Energy and exergy performances of natural circulation loop (NCL) with various water-based hybrid nanofluids (Al2O3 + TiO2, Al2O3 + CNT, Al2O3 + Ag, Al2O3 + Cu, Al2O3 + CuO, Al2O3 + graphene) with 1% volumetric concentration are compared in this study. New thermophysical property models have been proposed for hybrid nanofluids with different particle shapes and mixture ratio. Effects of power input, loop diameter, loop height, loop inclination and heater/cooler inclination on steady-state mass flow rate, effectiveness, and entropy generation are discussed as well. Results show that both the steady-state mass flow rate and energy–exergy performance are enhanced by using the hybrid nanofluids, except Al2O3 + graphene, which shows the performance decrement within the studied power range. Al2O3 + Ag hybrid nanofluid shows highest enhancement in mass flow rate of 4.8% compared to water. The shape of nanoparticle has shown a significant effect on steady-state performance; hybrid nanofluid having cylindrical and platelet shape nanoparticles yields lower mass flow rate than that of spherical shape. Mass flow rate increases with the increasing loop diameter and height, whereas decreases with the increasing loop and heater/cooler inclinations. Both effectiveness and entropy generation increase with the decreasing loop diameter and height, whereas increasing the loop and heater/cooler inclinations. This study reveals that the particle shape has a significant effect on the performance of hybrid nanofluids in NCL, and the use of hybrid nanofluid is more effective for higher power.

References

References
1.
Close
,
D. J.
,
1962
, “
The Performance of Solar Water Heaters With Natural Circulation
,”
Sol. Energy
,
6
(
1
), pp.
33
40
.
2.
Zvirin
,
Y.
,
Shitzer
,
A.
, and
Grossman
,
G.
,
1977
, “
The Natural Circulation Solar Heater-Models With Linear and Non-Linear Temperature Distribution
,”
Int. J. Heat Mass Transfer
,
20
(
9
), pp.
997
999
.
3.
Zvirin
,
Y.
,
Shitzer
,
A.
, and
Bartal-Bornstein
,
A.
,
1978
, “
On the Stability of the Natural Circulation Solar Heater
,”
Sixth International Heat Transfer Conference
, Toronto, ON, Canada, Aug. 7–11, pp.
141
145
.https://www.researchgate.net/publication/234317545_On_the_stability_of_the_natural_circulation_solar_heater
4.
Basu
,
D. N.
,
Bhattacharyya
,
S.
, and
Das
,
P. K.
,
2009
, “
Steady-State Behavior of a Two-Phase Natural Circulation Loop With Thermodynamic Nonequilibrium
,”
ASME J. Heat Transfer
,
131
(
2
), p.
022901
.
5.
Yadav
,
A. K.
,
Bhattacharyya
,
S.
, and
Ramgopal
,
M.
,
2016
, “
Optimum Operating Conditions for Subcritical/Supercritical Fluid-Based Natural Circulation Loops
,”
ASME J. Heat Transfer
,
138
(
11
), p.
112501
.
6.
Pastukhov
,
V. G.
, and
Maydanik
,
Y. F.
,
2007
, “
Low-Noise Cooling System for PC on the Base of Loop Heat Pipes
,”
Appl. Therm. Eng.
,
27
(
5–6
), pp.
894
901
.
7.
Zvirin
,
Y.
,
1982
, “
A Review of N. C. Loops in PWR and Other Systems
,”
Nucl. Eng. Des.
,
67
(
2
), pp.
203
225
.
8.
Huang
,
B. J.
, and
Zelaya
,
R.
,
1988
, “
Heat Transfer Behavior of a Rectangular Thermosyphon Loop
,”
ASME J. Heat Transfer
,
110
(
2
), pp.
487
493
.
9.
Sarkar
,
J.
,
Ghosh
,
P.
, and
Adil
,
A.
,
2015
, “
A Review on Hybrid Nanofluids: Recent Research, Development and Applications
,”
Renewable Sustainable Energy Rev.
,
43
, pp.
164
177
.
10.
Misale
,
M.
, and
Frogheri
,
M.
,
1999
, “
Influence of Pressure Drops on the Behaviour of a Single-Phase Natural Circulation Loop: Preliminary Results
,”
Int. Commun. Heat Mass Transfer
,
26
(
5
), pp.
597
606
.
11.
Vijayan
,
P. K.
,
Sharma
,
M.
, and
Saha
,
D.
,
2007
, “
Steady State and Stability Characteristics of Single-Phase Natural Circulation in a Rectangular Loop With Different Heater and Cooler Orientations
,”
Exp. Therm. Fluid Sci.
,
31
(
8
), pp.
925
945
.
12.
Garibaldi
,
P.
, and
Misale
,
M.
