Extra Generation Research Articles

Chromium toxicity induced oxidative damage in two rice cultivars and its mitigation through external supplementation of brassinosteroids and spermine.

The chromium (Cr) induced phytotoxicity avowed the scientific community to develop stress mitigation strategies to restrain the Cr accumulation inside the food chain. Whereas, brassinosteroids (BRs), and spermine (SPM) are well-known growth-promoting phytohormones, which enhance the plants health, and resilient the toxic effects under stress conditions. Until now, their interactive role against Cr-mitigation is poorly known. Hence, we conducted the hydroponic experiment to perceive the behavior of seed primed with BRs, or/and SPM treatment against Cr disclosure in two different rice cultivars (CY927; sensitive, YLY689; tolerant). Our findings delineated that BRs (0.01μM), or/and SPM (0.01mM) remarkably alleviated Cr-induced phytotoxicity by improving the seed germination ratio, chlorophyll pigments, PSII system, total soluble sugar, and minimizing the MDA contents level, ROS extra generation, and electrolyte leakage through restricting the Cr accretion in roots, and shoots of both rice cultivars under Cr stress. Additionally, the BRs, or/and SPM modulated the antioxidant enzyme, and non-enzyme activities to reduce the Cr-induced cellular oxidative damage as well as maintained the ionic hemostasis in both rice cultivars, especially in YLY689. Concisely, enhanced the plants biomass and growth. Overall, our outcomes revealed that BRs and SPM interact positively to alleviate the Cr-induced damages in rice seedlings on the above-mentioned indices, and combine treatment is much more efficient than solely. Moreover, the effect of BRs, or/and SPM was more obvious in YLY689 than CY927 to hamper the oxidative stress, and boost the antioxidant capacity.

Numerical evaluation of an optically switchable photovoltaic glazing system for passive daylighting control and energy-efficient building design

Adaptive control of solar heat gain and visible light transmission through windows is perceived to be a potential measure for enhancing energy conservation and visual comfort in buildings. In this study, a novel versatile window, named Building Integrated Photovoltaic (BIPV) smart window, was proposed to offer simultaneous improvement of daylighting control, on-site electricity generation and building energy efficiency, compared to traditional BIPV windows with static optical properties. The key components of the proposed system include an optically switchable thermotropic layer made of Hydroxypropyl Cellulose (HPC) hydrogel, crystalline-silicon photovoltaic cells, clear glass and low-emissivity (low-e) glass covers. The thermotropic layer can respond to heat by autonomously changing its visible and near-infrared optical properties, with which the amount of solar radiation into building spaces can be manipulated and thus the risks of excessive solar heating and illumination can be prevented. Apart from excellent solar modulation, the BIPV smart window can collect a proportion of the light scattered from the thermotropic layer and concentrate it onto the integrated PV cells for extra electricity generation. An innovative methodology has been proposed to predict the optical, thermal and electrical properties of the BIPV smart window under varying ambient conditions. Numerical simulations have been carried out in EnergyPlus to predict the window's performance when it is applied to an office-type environment in the climate of Nottingham, the UK. The influence of different window design scenarios, in terms of Window-to-Wall Ratio (WWR), orientation and transition temperature, has been investigated. It was found that using the BIPV smart window can achieve an annual energy saving of 36.6% but also a more comfortable indoor luminous environment, compared to the counterpart BIPV window (with no thermotropic layer integrated), when installed in the south-oriented office with a WWR of 25%.

