scholarly journals Modeling the Incident Solar Radiation of the City of N’Djamena (Chad) by the Capderou Method

2020 ◽  
Vol 2020 ◽  
pp. 1-10 ◽  
Author(s):  
Mahamat Hassane Babikir ◽  
Donatien Njomo ◽  
Mahamat Barka ◽  
Mahamoud Youssouf Khayal ◽  
Deli Goron ◽  
...  
Keyword(s):  
Solar Radiation ◽  
Diffuse Radiation ◽  
Theoretical Models ◽  
African Countries ◽  
Incident Solar Radiation ◽  
Diffuse Solar Radiation ◽  
Different Seasons ◽  
The Moment ◽  
Desert Climate

Chad is like many African countries with no meteorological station at the moment to measure solar radiation throughout the country. Thus, theoretical models are used to estimate incident solar radiation. These models are established in correlation form. Our objective was to present a model, which allows the determination of the solar component on two surfaces (horizontal and inclined). This model allowed us to determine, over time, the component of global, direct, and diffuse solar radiation over a period that will cover the different seasons of the year. The calculation is done according to Klein’s days over all the months of the year. The hourly results of the global, direct, and diffuse radiation obtained for all the planes going from January to December are satisfactory compared to the results of the other authors quoted in the literature, which give the maximum and minimum values very close to theirs. These results allowed us to validate the applicability of this model in a climate other than the desert climate.

Diffuse Sky Measurements and Determination of Corrected Shadow Band Multiplication Factors

1983 ◽  
Vol 105 (3) ◽  
pp. 305-310 ◽  
Author(s):  
W. D. Turner ◽  
A. M. Mujahid
Keyword(s):  
Solar Radiation ◽  
Correction Factor ◽  
Global Radiation ◽  
Diffuse Radiation ◽  
Monitoring Station ◽  
Radiation Measurement ◽  
Correction Factors ◽  
Diffuse Solar Radiation ◽  
Variable Factor

A meteorological monitoring station was operated at Blytheville, Arkansas, from April 1978 to April 1980. Direct normal, global, and diffuse sky radiation were monitored. From these data, models have been developed for the prediction of solar radiation, and discussions of several diffuse solar radiation models are included herein. Comparisons are made with these current diffuse models, and the correlation is quite good. In addition, instantaneous shadow band correction factors are presented which will allow a more accurate correction to be applied to the measured diffuse sky reading. The instantaneous correction factors are keyed to the global radiation measurement. Instead of applying a fixed correction factor to the diffuse measurement, regardless of sky condition, a variable factor can be applied. This will solve some of the current errors observed in diffuse measurements, because the current factors overpredict the diffuse radiation on cloudy days and underpredict the diffuse on clear days.

Improved Accuracy Models For Hourly Diffuse Solar Radiation

2005 ◽  
Vol 128 (1) ◽  
pp. 104-117 ◽  
Author(s):  
T. Muneer ◽  
S. Munawwar
Keyword(s):  
Solar Radiation ◽  
Regression Models ◽  
Global Radiation ◽  
Diffuse Radiation ◽  
Evaluation Procedure ◽  
Accuracy Score ◽  
Error Statistics ◽  
Diffuse Solar Radiation ◽  
Energy Applications ◽  
Extensive Evaluation

Solar energy applications require readily available, site-oriented, and long-term solar data. However, the frequent unavailability of diffuse irradiation, in contrast to its need, has led to the evolution of various regression models to predict it from the more commonly available data. Estimating the diffuse component from global radiation is one such technique. The present work focuses on improvement in the accuracy of the models for predicting horizontal diffuse irradiation using hourly solar radiation database from nine sites across the globe. The influence of sunshine fraction, cloud cover, and air mass on estimation of diffuse radiation is investigated. Inclusion of these along with hourly clearness index, leads to the development of a series of models for each site. Estimated values of hourly diffuse radiation are compared with measured values in terms of error statistics and indicators like, R2, mean bias deviation, root mean square deviation, skewness, and kurtosis. A new method called “the accuracy score system” is devised to assess the effect on accuracy with subsequent addition of each parameter and increase in complexity of equation. After an extensive evaluation procedure, extricate but adequate models are recommended as optimum for each of the nine sites. These models were found to be site dependent but the model types were fairly consistent for neighboring stations or locations with similar climates. Also, this study reveals a significant improvement from the conventional k-kt regression models to the presently proposed models.

