Faculty Publications
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Item Novel hybrid photocatalytic reactor-UF nanocomposite membrane system for bilge water degradation and separation(Royal Society of Chemistry, 2015) Moslehyani, A.; A.F., A.F.; Othman, M.H.D.; Isloor, A.M.This study focuses on the design and performance of a hybrid system consisting of a photocatalytic reactor and ultrafiltration permeation cell. Initially, an ultraviolet (UV) lamp was installed in the photocatalytic reactor to decompose the bilge organic pollutants in the presence of 200 ppm titanium-dioxide (TiO2). Individual hydrocarbon compounds of bilge water samples were identified by gas chromatography-mass spectrometry (GC-MS) analysis. Two types of membrane, which are a pure polyvinylidene fluoride (PVDF) membrane and PVDF/modified halloysite nanotube clay (M-HNTs) nanocomposite membrane were fabricated aiming to enhance the rejection, flux and fouling resistance for full filtration of pollutants from the photocatalytic reactor. The membranes were characterized by Fourier transform infrared (FTIR), field emission scanning electron microscopy (FESEM) and atomic force microscopy (AFM). Furthermore, GC-MS analysis showed that, over 90% bilge decomposition occurred by a photocatalytic reaction. The TiO2 cross-over during permeation was detected by using an atomic absorption spectrophotometer (AAS), which proved that, TiO2 rejection was more than 99% for the nanocomposite membrane. A UV- vis spectrophotometer confirmed over 99% rejection of decomposed bilge hydrocarbons via the nanocomposite membrane with 1.0 wt% of M-HNTs incorporated in the PVDF matrix. This journal is © The Royal Society of Chemistry 2015.Item An integrated Control Approach and Power Management of Stand-alone Hybrid Wind/PV/Battery Power Generation System with Maximum Power Extraction Capability(Taylor and Francis Inc. 325 Chestnut St, Suite 800 Philadelphia PA 19106, 2015) Sabhahit, N.S.; Gaonkar, D.N.The production of electricity from renewable energy sources like wind and photovoltaic energy has increased in recent years, due to environmental problems and the shortage of traditional energy sources. In this article we present a detailed mathematical model and a control scheme for hybrid wind and PV based DG system with battery and maximum power extraction capability for isolated mode of operation. The wind power generation system uses wind turbine (WT), a permanent magnet synchronous generator (PMSG), a three-phase diode rectifier bridge, DC/DC boost converter with maximum power point tracking (MPPT) controller. The PV generation system uses PV array, a boost converter with maximum power point tracking controller. Both sources and battery are connected to common dc bus with a dc link capacitor and supply power to load through PWM voltage source inverter. The overall control system consists of MPPT controller for both Wind and PV power system, a bi-directional DC-DC converter controller for battery energy storage management and load side inverter controller for voltage and frequency regulation. Control strategies for individual system components of the proposed system are designed with a view to achieve an acceptable level of voltage and frequency regulation while extracting the maximum power from wind and PV system. The performance of the developed hybrid system is investigated in terms of voltage and frequency regulation capability under changing wind, solar irradiation and variable load conditions.Item Power control of PV/fuel cell/supercapacitor hybrid system for stand-alone applications(International Journal of Renewable Energy Research, 2016) Sabhahit, N.S.; Gaonkar, D.N.; Nempu, P.B.This paper presents modeling and control of photovoltaic/fuel cell/supercapacitor hybrid power system for stand-alone applications. The hybrid power system uses solar photovoltaic array and fuel cell as the main sources. These sources share their power effectively to meet the load demand. The supercapacitor bank is used to supply or absorb the power during load transients. The main control system comprises of controller for maximum power tracking from photovoltaic system, a DC-DC boost converter with controller for fuel cell system for power management and inverter controller to regulate voltage and frequency. The stand-alone hybrid system aims to provide quality power supply to the consumers with a constant voltage and frequency along with proper power management using simple control techniques. The modeling and control strategies of the hybrid system are realized in MATLAB/Simulink.Item Modelling and analysis of a