scholarly journals Solar radiation characteristics at Qena / Egypt

MAUSAM ◽  
2021 ◽  
Vol 49 (1) ◽  
pp. 59-70
Author(s):  
SAYED M. EL-SHAZL ◽  
Y.A.M. ABDELMAGEED ◽  
M. EL-NOUBI ADAM
Keyword(s):  
Solar Radiation ◽  
Global Solar Radiation ◽  
Dust Particles ◽  
Atmospheric Conditions ◽  
Climatic Effects ◽  
Study Region ◽  
Frequency Distributions ◽  
Diffuse Fraction ◽  
Low Degree ◽  
Aerosol Dust

Measurements of the hourly global solar radiation (G) and its diffuse component (D) on a horizontal surface have been carried out in Qena / Upper Egypt in the period from June 1992 to May 1993. The corresponding diffuse fraction (DIG) is calculated. Diurnal variations of the results have been studied. Also the daily totals values and its monthly and seasonal averages as well as their frequency distributions were computed and examined. The seasonal and climatic effects on the fluctuation of the results are discussed. These effects were particularly large during spring and Winter months owing to the high fluctuation of the atmospheric conditions with aspect to amount of clouds, water content, and concentration of aerosol dust particles. The influence of clouds is also considered. It shows small effect on the results (4.5%), reflecting the low degree of cloudiness in the study region. The relation between the diffuse fraction and clearness index (G/Go) shows that most of the points lies in the region of the high availability of the incoming solar radiation. In general the study shows clearly the abundance of solar energy in Qena / Egypt, and the suitability of its climate for using it in different applications.

scholarly journals Analysis of Measurements of Direct Normal and Global Solar Radiation for Maceió, Alagoas State, Northeastern Brazil

2020 ◽  
Vol 35 (4) ◽  
pp. 659-674
Author(s):  
José Marcelo Lopes Júnior ◽  
José Leonaldo de Souza ◽  
Ricardo Araujo Ferreira Junior ◽  
Cícero Manoel dos Santos ◽  
Gustavo Bastos Lyra ◽  
...  
Keyword(s):  
Solar Radiation ◽  
Solar Irradiance ◽  
Cloud Cover ◽  
Global Solar Radiation ◽  
Northeastern Brazil ◽  
Human Knowledge ◽  
Clearness Index ◽  
Study Region ◽  
Maximum Value ◽  
Sky Conditions

Abstract Studying solar radiation is essential for human knowledge, since it is present in practically all its activities. Thus, the aim of this work was to analyze the climatic and seasonal variation of direct normal and global solar radiation in the region of Maceió, Alagoas State, Northeastern Brazil with sky conditions characterized by clearness index (Kt). The Kt was determined by the ratio between global solar irradiance and solar irradiance at the top of the atmosphere. The highest occurrences of daily direct normal solar irradiance under conditions of Kt ≥ 0.6 were recorded between 400 W m−2 and 700 W m−2 for all seasons. Under conditions of 0.4 ≤ Kt < 0.6, the daily direct normal solar irradiance occurred between 200 W m−2 and 500 W m−2 and for conditions of Kt < 0.4, its maximum value was 200 W m−2. It was observed that the levels of solar incidence in the study region depend on cloud cover conditions, with little influence of seasonality.

scholarly journals COEFICIENTES DE ANGSTRÖM-PRESCOTT PARA ESTIMAR A RADIAÇÃO SOLAR GLOBAL EM CAMPOS DOS GOYTACAZES, RJ

Irriga ◽  
2020 ◽  
Vol 25 (3) ◽  
pp. 481-491
Author(s):  
José Carlos Mendonça ◽  
Andre Dalla Bernardina Garcia ◽  
Jonathan Nogueira Franco
Keyword(s):  
Solar Radiation ◽  
Meteorological Data ◽  
Global Radiation ◽  
Absolute Error ◽  
Maximum Error ◽  
Global Solar Radiation ◽  
Study Region ◽  
Emax Model ◽  
Mass Coefficient ◽  
The City

