Energy nexus最新文献

This research revolves around the modeling and optimization of an innovative geothermal system powered by geothermal energy. The system incorporates a modified Organic Rankine Cycle to efficiently produce electricity, hydrogen, cooling, and heating. The study is specifically tailored for South Korea, with a focus on the city of Ulsan. The primary objective of this geothermal system is to generate essential products for residential buildings without contributing to carbon emissions or environmental pollution. The modeling aspect of this research is conducted using EES software, while optimization efforts are aimed at enhancing performance by optimizing the exergy efficiency and reducing costs. The response surface method (RSM) and Design Expert optimization software are employed for this purpose. The optimal results demonstrate that, in its most efficient state, the system can achieve an impressive exergy efficiency of 45.382 % and operate at a cost rate of 50.414 $/h. The economic analysis underscores that the modified ORC unit bears the highest system cost, amounting to 49.47 $/h. The findings reveal that the suggested geothermal system performs exceptionally well in cities with weather conditions akin to Ulsan. In other regions across the globe, it has the potential to significantly enhance cost-effectiveness and exergy efficiency. The research concludes by evaluating the system's capacity to provide electricity, heating, and cooling for residential complexes within the study areas, highlighting its potential for addressing diverse energy needs in urban settings while prioritizing sustainability and environmental responsibility. The results showed that the study system can produce 3,982,413.6 kWh of heating, and 4,555,440 kWh of cooling during the year. The environmental results showed that by producing 4088.72 MWh of electricity annually in the city of Ulsan, South Korea, it is possible to help the expansion of 4 hectares of green space per year. Also, by reducing carbon dioxide emission by 834.09 tons of CO2, the proposed system avoids the cost of 20,018.3 $ on the environment. The proposed geothermal system can supply the electrical needs of 401 people in Ulsan city during the year.

The use of novel and inexpensive catalysts as replacements for platinum is desirable. In this study, we demonstrate for the first time that cost-effective metal oxide nanomaterials and the conductive polymer polyaniline (PANI) can be directly chemically synthesized on carbon microfiber electrodes to improve the performance of lake sediment inoculated MFCs. Nanomaterial of MnO₂, MnO₂/polyaniline (PANI), ZnO/NiO and ZnO/NiO/PANI attachments were directly chemically synthesized on the carbon material and used as cathode electrodes. The maximum power densities recorded for the different treatments were; MnO₂ 78.5 mW/m², MnO₂/PANI (Polyaniline) 141.6 mW/m², ZnO/NiO 67.6 mW/m², and ZnO/NiO/PANI 129.4 mW/m². Current and power densities were more than six-fold higher in ZnO/NiO/PANI and MnO₂/PANI nanoparticle modified cathodes compared to the control MFCs with no catalyst and more than 2.5 fold higher compared to Pt loaded conventional cathodes. In-excess of 50-fold reductions in catalyst application costs to obtain a unit amount of power was demonstrated with the novel nanomaterials direct deposition method when compared to traditional catalysts such as Pt. This study demonstrates that nanomaterials-incorporated carbon microfiber cathodes bring about significant enhancements to power densities and may potentially have applications in cost-effective MFCs.

Biodiesel as a renewable and environmentally friendly fuel can be considered an alternative to fossil fuel in industries, and one of the promising approaches to developing biodiesel yield is its production in microreactors. However, the produced quantity from microreactors is limited which necessitates higher throughput microreactors to be produced, maintaining the high yield of biodiesel. Therefore, this study investigated the transesterification of waste cooking oil (WCO) with methanol in the presence of sodium hydroxide as the catalyst using a novel branched microreactor, used for higher throughput applications. Thus, a novel four-micro serpentine-based microreactor was designed and fabricated with no external tubing. Biodiesel is produced in the fabricated microreactor and the Box-Behnken Design method (BBD) in Minitab software was used to design the experiments with different operating conditions: methanol to oil molar ratio (6:1–12:1), catalyst concentration (0.5–1.5 wt%), and reaction temperature (55–65 °C) to optimize the biodiesel volume yield in the designed microreactor. The optimum biodiesel yield using GC–MS analysis was found to be 82.8 % at a methanol to oil molar ratio of 12:1, 1.5 wt% catalyst concentration, and reaction temperature of 59.4 °C while maintaining the reactants’ inlet flow rate of 20 µL/s. Production of up to 35 mL biodiesel was collected in 30 min only. In addition, the microreactor achieved up to 97 % conversion at inlet flow rates of 8.5 µL/s.

