Vol.:(0123456789) 1 3
Journal of Thermal Analysis and Calorimetry
https://doi.org/10.1007/s10973-021-10705-6
Assessment of alumina/water nanofuid in a glazed tube and sheet
photovoltaic/thermal system with geothermal cooling
Sanjeev Jakhar
1
· Mukul Kant Paliwal
1
· Nilesh Purohit
2
Received: 1 November 2020 / Accepted: 21 February 2021
© Akadémiai Kiadó, Budapest, Hungary 2021
Abstract
This article presents evaluation of alumina/water nanofuid (NF) in a glazed tube and sheet photovoltaic/thermal (PV/T)
system with ground-coupled heat exchanger (GCHE) in semi-arid region of Pilani, Rajasthan (India). Conventionally in the
literature, the cooling performance of NF is reported compared to the normal fuid cooling under equal Reynolds number
(Re) comparison criterion. However, according to many researchers, equal pumping power-based evaluation is more prag-
matic and is explored here. The frst law of thermodynamics analysis is invoked to appropriately assess the replacement of
water with NF in the PV/T system coupled with GCHE. Nanoparticle concentration is varied from 0.5% to 6% by volume
fraction and the Re from 3000 to 9000. Temperature of PV panel, temperature diference in PV/T outlet and inlet, electrical
efciency, thermal efciency and Bejan number in PV as well as in GCHE are computed using a validated mathematical
model for both equal Re and equal pumping power evaluation criteria. The performance of PV/T system with NF is found
superior under equal Re comparison. The improvement observed are reduction in PV panel temperature by 2 °C, reduction in
temperature diference in PV/T outlet and inlet by 6 °C, rise in electrical efciency by 0.1% and a rise in thermal efciency
by 4%. However, the performance of PV/T system with NF is found inferior under equal pumping power evaluation criterion.
Keywords Solar energy · Photovoltaic/thermal (PV/T) · Ground-coupled heat exchanger (GCHE) · Alumina nanofuid ·
Pumping power · Electrical and thermal efciency
Abbreviations
a
f
Equivalent diameter of base fuid molecule (m)
a
p
Nanoparticle diameter (m)
A
c
Area of PV/T (m
2
)
B Width of absorber plate (m)
Be Bejan number
C Specifc heat (J·kg
−1
K
−1
)
C
B
Boltzmann’s constant [1.38066·10
−23
J·K
−1
]
C
w
Specifc heat of water (J/kg K)
D
out
Outer diameter of PV/T system tubes
D
in
Inner diameter of PV/T system tubes
dx Element length of fow pipe (m)
F
PV/T collector efciency factor
F
R
Flow rate factor
f Friction factor for smooth pipes
G(I ) Global solar radiation (W m
−2
)
h Convection heat transfer coefcient (W m
−2
K
−1
)
k Thermal conductivity (W m
−1
K
−1
)
k
s
Thermal conductivity of soil (W m
−1
K
−1
)
l Length (m)
m Mass fow rate of fuid (kg s
−1
)
N Avogadro number (6.022 × 10
23
mol
−1
)
NF Nanofuid
NP Nanoparticle
Nu Nusselt number
PF
1
Penalty factor owing the glass cover of PV Panel
PF
2
Penalty factor owing the absorber plate below the
PV panel
Pr Prandtl number
PP Pumping power (m·W)
Re Reynolds number
r
s
Radius of soil annulus (m)
r
o
Outer radius of GCHE pipe (m)
S Entropy generation (W·K
−1
)
SCs Solar cell
T Temperature (K)
t Thickness (m)
* Sanjeev Jakhar
sanjeevj450@gmail.com
1
Department of Mechanical Engineering, Mody University
of Science and Technology, Lakshmangarh, Sikar,
Rajasthan 332311, India
2
Mechanical Engineering Department, Birla Institute
of Technology and Science Pilani, Pilani, Rajasthan 333031,
India