Photoconductive Charge Transfer Complexes as Charge Transport Layers for High Performance Inverted Perovskite Solar Cells

AbstractCharge transport layers (CTLs) are critical for achieving high power conversion efficiency (PCE) and stability of perovskite solar cells (PSCs). Herein, the p‐type bulk heterojunction (p‐BHJ, i.e., PCBM doped PTAA) and n‐type BHJ (n‐BHJ, i.e., PBDTTT‐C‐T doped PCBM) charge transfer complexes are employed as hole and electron transport layers, respectively, to fabricate inverted PSCs. The photo‐induced charge transfer between p‐type and n‐type organic semiconductors in the BHJ layers provides extra photoconductivity for enhanced charge transport and quasi‐Fermi level splitting, hence enhancing the fill factor and open‐circuit voltage of PSCs. The p‐BHJ layer helps to improve the crystallinity and light absorption of perovskite, whilst the n‐BHJ layer provides extra light absorption and charge generation to boost the short‐circuit current. The combination of p‐BHJ and n‐BHJ CTLs in Cs0.05(FA0.92MA0.08)0.95Pb (I0.92Br0.08)3 based inverted PSCs synergistically enhances the PCE from 18.3% to 22.6% with superior operational and thermal stabilities, and showing a negligible dependence on the thickness of these BHJ CTLs. Density functional theory simulations show that the formation energy of BHJ complex is critical in determining the doping effect and the ultimate performance enhancement of PSCs.

Boosting the Extra Generation of Superoxide Radicals on Graphitic Carbon Nitride with Carbon Vacancies by the Modification of Pollutant Adsorption for High-Performance Photocatalytic Degradation

Boosting the Extra Generation of Superoxide Radicals on Graphitic Carbon Nitride with Carbon Vacancies by the Modification of Pollutant Adsorption for High-Performance Photocatalytic Degradation

PV-hosting-capacity enhancement and power-quality improvement through multiobjective reconfiguration of harmonic-polluted distribution systems

The current steps toward the implementation of carbon–neutral electrical energy systems lead to high levels of PV penetration especially in residential sectors. However, there are many limitations in the integration of extra PV generation units in modern distribution systems. Hence, supplementary actions are needed for providing the capability of hosting high levels of PV units in future grids. In this study, the application of Distribution System Reconfiguration (DSR) is examined in order to increase PV Hosting Capacity (PVHC) of a harmonically polluted distribution system. However, bringing several services together, DSR is studied in a multiobjective framework to improve the voltage profile and decrease the total energy loss as well as improving the PVHC. Moreover, probabilistic demand scenarios are included in this study through applying different combinations of linear and nonlinear load-levels to provide a more precise assessment of the objectives. Finally, a solution strategy is proposed for the presented multiobjective problem based on the implementation of the Non-dominated Sorting Genetic Algorithm II (NSGA-II) and fuzzy decision-making method. The proposed framework is then applied to modified 33-bus and 69-bus distribution systems in presence of nonlinear loads. According to the results, applying the proposed methodology for DSR could successfully increase the PVHC of the harmonic-polluted grid as well as providing voltage profile stabilization and a considerable decrease of the energy loss in the system.

The thrust enhancement for SDBD with nanostructured TiO2 films

Design requirements of the structural features, the material properties, and the processing capabilities are hard to be satisfied in nanotechnologies simultaneously. In this paper, TiO2 nanoparticles that are chemically reliable have been processed through the doctor blade method to realize a kind of field enhancement nanostructure, aiming to enhance the dielectric-barrier-discharge plasma actuation performance. It is found that the thrust enhancement rate could be approximately 72% at 13 kV and 8 kHz, compared to the controlled samples. In addition, a threshold phenomenon of the thrust enhancement effect was also found from the experiments, where the applied voltage and frequency lower than specific criteria could both lead to a decrease in the thrust generation and vice versa. It is suggested that the increase in the ionization frequency resulted from the field enhancement effect of the nanostructures is the leading mechanism for the extra thrust generation, which is inconsistent with the experimental examinations of the plasma characteristics and the plasma kinetic simulation. The results suggested that TiO2 nanoparticles could be used to improve the actuation performance in harsh environments with sound substrate compatibility.

