Showing papers in "Journal of energy storage in 2020"

A review of energy storage types, applications and recent developments

Abstract: Energy storage technologies, including storage types, categorizations and comparisons, are critically reviewed. Most energy storage technologies are considered, including electrochemical and battery energy storage, thermal energy storage, thermochemical energy storage, flywheel energy storage, compressed air energy storage, pumped energy storage, magnetic energy storage, chemical and hydrogen energy storage. Recent research on new energy storage types as well as important advances and developments in energy storage, are also included throughout.

Digital twin for battery systems: Cloud battery management system with online state-of-charge and state-of-health estimation

Abstract: Battery management is critical to enhancing the safety, reliability, and performance of the battery systems This paper presents a cloud battery management system for battery systems to improve the computational power and data storage capability by cloud computing With the Internet of Things, all battery relevant data are measured and transmitted to the cloud seamlessly, building up the digital twin for the battery system, where battery diagnostic algorithms evaluate the data and open the window into battery’s charge and aging level The application of equivalent circuit models in the digital twin for battery systems is explored with the development of cloud-suited state-of-charge and state-of-health estimation approaches The proposed state-of-charge estimation with an adaptive extended H-infinity filter is robust and accurate for both lithium-ion and lead-acid batteries, even with a significant initialization error Furthermore, a state-of-health estimation algorithm with particle swarm optimization is innovatively exploited to monitor both capacity fade and power fade of the battery during aging The functionalities and stability of both hardware and software of the cloud battery management system are validated with prototypes under field operation and experimental validation for both stationary and mobile applications

Review of PVA-based gel polymer electrolytes in flexible solid-state supercapacitors: Opportunities and challenges

Abstract: Flexible solid-state supercapacitors with high power density and rate performance, long cycle life, high safety and ease of fabrication are highly desirable. They can be used in an emerging market of flexible and wearable electronic gadgets. Gel polymer electrolytes are being considered as one of the best candidates. They typically have higher ionic conductivity than solid electrolytes without safety concerns of liquid electrolytes. This article reviews the latest achievements in the application of PVA-based gel polymer electrolytes for flexible supercapacitors and new findings on the improvement of their ionic conductivity, mechanical properties, and overall electrochemical performance. Several current kinds of research attempt to overcome these challenges with the main goal of improving ionic conductivity and electrochemical properties. There is no limitation for ionic conductivity of gel electrolyte because high ionic conductivity can lead to higher specific capacitance and also sufficient electrochemical performance. A recent study of gel electrolytes has shown the highest ionic conductivity of 82 mS.cm−1 for PVA/H2SO4/Glutaraldehyde/H2O which results in a large areal capacitance of 488 mF.cm−2 (100 reference).

An IGDT-based risk-involved optimal bidding strategy for hydrogen storage-based intelligent parking lot of electric vehicles

Abstract: In a near future, electric vehicles (EVs) will constitute considerable part of transportation systems due to their important aspects such as being environment friendly. To manage high number of EVs, developing hydrogen storage-based intelligent parking lots (IPLs) can help power system operators to overcome caused problems by high penetration of EVs. In this work, a new method is applied to get optimal management of IPLs in an uncertain environment and provide optimal bidding curves to take part in power market. The main purpose of this work is to get optimal bidding curves with considering power price uncertainty and optimal operation of IPLs. To model uncertainty of power price in the power market and develop optimal bidding curve, the opportunity, deterministic and robustness functions of the information gap decision theory (IGDT) technique has been developed. Obtained results has been presented in three strategies namely risk-taker, risk-neutral, and risk-averse corresponding to opportunity, deterministic, and robustness functions of the IGDT technique. In order to demonstrate the effects of demand response program (DRP), each strategy is optimized with and without DRP cases. The mixed-integer non-linear programming model is used to formulate the proposed problem which is solved using the GAMS optimization software under DICOPT solver.

