Sustainable Energy Utilization Research Articles

Three-dimensional hybrid carbon nanocomposite-based intelligent composite phase change material with leakage resistance, low electrical resistivity, and high latent heat

The development of shape-stabilized composite phase change materials (PCMs) is critical for realization of efficient thermal energy management systems and sustainable energy utilization. Herein, we designed an intelligent, multifunctional, organic composite PCMs with a three-dimensional (3D) hybrid nanocomposite and n-pentadecane. The 3D hybrid material was designed via integration of exfoliated graphene nanoplatelets (xGnP) and multiwalled carbon nanotubes (CNTs). The hybrid nanocomposite exploited the distinctive attributes and synergistic effect of each the supporting component for the well-designed composite PCMs to demonstrate high physical and thermochemical responses. The obtained composite PCM presented a high loading ratio of 82.7% and latent heat of 150.9 ± 0.9 J/g (which is 36% higher than that of the pristine xGnP-supported PCMs) owing to favorable space availability for phase change transformation with the aid of the CNTs skeleton. Moreover, the composite exhibited reduced supercooling (56.6% lower than that of CNTs-supported n-alkane), high leakage resistance capability, and thermal stability performance. The composite PCMs can also enable realization of a thermoelectric conversion system (lower than 101 Ω m resistivity, which is a reduction of more than six orders of magnitude compared with pristine n-alkane) and exhibit high thermal diffusivity (up to 3.707 mm2/s), indicating several practical applications thereof.

Deep Eutectic Solvents for Boosting Electrochemical Energy Storage and Conversion: A Review and Perspective

AbstractThe pursuit of sustainable energy utilization arouses increasing interest in efficiently producing durable battery materials and catalysts with minimum environmental impact. As green, safe, and cheap eutectic mixtures, deep eutectic solvents (DESs) provide tremendous opportunities and open up attractive perspectives as charge transfer and reaction media for electrochemical energy storage and conversion (EESC). In this review, the fundamental properties of DESs are first summarized. Then, the important roles that DESs play in various EESC technologies including advanced electrolytes for batteries/supercapacitors, media for the preparation of electrode materials and catalysts, and extracting agents for battery recycling are systematically reviewed. A particular focus is placed on the fundamental understanding of structure–composition–property–performance relationships. Finally, the challenges for the controllable design of DESs for EESC applications and future developments are presented. This review is expected to shed light on developing advanced DESs for next‐generation EESC systems.

Enhanced thermal energy storage performance of salt hydrate phase change material: Effect of cellulose nanofibril and graphene nanoplatelet

Thermal energy storage (TES) has attracted intense attention because of its positive contribution to sustainable energy utilization. To improve the TES performance of sodium acetate trihydrate (SAT), the combined use of cellulose nanofibril (CNF) and graphene nanoplatelet (GNP) was investigated to tackle the phase separation problem and to improve the thermal conductivity of SAT. Phase stability and rheology tests revealed that adding 0.8% of CNF to SAT increased viscosity, enhanced solid-like rheological behavior, and successfully eliminated phase separation. Meanwhile, the amphiphilicity of CNF facilitated the dispersion of GNP. Sodium phosphate dibasic dodecahydrate (DSP; Na2HPO4·12H2O) was selected as the nucleating agent, which reduced the supercooling degree of SAT to 2.1 °C. Phase change materials (PCMs) were prepared by simply blending GNP pre-dispersed with CNF, DSP, and SAT. Due to the excellent thermal performance of GNP and its good dispersion by CNF, the prepared PCM composites showed enhanced thermal conductivity compared with that of pure SAT. Thermal reliability testing indicated that the melting point and enthalpy of the prepared PCM composites decreased after 100 melting/freezing cycles. Overall, PCM composites with enhanced performance were fabricated based on renewable, bio-based, and biodegradable nanocellulose. These composites can be used for certain TES applications.

