Solar Energy Research Institute Research Articles

Peer Review Statement

All papers published in this volume have been reviewed through processes administered by the Editors. Reviews were conducted by expert referees to the professional and scientific standards expected of a proceedings journal published by IOP Publishing Publishing.• Type of peer review: Single Anonymous• Conference submission management system: Morressier• Number of submissions received: 30• Number of submissions sent for review: 28• Number of submissions accepted: 17• Acceptance Rate (Submissions Accepted / Submissions Received × 100): 56.7• Average number of reviews per paper: 1.18• Total number of reviewers involved: 17• Contact person for queries: Name: Ubaidah Syafiq Email: ubaidahsyafiq@ukm.edu.my Affiliation: Solar Energy Research Institute - The National University of Malaysia (SERI-UKM)

Preface

The inaugural International Conference on Sustainable, Renewable & Energy Efficiency (ICSREE 2022) is a conference organized by the Solar Energy Research Institute (SERI), Universiti Kebangsaan Malaysia (UKM). The primary aim of this conference is to create a holistic and hybrid platform for researchers from various backgrounds to share and learn. Besides that, a collaboration with the University of Nottingham, UK, on a special workshop of Innovation in Sustainable Cooling Technology , supported by the British Council, Malaysian Industry-Government Group for High Technology (MIGHT), and the Royal Society, is also being held as a part of this conference. Our sincerest hope is that this conference will inspire current and future generations to embrace and embark on the green and clean energy era.On behalf of the publication committees, we would like to extend our acknowledgment and gratitude for the efforts and support of the committee members, including academic staffs, administrative staffs, researchers, and postgraduate students for all their efforts and contributions. As the leading institute in renewable and green technology in Malaysia, we firmly believe that this conference will serve as a dynamic springboard for all the students and researchers involved toward critical and innovative thinking. We also hope that this conference inspires them in improving their research skills and will lead towards higher impact research in the future.List of Organizing Committees are available in this pdf.

Preface

Due to recent pandemic, 2022 8th International Conference on Applied Materials and Manufacturing Technology (ICAMMT 2022) was held virtually online on April 15th-17th, 2022. The decision to hold the virtual conference was made in compliance with many restrictions and regulations that were imposed by countries around the globe. Such restrictions were made to minimize the risk of people contracting or spreading the COVID-19 through physical contact. There were 160 individuals who attended this online conference, represented many countries.ICAMMT 2022 is to bring together innovative academics and industrial experts in the field of Manufacturing Technology and Applied Materials to a common forum. The primary goal of the conference is to promote research and developmental activities in manufacturing technology and engineering materials, and another goal is to promote scientific information interchange between researchers, developers, engineers, students, and practitioners working all around the world. The conference will be held every year to make it an ideal platform for people to share views and experiences in Manufacturing Technology, Intelligent Manufacturing and Applied Materials and related areas.During the conference, the conference model was divided into three sessions, including oral presentations, keynote speeches, and online Q&A discussion. In the first part, some scholars, whose submissions were selected as the excellent papers, were given about 5-10 minutes to perform their oral presentations one by one. Then in the second part, keynote speakers were each allocated 30-45 minutes to hold their speeches.In the second part, we invited four professors as our keynote speakers. Prof. Yajun Liu, South China University of Technology, China. His research interest is in the areas of Mechanical system signal testing, analysis, characterization, control and performance optimization. The second keynote speakers, Prof. Honggang Dong, School of Materials Science and Engineering, Dalian University of Technology, China. His research area is Refilled friction stir spot welding of aluminum alloy to galvanized steel sheets. Prof. Weiwei Zhao, Wuhan University of Technology, China. His research area includes Characterization of mechanical and mechanical properties of polymer hydrogels, research and development of biomimetic electroactive hydrogels, and applications of polymer materials in microfluidic devices and biomedicine. Lastly, we were glad to invite Prof. Md. Akhtaruzzaman, Solar Energy Research Institute (SERI) of The National University of Malaysia as our finale keynote speakers. He studied on the design and synthesis of new organic heterocyclic compounds for EL device application. Their insightful speeches had triggered heated discussion in the third session of the conference. Every participant praised this conference for disseminating useful and insightful knowledge.The proceedings are a compilation of the accepted papers and represent an interesting outcome of the conference. Topics include but are not limited to the following areas: New Materials and Advanced Materials, Advanced Design Technology, Manufacturing Systems and Automation and other related topics. All the papers have been through rigorous review and process to meet the requirements of international publication standard.We would like to acknowledge all of those who supported ICAMMT 2022. The help and contribution of each individual and institution was instrumental in the success of the conference. In particular, we would like to thank the organizing committee for its valuable inputs in shaping the conference program and reviewing the submitted papers.The Committee of ICAMMT 2022List of Committee member is available in this Pdf.

