Showing papers in "International Journal of Energy Research in 2017"

Degradation mechanisms in Li-ion batteries: a state-of-the-art review

Abstract: Summary One of the most prominent energy storage technologies which are under continuous development, especially for mobile applications, is the Li-ion batteries due to their superior gravimetric and volumetric energy density. However, limited cycle life of Li-ion batteries inhibits their extended use in stationary energy storage applications. To enable wider market penetration of Li-ion batteries, detailed understanding of the degradation mechanisms is required. A typical Li-ion battery comprised of an active material, binder, separator, current collector, and electrolyte, and the interaction between these components plays a critical role in successful operation of such batteries. Degradation of Li-ion batteries can have both chemical and mechanical origins and manifests itself by capacity loss, power fading or both. Mechanical degradation mechanisms are associated with the volume changes and stress generated during repetitive intercalation of Li ions into the active material, whereas chemical degradation mechanisms are associated with the parasitic side reactions such as solid electrolyte interphase formation, electrolyte decomposition/reduction and active material dissolution. In this study, the main degradation mechanisms in Li-ion batteries are reviewed. Copyright © 2017 John Wiley & Sons, Ltd.

Battery state of health estimation: a structured review of models, methods and commercial devices

Abstract: Summary Estimating the dynamic status parameters of a battery, such as its state of health (SoH) and remaining useful life (RUL), is still a very difficult and complex task. In this paper we perform a structured review of the most relevant state of the art models, algorithms and commercial devices employed in the estimation of the SoH/RUL battery performance figures, in the context of embedded applications. The models and estimation techniques are thoroughly classified and, for each taxonomy class, a presentation of the working principles is made. A comprehensive set of metrics is then introduced for the evaluation of the SoH/RUL estimation techniques from the perspective of their implementation and operation efficiency in embedded systems. These algorithms are then analyzed and discussed in a comparative manner, with concrete figures and results. The capability and the performance of the different types of off-the-shelf fuel gauges to estimate the battery SoH/RUL parameters are also evaluated in this paper. Copyright © 2016 John Wiley & Sons, Ltd.

Liquid cooling based on thermal silica plate for battery thermal management system

Abstract: Summary To achieve safe, long lifetime, and high-performance lithium-ion batteries, a battery thermal management system (BTMS) is indispensable. This is especially required for enabling fast charging-discharging and in aggressive operating conditions. In this research, a new type of battery cooling system based on thermal silica plates has been designed for prismatic lithium-ion batteries. Experimental and simulations are combined to investigate the cooling capability of the BTMS associated to different number of cooling channels, flow rates, and flow directions while at different discharge C-rates. Results show that the maximum temperature reached within the battery decreases as the amount of thermal silica plates and liquid channels increases. The flow direction had no significant influence on the cooling capability. While the performance obviously improves with the increase in inlet flow rate, after a certain threshold, the gain reduces strongly so that it does not anymore justify the higher energy cost. Discharged at 3 C-rate, an inlet flow rate of 0.1 m/s was sufficient to efficiently cool down the system; discharged at 5 C-rate, the optimum inlet flow rate was 0.25 m/s. Simulations could accurately reproduce experimental results, allowing for an efficient design of the liquid-cooled BTMS.

Cycling degradation testing and analysis of a LiFePO4 battery at actual conditions

Abstract: Summary This paper presents a degradation testing of a lithium-ion battery developed using real world drive cycles obtained from an electric vehicle (EV). For this, a data logger was installed in the EV, and real world drive cycle data were collected. The EV battery system consists of 3 lithium-ion battery packs with a total of 20 battery modules in series. Each module contains 6 series by 49 parallel lithium-ion cells. The vehicle was driven in the province of Ontario, Canada, and several drive cycles were recorded over a 3-month period. However, only 4 drive cycles with statistical analysis are reported in this paper. The reported drive cycles consist of different modes: acceleration, constant speed, and deceleration in both highway and city driving at −6°C, 2°C, 10°C, and 23°C ambient temperatures with all accessories on. Additionally, individual cell characterization was conducted using a C/25 (0.8A) charge-discharge cycle and hybrid pulse power characterization (HPPC). The Thevenin battery model was constructed in MATLAB along with an empirical degradation model and validated in terms of voltage and SOC for all drive cycles reported. The presented model closely estimated the profiles observed in the experimental data. Data collected from the drive cycles showed that a 4.6% capacity fade occurred over the 3 months of driving. The empirical degradation model was fitted to these data, and an extrapolation estimated that 20% capacity fade would occur after 900 daily drive cycles.