Developing and Evaluation of Various Correlations for Diffuse Solar Radiation for Urla (Izmir, Turkey)

2012 ◽  
Vol 135 (2) ◽  
Author(s):  
Orhan Ekren
Keyword(s):  
Solar Radiation ◽  
Solar Energy ◽  
Tracking System ◽  
Diffuse Radiation ◽  
Energy System ◽  
Solar Irradiation ◽  
Total Solar Radiation ◽  
Total Radiation ◽  
Diffuse Solar Radiation ◽  
Tilted Surface

Characteristics of site-specific solar irradiation is required to optimize a solar energy system. If no tracking system is used, the amount of electricity or heat produced by solar energy depends on the total solar radiation on a tilted surface. Although pyranometer measures direct plus diffuse solar radiation on a horizontal surface, there are many locations where diffuse radiation is not measured. Also, diffuse radiation is necessary to determine the total radiation on a tilted surface. Therefore, in this study, new correlations for diffuse solar radiation is proposed as a function of atmospheric parameters for Urla (Izmir, Turkey). After applying the statistical procedure on the measured data, seven new correlations are proposed for the ratio of hourly average diffuse and total radiation. Also, the ratio of monthly average daily diffuse and total radiation for this region is proposed.

scholarly journals Coupling Diffuse Sky Radiation and Surface Albedo

2005 ◽  
Vol 62 (7) ◽  
pp. 2580-2591 ◽  
Author(s):  
Bernard Pinty ◽  
Alessio Lattanzio ◽  
John V. Martonchik ◽  
Michel M. Verstraete ◽  
Nadine Gobron ◽  
...  
Keyword(s):  
Solar Radiation ◽  
Land Surface ◽  
Surface Albedo ◽  
Climate Models ◽  
Diffuse Radiation ◽  
Atmospheric Model ◽  
Time Of Day ◽  
Mathematical Form ◽  
Diffuse Solar Radiation ◽  
Atmospheric Scattering

Abstract New satellite instruments have been delivering a wealth of information regarding land surface albedo. This basic quantity describes what fraction of solar radiation is reflected from the earth’s surface. However, its concept and measurements have some ambiguity resulting from its dependence on the incidence angles of both the direct and diffuse solar radiation. At any time of day, a surface receives direct radiation in the direction of the sun, and diffuse radiation from the various other directions in which it may have been scattered by air molecules, aerosols, and cloud droplets. This contribution proposes a complete description of the distribution of incident radiation with angles, and the implications in terms of surface albedo are given in a mathematical form, which is suitable for climate models that require evaluating surface albedo many times. The different definitions of observed albedos are explained in terms of the coupling between surface and atmospheric scattering properties. The analytical development in this paper relates the various quantities that are retrieved from orbiting platforms to what is needed by an atmospheric model. It provides a physically simple and practical approach to evaluation of land surface albedo values at any condition of sun illumination irrespective of the current range of surface anisotropic conditions and atmospheric aerosol load. The numerical differences between the various definitions of albedo for a set of typical atmospheric and surface scattering conditions are illustrated through numerical computation.

scholarly journals Surface global and diffuse solar radiation over China acquired from geostationary Multi-functional Transport Satellite data

2019 ◽  
Author(s):  
Hou Jiang ◽  
Ning Lu ◽  
Jun Qin ◽  
Ling Yao
Keyword(s):  
Solar Radiation ◽  
Satellite Data ◽  
Power Plants ◽  
Numerical Models ◽  
Regional Climate ◽  
Diffuse Radiation ◽  
Terrestrial Ecosystems ◽  
Global Solar Radiation ◽  
Surface Solar Radiation ◽  
Diffuse Solar Radiation