Editorial for the special issue on Sustainable Energy and Green Technologies ( SEGT 2018)

Green energy underlines the sustainable development of modern commercial and industrial activities that support economic and global population growth. However, much of the energy consumed today comes from fossil fuels that negatively affect human health and the environment. The discovery and advancement in sustainable energy and green technology will help to bring humanity closer to a sustainable future. There are various forms of sustainable energy sources (solar, wind, hydro, geothermal, biofuels, wave, tidal, and others) that can be incorporated by countries to minimize the use of fossil fuels. According to the International Energy Agency (IEA), renewable energy resources’ share is expected to reach 30% by 2024. The cost of solar and wind power continues to fall, making them increasingly competitive in the power generation market. In addition to sustainable energy generation, getting a promising solution to store sustainable energy is a crucial issue. Battery energy storage is a good option for small independent power systems to store small amounts of excess renewable electricity for short durations. For long-term energy storage, hydrogen production via a power-to-gas system has been shown to be the most cost-effective approach. To conclude, the increasing deployment of sustainable energy and green technology is important to tackle greenhouse gas emissions, reduce air pollution, and expand energy access. The International Conference on Sustainable Energy and Green Technology 2018 (SEGT 2018) was held on 11-14 December 2018 in Kuala Lumpur, Malaysia. It was jointly organized by the University of Malaya, University Tunku Abdul Rahman, National I-Lan University, National Cheng Kung University, Beijing Institute of Technology, Qinzhou University, National Taipei University of Technology, National Dong Hwa University, University of Hong Kong, and City University of Hong Kong. SEGT 2018 was also supported by the UM Centre for Energy Sciences, UKM Solar Energy Research Institute, IET Malaysia Chapter, and ASHRAE Malaysia Chapter. The conference aims to promote research in the fields of sustainable energy, green technology, environment, and climate change and to facilitate the exchange of new ideas in these fields among academicians, engineers, scientists, and practitioners. SEGT 2018 with the theme “Innovations for Green-Energy Technologies” has drawn over 370 participants (with more than 270 oral presentations and posters) from more than 20 countries around the world. It has covered plenary, keynote, and invited speeches (with speakers from academy and industry), oral presentations, and poster sessions on different aspects of energy research. Eight distinguished plenary, keynote, and invited speakers from internationally reputed institutes have presented state-of-the-art research, development, innovative advances, and its related issues in sustainable energy and green technology. Relevant discussions were fostered in the various fields related to bioenergy and biofuels, renewable energy, and smart energy systems, energy efficiency and green building, energy and environmental policy, environmental and climate science, and mitigation technology, green material, design, products and manufacturing processes, and other energy conversion technologies. We would like to thank the SEGT 2018 advisory board members, organizing and scientific committees, speakers, authors, session chairs, and all attendees, whose contributions and efforts have made this conference a success. This special issue is a dedicated compilation of recommended papers from SEGT 2018 and some invited papers. All papers in this special issue on “Sustainable Energy and Green Technologies” were subjected to another round of peer-to-peer review process for further quality improvement prior to publication. We believe that this special issue will make a significant contribution to the vast fields of energy research. We greatly appreciate the support and contributions of all contributing authors and reviewers. We would also like to take this opportunity to thank Prof Dr Ibrahim Dincer and the editorial team of Wiley, all contributing authors, reviewers, and our assistants for their efforts that have made this special issue a true success.