Optimal Stochastic Operation of Integrated Electric Power and Renewable Energy With Vehicle-Based Hydrogen Energy System

The renewable energy-based hydrogen production can lead to the integrated electric power and hydrogen system (IPHS) and offer a pathway to a sustainable energy utilization. Hydrogen is mainly transported via hydrogen tube trailers (HTs), making the hydrogen energy system (HES) operation quite different from those of other energy technologies. This paper proposes an optimal IPHS operation strategy which utilizes HT for transportation. The proposed strategy coordinates hydrogen generation, transportation, and storage stages considering constrained operations of electric power system (EPS), transportation system, and variable renewable energy. The proposed solution method is based on the alternating direction method of multipliers (ADMM) in which HES and EPS constraints are managed individually and the respective solutions are coordinated accordingly. The case studies using the modified IEEE-RTS79 have verified the validity of the proposed IPHS model and its solution method and confirmed the necessity of considering HES in enhancing the EPS operation. The synergies between EPS and HES are studied via numerical examples and the impact of the flexibilities in hydrogen generation, transportation and demand are highlighted.

Ensemble-boosting effect of Ru-Cu alloy on catalytic activity towards hydrogen evolution in ammonia borane hydrolysis

The development of high-efficient and economical catalysts is a challenging problem for the utilization of sustainable hydrogen energy. Alloying noble metal with non-noble metal is a promising strategy to achieve high catalytic activity and stability of catalysts. Herein, highly dispersed Ru-Cu alloy nanoparticles were successfully fabricated via solid-surfaces-organic-pyrolysis on N-doped carbon coating TiO2 towards hydrogen evolution in NH3BH3 hydrolysis. Ru-Cu alloys with various molar ratios exhibit markedly enhanced catalytic activity than monometallic counterparts. The optimized Ru0.6Cu0.4/TiO2@C-N catalyst achieves an excellent TOF of 626 molH2 molRu−1 min−1 at room temperature. Experimental analysis and DFT calculation reveal the existence of ensemble-boosting effect between Ru and Cu. Multiatomic active sites in alloy significantly promote hydrogen evolution in NH3BH3 hydrolysis. This research provides further understanding of catalytic mechanism and the rational design of high-efficient and economical bimetallic nanocatalysts.

Study on an Oscillating Water Column Wave Power Converter Installed in an Offshore Jacket Foundation for Wind-Turbine System Part I: Open Sea Wave Energy Converting Efficiency

This study is focused on the wave energy converter of an oscillating water column (OWC) system that is integrated with a jacket type infrastructure applied for an offshore wind turbine system. In this way, electricity generation by both wind power and wave power can be conducted simultaneously to maximize the utilization of sustainable energy. A numerical analysis was performed in this research to model and simulate the airflow response and evaluate the converting efficiency of wave energy from an OWC system integrated with an offshore template structural system. The performance of the system including the generating airflow velocity, air-pressure in the chamber, generating power and then the converting efficiency of power from waves are all analyzed and discussed in terms of the variations of the OWC system’s geometrical parameters. The parameters under consideration include the exhale orifice-area of airflow, gate-openings of inflow water and the submerged chamber depth. It is found that from the analytical results the performance of the OWC wave energy converter is influenced by the dimensional parameters along with the design conditions of the local environment. After a careful design based on the in-situ conditions including water depth and wave parameters, an open OWC system can be successfully applied to the template structure of offshore wind power infrastructure as a secondary generating system for the multi-purpose utilization of the structure.

Energy Efficiency Enhancement and Climate Change Mitigations of SMEs through Grid-Interactive Solar Photovoltaic System