Abstract. Surface solar radiation drives the water cycle and energy exchange on the earth's surface, being an indispensable parameter for many numerical models to estimate soil moisture, evapotranspiration and plant photosynthesis, and its diffuse component can promote carbon uptake in ecosystems as a result of improvements of plant productivity by enhancing canopy light use efficiency. To reproduce the spatial distribution and spatiotemporal variations of solar radiation over China, we generate the high-accuracy radiation datasets, including global solar radiation (GSR) and the diffuse radiation (DIF) with spatial resolution of 1/20 degree, based on the observations from the China Meteorology Administration (CMA) and Multi-functional Transport Satellite (MTSAT) satellite data, after tackling the integration of spatial pattern and the simulation of complex radiation transfer that the existing algorithms puzzle about by means of the combination of convolutional neural network (CNN) and multi-layer perceptron (MLP). All data cover a period from 2007 to 2018 in hourly, daily total and monthly total scales. The validation in 2008 shows that the root mean square error (RMSE) between our datasets and in-situ measurements approximates 73.79 W/m2 (0.27 MJ/m2) and 58.22 W/m2 (0.21 MJ/m2) for GSR and DIF, respectively. Besides, the spatially continuous hourly estimates properly reflect the regional differences and restore the diurnal cycles of solar radiation in fine scales. Such accurate knowledge is useful for the prediction of agricultural yield, carbon dynamics of terrestrial ecosystems, research on regional climate changes, and site selection of solar power plants etc. The datasets are freely available from Pangaea at https://doi.org/10.1594/PANGAEA.904136 (Jiang and Lu, 2019).

Horizontal Tubular Microalgae Photobioreactor Plant View Factors and Diffuse Radiation

2011 ◽  
Vol 133 (2) ◽  
Author(s):  
T. Maor ◽  
J. Appelbaum
Keyword(s):  
Solar Radiation ◽  
Present Article ◽  
Diffuse Radiation ◽  
Design Parameters ◽  
View Factor ◽  
Diffuse Solar Radiation ◽  
Horizontal Tubes ◽  
Vertical Walls ◽  
View Factors

Different view factors and different components of the diffuse solar radiation impinging on a photobioreactor plant for cultivating microalgae products are formulated and calculated in the present article. The outdoor plant consists of multiple horizontal tubes arranged in multiple vertical walls. The diffuse radiation on a tube may come from three directions of the sky: from the aperture between the walls (from the sky above), from the penetration of the diffuse radiation between the tubes, and from the plant edges. Each component of the diffuse radiation is associated with a different view factor. For design parameters of a practical plant, the largest component of the diffuse radiation comes from the sky above the plant.

scholarly journals Monthly average daily diffuse solar radiation in Poland within the period 2005–2015

2018 ◽  
Vol 23 ◽  
pp. 00020
Author(s):  
Małgorzata Kleniewska ◽  
Dorota Mitrowska ◽  
Bogdan H. Chojnicki
Keyword(s):  
Solar Radiation ◽  
Linear Relationship ◽  
Global Radiation ◽  
Diffuse Radiation ◽  
Diffuse Fraction ◽  
Diffuse Solar Radiation ◽  
Monthly Average

In this paper an 11-year series of daily values of diffuse solar radiation registered at 8 actinometric stations in Poland was used to describe the characteristics of diffuse radiation and diffuse fraction of global radiation for the area of Poland. Based on the monthly average daily diffuse, global and extraterrestrial solar radiation a linear relationship between these elements was determined. The obtained equation enables the calculation of the monthly average daily diffuse solar radiation for Poland and the application of its values to further climatology studies.

scholarly journals Simulation of solar radiation during a total solar eclipse: a challenge for radiative transfer

2007 ◽  
Vol 7 (1) ◽  
pp. 499-535
Author(s):  
C. Emde ◽  
B. Mayer
Keyword(s):  
Solar Radiation ◽  
Radiative Transfer ◽  
Solar Eclipse ◽  
Monte Carlo Model ◽  
Three Dimensional ◽  
Diffuse Radiation ◽  
Radiative Transfer Model ◽  
Natural Phenomenon ◽  
Transfer Model ◽  
Diffuse Solar Radiation

