This article has been retracted: please see Elsevier Policy on Article Withdrawal (https://www.elsevier.com/about/policies/article-withdrawal). This article has been retracted at the request of Elsevier's Research Integrity & Publishing Ethics team and an independent ethics advisor. A journal-wide investigation identified violations of the journal's policies on authorship and conflict of interest related to the submission and review of this paper. Review of this submission was handled by the then Editor-in-Chief (Ashok Pandey) despite an extensive record of collaboration, including co-publication, with four of the paper co-authors (Binod Parameswaran, Raveendran Sindhu, Mukesh Kumar Awasthi, Mohammad J. Taherzadeh). In addition, authorship changes were made during the revision of this paper; the authors Deepanraj Balakrishnan and M. Mofijur were added to the revised paper without validation or authorisation. There was a significant increase of citations of papers authored by the Editor-in-Chief between the original submission and the revised version. In summary, 3 papers by Pandey were cited in the original version of the paper. This increased to 10 papers in the revised version. Acceptance of the article was partly based upon the positive advice of a reviewer who was closely linked to one of the authors (Awasthi). This compromised the editorial process and breached the journal's policies. This investigation was carried out by Elsevier's Research Integrity & Publishing Ethics team, independent of the journal editorial board. The findings and recommendations have been confirmed by an independent ethics advisor. The authors disagree with the retraction and dispute the grounds for it. © 2025 Elsevier Ltd

Natural gas is extracted from the subsoil which is not a renewable source, however, the dominance of this product in the international market is significantly higher in future. It reflects the global view of renewable sources (biogas) and hinders the sustainable development of bioenergy. It describes the major issues and trends in the development of biogas industry, paying special attention to current biomass upgrading technologies, methane activation for fuel production and model compounds investigation. The conducted research gives reason to believe that the valorization of organic waste generated worldwide during the production of biomethane that can potentially satisfy. No more than one fifth of global demands for natural gas due to technical difficulties and economic constraints associated with the purification of biogas. The existing production potential of biogas production is focused on obtaining biomethane and high growth rates of demand for biohydrogen. A pressing need arises the possibilities for further development of biogas industry lie in optimizing the biomethanation processes, which allows to reduce the costs of biogas modernization system and decreasing the negative effect on climate changes by replacing petrochemical derived fuels with biofuels in various sectors of economy. © 2024 Elsevier B.V.

The growing demand for energy and the necessity to enhance the efficiency of heat exchangers have triggered numerous studies aimed at improving convective heat transfer rates while simultaneously reducing the size and investment costs of industrial devices. In this comprehensive review, a thorough analysis of recent literature has been undertaken to explore the latest advancements in tubular, plate, and extended surface heat exchangers, considering factors such as geometry, materials, and heat transfer fluids. The review comprehensively covers passive, and combined approaches to convective heat transfer (CHT) enhancement in these heat exchangers. Consideration is afforded to research studies exploring passive techniques in double pipe heat exchangers (DPHEXs), plate heat exchangers, and extended surface heat exchangers. The review extensively explores surface modifications such as corrugated surfaces, twisted tapes, and rough surfaces in heat exchangers. It provides detailed insights into the impact of these modifications on CHT rates and overall heat exchanger performance. The review also encompasses an examination of different chevron angles and the use of various refrigerants in plate heat exchangers. It offers a comprehensive overview of the effect of these factors on the performance of plate heat exchangers. Furthermore, the review examines an analysis of various types of fins utilized in different heat exchangers, exploring their effectiveness in conjunction with different heat transfer fluids. This examination provides insights into the interactions between fin configurations and heat transfer fluids, contributing to a comprehensive understanding of their impact on heat exchanger performance. Moreover, the review comprehensively covers the utilization of different nanoparticles and nanomaterial sizes in car radiators, highlighting advancements in real-time application. Additionally, it explores the use of various types of extended surfaces and nanofluids in different heat exchangers, providing a detailed analysis of their impact on heat transfer enhancement. The examination also includes a review of water-based nanofluids and their diverse applications in various heat exchangers, shedding light on the evolving landscape of nanofluid technology in the field. © 2024 Elsevier Ltd