According to the International Energy Agency’s estimation, Indian primary energy demand is expected to increase by about 1250 Mtoe and 1500 Mtoe by 2030. The 3 M management concept now changed into a 4 M management concept that includes energy management. In the case of energy management, the electrical energy sector assumes critical importance. An energy cost occupies nearly 30-40% of the production cost in small and medium-size enterprises (SMEs). Bureau of Energy Efficiency (BEE) has initiated a separate energy efficiency intervention to the SME’s, where the energy-efficient technologies, operational procedures, and proper awareness programs to SMEs are stated. This paper discusses the complete electrical energy audit on a small-scale Siddha and Ayurveda medicine industry. The traditional medicine manufacturing technologies make the process complex (process loads are intermittent/interlinked) during analysis. Hence, the detailed energy auditing/conservation studies on the power factor/harmonics were carried out without affecting Indian traditional medicine manufacturing technology. The postauditing design and installation of an intelligent controller by considering the intermittent/interlinked loads are carried out, and the effectiveness of the intelligent controller is ascertained with the energy conservation and the carbon emission reduction of SME. In addition, the climate change mitigation is ensured through the design and deployment of grid-interactive rooftop solar photovoltaic power plant using Solar Pro v4.5 (Photovoltaic System simulation software) with the power analysis, economic analysis and life cycle carbon emission of the proposed plant. The proposed solar photovoltaic power plant ensures energy self-sufficiency and sustainable energy utilization by carbon emission reduction on electricity utilization of SMEs.

Carbon dots modified Ti3C2Tx-based fibrous supercapacitor with photo-enhanced capacitance

The energy crisis has always been a widely concerned problem. It is an urgent need for green and renewable energy technologies to achieve sustainable development, and the photo-assisted charging energy storage devices provide a new way to realize the sustainable utilization of solar energy. Here, we fabricated a photo-assisted charging fibrous supercapacitor (NM2P1) with Ti3C2Tx-based hybrid fibre modified by nitrogen-doped carbon dots (NCDs). The NM2P1 fibre provides a volumetric capacitance of 1,445 F·cm−3 (630 F·g−1) at 10 A·cm−3 under photo-assisted charging, which increases by 35.9% than that of dark condition (1,063 F·cm−3/464 F·g−1). Furthermore, the NM2P1 fibrous supercapacitor device shows that the maximum volumetric energy density and volumetric power density are 18.75 mWh·cm−3 and 8,382 mW·cm−3. Notably, the transient photovoltage (TPV) test was used to further confirm that NCDs as a photosensitizer enhance the light absorption capacity and faster charge transfer kinetics of NM2P1 fibre. This work directly exploits solar energy to improve the overall performance of supercapacitor, which opens up opportunities for the utilization of renewable energy and the development of photosensitive energy equipment.

Techno‐economic assessment and optimization of a standalone residential hybrid energy system for sustainable energy utilization

Nowadays the whole world is striving to achieve energy security and sustainable development through sustainable utilization of cleaner energy resources. But due to the rapidly rising population caused by the unprecedented urban development, it has created imbalances of energy supply and demand. Hybrid energy systems have emerged as a promising source to augment existing energy infrastructure for sustainable energy supply and to reduce the impact of challenges posed by the energy scarcities. There have been continuous requests from the urban sector for additional energy resources, but the energy generation involves a complex phenomenon. In India also, there are abundances of rising energy demands from various sectors over the regions, and these demands cannot be fulfilled further due to the limitations of the energy generation grids. As a result, an approach is required to offer additional energy resources beyond the use of diesel generator (which increases environmental pollution). Recently due advancement in hybrid energy systems consisting of non-renewable & renewable or renewable & renewable or non-renewable & non-renewable, it provides a scope to understand the various configuration of the hybrid energy system for past trends, present status and future scenarios. The investment in energy technologies is critical to be evaluated with techno-economic feasibility analysis for resource efficiency optimization. Hence, the main objective of this work is to propose an optimal system configuration for urban residential standalone hybrid energy systems to fulfil the electrical energy requirement, which is technically and economically reliable & feasible. The current work accounts for scaling up the existing energy system with proper implementation. The simulations results show that expected average energy requirements of 5 kWh/day with a peak of 818 W for a typical household can be met with proposed configuration (with components like solar PV, wind turbine, power generator [diesel] and battery backup system). The data simulation and optimization technique for a monthly profile of wind, solar, and excess energy generation over HOMER simulation toolkit offer the potential to generate excess electricity of 19.3%. Techno-economic assessment of the system shows that the proposed system offers more economical and performance benefits. This study also articulates the need to propose a better energy system structure with basic energy grid extension as a cost-effective solution for sustainable development. Similar kind of assessment will offer a useful decision support system for tropical countries to guide future researchers in energy studies.