This review article gives a short overview of the basic principle and criteria to evaluate the performance of dye-sensitized solar cells. Experimental measurements such as the short-circuit current density, open-circuit photovoltage, fill factor, energy conversion efficiency, light harvesting energy and band gap, are discussed and formulas to measure them are provided. In addition, density functional theory calculated parameters often used to evaluate dyes for dye-sensitized solar cells are explained and formulated. These include light harvesting energy, oscillator strength, injection driving force, regeneration driving force, driving force for charge recombination, excited state lifetime, the character (e.g. metal based, ligand based, π, π* etc.) and energy of the highest occupied and lowest unoccupied molecular orbital, natural transition orbitals, band gap and reorganization energy for electron and hole. The relationship between the density functional theory calculated and experimentally measured parameters is explained. An enhanced short-circuit current density and improved performance of dye-sensitized solar cells are anticipated with higher calculated values for light harvesting efficiency, driving force for electron injection and regeneration, and lower calculated values of reorganization energy. Additionally, higher calculated values of the dipole moment of the dye perpendicular to the TiO₂ semiconductor surface are expected to enhance the open-circuit photovoltage, consequently contributing to the overall performance of dye-sensitized solar cells. Figures to illustrate the different measurable parameters and selected examples from the literature are provided. These techniques can be employed in subsequent experimental and theoretical studies to validate potential new dyes for use in dye-sensitized solar cells.

A three-layer business model canvas was applied to clarify the environmental, economic, and social impacts of introducing oil-water separation equipment (OWSE) used in restaurants and food processing factories. Introducing high-performance OWSE can change the social structure of manufacturers and residents of sewerage development areas and provide economic benefits to companies. Based on the data of a ramen restaurant in Miyagi, Japan, evaluated the economic effect of introducing OWSE resulted in the total initial cost and maintenance was 1,032USD/year less than the cost of the sewage fee. Therefore, the proposed equation can be used to evaluate the economic effects of introducing OWSE.

Cryptocurrency is rapidly emerging as a prominent player in the global financial system, characterized by its decentralized nature and the absence of centralized government oversight. However, this autonomy raises significant environmental concerns primarily stemming from the energy-intensive mining process. Crypto mining, central to the creation of new coins and transaction validation, results in substantial carbon emissions and energy consumption. This study employs bibliometric analysis using RStudio to scrutinize the data sourced from the Scopus database. Data selection adhered to specific inclusion criteria, focusing on research articles and documents in the English language. Exclusion criteria targeted the elimination of review papers, conference reviews, short surveys, notes, and articles in languages other than English. China emerges as the foremost contributor with a frequency of 348 and a total citation count of 1259, followed by the USA with 594 citations. Notably, the keywords "blockchain" and "bitcoin" surface most frequently, occurring 293 and 148 times, respectively. The study posits that China's decision to ban cryptocurrency due to economic concerns has likely contributed to heightened global awareness of cryptocurrencies. In contrast, the USA has actively embraced cryptocurrencies, fostering their widespread circulation. Consequently, these two countries have emerged as leading contributors to energy consumption in the cryptocurrency sector. Blockchain, originally a broad concept, has found applications in diverse domains such as marketing, finance, healthcare, supply chain, and the Internet of Things (IoT). This widespread adoption has expanded the scope of energy consumption considerations from cryptocurrencies to encompass blockchain technology as a whole. Future research should focus on mining regulation, alternative mechanisms, renewable energy sources, technological advancements, and carbon offsetting solutions. The article also addresses its limitations and the future scope of the study in detail.

