International Journal of Photoenergy The latest articles from Hindawi Publishing Corporation © 2015 , Hindawi Publishing Corporation . All rights reserved. Quantum Sized Zinc Oxide Immobilized on Bentonite Clay and Degradation of C.I. Acid Red 35 in Aqueous under Ultraviolet Light Thu, 08 Oct 2015 07:05:43 +0000 Nano-ZnO supported on bentonite was prepared to form composite photocatalyst by sol-gel method. The photocatalyst was analyzed by X-ray diffraction (XRD), scanning electron microscopy (SEM), and transmission electron microscope (TEM). C.I. Acid Red 35 was used as simulating contaminant to be treated by ultraviolet light synergistic with nano-ZnO/bentonite. The results show that 5.7 nm ZnO particle was acquired and uniformly dispersed on the surface of the bentonite at calcination temperature of 200°C. The removal of C.I. Acid Red 35 could reach 84.9% after 200 min under optimum ZnO/bentonite dosage of 0.6 g L−1. The 60% ZnO content in ZnO/bentonite composite exhibited a great photocatalytic activity to treat C.I. Acid Red 35. The photocatalytic process followed pseudo-first-order kinetics and the best apparent rate constant was 0.00927 min−1 with correlation coefficient (R2) of above 0.98. Hang Xu, Dandan Zhang, Airong Xu, Fengmin Wu, and Renqiang Cao Copyright © 2015 Hang Xu et al. All rights reserved. New Architecture towards Ultrathin CdTe Solar Cells for High Conversion Efficiency Mon, 05 Oct 2015 10:46:24 +0000 Solar Cell Capacitance Simulator in 1 Dimension (SCAPS-1D) is used to investigate the possibility of realizing ultrathin CdTe based solar cells with high and stable conversion efficiency. In the first step, we modified the conventional cell structure by substituting the CdS window layer with a CdS:O film having a wide band gap ranging from 2.42 to 3.17 eV. Thereafter, we simulated the quantum efficiency, as well as the parameters of J-V characteristics, and showed how the thickness of CdS:O layer influences output parameters of Glass/SnO2/ZTO/CdS:O/CdT/CdTe/Ni reference cell. High conversion efficiency of 17.30% has been found using CdT () and CdTe layers of thickness 15 nm and 4 μm, respectively. Secondly, we introduced a BSR layer between the absorber layer and back metal contact, which led to Glass/SnO2/ZTO/CdS:O/CdT/CdTe/BSR/Ni configuration. We found that a few nanometers (about 5 nm) of CdT layer is sufficient to obtain high conversion efficiency. For BSR layer, different materials with large band gap, such as ZnTe, Cu2Te, and p+-CdTe, have been used in order to reduce minority carrier recombination at the back contact. When ZnTe is used, high conversion efficiency of 21.65% and better stability are obtained, compared to other BSR. A. Teyou Ngoupo, S. Ouédraogo, F. Zougmoré, and J. M. B. Ndjaka Copyright © 2015 A. Teyou Ngoupo et al. All rights reserved. Investigation of Poly(3,4-ethylenedioxythiophene):Poly(styrenesulfonate) Hole Transport Layer for Solution-Processed Polymer Solar Cells Mon, 05 Oct 2015 08:13:20 +0000 The inverted polymer solar cell was prepared by self-made spray-coating system, and the poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate) (PEDOT:PSS) hole transport layer was studied. 220 nm poly-(3-hexylthiophene):[6,6]-phenylC61butyric-acid methyl-ester (P3HT:PCBM) and 40 nm PEDOT:PSS were deposited on ZnO thin film subsequently by solution spray coating. Different volume of isopropyl alcohol was introduced into PEDOT:PSS to decrease the contact angle and obtain the optimum Marangoni flow. The surface morphology and roughness of PEDOT:PSS films were characterized by atomic force microscopy with varied deposition temperature from 70°C to 160°C. The improvement of power conversion efficiency (PCE) was attributed to the enhancement of vertical phase separation in PEDOT:PSS film, which improved the charge transfer in the bulk cell. The highest PCE of spray-coated PSCs reached 2.80% after postannealing for 10 min. Chengxi Zhang, Jiang Cheng, Xiaoqing Liao, Xiaojuan Lian, Jin Zhang, Xin Yang, and Lu Li Copyright © 2015 Chengxi Zhang et al. All rights reserved. Blue to Yellow Photoluminescence Emission and Photocatalytic Activity of Nitrogen Doping in TiO2 Powders Mon, 05 Oct 2015 06:56:04 +0000 The defects caused by doping are important for understanding the increased photocatalytic activities of TiO2:N in organic reactions and in the evaluation of OH radical production after doping. TiO2:N was therefore synthesized using a modified polymeric method and N doping was performed by calcination with urea. The resulting powders were characterized using field emission scanning electron microscopy, X-ray diffraction, diffuse reflectance spectroscopy, Raman spectroscopy, Fourier transformation infrared