Battery thermal management with thermal energy storage composites of PCM, metal foam, fin and nanoparticle

Abstract: This study aims to analyze the thermal performance of the passive thermal management system (TMS) of the 18,650 lithium-ion battery with application of phase change materials (PCM). To improve performance of TMS, nanoparticles, fins and porous metal foam are used beside the PCM, and their effects on the system performance are compared. The local thermal non-equilibrium (LTNE) model and non-Darcy law are considered to simulate the nano-PCM melting inside the porous media. Numerical results are validated through previously published experimental data and results are presented for two, 4.6 W and 9.2 W, heat generation rates. Sole effects of adding nanoparticles to the PCM, utilizing different numbers of fins, and application of the metal foam on the system performance are scrutinized. Results indicated that the porous-PCM composition performs more efficiently than the nano-PCM and the fin-PCM ones. In addition, ΔTavg, battery parameter is introduced and its variations are analyzed to judge about the effect of each technique to reduce the battery mean temperature. Using the porous-PCM led to 4–6 K reduction in the battery mean temperature with respect to the pure PCM. Moreover, for the porous-PCM composition a delay is observed in the PCM melting initiation time that can adversely affect the performance of battery TMS.

Graphene and graphene oxide based aerogels: Synthesis, characteristics and supercapacitor applications

Abstract: Graphene and graphene-based materials have a high potential, especially in energy storage technology. Thanks to the three-dimensional (3D) structures developed with this material, their importance in the production and application of energy storage devices has increased. Studies on supercapacitor applications of graphene-based aerogels have begun to arouse interest in recent years. In this study, recent studies on aerogel supercapacitors, in which researchers have shown great interest, have been compiled and collected. In this study, production methods and properties of graphene oxide, properties and production of aerogels, production and applications of graphene/graphene oxide aerogels are discussed. In this way, the data is presented and discussed in an organized way for the researchers who study or who want to study in this field.

Phase change materials and energy efficiency of buildings: A review of knowledge

Abstract: Nowadays, the energy efficiency of buildings is one of the biggest preoccupations, due to the high negative impacts in the environment, economy and society. The utilization of phase change materials (PCM) in construction industry was been developed by several authors around the world. In this study, the connections between the PCM, energy efficiency and energy poverty are presented. The main PCM characteristics and an exhaustive description of the PCM application in buildings, more specifically in walls, floors, ceilings and glazed areas, are also presented.

Optimal scheduling of a renewable based microgrid considering photovoltaic system and battery energy storage under uncertainty

Abstract: This paper suggests a new energy management system for a grid-connected microgrid with various renewable energy resources including a photovoltaic (PV), wind turbine (WT), fuel cell (FC), micro turbine (MT) and battery energy storage system (BESS). For the PV system operating in the microgrid, an innovative mathematical modelling is presented. In this model, the effect of various irradiances in different days and seasons on day-ahead scheduling of the microgrid is evaluated. Moreover, the uncertainties in the output power of the PV system and WT, load demand forecasting error and grid bid changes for the optimal energy management of microgrid are modelled via a scenario-based technique. To cope with the optimal energy management of the grid-connected microgrid with a high degree of uncertainties, a modified bat algorithm (MBA) is employed. The proposed algorithm leads to a faster computation of the best location and more accurate result in comparison with the genetic algorithm (GA) and particle swarm optimization (PSO) algorithm. The simulation results demonstrate that the use of practical PV model in a real environment improve the accuracy of the energy management system and decreases the total operational cost of the grid-connected microgrid.

Recent progress of advanced energy storage materials for flexible and wearable supercapacitor: From design and development to applications

Abstract: Wearable electronic devices, such as electrical sensors, flexible displays, and health monitors have gained considerable attention and experienced rapid progress. Recently, the progress of flexible and wearable supercapacitors (SCs) have received considerable attention due to their ease of fabrication, low cost, flexible integration into textiles, long cycle life, fast charging/discharging, high efficiency, and capability to bridge the energy/power gap between conventional capacitors and batteries/fuel cells. In this context, the recent progress and achievements of flexible and wearable supercapacitors are presented, especially, the rational design and synthesis of novel nanostructured electrode materials on various flexible-based substrates, such as, carbon cloth, graphene coated fabric, silver coated fabric, nickel coated fabric, copper/nickel coated polyester fabric (CNF), etc. are summarized. The latest representative techniques and active materials of recently developed wearable supercapacitors with superior performance are summarized. Lastly, the current challenges, and future research directions and perspective in optimizing and developing the energy storage performance and function of flexible and wearable supercapacitors for their practical applications are addressed.