Recent advances in photo‐anode for dye‐sensitized solar cells: a review

Abstract: Summary Dye-sensitized solar cell (DSSC) attracts immense interest in the last few decades due to its various attractive features such as low production cost, ease of fabrication and relatively high conversion efficiency, which make it a strong competitor to the conventional silicon-based solar cell. In DSSC, photo-anode performs two important functions, viz. governs the collection and transportation of photo-excited electrons from dye to external circuit as well as acts as a scaffold layer for dye adsorption. The photo-anode usually consists of wide band gap semiconducting metal oxides such as titanium dioxide (TiO2) and zinc oxide (ZnO) deposited on the transparent conducting oxide substrates. The morphology and composition of the semiconductor oxides have significant impact on the DSSC photovoltaic performance. Therefore, enormous research efforts have been undertaken to investigate the influences of photo-anode modifications on DSSC performance. The modifications can be classified into three categories, namely interfacial modification through the introduction of blocking and scattering layer, doping with non-metallic anions and metallic cations and replacing the conventional mesoporous semiconducting metal oxide films with one-dimensional or two-dimensional nanostructures. In the present review, the previously mentioned modifications on photo-anode are summarized based on the recent findings, with particular emphasis given to published works for the past 5 years. Copyright © 2017 John Wiley & Sons, Ltd.

A review on sediment microbial fuel cells as a new source of sustainable energy and heavy metal remediation: mechanisms and future prospective

Abstract: Summary Sediment microbial fuel cells (SMFCs) are different from microbial fuel cells because they are completely anoxic and lack a membrane. SMFCs are a novel technology for the simultaneous production of renewable energy and bioremediation of heavy metals. Recently, SMFCs have attracted the attention of many researchers because of their moderate functioning parameters and ability to use a range of biodegradable substrates like glucose, glutamic acid, river water, cysteine, acetate, and starch. The inocula used in SMFCs include river sediment, marine sediment, and wastewater. For power generation, many exoelectrogens in SMFCs have the ability to transfer electrons from electrodes by using natural electron shuttles. Exoelectrogens use four primary pathways to transfer electrons to the electrodes, including short-range electron transfer through redox-active proteins, soluble electron shuttling molecules, long-range electron transport by conductive pili, and direct interspecies electron transfer. The most dominant mechanism is long-range electron transfer via conductive pili because pili have metal-like conductivity. The powering by microbes is an emerging technique for the remediation of heavy metals from sediments. The pathways for transferring electrons in electrotrophs operate in the opposite direction from those in exoelectrogens. To further upgrade SMFC technology, this review targets the prototype, operating factors, working mechanisms, applications, and future perspectives of SMFCs. Copyright © 2017 John Wiley & Sons, Ltd.

Influence of overlap ratio and aspect ratio on the performance of Savonius hydrokinetic turbine

Abstract: Summary A strong contender for the utilization of the hydropower sources is Savonius turbine because of its good starting characteristics and simplicity in fabrication. The aim of the present work is to study the effect of overlap ratio and aspect ratio on the performance of a Savonius turbine for hydrodynamic application. The findings would be useful to decide design parameters of a Savonius hydrokinetic turbine. This study is conducted in three open channels namely small laboratory channel with depth of water 270 mm, large laboratory channel with depth of water 480 mm and a real life irrigation canal with depth of water 900 mm. Influence of endplates is studied to establish the significance of their presence on rotor performance. Maximum coefficient of power is observed for an overlap ratio of around 0.11 for Savonius turbines with aspect ratio less than 0.6. For a given overlap ratio, the increasing trend of the coefficient of power is observed with the increase in the aspect ratio. However, for aspect ratios greater than 1.8, the coefficient of power becomes nearly stagnant. Copyright © 2016 John Wiley & Sons, Ltd.

