Faculty Publications

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    Design and development of Tilted Single Axis and Azimuth-Altitude Dual Axis Solar Tracking systems
    (Institute of Electrical and Electronics Engineers Inc., 2017) Ray, S.; Tripathi, A.K.
    The green energy also called the renewable energy, has gained much attention nowadays. Among the renewable energy solutions, solar energy is the very vital source that can be used to generate power. Electricity from the sun can be converted through photovoltaic (PV) module. The efficiency of solar module depends on sun intensity, if the intensity is more then efficiency is more. Since the position of sun continuously changes throughout the day, the intensity of sun rays is not uniform on PV module. So, for getting more sun rays on PV module solar tracker plays a much vital role. A solar tracker is a device for operating a solar photovoltaic panel, especially in solar cell applications and requires high degree of accuracy to ensure that the concentrated sunlight is dedicated precisely on to the power device. This paper describes in detail about the design, development and fabrication of two Prototype Solar Tracking Systems mounted with a single-axis and dual-axis solar tracking controllers to generate 10.3 volts, 1.5 watts capable of charging mobile batteries. The rays from the sun should fall perpendicularly onto the solar panels to maximize the capture of the rays and this is done by pointing the solar panels towards the sun and following its path across the sky. The solar tracking systems - Tilted Single Axis Tracker (TSAT) and Azimuth-Altitude Dual Axis Tracker (AADAT) are designed, implemented and experimentally tested. The design details of TSAT and AADAT are described which detect the sunlight using Light Dependent Resistor (LDR) sensors. The control circuit for the systems is based on Atmega8 Microcontroller which is programmed to detect the sunlight through the LDR sensors and then actuate the DC geared motor using L293D motor driver to position the solar panel where it can receive the maximum sunlight. © 2016 IEEE.
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    Synthesis and characterization of Cu doped CdTe thin films for solar cell application
    (Elsevier Ltd, 2019) Ray, S.; Bangera, K.V.; Tarafder, K.
    Synthesis and characterization of thin-film based photovoltaic materials attract with great research interest for the past few years as the efficiency of the photovoltaic cell can be improved systematically with a proper functionalization of the films and making multilayers. We have synthesized Cu-doped CdTe thin films with different doping concentrations using the PVD technique. The structural, morphological, and optical properties of synthesized films were carefully investigated. Our study shows that all the prepared films are polycrystalline with a cubic structure. The morphological studies (SEM) reveal that all the films are crack and pinhole-free. The composition and stoichiometry of the film were confirmed by energy dispersive spectroscopy (EDS) study. The optical characterization of the samples is performed by using UV- VIS-NIR spectrometer. The result shows interesting optical behavior of the film suitable for solar cell applications. © 2019 Elsevier Ltd. All rights reserved.
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    Laboratory investigation of photovoltaic panel performance under the shaded condition
    (Institute of Electrical and Electronics Engineers Inc., 2020) Tripathi, A.K.; Mangalpady, M.; Ray, S.; Parida, S.
    The most encouraging use of solar energy is its conversion into electrical energy by using solar photovoltaic (PV) panel. The performance of solar-based PV panel is undoubtedly influenced by the quantity of solar radiation, which is reaching on the panel surface. The occurrence of shading over the panel surface is a vital environmental phenomenon which affects the penetration of solar radiation to reach the overall surface area of photovoltaic cells. The shading on PV panels may happen due to trees, the formation of mists, accumulation of dirt elements on the panel surface, close by long-standing structures, shadows of different panels in its region, neighbouring structures and so on. This paper is mainly focused on the study of shading impact on the panel performance. Further, this paper also observed the influence of shading on the variation of surface temperature of the PV panel. The present study shown a significant reduction of 41.40% in the maximum power output (Pmax) of the panel due to 25% shading strength of the single cell in the panel. Moreover, it was also observed that the increase in the percentage shading strength over the panel surface shifts the maximum power point (MPP), of the panel characteristics, towards the lower output voltage, which affects the effective operation of the charge controller. Further, it was seen that the shading impact degrades the performance of the panel as well as in charge of the rise of the surface temperature of the panel. In the present investigation, it was observed that the temperature of the unshaded cell rises at the rate of 1.753%, due to the shading phenomena over the panel surface. © 2020 IEEE.
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    Evaluation of solar PV panel performance under humid atmosphere
    (Elsevier Ltd, 2020) Tripathi, A.K.; Ray, S.; Mangalpady, A.; Prasad, S.
