EFFECT OF DIFFERENT NANOFLUIDS ON SOLAR RADIATION ABSORPTION
Suha Kareem Jebir†*, Noor Yehia Abbas‡, Ahmed F. Khudheyer††
†Lecturer, Department of Mechanical engineering, Engineering College, Al Nahrain University, Baghdad, Iraq
‡Lecturer, Department of Mechanical engineering, Engineering College, Al Nahrain University, Baghdad, Iraq
††Asst. Prof., Department of Mechanical engineering, Engineering College, Al Nahrain University, Baghdad, Iraq
Corresponding Author Email: Suha.K.Jebir@ced.nahrainuniv.edu.iq
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The use of solar thermal energy for water heating reduces the consumption of fossil fuels. The thermal fluids used in solar collectors have low thermal conductivity and a reduced capacity to absorb solar radiation in the visible range, where 48% of the total radiation is found. This work aims to develop various kinds of nanofluids and assess their effect on solar radiation absorption. For this reason, electron microscopy and UV-visible spectra characterize nanofluids. The thermal lead potential is measured with solar radiation obtaining the temperature profiles subjected to the nanodispersions. In addition, the effects of concentration, shape, degree of oxidation of graphene oxide (GO), the height of nanofluids are analyzed, and the properties of a hybrid nanofluid composed of GO with low oxidation with silver are evaluated. The ability to absorb visible light and the thermal conductivity of all synthesized nanofluids was enhanced compared with the deionized water. It is concluded that properties such as absorbance and transmittance do not allow evaluating the capacity for the conversion of radiation into the heat of nanofluids and the changes in these properties due to the effect of sunlight do not represent changes in the equilibrium temperature.