A review of strategic charging–discharging control of grid-connected electric vehicles

Abstract: Charging–discharging coordination between electric vehicles and the power grid is gaining interest as a de-carbonization tool and provider of ancillary services. In electric vehicle applications, the aggregator acts as the intelligent mediator between the power grid and the vehicle. In recent years, researchers have introduced the concepts of aggregated energy management, centralized-decentralized planning, and ideal charging–discharging through improved technologies and integrated energy planning. These methods have the technical ability to adapt the distribution network according to load, aggregator-controlled optimal charging–discharging, demand management systems, strategic load assessments, and management. A comprehensive review suggests that large-scale electric vehicle charging technologies for controlled charging–discharging is becoming a pitfall within the grid and distribution network. This paper reviews several controlled charging–discharging issues with respect to system performance, such as overloading, deteriorating power quality, and power loss. Thus, it highlights a new approach in the form of multistage hierarchical controlled charging–discharging. The challenges and issues faced by electric vehicle applications are also discussed from the aggregator's point of view.

Experimental study on tubular solar still using Graphene Oxide Nano particles in Phase Change Material (NPCM's) for fresh water production

Abstract: Storing of energy in the form of latent or sensible heat is the best method in improving the performance of any thermal application. Desalination using renewable energy is the best method in getting potable water and due to its lower performance and yield it is not commercially available. The present investigation deals with improving potable water produced using nanomaterial in phase change material from a tubular solar still. Three different solar still namely TSS, TSS with PCM and TSS with NPCM were used in the present study and tested under the climatic conditions of Chennai, India. The thermal conductivity of graphene oxide nanoparticle in PCM acts as the key role in improving the thermal performance as the thermal conductivity of NPCM improved by 52% compared to that of PCM without nanoparticle. There is no significant improvement in the thermal conductivity of nano enhanced PCM with concentration beyond 0.3%. With a significant improvement in the thermal conductivity of NPCM, the water temperature increased by 7 °C and 3 °C as compared to TSS loaded with PCM and TSS without PCM respectively. The maximum enhancement in temperature of NPCM is found as 24% and the temperature is higher during off shine hours compared to that of PCM without nanoparticle. Similarly, with improved water temperature using NPCM as energy material, the evaporation rate from the absorber is improved by 41.3%, whereas, the average EHTC for TSS and TSS loaded with PCM alone is improved by 32.76 and 34.32% respectively. The total cumulative yield produced per m2 area from TSS, TSS with PCM, and TSS with NPCM is found to be 2.59, 3.35 and 5.62 kg respectively. Results also revealed that the daily efficiency of TSS with NPCM is improved to about 116.5% and comparatively higher than TSS with PCM and conventional tubular solar still.

Research progress on power battery cooling technology for electric vehicles

Abstract: In the charging and discharging process of new energy vehicles, how to maintain power battery within optimum operating temperature range, reduce the peak temperature and temperature difference, which is a problem needs to be paid attention to. Proper cooling technology can reduce the negative influence of temperature on battery pack, effectively improve power battery efficiency, improve the safety in use, reduce the aging rate, and extend its service life. In this context, several battery thermal management systems(BTMS) are reviewed, including air cooling BTMS, liquid cooling BTMS and refrigerant direct cooling BTMS in traditional battery thermal management system; phase change material-based BTMS, heat pipe-based BTMS and thermoelectric element-based BTMS in new battery thermal management system. In order to reduce negative influence of excessive temperature on the battery pack, and to seek feasible solutions for BTMS in future development, the above six power battery cooling technologies are discussed. Summarize the research emphases and research progress of different BTMS at present. Objectively evaluate the advantages and disadvantages of each BTMS. Considering actual working conditions, the installation feasibility, as well as economic benefits of each BTMS, then discuss proper solutions, and predict future development trends reasonably. Finally, analyze and discuss the differences and gaps between traditional and new BTMS. Providing a reference for designing the best BYMS solution. Ensuring the battery is in the optimum operating temperature range, maintain the BTMS stable operation, and improve battery conversion efficiency, providing valuable solutions for the BTMS research in the future.

