Documents published in 2017 : Scipedia

Test payment content 13
T. 177

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T. 177

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T. 177

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Nonlinear Finite Element Analysis of Reinforced Concrete L-Shaped Column Frame Joint
T. 177

Test blind review (2017).
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Mi prueba 1
J. García-Espinosa

3r Congrés d'Economia i Empresa de Catalunya - Full papers.
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Test article payment
T. 177

Test blind review (2017).

Abstract
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Congress abstract test 1
T. 177

3r Congrés d'Economia i Empresa de Catalunya - Full papers.
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Congress abstract test 1
T. 177

3r Congrés d'Economia i Empresa de Catalunya - Full papers.
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Mi prueba 1
J. García-Espinosa

3r Congrés d'Economia i Empresa de Catalunya - Full papers.
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Congress abstract test 1
T. 177

3r Congrés d'Economia i Empresa de Catalunya - Full papers.
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Stochastic Optimization of IACC Yacht Performance
T. Testing3, T. Testeando

Collection of Immunity, Inflammation and Disease (2015).
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test n1
V. Nogué

Revista Internacional de Métodos Numéricos para el Cálculo y Diseño en Ingeniería (2015).
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Agonistic anti-CD40 promotes early development and increases the incidence of severe thyroid epithelial cell hyperplasia (TEC H/P) in CD4−/− mice
S. Yu, E. Downey, H. Braley-Mullen

Collection of Immunity, Inflammation and Disease (2017).
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Immunity, Inflammation and Disease – Contributing to Quality Scientific Publishing
D. Veldhoen

Collection of Immunity, Inflammation and Disease (2017).
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The use of prebiotics during the first year of life for atopy prevention and treatment
P. Moura, N. Filho

Collection of Immunity, Inflammation and Disease (2017).
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Enhanced expression of the soluble form of E-selectin attenuates progression of lupus nephritis and vasculitis in MRL/lpr mice
K. Nakatani, S. Yoshimoto, O. Asai, H. Sakan, M. Terada, Y. Saito, M. Nose, M. Iwano, N. Konishi

Collection of Immunity, Inflammation and Disease (2017).
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Optimized fluorescent labeling to identify memory B cells specific for Neisseria meningitidis serogroup B vaccine antigens ex vivo
N. Nair, L. Buti, E. Faenzi, F. Buricchi, S. Nuti, C. Sammicheli, S. Tavarini, M. Popp, H. Ploegh, F. Berti, M. Pizza, F. Castellino, O. Finco, R. Rappuoli, G. Giudice, G. Galli, M. Bardelli

Collection of Immunity, Inflammation and Disease (2017).
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Relative contribution of IL-1α, IL-1β and TNF to the host response to Mycobacterium tuberculosis and attenuated M. bovis BCG
M. Bourigault, N. Segueni, S. Rose, N. Court, R. Vacher, V. Vasseur, F. Erard, M. Bert, I. Garcia, Y. Iwakura, M. Jacobs, B. Ryffel, V. Quesniaux

Collection of Immunity, Inflammation and Disease (2017).
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Human pre-B cell receptor signal transduction: evidence for distinct roles of PI3kinase and MAP-kinase signalling pathways
K. Anbazhagan, A. Singh, P. Isabelle, I. Stella, A. Céline, E. Bissac, B. Bertrand, N. Rémy, T. Naomi, F. Vincent, J. Rochette, K. Lassoued

Collection of Immunity, Inflammation and Disease (2017).
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Welcome to Nursing Open
R. Watson

Collection of Nursing Open (2017).
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Understanding the perceptions and experiences of Certified Registered Nurse Anaesthetists regarding handovers: a focus group study
D. Testa, S. Emery

Collection of Nursing Open (2017).
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A nurse-led intervention study: Promoting compliance with Diskus Inhaler use in asthma patients
E. Hale, R. Costello, S. Cowman

Collection of Nursing Open (2017).
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Measurement of factors that negatively influence the outcome of quitting smoking among patients with COPD: psychometric analyses of the Try To Quit Smoking instrument
L. Lundh, H. Alinaghizadeh, L. Törnkvist, H. Gilljam, M. Galanti

Collection of Nursing Open (2017).
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A secondary data analysis of Internet use in caregivers of persons with dementia
H. Kim, K. Rose, R. Netemeyer, E. Merwin, I. Williams

Collection of Nursing Open (2017).
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An integrative review of the characteristics of meaningful learning in healthcare professionals to enlighten educational practices in health care
L. Cadorin, A. Bagnasco, G. Rocco, L. Sasso

Collection of Nursing Open (2017).
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Test double blind
T. 172

Test blind review (2017).
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pH-Regulated Synthesis of Multi-Shelled Manganese Oxide Hollow Microspheres as Supercapacitor Electrodes Using Carbonaceous Microspheres as Templates
J. Wang, H. Tang, H. Ren, R. Yu, J. Qi, D. Mao, H. Zhao, D. Wang

Collection of Advanced Science (2017).

Abstract
Multi-shelled Mn2O3 hollow microspheres have been achieved through a pH-regulated method and used as supercapacitor electrodes. The designed unique architecture allows efficient use of pseudo-capacitive Mn2O3 nanomaterials for charge storage with facilitated transport for both ions and electrons, rendering them high specific capacitance, good rate capability, and remarkable cycling performance.
Abstract
Multi-shelled Mn2O3 hollow microspheres have been achieved through a pH-regulated method and used as supercapacitor electrodes. The designed unique architecture allows efficient [...]
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Advanced Science – Top Science with Maximum Accessibility
K. Severing

Collection of Advanced Science (2017).
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Electrode Nanostructures in Lithium-Based Batteries
N. Mahmood, Y. Hou

Collection of Advanced Science (2017).

Abstract
Lithium-based batteries possessing energy densities much higher than those of the conventional batteries belong to the most promising class of future energy devices. However, there are some fundamental issues related to their electrodes which are big roadblocks in their applications to electric vehicles (EVs). Nanochemistry has advantageous roles to overcome these problems by defining new nanostructures of electrode materials. This review article will highlight the challenges associated with these chemistries both to bring high performance and longevity upon considering the working principles of the various types of lithium-based (Li-ion, Li-air and Li-S) batteries. Further, the review discusses the advantages and challenges of nanomaterials in nanostructured electrodes of lithium-based batteries, concerns with lithium metal anode and the recent advancement in electrode nanostructures.
Abstract
Lithium-based batteries possessing energy densities much higher than those of the conventional batteries belong to the most promising class of future energy devices. However, [...]
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High-Volume Processed, ITO-Free Superstrates and Substrates for Roll-to-Roll Development of Organic Electronics
M. Hösel, D. Angmo, R. Søndergaard, G. Benatto, J. Carlé, M. Jørgensen, F. Krebs

Collection of Advanced Science (2017).

Abstract
The fabrication of substrates and superstrates prepared by scalable roll-to-roll methods is reviewed. The substrates and superstrates that act as the flexible carrier for the processing of functional organic electronic devices are an essential component, and proposals are made about how the general availability of various forms of these materials is needed to accelerate the development of the field of organic electronics. The initial development of the replacement of indium-tin-oxide (ITO) for the flexible carrier materials is described and a description of how roll-to-roll processing development led to simplification from an initially complex make-up to higher performing materials through a more simple process is also presented. This process intensification through process simplification is viewed as a central strategy for upscaling, increasing throughput, performance, and cost reduction.
Abstract
The fabrication of substrates and superstrates prepared by scalable roll-to-roll methods is reviewed. The substrates and superstrates that act as the flexible carrier for [...]
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The Rational Design of a Single-Component Photocatalyst for Gas-Phase CO2 Reduction Using Both UV and Visible Light
L. Hoch, T. Wood, P. O'Brien, K. Liao, L. Reyes, C. Mims, G. Ozin

Collection of Advanced Science (2017).

Abstract
The solar-to-chemical energy conversion of greenhouse gas CO2 into carbon-based fuels is a very important research challenge, with implications for both climate change and energy security. Herein, the key attributes of hydroxides and oxygen vacancies are experimentally identified in non-stoichiometric indium oxide nanoparticles, In2O3-x(OH)y, that function in concert to reduce CO2 to CO under simulated solar irradiation.
Abstract
The solar-to-chemical energy conversion of greenhouse gas CO2 into carbon-based fuels is a very important research challenge, with implications for both climate change and [...]
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Solar Fuels: The Rational Design of a Single-Component Photocatalyst for Gas-Phase CO2 Reduction Using Both UV and Visible Light (Adv. Sci. 1/2014)
L. Hoch, T. Wood, P. O'Brien, K. Liao, L. Reyes, C. Mims, G. Ozin

Collection of Advanced Science (2017).

Abstract
Advances towards the vision of the “solar fuels refinery” of the future are portrayed in the cover art, based on article 1400013 by G. A. Ozin and co-workers. In the article, the attributes of hydroxide groups and oxygen vacancies are identified for non-stoichiometric indium oxide photocatalytic nanoparticles in the light-assisted, gas-phase conversion of carbon dioxide to carbon monoxide. The ultimate goal of this work is to facilitate an energy transition from todays unsustainable “fossil fuel economy” to a new and sustainable “carbon dioxide economy”. The cover was designed by Chenxin Qian
Abstract
Advances towards the vision of the “solar fuels refinery” of the future are portrayed in the cover art, based on article 1400013 by G. A. Ozin and co-workers. In the article, [...]
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Biochar: a new promising catalyst support using methanation as a probe reaction
L. Zhu, S. Yin, Q. Yin, H. Wang, S. Wang, S. Myong, J. Park, S. Kwon

Energy Science & Engineering (2017).

Abstract
Biochar (BC), a by-product from the fast pyrolysis of rice husk, was activated by chemical and physical process. The activated biochar (ABC) showed graphite-like morphology and had a large amount of random pores with BET surface area of 1058 m2/g. The biochar properties observed by further characterization revealed its feasibility to be used as a catalyst support. Syngas methanation as a probe reaction was utilized to characterize biochar supported Ru catalyst. The catalytic performance of the Ru/ABC catalyst in methanation was superior or comparable to the conventional activated carbon (AC) supported Ru catalyst. A high CH4 selectivity of 98% and a CO conversion of 100% were obtained under the proper reaction conditions over the Ru/ABC catalyst.
Abstract
Biochar (BC), a by-product from the fast pyrolysis of rice husk, was activated by chemical and physical process. The activated biochar (ABC) showed graphite-like morphology [...]
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Inferior outdoor-exposed performances of encapsulated a-Si:H photovoltaic modules deposited with a high speed
S. Myong, J. Park, S. Kwon

Energy Science & Engineering (2017).

Abstract
We investigate the stabilized performance of encapsulated hydrogenated amorphous silicon photovoltaic modules depending on the deposition speed. The module products are degraded differently depending on the light-soaking environment. The modules deposited at a high speed demonstrate significant degradation in an outdoor exposure test, despite moderate degradation during indoor light soaking. However, the modules deposited at a low speed show a relatively more stable performance against the outdoor exposure test. Notably, some modules show the trend that a higher initial performance stimulates a higher light-induced degradation, leading to a lower performance in the outdoor environment.
Abstract
We investigate the stabilized performance of encapsulated hydrogenated amorphous silicon photovoltaic modules depending on the deposition speed. The module products are degraded [...]
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Effect of ester compounds on biogas production: beneficial or detrimental?
H. Yanti, R. Wikandari, R. Millati, C. Niklasson, M. Taherzadeh

Energy Science & Engineering (2017).

Abstract
Esters are major flavor compounds in fruits, which are produced in high volume. The widespread availability of these compounds in nature attracts interest on their behavior in anaerobic digestion in waste and wastewater treatments. The aim of this work was to study the effects of various esters at different concentrations in anaerobic digestion followed by determination of their minimum inhibitory concentration (MIC), and to study the effect of chain length of functional group and alkyl chain of ester on methane production. Addition of methyl butanoate, ethyl butanoate, ethyl hexanoate, and hexyl acetate at concentration up to 5 g L−1 increased methane production, while their higher concentrations inhibited the digestion process. The MIC values for these esters were between 5 and 20 g L−1. Except hexyl acetate, the esters at concentration 5 g L−1 could act as sole carbon source during digestion. For ethyl esters, increasing number of carbon in functional group decreased methane production. For acetate esters, alkyl chain longer than butyl inhibited methane production. Effect of ester on methane production is concentration-dependent.
Abstract
Esters are major flavor compounds in fruits, which are produced in high volume. The widespread availability of these compounds in nature attracts interest on their behavior [...]
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Evaluation of the economics of conversion to compressed natural gas for a municipal bus fleet
L. Yang, W. Tyner, K. Sarica

Energy Science & Engineering (2017).

