Details
Original language | English |
---|---|
Article number | 838 |
Journal | Nanomaterials |
Volume | 8 |
Issue number | 10 |
Early online date | 16 Oct 2018 |
Publication status | Published - Oct 2018 |
Abstract
Recently, several publications gave attention to nanofluid based solar absorber systems in which the solar radiation energy is directly absorbed in the volume of the fluid. This idea could provide advantages over conventionally used surface absorbers regarding the optical and thermal efficiency. For the evaluation of this concept, a numerical approach is introduced and validated in this contribution. The results show that the optical efficiency of a volumetric absorber strongly depends on the scattering behavior of the nanofluid and can reach competitive values only if the particle size distribution is narrow and small. If this is achieved, the surface temperature and therefore the heat loss can be lowered significantly. Furthermore, the surface absorber requires very high Reynolds numbers to transfer the absorbed energy into the working fluid and avoid overheating of the absorber tube. This demand of pumping power can be reduced significantly using the concept of volumetric absorption.
Keywords
- Anisotropy, Energy conversion, Nanofluid, Scattering, Solar absorption, Spectral penetration depth, Temperature distribution
ASJC Scopus subject areas
Cite this
- Standard
- Harvard
- Apa
- Vancouver
- BibTeX
- RIS
In: Nanomaterials, Vol. 8, No. 10, 838, 10.2018.
Research output: Contribution to journal › Article › Research › peer review
}
TY - JOUR
T1 - Radiation and Energetic Analysis of Nanofluid Based Volumetric Absorbers for Concentrated Solar Power
AU - Eggers, Jan Rudolf
AU - Lange, Eckart Matthias
AU - Kabelac, Stephan
N1 - Acknowledgments: The APC for the publication of this article was funded by the Open Access fund of Leibniz Universität Hannover.
PY - 2018/10
Y1 - 2018/10
N2 - Recently, several publications gave attention to nanofluid based solar absorber systems in which the solar radiation energy is directly absorbed in the volume of the fluid. This idea could provide advantages over conventionally used surface absorbers regarding the optical and thermal efficiency. For the evaluation of this concept, a numerical approach is introduced and validated in this contribution. The results show that the optical efficiency of a volumetric absorber strongly depends on the scattering behavior of the nanofluid and can reach competitive values only if the particle size distribution is narrow and small. If this is achieved, the surface temperature and therefore the heat loss can be lowered significantly. Furthermore, the surface absorber requires very high Reynolds numbers to transfer the absorbed energy into the working fluid and avoid overheating of the absorber tube. This demand of pumping power can be reduced significantly using the concept of volumetric absorption.
AB - Recently, several publications gave attention to nanofluid based solar absorber systems in which the solar radiation energy is directly absorbed in the volume of the fluid. This idea could provide advantages over conventionally used surface absorbers regarding the optical and thermal efficiency. For the evaluation of this concept, a numerical approach is introduced and validated in this contribution. The results show that the optical efficiency of a volumetric absorber strongly depends on the scattering behavior of the nanofluid and can reach competitive values only if the particle size distribution is narrow and small. If this is achieved, the surface temperature and therefore the heat loss can be lowered significantly. Furthermore, the surface absorber requires very high Reynolds numbers to transfer the absorbed energy into the working fluid and avoid overheating of the absorber tube. This demand of pumping power can be reduced significantly using the concept of volumetric absorption.
KW - Anisotropy
KW - Energy conversion
KW - Nanofluid
KW - Scattering
KW - Solar absorption
KW - Spectral penetration depth
KW - Temperature distribution
UR - http://www.scopus.com/inward/record.url?scp=85056325469&partnerID=8YFLogxK
U2 - 10.3390/nano8100838
DO - 10.3390/nano8100838
M3 - Article
AN - SCOPUS:85056325469
VL - 8
JO - Nanomaterials
JF - Nanomaterials
SN - 2079-4991
IS - 10
M1 - 838
ER -