International Journal of Photoenergy The latest articles from Hindawi © 2017 , Hindawi Limited . All rights reserved. Influence of the Porosity of the TiO2 Film on the Performance of the Perovskite Solar Cell Wed, 01 Feb 2017 06:41:17 +0000 The structure of mesoporous TiO2 (mp-TiO2) films is crucial to the performance of mesoporous perovskite solar cells (PSCs). In this study, we fabricated highly porous mp-TiO2 films by doping polystyrene (PS) spheres in TiO2 paste. The composition of the perovskite films was effectively improved by modifying the mass fraction of the PS spheres in the TiO2 paste. Due to the high porosity of the mp-TiO2 film, PbI2 and CH3NH3I could sufficiently infiltrate into the network of the mp-TiO2 film, which ensured a more complete transformation to CH3NH3PbI3. The surface morphology of the mp-TiO2 film and the photoelectric performance of the perovskite solar cells were investigated. The results showed that an increase in the porosity of the mp-TiO2 film resulted in an improvement in the performance of the PSCs. The best device with the optimized mass fraction of 1.0 wt% PS in TiO2 paste exhibited an efficiency of 12.69%, which is 25% higher than the efficiency of the PSCs without PS spheres. Xiaodan Sun, Jia Xu, Li Xiao, Jing Chen, Bing Zhang, Jianxi Yao, and Songyuan Dai Copyright © 2017 Xiaodan Sun et al. All rights reserved. Investigation on the Synthesis and Photocatalytic Property of Uranyl Complexes of the -Diketonates Biscatecholamide Ligand Sun, 29 Jan 2017 08:08:05 +0000 A series of uranyl complexes have been synthesized by reacting hexadentate ligands CH2[COO (CH2)nCAM; , 3, 4]2 [CAM = 2,3-Ph(OH)2CONH] containing the catecholamide (CAM) group and β-diketonates framework with uranyl nitrate. They were characterized by FTIR, UV-vis, 1H NMR, XPS, TGA, and elemental analysis. The analysis revealed that oxygen atom of β-diketonate did not bind to uranyl ion in complexes 1–3. The photocatalytic degradation properties of the target complexes for degradation of rhodamine B (RhB) were investigated. The result indicated that approximately 74%, 71%, and 67% RhB were degraded in the presence of complexes 1–3 after about 210 min, respectively. Consequently, complexes 1–3 have excellent photocatalytic degradation property. Qingchun Zhang, Bo Jin, Rufang Peng, Xiaofang Wang, Zhaotao Shi, Qiangqiang Liu, Shan Lei, and Hua Liang Copyright © 2017 Qingchun Zhang et al. All rights reserved. Copper Sulfide Catalyzed Porous Fluorine-Doped Tin Oxide Counter Electrode for Quantum Dot-Sensitized Solar Cells with High Fill Factor Thu, 26 Jan 2017 12:28:12 +0000 The performance of quantum dot-sensitized solar cell (QDSSC) is mainly limited by chemical reactions at the interface of the counter electrode. Generally, the fill factor (FF) of QDSSCs is very low because of large charge transfer resistance at the interface between the counter electrode and electrolyte solution containing redox couples. In the present research, we demonstrate the improvement of the resistance by optimization of surface area and amount of catalyst of the counter electrode. A facile chemical synthesis was used to fabricate a composite counter electrode consisting of fluorine-doped tin oxide (FTO) powder and CuS nanoparticles. The introduction of a sputtered gold layer at the interface of the porous-FTO layer and underlying glass substrate also markedly reduced the resistance of the counter electrode. As a result, we could reduce the charge transfer resistance and the series resistance, which were 2.5 [Ω] and 6.0 [Ω], respectively. This solar cell device, which was fabricated with the presently designed porous-FTO counter electrode as the cathode and a PbS-modified electrode as the photoanode, exhibited a FF of 58%, which is the highest among PbS-based QDSSCs reported to date. Satoshi Koyasu, Daiki Atarashi, Etsuo Sakai, and Masahiro Miyauchi Copyright © 2017 Satoshi Koyasu et al. All rights reserved. Performance Enhancement of Dye-Sensitized Solar Cells Using a Natural Sensitizer Tue, 24 Jan 2017 05:58:32 +0000 Dye-sensitized solar cells (DSSCs) based on natural sensitizers have become a topic of significant research because of their urgency and importance in the energy conversion field and the following advantages: ease of fabrication, low-cost solar cell, and usage of nontoxic materials. In this study, the chlorophyll extracted from papaya leaves was used as a natural sensitizer. Dye molecules were adsorbed by TiO2 nanoparticle surfaces when submerged in the dye solution for 24 h. The concentration of the dye solution influences both the amount of dye loading and the DSSC performance. The amount of adsorbed dye molecules by TiO2 nanoparticle was calculated using a desorption method. As the concentration of dye solution was increased, the dye loading capacity and power conversion efficiency increased. Above 90 mM dye solution concentration, however, the DSSC efficiency decreased because dye precipitated