Abstract
Domestic natural gas production has increased markedly in the United States, and now compressed natural gas (CNG) has the potential to become a cleaner and less expensive energy source than diesel fuel for use in the public transportation sector, especially for city bus fleets. This paper provides an economic analysis of possible CNG conversion for Lafayette, IN CityBus Corporation. It uses benefit–cost analysis to compare the total cost of three potential options for bus replacement: standard diesel, hybrid diesel-electric, and CNG. A spreadsheet model was used to estimate the total cost of these three fleet options over a 15-year project horizon. Results suggest that the CNG option has the lowest net present value (NPV) cost, and that cost savings would be larger if the corporation could obtain a grant for the CNG fueling station or if the project life span could expand to 20 years. From the environmental perspective, the CNG option would reduce greenhouse gas and particulate emissions particularly in comparison with the diesel option. Monte Carlo simulation was used to examine the inherent riskiness of the three fleet options. CNG is always lower cost than hybrid diesel-electric. Depending on assumptions regarding the underlying price distributions, the CNG option has a 51–100% chance of being lower cost than the standard diesel option.
Abstract
Domestic natural gas production has increased markedly in the United States, and now compressed natural gas (CNG) has the potential to become a cleaner and less expensive [...]
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A wavelet-nearest neighbor model for short-term load forecasting
G. Sudheer, A. Suseelatha

Energy Science & Engineering (2017).

Abstract
Load forecasts of short lead times ranging from an hour to a day ahead are essential for improving the economic efficiency and reliability of power systems. This paper proposes a hybrid model based on the wavelet transform (WT) and the weighted nearest neighbor (WNN) techniques to predict the day ahead electrical load. The WT is used to decompose the load series into deterministic series and fluctuation series that reflect the changing dynamics of data. The two subseries are then separately forecast using appropriately fitted WNN models. The final forecast is obtained by composing the predicted results of each subseries. The hourly electrical load of California and Spanish energy markets are taken as experimental data and the mean absolute percentage error (MAPE), Weekly MAPE (WMAPE) and Monthly MAPE (MMAPE) are computed to evaluate the forecasting performance of the next-day load forecasts. The forecasting efficiency of the proposed model is evaluated using db2, db4, db5 and bior 3.1 wavelets. The results demonstrate the forecasting accuracy of the proposed hybrid model.
Abstract
Load forecasts of short lead times ranging from an hour to a day ahead are essential for improving the economic efficiency and reliability of power systems. This paper proposes [...]
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An overview of proactive wind turbine control
A. Stotsky, B. Egardt, O. Carlson

Energy Science & Engineering (2017).

Abstract
Recent achievements in the proactive turbine control, based on the upwind speed measurements, are described in a unified framework (as an extension of the tutorial [1]), that in turn represents a systematic view of the control activity carried out within the Swedish Wind Power Technology Center (SWPTC). A new turbine control problem statement with constraints on blade loads is reviewed. This problem statement allows the design of a new class of simultaneous speed and pitch control strategies based on the preview measurements and look-ahead calculations. A generation of a piecewise constant desired pitch angle profile which is calculated using the turbine load prediction is reviewed in this article as one of the most promising approaches. This in turn allows the reduction of the pitch actuation and the design of the collective pitch control strategy with the maximum possible actuation rate. Two turbine speed control strategies based on one-mass and two-mass models of the drivetrain are also described in this article. The strategies are compared to the existing drivetrain controller. Moreover, postprocessing technique that can be used for estimation of the turbine parameters with improved performance is also discussed. Postprocessing-based estimation of the turbine inertia moment is given as an example. All the results are illustrated by simulations with a wind speed record from the Hönö turbine, located outside of Gothenburg, Sweden.
Abstract
Recent achievements in the proactive turbine control, based on the upwind speed measurements, are described in a unified framework (as an extension of the tutorial [1]), that [...]
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Blade root moment sensor failure detection based on multibeam LIDAR for fault-tolerant individual pitch control of wind turbines
A. Stotsky

Energy Science & Engineering (2017).

Abstract
Detection of blade root moment sensor failures is an important problem for fault-tolerant individual pitch control, which plays a key role in reduction of uneven blade loads of large wind turbines. A new method for detection of blade root moment sensor failures which is based on variations induced by a vertical wind shear is described in this paper. The detection is associated with monitoring of statistical properties of the difference between amplitudes of the first harmonic of the blade load, which is calculated in two different ways. The first method is based on processing of the load sensor signal, which contains a number of harmonics. The first harmonic is recovered via least squares estimation of the blade load signal with harmonic regressor and strictly diagonally dominant (SDD) information matrix. The second method is a model-based method of estimation of the first harmonic, which relies on the blade load model and upwind speed measurements provided by multibeam Light Detection and Ranging (LIDAR). This is a new application for future LIDAR-enabled wind turbine technologies. Moreover, adaptation of the load model in a uniform wind field is proposed. This adaptation improves accuracy of the load estimation and hence the performance of the blade load sensor failure detection method.
Abstract
Detection of blade root moment sensor failures is an important problem for fault-tolerant individual pitch control, which plays a key role in reduction of uneven blade loads [...]
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Investigating residual trapping in CO2 storage in saline aquifers – application of a 2D glass model, and image analysis
M. Soroush, D. Wessel-Berg, O. Torsaeter, J. Kleppe

Energy Science & Engineering (2017).

Abstract
Two-dimensional glass model experiments are used to investigate the residual trapping mechanism of CO2 stored in saline aquifers. For this purpose, two proxy fluids are chosen to simulate the CO2-brine behavior under reservoir conditions. The first set of experiments is carried out by flooding n-heptane in a mixture of glycerol and water inside a glass bead porous media. Fluids and porous materials are designed so that the dimensionless groups are in the range of real storage sites. Another set of proxy fluid consists of dodecane and a different mixture of glycerol and water, representing the second wettability condition for the system. The size of the glass beads chosen was fine (70–110 μm) in order to investigate residual trapping phenomena. For each set, after complete drainage process, an imbibition process is performed and in each time step, images are taken from the phenomena. The images are processed using a red, green, blue (RGB) color concept using a Matlab code that was developed for this study. By using this process, it is possible to measure the residual trapping of CO2 proxy fluid for each test and to determine the saturation profile in the model. Tests are carried out at various imbibition and drainage rates to study the effect of the rate on the results. Fine-scale numerical simulation models are constructed for comparison with experimental results. Good agreement is obtained between the simulation results and the image processing estimations, as well as the readings from the material balances during the experiments. This study could provide a framework for modeling different reservoir conditions for residual trapping mechanism and the impact of different parameters in future studies.
Abstract
Two-dimensional glass model experiments are used to investigate the residual trapping mechanism of CO2 stored in saline aquifers. For this purpose, two proxy fluids are chosen [...]
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Practical evaluation of organic polymer thermoelectrics by large-area R2R processing on flexible substrates
R. Søndergaard, M. Hösel, N. Espinosa, M. Jørgensen, F. Krebs

Energy Science & Engineering (2017).

Abstract
Here, we present a process based on roll-to-roll (R2R) technology which allows for very fast processing of polymer thermoelectric (TE) devices and we furthermore demonstrate a simplified but more efficient way of serially connecting these devices by means of R2R thin-film processing. The new device architecture makes it possible to use only one TE material (opposed to two materials which are employed in well-known Peltier elements), and a total of 18, 000 serially connected junctions were prepared by flexoprinting of silver electrodes and by rotary screen printing of poly(3, 4-ethylenedioxythiophene) (PEDOT):polystyrene sulfonate (PSS) as the TE material. Testing of devices revealed that the new architecture clearly showed to be functioning as expected, but also pointed toward challenges for thin-film TE development which is the influence of the substrate thickness on the thermal gradient over a device and the currently low performance available. A life-cycle assessment (LCA) was carried out in order to evaluate the sustainability of the new architecture and to estimate the requirements for development of a successful technology.
Abstract
Here, we present a process based on roll-to-roll (R2R) technology which allows for very fast processing of polymer thermoelectric (TE) devices and we furthermore demonstrate [...]
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Study of demagnetization risk for a 12 kW direct driven permanent magnet synchronous generator for wind power
S. Sjökvist, S. Eriksson

Energy Science & Engineering (2017).

Abstract
One of the main aspects when designing a permanent magnet (PM) generator is to choose suitable PMs, both in terms of achieving the required flux in the generator but also of withstanding high demagnetizing fields, that is, having sufficiently high coercivity. If the coercivity is too low, the magnets are at risk of demagnetizing, fully or partially, at the event of a short circuit and/or an increase in temperature. This study aims to determine the risk of demagnetization for a 12 kW direct driven permanent magnet synchronous generator. Furthermore, as the prices on PMs have increased drastically the last few years the possibility to use smaller and/or cheaper PMs of different grades has been investigated. A new proprietary finite element method (FEM) model has been developed, which is also presented. The study is based on simulations from this FEM model and is focused on NdFeB magnets. Results show that the reference magnet can withstand a two-phase short circuit at both the temperatures tested and in both geometries. The use of cheaper magnets, smaller air gap and in the event of a two-phase short circuit often results in partial irreversible demagnetization. However, magnets with lower coercivity are easier demagnetized.
Abstract
One of the main aspects when designing a permanent magnet (PM) generator is to choose suitable PMs, both in terms of achieving the required flux in the generator but also [...]
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Why the molten salt fast reactor (MSFR) is the “best” Gen IV reactor
D. Siemer

Energy Science & Engineering (2017).

Abstract
A simultaneously “nuclear”, permanent, and in-time solution to mankinds energy-related problems would require the relatively rapid manufacture of 10, 000–30, 000 genuinely sustainable, full-sized (~1 GWe) reactors. This “nuclear renaissance” would have to be implemented with breeder reactors because todays commercial nuclear fuel cycle is unsustainable and based upon a fuel (235U) that is intrinsically expensive and politically problematic. The purpose of this paper is to point out why a simple/cheap “minimal reprocessing” implementation of the European Unions (EUs) molten salt fast reactor (MSFR) concept represents the most promising way to implement that technical fix: Its primary drawback is that it would require virtually everyone currently involved with managing, researching, implementing, regulating, or “helping” the USAs nuclear power industry to embrace a massive paradigm shift.
Abstract
A simultaneously “nuclear”, permanent, and in-time solution to mankinds energy-related problems would require the relatively rapid manufacture of 10, 000–30, 000 genuinely [...]
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Conducting polymer-based flexible supercapacitor
I. Shown, A. Ganguly, L. Chen, K. Chen

Energy Science & Engineering (2017).

Abstract
Flexible supercapacitors, a state-of-the-art material, have emerged with the potential to enable major advances in for cutting-edge electronic applications. Flexible supercapacitors are governed by the fundamentals standard for the conventional capacitors but provide high flexibility, high charge storage and low resistance of electro active materials to achieve high capacitance performance. Conducting polymers (CPs) are among the most potential pseudocapacitor materials for the foundation of flexible supercapacitors, motivating the existing energy storage devices toward the future advanced flexible electronic applications due to their high redox active-specific capacitance and inherent elastic polymeric nature. This review focuses on different types of CPs-based supercapacitor, the relevant fabrication methods and designing concepts. It describes recent developments and remaining challenges in this field, and its impact on the future direction of flexible supercapacitor materials and relevant device fabrications.
Abstract
Flexible supercapacitors, a state-of-the-art material, have emerged with the potential to enable major advances in for cutting-edge electronic applications. Flexible supercapacitors [...]
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Pilot-scale processing with alkaline pulping and enzymatic saccharification for bioethanol production from rice straw
M. Sekine, Y. Ogawa, N. Matsuoka, Y. Izumi

Energy Science & Engineering (2017).

