Optical properties of liquid paraffin contained with Al2O3 nanoparticles

The present work is to experimentally investigate the optical properties of liquid paraffin contained with Al2O3 nanoparticles for application in glazed envelope. Paraffin-based Al2O3 nanofluids were prepared through two-step method and its transmittance spectrum was measured by a TU-19 FTIR spectrometer. Based on the optical properties of liquid paraffin contained with Al2O3 nanoparticles obtained by model calculation, the changes of optical properties of liquid paraffin filled with and without Al2O3 nanoparticles are compared. The results show that compared with pure paraffin, the presence of Al2O3 nanoparticles decreases the transmittance of liquid paraffin by 15.7% in 5 mm optical path when the concentration is 0.001 vol%, and the nanofluids absorption coefficient is about 20.07 m−1 in the visible spectrum, which is almost 4 times that of pure paraffin. Meanwhile, the addition of Al2O3 nanoparticles makes the reflectivity of paraffin increase by 0.022. This conclusion is useful in analyzing glazed envelope contained Al2O3/paraffin nanofluids and provides a method of solar energy harvesting.