spectroscopy, and photoluminescence emission spectroscopy (PL). N doping did not alter the morphology of the nanoparticles, and the anatase phase predominated, with the retention of the rutile phase. The band gap values, superficial areas, and crystallite sizes of the powders decreased after doping. The PL results showed an additional energy level in the TiO2:N band gap structure as a result of TiO2 lattice defects caused by doping. At low N contents, the powders showed continuous emissions from the blue region to the yellow region and a high N content shifted the PL emissions to the red region. These results suggest that the use of these powders could increase the efficiencies of solar cells and water-splitting processes. The photocatalytic activity of the powders under UVC illumination was confirmed for different organic dye molecules. The OH radical production did not change extensively after doping, as shown by experiments with terephthalic acid, and higher photocatalytic efficiencies in Rhodamine-B degradation under UVC illumination were achieved using the doped samples. Gabriela Byzynski, Caue Ribeiro, and Elson Longo Copyright © 2015 Gabriela Byzynski et al. All rights reserved. Hydrophobic ZnO-TiO2 Nanocomposite with Photocatalytic Promoting Self-Cleaning Surface Sun, 04 Oct 2015 14:53:46 +0000 The hydrophobicity and self-cleaning are the important influence factors on the precision and environment resistance of quartz crystal microbalance (QCM) in detecting organic gas molecules. In this paper, ZnO nanorod array is prepared via the in situ method on the QCM coated with Au film via hydrothermal process. ZnO nanorod array film on QCM is modified by β-CD in hydrothermal process and then decorated by TiO2 after being impregnated in P25 suspension. The results show that as-prepared ZnO-TiO2 nanocomposite exhibits excellent hydrophobicity for water molecules and superior self-cleaning property for organic molecules under UV irradiation. Qiang Wei, Shaodan Wang, Wei Li, Xiaoxue Yuan, and Yu Bai Copyright © 2015 Qiang Wei et al. All rights reserved. Effect of 660 nm Light-Emitting Diode on the Wound Healing in Fibroblast-Like Cell Lines Sun, 04 Oct 2015 14:09:39 +0000 Light in the red to near-infrared (NIR) range (630–1000 nm), which is generated using low energy laser or light-emitting diode (LED) arrays, was reported to have a range of beneficial biological effects in many injury models. NIR via a LED is a well-accepted therapeutic tool for the treatment of infected, ischemic, and hypoxic wounds as well as other soft tissue injuries in humans and animals. This study examined the effects of exposure to 660 nm red LED light at intensities of 2.5, 5.5, and 8.5 mW/cm2 for 5, 10, and 20 min on wound healing and proliferation in fibroblast-like cells, such as L929 mouse fibroblasts and human gingival fibroblasts (HGF-1). A photo illumination-cell culture system was designed to evaluate the cell proliferation and wound healing of fibroblast-like cells exposed to 600 nm LED light. The cell proliferation was evaluated by MTT assay, and a scratched wound assay was performed to assess the rate of migrating cells and the healing effect. Exposure to the 660 nm red LED resulted in an increase in cell proliferation and migration compared to the control, indicating its potential use as a phototherapeutic agent. Myung-Sun Kim, Yong-Ick Cho, Min-Suk Kook, Sang-Chul Jung, Young-Hyun Hwang, and Byung-Hoon Kim Copyright © 2015 Myung-Sun Kim et al. All rights reserved. Application of a Noncarboxylated Dye Compound in a Dye-Sensitized Solar Cell Containing a Cyclodextrin Layer Sun, 04 Oct 2015 11:22:01 +0000 We report the fabrication and characterization of a dye-sensitized solar cell containing a carboxymethyl-β-cyclodextrin sodium salt (CM-β-CD) layer and a noncarboxylated dye compound (tris(2,2′-bipyridyl)ruthenium(II)dichloride hexahydrate (Ru-dye)). The values of the incident photon-to-current conversion efficiency (IPCE) of the Ru-dye/CM-β-CD-containing device measured under 450 and 490 nm light irradiation were, respectively, 2.35% and 3.33%. The IPCE was due to the absorption of Ru-dye in ethanol solution. In contrast, the IPCE of the device that was prepared without the CM-β-CD layer measured under 450 nm irradiation was approximately three times smaller. Accordingly, the current findings demonstrate the application of a noncarboxylated dye compound in DSSCs incorporating a CM-β-CD layer. Tatsuya Takeshita, Takao Umeda, Noriaki Oonishi, and Michihiro Hara Copyright © 2015 Tatsuya Takeshita et al. All rights reserved. Perovskite Solar Cells: Potentials, Challenges, and Opportunities Sun, 04 Oct 2015 09:35:51 +0000 Heralded as a major scientific breakthrough of 