Performance of large-scale biomass gasifiers in a biorefinery, a state-of-the-art reference

Abstract: The Gothenburg Biomass Gasification plant (2015) is currently the largest plant in the world producing biomethane (20 MWbiomethane) from woody biomass We present the experimental data from the first measurement campaign and evaluate the mass and energy balances of the gasification sections at the plant Measures improving the efficiency including the use of additives (potassium and sulfur), high-temperature pre-heating of the inlet streams, improved insulation of the reactors, drying of the biomass and introduction of electricity as a heat source (power-to-gas) are investigated with simulations The cold gas efficiency was calculated in 717%LHVdaf using dried biomass (8% moist) The gasifier reaches high fuel conversion, with char gasification of 54%, and the fraction of the volatiles is converted to methane of 34%mass Because of the design, the heat losses are significant (52%LHVdaf), which affect the efficiency The combination of potential improvements can increase the cold gas efficiency to 835%LHVdaf, which is technically feasible in a commercial plant The experience gained from the Gothenburg Biomass Gasification plant reveals the strong potential biomass gasification at large scale

Realistic simulation of fuel economy and life cycle metrics for hydrogen fuel cell vehicles

Abstract: Summary The present work contributes an engineered life cycle assessment (LCA) of hydrogen fuel cell passenger vehicles based on a real-world driving cycle for semi-urban driving conditions. A new customized LCA tool is developed for the comparison of conventional gasoline and hydrogen fuel cell vehicles (FCVs), which utilizes a dynamic vehicle simulation approach to calculate realistic, fundamental science based fuel economy data from actual drive cycles, vehicle specifications, road grade, engine performance, fuel cell degradation effects, and regenerative braking. The total greenhouse gas (GHG) emission and life cycle cost of the vehicles are compared for the case of hydrogen production by electrolysis in British Columbia, Canada. A 72% reduction in total GHG emission is obtained for switching from gasoline vehicles to FCVs. While fuel cell performance degradation causes 7% and 3% increases in lifetime fuel consumption and GHG emission, respectively, regenerative braking improves the fuel economy by 23% and reduces the total GHG emission by 10%. The cost assessment results indicate that the current FCV technology is approximately $2,100 more costly than the equivalent gasoline vehicle based on the total lifetime cost including purchase and fuel cost. However, prospective enhancements in fuel cell durability could potentially reduce the FCV lifetime cost below that of gasoline vehicles. Overall, the present results indicate that fuel cell vehicles are becoming both technologically and economically viable compared with incumbent vehicles, and provide a realistic option for deep reductions in emissions from transportation. Copyright © 2016 John Wiley & Sons, Ltd.

A comprehensive review on energy management strategies of hybrid energy storage system for electric vehicles

Abstract: Summary The attention on green and clean technology innovations is highly demanded of a modern era. Transportation has seen a high rate of growth in today's cities. The conventional internal combustion engine-operated vehicle liberates gasses like carbon dioxide, carbon monoxide, nitrogen oxides, hydrocarbons, and water, which result in the increased surface temperature of the earth. One of the optimum solutions to overcome fossil fuel degrading and global warming is electric vehicle. The challenging aspect in electric vehicle is its energy storage system. Many of the researchers mainly concentrate on the field of storage device cost reduction, its age increment, and energy densities' improvement. This paper explores an overview of an electric propulsion system composed of energy storage devices, power electronic converters, and electronic control unit. The battery with high-energy density and ultracapacitor with high-power density combination paves a way to overcome the challenges in energy storage system. This study aims at highlighting the various hybrid energy storage system configurations such as parallel passive, active, battery–UC, and UC–battery topologies. Finally, energy management control strategies, which are categorized in global optimization, are reviewed. Copyright © 2017 John Wiley & Sons, Ltd.

Wells turbine for wave energy conversion: a review

Abstract: In the past twenty years, the use of wave energy systems has significantly increased, generally depending on the oscillating water column (OWC) concept. Wells turbine is one of the most efficient OWC technologies. This article provides an updated and a comprehensive account of the state of the art research on Wells turbine. Hence, it draws a roadmap for the contemporary challenges which may hinder future reliance on such systems in the renewable energy sector. In particular, the article is concerned with the research directions and methodologies which aim at enhancing the performance and efficiency of Wells turbine. The article also provides a thorough discussion of the use of computational fluid dynamics (CFD) for performance modeling and design optimization of Wells turbine. It is found that a numerical model using the CFD code can be employed successfully to calculate the performance characteristics of W-T as well as other experimental and analytical methods. The increase of research papers about CFD, especially in the last five years, indicates that there is a trend that considerably depends on the CFD method.

