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It is mandatory to predict the hourly solar radiation received during the average day of each month for different solar energy applications, particularly in design methods, Scientists have developed methods to achieve this using differ-ent input parameters. The objective of this study is to compare statistically existing models for estimating the m...
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... As observed in Table 1, the current models are complex and required specialized scientists, as mentioned in [4]. On the other hand, early simplified models based on exponential functions were presented in [7,15,16]. However, those studies were limited to radiation and not to generated power, and further analysis were not found in the literature. ...
... To analyze the performance of the model, is required to determine the deviations that minimize the calculated error between the observed load profile (measured every 15 minutes) and the calculated instant power. Several empiric expressions to calculate those deviations are proposed by [7] for similar methods, presented in [15,16], but neither of them showed accurate approximations. A simple optimization was used to minimize the overall error in the instant power of the envelope curve and the results obtained using Eq. ...
... To visualize the model previously described, a normalized analysis of the average yearly curve will be performed, whose results are presented in Fig. 2. As can be seen, when using Eq. (6) to approach the envelope curve, there is a significant error near the sunrise and sunset, which is minimized using the error functions considered in Eq. (7). On the other hand, in both cases there are two error regions associated with the difference in the width of the bell. ...
Radiation forecast is the milestone of the solar energy industry, making possible the existence of the whole market. Solar radiation models allow scientists and engineers to predict the behaviour of a PV system to perform technical and economic analysis. Despite the existence of numerous models, most of them are highly complex or require massive amounts of data, limiting solar energy start-ups. As a result, a state-of-the-art review was performed and based on it this study proposed a simple model that allows emerging solar companies to create preliminary analysis for their clients. The proposed model calculates the instant power of the envelope curve of PV generation, based on the Gaussian bell equation, by using the daily specific energy and a deviation proportional to the sun hours of the geographical information as parameters. With accurate meteorological data, results showed an acceptable performance, with a more straightforward implementation, when compared against those reported in the literature.
... The measurement of solar radiation is always a necessary basis for the design of any solar energy conversion device and for a feasibility study of the possible use of solar energy. Measured data is the best, but may not always be available [23][24][25][26]. Knowledge of total solar radiation data is essential for researching and lowering the economic viability of systems that use solar energy [27]. ...
His work aims to develop a mathematical model of incident solar radiation on all the walls of a sloping roof habitat for a typical climate in the Ouagadougou region. Subsequently, we set up a program for the calculations of the essential parameters of illumination and the various components of solar radiation under the Fortran Programming Language and to plot our curves using the Origin software. This work allowed us to estimate the amount of solar flux that each wall of a habitat receives during a day, to know the importance of the orientation of the main facade of the habitat to the south and to find out how often the roof is exposed to solar radiation.
... Positive MBE and MPE values are indications of overestimation while negative values are suggestive of underestimation. A zero RMSE is ideal but it is usually positive(Ahmad and Tiwari, 2008;Kolebaje and Mustapha, 2012). This test can be used to compare a type of model performance to that of other predictive models. ...
Temperature is a major meteorological parameter driving most of the atmospheric processes vis-à-vis climate change. Therefore, a consistent model is necessary to achieve sustainable development goal 13 (SDG 13) known as climate action. Long-term monthly averages of surface temperature obtained from six southwest states in Nigeria were subjected to five mathematical models, namely the sum of two-Gaussians, the sum of two-Lorentzians, Fourier on four harmonics, Sine wave and Fourth-order polynomial functions. Statistical tools were used to examine the accuracy and fitness of the models. The evaluation showed that the Gaussian and Lorentzian models are good fits of the observed data. Furthermore, the performance indicators such as mean bias error (MBE), root mean square error (RMSE), mean percentage error (MPE) recorded the lowest values for Fourier on the fourth harmonic model. Similarly, its correlation coefficient, R, was the highest ranging from 0.95 to 1. Consequently, the Fourier model presented the best correlation with the observed data and hence recommended for predicting the temperature at the selected locations.