TME-responded Full-biodegradable nanocatalyst for mitochondrial calcium Overload-induced hydroxyl radical bursting cancer treatment

Mitochondrial calcium ions (Ca2+) overload, an abnormal accumulation of free Ca2+ in mitochondrial, has become a potential strategy for effective cancer treatment. Inspired by mitochondrial Ca2+ overload-induced ROS generation, a tumor microenvironment (TME)-responded full-degradable ACC@Cu2O-TPP NCs are successfully fabricated for effective chemodynamic therapy (CDT) via toxic hydroxyl radical (∙OH) bursting. The as-synthesized nanocatalysts are stable and safe in normal tissues but will quickly degrade into Ca2+ and cuprous ions (Cu+) under the acidic TME. The mitochondrial Ca2+ overload effectively simulates extra H2O2 generation. Then Cu+ catalyzes the produced H2O2 into toxic ∙OH to kill the tumor cells via Fenton-like reaction. Meanwhile, abundant GSH in tumor cells can further reduce Cu2+ into Cu+ to enhance the CDT effect. Both in vitro and in vivo evaluations demonstrate the efficient anti-tumor effect of ACC@Cu2O-TPP NCs via mitochondrial Ca2+ overload-induced ∙OH bursting. We believe that the development of ACC@Cu2O-TPP NCs will be an amazing inspiration for designing safe and green chemodynamic nanocatalysts for highly efficient cancer treatment.

Seed priming with nitric oxide and/or spermine mitigate the chromium toxicity in rice (Oryza sativa) seedlings by improving the carbon-assimilation and minimising the oxidative damages.

Chromium (Cr) is a serious environmental contaminant that drastically limited the crop yields. Nitric oxide (NO) and spermine (Spm) portrayal significance in improving the plant tolerance against abiotic stresses. Therefore, we investigate the protective efficacy of seed priming with NO (100μM) and/or Spm (0.01mM) in minimising the Cr-induced toxic effects in rice (Oryza sativa L.) plants. Our outcomes revealed that Cr alone treatments (100μM) notably reduced the seed germination rate, plant growth, photosynthetic apparatus, nutrients uptake and antioxidant defence system, but extra generation of reactive oxygen species (ROS). Interestingly, the combine applications of NO and Spm significantly reversed the Cr-induced toxic effects by reducing the Cr-accumulation, maintaining the nutrient balance, improving the germination indices, levels of photosynthetic pigments (chl a by 24.6%, chl b by 36.3%, chl (a+b ) by 57.2% and carotenoids by 79.4%), PSII, photosynthesis gas exchange parameters and total soluble sugar (74.9%) by improving antioxidative enzyme activities. As a result, NO+Spm lowered the accumulation of oxidative markers (H2 O2 by 93.9/70.4%, O2 ˙- by 86.3/69.9% and MDA by 97.2/73.7% in leaves/roots), electrolyte leakage (71.4% in leaves) and improved the plant growth traits. Based on these findings, it can be concluded that NO triggers Spm to minimise the Cr-accumulation and its adverse effects on rice plants. Additionally, combined treatments (NO+Spm) were more effective in minimising the Cr-induced toxic effects in comparison to NO and Spm alone treatments. Thus, co-exposure of NO and Spm may be utilised to boost rice tolerance under Cr stress conditions.

Heat and Flow Control in Cavity with Cold Circular Cylinder Placed in Non-Newtonian Fluid by Performing Finite Element Simulations