2013, organic/inorganic lead halide perovskite solar cells have ushered in a new era of renewed efforts at increasing the efficiency and lowering the cost of solar energy. As a potential game changer in the mix of technologies for alternate energy, it has emerged from a modest beginning in 2012 to efficiencies being claimed at 20.1% in a span of just two years. This remarkable progress, encouraging at one end, also points to the possibility that the potential may still be far from being fully realized. With greater insight into the photophysics involved and optimization of materials and methods, this technology stands to match or even exceed the efficiencies for single crystal silicon solar cells. With thin film solution processability, applicability to flexible substrates, and being free of liquid electrolyte, this technology combines the benefits of Dye Sensitized Solar Cells (DSSCs), Organic Photovoltaics (OPVs), and thin film solar cells. In this review we present a brief historic perspective to this development, take a cognizance of the current state of the art, and highlight challenges and the opportunities. Muhammad Imran Ahmed, Amir Habib, and Syed Saad Javaid Copyright © 2015 Muhammad Imran Ahmed et al. All rights reserved. Sensitive Analysis for the Efficiency of a Parabolic Trough Solar Collector Based on Orthogonal Experiment Sun, 04 Oct 2015 09:10:21 +0000 A multitude of the researches focus on the factors of the thermal efficiency of a parabolic trough solar collector, that is, the optical-thermal efficiency. However, it is limited to a single or double factors for available system. The aim of this paper is to investigate the multifactors effect on the system’s efficiency in cold climate region. Taking climatic performance into account, an average outlet temperature of LS-2 collector has been simulated successfully by coupling SolTrace software with CFD software. Effects of different factors on instantaneous efficiency have been determined by orthogonal experiment and single factor experiment. After that, the influence degree of different factors on the collector instantaneous efficiency is obtained clearly. The results show that the order of effect extent for average maximal deviation of each factor is inlet temperature, solar radiation intensity, diameter, flow rate, condensation area, pipe length, and ambient temperature. The encouraging results will provide a reference for the exploitation and utilization of parabolic trough solar collector in cold climate region. Xiaoyan Liu, Jing Huang, and Qianjun Mao Copyright © 2015 Xiaoyan Liu et al. All rights reserved. Solar Thermal System Evaluation in China Sun, 04 Oct 2015 07:33:08 +0000 More than 581 solar thermal systems (STSs), 98 counties, and 47 renewable application demonstration cites in China need to be inspected by the end of 2015. In this study, the baseline for performance and economic evaluation of STSs are presented based on the site test data and related references. An index used to evaluate STSs was selected, and methods to acquire the parameters used to calculate the related index were set. The requirements for sensors for testing were specified. The evaluation method was applied to three systems and the result shows that the evaluation method is suitable for the evaluation of STSs in China. Xinyu Zhang, Wei Xu, Tao He, Shijun You, Yan Gao, Min Wang, and Bojia Li Copyright © 2015 Xinyu Zhang et al. All rights reserved. Correlation of Interfacial Transportation Properties of CdS/CdTe Heterojunction and Performance of CdTe Polycrystalline Thin-Film Solar Cells Thu, 01 Oct 2015 07:30:41 +0000 The light and dark output performances of CdS/CdTe solar cells made by close-spaced sublimation (CSS) were investigated to elucidate the transportation properties of carriers at CdS/CdTe heterojunction interface. It has been found that the interfacial transportation properties were relatively sensitive to variations of the characteristics of heterojunction due to the series resistance and shunting effects. For the high quality cell with 12.1% efficiency, narrow depletion region of ~1.1 microns and large electric field intensity of ~1.3 V/μm allow the sufficient energy-band bending close to CdS layer at CdS/CdTe heterojunction, which changes the carrier transportation mechanism from emission to diffusion and leads to the optimal rectifying characteristics with small dark saturation current density ~6.4 × 10−10 A/cm2. As a result, the schematic diagram of heterojunction band structure corresponding to various performances of solar cells has also been presented. Guanggen Zeng, Jingquan Zhang, Wenwu Wang, and Lianghuan Feng Copyright © 2015 Guanggen Zeng et al. All rights reserved. Enhanced Power