Experimental Study on the Effect of Soiling at Various Tilt Angles of Photovoltaic Modules

Abstract

Power generation from a solar photovoltaic system is one of the glowing research fields these days, even governments are also planning toward installation and production of power generation from renewable energy sources because in the future its feasibility and crisis of conventional energy sources will increase. Further government liberalization and technical developments vitalize the use of renewable sources for electricity generation in terms of solar power. In any power production plant, improvement in the efficiency of the plant is a big and important issue. After installing the solar power plant, it is very urgent to get maximum performance from them. With all other factors, the tilt angle and azimuth angle affect the efficiency of the plant. Thus, it is very important to orient the solar modules at optimum tilt angle and azimuth angle for any given location because they are most efficient when they are perpendicular to the sun\'s rays. A comparison study was executed to achieve the power variation and dust deposition with different tilt angle in natural environment of Ajmer. Powers generated by solar cells over study period are in range of 5.10W and 3.0W. It is evident that Solar module tilted at 260 generate higher power than Solar module tilted at 00 tilted module, followed by Solar module tilted at 450.

Introduction

I. INTRODUCTION

The surface of the earth is acquiring approximately 1018 kWh/m2 of solar radiation every year [1], but is hardly use just around 1/6000 of that bulk [2]. To take the advantage of incoming solar radiation, the solar module must be installed at the optimum tilt, without disturbing our planet. The Earth moves around the sun and spins also so the sun’s positions at the different parts of the earth vary. Due to this motion solar radiation coming from the sun depends on geographic latitude, season, and time of a day [3]. Many studies have been developed to decide the optimum solar energy collector orientation. When focusing on maximum annual irradiation on an inclined surface, it is mostly proposed to orient the collecting surface toward due south with a tilt angle equal to the latitude of the geographical location. Such theoretically derived suggestions are based on direct radiation only, and practical experience recommends that when diffuse radiation is involved, different results may be obtained [4]. There are various methods are available in the literature for solar module installation for mounting.

II. LITERATURE STUDY BASED ON DIFFERENT TILT ANGLES AND ORIENTATION

The tilt angle and orientation of the PV modules are major factors that affect the efficiency of PV modules. It has been noticed that for every site on the planet with specific radiation aspect, there is an ideal tilt angle for the highest solar energy reception. By the Japan Meteorological Agency, solar radiation data has been assessed for about 60 sites to find optimal tilt angle and provide enlarged AMeDAS Weather data for 842 places in Japan. Some theoretical research has been performed regarding the optimal tilt angle using these data [5]. Data related to hourly diffused solar radiation and average incident radiation with tilt is collected at Delhi, India [6]. G. Hegde and T.V. Ramachandra collected energy requirement data for Kerala and Karnataka and then sector-wise solar energy consumption rate is explained in south India [7]. Various techniques and technology are being investigated to estimate the radiation on tilted surfaces [8-11]. R. Tang and T. Wu in his research for an optimal angle of solar surface predicated that intensity of solar radiation is higher for optimum angle in comparability to the horizontal surface [12]. Energy reception rate for different orientation is different according to the distance of the location from the equator and in southern hemisphere, the north face collector gains more power in comparison to any other orientation [13]. M. Lalwani et al. in India studied the size optimization of the SPV system under local climatic conditions. They reported that time duration of study, tilt angle, location of the site, and solar module orientation are the crucial factors for performance deviation of solar modules [14]. Research activity for estimation of tilt angle for different locations is performed by eminent researchers since optimal tilt angle is hung on the latitude of the location, climate condition, and surrounding hurdle. Generally, the latitude angle of the site is considered as the tilt angle of that particular location on the condition that the clearness index is nearly the same during the year [15].

VI. RESULTS AND DISCUSSION

Power generated from 00, 260, and 450 tilted unclean modules is plotted against the duration of the study in Fig. 1 and Power generated from 00, 260, and 450 tilted clean modules is plotted against the duration of the study in Fig. 2. Powers generated by solar cells over study period are in range of 5.10W and 3.0W. It is evident that Solar module tilted at 260 generate higher power than Solar module tilted at 00 tilted module, followed by Solar module tilted at 450 .The purpose of the study is not associated with the optimization of the tilt angles so no attempts are done to perceive the effective tilt angle β. The highest efficiencies calculated at 260 inclinations for clean module is 34.54% and for unclean module is 30.68%. The lowest efficiencies calculated at 450 inclinations for clean module is 13.76% and for unclean module is 13.55%. From Fig.9 it is clear that the deposition density on all orientations increases with prolonged exposure and 00 plates has more affinity for dust deposition than 260 and 450 degree plates. Dust deposition density changes in a range of 09 g/m2 to 18 g/m2. As the dust density increases the loss in power increases.

VII. ASSUMPTIONS AND LIMITATIONS

The test station was set up at the S.P.C. Govt. College, Ajmer. Since the outdoor soiling results were obtained only at one location, they may or may not be applicable to other climatic conditions. Energy harnessing from solar photovoltaic is influenced by different factors and all of them should be taken into the studies, for comparative analysis and interpretation of the data, to obtain valid results.

Conclusion

Ajmer, India experiences good solar irradiation with an average of about 800 W/m2 on an average from mid-Feb to mid-March. So, there is a good scope for utilization of solar energy. Power generated from all modules show gradual decline in production with reduction in solar radiation for a particular period. Because of the continuous and periodic change in the sun’s location, Fixed Tilt angle mounting of the solar modules affects the electricity production capacity of the system. From comparative study between unclean and clean PV modules tilted at various angles it is observed that 260 clean modules register considerably superior power and efficiencies.

References

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Copyright

Copyright © 2022 Dr. Tulsi Panwar. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.