Abstract
We examined pilot-scale bioethanol production from rice straw using sodium carbonate pulping as the alkaline pulping method and enzymatic saccharification. The yield of prewashed rice straw after the crushing and prewashing stage decreased with an increase in the input in rice straw. The pulp yield after alkaline cooking was 66–68% at kappa number ranging from 32 to 36, which was comparatively higher than the laboratory-scale study. The yield of enzymatic saccharized glucose was decreased with the increase in washed pulp and its saccharification rate was approximately 20%. We successfully produced approximately 100 liters of 95% ethanol from 1000 Bone-Dry kg (BDkg) rice straw. The results of our pilot-scale study indicated that the relationship between resource input and product yield for each operation exhibited exponential or logarithmic curves, rather than linear decreases or increases, which could suggest a high-cost structure for bioethanol production when the resource input is larger. However, we established an optimum quantity of resource input, approximately 2000–3000 BDkg in our pilot-scale study, for higher efficiencies.
Abstract
We examined pilot-scale bioethanol production from rice straw using sodium carbonate pulping as the alkaline pulping method and enzymatic saccharification. The yield of prewashed [...]
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Nuclear fusion as a massive, clean, and inexhaustible energy source for the second half of the century: brief history, status, and perspective
J. Sánchez

Energy Science & Engineering (2017).

Abstract
Fusion energy, based on the use of broadly available inexhaustible resources as lithium and deuterium and with minimal impact to the environment, aims at a change in the energy supply paradigm: instead of its current dependence on natural resources and environmental impact, energy would become a technology-dependent resource with unlimited adaptive availability and whose unit cost should decrease as technology progresses. This article intends to give a picture of where fusion research stands today and the perspectives: the achievements, the difficulties, the current status, marked by the construction of the ITER experiment which will demonstrate the scientific feasibility of fusion power, and the perspectives toward the first demonstration power plant, DEMO, which, according to the European Roadmap, could start the construction shortly after the full power experiments in ITER (
Abstract
Fusion energy, based on the use of broadly available inexhaustible resources as lithium and deuterium and with minimal impact to the environment, aims at a change in the energy [...]
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Combined solar heat and power with microgrid storage and layered smartgrid control toward supplying off-grid rural villages
G. Prinsloo, R. Dobson

Energy Science & Engineering (2017).

Abstract
A project has been initiated in South Africa to design, model, build, and evaluate an easy to install solar fueled combined heat and power (micro-CHP) system to supply off-grid rural villages and eco-estate communities. This study describes the design of a model that offers a combined 3 kW peak electrical, 12 kW peak thermal, stand-alone solar power technology solution with microgrid storage to deliver power, and heat when the sun is shining and after sunset (at night time). The CHP demand side management system manages power and heat distribution to individual households in a small rural village based on a proposed smart microgrid technology solution. The solution aims to balance the heat/power demand side requirements based on digital feedback on heat/power utilization patterns and user demand. Aspects of the micro-CHP system microgrid control are discussed while a modular smartgrid solution is selected for smart microgrid applications.
Abstract
A project has been initiated in South Africa to design, model, build, and evaluate an easy to install solar fueled combined heat and power (micro-CHP) system to supply off-grid [...]
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Cost modeling of lithium-ion battery cells for automotive applications
G. Patry, A. Romagny, S. Martinet, D. Froelich

Energy Science & Engineering (2017).

Abstract
The purpose of this study was to highlight the technical and economic issues arising in lithium-ion cells for automotive applications, and to indicate some potential solutions to lower the cost. This topic has already been the subject of some studies, but, although of primary importance, the role on cost of a cell design parameter, the electrode coating thickness, has rarely been described. This study intends to explore particularly the influence of this parameter. To do so, the cost of cells with four positive electrode materials (NMC, NCA, LFP, and LMO), and the same negative electrode material are compared at several electrode thickness. The cost of these cells is computed using an innovative model and varies between 230 and 400 $ per kWh. With the assumptions used, it appears that the potential savings resulting from doubling the electrode coating thickness from 50 to 100 μm at a given porosity represent roughly 25% of the cell cost. The electrode coating thickness emerges as an essential parameter for an unbiased cells cost comparison. This article gives a view of the current lithium-ion cells costs, and provides guidelines to lower cells cost.
Abstract
The purpose of this study was to highlight the technical and economic issues arising in lithium-ion cells for automotive applications, and to indicate some potential solutions [...]
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Assessment of the minimum value of photovoltaic electricity in Italy
M. Pagliaro, F. Meneguzzo, F. Zabini, R. Ciriminna

Energy Science & Engineering (2017).

Abstract
We investigate the value of solar photovoltaic (PV) power in the Italian wholesale electricity market (IPEX). A model is developed and applied to simulate and predict the monthly average electricity prices in peak hours, as well as to simulate scenarios without PV generation. The computed merit-order effect of the PV generation in Italy, around −2.9 €/MWh per each additional GWh of PV production, as well as the greater −4.5 €/MWh absolute value evaluated under the hypothesis of stationary electricity demand, are in line with the upper values found in related studies of near mature renewable energy markets. A strong relationship of the value of PV electricity in the IPEX with the electricity demand is clearly evident, leading to important policy implications in terms of possible actions on the granted subsidies, electrification of energy end use, and promotion of specific PV technologies. The anomalous temporal behavior of the IPEX, shown by high off-peak electricity prices that followed the installation of Italys large PV park, partly offsets the beneficial effect of PV generation.
Abstract
We investigate the value of solar photovoltaic (PV) power in the Italian wholesale electricity market (IPEX). A model is developed and applied to simulate and predict the [...]
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Solar power in Quebec: a unique potential soon to be fulfilled
M. Pagliaro

Energy Science & Engineering (2017).

Abstract
Quebecs large solar power potential markedly contrasts with its poor achievements in using solar energy in this large and wealthy region of the world. Reviewing recent developments and putting discussion in the socioeconomic context, we provide arguments that justify our viewpoint that solar energy will soon be a relevant source of power in this Province of Canada. The rapid fall in price of both main solar power technologies, photovoltaics, and solar thermal, along with significant levels of insolation and the pronounced environmental awareness of Quebecs population support the conclusions of this study.
Abstract
Quebecs large solar power potential markedly contrasts with its poor achievements in using solar energy in this large and wealthy region of the world. Reviewing recent developments [...]
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A simulation study of a bioethanol-solar-reforming system for proton-exchange membrane fuel cell home cogeneration system
S. Obara

Energy Science & Engineering (2017).

Abstract
The energy supply characteristic of a proton-exchange membrane fuel cell for houses is strongly influenced in a hydrogen supply unit. Therefore, a bioethanol reforming system (FBSR) with a sunlight heat source is developed as a potential fuel supply system for distributed fuel cells. However, the temperature distribution of a catalyst layer in the reactor is not stable under conditions of unstable solar radiation and unstable outside air temperature, as a result, it is thought that the inversion ratio (the percentage of hydrogen obtained from ethanol) of a reforming reaction will decrease. In this paper, heat transmission analysis was used in the catalyst layer of the reformer of FBSR, and the fundamental performance of FBSR was investigated. Fluctuations of the solar insolation over a short period of time affect the hydrogen-generating rate of FBSR. Moreover, the amount of hydrogen production of FBSR was simulated using meteorological data from a day in March and a day in August in a cold region (Sapporo in Japan). In this research, the relation between the collected area of a solar collector and the energy supply to an individual house was obtained.
Abstract
The energy supply characteristic of a proton-exchange membrane fuel cell for houses is strongly influenced in a hydrogen supply unit. Therefore, a bioethanol reforming system [...]
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Testing of the Katrix rotary lobe expander for distributed concentrating solar combined heat and power systems
Z. Norwood, D. Kammen, R. Dibble

Energy Science & Engineering (2017).

Abstract
In this article, we present performance results and analysis of a novel rotary lobe expander device. This is part of a larger research effort into the analysis and design of a small-scale solar system that would compete with available distributed technologies for heat and electricity generation. To choose an appropriate working fluid and components for a distributed concentrating solar combined heat and power (DCS-CHP) system, we compared many different working fluids, collectors, and expander choices. Of the expanders analyzed, including piston expanders, radial inflow turbines, Tesla turbines, screw expanders, and scroll expanders, the rotary lobe expander shows the greatest promise in small-scale power applications due to its high efficiency in expanding fluids over large pressure ratios and its low cost to manufacture. This article focuses on testing of a prototype small-scale expander that was chosen because, to date, no suitable commercial product of less than 10 kW has been found for this application. Initial testing was completed with air to get results that should be indicative of future testing with steam. The test system consists of a compressed air expander (a prototype designed by Katrix, Inc. of Australia) connected to an induction motor driven by a variable frequency drive (VFD) that enables expander testing at varying shaft speeds. Results of the expander testing are reported isentropic efficiencies of 22–25%, thermomechanical efficiencies of 80–95%, and pressure ratios of 6–11 at the tested speeds. Despite mixed results from this particular expander, future refinements could lead to a new class of expanders with low cost and high performance for use in solar combined heat and power and waste-heat recovery.
Abstract
In this article, we present performance results and analysis of a novel rotary lobe expander device. This is part of a larger research effort into the analysis and design [...]
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Comparing oxidative and dilute acid wet explosion pretreatment of Cocksfoot grass at high dry matter concentration for cellulosic ethanol production
S. Njoku, H. Uellendahl, B. Ahring

Energy Science & Engineering (2017).

Abstract
The choice of a suitable pretreatment method and the adjustment of the pretreatment parameters for efficient conversion of biomass are crucial for a successful biorefinery concept. In this study, cocksfoot grass, a suitable lignocellulosic biomass with a potential for large-scale production was investigated for cellulosic ethanol production. The biomass raw materials were pretreated using wet explosion (WEx) at 25% dry matter concentration with addition of oxygen or dilute sulfuric acid. The enzymatic hydrolysis of cellulose was significantly improved after pretreatment. The highest conversion into cellulose monomeric C6 sugars was achieved for WEx condition AC-E (180°C, 15 min, and 0.2% sulfuric acid). For that condition, the highest ethanol yield of 197 g/kg DM (97% of theoretical maximum value) was achieved for SSF process by Saccharomyces cerevisiae. However, the highest concentration of hemicellulose C5 sugars was found for WEx pretreatment condition O2-A (160°C, 15 min, and 6 bar O2) which means that the highest potential ethanol yield was found at this moderate pretreatment condition with oxygen added. Increasing the pretreatment temperature to 180–190°C with addition of oxygen or dilute sulfuric acid significantly degrades the solubilized hemicellulose sugars and thus, achieved the highest formation of by-products.
Abstract
The choice of a suitable pretreatment method and the adjustment of the pretreatment parameters for efficient conversion of biomass are crucial for a successful biorefinery [...]
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Butanol and ethanol production from lignocellulosic feedstock: biomass pretreatment and bioconversion
S. Nanda, A. Dalai, J. Kozinski

Energy Science & Engineering (2017).

Abstract
Lignocellulosic feedstock has tremendous potential to sustain the renewable production of biofuels such as ethanol and butanol. Although lignocellulosic biomass is a storehouse of energy in the form of cellulose and hemicellulose, yet lignin acts as a barrier against their hydrolysis. A dilute acid pretreatment disintegrates the biomass complex and allows cellulolytic enzymes to hydrolyze cellulose and hemicelluloses in releasing fermentable sugars. The current study investigates the effect of different H2SO4 doses (0–2.5%) on the three lignocellulosic feedstock material, especially pinewood, timothy grass, and wheat straw at 121°C for 1 h. Furthermore, the pretreated feedstock was subjected to enzymatic hydrolysis using cellulase, β-glucosidase, and xylanase at 45°C for 72 h. The biomass hydrolysates containing monomeric sugars (glucose and xylose) were fermented using Saccharomyces cerevisiae and Clostridium beijerinckii for ethanol and butanol production, respectively. A comparative evaluation for the concentrations of ethanol and butanol, residual sugars as well as byproducts such as acetone, acetate, and butyrate from biomass hydrolysates was performed. Pinewood hydrolysate revealed high ethanol (24.1 g/L) and butanol (11.6 g/L) concentrations due to greater sugar content. In contrast to ethanol fermentation by S. cerevisiae, butanol fermentation by C. beijerinckii demonstrated low butanol levels in the hydrolysates due to butanol toxicity toward clostridia.
Abstract
Lignocellulosic feedstock has tremendous potential to sustain the renewable production of biofuels such as ethanol and butanol. Although lignocellulosic biomass is a storehouse [...]
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Coevaporated calcium-silver metal alloys as contact for highly transparent organic solar cells
J. Meiss, H. Ziehlke, S. Schubert, K. Leo, M. Riede

Energy Science & Engineering (2017).

