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Thermal properties of carbon black aqueous nanofluids for solar absorption.

Han D, Meng Z, Wu D, Zhang C, Zhu H - Nanoscale Res Lett (2011)

Bottom Line: The results showed that the nanofluids of high-volume fraction had better photothermal properties.Both carbon black powder and nanofluids had good absorption in the whole wavelength ranging from 200 to 2,500 nm.Carbon black nanofluids had good absorption ability of solar energy and can effectively enhance the solar absorption efficiency.

View Article: PubMed Central - HTML - PubMed

Affiliation: College of Materials Science and Engineering, Qingdao University of Science and Technology, Qingdao, 266042, China. htzhu1970@163.com.

ABSTRACT
In this article, carbon black nanofluids were prepared by dispersing the pretreated carbon black powder into distilled water. The size and morphology of the nanoparticles were explored. The photothermal properties, optical properties, rheological behaviors, and thermal conductivities of the nanofluids were also investigated. The results showed that the nanofluids of high-volume fraction had better photothermal properties. Both carbon black powder and nanofluids had good absorption in the whole wavelength ranging from 200 to 2,500 nm. The nanofluids exhibited a shear thinning behavior. The shear viscosity increased with the increasing volume fraction and decreased with the increasing temperature at the same shear rate. The thermal conductivity of carbon black nanofluids increased with the increase of volume fraction and temperature. Carbon black nanofluids had good absorption ability of solar energy and can effectively enhance the solar absorption efficiency.

No MeSH data available.


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Photothermal properties of carbon black nanofluids. (a) Temperature as a function of time, (b) temperature enhancement as a function of time.
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Figure 3: Photothermal properties of carbon black nanofluids. (a) Temperature as a function of time, (b) temperature enhancement as a function of time.

Mentions: Figure 3a shows the temperatures of carbon black nanofluids and pure water as a function of the solar irradiation time. Figure 3b shows the temperature enhancement of nanofluids to pure water at the same irradiation time. It can be seen that the temperatures of the nanofluids increase more quickly than that of pure water. For example, within 42 min, the temperature of the 6.6 vol.% nanofluid increases from 24.4°C to 38.4°C while that of the pure water only increases to 31.2°C (Figure 3a). This indicates that carbon black nanofluids have good solar energy adsorption properties. It is clear that the nanofluids of high-volume fraction show higher temperatures, i.e., the solar adsorption ability enhances with the volume fraction in the experimental range (Figure 3). However, the temperature of 7.7 vol.% nanofluids is close to that of 6.6 vol.% sample, indicating that the photothermal properties will not change significantly when the volume fraction is higher than 6.6 vol.%. The temperature enhancements of carbon black nanofluids were higher than that of Mu's TiO2/water, SiO2/water, and ZrC/water nanofluids (<1 wt.%) [5], it is maybe due to the high concentration and good solar absorption of carbon black nanofluids (see the following section).


Thermal properties of carbon black aqueous nanofluids for solar absorption.

Han D, Meng Z, Wu D, Zhang C, Zhu H - Nanoscale Res Lett (2011)

Photothermal properties of carbon black nanofluids. (a) Temperature as a function of time, (b) temperature enhancement as a function of time.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC3211877&req=5

Figure 3: Photothermal properties of carbon black nanofluids. (a) Temperature as a function of time, (b) temperature enhancement as a function of time.
Mentions: Figure 3a shows the temperatures of carbon black nanofluids and pure water as a function of the solar irradiation time. Figure 3b shows the temperature enhancement of nanofluids to pure water at the same irradiation time. It can be seen that the temperatures of the nanofluids increase more quickly than that of pure water. For example, within 42 min, the temperature of the 6.6 vol.% nanofluid increases from 24.4°C to 38.4°C while that of the pure water only increases to 31.2°C (Figure 3a). This indicates that carbon black nanofluids have good solar energy adsorption properties. It is clear that the nanofluids of high-volume fraction show higher temperatures, i.e., the solar adsorption ability enhances with the volume fraction in the experimental range (Figure 3). However, the temperature of 7.7 vol.% nanofluids is close to that of 6.6 vol.% sample, indicating that the photothermal properties will not change significantly when the volume fraction is higher than 6.6 vol.%. The temperature enhancements of carbon black nanofluids were higher than that of Mu's TiO2/water, SiO2/water, and ZrC/water nanofluids (<1 wt.%) [5], it is maybe due to the high concentration and good solar absorption of carbon black nanofluids (see the following section).

Bottom Line: The results showed that the nanofluids of high-volume fraction had better photothermal properties.Both carbon black powder and nanofluids had good absorption in the whole wavelength ranging from 200 to 2,500 nm.Carbon black nanofluids had good absorption ability of solar energy and can effectively enhance the solar absorption efficiency.

View Article: PubMed Central - HTML - PubMed

Affiliation: College of Materials Science and Engineering, Qingdao University of Science and Technology, Qingdao, 266042, China. htzhu1970@163.com.

ABSTRACT
In this article, carbon black nanofluids were prepared by dispersing the pretreated carbon black powder into distilled water. The size and morphology of the nanoparticles were explored. The photothermal properties, optical properties, rheological behaviors, and thermal conductivities of the nanofluids were also investigated. The results showed that the nanofluids of high-volume fraction had better photothermal properties. Both carbon black powder and nanofluids had good absorption in the whole wavelength ranging from 200 to 2,500 nm. The nanofluids exhibited a shear thinning behavior. The shear viscosity increased with the increasing volume fraction and decreased with the increasing temperature at the same shear rate. The thermal conductivity of carbon black nanofluids increased with the increase of volume fraction and temperature. Carbon black nanofluids had good absorption ability of solar energy and can effectively enhance the solar absorption efficiency.

No MeSH data available.


Related in: MedlinePlus