standalone PV/micro turbine/ ultra capacitor hybrid system(International Journal of Renewable Energy Research, 2016) Shalavadi, B.; Chowdary, V.; Yaragatti, R.Y.Nowadays the distributed generation is being vastly implemented due to its various advantages. Generally a non renewable source is connected in parallel to a renewable source. Normally Photo Voltaic (PV) generation gives the power necessary by the load. The output of the PV is varying due to various reasons like temperature, irradiation, etc. Distributed generation using micro turbine is a realistic solution because of its friendliness with environment, small in size and high efficiency of energy. If the load is more than PV power capability, micro turbine supplies the remaining power. Due to the varying load conditions, the micro turbine practically compensates all the PV fluctuations of power. Even so, to reduce the fast fluctuations of power, one need to use an energy storage system like battery, ultra capacitor and flywheel etc. Ultra capacitor has been chosen, because of the its high power density and very fast energy storing capability. This paper documents the simulation and analysis of a standalone Photovoltaic / Micro turbine hybrid system and Photovoltaic / Micro turbine / Ultra capacitor hybrid system using MATLAB/SIMULINK simulation software. The system is implemented based on the concept of a parallel hybrid configuration. The simulation results validate the proposal.Item Performance analysis of a variable-speed wind and fuel cell-based hybrid distributed generation system in grid-connected mode of operation(Taylor and Francis Inc. 325 Chestnut St, Suite 800 Philadelphia PA 19106, 2016) Ayyappa, S.K.; Gaonkar, D.N.This article presents the performance study of a variable-speed wind and solid oxide fuel cell-based hybrid distributed generation system, along with the energy storage devices in the grid connected mode of operation. The developed model has a salient feature of utilizing fluctuating output power of wind systems to produce hydrogen and also to charge the ultra capacitor. The presented model in the article also uses the stored energy in the ultra capacitor to compensate for the slow response time of the fuel cell. The distributed generation systems and energy storage devices considered in this study are integrated at common distributed generation links to form the hybrid system. The hybrid system is interfaced to the grid through the three-phase voltage source inverter in this article. The detailed modeling of the individual components of the hybrid distributed generation system, along with the necessary power electronic converter control schemes, are presented. The simulation results reported in this article show the effective performance of the hybrid model to produce reliable, low-cost electricity and hydrogen from the variable wind generation system. © 2016 Taylor & Francis Group, LLC.Item Photoreactor-ultrafiltration hybrid system for oily bilge water photooxidation and separation from oil tanker(Elsevier, 2016) Moslehyani, A.; Mobaraki, M.; Isloor, A.M.; A.F., A.F.; Othman, M.H.D.A novel design of hybrid system consisting of photoreactor (PR) combined with ultrafiltration (UF) membrane was investigated for oily bilge water degradation and separation from oil tanker. Initially, the bilge organic compounds were photooxidized using ultraviolet type A (UVA) light irradiation on 100, 200 and 300 ppm of TiO2. Further TiO2 and oxidized oily bilge water was filtered using hollow fiber membrane separator, which was prepared by polyvinylidene fluoride (PVDF) and halloysite nanotubes. The hollow fiber membranes were characterized by ATR-IR spectrum, thermal gravimetric analysis (TGA), X-ray diffraction (XRD), field emission scanning electron microscopy (FESEM) and X-ray photoelectron spectroscope (XPS). Individual hydrocarbon of oily bilge water was identified by using gas chromatography-mass spectrometry (GC-MS) analysis. According to the GC-MS analysis, over 90% decomposition of oil in bilge water has occurred by 200 and 300 ppm of TiO2 suspension. On the other hand, pH meter showed that, decomposed oily bilge water was more acidic, which increased to pH 7 after UF system process. Moreover, over 99% of degraded oil in bilge water was filtered by this promising hybrid system. © 2016 Elsevier B.V. All rights reserved.Item A new control method to mitigate power fluctuations for grid integrated PV/wind hybrid power system using ultracapacitors(Walter de Gruyter GmbH info@degruyter.com, 2016) Sabhahit, N.S.; Gaonkar, D.N.The output power obtained from solar-wind hybrid system fluctuates