A study on strategies regarding advancement in heat transfer characteristics in two-dimensional closed domains by placing cold cylinders is conducted. This effort is undertaken due to the fact that active and passive control in heat transmission is connected with provision of temperature differences at different locations of enclosures. Based on the experiments, researchers have concluded that placement of cold cylinder in non-uniformly distributed heat in a cavity is the most effective technique to enrich heat transfer rate, along with reducing the the waste of extra heat generation in processes such as polymer and aero dynamical extrusion, glass cooling, refrigeration, heating and cooling systems. Thus, the prime goal of this work is to outline heat and flow characteristics of non-linear fluid occupied in a square enclosure with adjustment of the cold cylinder. Heat transfer attributes are incorporated by accounting buoyancy forces and forming coupling of molecular diffusion of fluid within the flow domain. Formulation of the problem in dimensionless form is attained by encapsulating the aspects of natural convection in view of principal partial differential equations. Parametric study for governing expressions is computed numerically with the finite element method based on COMSOL Multiphysics version 5.6. Quadric interpolating functions are used to obtain information about velocity and temperature on nodes in elements. Hybrid meshing is manifested for discretization of the domain into rectangular and triangular elements. For the optimized variation in flow structures, prospective parameters are varied from 0.5≤n≤1.5, 5 ≤ Pr ≤ 35 and 102 ≤ Ra ≤106. The achieved results are projected graphically through streamlines, isotherms, and local and average Nusselt numbers. Tabular data for kinetic energy and wall heat flux are also calculated. It is inferred through the analysis that, with uplift in the Rayleigh number Ra elevation in the magnitude of kinetic energy and convective heat transfer arises, whereas the reverse pattern is depicted versus the power–law index n.

Economic Design of Hybrid Pico-Hydraulic/Photovoltaic Generation System: A Case Study in Egypt

Clean and renewable energy sources are the preferable power system generations for the overall world. This research aims to present a very highly integrated, economic, professional, and simple construction, clean and natural resources usage of the renewable hybrid generation system. This research performs analysis, systematic representation, evaluation, and design of the hybrid proposed system—pico-hydraulic from home usage water and photovoltaic (PV)—to generate an optimal renewable generation system using a new professional control system. Applying this proposed technique in Egypt shows that the hybrid system successfully overcame Egypt’s energy crisis. Renewable energy will rise to 8.782% by increasing 7.323% (14,408.83 GWh/Y). Besides, this system increases the power supply reliability; it gives an additional emergency supply and reduces the exhausts from other generation stations (e.g., CO2). The saving from this hybrid system is very effective for; the residential sector (subscribes), which will be ranged from 9599.298 million E£/10Ys up to 86,393.68 million E£/10Ys that equals 5399.6 million $, government to use this extra generation energy to reduce the maximum loads from various stations. A practical model has been presented with results to verify the high efficiency of the proposed system that illustrates the effective performance of the used hybrid system.

Enthalpy profile of pH-induced flocculation and redispersion of polyacrylic acid-coated nanoparticles in protic ionic liquid, N,N-diethylethanolammonium trifluoromethanesulfonate

Maghemite nanoparticles coated with polyacrylic acid (pAA) were dispersed in the protic ionic liquid, diethylethanolammonium trifluoromethanesulfonate (DEEAH+⋅TfO−), and the thermodynamics of particle dispersion was studied by means of potentiometric and calorimetric titrations over the entire accessible pH range. As previously reported, the domain of colloidal stability is divided into two pH regions, mildly acidic and basic, separated by a flocculation domain at an intermediate pH. In this study, solvent DEEAH+⋅TfO− was first characterized in terms of the thermodynamic parameters of two reference reactions: autoprotolysis and ionization of acetic acid. A negative autoprotolysis entropy is obtained due to hydrogen-bond formation between the neutralized solvent cation, DEEA, and the neighboring cation DEEAH+. This suggests that the solvent structure is reinforced by the formation of neutral species, being an opposite trend to both ethylammonium nitrate and water. Second, the ionization and flocculation of pAA-coated nanoparticles (CNps) in the ionic liquid were examined. The potentiometric results could be modeled using a simple pAA ionization, independent of the aggregation state over the entire pH range. However, the calorimetric titration detected extra heat generation in an acidic condition prior to flocculation, in addition to an ionization enthalpy of pAA of 30 kJ/mol. This exothermic contribution is attributed to a change in the solvation process of CNps in the ionic liquid. Herein, we propose a model in which different types of solvation in the acidic and basic domains are sufficient to ensure colloidal stability, while aggregation unfolds between the switching pH.