... The measurement of solar radiation is always a necessary basis for the design of any solar energy conversion device and for a feasibility study of the possible use of solar energy. The measured data are the best but cannot always be available [17][18][19][20]. Solar energy is mostly preferred due to being safe, clean, free, limitless and non-polluting. ...
... The measurement of solar radiation is always a necessary basis for the design of any solar energy conversion device and for a feasibility study of the possible use of solar energy. The measured data are the best but cannot always be available [17][18][19][20]. Solar energy is mostly preferred due to being safe, clean, free, limitless and non-polluting. ...
In the present research, we will estimation and test the applicability of the empirical models available for measured daily data of total solar radiation at Al-Baha, KSA (Lat. 200 01' N and Long. 410 28' E) from 2005 to 2017. The estimated models were comparative on the all of statistical testing parameters and t-test. Also, a comparative between the predicted and experimental data were performed. From experimental data, the maximum values occur of solar energy in the summer months, but the lowest values occur between winter and autumn months. The deviation between measured and estimated values does not exceed 6%. Different models (fifteen models) classified into five categories. The relative percentage error, regression constants, climate parameters and statistical analysis are discussed. From this variable parameter we observed a new simple linear model [(G/Go) = 0.175 + 0.265 (S/So) – 1.84(S/So)2] to estimate the total solar radiation Al-Baha site, KSA, and in other areas.
... Juhi Joshi and Vinit Kumar [18] estimate the monthly average global solar radiation using Angstrom Prescott model and to predict the solar radiation using ANN based on input sunshine hour, latitude, Kumar et al. [19] applied a new regression model for solar radiation estimation in hilly areas of North India by taking input sunshine duration only. To estimate the monthly average daily global solar radiation, four Indian stations solan, palampur, Amritsar and New Delhi are taken. ...
Solar energy is going to play a measure role in the future global energy supply. Its acceptance has already been on rise in developing countries like India, where there is acute shortage of energy due to economic and other climatic reasons. Forecasting or predicting the future output of solar energy is a much needed step to integrate high insolation of solar energy to the nation's power grid. Due to the fluctuating nature of solar energy, an efficient use is possible depending on reliable forecast information and its availability in various time and spatial scales. The current status of forecasting of solar irradiance for energy generation proposes a review of solar radiation prediction and its application in a rapidly increasing economy like India. Various models are developed for analysis which can be developed either by empirical, soft computing or by simulation approach.
... The existing daily global solar radiation decomposition models are mainly categorized in three groups. The first kind of models considers the effect of time [5]- [11]. In these models, only the time of day is included, which means that varying tendency in weather conditions is not considered. ...
Solar energy has come into prominence due to its sustainability, emission-free and ease of use considering the harmful nature of fossil resources in recent years. Accurate information on global radiation is essential to achieve the goal of planning and projection of a solar power system. Global solar radiation measurements provided by meteorology lack of reliability and some of the data are missing. At this point, global solar radiation estimation has an important role in designing energy systems that are based on solar energy. In this study, six different global radiation models are considered to estimate the monthly average hourly global radiation from the daily value in Çanakkale, which is located in the northwest of Turkey. The models are validated with hourly global radiation measurements provided by the Turkish State Meteorological Service. Based on the analysis of mean absolute bias error (MABE), root mean square error (RMSE), mean bias error (MBE) and t-statistical test, accuracy of the existing models is obtained. The results indicate that the Collares-Pereira and Rabl model modified by Gueymard (CPRG) is the most accurate one, and this model is proposed to obtain the hourly global radiation averaged over the months in elsewhere that has the similar climate with the northwest of Turkey.
... The first kind of models considers the solar hour angle, day length, solar time and local time. In this group, the Whillier model, Liu and Jordan model, Collares-Pereira and Rabl (CPR) model, CPRG model, Garg & Garg model and Gueymard model are included (Jamil Ahmad & Tiwari, 2008). Whillier (1956proposed a model to estimate hourly radiation values from daily values by assuming constant weather conditions as if there were no atmosphere. ...