on the TiO2 nanostructure. These characteristics of DSSCs were analyzed under the irradiation of 100 mW/cm2. The best performance of DSSCs was obtained at 90 mM dye solution, with the values of , ,  FF, and efficiency of DSSCs being 0.561 V, 0.402 mA/cm2, 41.65%, and 0.094%, respectively. Zainal Arifin, Sudjito Soeparman, Denny Widhiyanuriyawan, and Suyitno Suyitno Copyright © 2017 Zainal Arifin et al. All rights reserved. Mismatch Based Diagnosis of PV Fields Relying on Monitored String Currents Mon, 16 Jan 2017 00:00:00 +0000 This paper presents a DC side oriented diagnostic method for photovoltaic fields which operates on string currents previously supplied by an appropriate monitoring system. The relevance of the work relies on the definition of an effective and reliable day-by-day target for the power that every string of the field should have produced. The procedure is carried out by comparing the instantaneous power produced by all solar strings having the same orientation and by attributing, as producible power for all of them, the maximum value. As figure of merit, the difference between the maximum allowed energy production (evaluated as the integral of the power during a defined time interval) and the energy actually produced by the strings is defined. Such a definition accounts for both weather and irradiance conditions, without needing additional sensors. The reliability of the approach was experimentally verified by analyzing the performance of two medium size solar fields that were monitored over a period of four years. Results allowed quantifying energy losses attributable to underperforming solar strings and precisely locating their position in the field. Pierluigi Guerriero, Luigi Piegari, Renato Rizzo, and Santolo Daliento Copyright © 2017 Pierluigi Guerriero et al. All rights reserved. Monitoring, Diagnosis, and Power Forecasting for Photovoltaic Fields: A Review Wed, 11 Jan 2017 12:54:18 +0000 A wide literature review of recent advance on monitoring, diagnosis, and power forecasting for photovoltaic systems is presented in this paper. Research contributions are classified into the following five macroareas: (i) electrical methods, covering monitoring/diagnosis techniques based on the direct measurement of electrical parameters, carried out, respectively, at array level, single string level, and single panel level with special consideration to data transmission methods; (ii) data analysis based on artificial intelligence; (iii) power forecasting, intended as the ability to evaluate the producible power of solar systems, with emphasis on temporal horizons of specific applications; (iv) thermal analysis, mostly with reference to thermal images captured by means of unmanned aerial vehicles; (v) power converter reliability especially focused on residual lifetime estimation. The literature survey has been limited, with some exceptions, to papers published during the last five years to focus mainly on recent developments. S. Daliento, A. Chouder, P. Guerriero, A. Massi Pavan, A. Mellit, R. Moeini, and P. Tricoli Copyright © 2017 S. Daliento et al. All rights reserved. Silver/Carbon Codoped Titanium Dioxide Photocatalyst for Improved Dye Degradation under Visible Light Wed, 11 Jan 2017 00:00:00 +0000 Herein, we report the synthesis of quartz supported TiO2 photocatalysts codoped with carbon and silver through the hydrolysis of titanium tetrachloride followed by calcination at 500°C. The prepared samples were characterized by UV-Vis diffuse reflectance spectroscopy, high resolution scanning electron microscopy (HRSEM), Raman spectroscopy, thermogravimetric analysis (TGA), X-ray photoelectron spectroscopy (XPS), and X-ray diffraction (XRD). Codoping of TiO2 with Ag and carbon resulted in an increase in the surface area of the photocatalyst and altered the ratio of the anatase to rutile phase. The absorption edge of all the doped TiO2 photocatalysts redshifted and the band gap was reduced. The lowest band gap of 1.95 eV was achieved by doping with 0.5% Ag. Doping TiO2 using carbon as the only dopant resulted in a quartz supported photocatalyst that showed greater photocatalytic activity towards methyl orange than undoped TiO2 and also all codoped TiO2 photocatalysts under visible light irradiation. P. Nyamukamba, L. Tichagwa, S. Mamphweli, and L. Petrik Copyright © 2017 P. Nyamukamba et al. All rights reserved. Enhanced Efficiency of PTB7 : PC61BM Organic Solar Cells by Adding a Low Efficient Polymer Donor Wed, 11 Jan 2017 00:00:00 +0000 Ternary blend polymer solar cells combining two electron-donor polymers, poly[4,8-bis[(2-ethylhexyl)oxy]benzo[1,2-b:4,5-b′]dithiophene-2,6-diyl][3-fluoro-2-[(2-ethylhexyl)carbonyl]thieno[3,4-b]thiophenediyl] (PTB7) and poly[2,5-bis(3-dodecylthiophen-2-yl)thieno[3,2-b]thiophene] (pBTTT) and [6,6]-phenyl-C61-butyric acid methyl ester (PC61BM), as electron-acceptor, were fabricated. The power conversion efficiency of the ternary cells was enhanced