Efficient thermal management system is crucial for maintaining optimal temperatures in a comprehensive range of applications, including buildings, electronic devices, the automobile industry, and solar PV systems. Spray cooling (SC) has emerged as a promising technique for effectively dissipating heat generated by these systems, offering rapid heat transfer rates with low energy requirements. This paper presents a comprehensive review of recent advancements in SC technology across multiple applications, such as solar panel cooling, fuel cells, electric vehicles, electronic devices, and the building sector. The review highlights the significant role of SC in achieving efficient thermal management and improving overall system performance. It discusses the capacity of SC systems to reduce the temperature and enhance thermal comfort levels effectively. Notably, the review emphasizes the impact of critical factors, including surface-to-nozzle distance, critical heat flux (CHF) stimulation, nozzle design, and nozzle angle, on the performance of SC systems. Furthermore, the work identifies key areas for future exploration and development, including the investigation of factors influencing CHF, such as the utilization of nanofluids in sprays, exploration of different angles of inclination, optimization of the number of nozzles, droplet size characterization, and considerations of economic feasibility. The findings underscore the immense potential of SC technology in diverse applications, highlighting its capability to enhance thermal management, reduce energy consumption, and optimize system performance. Continued research and development endeavors in this field are crucial for further advancements in SC systems, enabling their faster adoption in practical applications. © 2023 Elsevier Ltd

A cost-effective indirect cabinet-type solar dryer was designed and developed to remove the moisture in green peas until their moisture content reaches 14–15 % with minimal energy supplied from external sources. The green peas were placed beneath the absorber plate of the modified solar cabinet dryer (MSCD) thereby preventing its exposure to direct sunlight. The performance of MSCD was assessed at three different air velocities and was compared with a conventional solar cabinet dryer (CSCD) operated in passive mode. Experimentation showed that when hot air from the upper chamber of MSCD was fed to its lower chamber at 0.0406 kg/s, the dried green peas were free from shrinkage, uneven drying, and browning. However, when hot air was fed to the lower chamber of MSCD at 0.00585 kg/s and 0.027 kg/s the dehydrated green peas underwent shrinkage. At the same time, the green peas dried in CSCD underwent shrinkage, uneven drying, and browning despite its higher efficiency (about 13.5 %) and shorter span (2 h and 30 min) taken for drying when compared to MSCD. Hence, CSCD and MSCD operated at an air velocity of 0.00585 kg/s, and 0.027 kg/s was found to be not suitable for dehydrating green peas. The efficiency of MSCD when hot air from the upper chamber was fed to its lower chamber at 0.0406 kg/s was 10.64 % and the payback period was 0.47 years. © 2023 International Solar Energy Society

Food waste is primarily generated in marketplaces, agricultural fields, hotels, food manufacturers units, and halls. Food waste have a major impact on food security, quality and safety, economic development, and cause environment pollution. The improper disposal of food waste without proper treatments leads to generation of new diseases, unpleasant odour, air, water, and soil pollution. Nevertheless, food waste is a good substrate which can be disintegrated by digestion process because it exhibits more water contents and biodegradability. The conversion of food waste into biomethane is an appreciable solution in food waste management steps. This manuscript reviews the physico-chemical properties of food waste, various pretreatment methods of food waste to enhance the efficiency of anaerobic digestion (AD) process used to produce biomethane and discussed the impact of operational factors on biomethane production. Subsequently, the need for a biomethane upgradation using physical, chemical, and biological purification approaches was reviewed. In order to improve the efficiency of the anaerobic digestion (AD) process to a large-scale industrial level, the challenges and possible future developments needed to enhance biomethane generation from food waste were also reviewed significantly. © 2024 Elsevier Ltd

Heavy industries play a crucial role in the economic growth of India through their contribution towards meeting demand, including exports and GDP. Every functional unit of the production process related to hard-to-abate industries has to depend upon power sources for manufacturing the final product. The major power source for heavy industries namely power plants, iron and steel, cement, paper, and fertilizer are coal. During the process of energy conversion from coal through combustion, they produce a large amount of greenhouse gases. As production capacity is increased to meet the growing demand, it is essential to mitigate carbon emissions. There are many routes adopted by various sectors to decarbonize the production process. These include the use of alternative fuels, using the best available techniques, carbon capture utilization, and storage. Most of these techniques have shown positive impacts after implementation. In this study, the production process of each sector is analyzed to find the hotspots, the mitigation strategies followed by each industry, and mainly the use of green hydrogen as a power source. It elaborates on the routes of production of green hydrogen, the major challenges in the implementation part, the policy making of green hydrogen in India, its relationship to heavy industries, and how green hydrogen plays a role in net-zero emission goals. © 2024 American Chemical Society.

Bioenergy resources, when harvested sustainably, have the potential not only to satisfy the growing energy demand but can also aid in achieving a negative carbon footprint. The Intergovernmental Panel on Climate Change (IPCC) has also identified bioenergy resources as an effective tool to achieve zero emissions by 2050 because biomass can be valorized into various products, namely, producer gas, syngas, bioethanol, biomethanol, biochar, bio-oil, etc. by adopting different conversion pathways, thus, aiding in the reduction in consumption of fossil fuel, thereby decreasing the anthropogenic greenhouse gas (GHGs) emission into the atmosphere. However, it is necessary to analyze the economic viability of these biorefinery systems for the faster penetration of these products into the global market and to identify the bottleneck haunting its faster dissemination. In this regard, this chapter analyses the technical and economic factors which affect the biorefinery of woody biomass by employing thermo-chemical and bio-chemical conversion processes. © 2023 Elsevier Inc. All rights reserved.