Special Section: Memorial Festschrift for the Late Professor Frank Kreith Sunrise Delayed but the Sun Shines Brightly: The Energy-Sustainability Quandary and Legacy of Professor Frank Kreith

Special Section: Memorial Festschrift for the Late Professor Frank Kreith Sunrise Delayed but the Sun Shines Brightly: The Energy-Sustainability Quandary and Legacy of Professor Frank Kreith

Foreword: The 2019 Conference on Fundamental and Applied Science for Advanced Technology (ConFAST 2019)

We are pleased to present you the Proceeding of The 2019 Conference on Fundamental and Applied Science for Advanced Technology (ConFAST 2019). Held in Yogyakarta on January 25th 2019, the conference is organized by Universitas Ahmad Dahlan (UAD) and supported by local and international partners such as Center for Science and Accelerator Technology (PSTA-BATAN), Center for Volcanology and Geological Hazard Mitigation (BPPTKG), Prince of Songkla University (PSU), Universiti Brunei Darussalam (UBD), and Solar Energy Research Institute of Singapore (SERIS).The 2019 ConFAST themed “Bridging the Gap: from Academic Research to Industrial Applications”, aimed to strengthen the society with advanced science and technology in the wake of industrial revolution 4.0 in two folds: (1) Empowering the sci-tech-based enterprize by adopting advanced science and technology to compete globally and, (2) Imparting meaningful purpose on academic research through research to solve a real problems encountered by societies and industries.The 421 contributors from academics, government agencies and industries, who contribute 189 abstracts on the field of maritime, energy and advanced materials, disaster mitigation to intelligent systems, truly make the conference a unique platform for a productive, interdisciplinary exchange of ideas. Out of 189 paper presented, 54 manuscripts passed the academic peer review process and are included in this proceeding volume.The success of this conference cannot be achieved without the involvement from numbers of individuals. We would therefore, express our sincere gratitude to all of the organizing committees, scientific committees, keynote speakers, presenters, participants, and all contributors who have put their finest effort to make this conference a big success. Finally, I hope all participants have gained a rewarding experience from the event.Sincerely,Damar Yoga Kusuma, Ph.D.Editor in Chiefwebsite: http://confast.orgemail: confast@uad.ac.List of image is available in this pdf.

Welcome Message from the Dean, Faculty of Applied Science and Technology (FAST)

On behalf of the faculty member of FAST, Universitas Ahmad Dahlan, we are delighted to welcome you to The 2019 Conference on Fundamental and Applied Science for Advanced Technology (ConFAST 2019). The Conference in this series has been successfully organized in the previous events starting from 2012 (ICGWBt), 2014 (ICGWBT) and 2016 (ConFAST). Since then, ConFAST has become a “trademark” scientific forum for our faculty to interact with local, regional and international partners.I would like to express my sincere gratitude to the distinguished keynote speakers for sharing their expertise in our forum, especially for Prof. Setiawan from Universitas Brawijaya, Dr. Warsito P. Taruno from CTECH Laboratory, Prof. Afroz Ahmad Shah from Universiti Brunei Darussalam, Dr. Abhishek Kumar from Solar Energy Research Institute of Singapore, and Prof. Kitichate Sridith from Prince of Songkla University. I hope this conference can serve as initial step stone for a productive collaboration in the near future. Gratitude also goes to all presenters and participant for their active contribution to the conference, we hope to seeing you again in the next series of ConFAST 2021. Also, I would like to congratulate the organizing committee and editorial boards for their rigorous efforts in preparation, execution, and post publication of the conference.Last but not least, I sincerely hope that all the presenters and participants will benefit from the technical contents, as well as genuine strategic networking forged through this conference.Sincerely,Imam Azhari, M.CS.Dean, Faculty of Applied Science and TechnologyUniversitas Ahmad DahlanList of image is available in this pdf.

Effects of circumsolar radiation on the optimal performance of a Stirling heat engine coupled with a parabolic dish solar collector