by 18%, with respect to the reference binary cells, for a blend composition with 25% (wt%) of pBTTT in the polymers content. The optimized device performance was related to the blend morphology, nonrevealing pBTTT aggregates, and improved charge extraction within the device. Joana Farinhas, Ricardo Oliveira, Quirina Ferreira, Jorge Morgado, and Ana Charas Copyright © 2017 Joana Farinhas et al. All rights reserved. Effect of Modulating Spin-Coating Rate of TiO2 Precursor for Mesoporous Layer on Hysteresis of Solar Cells with Polar CH3NH3PbI3 Perovskite Thin Film Tue, 10 Jan 2017 12:35:08 +0000 Compared with the crystalline Si solar cells, the - characteristics of CH3NH3PbI3 perovskite solar cells are different under forward and reverse scan, and the CH3NH3PbI3 film exhibits some polarization properties. To explore those performances of the mesoporous TiO2 layer based perovskite solar cells, we focus on the effect of modulating the spin-coating rate of the TiO2 precursor for mesoporous layer on - hysteresis of solar cells with the polar film by - curves, atomic force microscopy topographic images, and piezoresponse force microscopy phase images. Firstly, the AFM images illustrate that the polarization behaviors exist and the deformation scale is large at the corresponding position when the DC bias voltage increases. Secondly, it is suggested that the polar films which applied the positive DC biases voltage show a tendency to 0° phase angle, while the polar films which applied the negative DC biases voltage show a tendency to −180° phase angle. Thirdly, a weak polar hysteresis loop relation for CH3NH3PbI3 film was observed. Finally, the hysteresis index for the 1500 rpm mesostructured solar cell shows relatively low - hysteresis compared with the 3000 rpm mesostructured and the planar-structured solar cell. Our experimental results bring novel routes for reducing the hysteresis and investigating the polar nature for CH3NH3PbI3 material. Qi Li, Xiaoping Zou, Yuanyuan Li, Yaxian Pei, Shuangxiong Zeng, and Dongdong Guo Copyright © 2017 Qi Li et al. All rights reserved. Synergetic Enhancement of the Photocatalytic Activity of TiO2 with Visible Light by Sensitization Using a Novel Push-Pull Zinc Phthalocyanine Tue, 10 Jan 2017 11:27:00 +0000 A new one-pot synthesis of a novel A3B-type asymmetric zinc phthalocyanine (AZnPc) was developed. The phthalocyanine complex was characterized unambiguously and used to prepare a TiO2 hybrid photocatalyst to enhance its photocatalytic activity in the visible range. Different compositions of the phthalocyanine dye were tested in order to find the optimum amount of sensitizer to get the highest activity during the photocatalytic tests. The hybrid photocatalyst was characterized by UV-Vis diffuse reflectance (DRS) and Fourier transform infrared spectroscopy (FT-IR) and its photocatalytic activity was compared with that of the individual components considering the effects of sensitization on their efficiency to degrade Rhodamine B as a model reaction. A synergic improvement of the photocatalytic activity for the hybrid system was explained in terms of an improved electron injection from the photo-activated phthalocyanine to the TiO2. Considering the structural features of the phthalocyanine sensitizer and their effect on aggregation, some mechanistic aspects of its binding to TiO2 are suggested to account for the photocatalytic activity enhancement. Finally, the inhibitory effect on the sprouting of chia seeds (Salvia hispanica) was evaluated in order to test the toxicity of the water effluent obtained after the photodegradation process. According to our growth inhibition assays, it was found that the Rh-B degradation by-products do not lead to an acute toxicity. A. Luna-Flores, M. A. Valenzuela, J. A. Luna-López, A. D. Hernández de la Luz, L. C. Muñoz-Arenas, M. Méndez-Hernández, and J. L. Sosa-Sánchez Copyright © 2017 A. Luna-Flores et al. All rights reserved. Sprayed and Spin-Coated Multilayer Antireflection Coating Films for Nonvacuum Processed Crystalline Silicon Solar Cells Mon, 02 Jan 2017 14:43:00 +0000 Using the simple and cost-effective methods, spin-coated ZrO2-polymer composite/spray-deposited TiO2-compact multilayer antireflection coating film was introduced. With a single TiO2-compact film on the surface of a crystalline silicon wafer, 5.3% average reflectance (the reflectance average between the wavelengths of 300 nm and 1100 nm) was observed. Reflectance decreased further down to 3.3% after forming spin-coated ZrO2 on the spray-deposited TiO2-compact film. Silicon solar cells were fabricated using CZ-Si p-type wafers in three sets: (1) without antireflection coating (ARC) layer, (2) with TiO2-compact ARC film, and (3) with ZrO2-polymer composite/TiO2-compact multilayer ARC film. Conversion efficiency of the cells improved by a factor of 0.8% (from 15.19% to 15.88%) owing to the multilayer ARC. was improved further by 2 mA cm−2 (from 35.3 mA cm−2 