Abstract:

The radiative properties of nano-sized particles play a significant role in a widely range of industrial and engineering applications, such as chemical, electric power, industry, meteorology, biomedicine, biophysics, astronomy, combustion, fire and flame, as well as solar power plants. In the thermal applications field, nanoparticles are found to be an effective electromagnetic wave absorbers within UV–Visible wavelength range; where, short wavelength radiations include high energy photons. Because of their excellent and unique thermo-optical properties which are the basis of thermal phenomena and energy conversion, nanoparticles are used as working media in solar thermal collectors for photo-thermal energy conversion. The purpose of the present study is to investigate the applicability of absorbing (conducting) and non-absorbing (dielectric) nanoparticles in photo-thermal energy conversion. These particles are dispersed in a media to produce nanoparticle suspensions. The comparison between the radiative properties of the two nanoparticles with their suspensions is carried out. The radiative properties include scattering, absorption as well as extinction coefficients which are the most important parameters in the capture and utilization of solar energy. The contribution of particle scattering in the radiation attenuation is investigated by computing the single scattering albedo. Through the analysis of the radiative and thermal behaviour of the particulate medium, it is clear that photothermal conversion is important to not only the solar thermal systems, but also to the electricity generation and solar chemical technology, in addition to the other applications. 

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