Simulation of the opti-physical parameters of selectives surfaces of absorber by the FDTD method. «applied to solar water heater»

Solar collectors are used for domestic water heating. They are used to collect and convert solar radiation into heat energy, by heating liquid water. One of the most important components of the solar collector is the absorber, which has to have selectivity in the wavelengths of the solar spectrum. This selectivity allows it to have a maximum of absorbance with a minimum of thermal radiation emitted .The objective of our work consists in characterizing these selective surfaces. A selective surface usually consists of a layer or a thin absorbing film in the solar and transparent spectrum in thermal infrared on a metallic support of a weak emission (substratum). We are interested in our work by the simulation of the opti-physical parameters of these selective surfaces using the FDTD method. The multi-scales (multi-ladders approach), led in this work, will first of all consists in studying the interactions between the electromagnetic waves and the microstructures whose characteristic scales will be close to the wavelength (microphone-scales). The directional and spectral selectivity caused by the microphone-structured surfaces will be modelled finely by solving the Maxwell's equations. The resolution of the Maxwell's equations will be undertaken using the F D T D method.