This paper investigates the effects of circumsolar radiation on the optimal performance of a coupled parabolic dish and a Stirling heat engine, referred to as the Dish/Stirling system. The presence of circumsolar radiation results in the widening of the solar cone in which the solar beam (direct) radiation is received by the parabolic dish. This beam radiation cone enlargement effectively degrades the collector performance, especially for the very high concentration ratio collectors such as the parabolic dish. The enlarged solar beam radiation cone angular width results in enhanced solar radiation flux spillage at the receiver due to the inability of the parabolic dish reflector surface to focus a significant fraction of incoming beam radiation. This reduces both the energy input as well as the maximum temperature of the Stirling heat engine cycle and causes a reduction in the overall thermal efficiency of the Dish/Stirling system. The present study analyzes this effect by considering various levels of circumsolar radiation, characterized by a parameter known as the circumsolar ratio. The data for the intercept factor of the parabolic dish collector is based on the circumsolar radiation measurements obtained by researchers at the Lawrence Berkeley Laboratory, and the results of analysis reported by researchers at the Solar Energy Research Institute (currently the National Renewable Energy Laboratory). For the present analysis, this intercept factor data is curve-fitted for different circumsolar ratio, mirror optical errors and the concentration ratio using a MATLAB® program. The overall thermal efficiency of the Dish/Stirling system is maximized with respect to the concentration ratio of the parabolic dish and the maximum temperature ratio of the Stirling heat engine using the first law of thermodynamics. This optimization process is performed using a MATLAB® program. Optimal values of concentration ratio for the parabolic dish collector, and the maximum temperature ratio of the Stirling cycle are obtained corresponding to the maximum overall thermal efficiency of the Dish/Stirling system. The study shows that, for a parabolic collector with low mirror optical error and rim angle of 60°, an increase in circumsolar ratio from 0.02 to 0.2 reduces the maximum overall thermal efficiency, optimal concentration ratio and optimal temperature ratio by about 13%, 18% and 7% respectively. In the case of parabolic collectors with high mirror optical error and rim angle of 60°, an increase in circumsolar ratio from 0.02 to 0.2 reduces the maximum overall thermal efficiency, optimal concentration ratio and optimal temperature ratio by about 10%, 11% and 5% respectively. Similar trends are observed for parabolic dish collectors with rim angle of 40°. Results from this study are presented in the form of performance charts that show the effects of varying circumsolar ratios, mirror optical errors, rim angles, non-dimensional radiation flux and non-dimensional convection loss parameters on the maximum overall thermal efficiency of the Dish/Stirling system.

International Conference on Sustainable Energy and Green Technology 2018

11-14 December 2018 Kuala Lumpur, Malaysia Conference Website: https://www.isegt.orgThe International Conference on Sustainable Energy and Green Technology 2018 (SEGT 2018) was on 11-14 December 2018 at Hotel DoubleTree by Hilton Kuala Lumpur, Malaysia. SEGT 2018 aims to promote research in the field of sustainable energy, green technology, environment and climate change, and facilitate the exchange of new ideas in these fields among academicians, engineers, scientists and practitioners. It includes plenary, keynote & invited speeches, oral presentations & poster sessions on different topics. It was co-organized by 10 universities across the Asian region (University of Malaya, University Tunku Abdul Rahman, National I-Lan University, National Cheng Kung University, Beijing Institute of Technology, QinZhou University, National Taipei University of Technology, National Dong Hwa University, University of Hong Kong and City University of Hong Kong). Besides, there are local research centers (Centre for Energy Science & Solar Energy Research Institute) and association (The IET Malaysia Chapter and ASHRAE Malaysia Chapter) that became the supporting institutions for the SEGT 2018 Conference. The conference has received more than 370 participants from 20 countries over the world such as Thailand, Canada, Taiwan, Singapore, Philippines, Indonesia, Hong Kong, China, India, Iran, Nigeria, Vietnam, Japan, Pakistan, UK, Bangladesh, Australia, Netherlands, Turkey, etc. There were 1 Plenary Speaker (Prof. Ibrahim Dincer), 3 Keynote Speakers (Prof. Chen Wei-Hsin, Prof. Dennis Y.C. Leung & Prof. Michael KH Leung) and 4 Invited Speakers (Ir. Chen Thiam Leong from ASHRAE Malaysia, Dr. Alex Lee from Tian Building Engineering, Prof. Jin Liwen from Xi’an Jiaotong University and Prof. Hans Weemaes from Neapoli) attended the conference. The conference topics are:• New and Renewable Energy• Sustainable Technologies for Energy Conversion• Energy Management, Policy, Economics and Sustainability• Energy Sciences• Energy Storage and Power Engineering• Sustainable Cities, Architecture and Green Buildings• Green Design, Products and Manufacturing Processes• Green Materials• Waste Management and Waste Water Treatment• Heating, Ventilation and Air Conditioning (HVAC)• Smart Grid / Smart City / Smart Mobility• Bioresource and BioenergyEditors (SEGT 2018 IOP-EES Conference Proceedings)Chong Wen TongWang Chin-Tsan Bernard Saw Lip Huat