to 37.2 mA cm−2) when compared with a single TiO2-compact ARC. Abdullah Uzum, Masashi Kuriyama, Hiroyuki Kanda, Yutaka Kimura, Kenji Tanimoto, Hidehito Fukui, Taichiro Izumi, Tomitaro Harada, and Seigo Ito Copyright © 2017 Abdullah Uzum et al. All rights reserved. Study on the Optimizing Operation of Exhaust Air Heat Recovery and Solar Energy Combined Thermal Compensation System for Ground-Coupled Heat Pump Sun, 01 Jan 2017 09:25:37 +0000 This study proposed an exhaust air heat recovery and solar energy combined thermal compensation system (ESTC) for ground-coupled heat pumps. Based on the prediction of the next day’s exhaust air temperature and solar irradiance, an optimized thermal compensation (OTC) method was developed in this study as well, in which the exhaust air heat recovery compensator and solar energy compensator in the ESTC system run at high efficiency throughout various times of day. Moreover, a modified solar term similar days group (STSDG) method was proposed to improve the accuracy of solar irradiance prediction in hazy weather. This modified STSDG method was based on air quality forecast and AQI (air quality index) correction factors. Through analyzing the operating parameters and the simulation results of a case study, the ESTC system proved to have good performance and high efficiency in eliminating the heat imbalance by using the OTC method. The thermal compensation quantity per unit energy consumption (TEC) of ESTC under the proposed method was 1.25 times as high as that under the traditional operation method. The modified STSDG method also exhibited high accuracy. For the accumulated solar irradiance of the four highest daily radiation hours, the monthly mean absolute percentage error (MAPE) between the predicted values and the measured values was 6.35%. Kuan Wang, Nianping Li, Jinqing Peng, and Yingdong He Copyright © 2017 Kuan Wang et al. All rights reserved. Enhanced Photocatalytic Degradation and Mineralization of Furfural Using UVC/TiO2/GAC Composite in Aqueous Solution Thu, 29 Dec 2016 07:09:10 +0000 Titanium dioxide nanoparticles were immobilized on granular activated carbon (GAC) as a porous and low-density support for photocatalytic degradation of furfural. The TiO2/GAC composite was synthetized using the simple sol-gel method and fully characterized. The effects of the operational parameters of furfural concentration (200–700 mg/L), initial pH (2–12), TiO2/GAC composite dosage (1–3.5 g/L), and irradiation time (20–120 min) were studied. The synthetized TiO2/GAC composite exhibited a total pore volume of 0.13 cm3/g and specific surface area of 35.91 m2/g. Removal efficiency of up to 95% was observed at initial pH of 10, TiO2/GAC dosage of 2.5 g/L, irradiation time of 80 min, and initial furfural concentration of 500 mg/L. The photocatalyst could be reused at least four consecutive times with a mere 2% decrease in furfural removal efficiency. Mineralization efficiency of 94% was obtained within 80 min. Pseudo-first-order kinetics best fit the photocatalytic degradation of furfural under experimental conditions. Bahram Ghasemi, Bagher Anvaripour, Sahand Jorfi, and Neematollah Jaafarzadeh Copyright © 2016 Bahram Ghasemi et al. All rights reserved. Preparation of Titanium Dioxide Nanoparticles Immobilized on Polyacrylonitrile Nanofibres for the Photodegradation of Methyl Orange Tue, 27 Dec 2016 09:44:31 +0000 Herein, we describe the synthesis of titanium dioxide (TiO2) nanoparticles by the hydrolysis and condensation of titanium tetrachloride. The resulting nanoparticles were immobilized on polyacrylonitrile (PAN) based nanofibres by an electrospinning technique in order to allow simple isolation and reuse of titania semiconductor photocatalyst. The composite nanofibres were heat treated to convert the polymer nanofibres to carbon nanofibres and to convert amorphous TiO2 to crystalline TiO2. X-ray diffraction (XRD) analysis showed that the rutile phase was the major phase and the equatorial peaks of PAN disappeared after heat treatment at 600°C. Transmission electron microscopy (TEM) and scanning electron microscopy (SEM) analysis confirmed that some TiO2 nanoparticles were encapsulated whereas some were surface residing on the electrospun nanofibres. The TiO2 nanoparticles were found to lower the cyclization temperature of PAN as indicated by differential scanning colorimetry (DSC) and differential thermal analysis (DTA). Photocatalytic studies on the degradation of methyl orange dye under UV light irradiation showed that composite nanofibres were capable of degrading organic contaminants in water. The carbon nanofibres with surface residing titanium dioxide nanoparticles (TiO2/CNF-SR) showed the highest photocatalytic activity (59.35% after 210 minutes) due to direct contact between the TiO2 photocatalyst and methyl orange. Pardon Nyamukamba, Omobola Okoh, Lilian Tichagwa, and Corinne Greyling Copyright © 2016 Pardon Nyamukamba et al. All rights reserved. Impedance