    The main aim of this paper is to study the effects of humidity on the PV panel. In this paper, the panel performance was studied in the laboratory under varied humid atmosphere. The PV performance parameters were computed by measuring its output voltage and current, amount of solar radiation incident on the panel's surface and its surface temperature by varying humidity levels artificially in the laboratory. From the studies it was observed that with rising humidity levels, solar insolation and panel power output decrease. With an increment of 50.15% in the humidity level, the panel power output reduces by 34.22%. Moreover, it was found that due to the increase in humidity from 65.40% to 98.20% the panel temperature got lowered by 11.40%. © 2020 Elsevier Ltd. All rights reserved.
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    Analysis on photovoltaic panel temperature under the influence of solar radiation and ambient temperature
    (Institute of Electrical and Electronics Engineers Inc., 2021) Tripathi, A.K.; Ray, S.; Mangalpady, M.
    The generation of electrical energy from solar energy is one of the most promising utilization of solar energy technology and it can be achieved by the application of solar photovoltaic (PV) panel. In this paper an experimental study has been conducted to examine the effect of solar radiation and ambient temperature on the surface temperature of the solar photovoltaic panel. With the help of experimental measurements, a multi-linear regression model is developed relating the three quantities. The developed model validated with the actual measured values shows good accuracy with small values of root mean square error. During the study, the recordedvalue of maximum panel temperature was 78.50°C for the atmospheric condition which having solar radiation of 1140 W/m2 and ambient temperature of 36°C. The developed relation and subsequent outcomes of the study will help the PV panel designers and manufacturers incomprehending the effects of atmospheric parameters on the temperature of the photovoltaic panel. © 2021 IEEE
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    Design and Development of an IoT-Based Gas Monitoring System for Underground Coal Mines
    (Springer Science and Business Media Deutschland GmbH, 2023) Tripathi, A.K.; Mangalpady, M.; Rao, N.R.N.V.; Ray, S.
    Safety in underground coal mines is a major challenge whenever the mine comprises of toxic gases. The risk of the presence of gas influences the overall productivity of the mines, which is a subject of concern to the mining industry. Therefore, there is a need for real-time monitoring of underground mine environment, so that the miners can be safeguarded in case of presence of toxic gases. In this paper, an attempt was made to evolve and validate an Internet of Things (IoT)-based gas monitoring system for monitoring underground coal mines environment, which includes multiple sensors for real-time measurement of different gases. The developed IoT-based gas monitoring system was tested and validated in the laboratory, under the controlled environmental conditions, for the measurement of carbon dioxide (CO2), carbon monoxide (CO) and methane (CH4) gases. Further, the test results were compared with the readings obtained by the digital multi-gas detector, which confirmed that the developed real-time gas monitoring system yields a good result. © 2023, The Author(s), under exclusive license to Springer Nature Singapore Pte Ltd.
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    Development and Evaluation of Dust Cleaning System for a Solar PV Panel
    (University of Kuwait, 2022) Tripathi, A.K.; Mangalpady, M.; Ray, S.; Rao, N.R.N.V.; Vamshi Krishna, S.; Durgesh Nandan, D.
    The most promising application of solar energy is the conversion of solar energy into electrical energy by using solar photovoltaic (PV) panel. The performance of solar based PV panel is definitely influenced by the amount of solar radiation, which are reaching on the panel surface. Since the solar PV panels are operating in open atmosphere dust particles get deposited on their surfaces and most of the times they have to work in this condition. These deposited dust particles create a layer of dust particles over the panel surface which prevents the 100% penetration of solar radiation into the panel surface. Therefore, proper cleaning of the panel surface becomes very necessary. In order to improve the performance of the PV panel an automatic microcontroller driven dust cleaning technique is developed which is capable of removing the accumulated dust particles from the PV panel surface. Moreover, an experimental study has been performed to analyse the efficiency of this developed techn ique. The developed cleaning system showed an improvement of 27.98% in the output power of PV panel when compared to the dusty panel. © 2022 University of Kuwait. All rights reserved.
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    Photo- and Electrocatalytic Reduction of CO2 over Metal-Organic Frameworks and Their Derived Oxides: A Correlation of the Reaction Mechanism with the Electronic Structure
    (American Chemical Society, 2022) Payra, S.; Ray, S.; Sharma, R.; Tarafder, K.; Mohanty, P.; Roy, S.