COEFICIENTES DE ANGSTRÖM-PRESCOTT PARA ESTIMAR A RADIAÇÃO SOLAR GLOBAL EM CAMPOS DOS GOYTACAZES, RJ     JOSÉ CARLOS MENDONÇA¹; ANDRE DALLA BERNARDINA GARCIA² E JONATHAN NOGUEIRA FRANCO³   ¹ Laboratório de Engenharia Agrícola – LEAG, Universidade Estadual do Norte Fluminense Darcy Ribeiro, Av. Alberto Lamego, 2000, Parque Califórnia, Campos dos Goytacazes, RJ, Brasil. [email protected] ² Laboratório de Engenharia Agrícola – LEAG, Universidade Estadual do Norte Fluminense Darcy Ribeiro, Av. Alberto Lamego, 2000, Parque Califórnia, Campos dos Goytacazes, RJ, Brasil. [email protected] ³ Laboratório de Engenharia Agrícola – LEAG, Universidade Estadual do Norte Fluminense Darcy Ribeiro, Av. Alberto Lamego, 2000, Parque Califórnia, Campos dos Goytacazes, RJ, Brasil. [email protected]     1 RESUMO   Para reduzir custos com equipamentos utilizados na estimativa da radiação solar, geralmente são realizadas estimativas a partir de um modelo utilizando a irradiância solar, como Angström-Prescott. Esse trabalho teve por objetivo obter os coeficientes, mensais, utilizados na equação de Angström-Prescott para estimativa da Radiação Solar Global no município de Campos dos Goytacazes, RJ. Foram utilizados dados meteorológicos entre os anos de 1998 a 2020 para obtenção dos valores de horas de insolação (n), máximo de horas de insolação diária (N), radiação solar global no topo da atmosfera (Ra) e radiação solar global (Rs) mensalmente estimados. Os resultados foram validados por meio dos índices de concordância (D), erro médio absoluto (MAE), erro máximo (EMAX), eficiência do modelo ou método (EF), índice de desempenho (c) e coeficiente residual de massa (CRM). Para a região de estudo, os coeficientes “a” e “b” encontrados foram 0,0191 e 0,9486, respectivamente, considerando-se os valores anuais. Os índices estatísticos “D” e “c” foram 0,977 e 0,94, respectivamente, sendo classificados como ótimos. A partir dos resultados e obtidos é possível utilizar apenas um heliógrafo para estimar a radiação global com ótima precisão, em cada um dos meses individualmente, para a cidade de Campos dos Goytacazes.   Palavras-chave: climatologia, agrometeorologia, modelagem.     MENDONÇA, J. C., GARCIA, A. D. B., FRANCO, J. N. MONTHLY ANGSTRÖM-PRESCOTT COEFFICIENTS TO ESTIMATE GLOBAL SOLAR RADIATION IN CAMPOS DOS GOYTACAZES, RJ     2 ABSTRACT   To reduce costs with equipment used to estimate solar radiation, estimates are usually made based on a  model that uses solar irradiance, such as Angström-Prescott. This work aimed to obtain monthly coefficients, using the Angström-Prescott equation to estimate Global Solar Radiation in the city of Campos dos Goytacazes, RJ. Meteorological data from 1998 to 2020 were used to obtain values ​​of hours of sunshine (n), maximum hours of daily sunshine (N), global solar recording at the top of the atmosphere (Ra) and global solar radiation (Rs) monthly estimated. The results were validated using  agreement indexes (D), mean absolute error (MAE), maximum error (EMAX), model or method efficiency (EF), performance index (c) and residual mass coefficient (CRM). For the study region, coefficients "a" and "b" found were 0.0191 and 0.9486, respectively, considering the annual values. The statistical indexes "D" and "c" were 0.977 and 0.94, respectively, and were classified as great. Based on the results, it is possible to use only a heliograph to estimate global radiation with maximum precision, in each month, individually, for the city of Campos dos Goytacazes.   Keywords: climatology, agrometeorology, modeling.

scholarly journals Potential of Wind and Solar Electricity Generation in Bangladesh