Spectroscopic Investigation of the Degraded Dye-Sensitized Solar Cell due to Ageing Tue, 06 Dec 2016 14:18:50 +0000 This paper investigates the effect of ageing on the performance of dye-sensitized solar cells (DSCs). The electrical characterization of fresh and degraded DSCs is done under AM1.5G spectrum and the current density-voltage (J-V) characteristics are analyzed. Short circuit current density () decreases significantly whereas a noticeable increase in open circuit voltage is observed. These results have been further investigated electroanalytically using electrochemical impedance spectroscopy (EIS). An increase in net resistance results in a lower for the degraded DSC. This decrease in current is mainly due to degradation of TiO2-dye interface, which is observed from light and dark J-V characteristics and is further confirmed by EIS measurements. A reduction in the chemical capacitance of the degraded DSC is observed, which is responsible for the shifting of Fermi level with respect to conduction band edge that further results in an increase of open circuit voltage for the degraded DSC. It is also confirmed from EIS that the degradation leads to a better contact formation between the electrolyte and Pt electrode, which improves the fill factor of the DSC. But the recombination throughout the DSC is found to increase along with degradation. This study suggests that the DSC should be used under low illumination conditions and around room temperature for a longer life. Parth Bhatt, Kavita Pandey, Pankaj Yadav, Brijesh Tripathi, and Manoj Kumar Copyright © 2016 Parth Bhatt et al. All rights reserved. Analysis on Photovoltaic Energy-Assisted Drying of Green Peas Mon, 05 Dec 2016 08:36:36 +0000 A photovoltaic energy-assisted industrial dryer has been analyzed. The dryer has been tested in various weather and working conditions with 3 kg of green peas from 75.6% initial moisture content to 20% final moisture content (w.b.). The effect of various drying air temperatures at three levels (40, 50, and 60°C) and two distinct air velocities (3 m/s and 4 m/s) was examined. Drying performance was assessed with regard to criteria including drying kinetics, specific and total energy consumption, and color and rehydration ratio. The results have proved that total drying duration reduces as air velocity rate and drying air temperature raise. Relying upon the drying durations, the generation performances of photovoltaic panels were between 5.261 and 3.953 W. On the other part, energy consumptions of dryer were between 37.417 and 28.111 W. The best specific energy consumption was detected in 50°C at 3 m/s for 600 minutes with 7.616 kWh/kg. All drying conditions caused darkening as color parameters. Rehydration assays have showed that rehydrated green peas attained higher capacity with raised air temperature and air velocity. Onur Taşkın, Nazmi İzli, and Ali Vardar Copyright © 2016 Onur Taşkın et al. All rights reserved. ZnSnS3: Structure Prediction, Ferroelectricity, and Solar Cell Applications Sun, 04 Dec 2016 14:23:41 +0000 The rapid growth of the solar energy industry is driving a strong demand for high performance, efficient photoelectric materials. In particular, ferroelectrics composed of earth-abundant elements may be useful in solar cell applications due to their large internal polarization. Unfortunately, wide band gaps prevent many such materials from absorbing light in the visible to mid-infrared range. Here, we address the band gap issue by investigating the effects of substituting sulfur for oxygen in the perovskite structure ZnSnO3. Using evolutionary methods, we identify the stable and metastable structures of ZnSnS3 and compare them to those previously characterized for ZnSnO3. Our results suggest that the most stable structure of ZnSnS3 is the monoclinic structure, followed by the metastable ilmenite and lithium niobate structures. The latter structure is highly polarized, possessing a significantly reduced band gap of 1.28 eV. These desirable characteristics make it a prime candidate for solar cell applications. Radi A. Jishi and Marcus A. Lucas Copyright © 2016 Radi A. Jishi and Marcus A. Lucas. All rights reserved. Energy Conversion and Transmission Characteristics Analysis of Ice Storage Air Conditioning System Driven by Distributed Photovoltaic Energy System Thu, 01 Dec 2016 07:26:02 +0000 In order to reduce the investment and operation cost of distributed PV energy system, ice storage technology was introduced to substitute batteries for solar energy storage. Firstly, the ice storage air conditioning system (ISACS) driven by distributed photovoltaic energy system (DPES) was proposed and the feasibility studies have been investigated in this paper. And then, the theoretical model has been established and experimental work has been done to analyze the energy coupling and transferring characteristics in light-electricity-cold conversion process. In addition, the structure