Estimation of Daily Global and Diffuse Radiation for Braşov Urban Area, Romania
Journal Title: RECENT - Year 2011, Vol 12, Issue 33
Abstract
In order to calculate the performance of an existing solar energy conversion system or to estimate the energy generated by this, from the design stage, appropriate weather data are required. Unfortunately, there are not always recorded meteorological data, for all areas, what makes necessary the use of some solar radiation estimation methods. In this way, the conceiving of some mathematical models is required, if it is possible simple models, easy to implement in renewable systems design software or in building energy simulation software; thus, the determination of solar radiation data is important for studies. The proposed study is carried out in order to develop the monthly Ångström - Prescott equation coefficients from measured daily data for Braşov urban area and also to develop a monthly model for the diffuse radiation from daily clearness index. The models performance was evaluated by calculating three important statistical indicators: Mean Bias Error (MBE), Root Mean Square Error (RMSE) and t-statistic. The RMSE, MBE (and Mean Percentage Error, MPE) and t-statistic are the most used statistical indicators for the comparison and performance estimation of the solar irradiation models. These calculated statistical indicators concerning the total and diffuse radiations are very good for the proposed estimation models and all the conclusions are very useful in the solar energy conversion systems design.
Authors and Affiliations
Elena EFTIMIE
Keywords
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