Upgrading techniques for transformation of biogas to bio‐CNG: a review

Abstract: Summary Increasing consumption of fossil fuels and environmental concern has led to increased use of compressed natural gas (CNG) in the transportation sector. Keeping in view limited resources of CNG, biogas is advised as potential fuel to provide continuous supply of CNG in the form of bio-CNG. Various technologies, that is, physical and chemical absorption (using water and amine solutions, respectively, for the absorption of carbon dioxide), pressure swing adsorption, membrane separation, and cryogenic separation, are available for purifying biogas and thus upgrading it, to bio-CNG with about 95% methane. Among these, water scrubbing and pressure swing adsorption are the best technologies with respect to various aspects including cost; however, suitability of a technology is decided by various factors including size/quantity of biogas generation, targeted quality of biogas, site of application, and economics of process. Copyright © 2017 John Wiley & Sons, Ltd.

Review on the research of failure modes and mechanism for lead–acid batteries

Abstract: Summary The lead–acid battery (LAB) has been one of the main secondary electrochemical power sources with wide application in various fields (transport vehicles, telecommunications, information technologies, etc.). It has won a dominating position in energy storage and load-leveling applications. However, the failure of LAB becomes the key barrier for its further development and application. Therefore, understanding the failure modes and mechanism of LAB is of great significance. The failure modes of LAB mainly include two aspects: failure of the positive electrode and negative electrode. The degradations of active material and grid corrosion are the two major failure modes for positive electrode, while the irreversible sulfation is the most common failure mode for the negative electrode. Introduction of carbon materials to the negative electrodes of LAB could suppress sulfation problem and enhance the battery performance efficiently. This paper will attempt here to pull together observations made by previous research to obtain a more comprehensive and integrative view of LAB failure modes. Moreover, according to a detail investigation to the battery market, we have drawn an objective and optimistic conclusion of LAB prospect. Copyright © 2016 John Wiley & Sons, Ltd.

Oxy-fuel combustion technology: current status, applications, and trends

Abstract: Summary The increased level of emissions of carbon dioxide into the atmosphere due to burning of fossil fuels represents one of the main barriers toward the reduction of greenhouse gases and the control of global warming. In the last decades, the use of renewable and clean sources of energies such as solar and wind energies has been increased extensively. However, due to the tremendously increasing world energy demand, fossil fuels would continue in use for decades which necessitates the integration of carbon capture technologies (CCTs) in power plants. These technologies include oxycombustion, pre-combustion, and post-combustion carbon capture. Oxycombustion technology is one of the most promising carbon capture technologies as it can be applied with slight modifications to existing power plants or to new power plants. In this technology, fuel is burned using an oxidizer mixture of pure oxygen plus recycled exhaust gases (consists mainly of CO2). The oxycombustion process results in highly CO2-concentrated exhaust gases, which facilitates the capture process of CO2 after H2O condensation. The captured CO2 can be used for industrial applications or can be sequestrated. The current work reviews the current status of oxycombustion technology and its applications in existing conventional combustion systems (including gas turbines and boilers) and novel oxygen transport reactors (OTRs). The review starts with an introduction to the available CCTs with emphasis on their different applications and limitations of use, followed by a review on oxycombustion applications in different combustion systems utilizing gaseous, liquid, and coal fuels. The current status and technology readiness level of oxycombustion technology is discussed. The novel application of oxycombustion technology in OTRs is analyzed in some details. The analyses of OTRs include oxygen permeation technique, fabrication of oxygen transport membranes (OTMs), calculation of oxygen permeation flux, and coupling between oxygen separation and oxycombustion of fuel within the same unit called OTR. The oxycombustion process inside OTR is analyzed considering coal and gaseous fuels. The future trends of oxycombustion technology are itemized and discussed in details in the present study including: (i) ITMs for syngas production; (ii) combustion utilizing liquid fuels in OTRs; (iii) oxy-combustion integrated power plants and (iv) third generation technologies for CO2 capture. Techno-economic analysis of oxycombustion integrated systems is also discussed trying to assess the future prospects of this technology. Copyright © 2017 John Wiley & Sons, Ltd.