with changes in weather conditions. These power fluctuations cause adverse effects on the voltage, frequency and transient stability of the utility grid. In this paper, a control method is presented for power smoothing of grid integrated PV/wind hybrid system using ultracapacitors in a DC coupled structure. The power fluctuations of hybrid system are mitigated and smoothed power is supplied to the utility grid. In this work both photovoltaic (PV) panels and the wind generator are controlled to operate at their maximum power point. The grid side inverter control strategy presented in this paper maintains DC link voltage constant while injecting power to the grid at unity power factor considering different operating conditions. Actual solar irradiation and wind speed data are used in this study to evaluate the performance of the developed system using MATLAB/Simulink software. The simulation results show that output power fluctuations of solar-wind hybrid system can be significantly mitigated using the ultracapacitor based storage system. © by De Gruyter 2016.Item Design and development of ITO/Ag/ITO spectral beam splitter coating for photovoltaic-thermoelectric hybrid systems(Elsevier Ltd, 2017) Sibin, K.P.; Selvakumar, N.; Kumar, A.; Dey, A.; Sridhara, N.; Shashikala, H.D.; Sharma, A.K.; Barshilia, H.C.ITO/Ag/ITO (IAI) multilayer coatings were designed for spectral beam splitter applications and these coatings were deposited on glass substrates by magnetron sputtering method. The thicknesses of the component layers, namely, Ag and ITO were varied to achieve high visible transmittance, high NIR-IR reflectance and optimum cut-off wavelength. The optimized ITO/Ag/ITO exhibits high visible transmittance (?88%) and high NIR-IR reflectance (>90%) with an optimum cut-off wavelength (?900 nm). A novel chemical etching method was used to improve the transmittance of the plain glass substrate. The optimized IAI multilayer coating deposited on single side etched glass substrate resulted in increase in transmittance (?91%), which is due to the nano-porous morphology of the etched glass substrate. The angular and polarization dependence studies of IAI multilayer coatings were also studied in detail. © 2016 Elsevier LtdItem Integrated power flowand voltage regulation of stand-alone PV-fuel cell system with supercapacitors(Acta Press journals@actapress.com, 2017) Sabhahit, J.N.; Gaonkar, D.N.; Nempu, P.B.The output of the solar cell is fluctuating due to intermittency of solar irradiation. Hybridizing the solar photovoltaic (PV) system with other sources and appropriate storage devices is essential to generate electricity continuously. This paper presents the control strategies for a PV-fuel cell hybrid power system with supercapacitor bank for isolated load applications. Supercapacitor bank is controlled using a bidirectional DC/DC converter so as to regulate voltage at a DC link and to keep the system stable under transient load variations. The H-bridge inverter is controlled to regulate voltage and frequency across the load. The PV system is controlled to extract maximum power using the maximum power point tracking algorithm. This paper aims to provide a single-phase supply with constant voltage and frequency to the consumers with proper power sharing among different sources. The hybrid system is realized in Matlab/Simulink environment.Item Design of backstepping controller for PV-wind hybrid system with grid-interfacing and shunt active filtering functionality(Inderscience Enterprises Ltd., 2018) Jayasankar, V.N.; Vinatha Urundady, U.This paper presents the design of a double loop controller for the grid interconnection of PV-wind hybrid system with shunt active filtering and neutral current compensation capabilities. Using Lypunov stability theory-based procedure, a backstepping controller is designed for the outer loop DC link voltage control. The adaptive nature of back stepping controller results in better dynamic performance compared to conventional controllers. Inner loop consists of instantaneous power theory-based controller for harmonic current compensation. Instantaneous power theory is modified by employing positive sinusoidal sequence regulator and self-tuning filter to improve the system performance in unbalanced and distorted grid voltage conditions. A dynamic model of the system is considered for the design. Numerical simulations are done in MATLAB/Simulink platform for different system conditions to verify the effectiveness of controller in grid interfacing of renewable sources, and the shunt active filtering. © © 2018 Inderscience Enterprises Ltd.