Pressurized chemical looping methane reforming to syngas for efficient methanol production: Experimental and process simulation study

This study investigates the potential of applying pressurized chemical looping reforming (CLR) mechanism for syngas to methanol production process combining of experimental demonstration of methane reforming to syngas and simulation for integration in methanol production. The experimental study was conducted using the internally circulating reactor (ICR) that was specially designed to enable pressurized CLR operation where several experimental cases were completed using a NiO-based oxygen carrier. Up to 4 kW of methane feed was reformed to syngas, achieving high conversion efficiencies and high syngas recovery and purity at pressurized conditions up to 4 bar. Co-feeding H2O or CO2 was found to affect mainly the H2/CO ratio. The simulation study evaluated the potential of integrating the CLR process for large scale methanol production through comprehensive thermodynamic analysis using Aspen plus. The results revealed that CLR-based methanol plant is a highly attractive pathway achieving higher methanol production efficiency outperforming the conventional autothermal reforming (ATR) -based plant by ∼5% efficiency. The main benefits of the CLR-based system is the avoidance of the air separation unit required for ATR plants, and the extra power generation through the gas turbine utilizing the hot exhaust gas of the air reactor. A detailed sensitivity study was also conducted to study the effects of the CLR operating pressure, and the reduced syngas purity caused by possible gas leakage in the ICR, on the overall methanol plant performance.

Equivalent circuit modelling of large hydropower plants with complex tailrace system for ultra-low frequency oscillation analysis

Focused on the hydraulic factor-induced ultra-low frequency oscillation phenomenon occurring in a large hydropower plant, this paper investigates the precise modelling of hydraulic transient characteristics in its complex tailrace system and reveals the feasible oscillation suppression schemes from the source side. Combining the telegraphist's equations with the Saint-Venant equations, the mathematical expression of equivalent circuit model (ECM) for open channels is deduced, thus to expand the utilization of ECM to hydraulic transients description in pressurized pipe and open channel combination systems and to establish the high-order equivalent circuit topology of the overall tailrace system in a real hydropower plant. Based on the mathematical model, the feasibility and effectiveness of two different oscillation suppression approaches involving increasing the hydraulic losses on the branch tailrace channels or the main tailrace channel, respectively, are discussed in detail via numerical simulation. Furthermore, the superiority of the oscillation suppression scheme involving increasing hydraulic losses in branch channels in reducing the extra power generation loss is demonstrated. The application of equivalent circuit theory in complex hydraulic systems can contribute to the mechanism-related research on ultra-low frequency oscillations in hydro-dominant power systems.

Six-Stroke Cylinder Engine : An Emerging Technology

The requirement for the advancement of internal combustion (IC) engines and enhance methods for the combustion cycle is increasing day by day. The four-stroke combustion engine is extensively used due to better fuel economy and less exhaust smoke. However, the major drawback includes a considerable amount of extra heat energy generation that directly adds up to waste energy. In order to overcome the limitation, the idea of computing two extra strokes in the four-stroke engine to utilize the waste energy has been introduced. The six-stroke engine has significantly improved the fuel working ratio per cycle. Incorporating alternative fuels like hydrogen and HHO into six-stroke technology increases efficiency and minimizes exhaust emissions. A six-stroke engine could be the solution for making hybrid automobile technology more convenient. The review article aims to thoroughly understand the underlying principles behind the improved efficiency of a six-stroke cylinder engine. The researches on the six-stroke cylinder engine are summarized in the literature review. The design configuration of alternative fuels is discussed towards the end of the paper.