A comprehensive review on theoretical framework‐based electric vehicle consumer adoption research

Abstract: Summary Green vehicles, such as electric vehicles (EVs), are getting noteworthy popularity among consumers worldwide. The purpose of this paper is to establish EVs as a feasible long-term solution for the future of technology in the vehicle industry, which can decrease the current dependency on fossil fuels and also decrease greenhouse gas (GHG) emissions. As a part of long-term benefits, the adoption of EVs gives environmentally friendly innovation to society. Despite positive environmental implications, the total number of EVs in usage is still inadequate. One of the major causes of this insubstantial adoption of EVs is largely dependent on the perceptions of consumers regarding EVs. However, this particular research study offers an inclusive outline on the existing hurdles for consumer adoption of EVs as well as a framework of the theoretical standpoints that were developed for the adoption behaviour, in addition to considering consumer intentions in the direction of EVs. In this particular study, the researcher found that the literature regarding EV adoption tried to address only the diffusion method of EVs. Whereas this study highlights consumer innovations, which provides a wide insight on consumer emotions to overlook the major aspect in consumer EVs' adoption research. The theme of this particular literature can be implemented in order to better understand the consumers' emotions and behaviour towards the adoption of EVs. The scholars further stated that there is a possible cause for more recent developments within the technological adoption part that can assist to be a standard for upcoming developments. For the last few years, knowledge regarding the problems surrounding the adoption and diffusion of EVs has gained less attention. This study expands this line of research by focusing on making a chance for developing the theoretical frameworks in terms of adding emotions in a psychological perspective where consumer behaviour and ethics are considered. Copyright © 2016 John Wiley & Sons, Ltd.

Enhancement in the photostability of natural dyes for dye-sensitized solar cell (DSSC) applications: a review

Abstract: Summary The advancements in the generation of solar cells have created a landmark to design a cost-effective, less weight, biocompatible, and environmental-friendly solar cell. Dye-sensitized solar cells (DSSCs) have become a topic of significant research in the recent years because of their imperative role in the zone of harvesting energy from the renewable source, and it appears to be a promising candidate for the triumph because of its low cost and ease of preparation. The use of synthetic dyes as a sensitizer for DSSC provides better efficiency and high durability. Unfortunately, they suffer from several margins such as higher cost and usage of toxic materials. These downsides have opened up for alternative sensitizer such as biocompatible natural dyes. Natural dyes contain plant pigments such as carotenoid, flavonoid, betalains, and chlorophyll that act as sensitizers (dye) for DSSC. But, the efficiency of natural dyes is not up to the mark mainly due to photoinstability of natural dye in the presence of sunlight that leads to photodegradation. The stability issues are mainly due to interaction of natural dyes with photoelectrode. The photoelectrodes in DSSC are semiconductor materials with superior characteristic of photocatalytic activity (PCA). The PCA of titanium dioxide (TiO2) generates high energetic free electrons on the surface of film that produce free radical ions in contact with moisture. These free radical ions readily degrade the organic matter present nearby (natural dye in DSSC). Thus, the PCA of photoelectrode is responsible for the photodegradation of dyes causing photoinstability. The main objective of this review is to study the photoinstability of natural dyes in DSSC. In this regard, the DSSC is concentrated into sections, and the stability issues due to PCA of photoelectrode are studied individually in the view of considering the DSSC operating with iodide-based electrolytes and platinum as counter electrode only. Various algae groups are featured as a study tool to overview the dye interaction with photoelectrode. It highlights the application of Z-scheme of photosynthesis to DSSC to have a broader perception on the working of DSSC and also shows some of the ways for improving the stability of dyes by suppressing or reducing the PCA of photoelectrode. Copyright © 2017 John Wiley & Sons, Ltd.