2012 ◽  
Vol 2012 ◽  
pp. 1-10 ◽  
Author(s):  
Sanjoy Kumar Nandi ◽  
Mohammad Nasirul Hoque ◽  
Himangshu Ranjan Ghosh ◽  
Swapan Kumar Roy
Keyword(s):  
Solar Radiation ◽  
Alternative Energy ◽  
Sunshine Duration ◽  
Global Solar Radiation ◽  
Environmental Benefits ◽  
Wind Data ◽  
Energy Sources ◽  
Energy Potential ◽  
Frequency Distributions ◽  
Wind Speeds

Wind and solar energies are the alternative energy sources that can be used to supplement the conventional energy sources particularly in Bangladesh. In this work, the aim is to assess the current wind and solar energy potential in Bangladesh. The wind data for the five stations obtained from Local Government Engineering Department have been assessed, but only two of them seem to be eligible for energy production. Annual average, monthly average, and hourly average wind speeds and wind power densities were calculated from the wind data. The Weibull distribution parameters (c and k), the dominant wind directions, and the frequency distributions were also determined. Experimentally measured solar radiation data are not available over Bangladesh. Measured climatological data such as cloud cover and sunshine duration data of Bangladesh Meteorological Department from 1992 to 2001 used for the estimation of global solar radiation as they are correlated. Technoeconomic feasibility analysis is done for 100 kW grid connected wind and solar photovoltaic (PV) systems. Renewable-energy-based system will bring more environmental benefits than conventional power in terms of human health, reduction of air pollution, and decrease of noise, and so forth. However, in the above estimation, these were not considered.

scholarly journals Monthly, Seasonal and Yearly Assessments of Global Solar Radiation, Clearness Index and Diffuse Fractions in Alice, South Africa

2021 ◽  
Vol 13 (4) ◽  
pp. 2135
Author(s):  
Oliver O. Apeh ◽  
Ochuko K. Overen ◽  
Edson L. Meyer
Keyword(s):  
South Africa ◽  
Solar Radiation ◽  
Solar Energy ◽  
Power Plants ◽  
Fossil Fuels ◽  
Global Solar Radiation ◽  
Clearness Index ◽  
Diffuse Fraction ◽  
Average Percentage ◽  
Coal Power Plants

The constant scheduled load shedding in South Africa has commonly been executed in an attempt to maintain the long aging coal power plants in the country. With the rise in the reduction of fossil fuels, efforts to eradicate environmental hazards of carbon through solar photovoltaic (PV) resources to their complete prospect are in progress. South Africa, and in particular the town Alice, acquires sunshine annually, making it appropriate to harvest solar energy. This work aims to characterize solar radiation, clearness index (Kt), and diffuse fraction (Kd) in Alice, South Africa. Hourly global and diffuse solar irradiance were estimated into monthly, seasonal, and yearly variations of Kt and Kd for the years 2017–2020. The range of values for describing the daily classification of sky condition was centered on earlier studies. The cumulative frequency and frequency distribution of daily Kt was analyzed statistically in an individual month. The analyses show that the average percentage frequency of Kt within the period is 11.72% of the cloudy days, 57% of partially cloudy days, and 31.28% of clear sky days. The findings of this research show that Alice remains a key contender for solar energy conversion location, owing to its reasonably high frequency (Kt > 0.40) of clear and partially cloudy skies. Hence, it is essential to establish energy-efficiency for energy consumption and also for daily performances.

scholarly journals Empirical models for estimation of global solar radiation using the monthly average daily sunshine hours data for Makurdi, Benue State

2020 ◽  
Vol 12 (1) ◽  
pp. 32-39
Author(s):  
R.S. Sa’id ◽  
S.I. Akor ◽  
U.M. Gana
Keyword(s):  
Solar Radiation ◽  
Diffuse Radiation ◽  
Global Solar Radiation ◽  
Climatic Conditions ◽  
Empirical Models ◽  
Coefficient Of Determination ◽  
Linear Quadratic ◽  
Diffuse Fraction ◽  
Correlation Models ◽  
Sunshine Hours