Conversion Efficiency of P3HT : PC71BM Bulk Heterojunction Polymer Solar Cells by Doping a High-Mobility Small Organic Molecule Thu, 01 Oct 2015 06:51:05 +0000 The effect of molecular doping with TIPS-pentacene on the photovoltaic performance of polymer solar cells (PSCs) with a structure of ITO/ZnO/poly(3-hexylthiophene-2,5-diyl) (P3HT) : [6,6]-phenyl C71-butyric acid methyl ester (PC71BM) : TIPS-pentacene/MoOx/Ag was systematically investigated by adjusting TIPS-pentacene doping ratios ranged from 0.3 to 1.2 wt%. The device with 0.6 wt% TIPS-pentacene exhibited the enhanced short-circuit current and fill factor by 1.23 mA/cm2 and 7.8%, respectively, resulting in a maximum power conversion efficiency of 4.13%, which is one-third higher than that of the undoped one. The photovoltaic performance improvement was mainly due to the balanced charge carrier mobility, enhanced crystallinity, and matched cascade energy level alignment in TIPS-pentacene doped active layer, resulting in the efficient charge separation, transport, and collection. Hanyu Wang, Xiao Wang, Pu Fan, and Junsheng Yu Copyright © 2015 Hanyu Wang et al. All rights reserved. Synthesis and Optimization of Visible Light Active BiVO4 Photocatalysts for the Degradation of RhB Wed, 30 Sep 2015 05:56:58 +0000 Monoclinic BiVO4 powders were synthesized via a novel route using potassium metavanadate (KVO3) prepared by calcination of K2CO3 and V2O5 as a starting material and followed by hydrothermal treatment and were investigated for the degradation of Rhodamine B (RhB) under visible light irradiation. The synthesized BiVO4 particles were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), X-ray photoelectron spectroscopy (XPS), and UV-Visible (UV-Vis) light diffuse reflectance spectrophotometry. The synthesis produced pure monoclinic BiVO4 particles with multimorphological features containing flower-like, flake-ball, flake, cuboid-like, and plate-like shapes and exhibited strong absorption in the visible light range. The BiVO4 prepared via KVO3 possessed excellent photocatalytic activity for the degradation of RhB under visible light. The performance of this catalyst was found to be superior to other BiVO4 photocatalysts prepared via ammonium metavanadate (NH4VO3) using coprecipitation, combustion, and calcination methods reported in literature, respectively. Rong Ran, Joanne Gamage McEvoy, and Zisheng Zhang Copyright © 2015 Rong Ran et al. All rights reserved. Characteristics of Boron Decorated TiO2 Nanoparticles for Dye-Sensitized Solar Cell Photoanode Mon, 28 Sep 2015 09:21:59 +0000 Different boron weight percents on mixed-phase (anatase and rutile) TiO2 nanoparticles were synthesized to investigate structure morphology, defect states, luminescence properties, and energy conversion. The measured results indicate that boron doping of TiO2 both increases the crystallite size and rutile-phase percent in an anatase matrix. Decreasing the band gap by boron doping can extend the absorption to the visible region, while undoped TiO2 exhibits high UV absorption. Oxygen vacancy defects generated by boron ions reduce Ti+4 and affect electron transport in dye-sensitized solar cells. Excess electrons originating from the oxygen vacancies of doped TiO2 downward shift in the conduction band edge and prompt the transfer of photoelectrons from the conduction band of the rutile phase to the lower energy anatase trapping sites; they then separate charges to enhance the photocurrent and . Although the resistance of the electron recombination () between doped TiO2 photoanode and the electrolyte for the doped TiO2 sample is lower, a longer electron lifetime () of 19.7 ms with a higher electron density () of 2.1 × 1018 cm−3 contributes to high solar conversion efficiency. Ching-Yuan Ho, J. K. Lin, and Hong-Wen Wang Copyright © 2015 Ching-Yuan Ho et al. All rights reserved. Migration of Sn and Pb from Solder Ribbon onto Ag Fingers in Field-Aged Silicon Photovoltaic Modules Wed, 16 Sep 2015 09:16:37 +0000 We investigated the migration of Sn and Pb onto the Ag fingers of crystalline Si solar cells in photovoltaic modules aged in field for 6 years. Layers of Sn and Pb were found on the Ag fingers down to the edge of the solar cells. This phenomenon is not observed in a standard acceleration test condition for PV modules. In contrast to the acceleration test conditions, field aging subjects the PV modules to solar irradiation and moisture condensation at the interface between the solar cells and the encapsulant. The solder ribbon releases Sn and Pb via repeated galvanic corrosion and the Sn and Pb precipitate on Ag fingers due to the light-induced plating under solar irradiation. Wonwook Oh, Seongtak Kim, Soohyun