Recent development and challenges of multifunctional structural supercapacitors for automotive industries

Abstract: Summary In the last decades, fuel scarcity and increasing pollution level pave the way for an extensive interest in alternatives to petroleum-based fuels such as biodiesel, solar cells, lithium ion batteries, and supercapacitors. Among them, structural supercapacitors have been considered as promising candidates for automotive industries in present time. Herein, the use of carbon fiber-based supercapacitors in automotive applications is reviewed. Carbon fiber is an excellent candidate for vehicle body applications, and its composites could be widely used in the development of supercapacitors that could provide both structural and energy storage functions. Different surface modification processes of the carbon fiber electrode to enhance the electrochemical as well as mechanical performances are discussed. The advantages of the glass fiber separator and its comparison with other types of dielectric media have been incorporated. The synthesis procedures of the multifunctional solid polymer electrolyte and its significance have been also elaborated. The fabrication process, component selection, limitations, and future challenges of these supercapacitors are briefly assimilated in this review. Copyright © 2017 John Wiley & Sons, Ltd.

Microalgae as a potential source for biodiesel production: techniques, methods, and other challenges

Abstract: Summary This paper reviews some of the most important aspects of microalgae as a potential source for biodiesel production. Microalgae are photosynthetic microorganisms that can grow rapidly in a variety of environments because of their unicellular or multicellular structure depending on the species. They have the advantage of self-reproduction using solar energy and converting it into chemical energy via photosynthesis. This process concludes a full cycle in a few days, obtaining higher lipid yields than terrestrial crops. This review shows several techniques and some methodologies used in the biodiesel production process from microalgae as well as the challenges that must be overcome for large-scale process and in bio-refineries. Copyright © 2016 John Wiley & Sons, Ltd.

Progress on upgrading methods of bio-oil: A review

Abstract: Summary Bio-oil is a promising alternative energy source to crude oil for broad application prospects. Bio-oil can help us avoid over-reliance on petroleum resources and significantly reduce pollutants and greenhouse gas emissions, improve environment conditions, and protect ecological systems. However, bio-oil applications have been impeded because of limited technologies, and poor bio-oil quality has posed a great challenge. As such, considerable research efforts have been made for realizing its potential application value. Scientific and technical advancements on methods of bio-oil quality improvement to date are reviewed, with an emphasis on advantages and disadvantages of each method. It also points out barriers and gives some recommendations to enhance bio-oil combustion performance in the future. Copyright © 2017 John Wiley & Sons, Ltd.

An overview of the environmental, economic, and material developments of the solar and wind sources coupled with the energy storage systems

Abstract: Summary There is a constant growth in energy consumption and consequently energy generation around the world. During the recent decades, renewable energy sources took heed of scientists and policy makers as a remedy for substituting traditional sources. Wind and photovoltaic (PV) are the least reliable sources because of their dependence on wind speed and irradiance and therefore their intermittent nature. Energy storage systems are usually coupled with these sources to increase the reliability of the hybrid system. Environmental effects are one of the biggest concerns associated with the renewable energy sources. This study summarizes the last and most important environmental and economic analysis of a grid-connected hybrid network consisting of wind turbine, PV panels, and energy storage systems. Focusing on environmental aspects, this paper reviews land efficiency, shaded analysis of wind turbines and PV panels, greenhouse gas emission, wastes of wind turbine and PV panels' components, fossil fuel consumption, wildlife, sensitive ecosystems, health benefits, and so on. A cost analysis of the energy generated by a hybrid system has been discussed. Furthermore, this study reviews the latest technologies for materials that have been used for solar PV manufacturing. This paper can help to make a right decision considering all aspects of installing a hybrid system. Copyright © 2017 John Wiley & Sons, Ltd.

A review on conversion techniques of liquid fuel from waste plastic materials

Abstract: Summary The utilization of plastics has increased in packing sectors consistently, which lead indirectly to increased volumes of plastic wastes posing an environmental threat. Several utilization and recycling techniques of waste plastics are being practiced commercially around the world. In this article, recent conversion techniques of fuel oil from waste plastics and its utilization on a compression-ignition engine are discussed. Recent statistics says most of the plastic wastes are generated from packing industries that contains polyethylene, polypropylene. In this connection, conversion techniques of polyethylene and polypropylene practiced frequently by researchers include catalytic processing, thermal degradation, and co-processing. The effect of various parameters like catalysts, reaction temperature, and reaction time of the aforementioned conversion techniques are discussed in this review. Also, few research works about the utilization of waste plastic oil with a compression-ignition engine along with engine performance and emissions in various blends of diesel with plastic oil are highlighted here. Copyright © 2017 John Wiley & Sons, Ltd.