Progress in Photocatalysis of g-C3N4 and its Modified Compounds

Recently, graphitic carbon nitride (g-C3N4), a polymeric semiconductorhas been widely used as a low-cost, stable, and metal-free visible-light-active photocatalyst in the sustainable utilization of solar energy, such as water splitting, organic photosynthesis, and environmental remediation, which has attracted world wide attention from energy and environmental relative fields. Base on analysis of structure and theoretical calculation, the reasons that g-C3N4 can be used as a non-metallic catalyst were discussed in this paper. Some group's research jobs that metal-supported g-C3N4, metal-supported g-C3N4/organnic semiconductor compound and heterogeneous junction adjust the semiconductor electronic band structure have been summarized. And the mechanism, effect factors, and research developments on the reaction of organic degradation by photocatalytic and splitting water for hydrogen revolution catalyzed by above-mentioned modified g-C3N4 were emphatically analyzed. Finally, the prospects for the development of highly efficient g-C3N4 based photocatalysts are also discussed.

NMB4.0: development of integrated nuclear fuel cycle simulator from the front to back-end

Nuclear Material Balance code version 4.0 (NMB4.0) has been developed through collaborative R&D between TokyoTech&JAEA. Conventional nuclear fuel cycle simulation codes mainly analyze actinides and are specialized for front-end mass balance analysis. However, quantitative back-end simulation has recently become necessary for considering R&D strategies and sustainable nuclear energy utilization. Therefore, NMB4.0 was developed to realize the integrated nuclear fuel cycle simulation from front- to back-end. There are three technical features in NMB4.0: 179 nuclides are tracked, more than any other code, throughout the nuclear fuel cycle; the Okamura explicit method is implemented, which contributes to reducing the numerical cost while maintaining the accuracy of depletion calculations on nuclides with a shorter half-life; and flexibility of back-end simulation is achieved. The main objective of this paper is to show the newly developed functions, made for integrated back-end simulation, and verify NMB4.0 through a benchmark study to show the computational performance.

Ammonia for Dairy Farms – A Sustainable Energy Utilization Technology

Ammonia for Dairy Farms – A Sustainable Energy Utilization Technology

Shear Induced Seepage and Heat Transfer Evolution in a Single-Fractured Hot-Dry-Rock

In the enhanced geothermal system (EGS), the injected fluid will induce shear sliding of rock fractures (i.e., hydroshearing), which consequently, would increase the fracture aperture and improve the heat transfer efficiency of the geothermal reservoir. In this study, theoretical analysis, experimental research and numerical simulation were performed to uncover the permeability and heat transfer enhancement mechanism of the Hot-Dry-Rock (HDR) mass under the impact of shearing. By conducting the direct shear test with the fractured rock samples, the evolution process of fracture aperture during the shearing tests was observed, during which process, cubic law was adopted to depict the rock fracture permeability. To investigate the seepage characteristics and temperature distribution of the fractured HDR under the influence of shearing, a simulation study of shear-seepage-heat transfer in a fractured rock mass has been conducted to validate the observed shear-induced fracture dilation during the direct shear test. The results demonstrate that (1) the hydroshearing increases the dilation of granite fracture and enhances the permeability of the HDR rock mass, while the temperature around the HDR fracture will reduce. (2) Fracture roughness is of vital importance to enhance the permeability during the shearing tests. To be more specific, a rougher fracture always implies a higher permeability and a greater heat extraction efficiency. (3) The shear induced heat extracting efficiency is dominated by the increased fluid flux in the earlier period of the EGS reservoir, and this efficiency is controlled by the outlet water temperature since the fluid flux becomes stable after the shearing test. Therefore, balancing the hydroshearing enhanced heat extraction efficiency and EGS reservoir lifespan would be significant to the sustainable development and utilization of geothermal energy

A Simple Method for Synthesizing Highly Active Amorphous Iridium Oxide for Oxygen Evolution under Acidic Conditions.