This paper proposes empirical correlation models for estimating global solar radiation using data of sunshine hours for the location of Makurdi in Benue State of Nigeria. The paper suggests extrapolation of the empirical models for other locations with similar climatic conditions. The proposed models are: Linear, Quadratic, Cubic, Exponential, Power and Logarithmic models. Each of the models is based on Angstrom-Prescott equations for estimating global solar radiation. Any of the models can ease the use of sophisticated equipments, which are expensive, delicate and sometimes develop faults during measurement. The results of the models show that the cubic model is the best with slightly higher coefficient of  determination. The coefficient of  determination of each of the models was found to be 0.952, 0.965, 0.967, 0.965, 0.948& 0.924 respectively, while the absolute correlation was found to be unity. Errors evaluated include MBE, RMSE and MPE with minimal values. The percentage diffuse and direct solar radiations, clearness index and the diffuse fraction were also estimated using the models. The results of the estimations done using the proposed models indicate that there is an estimated average annual global solar radiation of 6056MJm-2, monthly value of 505MJm-2 and daily insolation of 16.82MJm-2 sufficient enough for maximum solar radiation exploitation. Keywords: Solar Radiation, Empirical Models, Diffuse Radiation, Direct Radiation

Comparative study of various correlations in estimating hourly diffuse fraction of global solar radiation

2006 ◽  
Vol 31 (15) ◽  
pp. 2492-2504 ◽  
Author(s):  
C.P. Jacovides ◽  
F.S. Tymvios ◽  
V.D. Assimakopoulos ◽  
N.A. Kaltsounides
Keyword(s):  
Solar Radiation ◽  
Comparative Study ◽  
Global Solar Radiation ◽  
Diffuse Fraction

Influence of trees on the energy consumption of a social housing in mid-western Brazil

2019 ◽  
pp. 53-65
Author(s):  
Renata Domingos ◽  
Emeli Guarda ◽  
Elaise Gabriel ◽  
João Sanches
Keyword(s):  
Energy Consumption ◽  
Solar Radiation ◽  
Thermal Comfort ◽  
Air Conditioning ◽  
Computational Simulation ◽  
Building Energy ◽  
General Idea ◽  
Heat Island ◽  
Study Region ◽  
Ample Evidence

In the last decades, many studies have shown ample evidence that the existence of trees and vegetation around buildings can contribute to reduce the demand for energy by cooling and heating. The use of green areas in the urban environment as an effective strategy in reducing the cooling load of buildings has attracted much attention, though there is a lack of quantitative actions to apply the general idea to a specific building or location. Due to the large-scale construction of high buildings, large amounts of solar radiation are reflected and stored in the canyons of the streets. This causes higher air temperature and surface temperature in city areas compared to the rural environment and, consequently, deteriorates the urban heat island effect. The constant high temperatures lead to more air conditioning demand time, which results in a significant increase in building energy consumption. In general, the shade of the trees reduces the building energy demand for air conditioning, reducing solar radiation on the walls and roofs. The increase of urban green spaces has been extensively accepted as effective in mitigating the effects of heat island and reducing energy use in buildings. However, by influencing temperatures, especially extreme, it is likely that trees also affect human health, an important economic variable of interest. Since human behavior has a major influence on maintaining environmental quality, today's urban problems such as air and water pollution, floods, excessive noise, cause serious damage to the physical and mental health of the population. By minimizing these problems, vegetation (especially trees) is generally known to provide a range of ecosystem services such as rainwater reduction, air pollution mitigation, noise reduction, etc. This study focuses on the functions of temperature regulation, improvement of external thermal comfort and cooling energy reduction, so it aims to evaluate the influence of trees on the energy consumption of a house in the mid-western Brazil, located at latitude 15 ° S, in the center of South America. The methodology adopted was computer simulation, analyzing two scenarios that deal with issues such as the influence of vegetation and tree shade on the energy consumption of a building. In this way, the methodological procedures were divided into three stages: climatic contextualization of the study region; definition of a basic dwelling, of the thermophysical properties; computational simulation for quantification of energy consumption for the four facade orientations. The results show that the façades orientated to north, east and south, without the insertion of arboreal shading, obtained higher values of annual energy consumption. With the adoption of shading, the facades obtained a consumption reduction of around 7,4%. It is concluded that shading vegetation can bring significant climatic contribution to the interior of built environments and, consequently, reduction in energy consumption, promoting improvements in the thermal comfort conditions of users.

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