Abstract
We present 10-nm thick metal alloys created by coevaporation of calcium and silver as transparent top electrode for inverted bulk heterojunction small-molecule organic solar cells (SMOSC). It is shown that such alloys exhibit sufficiently high conductivity to replace previously used thicker (>14 nm) pure Ag contacts. At the same time, Ca:Ag alloys have higher transmittance compared to pure Ag, which is desirable for semitransparent SMOSC where the light passes through the device and the metal contact. We find that a metal contact consisting of 1 nm Ag underlayer and 10 nm Ca:Ag of 1:1 mixing ratio (total Ag content by volume of 6 nm) on glass has an average transmittance in the visible range of 76% with a sheet resistance of 27.1 Ω/□, approaching the performance of ITO while being applied by a much gentler deposition method. Application of 10-nm thick alloys in semitransparent SMOSC lead to transmittance in the visible range Tvis of up to 49% and efficiency η of up to 2.3%, showing superior performance compared to devices with pure Ag top contacts.
Abstract
We present 10-nm thick metal alloys created by coevaporation of calcium and silver as transparent top electrode for inverted bulk heterojunction small-molecule organic solar [...]
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Dynamic modeling of a small open Joule cycle reciprocating Ericsson engine: simulation results
F. Lontsi, O. Hamandjoda, K. Djanna, P. Stouffs, J. Nganhou

Energy Science & Engineering (2017).

Abstract
Externally heated Joule cycle reciprocating engines, also known as Ericsson engines, are particularly suitable for small-scale solar energy conversion and microcogeneration using biomass or gas effluents at high temperatures. These types of engine have been developed in the context of the current issue of climate change, combined with a progressive depletion of fossil fuels. A dynamic model of a 1.67 kW small open Joule cycle engine has been developed in order to study operational stability and behavioral control, especially during transient phases. Models are implemented on a Matlab/Simulink platform where simulations of the dynamics of engine start-up and steady conditions are carried out. The optimal settings of valves and the key engine parameters have also been determined. Simulation results reveal a rapid transient phase. Hot starting is achieved in about 5.3 sec and the system is stabilized, with a thermal efficiency of approximately 29%. The system responds well when subjected to selected perturbations.
Abstract
Externally heated Joule cycle reciprocating engines, also known as Ericsson engines, are particularly suitable for small-scale solar energy conversion and microcogeneration [...]
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An A-CAES pilot installation in the distribution system: A technical study for RES integration
P. Lombardi, C. Röhrig, K. Rudion, R. Marquardt, M. Müller-Mienack, A. Estermann, Z. Styczynski, N. Voropai

Energy Science & Engineering (2017).

Abstract
In the last decade in Europe, the power generated by Renewable Energy Sources (RES) has significantly increased. For the electric power system, the integration of a high amount of power generated by RES represents a big challenge. Energy Storage Systems (ESS) may help to solve problems related to the grid integration of RES. In this study, an analysis of the benefits that a planned and dedicated Adiabatic Compressed Air Energy Storage (A-CAES) system may provide to a distribution network with a high penetration of RES will be carried out. The A-CAES system, taken into account in this investigation, is based on the proposed German study so-called “ADELE project”. The technical benefits as well as the corresponding costs that A-CAES brings to the system which were analyzed using the load and RES generation time series for 2010 and 2020, and were based on technical data from a selected part of a German distribution power network, were evaluated and results of those broad investigations are presented in this study. The result of the investigations shows that the direct technical benefits are quite limited for the A-CAES technology as it exists today.
Abstract
In the last decade in Europe, the power generated by Renewable Energy Sources (RES) has significantly increased. For the electric power system, the integration of a high amount [...]
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Steady-state and transient voltage stability analysis of a weak distribution system with a remote doubly fed induction generator-based wind farm
A. Kunwar, R. Bansal, O. Krause

Energy Science & Engineering (2017).

Abstract
In modern, stressed distribution system, voltage stability is a major concern from planning and operation perspectives. Remote wind farm connected to a weak distribution system through a long line could adversely affect the voltage stability of the respective distribution network. This paper investigates the transient and steady-state voltage issues of a distribution network with a distant doubly fed induction generator (DFIG)-based wind farm. Results show that a distant DFIG-based wind farm could improve the voltage stability of a distribution network with a large motor load in steady-state operating condition as well as following disturbances, like three-phase faults, sudden load tripping, and motor starting.
Abstract
In modern, stressed distribution system, voltage stability is a major concern from planning and operation perspectives. Remote wind farm connected to a weak distribution system [...]
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Engineering evaluation of direct methane to methanol conversion
A. Klerk

Energy Science & Engineering (2017).

Abstract
Investigations into direct methane to methanol conversion are justified based on the avoidance of synthesis gas generation, which accounts for around 60% of the capital cost of synthesis gas to methanol conversion. A significant body of information already exists on the process chemistry, but little has been reported on the engineering of such a process. An engineering evaluation of the process was performed and the potential of this process as a platform technology for small-scale gas-to-liquids (GTL) applications was evaluated. It was found that direct methane to methanol conversion had 35% carbon efficiency and 28% thermal efficiency, which were about half of the process efficiencies of indirect methanol synthesis using synthesis gas. The poor process efficiency was mainly a consequence of the irreversible loss of carbon to CO x during conversion. The direct methane to methanol process also required an air separation unit, which eroded the stated benefit of avoiding a synthesis gas generation step in the process. The utility footprint was typical of GTL processes, with large gas compression duties and cooling duties. Overall, the engineering evaluation indicated there was no benefit to employ direct methane to methanol conversion instead of indirect methanol synthesis (the industry standard), and there was no specific benefit of direct methane to methanol conversion, irrespective of scale, for GTL applications.
Abstract
Investigations into direct methane to methanol conversion are justified based on the avoidance of synthesis gas generation, which accounts for around 60% of the capital cost [...]
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Esterification of hydrolyzed sea mango (Cerbera odollam) oil using various cationic ion exchange resins
J. Kansedo, K. Lee

Energy Science & Engineering (2017).

Abstract
This study investigates the esterification of hydrolyzed sea mango (Cerbera odollam) oil using several cationic ion exchange resins. The best resins were selected based on their performance in a preliminary esterification process. The best resins were then subsequently used in the optimization of the process parameters. The esterification parameters studied were reaction temperature (40–160°C), reaction time (0–5 h), molar ratio of oil to methanol (0.5:1 to 1:14), and catalyst loading (1–14 wt%). Among the resins studied, Amberlyst 15 was found to be the most promising catalyst in the esterification of the hydrolyzed sea mango oil. Moderate reaction temperatures, 60–100°C, were found to be adequate in converting the hydrolyzed sea mango oil into esters. Further investigation revealed that the esterification reaction using the cationic ion exchange resins proceeds at a fast rate, whereby fatty acid methyl esters (FAME) yield of over 80% at moderate reaction temperature was achievable in less than 1 h of reaction time. Small amount of catalyst, which is less than 5 wt%, was also found to be sufficient in catalyzing the esterification process to an acceptable yield.
Abstract
This study investigates the esterification of hydrolyzed sea mango (Cerbera odollam) oil using several cationic ion exchange resins. The best resins were selected based on [...]
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Discovering new energy solutions
T. Kåberger

Energy Science & Engineering (2017).
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Numerical investigation of the effects of dwell time duration in a two-stage injection scheme on exergy terms in an IDI diesel engine by three-dimensional modeling
S. Jafarmadar, A. Zehni

Energy Science & Engineering (2017).

Abstract
Dwell duration of multiple-injection scheme is an important parameter, which makes it possible to shift the tradeoff curve between soot and NOx closer to the origin. In this investigation, therefore, energy and exergy analyses are carried out for various two-step injection schemes in which 25% of the total fuel is injected during the second pulse and the dwell time is increased from 5°CA (crank angle) to 30°CA by 5°CA increments. The calculations are performed for a Lister 8.1 indirect injection (IDI) diesel engine at full load operation. The energy analysis for these schemes is performed during a closed cycle by using a three-dimensional CFD code. The cylinder pressure results for the baseline engine are compared with the corresponding experimental data and they show good agreement. For the exergy analysis, an in-house computational code has been developed, which uses the results of energy analysis in various cases. With crank angle positions and dwell durations set for different injection schemes, various rates of exergy are calculated and the cumulative exergy components are identified separately. The results show that the values of work exergy and exergy efficiency decrease when the dwell duration is changed from 5°CA to 30°CA. Also, there is a sharp change in the exergy parameters when the dwell time reaches 25°CA.
Abstract
Dwell duration of multiple-injection scheme is an important parameter, which makes it possible to shift the tradeoff curve between soot and NOx closer to the origin. In this [...]
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A bridge to nowhere: methane emissions and the greenhouse gas footprint of natural gas
R. Howarth

Energy Science & Engineering (2017).

Abstract
In April 2011, we published the first peer-reviewed analysis of the greenhouse gas footprint (GHG) of shale gas, concluding that the climate impact of shale gas may be worse than that of other fossil fuels such as coal and oil because of methane emissions. We noted the poor quality of publicly available data to support our analysis and called for further research. Our paper spurred a large increase in research and analysis, including several new studies that have better measured methane emissions from natural gas systems. Here, I review this new research in the context of our 2011 paper and the fifth assessment from the Intergovernmental Panel on Climate Change released in 2013. The best data available now indicate that our estimates of methane emission from both shale gas and conventional natural gas were relatively robust. Using these new, best available data and a 20-year time period for comparing the warming potential of methane to carbon dioxide, the conclusion stands that both shale gas and conventional natural gas have a larger GHG than do coal or oil, for any possible use of natural gas and particularly for the primary uses of residential and commercial heating. The 20-year time period is appropriate because of the urgent need to reduce methane emissions over the coming 15–35 years.
Abstract
In April 2011, we published the first peer-reviewed analysis of the greenhouse gas footprint (GHG) of shale gas, concluding that the climate impact of shale gas may be worse [...]
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Turbine design and field development concepts for tidal, ocean, and river applications
D. Zeiner-Gundersen

Energy Science & Engineering (2017).

Abstract
This paper discusses tidal, ocean, and river free turbine functional design parameters and general considerations associated with tidal field developments. A particular focus is on the importance of considering mechanical fatigue and the associated calculation method when designing a turbine for the challenging hydrodynamic environment. The balance between high-fatigue resistances, costs associated with designing components, and potential for reduced turbine efficiency is discussed in regards to the potential energy extracted from a field site. A novel flexible foil vertical turbine concept with high-fatigue resistance, and simple installation and retrieval methods is shown to have a low kWh cost per production output compared to other hydrodynamic turbine concepts. Three possible field development concepts for the flexible foil turbine are described herein for river, ocean current, and tidal applications.
Abstract
This paper discusses tidal, ocean, and river free turbine functional design parameters and general considerations associated with tidal field developments. A particular focus [...]
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Effect of oxomolybdate species dispersion on direct methanol oxidation to dimethoxymethane over MoO x /TiO2 catalysts
J. Faye, M. Capron, A. Takahashi, S. Paul, B. Katryniok, T. Fujitani, F. Dumeignil

Energy Science & Engineering (2017).