optimization analysis was investigated. Results revealed that energy losses were high in ice making process of ice slide maker with only 17.38% energy utilization efficiency and the energy efficiency and exergy efficiency of ISACS driven by DPES were 5.44% and 67.30%, respectively. So the immersed evaporator and cointegrated exchanger were adopted for higher energy utilization efficiency and better financial rewards in structure optimization. The COP and exergy efficiency of ice maker can be increased to 1.48 and 81.24%, respectively, after optimization and the energy utilization efficiency of ISACS driven by DPES could be improved 2.88 times. Moreover, ISACS has the out-of-the-box function of ordinary air conditioning system. In conclusion, ISACS driven by DPES will have good application prospects in tropical regions without power grid. Yongfeng Xu, Ming Li, and Reda Hassanien Emam Hassanien Copyright © 2016 Yongfeng Xu et al. All rights reserved. Influence of Anodization Time on Photovoltaic Performance of DSSCs Based on TiO2 Nanotube Array Mon, 28 Nov 2016 14:24:31 +0000 Highly ordered TiO2 nanotube arrays (TNT arrays) were fabricated by two-step anodization process. In order to further improve the performance of DSSCs, TNT arrays were optimized by changing the anodization conditions to meet the requirements of high-performance photoanode. The photoelectric conversion properties of DSSCs based on P25/TNT arrays double-layer film with different anodization time were investigated and compared. The results show that the conversion efficiency of 4.20% was achieved in double-layer photoanode at 18 h, with an open-circuit voltage () of 0.65 V and short-circuit current density () of 9.98 mA cm−2. Jinghua Hu, Shiwu Hu, Yingping Yang, Shengqiang Tong, Jiejie Cheng, Mengwei Chen, Li Zhao, and Jinxia Duan Copyright © 2016 Jinghua Hu et al. All rights reserved. Optical Simulation and Experimental Verification of a Fresnel Solar Concentrator with a New Hybrid Second Optical Element Mon, 14 Nov 2016 06:24:34 +0000 Fresnel solar concentrator is one of the most common solar concentrators in solar applications. For high Fresnel concentrating PV or PV/T systems, the second optical element (SOE) is the key component for the high optical efficiency at a wider deflection angle, which is important for overcoming unavoidable errors from the tacking system, the Fresnel lens processing and installment technology, and so forth. In this paper, a new hybrid SOE was designed to match the Fresnel solar concentrator with the concentration ratio of 1090x. The ray-tracing technology was employed to indicate the optical properties. The simulation outcome showed that the Fresnel solar concentrator with the new hybrid SOE has a wider deflection angle scope with the high optical efficiency. Furthermore, the flux distribution with different deviation angles was also analyzed. In addition, the experiment of the Fresnel solar concentrator with the hybrid SOE under outdoor condition was carried out. The verifications from the electrical and thermal outputs were all made to analyze the optical efficiency comprehensively. The optical efficiency resulting from the experiment is found to be consistent with that from the simulation. Guiqiang Li and Yi Jin Copyright © 2016 Guiqiang Li and Yi Jin. All rights reserved. An Improved PV Output Forecasting Model by Using Weight Function: A Case Study in Cambodia Sun, 13 Nov 2016 07:16:05 +0000 This paper proposes a new concept to improve accuracy of PV forecasting model. The model was implemented by MATLAB/Simulink software using solar irradiance and module temperature as measurement parameters for calculation. The model was developed by single-diode equivalent circuits (5-p model) for simulated PV module power output and compared with other software programs for validation which showed correct PV characteristics. To achieve high accuracy, the model was improved by weight function using one-year measured data. The accuracy of our developed model was verified by comparison with four commercial simulator software programs and the results from real system which were measured and recorded for 1 year. It was found that the model output was in a good agreement with the measured data. This research can be utilized in another area by adjusting the PV equation with weight function of that area. Songkiate Kittisontirak, Aekkawat Bupi, Perawut Chinnavornrungsee, Kobsak Sriprapha, Pairash Thajchayapong, and Wisut Titiroongruang Copyright © 2016 Songkiate Kittisontirak et al. All rights reserved. Optimization of Gas-Water Absorption Equilibrium of Carbon Dioxide for Algae Liquors: Selection of Alkaline Buffering Chemicals Tue, 08 Nov 2016 13:48:28 +0000 The apparent Henry’s Law constant (), which quantifies the concentration partition of a gas-liquid equilibrium of carbon dioxide (CO2), is used to optimize the absorption of carbon dioxide in algae liquors. The values of were examined under various