The global nations are under pressure to develop a renewable and environmentally friendly fuel/technology from sustainable feedstock, such as woody biomass, to reduce greenhouse gas emissions and meet the energy demand. But several factors must be addressed to achieve the daunting task, which includes technological advancement, financial viability, environmental sustainability, and finally government backing in the form of sensible regulations and increased public awareness. To reduce the world's reliance on fossil fuels and ensure a sustainable future, biofuel policies are crucial. The production of biofuel from woody biomass makes the system not only to reduce the cost of the feedstock but also to decrement the dependency on first-generation feedstocks, which dominates the present biofuel market. Hence, this chapter deals with the need for governing bodies to draft an effective policy for the successful adoption of woody biomass-based biorefinery technologies to mitigate global emissions and to fulfill the growing energy demand thereby enabling a sustainable economy. © 2023 Elsevier Inc. All rights reserved.

The energy sector accounts for three-quarters of the greenhouse gas emission happening around the world. So, it is necessary to move toward a sustainable fuel with minimal carbon emissions to mitigate the rise in global temperature. Bioenergy is considered an effective resource to satisfy the rising global energy demand with minimal carbon emissions. The presence of proven and well-mature technology to convert biomass into various forms of fuels and chemical products provides an upper hand to bioresources over other energy sources. However, the rise in the cost of feedstocks, transportation cost of low-density bioresources, and lack of reliable biomass supply chain network has made them least preferred when compared to solar and wind energy technologies. Hence, it is important to access the scope for commercialization of biomass-based products, which will aid in framing policies to create a sustainable market for them. © 2024 Elsevier Inc. All rights reserved.

Carbon capture storage and utilization (CCSU) has the potential to become a key tool to mitigate climate change, thus, aiding in achieving the objectives of the 2015 Paris Agreement. Even though the relevant remediation technology has achieved technical maturity to a certain extent, implementation of CCSU on a larger scale is currently limited because of non-technical parameters that include cost, legalization, lack of storage reservoir, and market mechanism to penalize CO2 emitter. Among these, cost emerges as the primary barrier to the dissemination of CCSU. Hence, necessary policy frameworks and incentives must be provided by governing agencies to enable faster dissemination of carbon capture and utilization (CCU) and carbon capture and storage (CCS) globally. Meanwhile, strict implementation of a carbon tax across nations and market demand for products generated using captured CO2 can aid in the fast adoption of CCU and CCS. This review assessed the economic feasibility and sustainability of CCS and CCU technologies to identify the barriers to commercializing these technologies. © 2023 Elsevier B.V.

Hydrogen is considered as the fuel of the future not only because of its high energy density but also due to its zero-carbon emission potential during combustion. However, to achieve sustainable growth, the hydrogen generation process must be techno-economically feasible and have minimum carbon footprint. The techno-economic analysis (TEA) of various hydrogen generation process aids in identifying the effective bio-hydrogen generation process at minimal cost thereby aiding in faster dissemination of the system by attracting investors. Among the various techniques available for bio-hydrogen production, gasification was found to be most economical ($1.2/kg H2) followed by anaerobic digestion process ($1.25/kg H2). Meanwhile, after carrying out the life cycle analysis (LCA) of the different bio-hydrogen generation process, it was found that generation of bio-hydrogen by gasification of eucalyptus wood produced least carbon foot of −1.6 kg CO2eq./kg H2. Thus, the TEA and LCA of different biohydrogen production process also helps to identify the bottlenecks haunting the penetration of hydrogen in energy market which can be overcome by framing effective policies by the governing agencies. © 2023 Elsevier Ltd

Bioenergy with carbon capture and storage (BECCS) is gaining attention as an energy source and the most effective path to achieve negative CO2 emissions by photosynthesis and capturing CO2. However, BECCS has certain challenges and limitation which needs to be addressed to make the technology feasible. Concerns about food security, land, water use, and the possibility of large-scale implementation are critical in commercialization. As an emerging field, BECCS will need dynamic research and development over the next few decades, as well as strong policy backing, to clinch that it can be implemented on time for fulfilling the Paris agreement targets. The goal of this critical review is to find the impending obstacles that BECCS is facing, as well as the approaches to overcome them, while also emphasizing the advances in the field over the last decade. Detailed technology assessment is provided for a better understanding. © 2023 Elsevier Ltd