Abstract
The one-step selective oxidation of methanol to dimethoxymethane (DMM) was demonstrated over titania-supported molybdenum oxide catalysts, containing different amounts of molybdenum and prepared using two different impregnation techniques, namely wet impregnation and incipient wetness impregnation. The corresponding catalysts exhibited both acidic and redox properties, which are necessary for the oxidation of methanol to formaldehyde with subsequent condensation of the latter with excess methanol to finally yield DMM. The formation of well-dispersed polyoxomolybdate species on the catalyst surface was evidenced using IR-Raman, X-ray diffraction, and nitrogen physisorption. Varying the amount of these polyoxomolydate species was associated with a modulation of the acidic and redox properties, as shown by NH3-TPD and H2-TPR. With respect to the catalytic performances, the best balance between acid and redox properties was observed over the samples containing 8 wt.% Mo, which corresponds to a theoretical MoO x species coverage close to a monolayer.
Abstract
The one-step selective oxidation of methanol to dimethoxymethane (DMM) was demonstrated over titania-supported molybdenum oxide catalysts, containing different amounts of [...]
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Optimization and comparison analysis for application of PV panels in three villages
M. Fadaeenejad, M. Radzi, M. Fadaeenejad, M. Zarif, Z. Gandomi

Energy Science & Engineering (2017).

Abstract
In recent years, research about the application and optimization of PV panels has grown rapidly. Especially for stand-alone solar systems there have been some problems related to first stages of design and application. Finding the optimum slope of PV panels in order to maximize the absorbed solar radiation is considered as one of the major obstacles. Although in Malaysia there have been some research works about finding of optimal tilt angle, however, this research work aims to start investigation about slope of PV panels for three villages without electricity and prior research. The Liu and Jordan model is applied to find the monthly optimal tilt angle and fixed tilt angle for the application of solar energy in these rural locations. The results demonstrate that the optimal tilt angle in these locations is less than 5°.
Abstract
In recent years, research about the application and optimization of PV panels has grown rapidly. Especially for stand-alone solar systems there have been some problems related [...]
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Oxyfuel combustion in rotary kiln lime production
M. Eriksson, B. Hökfors, R. Backman

Energy Science & Engineering (2017).

Abstract
The purpose of this article is to study the impact of oxyfuel combustion applied to a rotary kiln producing lime. Aspects of interest are product quality, energy efficiency, stack gas composition, carbon dioxide emissions, and possible benefits related to carbon dioxide capture. The method used is based on multicomponent chemical equilibrium calculations to predict process conditions. A generic model of a rotary kiln for lime production was validated against operational data and literature. This predicting simulation tool is used to calculate chemical compositions for different recirculation cases. The results show that an oxyfuel process could produce a high-quality lime product. The new process would operate at a lower specific energy consumption thus having also a reduced specific carbon dioxide emission per ton of product ratio. Through some processing, the stack gas from the new process could be suitable for carbon dioxide transport and storage or utilization. The main conclusion of this paper is that lime production with an oxyfuel process is feasible but still needs further study.
Abstract
The purpose of this article is to study the impact of oxyfuel combustion applied to a rotary kiln producing lime. Aspects of interest are product quality, energy efficiency, [...]
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Tip speed ratio control of a 200 kW VAWT with synchronous generator and variable DC voltage
S. Eriksson, J. Kjellin, H. Bernhoff

Energy Science & Engineering (2017).

Abstract
A novel control method for a fixed-pitch variable speed wind turbine is introduced and experimental results are presented. The measured absorbed power and rotational speed, together with a look-up table for the aerodynamic efficiency, are used to estimate the wind speed reaching the turbine as well as the tip speed ratio. Thereby, the control is independent on wind speed measurements and the wind turbine itself is used as an anemometer. Tip speed ratio control is implemented by comparing the estimated tip speed ratio to a reference value and adjusting the DC voltage level accordingly. Tip speed ratio control benefits from that the aerodynamic efficiency hardly varies with changing tip speed ratio when close to its optimum value. Experimental results from a 200 kW vertical axis wind turbine are presented. The voltage from the permanent magnet generator is passively rectified and the alternating DC voltage is then inverted, filtered, transformed, and grid connected. The estimated wind speed is compared with the measured wind speed. The absorbed power when tip speed ratio control has been implemented is shown. It is concluded that the presented control method works and some future improvements are discussed.
Abstract
A novel control method for a fixed-pitch variable speed wind turbine is introduced and experimental results are presented. The measured absorbed power and rotational speed, [...]
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Experimental study of the effect of inhibitors in wax precipitation by different techniques
B. Coto, C. Martos, J. Espada, M. Robustillo, J. Peña

Energy Science & Engineering (2017).

Abstract
The blocking problems in equipment and flowlines caused by precipitation of wax solids is a well-known problem and large research efforts have been focused on developing procedures dealing with wax deposition. Among the different alternatives, the use of chemicals is frequently used to inhibit wax precipitation. The presence of these compounds modifies the size and/or the shape of the paraffinic solids, thus affecting their flow behavior and cold properties. In this work, a methodology based on different experimental techniques was developed to study the effect of different additives on the crude oil behavior at low temperature. Four commercial inhibitors were added to three crude oils in different concentrations. The effect of the inhibitors on wax precipitation was studied using differential scanning calorimetry (DSC) and cross-polarized microscopy (CPM). Obtained results for wax appearance temperature (WAT) using DSC do not show remarkable differences regarding the presence of inhibitor. However, CPM analyses revealed differences in both size and shape of paraffin solids. The results obtained in this work reveal that in some cases the inhibitor does not modify the WAT values, but the morphology of the precipitated particles. In these cases, it is necessary to combine DSC and CPM analyses to obtain reliable results.
Abstract
The blocking problems in equipment and flowlines caused by precipitation of wax solids is a well-known problem and large research efforts have been focused on developing procedures [...]
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Enhanced biogas production from coffee pulp through deligninocellulosic photocatalytic pretreatment
G. Corro, U. Pal, S. Cebada

Energy Science & Engineering (2017).

Abstract
Production of biogas utilizing agricultural wastes is one of the most demanding technologies for generating energy in sustainable manner considering environmental concerns. However, though the agricultural wastes are available in abundance, the technologies used for the production of biogas such as biological and thermochemical processes are not very efficient. In the present article, we describe a process for the production of biogas from coffee pulp utilizing Cu/TiO2 as an efficient photocatalyst in its solar photocatalytic pretreatment, producing biogas of high caloric value at enhanced rate. The pretreatment process enhances the coffee pulp–cattle manure codigestion, producing increased amounts of methane, propane, and other combustible components of biogas. The photocatalytic pretreatment was performed using 10%Cu/TiO2 as photocatalyst, bubbling air as oxidizing agent, and solar radiation as light source. The process enhances the degradation rate of lignocellulosic components of coffee pulp, consequently increasing the biogas production through anaerobic codigestion. The mechanism of photocatalytic degradation of lignocelluloses has been discussed. The results presented in this work indicate the photocatalytic pretreatment is a useful process to increase biogas generation from lignocelluloses-rich natural wastes.
Abstract
Production of biogas utilizing agricultural wastes is one of the most demanding technologies for generating energy in sustainable manner considering environmental concerns. [...]
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Photovoltaics: between a bright outlook and uncertainty
P. Berberi, S. Thodhorjani, P. Hoxha, V. Muda

Energy Science & Engineering (2017).

Abstract
There is “breakneck” growth in the global photovoltaics market, with the global market of photovoltaic cells growing by about 47% in 2009, 72% in 2010, and 74% in 2011. Global installed capacity in 2011 was three times more than 2009. Italy and Germany are leading with a 57% share of the global market. Costs are dropping rapidly and photovoltaic (PV) power generation is an attractive option for investors. Increasing support of European Union (EU) for renewable energy in general and PV aims to diversify sources of energy and reduce reliance on fossil fuels, on nuclear and on imported energy. Energy security is an important dimension for the EU. Almost all experts agree that there is no single technology that will provide a sustainable global supply of cleaner energy. However, the scale, the cost of the change needed and supporting policy and legislation are often subject to debate. High costs could be counterbalanced by economic yields from new businesses, the creation of new jobs, and economic growth from clean energy investments. The current situation in which Germany and Italy account for almost 2/3 of global PV market growth and, also, the strong reliance on supporting policies is unstable. If PV power generation is to continue growing, the balance of development will have to shift to new markets – both inside and outside of Europe. Fixed price policy is a game to be played with caution. This article highlights examples of Spain, Italy, and Germany that illustrate that without robust policy the system can be easily misbalanced. When – or even if – photovoltaic power does become cheap enough to compete without subsidies against more established energy sources, depends upon a number of uncertainties, including the continuing political will to provide financial support, and how readily developing nations such as China and India embrace renewable energies.
Abstract
There is “breakneck” growth in the global photovoltaics market, with the global market of photovoltaic cells growing by about 47% in 2009, 72% in 2010, and 74% in 2011. [...]
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Fuel-mix and energy utilization analysis of Port Harcourt Refining Company, Nigeria
I. Badmus, R. Fagbenle, O. Oyewola

Energy Science & Engineering (2017).

Abstract
This study analyses the fuel-mix and energy utilization patterns in Port Harcourt Refining Company from 2000 to 2011. The average fuel mix over the study period is 43% refinery fuel gas, 0% liquefied petroleum gas (LPG), 44% low pour fuel oil (LPFO), 8% Coke, and 5% automotive gas oil (AGO). The present ratio of high-carbon fuel consumption to low-carbon fuel consumption adversely influences the specific fuel consumption by increasing it. Our proposal is that the present AGO and LPFO consumption levels are totally replaced with equivalent amounts of natural gas. This would yield the following fuel mix: 46% refinery fuel gas, 46% natural gas, and 8% coke. This, in effect, would result in a proportion of 92% low-carbon fuels and 8% coke. It would also lead to a specific fuel consumption that is averagely unaffected by high-carbon/low-carbon fuel consumption ratios. Natural gas utilization has its main advantage in its flare/waste and consequent environmental degradation reduction. Finally, the proposed fuel mix would generally lead to a reduction in specific fuel consumption, thus saving energy and reducing costs.
Abstract
This study analyses the fuel-mix and energy utilization patterns in Port Harcourt Refining Company from 2000 to 2011. The average fuel mix over the study period is 43% refinery [...]
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Advances on waste valorization: new horizons for a more sustainable society
R. Arancon, C. Lin, K. Chan, T. Kwan, R. Luque

Energy Science & Engineering (2017).

Abstract
Increasingly tighter regulations regarding organic waste, and the demand for renewable chemicals and fuels, are pushing the manufacturing industry toward higher sustainability to improve cost-effectiveness and meet customers’ demand. Food waste valorization is one of the current research areas that has attracted a great deal of attention over the past few years as a potential alternative to the disposal of a wide range of residues in landfill sites. In particular, the development of environmentally sound and innovative strategies to process such waste is an area of increasing importance in our current society. Landfill, incineration and composting are common, mature technologies for waste disposal. However, they are not satisfactory to treating organic waste due to the generation of toxic methane gas and bad odor, high energy consumption and slow reaction kinetics. In fact, research efforts have also been oriented on novel technologies to decompose organic waste. However, no valuable product is generated from the decomposition process. Instead of disposing and decomposing food waste, recent research has focused on its utilization as energy source (e.g., for bioethanol and biodiesel production). Organic waste is also useful to generate useful organic chemicals via biorefinery or white biotechnology (e.g., succinic acid and/or bio-plastics). This article is aimed to summarize recent development of waste valorization strategies for the sustainable production of chemicals, materials, and fuels through the development of green production strategies. It will also provide key insights into recent legislation on management of waste worldwide as well as two relevant case studies (the transformation of corncob residues into functionalized biomass-derived carbonaceous solid acids and their utilization in the production of biodiesel-like biofuels from waste oils in Philippines, as well as the development of a bakery waste based biorefinery for succinic acid and bioplastic production in Hong Kong) to illustrate the enormous potential of biowaste valorization for a more sustainable society. Future research directions and possible sustainable approaches will also be discussed with their respective proofs of concept.
Abstract
Increasingly tighter regulations regarding organic waste, and the demand for renewable chemicals and fuels, are pushing the manufacturing industry toward higher sustainability [...]
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Use of nonimmobilized enzymes and mediators achieved high power densities in closed biobatteries
Z. Zhu, Y. Zhang

Energy Science & Engineering (2017).