Robust microencapsulated phase change materials in concrete mixes for sustainable buildings

Abstract: Summary For passive building applications, phase change materials (PCMs) are microencapsulated to avoid leakage of PCM from concrete structure. The primary challenge of using microencapsulated PCM (MPCM) is its weak shell structure. New MPCMs with different shell compositions to prevent breakage during mixing in fresh concrete are needed. In this study, free radical polymerization method to microencapsulate capric acid–myristic acid mixture as PCM with two different methyl methacrylate co-polymers is proposed to produce robust MPCMs for building applications. Two new microcapsules (MPCM-1 and MPCM-2) having latent heats of 91.9 and 97.3 J/g were synthesized. SEM analyses showed the size of microcapsules being in the range of 400–850 nm for MPCM-1 and 250–475 nm for MPCM-2. Analyses also reveal that the shells of MPCMs were not harmed, as they were added into concrete mixes. The microsphere's geometry was preserved, and distribution was homogeneous. The MPCMs were also studied under thermal tests of 1000 heating/cooling cycles. No significant changes in thermal properties were observed after thermal cycling tests. Copyright © 2016 John Wiley & Sons, Ltd.

Thermodynamic analysis of a novel energy storage system based on compressed CO2 fluid

Abstract: Summary Because of rapidly growing renewable power capacity, energy storage system is in urgent need to cope with the reliability and stability challenges. CO2 has already been selected as the working fluid, including thermo-electrical energy storage or electrothermal energy storage systems and compressed CO2 energy storage (CCES) systems. In this paper, a CCES system based on Brayton cycle with hot water as the heat storage medium is proposed and analyzed. Thermodynamic model of the system is established for energy and exergy analysis. Sensitivity analysis is then conducted to reveal effects of different parameters on system performances and pursue optimization potential. At a typical transcritical operation condition, round trip efficiency is 60% with energy density of 2.6 kWh/m3. And for the typical supercritical operation condition, the round trip efficiency can reach 71% with energy density of 23 kWh/m3. High round trip efficiency and energy density, which is comparable with those of compressed air energy storage systems, thermo-electrical energy storage (electrothermal energy storage) systems, and other CCES systems, lead to promising prospect of the proposed system. Copyright © 2017 John Wiley & Sons, Ltd.

Design of robust battery capacity model for electric vehicle by incorporation of uncertainties

Abstract: Summary The improvement in the operating range of electric vehicles can be accomplished by robust modelling of the design and optimization of the energy storage capacity of the battery pack system. In this work, the authors have conducted a comprehensive survey on battery modelling methods and identified critical areas of improvement vital for estimating the battery capacity. This work proposes the artificial intelligence approach of automated neural networks search (ANS) in development of the robust battery capacity models for the lithium ion batteries based on the inputs (temperature and discharge rates). The robustness in the models is introduced by incorporating uncertainties in the inputs (the temperature and discharge rates, the architecture of algorithm and the models). The statistical analysis and validation of the models reveal that the models formulated using an ANS approach outperform the response surface regression models with correlation coefficient achieved as high as 0.97. The uncertainty analysis based on normal distribution of the inputs suggests that the models formulated from ANS are least sensitive to change in the input conditions when compared to response surface regression models. The global sensitivity analysis reveals that the temperature is a dominant factor for accurate battery capacity estimation. Copyright © 2017 John Wiley & Sons, Ltd.

Role of carbonate phase in ceria–carbonate composite for low temperature solid oxide fuel cells: A review

Abstract: Summary Ceria–salt composites represent one type of promising electrolyte candidates for low temperature solid oxide fuel cells (LT-SOFCs), in which ceria–carbonate attracts particular attention because of its impressive ionic conductivity and unique hybrid ionic conduction behavior compared with the commonly used single-phase electrolyte materials. It has been demonstrated that the introduction of carbonate in these new ceria-based composite materials initiates multi new functionalities over single-phase oxide, which therefore needs a comprehensive understanding and review focus. In this review, the roles of carbonate in the ceria–carbonate composites and composite electrolyte-based LT-SOFCs are analyzed from the aspects of sintering aid, electrolyte densification reagent, electrolyte/electrode interfacial ‘glue’ and sources of super oxygen ionic and proton conduction, as well as the oxygen reduction reaction promoter for the first time. This summary remarks the significance of carbonate in the ceria–carbonate composites for low temperature, 300–600 °C, SOFCs and related highly efficient energy conversion applications. Copyright © 2016 John Wiley & Sons, Ltd.