,
2008
, “
Experiments in Single-Phase Natural Circulation Mini Loops With Different Working Fluids and Geometries
,”
ASME J. Heat Transfer
,
130
(
10
), p. 104506.
13.
Sadhu
,
S.
,
Ramgopal
,
M.
, and
Bhattacharyya
,
S.
,
2018
, “
Steady-State Analysis of a High-Temperature Natural Circulation Loop Based on Water-Cooled Supercritical CO2
,”
ASME J. Heat Transfer
,
140
(
6
), p.
062502
.
14.
Misale
,
M.
,
Garibaldi
,
P.
,
Tarozzi
,
L.
, and
Barozzi
,
G. S.
,
2011
, “
Influence of Thermal Boundary Conditions on the Dynamic Behaviour of a Rectangular Single-Phase Natural Circulation Loop
,”
Int. J. Heat Fluid Flow
,
32
(
2
), pp.
413
423
.
15.
Misale
,
M.
,
2016
, ” “
Experimental Study on the Influence of Power Steps on the Thermohydraulic Behavior of a Natural Circulation Loop
,”
Int. J. Heat Mass Transfer
,
99
, pp.
782
791
.
16.
Cammi
,
A.
,
Misale
,
M.
,
Devia
,
F.
,
Cauzzi
,
M. T.
,
Pini
,
A.
, and
Luzzi
,
L.
,
2017
, “
Stability Analysis by Means of Information Entropy: Assessment of a Novel Method Against Natural Circulation Experimental Data
,”
Chem. Eng. Sci.
,
166
, pp.
220
234
.
17.
Nayak
,
A. K.
,
Gartia
,
M. R.
, and
Vijayan
,
P. K.
,
2008
, “
An Experimental Investigation of Single-Phase Natural Circulation Behaviour in a Rectangular Loop With Al2O3 Nanofluids
,”
Exp. Therm. Fluid Sci.
,
33
(
1
), pp.
184
189
.
18.
Nayak
,
A. K.
,
Gartia
,
M. R.
, and
Vijayan
,
P. K.
,
2009
, “
Nanofluids: A Novel Promising Flow Stabilizer in Natural Circulation Systems
,”
Am. Inst. Chem. Eng.
,
55
(
1
), pp.
268
274
.
19.
Nayak
,
A. K.
,
Gartia
,
M. R.
, and
Vijayan
,
P. K.
,
2009
, “
Thermal–Hydraulic Characteristics of a Single-Phase Natural Circulation Loop With Water and Al2O3 Nanofluid
,”
Nucl. Eng. Des.
,
239
(
3
), pp.
526
540
.
20.
Misale
,
M.
,
Devia
,
F.
, and
Garibaldi
,
P.
,
2012
, “
Experiments With Al2O3 Nanofluid in a Single-Phase Natural Circulation Mini-Loop: Preliminary Results
,”
Appl. Therm. Eng.
,
40
, pp.
64
70
.
21.
Ho
,
C. J.
,
Chung
,
Y. N.
, and
Lai
,
C. M.
,
2014
, “
Thermal Performance of Al2O3/Water Nanofluid in a Natural Circulation Loop With a Mini-Channel Heat Sink and Heat Source
,”
Energy Convers. Manage.
,
87
, pp.
848
858
.
22.
Doganay
,
S.
, and
Turgut
,
A.
,
2015
, “
Enhanced Effectiveness of Nanofluid Based Natural Circulation Mini Loop
,”
Appl. Therm. Eng.
,
75
, pp.
669
676
.
23.
Koca
,
H. D.
,
Doganay
,
S.
, and
Turgut
,
A.
,
2017
, “
Thermal Characteristics and Performance of Ag-Water Nanofluid: Application to Natural Circulation Loops
,”
Energy Convers. Manage.
,
135
, pp.
9
20
.
24.
Bejjam
,
R. B.
, and
Kumar
,
K. K.
,
2018
, “
Numerical Investigation to Study the Effect of Loop Inclination Angle on Thermal Performance of Nanofluid-Based Single-Phase Natural Circulation Loop
,”
Int. J. Ambient Energy
(epub).
25.
Bejjam
,
R. B.
, and
Kumar
,
K. K.
,
2017
, “
Numerical Study on Heat Transfer Characteristics of Nanofluid Based Natural Circulation Loop
,”
Therm. Sci.
,
22
(
2
), pp.
1
12
.
26.
Devi
,
P.
,
Rao
,
C. S.
, and
Kumar
,
K.
,
2018
, “
Suitability of Magnetic Nanofluid in Heat Transfer Loops
,”
Int. J. Heat Technol.
,
36
(
1
), pp.
195
200
.
27.
Thomas
,
S.
, and
Sobhan
,
C. B.
,
2018
, “
Stability and Transient Performance of Vertical Heater Vertical Cooler Natural Circulation Loops With Metal Oxide Nanoparticle Suspensions
,”
Heat Transfer Eng.