Abstract
The immobilization of redox enzymes on the surface of electrodes is a typical practice for enzymatic fuel cells (EFCs) but enzyme immobilization usually results in low retaining enzymatic activities and low power densities. Here, we investigated an alternative solution – the use of nonimmobilized thermostable enzymes (e.g., NAD-based glucose 6-phosphate dehydrogenase and flavin-containing diaphorase) and a nonimmobilized mediator (i.e., benzyl viologen or 9, 10-anthraquinone-2, 7-disulphonic acid, AQDS) for achieving high power densities from glucose 6-phosphate in closed EFCs (called biobatteries). At the same enzyme loading, power densities of biobatteries increased in an order from the case of immobilized enzymes and immobilized vitamin K3 to the case of nonimmobilized enzymes and immobilized vitamin K3 to the case of nonimmobilized enzymes and nonimmobilized AQDS. The maximum power density of the biobattery based on nonimmobilized enzymes and AQDS was 1.1 mW cm−2 of anode at room temperature, 34-times of the biobattery based on immobilized enzymes and immobilized vitamin K3. When enzyme loading was increased by another 10-fold, the highest power density of biobattery was increased to 2.4 mW cm−2 at 37°C. The biobattery based on nonimmobilized enzymes and AQDS retained 60% of its initial current density after running for 2 h. When repeatedly being used for 6 rounds, the biobattery had 35% of its initial current density after 12 days. Our results suggest that closed biobatteries equipped with nonimmobilized thermostable enzymes and mediators feature simple system configuration and have high power densities.
Abstract
The immobilization of redox enzymes on the surface of electrodes is a typical practice for enzymatic fuel cells (EFCs) but enzyme immobilization usually results in low retaining [...]
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Study of a new hydraulic pumping unit based on the offshore platform
Y. Yu, Z. Chang, Y. Qi, X. Xue, J. Zhao

Energy Science & Engineering (2017).

Abstract
This article introduces a new technology about a rod pumping in the offshore platform according to the demand of offshore heavy oil thermal recovery and the production of stripper well, analyzes the research status of hydraulic pumping unit at home and abroad, and designs a new kind of miniature hydraulic pumping unit with long-stroke, low pumping speed and compact structure to resolve the problem of space limitation. The article also describes the whole structure and the working principle of this pumping unit, determines the choice of stroke and rate of the pumping unit, and establishes mathematical models based on the polished rod loads. A new composite hydraulic cylinder with a special structure was designed by combining the hydraulic cylinder with the energy accumulator. This composite hydraulic cylinder is applied on land, and the model prototype runs smoothly, which indicates that the whole structure design of the pumping unit is reasonable and the control strategy is correct.
Abstract
This article introduces a new technology about a rod pumping in the offshore platform according to the demand of offshore heavy oil thermal recovery and the production of [...]
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Marginal abatement cost curve for wind power in China: a provincial-level analysis
W. Xiong, Y. Yang, Y. Wang, X. Zhang

Energy Science & Engineering (2017).

Abstract
Wind power has seen a remarkable growth in China since the Renewable Energy Law came into force in the beginning of 2006. However, the contribution and the economic cost of wind power development to reduce carbon emission at the provincial level are still unclear. This research combined geographic information system analysis and levelized production cost calculation to provide provincial-level supply curve of carbon dioxide (CO2) mitigation by wind power in China. The results showed that wind power could be a very competitive mitigation option in China, with a potential to contribute 500 million tons of CO2 emission mitigation at an average abatement cost of 75 RMB/t of CO2 mitigation. The emission abatement cost and the potential to reduce carbon emission in different provinces may be used for national planning as well as for the allocation of investments.
Abstract
Wind power has seen a remarkable growth in China since the Renewable Energy Law came into force in the beginning of 2006. However, the contribution and the economic cost of [...]
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Design of photovoltaics for modules with 50% efficiency
E. Warmann, C. Flowers, J. Lloyd, C. Eisler, M. Escarra, H. Atwater

Energy Science & Engineering (2017).

Abstract
We describe a spectrum splitting solar module design approach using ensembles of 2–20 subcells with bandgaps optimized for the AM1.5D spectrum. Device physics calculations and experimental data determine radiative efficiency parameters for III-V compound semiconductor subcells and enable modification of conventional detailed balance calculations to predict module efficiency while retaining computational speed for a wide search of the design space. Accounting for nonideal absorption and recombination rates due to realistic material imperfections allows us to identify the minimum subcell quantity, quality, electrical connection configuration, and concentration required for 50% module efficiency with realistic optical losses and modeled contact resistance losses. We predict a module efficiency of 50% or greater will be possible with 7–10 electrically independent subcells in a spectral splitting optic at 300–500 suns concentration, assuming a 90% optical efficiency and 98% electrical efficiency, provided the subcells can achieve an average external radiative efficiency of 3–5% and a short circuit current that is at least 90% of the ideal. In examining spectrum splitting solar cells with both series-connected and electrically independent subcells, we identify a new design trade-off independent of the challenges of fabricating optimal bandgap combinations. Series-connected ensembles, having a single set of electrical contacts, are less sensitive to lumped series resistance losses than ensembles where each subcells are contacted independently. By contrast, ensembles with electrically independent subcells can achieve lower radiative losses when the subcells are designed for good optical confinement. Distributing electrically independent subcells in a concentrating receiver module allows flexibility in subcell selection and fabrication, and can achieve ultra-high efficiency with conventional III-V cell technology.
Abstract
We describe a spectrum splitting solar module design approach using ensembles of 2–20 subcells with bandgaps optimized for the AM1.5D spectrum. Device physics calculations [...]
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Energy production advantage of independent subcell connection for multijunction photovoltaics
E. Warmann, H. Atwater

Energy Science & Engineering (2017).

Abstract
Increasing the number of subcells in a multijunction or “spectrum splitting” photovoltaic improves efficiency under the standard AM1.5D design spectrum, but it can lower efficiency under spectra that differ from the standard if the subcells are connected electrically in series. Using atmospheric data and the SMARTS multiple scattering and absorption model, we simulated sunny day spectra over 1 year for five locations in the United States and determined the annual energy production of spectrum splitting ensembles with 2–20 subcells connected electrically in series or independently. While electrically independent subcells have a small efficiency advantage over series-connected ensembles under the AM1.5D design spectrum, they have a pronounced energy production advantage under realistic spectra over 1 year. Simulated energy production increased with subcell number for the electrically independent ensembles, but it peaked at 8–10 subcells for those connected in series. Electrically independent ensembles with 20 subcells produce up to 27% more energy annually than the series-connected 20-subcell ensemble. This energy production advantage persists when clouds are accounted for.
Abstract
Increasing the number of subcells in a multijunction or “spectrum splitting” photovoltaic improves efficiency under the standard AM1.5D design spectrum, but it can lower [...]
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Status and future strategies for Concentrating Solar Power in China
J. Wang, S. Yang, C. Jiang, Y. Zhang, P. Lund

Energy Science & Engineering (2017).

Abstract
China is the world leader in several areas of clean energy, but not in Concentrating Solar Power (CSP). Our analysis provides an interesting viewpoint to Chinas possible role in helping with the market breakthrough of CSP. We present a short overview of the state-of-the-art of CSP including the status in China. A blueprint for Chinas CSP development is elaborated based on Chinas 13th 5-year program, but also on Chinas previous success factors in PV and wind power. The results of this study suggest that China could play a more prominent global role in CSP, but this would require stronger efforts in several areas ranging from innovation to policies.
Abstract
China is the world leader in several areas of clean energy, but not in Concentrating Solar Power (CSP). Our analysis provides an interesting viewpoint to Chinas possible role [...]
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Tracing the energy footprints of Indonesian manufacturing industry
Y. Vivadinar, W. Purwanto, A. Saputra

Energy Science & Engineering (2017).

Abstract
The low energy efficiency is the source of the large energy consumption issue and the rapid growth of energy demand in the manufacturing industry sector in Indonesia. The driving forces behind the low energy efficiency situation in this sector are both economic and efficiency factors. The objective of this study is to generate the map of the energy flow in the manufacturing industry sector to investigate the energy utilization in the industrial process. The data sample that represents 80% of energy consumption in the manufacturing sector is used to generate this map. The generated map shows the heating system is the largest energy consumer among all energy equipment and as the primary source of the energy losses. Additionally, we found the industry groups such as sugar, cement, pulp and paper, and textile use enormous amounts of energy as their source for the heating system, meanwhile, the industries such as basic chemical, metal, and textile are the largest electricity consumers for their motor-driven machinery. The energy flow analysis together with the comparison of the Specific Energy Consumption shows the areas that should be the focus for further energy conservation measures. Recommended measures are also discussed.
Abstract
The low energy efficiency is the source of the large energy consumption issue and the rapid growth of energy demand in the manufacturing industry sector in Indonesia. The [...]
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Lock-in thermography as a tool for quality control of photovoltaic modules
A. Vetter, F. Fecher, J. Adams, R. Schaeffler, J. Theisen, C. Brabec, C. Buerhop

Energy Science & Engineering (2017).

Abstract
In this short communication, we present a method which utilizes contactless ILIT (illuminated lock-in thermography) measurement of a photovoltaic (PV) module and image postprocessing in order to calculate the peak power Pmpp of the module and to study the influence of local defects on the module performance. In total, 103 Copper-Indium-Gallium-Diselenide (CIGS) modules were investigated and the results showed a good correlation (mean error less than 6%) between the calculated IR-signal and the measured Pmpp. We performed our study on CIGS modules but the presented approach is not restricted to CIGS modules. The method provides a valuable tool for PV quality control.
Abstract
In this short communication, we present a method which utilizes contactless ILIT (illuminated lock-in thermography) measurement of a photovoltaic (PV) module and image postprocessing [...]
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Reactivity of CaO with CO2 in molten CaF2–NaF: formation and decomposition of carbonates
V. Tomkute, A. Solheim, S. Sakirzanovas, E. Olsen

Energy Science & Engineering (2017).

Abstract
The characteristics of CO2 reacting with CaO in a molten eutectic mixture of CaF2 and NaF has been investigated. Calculations of the Gibbs free energy, temperature analysis of the decomposition of the formed carbonates, and XRD analyses of quenched samples taken during CO2 absorption or desorption were employed to identify the phases present in the melt. Efficient CO2 absorption from a simulated flue gas was observed, due to a combined reaction where CaO initially reacts with CO2 and forms CaCO3. Subsequently, Na2CO3 is formed by an ion exchange reaction between CaCO3 and NaF. It was found that the CaO activity is highest in the temperature range 826–834°C. Increasing the CaO concentration from 5 to 20 wt% in the molten salt resulted in reduced CO2 reactivity efficiency, probably because of precipitation and agglomeration of the sorbent. The total carbonation conversion was independent of the CO2 concentration in the inlet gas, and the sorbent carrying capacity was in the range 0.722–0.743 g CO2/g CaO corresponding to 0.037–0.144 g CO2/g total liquid. Decarbonation was conducted by raising the temperature. 40% conversion back to CaO was recorded at 1160°C. The recorded curves for the CO2 concentration in the outlet gas exhibited a rapid desorption step followed by a slow step.
Abstract
The characteristics of CO2 reacting with CaO in a molten eutectic mixture of CaF2 and NaF has been investigated. Calculations of the Gibbs free energy, temperature analysis [...]
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Cover Image
A. Tolbert, A. Ragauskas

Energy Science & Engineering (2017).

Abstract
The cover image, by Allison Tolbert and Arthur J. Ragauskas, is based on the Review Advances in understanding the surface chemistry of lignocellulosic biomass via time-of-flight secondary ion mass spectrometry, DOI: 10.1002/ese3.144. The authors would like to acknowledge the following image contributors: Robert Davies (Renewable Bioproducts Institute, Georgia Tech) greatly assisted with the image formatting, Wellington Muchero and Jay Chen (Oak Ridge National Laboratory) and Bruce Arey (Environmental Molecular Science Laboratory) provided the Helium Ion Microscope image of Populus cell walls, and Chang Geun Yoo (Oak Ridge National Laboratory) assisted with the creative design.
Abstract
The cover image, by Allison Tolbert and Arthur J. Ragauskas, is based on the Review Advances in understanding the surface chemistry of lignocellulosic biomass via time-of-flight [...]
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Advances in understanding the surface chemistry of lignocellulosic biomass via time-of-flight secondary ion mass spectrometry
A. Tolbert, A. Ragauskas

Energy Science & Engineering (2017).

