Faculty Publications
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Publications by NITK Faculty
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Item 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.Item 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 IEEEItem Numerical Investigation on the Effect of Various Geometries in a Solar Box-Type Cooker: A Comparative Study(Springer Science and Business Media Deutschland GmbH, 2021) Anilkumar, B.C.; Maniyeri, R.; Anish, S.The solar energy as a renewable energy has been the primary interest of many researchers for the last four to five decades due to its wide applications such as domestic cooking systems. The present study aims to investigate the effect of various box geometries such as rectangular, trapezoidal, cylindrical and frustum of a cone on the performance of solar cookers. In this study, various heat losses (convective and radiative) from the cooker cavities are analysed by simulating the condition using commercial software ANSYS16. The results of numerical analysis of rectangular cavity box-type cooker are validated by comparing with experimental results. The results show that trapezoidal cavity box-type solar cooker has higher absorber plate temperature and minimum heat losses than all other geometries operating under the same conditions. © 2021, The Author(s), under exclusive license to Springer Nature Singapore Pte Ltd.Item Analysis of IRS-P4 OCM data for estimating the suspended sediment concentrations along the Mangalore Coast, India(2010) Warakish, G.S.D.; Natesan, U.; Nayak, S.R.; Chauhan, P.; Nagur, C.R.C.Information on Suspended Sediment Concentration (SSC) in coastal waters is necessary for the understanding and management of the coastal environment. In the present study, estimation of SSC has been carried out along the Mangalore Coast, West coast of India, using both in-situ and Indian Remote sensing Satellite (IRS) - P4 Ocean Color Monitor (OCM) data. The OCM Data Analysis Software (OCMDAS) developed by Space Applications Centre (SAC), Ahmedabad, India, which is based Tassan's algorithm was used to estimate the SSC and validated through sea-truth data collected along the Mangalore Coast. Eighty six surface water samples were collected during the post-monsoon (21.11.1999) and pre-monsoon (07.05.2000) period, near synchronized with IRS-P4-satellite overpass, and SSC was measured using 0.47?m Whatman filter papers with the help of Millipore filter assembly. Out of ninety water samples, eighty two were used to generate the SSC map of the study area and eight samples at few important locations (rivermouth with/without breakwater, man-made coastal structures, and open beaches) were selected to validate the algorithm. Measured SSC varied between 26mg/L and 48mg/L in pre-monsoon and between 16mg/L and 40mg/L during post-monsoon period. The estimated SSC varied between 11mg/L and 47mg/L in pre-monsoon and between 14mg/L and 33mg/L during post-monsoon period. The co-efficient of determination for the relationship developed between measured and estimated SSC is about 0.90 and root mean square error is <14 mg/L. © 2010 by IJI (CESER Publications).Item Vegetation dynamics in a tropical river basin inferred from MODIS satellite data(2013) Laxmi, K.; Nandagiri, L.The objective of this study was to analyze temporal and spatial dynamics of vegetation and land use/land cover (LU/LC) characteristics in a humid tropical river basin originating in the forested Western Ghats mountain ranges using the Moderate Resolution Imaging Spectroradiometer (MODIS) satellite data. Both intra-annual and inter-annual variations in the parameters related to vegetation were analyzed in the Netravathi river basin (3314 km2) which is located in Karnataka State, India. MODIS data products on Land Surface Temperature and Reflectance were used as input to map the pixel-wise variations in albedo, Normalized Difference Vegetation Index (NDVI), Fraction of Vegetation (Fr) and Land Surface Temperature (LST) for two dates each (summer and winter) during the years 2002 and 2006. The fact that 2002 experienced a relatively wet summer followed by a relatively dry winter and 2006 experienced opposite conditions, proved useful in interpreting variations as influenced by wetness conditions. Overall results indicated significant variability in the parameters for major LU/LC classes of evergreen /semievergreen forest, scrub forest and agriculture. While albedo values appeared quite sensitive to wetness