Parametric analysis of Joukowski airfoil for 10-kW horizontal axis windmill

Small wind turbines are mainly used in rural areas, farms and isolated communities. These machines are supposed to be able to work within a wide range of wind speeds and usually are not equipped with pitching control mechanisms. The main objective of this study is to investigate Joukowski airfoil as an alternative for use in small power windmills (compared with the Solar Energy Research Institute, SERI airfoil as a reference) and investigate the effects on the aerodynamic performance caused by varying the tip–speed ratio and the number of blades as well as the use of blades composed of multiple airfoils. The SERI airfoils were treated using Xfoil software while the Joukowski airfoils were calculated by analytical transformation and then treated by Xfoil to estimate the aerodynamic characteristics for the different operating conditions. The data from the selected airfoils were used in a home-built numerical code based on the blade element momentum (BEM) theory. Predictions from this numerical code were compared with available experimental and numerical results to validate the numerical code. The validated code was then used to investigate parametrically two rotors of 10 kW each and verify the effects of varying the blade geometry and the tip–speed ratio on the aerodynamic loads. The Joukowski blades show higher values of torque and power at low speeds and the short chord makes these blades light and easy to startup when compared with the SERI airfoil.

Grid-Connected Semitransparent Building-Integrated Photovoltaic System: The Comprehensive Case Study of the 120 kWp Plant in Kunming, China

A 120 kWp building-integrated photovoltaic (BIPV) system was installed on the south facade of the Solar Energy Research Institute building in Yunnan Normal University. The area of the curtain wall was 1560 m2 (26 m × 60 m), which consisted of 720 semitransparent monocrystalline silicon double-glazing PV panels. This paper studied the yearly and monthly variations of power generation in terms of solar data and meteorological parameters. The total amount of power generation of the BIPV system measured from October 2014 to September 2015 was 64.607 MWh, and the simulation results with TRNSYS (Transient Systems Simulation Program) provided the 75.515 MWh predicted value of annual electricity production with the meteorological database of Meteonorm, while, based on the average value of the performance ratio (PR) of 60% and the life cycle assessment (LCA) of the system, the energy payback time (EPBT) of 9.38 years and the potential for pollutant emission reductions have been evaluated and the environmental cost is RMB ¥0.01053 per kWh. Finally, an economic analysis was carried out; the net present value (NPV) and the economic payback time of the BIPV system were estimated to be RMB ¥359,347 and 15 years, respectively.

Impact of Nonuniform Illumination and Probe Bar Shading on Solar Cell I–V Measurement

This paper examines the effect of nonuniform and probe-bar-shaded solar illumination in the I–V characterization of large area Si wafer solar cells. The illumination conditions were experimentally implemented by masking the solar cell during measurement. The results are examined in detail with simulations in Griddler, a finite element analysis software developed at the Solar Energy Research Institute of Singapore. The light I–V characteristics, particularly the fill factor, depend on the specific irradiance profiles relative to the current-collecting busbars due to effects on the effective series resistance Rs. The effect is slight for small light nonuniformities (IEC 60904 Class A nonuniformity classification or <2%) but for light nonuniformities up to 20%, the standard deviation in the fill factor can reach about 0.19% absolute. Probe bar shading directly leads to an underestimation of the measured fill factor due to longer current paths and larger voltage drops.

Record high efficiency of screen-printed silicon aluminum back surface field solar cell: 20.29%

We have achieved a record high cell efficiency of 20.29% for an industrial 6-in. p-type monocrystalline silicon solar cell with a full-area aluminum back surface field (Al-BSF) by simply modifying the cell structure and optimizing the process with the existing cell production line. The cell efficiency was independently confirmed by the Solar Energy Research Institute of Singapore (SERIS). To increase the cell efficiency, for example, in four busbars, double printing, a lightly doped emitter with a sheet resistance of 90 to 100 Ω/□, and front surface passivation by using silicon oxynitride (SiON) on top of a silicon nitride (SiNx) antireflection layer were adopted. To optimize front side processing, PC1D simulation was carried out prior to cell fabrication. The resulting efficiency gain is 0.64% compared with that in the reference cells with three busbars, a single antireflection coating layer, and a low-sheet-resistance emitter.