Optimal equipment arrangement of a total site for cogeneration of thermal and electrical energy by using exergoeconomic approach

The optimal equipment arrangement for a system for cogeneration of thermal and electrical energy for a total site is determined with exergoeconomic analysis. A steam power plant can operate concurrently in a dual-use mode producing steam and electricity. It is important to know the potential for cogeneration before designing and optimizing a central utility system in order to establish on site fuel demand targets. In the current study, two case studies with different backpressure steam turbines arrangement are considered and, if extra power generation is needed, designs with a system of condensing and gas turbines are examined. The minimum exergy destruction rate, maximum exergy efficiency, minimum total capital cost rate and minimum exergy destruction cost rate for these arrangements are investigated with exergoeconomic analysis. Finally, selected backpressure steam turbines arrangement in conjunction with the gas turbine system are introduced for finding the optimum arrangement of the cogeneration system in the total site with an exergoeconomic approach.

State-Aware Stochastic Optimal Power Flow

The increase in distributed generation (DG) and variable load mandates system operators to perform decision-making considering uncertainties. This paper introduces a novel state-aware stochastic optimal power flow (SA-SOPF) problem formulation. The proposed SA-SOPF has objective to find a day-ahead base-solution that minimizes the generation cost and expectation of deviations in generation and node voltage set-points during real-time operation. We formulate SA-SOPF for a given affine policy and employ Gaussian process learning to obtain a distributionally robust (DR) affine policy for generation and voltage set-point change in real-time. In simulations, the GP-based affine policy has shown distributional robustness over three different uncertainty distributions for IEEE 14-bus system. The results also depict that the proposed SA-OPF formulation can reduce the expectation in voltage and generation deviation more than 60% in real-time operation with an additional day-ahead scheduling cost of 4.68% only for 14-bus system. For, in a 30-bus system, the reduction in generation and voltage deviation, the expectation is achieved to be greater than 90% for 1.195% extra generation cost. These results are strong indicators of possibility of achieving the day-ahead solution which lead to lower real-time deviation with minimal cost increase.

Optimizing operational costs and PV production at utility scale: An optical fiber network analogy for solar park clustering

Increasing the share of renewable energy sources in power systems is key to a successful energy transition. Optimal renewable site selection requires a holistic approach, involving land, resources, environmental and economical data and constraints. In this paper we consider the problem of solar PV penetration into the power network as a spatiotemporal analysis combined with decision support targeted for policy makers and investors. Our goal is to seek new models that maximize energy penetration and stability into the network, while minimizing the operational costs. We show how the selection of solar PV sites can be accomplished to satisfy such objectives by investigating the optimal clustering of multiple solar PV parks around a shared electrical substation. This is a combinatorial problem in terms of all the potential clusters given the set of PV site candidates. Our main contribution lies in identifying and proposing a modeling analogy of our problem with the so-called SONET problem, tackled in fiber network designs. We show how this new spatiotemporal PV park placement model minimizes operational costs, while increasing energy stability of the solutions produced. We also introduce a GIS preprocessing step to reduce the computational cost of the proposed approach. We compare our proposed SONET-based model to an existing GIS-optimization model on a real case study and data from the French Guiana’s power system. This new approach aggregates multiple PV parks into clusters distributed across the territory. In the case of French Guiana, the same global nominal power (≈45MW) can, for instance, be distributed among 11 PV parks and 3 clusters, against 3 large-scale PV parks. Results show substantial gain in costs per kWh produced, up to 10MW of extra installed power and 16GWh of extra power generation when considering PV parks ⩽5MW. The new cluster configuration also ensures improved energy stability of the solutions, resulting in mitigation of the risks for both the network manager and the decision maker.