Water splitting for hydrogen production has been recognized as a promising approach to store sustainable energy. The performance of this method is limited by the oxygen-evolution reaction. Herein, an approach for synthesizing a highly active oxygen-evolving catalyst by a one-step, low-cost, environmentally friendly, and easy-to-perform method is presented, which works by using iridium metal as the anode at a relatively high potential. The obtained IrOx /Ir interface showed an overpotential of 250 mV at 10 mA cm-2 in 0.1 m HClO4 and remained stable under electrochemical conditions. The IrOx that was mechanically separated from the surface of IrOx /Ir metal after operation showed a threefold increase in activity compared to the current benchmark IrO2 catalyst. Various characterization analyses were used to identify the structure and morphology of the catalyst, which suggested nanosized, porous, and amorphous IrOx on the surface of metallic Ir. This synthetic approach can inspire a variety of opportunities to design and synthesize efficient metal oxide-based electrocatalysts for sustainable energy conversion and utilization.

Metal-Organic Phase-Change Materials for Thermal Energy Storage.

The development of materials that reversibly store high densities of thermal energy is critical to the more efficient and sustainable utilization of energy. Herein, we investigate metal-organic compounds as a new class of solid-liquid phase-change materials (PCMs) for thermal energy storage. Specifically, we show that isostructural series of divalent metal amide complexes featuring extended hydrogen bond networks can undergo tunable, high-enthalpy melting transitions over a wide temperature range. Moreover, these coordination compounds provide a powerful platform to explore the specific factors that contribute to the energy density and entropy of metal-organic PCMs. Through a systematic analysis of the structural and thermochemical properties of these compounds, we investigated the influence of coordination bonds, hydrogen-bond networks, neutral organic ligands, and outer-sphere anions on their phase-change thermodynamics. In particular, we identify the importance of high densities of coordination bonds and hydrogen bonds to achieving a high PCM energy density, and we show how metal-dependent changes to the local coordination environment during melting impact the entropy and enthalpy of metal-organic PCMs. These results highlight the potential of manipulating order-disorder phase transitions in metal-organic materials for thermal energy storage.

Improving Regulation and the Role of Natural Risk Knowledge to Promote Sustainable Low Enthalpy Geothermal Energy Utilization

The use of geothermal energy resources to support anthropogenic activities have a long-lasting tradition, renewed in recent decades with the increasing use of low enthalpy geothermal energy (LEG) with combined systems of heat pumps and geothermal exchange, exploiting the enormous thermal capacity and very low temperature variability of subsoil, including rocks and water. The further potential global increase of LEG use could be enormous, although LEG is already the main geothermal energy sources in Europe, contributing significantly to reach 2030 UN sustainable development goals (SDGs) on renewable energy resources, as a further leg to support all necessary efforts for these scopes. This research pursues LEG spreading improving knowledge on limitations of guidelines, technical regulations and/or laws, briefly rules, especially in terms of potential risks or limitations due to environmental constrains or natural phenomena. A global documentary research, including scientific articles, books, technical reports from qualified institutions, technical standards, guidelines, regulations, and laws, was realized with three different groups of keywords. A total of 161 documents were selected after some steps, including quality check. Identical English and Italian keyword sets were used to span from an international global scale to the complex local scale which characterizes the Italian experience. A complex sheet was filled in for each document, supporting data discussion, planned with a geographical criterion, from global to local. The system of rules resulted worldwide inhomogeneous and complex, with high differences from countries, nations or regions, also at local scale. The low quality or the absence of simple and careful “rules” emerged an important obstacle to LEG diffusion that can guarantee sustainability and the absence of natural risks. Main virtuous systems of rules were recognized as very useful to promote LEG spreading but these are still uncommon. The discussion of optimal experiences and the overview of potential natural risks due to LEG complete the paper.