Bae, Nochang Park, Sung-Il Chan, Yoonmook Kang, Hae-Seok Lee, and Donghwan Kim Copyright © 2015 Wonwook Oh et al. All rights reserved. A Combined Effect of Plasmon Energy Transfer and Recombination Barrier in a Novel TiO2/MgO/Ag Working Electrode for Dye-Sensitized Solar Cells Sun, 06 Sep 2015 09:38:25 +0000 Novel TiO2/MgO/Ag composite electrodes were applied as working electrodes of dye-sensitized solar cells (DSSCs). The TiO2/MgO/Ag composite films were prepared by dip coating method for MgO thin films and photoreduction method for Ag nanoparticles. The MgO film thicknesses and the Ag nanoparticle sizes were in ranges of 0.08–0.46 nm and 4.4–38.6 nm, respectively. The TiO2/MgO/Ag composite films were characterized by X-ray diffraction, scanning electron microscopy, and transmission electron microscopy. The TiO2/MgO/Ag composite electrodes were sensitized by immersing in a 0.3 mM of N719 dye solution and fabricated for conventional DSSCs. - characteristics of the TiO2/MgO/Ag DSSCs showed that the MgO film thickness of 0.1 nm and the Ag nanoparticle size of 4.4 nm resulted in maximum short circuit current density and efficiency of 8.6 mA/cm2 and 5.2%, respectively. Electrochemical Impedance Spectroscopy showed that such values of short circuit current density and efficiency were optimal values obtained from plasmon energy transfer by 4.4 nm Ag nanoparticles and recombination barrier by the ultrathin MgO film. Chanu Photiphitak, Pattana Rakkwamsuk, Pennapa Muthitamongkol, and Chanchana Thanachayanont Copyright © 2015 Chanu Photiphitak et al. All rights reserved. Electronic Structure Studies and Photocatalytic Properties of Cubic Bi1.5ZnNb1.5O7 Thu, 03 Sep 2015 11:14:09 +0000 The photocatalytic ability of cubic Bi1.5ZnNb1.5O7 (BZN) pyrochlore for the decolorization of an acid orange 7 (AO7) azo dye in aqueous solution under ultraviolet (UV) irradiation has been investigated for the first time. BZN catalyst powders prepared using low temperature sol-gel and higher temperature solid-state methods have been evaluated and their reaction rates have been compared. The experimental band gap energy has been estimated from the optical absorption edge and has been used as reference for theoretical calculations. The electronic band structure of BZN has been investigated using first-principles density functional theory (DFT) calculations for random, completely and partially ordered solid solutions of Zn cations in both the and sites of the pyrochlore structure. The nature of the orbitals in the valence band (VB) and the conduction band (CB) has been identified and the theoretical band gap energy has been discussed in terms of the DFT model approximations. Ganchimeg Perenlei, Jose A. Alarco, Peter C. Talbot, and Wayde N. Martens Copyright © 2015 Ganchimeg Perenlei et al. All rights reserved. Effect of Dopant Compensation on the Behavior of Dissolved Iron and Iron-Boron Related Complexes in Silicon Sun, 30 Aug 2015 12:59:59 +0000 The behavior of iron, iron-boron (FeB) pairs, and iron-boron-phosphorus (FeB-P) complexes has been studied in B-doped Czochralski silicon with phosphorus (P) compensation and compared with that in uncompensated material. The interstitial iron concentration has been measured at temperatures from 50 to 270°C. The apparent binding energy () of FeB in compensated silicon is (0.25 ± 0.03) eV, significantly lower than the (0.53 ± 0.02) eV in uncompensated silicon. Possible reasons for this reduction in binding energy are discussed by experimental and calculation methods. The results are important for understanding and controlling the behavior of Fe in compensated silicon. Xiaodong Zhu, Xuegong Yu, Peng Chen, Yong Liu, Jan Vanhellemont, and Deren Yang Copyright © 2015 Xiaodong Zhu et al. All rights reserved. Advanced Oxidation Processes for Wastewater Treatment 2014 Thu, 27 Aug 2015 06:34:19 +0000 Muruganandham Manickavachagam, Mika Sillanpaa, Meenakshisundaram Swaminathan, and Bashir Ahmmad Copyright © 2015 Muruganandham Manickavachagam et al. All rights reserved. Ozonation of Indigo Carmine Enhanced by Fe/Pimenta dioica L. Merrill Particles Wed, 26 Aug 2015 13:34:42 +0000 Green synthesis of metallic particles has become an economic way to improve and protect the environment by decreasing the use of toxic chemicals and eliminating dyes. The synthesis of metal particles is gaining more importance due to its simplicity, rapid rate of synthesis of particles, and environmentally friendly. The present work aims to report a novel and environmentally friendly method for the synthesis of iron particles using deoiled Pimenta dioica L. Merrill husk as support. The indigo carmine removal efficiency by ozonation and catalyzed ozonation is also presented. Synthesized