Solar Irradiance

The effects of solar radiations on physical properties and molecular structures of 200 nm polystyrene nanospheres (PSN) coated on silicon wafer were explored by field emission scanning electron microscope (FESEM) and attenuated total reflectance-Fourier transform infrared (ATR-FTIR) spectrometer. It is revealed the particles shape of PSN changed from spherical to dumbbell-like shape after solar irradiation. Reduction of the PSN size as much as 23.79% after 5 minutes exposure was also observed in PSN particles. We believed that some of the phenyl moieties of polystyrene broke down to facilitate carbon-carbon cross linkage bonds intra- as well as inter-PSN particles and were shown by ATR-FTIR spectrums. These results proven the shrinkage of PSN particles were caused by the change of the molecular structure of the irradiated PSN to be much more dense material.

In this work, a new kind of autonomous solar still is proposed. This construction is used in the arid countries with intense solar irradiation and has shortage of potable water. The goal was to concept and to build a physical and mathematical model of solar sea water distiller. The model design and the comparative simulations with the measurement results are carried out offline at the CUTEC Institute GmbH with the arithmetical and technical equipment available there

The need of solar irradiation forecast at a specific location over long time horizons has attained massive importance. In this paper, we study the machine learning techniques to predict solar irradiation in 10 min intervals using data sets from Killinochchi district, Faculty of Engineering, University of Jaffna measuring center. The accuracies of the prediction models such as ARIMA, Random Forest Regression, Neural Networks, Linear Regression and Supportive Vector Machine is compared. This study suggests that ARIMA performs well over other approaches.

Résumé -Ce travail concerne l'étude d'un circuit électronique pour le contrôle d'un système suiveur de soleil qui peut suivre le soleil même à puissance d'ensoleillement faible, surtout pour les journées à ciel couvert ou complètement couvert de nuages. Une réalisation d'un circuit électronique de contrôle et commande, ainsi qu'une réalisation mécanique d'un héliostat sont traitées. Enfin, une étude de l'éclairement solaire par le modèle de Brichambaut est comparée aux données expérimentales relevés par le système suiveur de soleil réalisé. Abstract -In this paper, we present a new electronic circuit which controls a sun tracker system even then with low solar radiation. An electronic circuit and a mechanical system were realised in the URERMS center of Adrar. A study for the Brichambaut's solar irradiance model is done, and compared with the measured irradiance using the sun tracker.

The use of daylighting in buildings and architecture is not new. Natural lighting became out of vogue due to the availability of cheap electricity, the predictability and the ability to control illumination levels due to artificial lighting. However, the alarm over rapid depletion of energy resources and the environmental effects of their applications have led designers to reuse daylighting strategies in buildings in order to minimise energy use for lighting and air conditioning as a result of heat gains from the daylight sources and the electrical fixtures. This paper describes a study on the savings achieved by using daylight in passive solar design of buildings and, in this case, the size of windows. Simulated exterior illuminance levels based on long term measured solar irradiation and cloud cover data were used to estimate interior illumination on normal working planes using simple building configurations. Illumination on these planes decreases the need for artificial lighting, thus energy can be saved. A simple algorithm was then used to calculate the overall cooling load to ascertain that the daylighting strategies used do not invoke an increase in thermal gains through walls and glazings. The findings from this study show that at least 10% savings can be produced from simple daylighting strategies.