Abstract
Overcoming the natural recalcitrance of lignocellulosic biomass is necessary in order to efficiently convert biomass into biofuels or biomaterials and many times this requires some type of chemical pretreatment and/or biological treatment. While bulk chemical analysis is the traditional method of determining the impact a treatment has on biomass, the chemistry on the surface of the sample can differ from the bulk chemistry. Specifically, enzymes and microorganisms bind to the surface of the biomass and their efficiency could be greatly impacted by the chemistry of the surface. Therefore, it is important to study and understand the chemistry of the biomass at the surface. Time-of-flight secondary ion mass spectrometry (ToF-SIMS) is a powerful tool that can spectrally and spatially analyze the surface chemistry of a sample. This review discusses the advances in understanding lignocellulosic biomass surface chemistry using the ToF-SIMS by addressing the instrument parameters, biomass sample preparation, and characteristic lignocellulosic ion fragmentation peaks along with their typical location in the plant cell wall. The use of the ToF-SIMS in detecting chemical changes due to chemical pretreatments, microbial treatments, and physical or genetic modifications is discussed along with possible future applications of the instrument in lignocellulosic biomass studies.
Abstract
Overcoming the natural recalcitrance of lignocellulosic biomass is necessary in order to efficiently convert biomass into biofuels or biomaterials and many times this requires [...]
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In situ synchrotron-based X-ray powder diffraction and micro-Raman study of biomass and residue model compounds at hydrothermal conditions
M. Thomas, I. Butler, J. Kozinski

Energy Science & Engineering (2017).

Abstract
The applications of synchrotron X-ray powder diffraction (XRPD) and laser micro-Raman techniques in an examination of the dissolution, transformation, and gasification of pure cellulose and models for biomass residue under hydrothermal conditions in a diamond-anvil cell are reported. The results contribute to the measurement of in situ time-resolved profiles of biomass reactions, catalyst stability, and residue formation that occur in aqueous fluids at near- and supercritical conditions.
Abstract
The applications of synchrotron X-ray powder diffraction (XRPD) and laser micro-Raman techniques in an examination of the dissolution, transformation, and gasification of [...]
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Fuzzy ARTMAP and GARCH-based hybrid model aided with wavelet transform for short-term electricity load forecasting
S. Takiyar, K. Upadhyay, V. Singh

Energy Science & Engineering (2017).

Abstract
With the evolution of the electricity market into a restructured smart version, load forecasting has emerged as an eminent research domain. Many forecasting models have been proposed by researchers for electricity price and load forecasting. This state of art introduces a load time series modeled with a hybrid technique culminating from the logical amalgamation of GARCH, a conventional hard computing method, Fuzzy ARTMAP, an artificial intelligence-based soft computing technique, and wavelet transform, for treating the load time series. The study investigates into the ability of the proposed hybrid model in tackling the electricity load time series forecasting problems. The work under this study also includes comparisons drawn among models which use either one or two of the mentioned techniques and the model proposed. Results certify the efficacy and effectiveness of the model over others.
Abstract
With the evolution of the electricity market into a restructured smart version, load forecasting has emerged as an eminent research domain. Many forecasting models have been [...]
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Three-dimensional energetic and exergetic analysis of the injection orientation of DI diesel engine under different engine speeds
H. Taghavifar, S. Khalilarya, S. Jafarmadar

Energy Science & Engineering (2017).

Abstract
Three-dimensional (3-D) computational code was implemented to solve conservation equations based on finite volume method as to simulate 1.8 L Ford diesel engine. Velocity and pressure of each computational cell is achieved by SIMPLE (semi-implicit method for pressure-linked equations) algorithm. For the exergetic aspect, the initial condition is set at 0.1 MPa and 300 K. The engine modeling is performed with 130 °, 140 °, and 150 ° with respect to x-axis under 1500 and 2500 rpm engine speeds. The results, however, indicate better air/fuel mixture (near stoichiometric equivalence ratio) for 130 ° of injection angle, albeit smaller spray droplets (lower sauter mean diameter) were introduced with 140 °. It is seen that higher soot and NOx mass fraction is attributed to 1500 rpm engine speed. The highest NOx and soot are exhausted at 130 ° and 150 ° of injection, respectively. Second law efficiency was calculated for different spray angle and engine speed schemes such that 36.62%, 30.2%, and 32.07% are associated with 130 °, 140 °, and 150 ° of injection angle under 1500 rpm, respectively. In terms of engine performance, that is, indicated mean effective pressure, indicated specific fuel consumption, and temperature, the best performance metrics are of 130 ° equal to 15.4 bar, 0.3856 kg/kW-h, and 2074.97 K under 1500 rpm, respectively. Instant irreversibility rate is the highest amount with peak value of 17.48 J/deg for 130 deg-1500 rpm, while 140 ° shows higher mean irreversibility rate over crank angle (CA) period.
Abstract
Three-dimensional (3-D) computational code was implemented to solve conservation equations based on finite volume method as to simulate 1.8 L Ford diesel engine. Velocity [...]
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Shale gas in North America and Europe
M. Stephenson

Energy Science & Engineering (2017).

Abstract
According to the U.S. Energy Information Administration, shale gas will provide half of the United States’ domestic gas by 2035. The United States has already moved from being one of the worlds largest importers of gas to being self-sufficient in less than a decade, bringing hundreds of thousands of jobs and attracting back companies that long ago left America in search of cheap manufacturing costs. But the increase in shale gas extraction has also had an environmental cost. There is clear scientific evidence of leaking shale gas wells and induced earthquakes, and in some areas a population increasingly turning against the industry. The technology of horizontal drilling and hydraulic fracturing that was developed in the United States is now being tried outside the United States, including in Europe, Argentina, and China. There are clear reasons why shale gas might be attractive to Europe. It may offer security of energy supply to some countries particularly dependent on Russian gas, it could stimulate growth and jobs, and it could supply a cleaner fuel than coal in power stations. However, prospective shale often underlies areas of high population density in Europe, and moreover, populations that are unfamiliar with onshore gas operations. The main challenge in Europe therefore is not mainly technological but for the industry to achieve a “social license” and for Government and regulations to be manifestly protecting the public and property.
Abstract
According to the U.S. Energy Information Administration, shale gas will provide half of the United States’ domestic gas by 2035. The United States has already moved from [...]
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A study of the annual performance of bifacial photovoltaic modules in the case of vertical facade integration
B. Soria, E. Gerritsen, P. Lefillastre, J. Broquin

Energy Science & Engineering (2017).

Abstract
Despite the apparent benefits of bifacial modules, their application still suffers from a lack of visibility on the performance gain that they can actually provide. In this work, we consider the specific application of vertically oriented bifacial modules, notably for facade integration. We have developed a methodology to evaluate the annual electrical performance of bifacial modules based on three tools. First, a double illumination characterization setup is used in a solar simulator for comparing module architectures. Then, a reduced scale outdoor test bench allows us to evaluate bifacial module performance in a variety of configurations. Finally, a ray-tracing model validated with short-term outdoor data leads to the determination of the annual performance gain. This methodology allowed us to find optimal performance according to the most important parameters of application and module. Specifically, a module architecture using half-cut cells, a parallel cell interconnection, and textured glasses have been analyzed with respect to their influence on the resistive losses which increase in dual side illumination as well as to their influence on the effect of non- uniform and diffuse irradiance on the backside of the module. This work enabled us to give directions for innovative full-size module architectures.
Abstract
Despite the apparent benefits of bifacial modules, their application still suffers from a lack of visibility on the performance gain that they can actually provide. In this [...]
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Outdoor characterization and comparison of string and MLPE under clear and partially shaded conditions
K. Sinapis, G. Litjens, M. Donker, W. Folkerts, W. Sark

Energy Science & Engineering (2017).

Abstract
Building integrated and building attached photovoltaic (BIPV, BAPV) systems may suffer from lower performance than predicted as a result of unwanted partial shading. New system architectures have been proposed to optimize performance. The common approach of these new architectures is to track the maximum power point of every solar module individually. This paper demonstrates the effect of shading on energy yield by evaluating power level management on the module level compared to string level. Three independent PV systems were installed and extensively monitored in Eindhoven, a reference string inverter system, a power optimizer system and a micro inverter system. The DC and AC performance ratio (PR) of the systems have been analyzed for different weather types based on the clearness index. A pole shading covering 1–2% of the total system surface has been used to evaluate system performance under a specific type of partial shading. Module Level Power Electronics (MLPE) is capable of increasing the PR up to 35% under certain partial shading conditions. However, the string inverter system outperformed MLPE under unshaded operation conditions.
Abstract
Building integrated and building attached photovoltaic (BIPV, BAPV) systems may suffer from lower performance than predicted as a result of unwanted partial shading. New system [...]
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Ultrasound-assisted transesterification of refined and crude palm oils using heterogeneous palm oil mill fly ash supported calcium oxide catalyst
W. Ho, H. Ng, S. Gan, W. Chan

Energy Science & Engineering (2017).

Abstract
Ultrasound-assisted transesterification of refined palm oil (RPO) and crude palm oil (CPO) to produce biodiesel using a palm oil mill fly ash supported calcium oxide (CaO) catalyst is studied in this work. The reaction time is significantly reduced from a maximum of 360 min under conventional mixing to just 30 min with the use of ultrasound. Under ultrasonic cavitation, the required catalyst loading and methanol to oil molar ratio to produce comparable yields and fatty acid methyl esters (FAME) conversions as conventional mixing are lower. For RPO, the ultrasound-assisted transesterification conditions of 60% ultrasonic amplitude, 30 min reaction time, 4 wt.% catalyst loading, and 9:1 methanol to oil molar ratio result in maximum biodiesel yield and FAME conversion of 85.23% and 97.02%, respectively. As for CPO, maximum biodiesel yield of 73.23% and FAME conversion of 97.04% are obtained under the same conditions with the exception of a methanol to oil molar ratio of 12:1. Key physicochemical properties of the produced biodiesels are found to be within the limits set by EN 14214 and ASTM D 6751. Catalyst reusability tests indicate that the catalyst can be used up to three consecutive cycles after regeneration using methanol washing followed by recalcination at 850°C for 2 h.
Abstract
Ultrasound-assisted transesterification of refined palm oil (RPO) and crude palm oil (CPO) to produce biodiesel using a palm oil mill fly ash supported calcium oxide (CaO) [...]
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High moisture corn stover pelleting in a flat die pellet mill fitted with a 6 mm die: physical properties and specific energy consumption
J. Tumuluru

Energy Science & Engineering (2017).

Abstract
The quality and specific energy consumption (SEC) of the biomass pellets produced depend upon pelleting process conditions. The present study includes understanding the effect of feedstock moisture in the range of 28–38% (wet basis [w.b.]) and preheating in the range of 30–110°C at two die speeds of 40 and 60 Hz on the physical properties and SEC. A flat die pellet mill fitted with a 6 mm die was used in the present study. The physical properties of pellets such as moisture content, unit, bulk and tapped density, durability, and expansion ratio and SEC of the pelleting process are measured. The results indicate that the pellets produced have durability values in the range of 87–98%, and unit bulk and tapped density in the range of 670–1100, 375–575, and 420–620 kg/m3. Increasing the feedstock moisture content from 33% to 38% (w.b) decreased the unit, bulk and tapped density by about 30–40%. Increasing feedstock moisture content increased the expansion ratio and decreased the density values. A higher feedstock moisture content of 38% (w.b.) and higher preheating temperature of 110°C resulted in lower density and a higher expansion ratio, which can be attributed to flash off of moisture as the material extrudes out of the die. The SEC was in the range of 75–275 kWh/ton. Higher feedstock moisture content of 38% (w.b.) and a lower die speed of 40 Hz increased the SEC, whereas lower to medium preheating temperature (30–70°C), medium feedstock moisture content of 33% (w.b.), and a higher die speed of 60 Hz minimized the SEC to
Abstract
The quality and specific energy consumption (SEC) of the biomass pellets produced depend upon pelleting process conditions. The present study includes understanding the effect [...]
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Amorphous single-junction cells for vertical BIPV application with high bifaciality
N. Reininghaus, C. Feser, B. Hanke, M. Vehse, C. Agert

Energy Science & Engineering (2017).