materials were characterized by N2 physisorption and scanning electron microscopy (SEM/EDS). By UV-Vis spectrophotometry the removal efficiency of indigo carmine was found to be nearly 100% after only 20 minutes of treatment under pH 3 and with a catalyst loading of 1000 mgL−1. Analytical techniques such as determination of the total organic carbon content (TOC) and chemical oxygen demand (COD) showed that iron particles supported on deoiled Pimenta dioica L. Merrill husk can be efficiently employed to degrade indigo carmine and achieved a partial mineralization (conversion to CO2 and H2O) of the molecule. From the results can be inferred that the prepared biocomposite increases the hydroxyl radicals generation. Teresa Torres-Blancas, Gabriela Roa-Morales, Carlos Barrera-Díaz, Fernando Ureña-Nuñez, Julian Cruz-Olivares, Patricia Balderas-Hernandez, and Reyna Natividad Copyright © 2015 Teresa Torres-Blancas et al. All rights reserved. Water and Wastewater Disinfection with Peracetic Acid and UV Radiation and Using Advanced Oxidative Process PAA/UV Wed, 26 Aug 2015 07:31:54 +0000 The individual methods of disinfection peracetic acid (PAA) and UV radiation and combined process PAA/UV in water (synthetic) and sanitary wastewater were employed to verify the individual and combined action of these advanced oxidative processes on the effectiveness of inactivation of microorganisms indicators of fecal contamination E. coli, total coliforms (in the case of sanitary wastewater), and coliphages (such as virus indicators). Under the experimental conditions investigated, doses of 2, 3, and 4 mg/L of PAA and contact time of 10 minutes and 60 and 90 s exposure to UV radiation, the results indicated that the combined method PAA/UV provided superior efficacy when compared to individual methods of disinfection. Jeanette Beber de Souza, Fernanda Queiroz Valdez, Rhuan Felipe Jeranoski, Carlos Magno de Sousa Vidal, and Grasiele Soares Cavallini Copyright © 2015 Jeanette Beber de Souza et al. All rights reserved. Novel Electrochemical Treatment of Spent Caustic from the Hydrocarbon Industry Using Ti/BDD Tue, 25 Aug 2015 13:56:34 +0000 During the crude oil refining process, NaOH solutions are used to remove H2S, H2, and sulfur compounds from different hydrocarbon streams. The residues obtained are called “spent caustics.” These residues can be mixed with those obtained in other processes, adding to its chemical composition naphthenic acids and phenolic compounds, resulting in one of the most dangerous industrial residues. In this study, the use of electrochemical technology (ET), using BDD with Ti as substrate (Ti/BDD), is evaluated in electrolysis of spent caustic mixtures, obtained through individual samples from different refineries. In this way, the Ti/BDD’s capability of carrying out the electrochemical destruction of spent caustics in an acidic medium is evaluated having as key process a chemical pretreatment phase. The potential production of •OHs, as the main reactive oxygen species electrogenerated over Ti/BDD surface, was evaluated in HCl and H2SO4 through fluorescence spectroscopy, demonstrating the reaction medium’s influence on its production. The results show that the hydrocarbon industry spent caustics can be mineralized to CO2 and water, driving the use of ET and of the Ti/BDD to solve a real problem, whose potential and negative impact on the environment and on human health is and has been the environmental agencies’ main focus. Alejandro Medel, Erika Méndez, José L. Hernández-López, José A. Ramírez, Jesús Cárdenas, Roberto F. Frausto, Luis A. Godínez, Erika Bustos, and Yunny Meas Copyright © 2015 Alejandro Medel et al. All rights reserved. Determination of Biological Treatability Processes of Textile Wastewater and Implementation of a Fuzzy Logic Model Tue, 25 Aug 2015 13:36:28 +0000 This study investigated the biological treatability of textile wastewater. For this purpose, a membrane bioreactor (MBR) was utilized for biological treatment after the ozonation process. Due to the refractory organic contents of textile wastewater that has a low biodegradability capacity, ozonation was implemented as an advanced oxidation process prior to the MBR system to increase the biodegradability of the wastewater. Textile wastewater, oxidized by ozonation, was fed to the MBR at different hydraulic retention times (HRT). During the process, color, chemical oxygen demand (COD), and biochemical oxygen demand (BOD) removal efficiencies were monitored for 24-hour, 12-hour, 6-hour, and 3-hour retention times. Under these conditions, 94% color, 65% COD, and 55% BOD removal efficiencies were obtained in the MBR system. The experimental outputs were modeled with