An intuitive review of supercapacitors with recent progress and novel device applications

Abstract: Supercapacitors (SCs) possess paramount importance and are a promising solution among the class of energy storage devices since they have appreciable features like higher specific power, longer life span, and eco-friendly nature. They replace the difference of energy/power between the high-power traditional capacitors and high energy fuel cells/ batteries. In the current review, comprehensive research on the recent literature of SCs investigates and elucidates with great consideration. The global market analysis, manufacturing firms, challenges, and recent advances present the fundamental, as well as application perspective of SCs. An elaborate analysis of the classifications of SCs, fabrication of different electrode materials from the very beginning of their evolution gives the lucid idea. The evaluation of SC nanocomposites with different parameters such as specific capacitance, energy density, power density, cycling performance, and capacity retention depicts the performance. Detail description of the selection of electrolytes and various synthesis methods of the SCs explains comprehensively. In the end, future scope and challenges mention briefly and consider for the next-generation SC's design and applications. This review provides a reference point on the SCs for researchers and designers working in the field of energy storage devices and applications.

The Development of Stationary Battery Storage Systems in Germany - A Market Review

Abstract: The market for stationary battery storage systems (BSS) has been growing strongly around the world for several years. The areas of application for BSS range from ancillary services, to reductions in commercial power prices, to an increase in solar self-consumption in private homes. This wide range of applications, combined with the strong market growth, has led to significant research in the field of BSS. The central topics of these research activities include the simulation of BSS in renewable energy systems, the development of operating strategies and the economic evaluation of these. However, the young market lacks transparency and the underlying assumptions about prices and battery dimensions often do not correspond to reality. To address this issue, this paper provides detailed information about the markets of home storage systems (HSS), industrial storage systems (ISS), and large-scale storage systems (LSS) in Germany. We have been continuously building a database on the HSS and ISS market with accompanying research on subsidy programs and additional research. Furthermore, we have compiled the dataset on LSS in parallel through constant research and publish it with this paper. Our analyses show that by the end of 2018, a total of 125,000 HSS, with a battery power of about 415 MW and battery capacity of 930 MWh, had been installed in Germany. The current state of the ISS database, however, does not allow sharp estimates on the overall German ISS market, but shows the wide capacity and power ranges from some kW / kWh to nearly one MW / MWh for these systems. The 59 LSS have an accumulated power of 400 MW and a capacity of about 550 MWh. They operate mainly in the market of frequency containment reserve (FCR). Lithium-ion technologies dominate the HSS and LSS markets with high shares. The specific prices of this technology have fallen by more than 50% in recent years and were around 1,150 €/kWh in the HSS market and 800 €/kWh in the LSS market in 2018. Our results provide a solid basis for further research on the current and future status of BSS. Research from around the world can adapt the results pertaining to Germany as one of the pioneering markets to other countries.

Energy management of wind-PV-storage-grid based large electricity consumer using robust optimization technique

Abstract: Large electricity consumers (LEC) can purchase energy from various energy resources such as bilateral contracts, pool market, micro-turbines, battery storage systems, wind turbines, photovoltaic panels (PV). The uncertainty of market price leads to uncertainty in the total cost to the LEC. Therefore, in this article, the robust optimization (RO) technique is provided to investigate the uncertainty of the pool market price in the presented problem. Also, demand response program (DRP) is provided to decrease the purchased cost to the LEC as much as possible. According to the obtained results, without considering DRP, purchased cost is approximately $40,253.252 and $42,586.984, respectively in the risk-neutral strategy (ideal condition) and robust strategy (worst condition). Furthermore, the purchased cost is reduced nearly $36,945.362 and $39,789.267 in the risk-neutral and robust strategies with considering DRP. So, it can be concluded that the purchased cost to the LEC with considering DRP is reduced 8.2% and 6.5% in risk-neutral and robust strategies, respectively.