conditions: in water at different temperatures (27 and 37°C), in alkaline buffering chemicals (sodium hydroxide (NaOH) and sodium carbonate (Na2CO3)), and in aquatic algae plants (Egeria densa and Anubias barteri nana). The optimal conditions for CO2 absorption can be obtained by controlling the aqueous pH values (around weak alkalinity with pH 9-10) using sodium carbonate as an alkaline buffering chemical at 27°C, yielding exact values of around 16.3–21.3 atm/M, which were obtained from the mean gaseous CO2 concentration of 803 ppm and the total aqueous carbonate concentration of 4.085 mg/L. The experimental results reveal that an alkaline buffering compound, sodium carbonate, can be added to water to maintain a constant aqueous alkalinity enough for the fixation of carbon dioxide by the photosynthesis of green algae in a photobioreactor. Wen-Hsi Cheng and Ming-Shean Chou Copyright © 2016 Wen-Hsi Cheng and Ming-Shean Chou. All rights reserved. Design Elements and Electrical Performance of a Bifacial BIPV Module Thu, 03 Nov 2016 09:07:09 +0000 Bifacial BIPV systems have great potential when applied to buildings given their use of a glass-to-glass structure. However, the performance of bifacial solar cells depends on a variety of design factors. Therefore, in order to apply bifacial solar cells to buildings, a bifacial PV module performance analysis should be carried out, including consideration of the various design elements and reflecting a wide range of installation conditions. This study focuses on the performance of a bifacial BIPV module applied to a building envelope. The results here show that the design elements of reflectivity and the transparent space ratio have the greatest impact on performance levels. The distance between the module and the wall had less of an impact on performance. The bifacial BIPV module produced output up to 30% greater than the output of monofacial PV modules, depending on the design elements. Bifacial BIPV modules themselves should have transparent space ratios of at least 30%. When a dark color is used on the external wall with reflectivity of 50% or less, bifacial BIPV modules with transparent space ratios of 40% and above should be used. In order to achieve higher performance through the installation of bifacial BIPV modules, design conditions which facilitate reflectivity exceeding 50% and a transparent space ratio which exceeds 30% must be met. Jun-Gu Kang, Jin-Hee Kim, and Jun-Tae Kim Copyright © 2016 Jun-Gu Kang et al. All rights reserved. Performance Analysis of Solar Assisted Fluidized Bed Dryer Integrated Biomass Furnace with and without Heat Pump for Drying of Paddy Mon, 31 Oct 2016 14:27:21 +0000 The performances of a solar assisted fluidized bed dryer integrated biomass furnace (SA-FBDIBF) and a solar assisted heat pump fluidized bed dryer integrated biomass furnace (SAHP-FBDIBF) for drying of paddy have been evaluated, and also drying kinetics of paddy were determined. The SA-FBDIBF and the SAHP-FBDIBF were used to dry paddy from 11 kg with moisture content of 32.85% db to moisture content of 16.29% db (14% wb) under an air mass flow rate of 0.1037 kg/s within 29.73 minutes and 22.95 minutes, with average temperatures and relative humidities of 80.3°C and 80.9°C and 12.28% and 8.14%, respectively. The average drying rate, specific energy consumption, and specific moisture extraction rate were 0.043 kg/minute and 0.050 kg/minute, 5.454 kWh/kg and 4.763 kWh/kg, and 0.204 kg/kWh and 0.241 kg/kWh for SA-FBDIBF and SAHP-FBDIBF, respectively. In SA-FBDIBF and SAHP-FBDIBF, the dryer thermal efficiencies were average values of 12.28% and 15.44%; in addition, the pickup efficiencies were 33.55% and 43.84% on average, whereas the average solar and biomass fractions were 10.9% and 10.6% and 36.6% and 30.4% for SA-FBDIBF and SAHP-FBDIBF, respectively. The drying of paddy occurred in the falling rate period. The experimental dimensionless moisture content data were fitted to three mathematical models. Page’s model was found best to describe the drying behaviour of paddy. M. Yahya Copyright © 2016 M. Yahya. All rights reserved. Design and Experimental Results of Battery Charging System for Microgrid System Thu, 27 Oct 2016 14:22:34 +0000 Nowadays, many countries have paid attention to renewable energy due to fossil fuel crisis and its related environmental pollution. In particular, following the government supply business for renewable energy industry, the private sectors drive the stable power supply by using renewable sources for both microgrid system and standalone application. Battery charging and discharging control system of microgrid system are critical to extend lifetime of standalone photovoltaic system. Corresponding to this demand, this paper presents the development of battery charging and discharging system based on battery modeling, SOC (state of charge) estimation, and its implementation for 5 kW. As a result, the conversion efficiency