multiple linear regressions (MLR) and fuzzy logic. MLR results suggested that color removal is more related to COD removal relative to BOD removal. A surface map of this issue was prepared with a fuzzy logic model. Furthermore, fuzzy logic was employed to the whole modeling of the biological system treatment. Determination coefficients for COD, BOD, and color removal efficiencies were 0.96, 0.97, and 0.92, respectively. Harun Akif Kabuk, Yasar Avsar, S. Levent Kuzu, Fatih Ilhan, and Kubra Ulucan Copyright © 2015 Harun Akif Kabuk et al. All rights reserved. Removal of Polyvinyl Alcohol in Aqueous Solutions Using an Innovative Paired Photoelectrochemical Oxidative System in a Divided Electrochemical Cell Tue, 25 Aug 2015 12:35:25 +0000 This study evaluates the performance of an innovative paired photoelectrochemical oxidative system fabricated in our laboratory to determine the removal efficiency of polyvinyl alcohol (PVA) in aqueous solutions. An innovative paired photoelectrochemical oxidative system employed metal redox mediators with high redox potential for anodic oxidation (MEO process) and UV assisted photoelectrochemical oxidation (PEO process) for cathodic oxidation in a divided electrochemical cell. Several parameters were investigated to characterize the removal efficiency of PVA, such as the current density, initial Ce(III) concentration, nitric acid concentration, oxygen flow rate, and UV irradiation intensity. The effects of these parameters on the specific energy consumption were also investigated. Additionally, the conversion yield of Ce(IV) concentration and the electrogeneration of H2O2 were calculated in this study. The optimum current density, initial Ce(III) concentration, nitric acid concentration, oxygen flow rate, and UV irradiation intensity were found to be 3 mA cm−2, 0.01 M, 0.3 M, 500 cm3 min−1, and 1.2 mW cm−2, respectively. The synergistic effect of combination process of MEO and PEO would be as a promising alternative for the removal efficiency of PVA. Kai-Yu Huang, Chih-Ta Wang, Wei-Lung Chou, and Chi-Min Shu Copyright © 2015 Kai-Yu Huang et al. All rights reserved. Design, Development, and Analysis of a Densely Packed 500x Concentrating Photovoltaic Cell Assembly on Insulated Metal Substrate Thu, 20 Aug 2015 11:53:09 +0000 The paper presents a novel densely packed assembly for high concentrating photovoltaic applications, designed to fit 125x primary and 4x secondary reflective optics. This assembly can accommodate 144 multijunction cells and is one of the most populated modules presented so far. Based on the thermal simulation results, an aluminum-based insulated metal substrate has been used as baseplate; this technology is commonly exploited for Light Emitting Diode applications, due to its optimal thermal management. The original outline of the conductive copper layer has been developed to minimize Joule losses by reducing the number of interconnections among the cells in series. Oversized Schottky diodes have been employed for bypassing purposes. The whole design fits the IPC-2221 requirements. The plate has been manufactured using standard electronic processes and then characterized through an indoor test and the results are here presented and commented on. The assembly achieves a fill factor above 80% and an efficiency of 29.4% at 500x, less than 2% lower than that of a single cell commercial receiver. The novel design of the conductive pattern is conceived to decrease the power losses and the deployment of an insulated metal substrate represents an improvement towards the awaited cost-cutting for high concentrating photovoltaic technologies. Leonardo Micheli, Nabin Sarmah, K. S. Reddy, Xichun Luo, and Tapas K. Mallick Copyright © 2015 Leonardo Micheli et al. All rights reserved. Thermal Analysis of Direct Liquid-Immersed Solar Receiver for High Concentrating Photovoltaic System Wed, 12 Aug 2015 06:40:16 +0000 Concentrator solar cells that operate at high solar concentration level must be cooled. In this paper, direct liquid immersion cooling of triple-junction solar cells (InGaP/InGaAs/Ge) is proposed as a heat dissipation solution for dense-array high concentrating photovoltaic (HCPV) systems. The advantages of triple-junction CPV cells immersed in a circulating dielectric liquid and dish HCPV technology are integrated into a CPV system to improve the system electrical conversion efficiency. An analytical model for the direct liquid-immersed solar receiver with triple-junction CPV cells is presented. The main outputs of the model are the components temperatures of the receiver and the system electrical efficiency. The influence of concentration factor, mass flow rate, and inlet liquid temperature on the operating