Techno-economic assessment of energy storage systems using annualized life cycle cost of storage (LCCOS) and levelized cost of energy (LCOE) metrics

Abstract: Energy generation from renewable energy sources (RESs) is rapidly developing across the world to improve the performance of power networks and increase the share of RESs in world energy production. In this regard, energy storage (ES) technologies are the key enablers for reliable use of renewables because they introduce many benefits for modern power systems. However, the choice of a suitable technology depends on several techno-economic metrics, which require the decision-maker to investigate the applicability of the technology and whether it offers promising benefits or not. Hence, this paper presents an ES cost model that considers long-term, medium-term, and short-term ES applications, technologies and technical characteristics in an integrated framework that consider the ES technical and economic characteristics supported by in-market insight, including capital costs of the technologies; operation and maintenance costs; replacement costs during the lifetime of the system; and disposal and recycling costs, based on the current ES costs. Two key metrics, namely the annualized life cycle cost of storage (LCCOS) and the levelized cost of energy (LCOE), are used to make proper ES operational choices while complying with their technical and operational performance limits. Further, a sensitivity analysis of the governing factors that affect the storage cost is presented to introduce a powerful decision tool to empower techno-economic assessment of ES systems using the proposed cost models.

A novel deep learning framework for state of health estimation of lithium-ion battery

Abstract: The state-of-health (SOH) estimation is a challenging task for lithium-ion battery, which contribute significantly to maximize the performance of battery-powered systems and guide the battery replacement. The complexity of degeneration mechanism enables data-driven methods to replace mechanism modeling methods to estimate SOH. The insight that motivates this study is that the charging curve of constant current-constant voltage charging mode could reflect the magnitude of SOH from the perspective of capacity. The proposed approach is based on a hybrid neural network called gate recurrent unit-convolutional neural network (GRU-CNN), which can learn the shared information and time dependencies of the charging curve with deep learning technology. Then the SOH could be estimated with the new observed charging curves such as voltage, current and temperature. The approach is demonstrated on the public NASA Randomized Battery Usage dataset and Oxford Battery Degradation dataset, and the maximum estimation error is limited to within 4.3%, thus proving its effectiveness.

Improving the trays solar still performance using reflectors and phase change material with nanoparticles

Abstract: The potable water shortage is a big problem facing the governments and decision-makers everywhere. Solar distiller is one of the techniques that participate in solving this problem. In this work, the impact of internal reflectors on the trays distiller performance was investigated. Besides, the influence of painting the surfaces of the solar still by the mixture of black paint and copper oxide (CuO) nanoparticles was studied. This is to enhance the heat transfer characteristics between the basin surfaces and water. Finally, the impact of using the paraffin wax mixed with CuO nanoparticles as a phase change material (PCM) on the performance of trays distiller was evaluated. Experimental results revealed that the total freshwater yield of the trays distiller was improved by 57, 14, 70.7, and 108% when using reflectors, CuO nanoparticles in paint, reflectors and nano-coating, and the collection of reflectors, nano coating, and PCM with CuO nanoparticles respectively over that of the reference still. Also, the total accumulated freshwater of the conventional and trays solar stills reached 2400 and 5000 mL/m² a day, respectively. Moreover, the thermal efficiency of the trays distiller with reflectors, nano-paint coating, and PCM-CuO nanoparticles mixture was 51.5%.

Natural convection flow of a suspension containing nano-encapsulated phase change particles in an eccentric annulus

Abstract: The free convective flow of a Nano-Encapsulated Phase Change Material (NEPCM) suspension in an eccentric annulus is investigated numerically. The inner cylinder is heated and kept at a temperature higher than that of the outer cylinder. The core of the NEPCM particles is made of nonadecane while the shell is made of Polyurethane. The nanoparticles are dispersed in water as the base fluid. The equations governing the flow and heat transfer of the NEPCM suspension in the annulus are developed and written in the non-dimensional form. The numerical solutions of these equations are obtained using the finite element method. The validity of the numerical method is ensured by comparing its predictions to the results of previously published studies. The main outcomes point out to the impact of the volume fraction of the NEPCM particles and Stefan number on the thermal and hydrodynamic characteristics of the suspension. A 5% volume fraction represents the optimal value for heat transfer enhancement. Heat transfer is also enhanced when the fusion temperature of the NEPCM core is far from the temperatures of the hot and cold walls. Furthermore, increasing the annulus eccentricity and moving the inner cylinder towards the top tends to inhibit heat transfer in the annulus.