Bi3+ occupancy rearrangement in K2-xAxMgGeO4 phosphor to achieve ultra-broad-band white emission based on alkali metal substitution engineering

Ultra-broad-band white emitting phosphors have a wide application prospect in the new generation of illumination systems. Due to the sensitivity of Bi3+ to the surrounding environment, it exhibits different luminescence properties in different crystallographic sites, which makes it easy to achieve white emission. Cationic substitution engineering is the most effective strategy for controlling the environment around Bi-site and realizing the spectrum tuning. Herein, we conducted substitution engineering in K2MgGeO4:Bi3+ (KMGO:Bi3+) that uses alkali metal A+ (A = Li, Na, Rb) to substitute K+. The difference in emission spectrum excited at various wavelengths is related to extra luminescent centers generation and Bi3+ occupancy rearrangement in KMGO:Bi3+ under the influence of Li+ and Na+, which also leads to the expansion of full widths at half-maximum (FWHM) to 204 nm forming a bright white emission. Besides, the modulation of Rb+ increases the activation energy and enhances its thermal stability to 88.66%. The high Ra values (93.4) of the fabricated WLED indicate that K1.456Na0.54MgGeO4:0.004Bi3+ could be used as a single-component white phosphor in solid-state lighting. Our research shows that alkali metal substitution engineering is of great significance to controlling the luminescence emission and improving the thermal stability of luminescent materials.

High-Fidelity Simulations of a High-Pressure Turbine Vane Subject to Large Disturbances: Effect of Exit Mach Number on Losses

Abstract We report on a series of highly resolved large-eddy simulations of the LS89 high-pressure turbine (HPT) vane, varying the exit Mach number between Ma = 0.7 and 1.1. In order to accurately resolve the blade boundary layers and enforce pitchwise periodicity, we for the first time use an overset mesh method, which consists of an O-type grid around the blade overlapping with a background H-type grid. The simulations were conducted either with a synthetic inlet turbulence condition or including upstream bars. A quantitative comparison shows that the computationally more efficient synthetic method is able to reproduce the turbulence characteristics of the upstream bars. We further perform a detailed analysis of the flow fields, showing that the varying exit Mach number significantly changes the turbine efficiency by affecting the suction-side transition, blade boundary layer profiles, and wake mixing. In particular, the Ma = 1.1 case includes a strong shock that interacts with the trailing edge, causing an increased complexity of the flow field. We use our recently developed entropy loss analysis (Zhao and Sandberg, 2019, “Using a New Entropy Loss Analysis to Assess the Accuracy of RANS Predictions of an HPT Vane,” ASME Turbo Expo 2019: Turbomachinery Technical Conference and Exposition, Paper No. GT2019-90126) to decompose the overall loss into different source terms and identify the regions that dominate the loss generation. Comparing the different Ma cases, we conclude that the main mechanism for the extra loss generation in the Ma = 1.1 case is the shock-related strong pressure gradient interacting with the turbulent boundary layer and the wake, resulting in significant turbulence production and extensive viscous dissipation.

Comprehensive assessment and multi-objective optimization of a green concept based on a combination of hydrogen and compressed air energy storage (CAES) systems

In this paper, a novel efficient and environmentally-friendly hybrid energy production/storage system comprising a compressed air energy storage, a heliostat-driven Brayton cycle, and a hydrogen production unit is proposed and thoroughly investigated. The aim is to minimize the pollutant emission of compressed air energy storage technology while adequately addressing intermittency and electricity curtailment of power grids with high penetration of renewable sources. The proposed system uses the surplus power and wasted heat of the solar-powered Brayton cycle to store pressurized air and hydrogen during off-peak periods, and releases them for extra power generation during peak demand periods. For the performance analysis of this hybrid solution, the reference system is precisely analyzed from thermodynamic and economic points of view. Then, training the results of the developed model employing an artificial neural network, four multi-objective optimization programs based on MOPSO, NSGA-II, PESA-II, and SPEA2 algorithms are performed to find an optimal trade-off between thermodynamic performance and economic attractiveness of the system. It is concluded that the system has an exergy round trip efficiency of 60.4% and a total cost rate of 117.5 $/GJ at the optimum solution. Applying the proposed method for the case study of Los Angeles with real historical data, 3313 ton/year Carbone-Dioxide emission is prevented, resulting in around 80,000 $/year environmental cost reduction. Also, the economic analysis indicates a payback period of shorter than 4.6 years for the system.