Research and Development Work on Solar Assisted Drying Systems

The solar energy research group from Solar Energy Research Institute (SERI), Universiti Kebangsaan Malaysia (UKM) has designed and constructed solar assisted drying systems for drying agricultural and marine products. This study is a review of numerous types of solar dryer systems developed by SERI, UKM. The classification of solar drying systems has divided by two namely air based solar collector systems and water based solar collector systems. Drying with solar assisted drying systems was found to be a viable option with many benefits such as protected drying environment, improved dried quality of products and reduces drying time compared with the traditional sun drying method. Therefore, SERI’s solar assisted drying system shows a great potential for application in drying process of agricultural and marine products.

Model-Based Techno-Economic Analysis of Battery Function for Energy Storage of Solar Energy

By its nature solar power is intermittent. Because the amount of solar power generation cannot be controlled the economic value energy from a solar array is devalued. Adding energy storage can remove the intermittent nature of solar power (see figure 1), but will increase the overall cost of electricity supplied from the system. The model developed for this study analyzes the operational characteristics and economics of adding a battery system to solar arrays in different regions around the country. The technologic and economic benefits of battery systems are assessed on an individual site basis. A system level model includes a battery component based on electrochemical and transport principles, a solar array that accounts for site-based irradiance patterns, and a dispatch and control structure that controls the flow of power between generation and demand [1]. The battery component is the focus of the system level model and is studied to understand how the battery will function under dynamic application cycling. The irradiance data for US sites was obtained from the NREL MIDC database which contains minute resolution irradiance data for all the sites studied [2]. The battery model includes a study of how variation in irradiance will affect capacity fade by including fade side reactions into the model. Metrics studied include battery sizing, battery utilization, battery degradation, system autonomy, solar energy utilization. Additionally, the economic value of systems were studied based on time-of-use pricing scenarios to determine break-even points for adding battery to solar arrays for non-utility customers. The economic analysis is informed by the battery utilization and system autonomy studied in the model. Comparisons of individual sites and solar+battery systems were studied. These model-based studies are important for determining the utility of batteries in conjunction with renewable applications. Acknowledgements The authors acknowledge financial support from the U.S. Department of Energy’s Advanced Research Projects Agency- Energy (ARPA-E), and the Solar Energy Research Institute in India and the United States (SERIIUS), as well as, Washington University in St. Louis’ McDonnell Academy Global Energy and Environmental Partnership (MAGEEP).

Real Time Multi-Cell Multiple Chemistry Simulation of Reformulated Electrochemical Battery Models for EV and Grid Applications

The porous electrode pseudo-two-dimensional (P2D) model which includes several meaningful internal variables (including potentials and concentrations in solid and liquid phase) provides good predictive capability for battery simulation1. We have performed an orthogonal collocation reformulation of the P2D model for lithium-ion batteries2,3 . The accuracy and short computation time of the reformulated model4are well suited for electric vehicle (EV) and grid application. The use of a electrochemical based model allows for the inclusion of additional physics based phenomena in the model such as temperature, stress, and capacity fade mechanisms. EV and Grid application involve large battery modules. In order to perform the most accurate simulation and control of these systems the model must include multiple cells in series parallel combination. For large modules charge balancing becomes problematic. Not all the cells will be at the same state of charge and health. In addition, for grid applications, one might visualize a situation in which lithium-ion batteries with different chemistries being used simultaneously, sometimes even flow batteries in combination with lithium-ion batteries. Systems like these require a thorough multiple cell system model to understand all of these effects. This talk will present progress in real-time simulation of physics based models for batteries in hybrid environments. Acknowledgements The authors acknowledge financial support from the U.S. Department of Energy’s Advanced Research Projects Agency- Energy (ARPA-E), and the Solar Energy Research Institute in India and the United States (SERIIUS).

Model-Based Regional Comparison of Autonomy and Battery Utilization of Energy Storage Integration with Solar Power