Experimental investigation of energy storage properties and thermal conductivity of a novel organic phase change material/MXene as A new class of nanocomposites

Abstract: Energy storage is a global critical issue and important area of research as most of the renewable sources of energy are intermittent. In this research work, recently emerged inorganic nanomaterial (MXene) is used for the first time with paraffin wax as a phase change material (PCM) to improve its thermo-physical properties. This paper focuses on preparation, characterization, thermal properties and thermal stability of new class of nanocomposites induced with MXene nanoparticles in three different concentrations. Acquired absorbance (UV-Vis) for nanocomposite with loading concentration of 0.3 wt.% of MXene achieved ~39% enhancement in comparison with the pure paraffin wax. Thermal conductivity measurement for nanocomposites in a solid state is performed using a KD2 PRO decagon. The specific heat capacity (cp) of PCM based MXene is improved by introducing MXene. The improvement of cp is found to be 43% with 0.3 wt.% of MXene loaded in PCM. The highest thermal conductivity increment is found to be 16% at 0.3 wt.% concentration of MXene in PCM. Decomposition temperature of this new class of nanocomposite with 0.3 wt.% mass fraction is increased by ~6%. This improvement is beneficial in thermal energy storage and heat transfer applications.

Phase change materials integrated solar thermal energy systems: Global trends and current practices in experimental approaches

Abstract: Solar thermal systems (STSs) are gaining boom in the globalized market since last two decades to combat the menace of global warming. Considerable research has been carried out in the field of solar thermal system for efficiency enhancement. Improvement in terms of efficiency and performance would make solar thermal systems a better option for replacing the conventional energy systems. Phase change Materials (PCMs) have emerged as an alternative to enhance the performance of the solar heating systems by acting as thermal storage batteries. In this review article an attempt has been made to consolidate the global trends and practices that has been underwent incorporating Phase change materials (PCMs) in solar thermal systems. Research on PCM based solar cooker has found to be extinct. PCM based PCM based high temperature power plant applications are on current trends of research. Application of phase change materials for low, medium and high temperature solar thermal systems are comprehensively reviewed and discussed in this article. As well the environmental benefits in terms decline in CO2 emission, due to the use of STS in day-today life and the economic analysis of PCM based STS in terms of cost and payback period is presented.

Robust electrochemical performance of polypyrrole (PPy) and polyindole (PIn) based hybrid electrode materials for supercapacitor application: A review

Abstract: One of the basic intentions of science and technology is the evolution of novel and more efficient devices to make human life more easy and comfortable. A supercapacitor is one such device that can be utilized as a complementary and to some extent a replacement of electrochemical battery to store electrical energy. The performance of a supercapacitor very much depends on the electrode material used and hence a variety of materials are employed to form electrodes of supercapacitors in order to improve its performance. In this review, we have discussed the preparation and properties of polypyrrole (PPy) and polyindole (PIn) based electrode material for supercapacitor applications. PPy shows a high degree of flexibility which makes it markedly suitable and applicable for making flexible supercapacitors. PIn exhibit slow hydrolytic degradation and hence long charge-discharge time. Thus, PIn can be utilized to form supercapacitors having the ability to store energy for a longer period of time. Nonetheless, their properties can be enhanced by using binary and ternary composites of PPy and PIn with different carbon-based and metal-based materials. This review briefly discusses some of these composites and devices formed by them.

Carnot battery technology: A state-of-the-art review

Abstract: The growth of renewable energy requires flexible, low-cost and efficient electrical storage to balance the mismatch between energy supply and demand. The Carnot battery buffers electrical energy by storing thermal energy (charging cycle mode) from a resistive heater or a heat pump system when the electricity production is higher than the demand. When electricity demand is higher than the production, the Carnot battery generates power from the stored thermal energy (power cycle mode). This paper is a review of this emerging and innovative technology, including a market analysis. First, the different possible technologies and configurations of Carnot batteries are described. This includes charging cycles, power cycles and thermal energy storage systems. Furthermore, a state-of-the-art of the existing prototypes in the world is given. The performance indicators for this technology are unclear, and this paper tries to define objective performance indicators. Finally, all the described technologies are compared, and conclusions are drawn to help engineers select the optimal technology for a given case.

