Subhasis Neogi

A simple and efficient sun tracking mechanism using programmable logic controller

To increase the unit area illumination of solar ray on PV panel, it is required to track the sun throughout the day. So to reach the goal various type of sun tracking mechanism is already developed but in this paper we designed two different types of sun tracking mechanism: single axis and dual axis tracking using programmable logic controller (PLC) as it has numbers of unique advantages like—it is faster, reliable, requires less maintenance and reprogrammable. A comparative study between those two systems is also presented in this paper. The whole system has been designed and tested using GE, FANUC PLC.

Microstructural and optical characterizations of sol–gel based nanoclustered indium (III) doped cadmium(II) oxide films on glass

Thin films of indium doped cadmium oxide have been developed on glass by sol–gel dipping process. Four different In: Cd atomic ratios, 01: 99, 04: 96, 07: 93, 10: 90 were selected initially for the precursors to develop nanostructured films. Microstructure evaluation by SEM, FESEM and TEM experiments has led to the detailed study of the films of In: Cd = 10: 90 prepared in different atmospheres. XRD depicted cubic In2O3, CdO along with spinel CdIn2O4 and wurtzite CdO preferably in nitrogen atmosphere. Band gap evaluation highlighted the excitonic transitions for the occurrence of quantum confinement in the nanoclusters. Photoluminescence (PL) of the films exhibited the presence of free exciton, bound exciton and interaction of excitons with LO phonons of wurtzite CdO evidenced from the satellite peaks of PL emission bands.

Optimum Tilt Angles for Manual Tracking of Photovoltaic Modules

ABSTRACTThis article reports the investigation for the average optimal tilt angle of solar panels on a monthly basis (single axis tracking) for a wide range of latitudes in the northern hemisphere to collect maximum total solar irradiation. Based on experimentally validated modeling, a new set of empirical relations has been proposed to compute the optimum tilt angle on a monthly basis for the entire year. The accuracy of equations set is evaluated by standard statistical measures. The proposed set of empirical equations is compared with an existing set of empirical equations on various cities within the latitude and has yielded significantly better results. Solar Advisory Model (SAM) has been used to compare—with respect to a fixed Solar Photo Voltaic (SPV) panel—the electricity predicted by (1) a new set of manual solar tracking equations, (2) an established set of solar tracking equations, and (3) data from an automated single axis tracking system by a Programmable Logic Controller or PLC. It is found ...

Study on the Effect of Tilt on the Variation of Aperture Area Shading in a Linear Fresnel Reflector Field for Two Different Configurations

Linear Fresnel reflector (LFR) consists of parallel rows of reflectors that direct the incident solar radiation on to a common focus. A linear receiver placed at the common focus absorbs the reflected solar radiation. Due to continuous change in Sun’s position in sky, continuous tracking of reflectors is required that leads to variable shading losses. Portion of reflector area gets shaded due to adjacent reflector row, and the amount of shading varies throughout the day and year. In this work, analytical expression has been used to determine the shaded aperture areas for two different system configurations. Monthly and yearly average values of shading loss factor at different system tilt angles have been plotted and compared.

Study on the end effect loss of a Linear Fresnel Collector system

Linear Fresnel Collector (LFC) consists of parallel reflector rows on a horizontal plane that reflects the incident solar radiation on to a common focal plane. Receiver positioned at the common focal plane absorbs the reflected solar radiation. As the Suns position in sky changes throughout the day and year, portion of reflected rays that reach the absorber varies. Fraction of absorber area remains unused due to no radiation falling on it. This phenomenon is of utmost importance in small scale LFCs, where this forms a major proportion of optical losses. Thus, the variation of end-effect loss for different tilt angles and its dependency on time of day and month of year has been studied, plotted and compared.

Reassessment of the Indian renewable energy policy through technology implementation

Govt. of India scaled up of budget during 12th five year plan for Rooftop solar project to achieve the target of 40 GWp as committed before UNFCC (United Nations Framework Convention on Climate Change). In this connection through a case study it is shown that there is a chance to reduce the target and also the space of solar project installation if a manual solar tracking based on optimum tilt angle as proposed in the study can be included in the policy for future small solar project initiatives. An equation set of monthly solar optimum tilt angle has been proposed based on an anisotropic validated model developed by FORTRAN 77 Compiler. The equation set is applicable for a wide latitude range of 13° to 39° of northern hemisphere i.e. it includes all over India. If the proposed optimum tilt based manual tracking has been adopted in Govt. policy of solar project then the target to UNFCC will be reduced to 36.5 kWp i.e. a decrease of 8.75% and the required area for solar installation will also be decreased of 8.84%.

Iterative Model for the Performance Evaluation of a Horizontal Axis Wind Turbine

This paper is based on the studies made on a numerical model for calculating the turbine characteristics at low tip speed ratio for a Horizontal Axis Wind Turbine. The turbine characteristics are analysed for different configurations over the total operating range i.e. from tip speed ratio of zero to a maximum value where CP becomes zero. The simulation model provides acceptable results, however for the blade position near the hub, a non-convergent situation is observed i.e. the flow parameters converge to values outside those associated with turbine operation. This indicates the possibility of a multisolution.