temperature of the triple-junction CPV cells and the system electrical conversion efficiency are discussed. It is shown that the system electrical conversion efficiency is very high for a wide range of operating conditions. The three operating parameters have a major effect on the operating temperature of the triple-junction CPV cells and, by extension, system output power. The flow rate selection should match concentration factor to keep the triple-junction CPV cells temperature lower and increase the electrical conversion efficiency of the dense-array HCPV system. Xinyue Han, Qian Wang, Jun Zheng, and Jian Qu Copyright © 2015 Xinyue Han et al. All rights reserved. Construction and Optical Testing of Inflatable Membrane Mirror Using Structured Light Technique Sun, 09 Aug 2015 07:11:03 +0000 Construction and characterization of an inflatable mirror prototype made out of flexible polymeric membranes are being presented. Surfaces were curved by imposing a slight excess of air pressure. Lightweighted, lowcost, and commercially available materials were selected in order to produce solar concentration elements at competitive prices. In this sense, large-area, image-forming mirrors with low optical acuity were achieved by concentration purposes. Optical characterization of the mirror’s shape at a given pressure or curvature radius was done by means of a structuredlight technique with a resolution of 0.1 mm finding a conical shape acquired by the inflated mirror as the best approximation. Concentration ratio achieved for a focal length of 5068 mm was of 25.1 suns, making a promising approach for lowering initial investment costs in applications such as hot-water, parabolic dish with Stirling engines, or concentrated photovoltaic electricity generation. Felipe Patiño-Jiménez, Yuri Nahmad-Molinari, Víctor Iván Moreno-Oliva, Fátima De Los Santos-García, and Agustin Santiago-Alvarado Copyright © 2015 Felipe Patiño-Jiménez et al. All rights reserved. Recent Research Progress in Solar Thermal Conversion Theory and Applications Tue, 04 Aug 2015 13:33:37 +0000 Gang Pei, Yuehong Su, Sauro Filippeschi, and Hongfei Zheng Copyright © 2015 Gang Pei et al. All rights reserved. Performance Investigation and Structure Optimization of a Flat Dual-Function Solar Collector Tue, 04 Aug 2015 11:37:55 +0000 The performance of a dual-function solar collector (DFSC) that can work as either water heater or air heater depending on seasonal requirement is investigated via both experimental and numerical approaches in this paper. The numerical results are well consistent with the experimental results. Daily efficiency of the thermosiphon system with DFSC is more than 55% in water heating mode and the instantaneous air heating efficiency of the collector reaches 60%. The effects of inner parameters on the thermal efficiency of the collector are analyzed by numerical simulations of the operation of DFSC in two working modes. It is found that the depths of the two air channels in DFSC have an optimal range suitable for both working modes. The thickness of back insulation should be no less than 0.06 m to prevent heat loss via backboard, and the diameter and number of copper tubes show notable effect on the efficiency of DFSC in water heating mode but slight effect in air heating mode. Jinwei Ma, Haitao Wang, Yanping Wang, Wei Sun, and Jie Ji Copyright © 2015 Jinwei Ma et al. All rights reserved. A Study on Thermal Performance of a Novel All-Glass Evacuated Tube Solar Collector Manifold Header with an Inserted Tube Tue, 04 Aug 2015 11:30:38 +0000 A novel all-glass evacuated tube collector manifold header with an inserted tube is proposed in this paper which makes water in all-glass evacuated solar collector tube be forced circulated to improve the performance of solar collector. And a dynamic numerical model was presented for the novel all-glass evacuated tube collector manifold header water heater system. Also, a test rig was built for model validation and comparison with traditional all-glass evacuated tube collector. The experiment results show that the efficiency of solar water heater with a novel collector manifold header is higher than traditional all-glass evacuated tube collector by about 5% and the heat transfer model of water heater system is valid. Based on the model, the relationship between the average temperature of water tank and inserted tube diameter (water mass flow) has been studied. The results show that the optimized diameter of inserted tube is 32 mm for the inner glass with the diameter of 47 mm and the water flow mass should be less than 1.6 Kg/s. Jichun Yang, Qingyang Jiang, Jingxin Hou, and Chenglong Luo Copyright © 2015 Jichun Yang et al. All rights reserved.