Systematic review of encapsulation and shape-stabilization of phase change materials

Abstract: In the development of renewable energies, thermal energy storage (TES) has become a key opportunity to relieve to some extent the increase in energy demand and supply. The past two decades have seen increasingly advances in the field of phase change materials (PCM) as latent heat storage systems, being one concern their containment when using solid to liquid PCM. The purpose of this paper is to review the state-of-the-art of shape-stabilization (SS-PCM) and encapsulation (CS-PCM) of organic PCMs for low thermal applications (

Energy efficiency optimization of the waste heat recovery system with embedded phase change materials in greenhouses: A thermo-economic-environmental study

Abstract: The continuous increase of greenhouse gas emission and the growing cost of fossil fuels are two motive forces to utilize energy sources more effectively. The agricultural greenhouses are developed to supply the food resources safely and with the higher quality, especially in off-season periods of year. In developing countries like Iran, the fuel usage of the greenhouse is very high, and there is a large margin for improving heating systems. The waste heat recovery system (HRS) in two forms of with and without embedded phase change material (PCM) added to the existing heating system, and their effects studied experimentally. The HRS is a cross-flow gas flow heat exchanger with dimensions of 193cm*75cm*85 cm, which is located between the exhaust gas and the circulating air streams. The study case is a greenhouse of 20×66 m2 in city of Isfahan located nearly in central region of Iran. The mean energy efficiency improved by 40% and 33% and the 2nd law efficiency enhanced by 263% and 127% for heating systems equipped with HRSs and PCM HRS, respectively. Using PCM HRS, the inside air and exhaust gas temperatures changed by +17% and -8.2%, respectively. The fuel savings gained by using HRS with and without embedded PCM are 19% and 48% with the investment return back periods of 3 and 4 months, respectively.

A state of art review and future viewpoint on advance cooling techniques for Lithium–ion battery system of electric vehicles

Abstract: Electric Vehicles (EVs) have emerged as most promising means of transport owing to the low operational costs, high speed, and energy-efficient battery technologies, where battery thermal management system (BTMS) is possibly the most crucial element of an EV. During the charging/discharging mode of EVs, a major focused area for the researcher is to maintain the optimal working temperature range of the batteries and reduce both the maximum temperature and temperature difference. Suitable and effective cooling methods can significantly reduce the adverse effect of the high surface temperature of battery cells and efficiently augments the battery thermal efficiency, improves the safety of EVs, and increase the service life. In this context, this work presents a detailed state of the art review of different BTMS technologies, including natural and forced air-cooling techniques, direct and indirect liquid cooling methods, and cooling by heat pipes. It is found that the air-cooled BTMS possesses advantageous features such as safe, consistent, and simple design, but the lower heat capacity and thermal efficiency of the air as a cooling medium restricts its application to a low capacity battery. This leads to employment of forced air-cooled BTMS under high charging/discharging rate, in which air flows through the channels inside the battery packs to provide the optimum cooling. Liquid-cooled BTMS is also emerging as one of the most promising cooling technologies, which requires attention to the sealing cover during the design stage to avoid leakages. The integration of metal plates with the mini channel can effectively improve the cooling performance, but the weight of the system is a major concern. Liquid metals, nanofluids, and boiling liquids are considered as the most prominent battery cooling methods owing to their higher thermal conductivity. The advancement in hybrid cooling using fins, nanofluids, PCM along with micro channels-based cooling will significantly improve the battery performance under high charging/discharging rate and attention should be given to compact design with a cheaper cost.

A comprehensive review of future thermal management systems for battery-electrified vehicles

Abstract: Heat management is an important issue during the operation of a Li-ion battery system resulting from the high sensitivity to temperature. Nowadays, a battery thermal management system (BTMS) is employed to keep the batteries temperature in range. In a modern battery, electrified vehicles (BEVs), two types of cooling systems are employed generally separately: active and passive systems. Nonetheless, the trend in thermal management aims to improve the battery pack design to reach longer autonomy or faster charging time. However, to address these future thermal challenges, future thermal management systems are required instead of the traditional BTMSs such as air cooling or liquid cooling. However, future BTMSs has not yet been documented. Therefore, this study gives an overview of the future BTMS starting with information on the effect of temperature on LiBs in terms of high-temperature, low-temperature and safety issues. Following, the advantages and disadvantages of the existing BTMSs, which are currently used to maintain the temperature of the batteries in a safe range are exposed. Finally, the progress made on the future battery thermal management systems and their ability to overcome the future thermal challenges is reviewed. In the end, a comprehensive review classifying comparatively the existing and upcoming battery management systems is proposed, which can be seen as a first look into the future BTMSs for automotive applications.

