Techno- thermo- economic- environmental assessment of parabolic trough collectors using hybrid nanofluids

ABSTRACT

This study was motivated by the need to enhance the performance of parabolic trough collectors (PTCs) used in various industrial applications. The investigation aimed to explore the potential of using synthetic aromatic fluids with hybrid nanoparticles to achieve improved thermal efficiency and heat transfer in PTC systems. The combination of four industrial synthetic aromatic fluids, namely Syltherm 800, Therminol VP1, Therminol 66, and Dowtherm A, with hybrid nanoparticles consisting of Al₂O₃ and TiO₂ with a combined volume concentration of 3% (50:50 ratio), was studied due to their widespread industrial application and potential for performance enhancement. The mathematical model is developed using Engineering Equation Solver (EES) and validated against results from Sandia National Laboratory (SNL), showing an average uncertainty of 0.1% for outlet temperature and 1.33% for thermal efficiency. The findings indicate that the hybrid nanofluid exhibits substantial enhancements in thermal efficiency compared to the base fluids. The enhancements are observed for Syltherm 800 (1.1%), Therminol VP1 (1.243%), Therminol 66 (1.04%), and Dowtherm A (0.2%). The heat transfer coefficient (HTC) increases by 206.35%, 156.63%, 220%, and 250% for Syltherm 800, Therminol VP1, Therminol 66, and Dowtherm A, respectively. In addition, enviroeconomic analysis and exergoenviroeconomic analysis are performed, revealing that the Therminol VP1-based nanofluid exhibits the lowest daily cost among the investigated fluids. The study’s findings highlight the potential of using synthetic aromatic fluids with hybrid nanoparticles to improve the performance of parabolic trough collectors.

KEYWORDS:

• Thermal efficiency
• exergy
• environment
• solar energy
• nanofluid

Nomenclature

Abbreviation:	=
DAPTSC:	=	Direct Absorption Parabolic Trough Solar Collector
DNI:	=	Direct Normal Irradiance
HTC:	=	Heat transfer coefficient
HTF:	=	Heat Transfer Fluid
Lpm:	=	Liter per minute
PTC:	=	Parabolic Trough Collector
Symbols:	=
${\mathrm{A}}_{\mathrm{a}\mathrm{p}}$	=	Aperture Area of solar collector [m2]
${\mathrm{A}}_{\mathrm{c}}$	=	Collector area
${\mathrm{F}}_{\mathrm{r}}$	=	Heat Removal Factor
${\mathrm{Q}}_{\mathrm{u}}$	=	Useful heat gain from the collector [W]
${\mathrm{h}}_{\mathrm{r}}$	=	Radiative Heat Transfer Coefficient in air
⋴	=	Emissivity of the absorber tube
µ	=	Dynamic Viscosity [Pa-s]
A	=	Area [m2]
C	=	Cost [$]
cp	=	Specific heat capacity [J/kgoC]
Gb	=	Direct normal irradiance
h	=	Convective Heat Transfer Coefficient [W/m2oC]
Nu	=	Nusselt Number
Ql	=	Heat loss [W]
Qs	=	Solar absorbed heat [W]
T	=	Temperature [oC]
η	=	Efficiency
φ:	=	Volume Concentration
$\mathrm{R}\mathrm{e}$	=	Reynolds Number
$\mathrm{k}$	=	Thermal Conductivity [W/moC]
$\rho$	=	Density [kg/m3]
Subscript	=
a	=	Ambient
bf	=	Base fluid
ex	=	Exergetic
hnf	=	Hybrid nanofluid
i	=	Inlet
o	=	Outlet
r	=	Receiver
therm	=	Thermal
w	=	Wind

Disclosure statement

The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper.

Additional information

Notes on contributors

Santosh Kumar Singh

Santosh Kumar Singh is an Research Scholar in the Department of Mechanical Engineering, Institute of Engineering & Technology, Lucknow. His area of research is solar thermal energy and nanofluidics.

Arun Kumar Tiwari

Dr. Arun Kumar Tiwari is an Professor in the Department of Mechanical Engineering, Institute of Engineering & Technology, Lucknow. He has published more than 107 SCI/Scopus indexed papers in the field of solar thermal energy and nanofluidics, he has been recognized in Top 2% World Scientists, 2022 (Published by: Elsevier/Stanford University).

H. K. Paliwal

Dr. H. K. Paliwal is an Professor in the Department of Mechanical Engineering, Institute of Engineering & Technology, Lucknow. He has served as the Director in Institute of Engineering & Technology, Lucknow.