shows 96.35% with over 95% charging performance. Byunggyu Yu Copyright © 2016 Byunggyu Yu. All rights reserved. Photoelectric Properties of DSSCs Sensitized by Phloxine B and Bromophenol Blue Thu, 27 Oct 2016 12:55:08 +0000 Phloxine B and bromophenol blue as the sensitizers of dye-sensitized solar cells were investigated via UV-Vis spectra, FT-IR spectra, fluorescence spectra, and current-voltage characteristics. The frontier molecular orbital, vibration analysis, and the first hyperpolarizability were calculated with DFT/6-31G(d). The dipole moment, light harvesting efficiency (LHE), and larger absolute value of driving force of electron injection () were also discussed. The calculated results were compared with the experimental results of phloxine B and bromophenol blue. It was found that, compared with bromophenol blue, bigger dipole moment of phloxine B results in larger open circuit voltage () according to the correlation between dipole moment and . At the same time, for configuration of phloxine B, it has higher LHE and , which are helpful to enhance the abilities of absorbing sunlight and electron injection. Therefore, higher LHE and for phloxine B produced a larger value of . Penghui Ren, Yuanzuo Li, Yuehua Zhang, Hongshuai Wang, and Qungui Wang Copyright © 2016 Penghui Ren et al. All rights reserved. Fabrication and Optimization of Polymer Solar Cells Based on P3HT:PC70BM System Tue, 25 Oct 2016 06:27:06 +0000 Efficient bulk heterojunction (BHJ) polymer solar cells (PSCs) based on P3HT:PC70BM were fabricated by optimizing the processing parameters. The optimized thickness and annealing temperature have been found to be about 200 nm and 130°C. The effect of cathode interfacial layers on device performance is related to the formation of interfacial dipole. Furthermore, the effect of optimum ZnO interfacial thickness (~30 nm) on device performance is attributed to good interfacial conductivity and its optical property. The metal electrode deposited in the slow rate has a better influence on device performance. Based on these optimal conditions, the best power conversion efficiency (PCE) of 3.91% was obtained under AM 1.5G and 100 mW/cm2 illumination. This detailed investigation provides an important reference for the fabrication and optimization of polymer photovoltaic devices. Huangzhong Yu, Yanping Li, Yifan Dong, and Xinxin Huang Copyright © 2016 Huangzhong Yu et al. All rights reserved. Temperature Regulation of Photovoltaic Module Using Phase Change Material: A Numerical Analysis and Experimental Investigation Sun, 23 Oct 2016 10:22:54 +0000 This work represents an effective design of a temperature regulated PV module by integrating phase change materials for Malaysian weather condition. Through the numerical analysis and experimental investigation it has been shown that if a PCM layer of width 0.02 m of RT 35 is used as a cooling arrangement with a PV module, the surface temperature of the module is reduced by 10°C, which remains constant for a period of 4–6 hours. This reduction of temperature implies the increase in conversion efficiency of the module. Experiment as well as investigation has been carried out considering typical Malaysian weather. Obtained result has been validated by using experimental prototype and comparative analysis. Hasan Mahamudul, Md. Momtazur Rahman, H. S. C. Metselaar, Saad Mekhilef, S. A. Shezan, Rana Sohel, Sayuti Bin Abu Karim, and Wan Nur Izzati Badiuzaman Copyright © 2016 Hasan Mahamudul et al. All rights reserved. Corrigendum to “Enhanced Light Scattering by Preferred Orientation Control of Ga Doped ZnO Films Prepared through MOCVD” Tue, 11 Oct 2016 08:30:35 +0000 Long Giang Bach, Nam Giang Nguyen, Van Thi Thanh Ho, and Lu-Sheng Hong Copyright © 2016 Long Giang Bach et al. All rights reserved. Stable Inverted Low-Bandgap Polymer Solar Cells with Aqueous Solution Processed Low-Temperature ZnO Buffer Layers Sun, 09 Oct 2016 11:48:01 +0000 Efficient inverted low-bandgap polymer solar cells with an aqueous solution processed low-temperature ZnO buffer layer have been investigated. The low-bandgap material PTB-7 is employed so that more solar light can be efficiently harvested, and the aqueous solution processed ZnO electron transport buffer layer is prepared at 150°C so that it can be compatible with the roll-to-roll process. Power conversion efficiency (PCE) of the inverted device reaches 7.12%, which is near the control conventional device. More importantly, the inverted device shows a better stability, keeping more than 90% of its original PCE after being stored for 625 hours, while PCE of the conventional device is only 75% of what it was. In addition, it is found that the ZnO thin film annealed in N2 can obviously increase PCE of the inverted device further to 7.26%. Chunfu Zhang, Shangzheng Pang, Ting Heng, Hailong You, Genquan Han, Gang Lu, Fengqin He, Qubo Jiang, and Jincheng Zhang Copyright © 2016 Chunfu Zhang et al. All rights reserved.