CFD analysis on flow and performance parameters estimation of solar updraft tower (SUT) plant varying its geometrical configurations

ABSTRACT

A 3D numerical model is developed to estimate and analyze the flow and performance parameters of solar updraft tower (SUT) plant. The effects of geometrical parameters, such as chimney height and collector roof angle are studied. A turbulent, renormalization group (RNG) k-ε model and discrete ordinates (DO) model is used to solve the governing equations. It is concluded that with an increase in collector roof angle, air velocity increases but air temperature decreases. There is 31% velocity enhancement when the chimney height is increased from 3 to 8 m. The overall, chimney and collector efficiencies and power output are estimated to be 0.00354%, 0.0465%, 81.4% and 0.255 W, respectively.

KEYWORDS:

• CFD simulations
• collector roof angle
• Solar updraft tower
• turbulent flow
• parametric study

Nomenclature

a	=	Absorption coefficient, m−1
Acr	=	Collector roof angle, degree, °
Ch	=	Height of chimney, m
CFD	=	Computational fluid dynamics
Dap	=	Diameter of absorber plate, m
Dc	=	Chimney diameter, m
DO	=	Discrete ordinates
g	=	Gravity, ms−2
Gb	=	Turbulent kinetic energy due to buoyancy, m2s−2
Gk	=	Turbulent kinetic energy due to mean velocity, m2s−2
Gr	=	Grashof number
h	=	Convection heat transfer coefficient, Wm−2 K−1
I	=	Solar intensity, Wm−2
Ibλ	=	Black body intensity
k	=	Turbulent kinetic energy, m2s−2
L	=	characteristic length, m
n	=	Refractive index
Pr	=	Prandtl number
Ra	=	Rayleigh number
RNG	=	Renormalisation group
RTE	=	Radiative transfer equation
SUT	=	Solar updraft tower
t	=	Inlet gap, m
T	=	temperature, K

Greek symbol

α	=	Thermal diffusivity, m2s−1
β	=	Thermal expansion coefficient, °C−1
ε	=	Rate of dissipation of turbulent energy, m2s−3
μt	=	Turbulent viscosity, m2s−1
ϑ	=	Kinematic viscosity, m2s−1
ϕ	=	phase function, sr−1
dΩ´	=	solid angle, steradian
ρ	=	Density, kgm−3
σs	=	scattering coefficient

Acknowledgments

The authors acknowledge the financial support provided by Science & Engineering Research Board (SERB), Department of Science and Technology (DST), New Delhi - 110 070, India, Grant No. File Number: EEQ/2016/000111.

The authors wish to acknowledge the support received by way of proofreading from Dr. M.R. Vishwanathan, Assistant Professor of English, Humanities and Social Science Department, NIT Warangal, India.

Additional information

Funding

This work was supported by the Science & Engineering Research Board (SERB), Department of Science and Technology (DST), New Delhi - 110 070, India [File Number: EEQ/2016/000111];