Woody biomass, the most abundant and high energy density bioenergy resource, is used inefficiently to satisfy the domestic heating and cooking demands of the people. Despite being a carbon-neutral source when harvested sustainably, the inefficient use of biomass to satisfy the cooking demand of marginalized people led to poor indoor air quality and causing respiratory health problems. Hence, it is necessary to identify a technology that enables the conversion of woody biomass into fuel that does not affect indoor air quality. In this regard, the conversion of woody biomass into biogas by anaerobic digestion emerges as the viable option. However, the recalcitrance nature of woody biomass necessitates a pretreatment before being fed to an anaerobic digestor, increasing the capital and operating cost of the biogas system. But usage of this technology to convert woody biomass to gaseous fuel can aid in sustainable development. The waste digested from the anaerobic digestor can be used as manure for agricultural crops in rural areas. Meanwhile, fly ash generated during the combustion of the woody biomass is also inhibited thereby resulting in an improvement in air quality. In this regard, this chapter presents the recent developments and factors affecting biogas production from woody biomass. © 2023 Elsevier Inc. All rights reserved.

Nutrient recovery systems can help to mitigate the negative effects of N and P in WW (wastewater), which when not recovered causes eutrophication in aquatic ecosystems. Using SimaPro (V9.3), the lifecycle assessment (LCA) of four nutrient recovery systems and sewage treatment plant (STP) were compared in this study. The findings showed that a fuel cell with a single-pot WW treatment system can function as a negative emission system with a global warming potential (GWP) of −234 gCO2 Eq./m3 of WW. Nutrient recovery reduces carbon footprint by 56–98% when compared to traditional fertilizers like diammonium phosphate (DAP) and urea. One of the main conclusions of this research was that single-pot systems perform better for the environment than add-on systems, which suggests that microalgae could perform better for the environment in a single-pot system. Recovering nutrients from WW not only improves self-reliance in the economy by decrementing the fertilizer import but also saves the environment. © 2023 Elsevier Ltd

Need for increasing the shelf life of agricultural produce using renewable energy based A decentralized system are significantly increasing. The solar air heating systems (SAHs) are efiiecnet and environment fridnly systems which are used for preserving agricultural produce thourgh the reduction of moisture content. However, these systems had poor thermal efficiency and the way for increasing the effeiciney are much need in the present era. This article presents the energy, exergy, and economic analysis of a modified solar air heater system (SAH). The proposed (modified) SAH has a V-corrugation absorber plate; the inner surface was modified using shot-blasting technology. This is the first study to experimentally investigate a modified SAH and compare the results with those of a conventional SAH. Additionally, an environmental and sustainability assessment of the SAH is presented. The SAH performance was tested at airflow rates ranging from 0.01 to 0.02 kg. sec−1. The proposed SAH achieved higher energy and exergy efficiencies (15% and 34%, respectively) than a conventional SAH at a flow rate of 0.02 kg. sec−1. Although the modification significantly improves the SAH performance, the performance must be further improved as the SAH has a low exergy efficiency. Through extensive experimental investigation, it was found that the modified SAH performs well in terms of energy, exergy, and economics. Pertaining to MFR of 0.01, 0.015, and 0.02 kg. sec−1 the average energy efficiency of the modified SAH was increased by around 2.4%, 3.1%, and 5.8% greater than that of the conventional SAH, respectively. Concerning the MFR of 0.01, 0.015, and 0.02 kg. sec−1 the average exergy efficiency (AEE) was augmented about 0.21, 0.36, and 0.70 higher in the modified SAH, respectively. With MFRs of 0.01, 0.015, and 0.02 kg. sec−1, the modified SAH system mitigates approximately 10.3 tons, 18.06 tons, and 28.7 tons of CO2/year, respectively. The enviroeconomic factors of the modified (shot blasted) SAH were augmented by about 23.4%, 15.1%, and 18.2% compared with the conventional SAH at MFRs of 0.01, 0.015, and 0.02 kg. sec−1, respectively. © 2022 The Institution of Chemical Engineers

Increases in population and urbanization leads to generation of a large amount of food waste (FW) and its effective waste management is a major concern. But putrescible nature and high moisture content is a major limiting factor for cost effective FW valorization. Bioconversion of FW for the production of value added products is an eco-friendly and economically viable strategy for addressing these issues. Targeting on production of multiple products will solve these issues to greater extent. This article provides an overview of bioconversion of FW to different value added products. © 2022 Elsevier Ltd

This review provides an update on the state-of-the art technologies for the valorization of solid waste and its mechanism to generate various bio-products. The organic content of these wastes can be easily utilized by the microbes and produce value-added compounds. Microbial fermentation techniques can be utilized for developing waste biorefinery processes. The utilization of lignocellulosic and plastics wastes for the generation of carbon sources for microbial utilization after pre-processing steps will make the process a multi-product biorefinery. The C1 and C2 gases generated from different industries could also be utilized by various microbes, and this will help to control global warming. The review seeks to expand expertise about the potential application through several perspectives, factors influencing remediation, issues, and prospects. © 2022 Elsevier Ltd