Grasshopper optimization algorithm based two stage fuzzy multiobjective approach for optimum sizing and placement of distributed generations, shunt capacitors and electric vehicle charging stations

Abstract: In this paper a two stage Grasshopper Optimization Algorithm (GOA) based Fuzzy multiobjective approach is proposed for optimum sizing and placement of Distributed Generations (DGs), Shunt Capacitors (SCs) and Electric Vehicle (EV) charging stations for distribution systems. In the first stage Fuzzy GOA approach is used for optimum sizing and allocation of DGs and SCs for improving the substation power factor, real power loss reduction and voltage profile improvement of the distribution system. In the second stage distribution system integrated with DGs and SCs is considered and fuzzy GOA approach is used for identifying optimum locations for EV charging stations and number of vehicles at the charging stations. EV battery charging load models are developed from the Lithium ion battery charging characteristic curves for load flow analysis. Simulation results are shown to show the advantages of fast converging properties of GOA over GA and PSO techniques. Simulation results are demonstrated on 51 bus and 69 bus distribution networks to show the advantages of proposed methodology compared to conventional objective based simultaneous optimization approach. The effect of EV load growth and the effect of uncertainties in DGs and distribution system load are shown on the distribution system performance.

Stability study and optimization design of small-spacing two-well (SSTW) salt caverns for natural gas storages

Abstract: A small-spacing two-well salt (SSTW) cavern is a relatively new type of cavern. As this type of cavern is less frequently used in underground natural gas storages, study on its stability is quite limited. To promote the application of this type of cavern and accelerate the construction of underground salt cavern gas storages, stability analysis and optimization design of this type of cavern are indispensable to the security of underground natural gas storages. In this paper, numerical calculation and parameters analysis were performed to analyze the effects of internal gas pressure and ratio of long axis to short axis (RLS) on the stability of SSTW caverns. The results show that internal gas pressure has an influence on the stability of SSTW caverns and low pressure should be limited in terms of duration and magnitude. And the ratio of long axis to short axis (RLS) has limited influence on the stability of a SSTW cavern by ways of volume loss rate and roof settlement. Overall, the SSTW cavern behaves similar stability state with that of a SW cavern. In addition, a flatter roof shape appears under greater Ratio value (RLS) and thus a thicker roof salt rock thickness is suggested for engineering design. The most different between them are the waist displacement along short axis, therefore the pillar width close to the adjacent cavern should be a certain lengthened at this direction.

Honeycomb-like open-edged reduced-graphene-oxide-enclosed transition metal oxides (NiO/Co3O4) as improved electrode materials for high-performance supercapacitor

Abstract: Honeycomb-like open edges reduced graphene oxide nanosheets (HOrGO NSs) filled with transition metal oxides (TMOs) as NiO/Co3O4 nanoparticles (NPs) has been synthesized by a simple and cost-effective microwave irradiation method. The microwave irradiation assisted synthesized HOrGO filled with NiO/Co3O4 NPs (HOrGO/TMOs) hybrids exhibits high specific capacitance with improved cycling stability as excellent electrode materials for supercapacitors (SCs). The HOrGO NSs contains high surface area (~570 m2 g−1) due to highly exfoliated nanostructure comprising open edges enriched morphology. In HOrGO/TMOs hybrids, the several micron-sized (~100 μm) open edges of HOrGO NSs holds the NiO/Co3O4 NPs with finely separated thin few-layer graphene NSs. The structural/ morphological analysis of synthesized HOrGO NSs and HOrGO/TMOs hybrids were extensively characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), energy dispersive X-ray spectroscopy (EDS), X-ray photoelectron spectroscopy (XPS), Raman spectra, thermogravimetric analysis (TGA) and Brunauer-Emmett-Teller (BET) surface area. The HOrGO/TMOs hybrids deliver high specific capacitance of 910 F g−1 and high robust cycling stability with capacitance retention as 89.9% after continuous 2000 cycles. The proposed mechanism explain the microwave irradiation assisted formation of HOrGO/TMOs hybrids and provides a general and low-cost approach to synthesized high quality graphene hybrids materials for SCs application.