Abstract
Solar cells used in building integration of photovoltaic cells (BIPV) are commonly made from crystalline wafer cells. This contribution investigates the challenges and benefits of using bifacial solar cells in vertical installations. We show that those cells get up to 13% more irradiance compared to optimum tilted south facing monofacial modules in Germany. The role of the n-layer in thin amorphous bifacial single-junction cells intended to be used as bifacial cells in BIPV applications is investigated. In contrast to the superstrate cell design, a transparent n-layer and back contact play a key role to achieve high bifaciality. We therefore increased the transparency of the n-layer by adding CO2, increasing the PH3 flow in the deposition gas and tested different thicknesses. With those measures, we reached a bifaciality of 98% for short-circuit current density and 99% for open-circuit voltage.
Abstract
Solar cells used in building integration of photovoltaic cells (BIPV) are commonly made from crystalline wafer cells. This contribution investigates the challenges and benefits [...]
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Degradation of silicon wafers at high temperatures for epitaxial deposition
T. Rachow, S. Reber, S. Janz, M. Knapp, N. Milenkovic

Energy Science & Engineering (2017).

Abstract
The material quality degradation of silicon wafers by metal impurities, various crystal defects as well as light and thermally induced mechanisms is very important for the solar cell performance and has been investigated by various groups. In this paper, the material degradation during epitaxial deposition at high temperatures above 1100°C will be discussed. Annealing experiments in hydrogen atmosphere are done with the laboratory rapid thermal chemical vapor deposition reactor to mimic the thermal process conditions for epitaxial growth of silicon from the gas phase. A general investigation of crystallographic and electronic properties of n- and p-type silicon wafers has been done between 950°C and 1150°C. A detailed sensitivity analysis of process parameters like cooling ramp, peak temperature, duration, and ambient gasses has been conducted. The degradation mechanism by metal impurities has been investigated by using silicon wafers with different diffusion barriers. Besides effective minority carrier lifetime, measurements by quasi steady state photo conductance, etch pit density, Raman spectroscopy, X-ray diffraction, and Fourier transform infrared spectroscopy measurements have been done. The presented results have been used to improve the deposition process of epitaxial thin-film solar cells, the production of silicon foils with a thickness
Abstract
The material quality degradation of silicon wafers by metal impurities, various crystal defects as well as light and thermally induced mechanisms is very important for the [...]
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Next generation biorefineries will solve the food, biofuels, and environmental trilemma in the energy–food–water nexus
Y. Zhang

Energy Science & Engineering (2017).

Abstract
The future roles of biomass and carbohydrate for meeting needs of food/feed, renewable materials, and transportation fuels (biofuels) remain controversial due to numerous issues, such as increasing food and feed needs, constraints of natural resources (land, water, phosphate, biomass, etc.), and limitations of natural photosynthesis, as well as competing energy conversion pathways and technologies. The goal of this opinion article is to clarify the future roles of biomass and biorefineries using quantitative data other than adjective words. In most scenarios, human beings could have enough biomass resource from plant photosynthesis for meeting the three goals at the same time: feeding 9 billion people, providing renewable materials, and producing transportation biofuels that could replace nearly all fossil fuel-based liquid fuels used in the land transportation in 2050. Land transport means will pass through transitions from internal combustion engines plus liquid fuels, to hybrid systems, to hydrogen fuel cell vehicles (FCVs), while battery electric vehicles (BEVs) could play a minor role. Next generation biorefineries based on artificial photosynthesis featuring ultra-high energy efficiency and low-water consumption could produce a large amount of carbohydrate and/or other biocommodities from hydrogen/electricity and CO2. In conclusion, it is time to develop next generation biorefineries, which will efficiently utilize nonfood biomass for the coproduction of multiple products from biofuels, biochemicals, to food/feed, and even store electricity/hydrogen by fixing CO2 to carbon-containing chemicals and biofuels. Next generation biorefineries will address the food, biofuels, and environment trilemma at the same time.
Abstract
The future roles of biomass and carbohydrate for meeting needs of food/feed, renewable materials, and transportation fuels (biofuels) remain controversial due to numerous [...]
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Low-grade heat recycling for system synergies between waste heat and food production, a case study at the European Spallation Source
T. Parker, A. Kiessling

Energy Science & Engineering (2017).

Abstract
At present food production depends almost exclusively on direct use of stored energy sources, may perhaps they be nuclear-, petroleum-, or biobased. Arable land, artificial fertilizers, and fresh water resources are the base for our present food systems, but are limited. At the same time, energy resources in the form of waste heat are available in ample quantities. The European Spallation Source (ESS) will require approximately 270 GWh of power per year to operate, power that ultimately is converted to heat. This multidisciplinary case study details an alternative food production cooling chain, using low-grade surplus heat, and involving fermentation, aquaculture, nutrient recapture, and greenhouse horticulture including both use of low-grade surplus heat and recycling of societys organic waste that is converted to animal feed and fertilizer. The study indicates that by combining the use of surplus energy with harvest of societys organic side flows, for example, food waste and aquatic-based cash crops, sustainable food systems are possible at a level of significance also for global food security. The effects of the proposed heat reuse model are discussed in a system perspective and in the context of the UNSCD indicator framework. The potential sustainability benefits of such an effort are shown to be substantial and multifaceted.
Abstract
At present food production depends almost exclusively on direct use of stored energy sources, may perhaps they be nuclear-, petroleum-, or biobased. Arable land, artificial [...]
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Thermoeconomic and thermoenvironomic modeling and analysis of selected gas turbine power plants in Nigeria
S. Oyedepo, R. Fagbenle, S. Adefila, M. Alam

Energy Science & Engineering (2017).

Abstract
This study presents comprehensive thermoeconomic and thermoenvironomic modeling and analysis of selected gas turbine power plants in Nigeria using the first and second laws of thermodynamics (exergy) concept. Exergetic analysis was conducted using operating data obtained from the power plants to determine the exergy destruction and exergy efficiency of each major component of the gas turbine in each power plant. The results of the study showed that the combustion chamber (CC) is the most exergy destructive component compared to other cycle components. The percentage of exergy destruction in CC varies between 86.05% and 94.6%. By increasing the gas turbine inlet temperature (GTIT), the exergy destruction of this component can be reduced. The total exergy improvement potential of the selected plants varies from 54.04 to 159.88 MW. The component with the highest exergy improvement potential is the CC, which has the value that varies from 30.21 to 88.86 MW. Thermoeconomic analysis showed that the cost of exergy destruction is high in the CC, and an increase in the GTIT effectively decreases this cost. The exergy costing analysis revealed that the unit cost of electricity produced in the plants ranged from cents 1.99/kWh (N3.16/kWh) to cents 5.65 /kWh (N8.98/kWh). Thermoenvironomic analysis showed that the CO2 emissions varied between 100.18 and 408.78 kg CO2/MWh, while cost rate of environmental impact varied from 40.18 $/h (6, 388.62 N/h) to 276.97 $/h (44, 038. 23 N/h). The results further showed that CO2 emissions and cost of environmental impact decrease with increasing GTIT. The sustainability index increase with increasing GTIT. Finally, this study will assist efforts to understand the thermodynamic losses in the gas turbine cycle, and to improve efficiency as well as provide future recommendations for better performance, sustainability, and lessening environmental impact of power plant.
Abstract
This study presents comprehensive thermoeconomic and thermoenvironomic modeling and analysis of selected gas turbine power plants in Nigeria using the first and second laws [...]
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Assessment of performance indices of selected gas turbine power plants in Nigeria
S. Oyedepo, R. Fagbenle, S. Adefila

Energy Science & Engineering (2017).

Abstract
In this study, performance assessment of selected gas turbine power plants in Nigeria was evaluated using performance indices. The results of the study showed that for the period under review (2006–2010), the percentage shortfalls from the target energy in the selected power plants range from 26.33% to 86.61% as against the acceptable value of 5–10%. The capacity factor of the selected power plants varies from 16.88% to 73.67% as against the international value of 50–80%. The plant use factor varies from 45.89% to 97.03% and the utilization factor varies from 6.31% to 93.074% as against the international best practice of over 95%. From this result, it can be concluded that the generating units were underutilized. This is due to inadequate routine maintenance and equipment fault development. The analyses of reliability indicators revealed that the mean time between failures varies from 5.42 to 378.44 h, the mean time to repair varies from 18.3 to 153.88 h and the plant availability varies from 12.86% to 91.31% as against the Institute of Electrical and Electronics Engineers recommended standard of 99.9%. Evaluation of operating figures of the selected power plants revealed that starting reliability (SR) and operating reliability vary from 71.95% to 93.9% and 5.33% to 55%, respectively. The SR of the selected power plants is low in value compared with standard value of 99.9%. The statistical analysis carried out on plant availability revealed that at 95% confidence level, there is a significant difference in availability of the selected power plants. This indicates differences in their systems installation, operation and maintenance. The performance indicator developed to evaluate the performance indices for the selected stations can also be applicable to other power stations in Nigeria and elsewhere. Measures to improve the performance indices of the plants have been suggested in this paper.
Abstract
In this study, performance assessment of selected gas turbine power plants in Nigeria was evaluated using performance indices. The results of the study showed that for the [...]
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Techno-economic analysis of hybrid PV–diesel–battery and PV–wind–diesel–battery power systems for mobile BTS: the way forward for rural development
L. Olatomiwa, S. Mekhilef, A. Huda, K. Sanusi

Energy Science & Engineering (2017).

Abstract
In recent times, hybrid renewable energy systems are increasingly being utilized to provide electricity in remote areas especially where the grid extension is considered too expensive. This study presents the results of techno-economic analysis of hybrid system comprising of solar and wind energy for powering a specific remote mobile base transceiver station (BTS) in Nigeria. All the necessary modeling, simulation, and techno-economic evaluation are carried out using the assessment software package HOMER (Hybrid Optimization Model for Electric Renewable). Two best optimal system configurations namely PV–diesel–battery and PV–wind–diesel–battery systems are compared with the conventional stand-alone diesel generator (DG) system. Findings indicated that PV array (10 kW) – DG (5.5 kW) – battery (64 units Trojan L16P) is the most economically viable option with the total net present cost of $69, 811 and per unit cost of electricity of $0.409. The sensitivity analysis is also carried out to find the effects of probable variation in solar radiation, wind speed, and diesel price in the optimal system configurations. Finally, the environmental benefit of hybrid systems over the conventional stand-alone diesel system is described. The obtained results show that the hybrid PV–diesel–battery system provides a reduction in CO2 emissions of about 16.4 tons per year as compared to the stand-alone DG system.
Abstract
In recent times, hybrid renewable energy systems are increasingly being utilized to provide electricity in remote areas especially where the grid extension is considered too [...]
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Irradiance adjustment system developed for various types of solar cells and illumination conditions
Y. Nishikawa, K. Imai, K. Miyao, S. Uchida, D. Aoki, H. Saito, S. Magaino, K. Takagi

Energy Science & Engineering (2017).

Abstract
A new irradiance adjustment system for the light source named “Programmable Reference cell system for Irradiance adjustment by Spectral Measurement (PRISM)” has been developed for photovoltaics evaluation. It can be applied for various kinds of solar cells and illumination conditions without the preparation of conventional reference cells. This system consists of a device for absolute spectral responsivity measurements, that is, the spectral responsivity unit, and a device for irradiance adjustment of the light source, that is, the spectral reference cell. First, the short circuit current of the target solar cell (Iref) is calculated by convolution of the absolute spectral responsivity with the spectral irradiance under STC (AM1.5 G, 1 kW/m2, 25°C) as defined in IEC 60904-3. The spectral irradiance of the light source is then adjusted for I–V measurements so that the short-circuit current of the spectral reference cell (Ical), calculated by convolution of the absolute spectral responsivity with the spectral irradiance of the light source, agrees with Iref. The difference between Iref and the short circuit current, as determined at an internationally recognized test center under STC, was within ±2% for crystalline silicon solar cells and ±3% for organic solar cells. The difference between Ical and the short-circuit current measured under a solar simulator or LED in which the irradiance was adjusted by this system was within ±4% when the irradiance was higher than 4 W/m2.
Abstract
A new irradiance adjustment system for the light source named “Programmable Reference cell system for Irradiance adjustment by Spectral Measurement (PRISM)” has been developed [...]
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