Open AccessEstimation of Global Solar Radiation Using NNARX Neural Networks Based on the UV Index
Author(s) -
John Barco Jiménez,
Francisco Eraso-Checa,
Andrés Pantoja,
Eduardo Caicedo
Publication year - 2021
Publication title -
tecnura
Language(s) - English
Resource type - Journals
eISSN - 2248-7638
pISSN - 0123-921X
DOI - 10.14483/22487638.18638
Subject(s) - mean squared error , artificial neural network , context (archaeology) , coefficient of determination , index (typography) , estimation , statistics , mathematics , computer science , data mining , artificial intelligence , geography , engineering , systems engineering , world wide web , archaeology
Context: This work presents different models based on artificial neural networks, among them NNARX, for estimating global solar radiation from UV index measurements. The objective is to determine the efficiency of the models studied to estimate global solar radiation in terms of the coefficient of determination (R2), the root-mean-square error (RMSE), and the mean absolute error (MAE).Methodology: It is divided into four stages: i) conformation of the training dataset (in this case, it uses a training set of 213.019 data collected over five years in the city of Pasto, Colombia, with the Davis Vantage Pro 2.0 station); ii) pre-processing of data to remove erroneous and unusual data; iii) definition of models based on recurrent and conventional artificial neural networks according to an analysis of topologies, e.g. NNFIR and NNARX; iv) training of the models and evaluation of the estimation efficiency through metrics such as R2, RMSE, and MAE. To validate the model, a new dataset collected during the last year was used, which was not included in the data training.Results: The global solar radiation estimation models based on NNARX show the best estimation efficiency compared to conventional neural networks. The NNARX221 model has an RMSE of 54,32 and a MAE of 18,06 w/m2.Conclusions: NNARX models are highly efficient at estimating global solar radiation, with a coefficient of determination of 0,9697 in the best of cases. The most efficient models are characterized by using two past times and the current UV index instant, and they feed from two past times of their own estimated radiation output. Furthermore, the numerical results show that the contribution of temperature and relative humidity is not relevant to improving the efficiency of the estimation of global solar radiation. These models can be particularly important since they only use measurements made with UV index sensors, which are less expensive than solar radiation ones.