Abstract. A solar eclipse is a rare but spectacular natural phenomenon and furthermore it is a challenge for radiative transfer modeling. Whereas a simple one-dimensional radiative transfer model with reduced solar irradiance at the top of the atmosphere can be used to calculate the brightness during partial eclipses a much more sophisticated model is required to calculate the brightness (i.e. the diffuse radiation) during the total eclipse. The reason is that radiation reaching a detector in the shadow gets there exclusively by horizontal (three-dimensional) transport of photons in a spherical shell atmosphere. In this study the first accurate simulations are presented examplified by the solar eclipse at 29 March 2006. Using a backward Monte Carlo model we calculated the diffuse radiation in the umbra and simulated the changing colors of the sky. Radiance and irradiance are decreased by 3 to 4 orders of magnitude, depending on wavelength. We found that aerosol has a comparatively small impact on the radiation in the umbra. We also estimated the contribution of the solar corona to the radiation under the umbra and found that it is negligible compared to the diffuse solar radiation in most parts of the spectrum. Spectrally resolved measurements in the umbra are not yet available. They are challenging due to the low intensity and therefore need careful planning. The new model may be used to support measurements during future solar eclipses.

scholarly journals Annual evolution of global, direct and diffuse radiation and fractions in tilted surfaces

2012 ◽  
Vol 32 (2) ◽  
pp. 247-260
Author(s):  
Adilson P. de Souza ◽  
João F. Escobedo ◽  
Alexandre Dal Pai ◽  
Eduardo N. Gomes
Keyword(s):  
Solar Radiation ◽  
Cloud Cover ◽  
Diffuse Radiation ◽  
Incident Radiation ◽  
Sao Paulo ◽  
Horizontal Surface ◽  
Direct Radiation ◽  
Incident Solar Radiation ◽  
Cover Ratio ◽  
Atmospheric Transmissivity

It was evaluated the annual evolution of global, direct and diffuse components of incident solar radiation on tilted surfaces to 12.85, 22.85 and 32.85º, facing north, in Botucatu, state of São Paulo, Brazil. The radiometric fractions were obtained for each component of the radiation in the aforementioned surfaces, through the ratio with the global and top of the atmosphere radiations. Seasonality was evaluated based on monthly averages of daily values. The measures occurred between 04/1998 and 07/2001 at 22.85º; 08/2001 and 02/2003 at 12.85º; and from 03/2003 to 12/2007 at 32.85º, with concomitant measures in the horizontal surface (reference). The levels of global and direct radiation on tilted surfaces were lower in summer and higher in the equinoxes when compared with the horizontal. The diffuse radiation on tilted surfaces was lower in most months, with losses of up to 65%. A trend of increasing differences occurred between horizontal and tilted surfaces with the increase of the angle in all the components and fractions of incident radiation. The annual evolution of rainfall and cloud cover ratio directly affected the atmospheric transmissivity of direct and diffuse components in the region.

scholarly journals Comparative Study of Experimentally Measured and Calculated Solar Radiations for Two Sites in Algeria

Energies ◽  
2021 ◽  
Vol 14 (21) ◽  
pp. 7441
Author(s):  
Bouazza Fekkak ◽  
Mustapha Merzouk ◽  
Abdallah Kouzou ◽  
Ralph Kennel ◽  
Mohamed Abdelrahem ◽  
...  
Keyword(s):  
Solar Radiation ◽  
Comparative Study ◽  
Theoretical Models ◽  
Relative Difference ◽  
Solar Irradiation ◽  
Comparison Study ◽  
Global Solar Irradiation ◽  
Proposed Model ◽  
Different Seasons

This paper presents a comparison study between the measured solar radiations on site and the calculated solar radiation based on the most theoretical models presented in the literature up to date. Indeed, for such purposes, this paper focusses on the analysis of the data of the measured solar radiation collected on two sites in Algeria such as Tlemcen (34°52′58″ N 01°19′00″ W, elevation 842 m) and Senia (35°39′ N 0°38′ W, elevation: 77 m). In order to check the accuracy of the proposed model, the experimental collected data of the solar radiation obtained from the existing radiometric stations installed at the two locations under investigation, are compared with the estimated or predicted solar radiations obtained from the Capderou and R.Sun models, where four days under clear skies are selected from different seasons to achieve this comparison. Second, the daily averages of the experimental global solar irradiation are compared to those predicted by Mefti model for both the sites. Finally, a validation is carried out based on the obtained experimental monthly global irradiations and with those estimated by Coppolino and Sivkov models. A relative difference is used in this case to judge the reliability and the accuracy of each model for both sites.

Sign in / Sign up

Export Citation Format

Share Document