conditions, NDVI (and Fr) exhibited significant seasonal changes for some LU/LC classes but remained largely unaffected by wetness conditions. LST values corrected for elevation effects (LST*) were influenced by both LU/LC and wetness conditions. Differences in LST* values were as high as 70K between summer and winter of 2006 for some LU/LC classes. Lowest temperatures were recorded for the evergreen/ semievergreen forest class. Similar inferences could be drawn when variations in parameters were analyzed for 20 selected pixels located at different elevations and possessing each of the eight LU/LC classes. The methodology proposed in this research may prove to be useful in regional scale monitoring and mapping of tropical forests and other LU/LC categories in a convenient and cost-effective manner. MODIS satellite data products used in this study provides information on surface characteristics at a reasonable resolution. This permits identification of not only differences in LU/LC classes but also on changes in surface characteristics as influenced by season and wetness conditions. © 2013 CAFET-INNOVA TECHNICAL SOCIETY.Item Highly transparent and conducting ITO/Ag/ITO multilayer thin films on FEP substrates for flexible electronics applications(Elsevier B.V., 2017) Sibin, K.P.; Srinivas, G.; Shashikala, H.D.; Dey, A.; Sridhara, N.; Sharma, A.K.; Barshilia, H.C.Transparent and conducting ITO/Ag/ITO (IAI) multilayer coatings were deposited on glass and flexible fluorinated ethylene propylene (FEP) substrates by reactive sputtering using metallic In:Sn (90%:10%) and Ag targets at room temperature. Middle Ag layer thickness was optimized to obtain maximum figure of merit (?) and the optimum Ag layer thickness was found to be ~13 nm. The optimized IAI multilayer on glass substrate showed transmittance of ~88.6% and sheet resistance of ~7.1 ?/sq. The transmittance increased to ~91.4% for the IAI multilayer deposited on one side etched glass. The optimized IAI multilayer coating was also deposited on flexible FEP substrates. The electrical, optical, structural and morphological properties of IAI deposited on glass and FEP substrates were compared. IAI deposited on FEP substrate showed transmittance of ~90.2% at ? = 550 nm, sheet resistance of ~6.9 ?/sq. and figure of merit of ~52 × 10?3 ??1. Bending test of IAI deposited FEP proved the high flexibility of IAI multilayer for the flexible transparent electrode applications. Solar selectivity study of IAI on FEP substrate showed it can effectively reflect the higher wavelength region of solar spectrum and can be used as a flexible solar spectrum segregator. Optical haze measurements of IAI coated glass and FEP show that high haze value can be achieved by increasing the roughness on non-coated side of the FEP substrate. © 2017Item Thermal and cost analysis of float and various tinted double window glass configurations on heat gain into buildings of hot & dry climatic zone in India(International Information and Engineering Technology Association info@iieta.org, 2018) Gorantla, G.; Saboor, S.; Setty, A.B.T.P.R.Glass window enclosures for buildings consume a lot of energy for affording thermal and visual comfort. Reducing solar radiation in summer and increase in winter through different double window glasses for making energy efficient building design is the theme of this paper. Therefore this work measures the spectral characteristics of four glasses namely grey, green, bronze and clear glasses in entire solar spectrum region from 300nm to 2500nm at normal angle of incidence by using Shimadzu UV 3600 spectrophotometer based on ASTM standards. To find the solar optical properties a MATLAB code was used which is based on British standards. To find the solar radiation transmission from different double window glass configurations and cost analysis from eight coordinal directions at peak summer and winter day were selected as per Indian standards with a MATLAB code to hot and dry climatic zone of Jodhpur (26.300N, 73.020E). From these results it is shows that in south direction all double glass windows are gaining less heat in summer and more heat in winter season when compared to other orientations. It is found that south orientation C1(Greyglasswindow-Airgap10mm-Greenglasswindow) and C12(Clearglasswindow-Airgap10mm-Bronzeglasswindow) configuration windows are gaining minimum and maximum heat in summer and winter respectively when compared to other configuration windows. Among all windows C1 configuration