For intermittent renewable energy sources to be utilized beyond small penetration levels in the electric grid they must be coupled with some form of energy storage (see Figure 1). Solar power varies on two time scales. Solar trends vary seasonally, but instantaneous solar power can also vary on a minute-to minute basis because of cloud cover. This variability creates a need for a flexible form of energy storage. We used a model-based approach to study the autonomy (the percentage of time the system meets demand) and battery utilization (amount of capacity used) of a battery system tied to solar generation during yearly operation.1 Along with the variation in solar insolation seen throughout the year, we include a demand schedule which allows for different system load demands to be studied. Including demand allows for the study of different types of grid systems ranging from regional utility scale to Microgrid scale. In the study we look at Microgrid systems which include energy storage and distributed energy generation2 and include both islanded and grid-tied demand structures. Grid charging options have been incorporated into the study and allow for an economic analysis of battery utilization strategies. We used an electrochemical and transport based battery model battery model for the energy storage aspect of the system.3 For the solar portion of the model we will assess both ideal insolation curves as well as site based insolation data. For the real-site data, several solar monitoring sites within the US were studied. The real data from solar sites was obtained through an NREL database and will offer a contrasting look at how much the coupled system can be affected on a daily and seasonal basis.4 Comparisons for solar charging versus grid charging will be studied from an autonomy, utilization, and economic stand-point. System wide metrics will be used to assess the system’s operation. Acknowledgements The authors acknowledge financial support from the Solar Energy Research Institute in India and the United States (SERIIUS), as well as, Washington University in St. Louis’ McDonnell Academy Global Energy and Environmental Partnership (MAGEEP).

Modeling and Analysis of All-Vanadium Redox Static Cells

Progress made in renewable energy technologies (e.g. solar, wind and tidal energy) has fueled the research in energy storage technologies which are indispensible for the success of these intermittent sources of energy. Electro-chemical energy storage systems specially redox flow batteries (RFB) offer modular and scalable energy storage systems for large scale energy storage1. Research in different RFBs has been pursued to improve the efficiency, cost and safety aspects of these systems. While research on most aspects requires small scale (lab-scale) redox flow battery, research on some aspects can be performed and analyzed using a static cell set up (e.g. cross contamination, characterization of membrane and electrolyte etc.). These static cells (H cell) can be used to quickly estimate the performance of redox flow batteries (at least at the lab scale) including capacity loss due to cross contaminations2. Use of static cell with simplified modeling approach (including capacity loss) to validate experimental data is demonstrated by Tang et. al.2 on vanadium redox flow battery. This approach can be made more robust and general to be useful for any redox couple by combining electrochemical models and robust optimization framework (parameter and state estimation techniques) to increase the confidence in predictions made by static cell. This presentation will focus on electrochemical models for static cell with parameters and state estimation framework to increase the fidelity of results obtained by experiments performed. Acknowledgements The authors acknowledge financial support from the U.S. Department of Energy’s Advanced Research Projects Agency- Energy (ARPA-E), and the Solar Energy Research Institute in India and the United States (SERIIUS), as well as, Washington University in St. Louis’ McDonnell Academy Global Energy and Environmental Partnership (MAGEEP) and SunEdison Grant.

Two-Dimensional Modeling of Columnar TiO2 Nanostructured Electrodes

Titanium dioxide (TiO2) has recently emerged as a potential anode material for lithium ion batteries due to its low cost, abundance, and high chemical stability. There has been considerable interest in nanostructured thin films for this application since they offer higher surface area and thus better performance compared to bulk films. The performance of the anodes has previously been correlated to the morphology of these nanostructures1. Single crystalline columnar structures were shown to exhibit enhanced specific rate capacity compared to the polycrystalline granular structures for the same structure height due to sluggish diffusion kinetics in the presence of grain boundaries. Further, the performance of the columnar and granular nanostructures depended on the height of the structures. It has been reported that nanostructured TiO2 exhibits a higher capacity to store lithium due to inherent structural distortions at the nanoscale2; however, very little work has been done to mathematically correlate the nanostructure morphology to the capacitive performance of this material. Previous modeling studies of lithiation in silicon electrode nanowires have utilized atomistic and diffusion impedance models to understand Li dynamics in structures of various geometries3,4. The primary focus of most studies has been on intercalation-induced stress development and its effects on overall electrode performance, which can require finite element analysis software such as COMSOL5,6. Stress generation is an important concern in silicon due to high volumetric expansion (350%), but for TiO2, stress is a minor concern since the volume expansion upon lithiation in anatase TiO2 is only 4%.In this work, we will use a continuum-based approach7-9 to predict capacity of a TiO2 electrode for certain charging rates. To accomplish this, mathematical simulations of columnar titanium TiO2 nanostructured electrodes will be performed. The mesoscale 2D cylindrical model will be based on Butler-Volmer kinetics at the solid-electrolyte interface, which couples lithium transport in the electrolyte with insertion into the solid porous nanostructure10. The present study will attempt to simulate the effects of both columnar aspect ratio and Li diffusion in granular structures on electrode capacity at different charging rates by using experimentally derived parameters. For example, the number of grains (i.e., grain boundaries) in synthesized columnar structures will be correlated to an effective diffusivity to be used in the model, and results will be compared to existing experimental charging data. Height and aspect ratio will then be varied to determine if there exists an optimum size for these nanostructures. Acknowledgements This paper is based upon work supported in part under the U.S.-India Partnership to Advance Clean Energy-Research (PACE-R) for the Solar Energy Research Institute for India and the United States (SERIIUS), funded jointly by the U.S. Department of Energy (Office of Science, Office of Basic Energy Sciences, and Energy Efficiency and Renewable Energy, Solar Energy Technology Program, under Subcontract DE-AC36-08GO28308 to the National Renewable Energy Laboratory, Golden, Colorado) and the Government of India, through the Department of Science and Technology under Subcontract IUSSTF/JCERDC-SERIIUS/2012 dated 22nd Nov. 2012.

