| 摘要 |
Disclosed is a method for preparing a nanofluid comprising: a crushing step of crushing a carbon nanotube with a dispersant; and a homogenizing step of adding a solvent to the material obtained from the crushing step to be homogenized. Additionally, disclosed is the nanofluid including the carbon nanotube, the dispersant, and water, and having one or more characteristics mentioned below. i) A dispersion stability characterized by having less than 10% of a decrease rate of an extinction coefficient value over the lapse of time, compared to an initial value in the case that the nanofluid is placed at room temperature in the predetermined space for equal to or longer than 25 days. ii) A high-temperature stability characterized by having less than 10% of the decrease rate of the extinction coefficient value compared to an initial value in the case that the nanofluid is heated at 80°C for 12 hours. iii) An optical transmittance characterized by being equal to or less than 0.05 (pure water 1.0 basis) at wavelength of 200 to 1400nm measured by UV/Vis/NIR array spectrophotometer in the case that content of the carbon nanotube is present in a volume percentage of 0.003 based on the total volume of the nanofluid. iv) An optical transmittance characterized by being equal to or less than 0.02 (pure water 1.0 basis) of at wavelength of 200 to 1400nm measured by UV/Vis/NIR array spectrophotometer in the case that the content of the carbon nanotube is present in a volume percentage of 0.005 based on the total volume of the nanofluid. Thus, the nanofluid has an effect of being effectively utilized in a solar collector, especially in the direct absorption-type solar collector since the nanofluid herein is a working fluid for exchanging and storing heat and has the superior dispersion stability and a light absorbing capacity. Furthermore, the nanofluid has advantages of saving time and expense of preparing, and being prepared safely as the method for manufacturing nanofluid is simplified. |
