, the number of gaps (Ng) varying from 1 to 4 (in 4 steps) and Reynolds number in the range of 2000–16,000 (in 8 steps). The experimental result indicates that the maximum Nusselt number and friction factor are achieved for Ng = 2 compared to all the gaps. Ng = 2 configuration outperforms both continuous rib and smooth duct configurations. The findings show that the maximum augmentation in heat transfer and fluid friction compared to smooth ducts is 3.04 and 3.03, respectively. The optimal parameters identified as <i>p</i>/<i>e</i> = 10, <i>e</i>/<i>D</i> = 0.043, <i>e</i> = 2, <i>g</i> = 4, and Ng = 2 resulted in the highest enhancement in heat transfer across all cases studied. The heat transfer found in the present study outperforms that of prior investigations in the field of solar air heaters, which utilized similar rib configurations but did not incorporate variable gaps.</p>","PeriodicalId":11701,"journal":{"name":"Environmental Progress & Sustainable Energy","volume":"44 5","pages":""},"PeriodicalIF":2.3,"publicationDate":"2025-07-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145101544","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}