Investigation of solar hybrid system with concentrating Fresnel lens, photovoltaic and thermoelectric generators

Abstract: Summary An experimental model of a solar hybrid system including photovoltaic (PV) module, concentrating Fresnel lens, thermoelectric generator (TEG), and running water heat extracting unit was created and studied. The PV module used was of c-Si and TEG of Bi2Te3; the Fresnel lens (solar concentrator) and TEG share an optical train, whereas PV module was illuminated separately with non-concentrated light. Heat extracting unit operated in thermo siphon mode. In climatic conditions of Mexico (Queretaro, 20o of North latitude, summer time), the Fresnel lens accepted 120 W of solar radiation power, and the system generated 7.0 W of electric power and 30 W of thermal one. The discussion is made of the possible characteristics of a hypothetical hybrid system where all its elements share the same optical train. Copyright © 2016 John Wiley & Sons, Ltd.

Enhanced bioremediation of toxic metals and harvesting electricity through sediment microbial fuel cell

Abstract: Summary Performance of sediment microbial fuel cells (SMFCs) with aerated (A-SMFC) and nonaerated (NA-SMFC) cathodes was evaluated at different operating conditions in toxic metal removal and power generation. The A- and NA-SMFC open-circuit voltages were respectively about 665 and 275 mV, with quite steady performances for 120 days. The cell design points of both SMFCs were calculated by implementing polarization curves, and they were at 1 kΩ (power density 8.1 mW/m2 and current density 0.0504 mA/m2 with voltage 150 mV) for NA-SMFC and 100 Ω (power density 252.81 mW/m2 and current density 0.954 mA/m2 with voltage of 275 mV) for A-SMFC, respectively. Cathode potentials were at 30 kΩ 290 mV (NA-SMFC) and 500 mV (A-SMFC). As to the anode, at 30 KΩ, it was −180 mV (NA-SMFC) and 190 mV (A-SMFC). The voltammetry profiles of A-SMFC showed maximum current (forward scan, 22.7 μA; reverse scan, −19.4 μA) followed by NA-SMFC (forward scan, 11.3 μA; reverse scan, −9.5 μA). The cell design points of A-SMFC and NA-SMFC were altered after pH and temperature amendments at 200 and 700 Ω, respectively. As to metal removal rate, the maximum arsenic cadmium and lead removal was observed in A-SMFC at pH 7.0 (77.70%, 90.86%, and 83.91%) and 45°C (66.22%, 79.03%, and 71.17%). Scanning electron microscopy confirmed, at pH 7.0 and 45°C, an optimal biofilm growth at cathode and anode graphite of both SMFCs. After 120 days of operation, genomic DNA was extracted from biofilms and analyzed for rDNA 16S sequences. Similarity search was performed by using Basic Local Alignment Search Tool algorithm against the National Center for Biotechnology Information Gen Bank showing Pseudomonas spp. dominance at both anode and cathode. The results revealed that the A-SMFC system could be employed as an effective and long-term tool for power generation as well as stimulated bioremediation of the polluted sediments.

Modeling and performance analysis of duck-shaped triboelectric and electromagnetic generators for water wave energy harvesting

Abstract: Summary Triboelectric nanogenerator (TENG) is a newly proposed technology for effectively converting mechanical energy into electricity. Triboelectric nanogenerator has shown a great potential for harvesting the clean and abundant energy of ocean waves. Recently, a duck-shaped TENG device has been proposed as a lightweight, cost-effective, highly stable, and efficient system for scavenging the existing energy in water waves. In this paper, a detailed investigation on the performance of the duck-shaped TENG is presented. Then, a comparative analysis between the TENG device and an equivalent electromagnetic generator (EMG) for wave energy harvesting is performed. The electric output characteristics of both techniques under various mechanical and electrical conditions are obtained. The analysis demonstrates that at a low operating frequency of 2.5 Hz, the TENG and EMG achieve the peak power density of 213.1 and 144.4 W/m3, respectively. The present paper provides guidance for design and optimization of hybrid TENG and EMG technology toward scavenging the blue energy.