Solar energy is the most important renewable energy resource that has become part of the solution to the world’s energy challenges. Global solar radiation data that provide information on how much energy arrives to the earth play a key role in solar energy applications because electricity generation from photovoltaic panels is directly affected by solar radiation. In general, global solar radiation measurements provided by meteorology are not easily available due to high equipment cost and technical requirements. At this point, accurate estimation of global solar radiation is essential for the design and performance evaluation of solar energy systems. In this study, eleven different global solar radiation estimation models are performed to estimate the hourly global solar radiation from the daily values in İki Eylül Campus in Eskişehir, which is located in the central region of Turkey. The models are validated with hourly global solar radiation measurements provided by a pyranometre of the controlled home placed in A.U. İki Eylül Campus. Based on the results of mean absolute bias error (MABE), root mean square error (RMSE), mean bias error (MBE) and t-statistical test, performance of the considered models is analyzed. The study shows that the Collares - Pereira and Rabl model modified by Gueymard (CPRG) has the best results, and this model is proposed to obtain the hourly global solar radiation averaged over the months in elsewhere that has the similar climate with the central regions of Turkey.
... A part of this radiation is absorbed, reflected and transferred by the atmospheric components. The determination of the solar irradiance fluxes magnitude at a given position on the Earth's surface is a function of various meteorological, astronomical and geographical parameters such as cloudiness, solar constant, solar elevation, Sun-Earth distance, albedo at ground, sunshine duration, day length, air temperature, Top of Atmosphere Radiation TOA, relative humidity, precipitation, and coefficient of absorption and diffusion by the atmospheric components [19][20][21][22][23][24][25][26][27][28][29][30][31][32][33]. Other parameters related to the solar radiation prediction have been widely given in the literature. ...
Over the years, some authors have used different models to estimate the solar radiation intensity over inclined surfaces, but none of them has tested and evaluated the accuracy of these models for various inclinations. In this study, by using the acquired data from Meteonorm, five best models studied previously by the authors have been used in order to predict the daily global solar radiation intensity DGSRI received on an inclined surface to the south and to evaluate the day by day performance of these models using a statistical analysis performed by several statistical indicators. The analysis of results revealed that the selected models haven’t the same accuracy, and it is concluded that there are models that can be preferred for the prediction of the DGSRI received on a tilted surface with different angle of inclination at the considered site, Tetuan city in northern Morocco. Empirical correlations between solar radiation intensity fallen on south-facing plane surfaces with various inclination and that receive on horizontal surfaces have been developed. As mean of results of the statistical indicator errors and excluding 20°, 60° and 70° inclinations and the coefficient of determination R² values, El Mghouchi model is performing comparatively better than the others for all inclinations ranging from 0° (horizontal plane) to 90° (vertical plane) in steps of 10°.
Thermal effects are significant loads for assessing concrete dam behaviour during operation. A new methodology to estimate thermal loads on concrete dams taking into account processes which were previously unconsidered, such as: the evaporative cooling, the night radiating cooling or the shades, has been recently reported. The application of this novel approach in combination with a three-dimensional finite element method to solve the heat diffusion equation led to a precise characterization of the thermal field inside the dam. However, that approach may be computationally expensive. This paper proposes the use of a new one-dimensional model based on an explicit finite difference scheme which is improved by means of the reported methodology for computing the heat fluxes through the dam faces. The improved model has been applied to a case study where observations from 21 concrete thermometers and data of climatic variables were available. The results are compared with those from: (a) the original one-dimensional finite difference model, (b) the Stucky-Derron classical one-dimensional analytical solution, and (c) a three-dimensional finite element method. The results of the improved model match well with the observed temperatures, in addition they are similar to those obtained with (c) except in the vicinity of the abutments, although this later is a considerably more complex methodology. The improved model have a better performance than the models (a) and (b), whose results present larger error and bias when compared with the recorded data.