,
39
(
10
), pp.
861
873
.
28.
Vijayan
,
P. K.
,
2002
, “
Experimental Observations on the General Trends of the Steady State and Stability Behaviour of Single-Phase Natural Circulation Loops
,”
Nucl. Eng. Des.
,
215
(
1–2
), pp.
139
152
.
29.
Saha
,
R.
,
Sen
,
S.
,
Mookherjee
,
S.
,
Ghosh
,
K.
,
Mukhopadhyay
,
A.
, and
Sanyal
,
D.
,
2015
, “
Experimental and Numerical Investigation of a Single-Phase Square Natural Circulation Loop
,”
ASME J. Heat Transfer
,
137
(
12
), p.
121010
.
30.
Vijayan
,
P. K.
,
Sharma
,
M.
,
Pilkhwal
,
D. S.
,
Saha
,
D.
, and
Sinha
,
R. K.
,
2010
, “
A Comparative Study of Single-Phase, Two-Phase, and Supercritical Natural Circulation in a Rectangular Loop
,”
ASME J. Eng. Gas Turbines Power
,
132
(
10
), p.
102913
.
31.
Qiang
,
L.
, and
Yimin
,
X.
,
2002
, “
Convective Heat Transfer and Flow Characteristics of Cu-Water Nanofluid
,”
Sci. China Ser. E-Technol. Sci.
,
459
(
4
), pp.
409
416
.
32.
Ogut
,
E. B.
,
2009
, “
Natural Convection of Water-Based Nanofluids in an Inclined Enclosure With a Heat Source
,”
Int. J. Therm. Sci.
,
48
, pp.
2063
2073
.
33.
Devarajan
,
M.
,
Krishnamurthy
,
N. P.
,
Balasubramanian
,
M.
,
Ramani
,
B.
,
Wongwises
,
S.
,
El-Naby
,
K. A.
, and
Sathyamurthy
,
R.
,
2018
, “
Thermophysical Properties of CNT and CNT/Al2O3 Hybrid Nanofluid
,”
Micro Nano Lett.
,
13
(
5
), pp.
617
621
.
34.
Deng
,
L.
,
Young
,
R. J.
,
Kinloch
,
I. A.
,
Sun
,
R.
,
Zhang
,
G.
,
Noe
,
L.
, and
Monthioux
,
M.
,
2014
, “
Coefficient of Thermal Expansion of Carbon Nanotubes Measured by Raman Spectroscopy
,”
Appl. Phys. Lett.
,
104
, p.
051901
.
35.
Sundar
,
L. S.
,
Sharma
,
K. V.
,
Singh
,
M. K.
, and
Sousa
,
A. C. M.
,
2017
, “
Hybrid Nanofluids Preparation, Thermal Properties, Heat Transfer and Friction Factor—A Review
,”
Renewable Sustainable Energy Rev.
,
68
, pp.
185
198
.
36.
Chamkha
,
A. J.
,
Miroshnichenko
,
I. V.
, and
Sheremet
,
M. A.
,
2017
, “
Numerical Analysis of Unsteady Conjugate Natural Convection of Hybrid Water-Based Nanofluid in a Semi-Circular Cavity
,”
ASME J. Therm. Sci. Eng. Appl.
,
9
(4), p. 041004.
37.
Timofeeva
,
E. V.
,
Routbort
,
J. L.
, and
Singh
,
D.
,
2009
, “
Particle Shape Effects on Thermophysical Properties of Alumina Nanofluids
,”
J. Appl. Phys.
,
106
(
1
), p.
0143040
.
38.
Klein
,
S. A.
,
2017
, “
Engineering Equation Solver Professional, Version V10.215
,”
F-Chart Software
,
Madison, WI
.
39.
Vijayan
,
P. K.
,
Nayak
,
A. K.
,
Saha
,
D.
, and
Gartia
,
M. R.
,
2008
, “
Effect of Loop Diameter on the Steady State and Stability Behaviour of Single-Phase and Two-Phase Natural Circulation Loops
,”
Sci. Technol. Nucl. Install.
,
2008
, p.
672704
.
40.
Suresh
,
S.
,
Venkitaraj
,
K. P.
,
Selvakumar
,
P.
, and
Chandrasekar
,
M.
,
2011
, “
Synthesis of Al2O3–Cu/Water Hybrid Nanofluids Using Two Step Method and Its Thermo Physical Properties
,”
Colloids Surf. A
,
388
(
1–3
), pp.
41
48
.
41.
Tiwari
,
A. K.
,
Ghosh
,
P.
, and
Sarkar
,
J.
,
2015
, “
Particle Concentration Levels of Various Nanofluids in Plate Heat Exchanger for Best Performance
,”
Int. J. Heat Mass Transfer
,
89
, pp.
1110
1118
.
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