Solar Irradiance and Solar Cell Efficiency

Photovoltaic system utilizes the naturally available solar energy without creating any negative effect on the environment. Solar energy is relatively available in different regions of the world and this makes it a very vital source of renewable energy. The exposure of the earth’s surface to the sun rays varies with the earth’s revolution and rotation and to get maximum energy from the sun, the incident solar beam must always be at 90o to the solar cells at all times. To achieve this, a solar tracker is required which senses the direction of the solar rays and adjusts the position of the solar panel accordingly. This paper is based on the design and implementation of an effective and low cost sensor-enabled solar tracking device which uses photo-sensors to detect sunlight and the measured intensity is read as input by a microcontroller which commands an actuator to change the position of the solar panel for maximum energy reception. The test results after design implementation shows ...

The present study is divided into two parts. The first part deals with the comparison of various hourly slope irradiation models, found in the literature, and the selection of the most accurate for the region of Athens. In the second part the prediction of global solar irradiance on inclined surfaces is performed, based on neural network techniques. The models tested are classified as isotropic (Liu and Jordan, Koronakis, Jimenez and Castro, Badescu, Tian) and anisotropic (Bugler, Temps and Coulson, Klucher, Ma and Iqbal, Reindl) based on the treatment of diffuse irradiance. For the aforementioned models, a qualitative comparison, based on diagrams, was carried out, and several statistical indices were calculated (coefficient of determination R2, mean bias error MBE, relative mean bias error MBE/A(%), root mean square error RMSE, relative root mean square error RMSE/A(%),statistical index t-stat), in order to select the optimal. The isotropic models of ‘‘Tian’’ and ‘‘Badescu’’ show the best accordance to the recorded values. The anisotropic model of ‘‘Ma&Iqbal’’ and the pseudo-isotropic model of ‘‘Jimenez&Castro’’, show poor performance compared to other models. Finally, a neural network model is developed, which predicts the global solar irradiance on a tilted surface, using as input data the total solar irradiance on a horizontal surface, the extraterrestrial radiation, the solar zenith angle and the solar incidence angle on a tilted plane. The comparison with the aforementioned models has shown that the neural network model, predicts more realistically the total solar irradiance on a tilted surface, as it performs better in regions where the other models show underestimation or overestimation in their calculations.

This paper proposed an improved incremental conductance method to track the Maximum Power Point (MPP) for PV Panel under fast changing solar irradiation. When there is increment in solar irradiation level, the conventional incremental conductance method is confused and responses incorrectly. The proposed method response correctly and there is no steady state oscillation compared to the conventional method. Matlab simulation is carried out for both the improved and conventional incremental conductance method under fast changing solar irradiation level. The simulation results showed the system able to track the MPP faster than the conventional method. © Published under licence by IOP Publishing Ltd.

iopscience.iop.org/1755-1315/16/1/012017

Photovoltaic system utilizes the naturally available solar energy without creating any negative effect on the environment. Solar energy is relatively available in different regions of the world and this makes it a very vital source of renewable energy. The exposure of the earth’s surface to the sun rays varies with the earth’s revolution and rotation and to get maximum energy from the sun, the incident solar beam must always be at 90o to the solar cells at all times. To achieve this, a solar tracker is required which senses the direction of the solar rays and adjusts the position of the solar panel accordingly. This paper is based on the design and implementation of an effective and low cost sensor-enabled solar tracking device which uses photo-sensors to detect sunlight and the measured intensity is read as input by a microcontroller which commands an actuator to change the position of the solar panel for maximum energy reception. The test results after design implementation shows ...

Solar energy is a large inexhaustible source of energy were the power from the sun intercepted by the Earth is over a trillion watt, which is many thousand times larger than the present consumption rate on the earth of all commercial energy sources. The sun could supply all the present and future energy need, presently the major way of extracting this energy is through solar panel and the efficiency of the energy conversion is in high consideration. Research has revealed that different factors can affect the efficiency of the panel, using a DT830B Digital Multi-meter and HTC-1 Clock/Temperature/Hygrometer on a Dp-Li21 polycrystalline solar panel. This work took the liberty of analyzing the effect of humidity and temperature on the efficiency of the solar panel. The result obtained shows that current production is highly aided by temperature within 42-45ºC and humidity below 35% and voltage production remains fairly stable with temperature below 42ºC and humidity below 60% while the power production is fairly stable with humidity below 40% and maximum with temperature at 45ºC, for power production on a panel mounted and to be mounted to be within maximum range, this analysis is to be carried out and put into consideration. Contribution/ Originality: This study contributes to the rectification of power fluctuation encountered in the use of solar panel, when the analysis is adopted and the recommendations are observed it will reduce the harmful effect the fluctuating power output has on the external connected devices.

Solar energy is a large inexhaustible source of energy were the power from the sun intercepted by the Earth is over a trillion watt, which is many thousand times larger than the present consumption rate on the earth of all commercial energy sources. The sun could supply all the present and future energy need, presently the major way of extracting this energy is through solar panel and the efficiency of the energy conversion is in high consideration. Research has revealed that different factors can affect the efficiency of the panel, using a DT830B Digital Multi-meter and HTC-1 Clock/Temperature/Hygrometer on a Dp-Li21 polycrystalline solar panel. This work took the liberty of analyzing the effect of humidity and temperature on the efficiency of the solar panel. The result obtained shows that current production is highly aided by temperature within 42-45ºC and humidity below 35% and voltage production remains fairly stable with temperature below 42ºC and humidity below 60% while the power production is fairly stable with humidity below 40% and maximum with temperature at 45ºC, for power production on a panel mounted and to be mounted to be within maximum range, this analysis is to be carried out and put into consideration. Contribution/ Originality: This study contributes to the rectification of power fluctuation encountered in the use of solar panel, when the analysis is adopted and the recommendations are observed it will reduce the harmful effect the fluctuating power output has on the external connected devices.