TY - JOUR
T1 - A review of nanofluid-based direct absorption solar collectors
T2 - Design considerations and experiments with hybrid PV/Thermal and direct steam generation collectors
AU - Goel, Nipun
AU - Taylor, Robert A.
AU - Otanicar, Todd
N1 - Publisher Copyright:
© 2019 Elsevier Ltd
PY - 2020/1
Y1 - 2020/1
N2 - Over the last 100 plus years, solar thermal energy has been used for residential heating applications, industrial process heating, electricity generation, and thermochemical reactions. Because of the vast number of applications, numerous designs have been developed to improve the efficiency of converting incoming solar energy into useful heat and to lower the cost. Conventional solar thermal collectors required a solid surface to absorb and convert incoming solar energy to useful thermal energy. Developments in materials science have enabled a new type of absorber—a volumetric absorber—which utilizes nanoparticles suspended in a fluid to absorb sunlight. Since most working fluids only weakly absorb sunlight, well-engineered ‘nanofluids’ are attractive because only a low volume fraction of nanoparticles is needed to obtain a large shift in the optical properties. This review, on the 10-year anniversary of the first appearance of nanofluid-based direct absorption solar thermal collectors, provides a forward-looking perspective on the challenges and opportunities associated with nanofluids as direct absorbers. Through a critical comparison of design considerations, as well as the most recent experimental results of less well explored areas like hybrid photovoltaic/thermal systems and direct steam generation, this review aims to provide discourse on the next steps for development.
AB - Over the last 100 plus years, solar thermal energy has been used for residential heating applications, industrial process heating, electricity generation, and thermochemical reactions. Because of the vast number of applications, numerous designs have been developed to improve the efficiency of converting incoming solar energy into useful heat and to lower the cost. Conventional solar thermal collectors required a solid surface to absorb and convert incoming solar energy to useful thermal energy. Developments in materials science have enabled a new type of absorber—a volumetric absorber—which utilizes nanoparticles suspended in a fluid to absorb sunlight. Since most working fluids only weakly absorb sunlight, well-engineered ‘nanofluids’ are attractive because only a low volume fraction of nanoparticles is needed to obtain a large shift in the optical properties. This review, on the 10-year anniversary of the first appearance of nanofluid-based direct absorption solar thermal collectors, provides a forward-looking perspective on the challenges and opportunities associated with nanofluids as direct absorbers. Through a critical comparison of design considerations, as well as the most recent experimental results of less well explored areas like hybrid photovoltaic/thermal systems and direct steam generation, this review aims to provide discourse on the next steps for development.
KW - Direct absorption
KW - Direct steam generation
KW - Hybrid photovoltaic/thermal
KW - Nanofluids
KW - Nanoparticles
KW - Volumetric
UR - http://www.scopus.com/inward/record.url?scp=85067797697&partnerID=8YFLogxK
U2 - 10.1016/j.renene.2019.06.097
DO - 10.1016/j.renene.2019.06.097
M3 - Article
AN - SCOPUS:85067797697
SN - 0960-1481
VL - 145
SP - 903
EP - 913
JO - Renewable Energy
JF - Renewable Energy
ER -