To achieve the net-zero greenhouse gas emissions goal by 2050, it is essential for local municipalities to clarify the current state of renewable energy (RE) development, energy balance, and future development directions. Thus, an optimal energy supply system scheme with a coordination function between municipalities has been designed for Fukuoka Prefecture. We initially examined the spatial distribution of current RE supply and energy balance at the municipality level and estimated the total supply potential of Agri-Voltaic to be approximately 4145 GWh year⁻¹. In our analysis, we found that in 2020 (the current scenario), the share of RE supply by municipalities relative to demand ranged from 3 % to 267 %, with an average of 32 %. Grid power accounted for 84 % of the total demand. However, considering factors like a declining birth rate, an aging population, and energy saving initiatives assumed for 2050 (the future scenario), we estimate a decrease in total energy demand from the current level of 30,950 to a future level of 24,339 GWh year⁻¹. From an emissions perspective, optimizing the promotion of additional RE sources and coordinating RE usage between municipalities in the future will help achieve the goal of 100 % RE supply, meet the future energy demand at the prefecture level, and support regional decarbonization efforts (emission reductions: 7871 GgCO₂).

The chemical industry is directly or indirectly connected with almost every industrial process and holds a crucial place in the economic and social advancement of India. At the same time it is however, the second highest energy intensive industry in the country. Thus, we attempt to look into the factors that affect the energy intensity of Indian chemical industry. We collect a panel dataset including a total of 2613 chemical firms for the period 2010 to 2021 for our analysis. We carry out our empirical testing under both linear and non-linear framework by employing fixed effect regression and panel quantile regression methods respectively.

We find that energy intensity for the sample chemical firms increases due to poor labour productivity, huge plant and machinery, outsourcing operations, and more use of IT-enabled services. On the other hand, use of better quality raw material and advanced technology can help optimising the energy intensity. We also discover that profitable firms and firms larger in size are energy efficient. Based on the findings, we suggest professional training programs and vocational skill development programs for enhancing labour productivity. Profitable firms are suggested to invest in technological up-gradation and energy saving technology. We believe the findings of the study can provide a portfolio of variables to the managers and policy makers in order to diversify their attention to find all possible ways to reduce energy intensity of the Indian chemical firms.

Presence of trace metal pollutants in the aquatic system is a worldwide foremost concern. The present investigation was an attempt to find out the novel biosorbent for the removal of Cadmium(CdII) from contaminated water. The leaf of Sesbania bispinosa was screened out as a potential Cd(II) removing biosorbent from thirty different natural biomasses by physico-chemical and sorption process characterizations. Biosorption capacity of S. bispinosa was determined by batch mode biosorption method with the functions of solution pH, contact time, biosorbent dose and initial Cd(II) concentration. Obtained results were analyzed for isotherm and kinetic study. The S. bispinosa biosorbent exhibited the biosorption equilibrium of Cd(II) uptake in 30 min. At pH 4, biosorbent dose of 1 g/L was sufficient for maximum Cd(II) uptake. Scanning Electron Microscopy (SEM) images and Fourier Transform Infrared Spectroscopy (FTIR) spectra confirmed the favourable sorption surface characteristics. The data also demonstrated that Freundlich isotherm (R²=0.998) is the better fitted model compared to Langmuir model and the maximum sorption capacity was found to be 33.33 mg/g. Suitabilty of pseudo second order reaction pathway was observed during the kinetic study. Most especially, The selected biosorbent is ascertained effective in removing multimetals [Cd(II) - 67.51 %, Cr(VI) – 40.36 %, Pb(II) – 100 % and Cu(II) – 59.01 %] from a quaternary aqueous solution of Cd(II), Cr(VI), Pb(II) and Cu(II) mixture and spent biosorbent can be easily regenerated by applying 0.1 M HCl solution as a desorbing agent. It, therefore, could be concluded that leaves of S.bispinosa might be a low-cost and environmentally sound novel biosorbent for the treatment of Cd(II) contaminated water.