    A Ce/Ti-based bimetallic 2-aminoterephthalate metal-organic framework (MOF) was synthesized and evaluated for photocatalytic reduction of CO2 in comparison with an isoreticular pristine monometallic Ce-terephthalate MOF. Owing to highly selective CO2 adsorption capability, optimized band gaps, higher flux of photogenerated electron-hole pairs, and a lower rate of recombination, this material exhibited better photocatalytic reduction of CO2 and lower hydrogen evolution compared to Ce-terephthalate. Thorough probing of the surface and electronic structure inferred that the reducibility of Ce4+ to Ce3+ was due to the introduction of an amine functional group into the linker, and low-lying Ti(3d) orbitals in Ce/Ti-2-aminoterephthalate facilitated the photoreduction reaction. Both the MOFs were calcined to their respective oxides of Ce1-xTixO2 and CeO2, and the electrocatalytic reduction of CO2 was performed over the oxidic materials. In contrast to the photocatalytic reaction mechanism, the lattice substitution of Ti in the CeO2 fluorite cubic structure showed a better hydrogen evolution reaction and consequently, poorer electroreduction of CO2 compared to pristine CeO2. Density functional theory calculations of the competitive hydrogen evolution reaction on the MOF and the oxide surfaces corroborated the experimental findings. © 2022 American Chemical Society.
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    ZnSxSe1−x thin films: A study into its tunable energy band gap property using an experimental and theoretical approach
    (Elsevier Ltd, 2022) Ray, S.; Barman, B.; Darshan, C.; Tarafder, K.; Bangera, K.V.
    In recent times, ZnS and ZnSe thin films are drawing tremendous attention towards opto-electrical devices due to their optimal wide band gap energy. By alloying ZnS and ZnSe films to obtain ZnSxSe1−x thin films, the band gap of the ZnSxSe1−x film can be tuned to a value according to the device requirements. Herein, ZnSxSe1−x thin films were deposited on pre-cleaned glass substrates using a thermal evaporation system and the various properties of the obtained thin films were analyzed by altering the percentage of sulfur concentration in the films. The XRD analysis illustrated that the prepared films are polycrystalline in nature and oriented along cubic (1 1 1) plane. The deviation of (1 1 1) preferential peak position with composition ‘x’ along the absence of any secondary peaks confirms the formation of ternary ZnSxSe1−x thin films. DFT analysis verifies the formation of pristine ZnSxSe1−x alloy system. FESEM micrographs displayed that the ZnSxSe1−x thin films do not have any cracks or pinholes. EDAX analysis of the films revealed the existence of Zn, Se and S in an appropriate quantity. Optical analysis revealed the effective band gap tailoring of ZnSxSe1−x thin films. The band gap of the ZnSxSe1−x thin films increases from 2.59 eV to 3.38 eV as the composition ‘x’ varied from 0 to 1 and band composition was determined using the DOS plot obtained using VASP. © 2022 International Solar Energy Society
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    Investigation of CdSe and ZnSe as Potential Back Surface Field Layers for CdTe-Based Solar Cells: A Study from First Principles Calculations
    (John Wiley and Sons Inc, 2023) Ray, S.; Tarafder, K.
    A class of II–VI semiconductors, especially CdTe, is a highly photo-reactive compound that would be suitable for photovoltaic applications. However, being a highly resistive material, CdTe produces considerable contact resistance and drastically reduces the efficiency of photovoltaic devices. Introducing a back surface field layer at the contact region may significantly improve the device's performance. This work investigates the suitability of using ZnSe and CdSe layer as a back-surface-field layer in CdTe-based solar cells through accurate electronic structure calculations using the hybrid-density functional theory method. The calculations show that both ZnSe/CdTe and CdSe/CdTe behave as type-II heterojunctions with band gaps of 2.0 and 1.1 eV, respectively. The Mulliken electronegativity method is used to determine the correct band edge positions concerning the vacuum level for all the pristine semiconductors and their interfaces. Calculation shows that a significant charge redistribution in the interface leads to the formation of an effective local field near the contact region for both ZnSe/CdTe and CdSe/CdTe heterostructures. This local field may help to separate the photogenerated electron–hole pairs in the active layer by pushing the opposite charges into the two different sections of the heterojunction. Additionally, the heterojunctions also exhibit better light-absorption characteristics in the visible light range. © 2023 The Authors. Advanced Theory and Simulations published by Wiley-VCH GmbH.