Gas Phase Synthesis of One-Dimensional Single Crystal Tin Oxide Nanostructured Lithium-Ion Battery Anodes

Tin oxide anodes for lithium ion batteries have recently been of considerable interest due to their high specific capacity (782 mAh/g) compared to conventional graphite electrodes (372 mAh/g). However, one of the major drawbacks with this material is the high volume expansion (≈300%) associated with the alloying and de-alloying process which results in severe mechanical damage to the material leading to rapid performance degradation. Several approaches have been adopted to reduce the mechanical damage by nanostructuring the electrode1 or by making nanocomposites of tin oxide-graphene2both of which provide better strain relaxation. However, achieving stable performance coupled with a lack of scalable manufacturing processes has so far prevented the commercial use of tin oxide as an anode material in lithium ion batteries. In this study, we present direct gas phase synthesis of one-dimensional, single crystal tin oxide nanostructures (nanocolumns) directly on a stainless steel current collector using the aerosol chemical vapor deposition (ACVD) process. This binder free approach provides several advantages3 including control of the final nanostructure morphology on the current collector; the direct attachment of each column to the current collector providing enhanced electrical contact;4 and scalable manufacturing capabilities. To further enhance the cycling performance, a reduced graphene oxide sheet (RGO) was deposited onto the nanocolumns which results in increased electrical conductivity and enhanced strain relaxation. The electrochemical performance of these nanostructures was tested in a half-cell assembly against Li/Li+. Control over the morphology of the nanostructured tin oxide was demonstrated by changing the process conditions in the ACVD reactor. For electrochemical characterization, the desired morphology of the tin oxide nanostructures was the one-dimensional columnar morphology, with a column height ranging from 0.5 – 4.0 μm depending on the deposition time and a column width of 150 – 250 nm, confirmed by scanning electron microscopy analysis (Figure 1a). High resolution transmission electron microscopy and x-ray diffraction analysis confirmed the single crystal nature of the tin oxide nanocolumns preferentially oriented along the (110) plane (Figure 1b-c). Electrochemical cycling of the bare tin oxide nanocolumns (Figure 1d) yielded an initial cycle discharge capacity of 780 mAh/g. However, the capacity degradation in the bare nanocolumns was rapid with only 53% capacity retention after 30 cycles at a cycling current density of 100mA/g. Ex-situTEM analysis shows severe mechanical damage after 30 cycles (Figure 1d inset). The electrochemical cycling of the RGO coated nanocolumns was performed to probe the improvement in the anode capacity and the cycling capability. The effects of the coating on the performance of the anode will be discussed. Electrochemical impedance spectroscopy (EIS) was used to investigate the influence of the RGO coating on the electronic properties of the anode. Acknowledgements This work is based upon work supported under the US-India Partnership to Advance Clean Energy-Research (PACE-R) for the Solar Energy Research Institute for India and the United States (SERIIUS), funded jointly by the U.S. Department of Energy (Office of Science, Office of Basic Energy Sciences, and Energy Efficiency and Renewable Energy, Solar Energy Technology Program, under Subcontract DE-AC36-08GO28308 to the National Renewable Energy Laboratory, Golden, Colorado) and the Government of India, through the Department of Science and Technology under Subcontract IUSSTF/JCERDC-SERIIUS/2012 dated 22nd Nov. 2012.