window is saving more cost annually. © 2018 International Information and Engineering Technology Association. All rights reserved.Item Thermal and energy saving analysis by using tinted double window glass combinations for heat gain in buildings(Regional Energy Resources Information Center (RERIC) rericjournal@ait.ac.th, 2018) Gorantla, K.; Saboor, S.; Babu, A.; Ranga, P.; Setty, T.Buildings consume large amount of energy to accommodate thermal and visual comforts, in which glass windows play an important role as we used as building envelope. Universally clear glass is used as chief building envelope for buildings. As clear glass is having more transmission property it permits more radiation and day light into the buildings which creates uneasy feeling to the occupants. This paper presents the experimental measurement of spectral characteristics of three tinted glasses which include transmission and reflection in entire solar spectrum wavelength region from 300nm to 2500nm as per ASTM standards by using UV 3600 Shimadzu spectrophotometer. These measured spectral characteristics were used to compute solar optical properties as per British standard by using MATLAB code. To find the total solar radiation through double tinted window glass combinations GC1 to GC6 place as building envelopes of New Delhi climatic zone by using MATLAB code and to find the monthly solar radiation passing into the building which is helpful to calculate the cost energy saving annually for cooling and heating loads. From the results GC6 combination windows are saving cost i.e. 61.16 (US Dollars/year) in south, 60.54 (US Dollars/year) in south east and 59.23 (US Dollars/year) in south west orientations annually than other combination windows.Item A Hybrid Global Maximum Power Point Tracking Technique with Fast Convergence Speed for Partial-Shaded PV Systems(Institute of Electrical and Electronics Engineers Inc., 2018) Goud, J.S.; Kalpana, R.; Singh, B.Photovoltaic (PV) systems exhibit multiple local and one global maximum power points (MPPs) in their P -V and I-V curves during partial shading conditions (PSC). Thus, to improve the efficiency of the system, a global maximum power point tracking (GMPPT) algorithm is necessary. This paper presents a hybrid GMPPT algorithm for constant voltage load applications using a single current sensor. The proposed method combines single current sensor hill climbing (SSHC) and artificial bee colony (ABC) algorithms to track the GMPP. The SSHC algorithm detects the event of PSC and tracks the MPP during uniform insolation conditions. The output current of the power electronic interface is measured effectively at selective duty cycles to identify the type of P-V curve pattern and, thus, initiate either SSHC or ABC. The search space for the ABC algorithm is reduced in the proposed technique to improve the convergence speed. The proposed GMPPT technique is simulated in MATLAB and validated through experimental prototypes for various PSCs. The proposed algorithm tracks the GMPP with excellent efficiency and fast speed. © 1972-2012 IEEE.Item Output power enhancement of solar PV panel using solar tracking system(Bentham Science Publishers B.V. P.O. Box 294 Bussum 1400 AG, 2019) Tripathi, A.K.; Mangalpady, M.; Murthy, C.S.N.Solar Photovoltaic (PV) energy conversion has gained much attention nowadays. The output power of PV panel depends on the condition under which the panel is working, such as solar radiation, ambient temperature, dust, wind speed and humidity. The amount of falling sunlight on the panel surface (i.e., solar radiation) directly affects its output power. In order to maximize the amount of falling sunlight on the panel surface, a solar tracking PV panel system is introduced. This paper describes the design, development and fabrication of the solar PV panel tracking system. The designed solar tracking system is able to track the position of the sun throughout the day, which allows more sunlight falling on the panel surface. The experimental results show that there was an enhancement of up to a 64.72% in the output power of the PV panel with reference to the fixed orientation PV panel. Further, this study also demonstrates that the full load torque of the tracking system would be much higher than the obtained torque, which is required to track the position of the sun. This propounds, that the proposed tracking system can also be used for a higher capacity PV power generation system. © 2019 Bentham Science Publishers.