Production of Bio-Hydrogen from Agricultural residues : A Contemporary Review

With the increase in usage of bio-products of all sorts in the modern world, the waste obtained during the production phases has been a major concern for over a period of time. The accumulation of these wastage not only enhances various kinds of pollution, but also increases the carbon footprint. Considering these negative impacts brought about by poor maintenance of these wastages and advancements in the field of utilization of sustainable and renewable energy, it is very important to produce bio-hydrogen due to the limitations of using industry-produced hydrogen. Hydrogen, though having many advantages, like being environmentally friendly and highly efficient when used as a fuel, has been neutralized by certain drawbacks such as production of it in industrial set up is found to be expensive and the storage process is tedious because of its flammable nature. Therefore, production of bio-hydrogen is found to be vital. In our paper, we have touched upon various methods of preparation of bio-hydrogen from the by-products of the farms such as corn stover, corn straw and rotten apple. Production of bio-hydrogen from micro algae has also been stressed upon as it has been found be one of the most efficient method. But, most of the analysis has been done on corn stover based on ambient atmospheric conditions, factors that affect the process and comparison between photo fermentation, dark photo fermentation and dark fermentation has also been judged as an important criterion for enzyme saccharification. Another important method of production of production of hydrogen using tequila vinasses in presence of charcoal by dark fermentation process has also been reviewed in this paper

Sunlight-induced uranium extraction with triazine-based carbon nitride as both photocatalyst and adsorbent

Extracting uranium from high salinity seawater at ultralow concentrations would beneficially contribute to the sustainable utilization of nuclear energy, but it poses a significant challenge. Here we report a sunlight-driven photocatalysis-assisted extraction (SUPER) method by utilizing a bifunctional carbon nitride material, CN550, which has shown about a tenfold improvement in both adsorption capacity and photocatalytic activity compared to g-C3N4. Uranyl ions could be captured on the surface of CN550, and then deposited as metastudtite nanoparticles with light illumination. Compared with the pure physicochemical adsorption (PA) method, a tenfold higher uranium extraction capacity, up to 1556 mg g−1, has been attained. Additionally, a 25 times improvement of the partition coefficient (PC), from 0.312 to 7.778 L g−1, has also been achieved. In spiked real seawater, the extraction capacity can still achieve more than 1000 mg g−1, and the SUPER method has been found to work under natural sunlight illumination as well.

The FeN3 Doped Fluorographene for N2 Fixation: A Density Functional Theory Study

AbstractThe ammonia synthesis under ambient condition is of significance for sustainable energy utilization. Herein, the nitrogen reduction reaction (NRR) on FeN3 embedded graphane and fluorographene are investigated by density functional theory calculations. Our results indicate that the functional fluorographene accelerates electrocatalytic N2 fixation with an onset‐potential of 0.97 V via alternating mechanism, being superior to the graphane counterpart. Furthermore, the fluorination alleviates the H poisoning and increases NRR selectivity. The improved performance is originated from the strong electron‐withdrawing of the F decoration. Moreover, the inferior NRR performance of the FeN3 decorated graphane indicates the infeasibility as the NRR electrode, reasonably avoiding the experimental attempt. This finding opens up the new design for the carbon‐based electrocatalysts with high efficiency of NH3 synthesis.

Coupling 0D and 1D Carbons for Electrochemical Hydrogen Production Promoted by a Percolation Mechanism.

Developing hydrogen evolution reaction (HER) electrocatalysts with high activity, durability and moderate price is essential for sustainable hydrogen energy utilization. Here, the facile coupling of carbon dots (CDs, 0D carbon materials) and carbon fibres (CFs, 1D carbon materials) for enhanced electrochemical hydrogen production was demonstrated. Electrochemical tests revealed that the CD/CF catalysts showed outstanding catalytic activity with a small overpotential of 280 mV at the current density of 10 mA cm-2 , a small Tafel slope of 87 mV dec-1 and prominent durability. Percolation theory was for the first time introduced to interpret the catalytic mechanism of the CD/CF catalysts. The special morphology assembled by the 0D carbons constituted the percolating clusters and promoted electron transport throughout the 1D carbons. The strategy and theory can be adapted to general electrocatalytic applications for achieving and interpreting precise tuning on highly efficient electron transfer in electrocatalysts.