Abstract

A geothermal heat exchanger (GHE) uses geothermal energy for heating or cooling residential places during winter or summer. Two different designs of GHEs, the straight pipe and coiled pipe designs, are evaluated in this study, and the effect of nanofluids as the working fluid is investigated. For this purpose, a mathematical model is developed, validated, and used to predict the temperature gain, heat gain, exergy gain, and pressure loss of the working fluid for different concentrations of additive ceramic nanoparticles of aluminum oxide (Al2O3) and magnesium oxide (MgO) in the working fluid. It is shown that the coiled pipe design has a better performance compared to the straight pipe design for GHEs. It is also shown how the temperature, heat gain, and exergy gain change with increasing the additive nanoparticles into the base fluid, which is water, while the pressure loss does not change significantly. The temperature gain increases about 60% when the volume fraction of nanoparticles in the base fluid reaches 2%. This also helps to improve the natural circulation of working fluid and the GHE may not need a circulating pump to run at low flowrates. It is also shown that the additive MgO nanoparticles are more effective than Al2O3 nanoparticles to improve the GHE performance.

References

1.
Wheeler
,
J.
,
2005
, “
Geodynamics by D. L. Turcotte and G. Schubert. Cambridge University Press, 2002. No. of Pages: 456. ISBN 0 521 66624 4 (Soft Covers). ISBN 0 521 66186 2 (Hardback)
,”
Geol. J.
,
40
(
2
), pp.
246
246
.
2.
William
,
E.
,
2010
,
Geothermal Energy: Renewable Energy and the Environment
,
CRC Press
,
Boca Raton, FL
.
3.
Biglarian
,
H.
,
Abbaspour
,
M.
, and
Saidi
,
M. H.
,
2017
, “
A Numerical Model for Transient Simulation of Borehole Heat Exchangers
,”
Renew. Energy
,
104
(
C
), pp.
224
237
.
4.
Cvetkovski
,
C. G.
,
2014
, “
Modelling of Flow and Heat Transport in Vertical Loop Ground Heat Exchangers
,” Master Thesis, https://scholar.uwindsor.ca/etd/5158/.
5.
Hope
,
W.
,
2013
, “
Numerical Analysis of Thermal Behavior and Fluid Flow in Geothermal Energy Piles
,” Master Thesis, https://vtechworks.lib.vt.edu/handle/10919/24013.
6.
Jakubský
,
M.
,
Lenhard
,
R.
,
Vantúch
,
M.
, and
Malcho
,
M.
,
2012
, “
Borehole Model for Simulation Transport Geothermal Heat With Heat Pipe System and With Forced Circulation of Heat Carrier
,”
EPJ Web Conference
,
Europe
,
April
, No. 25, p.
01030
.
7.
Mirzaei
,
M.
,
Saffar-Avval
,
M.
, and
Naderan
,
H.
,
2014
, “
Heat Transfer Investigation of Laminar Developing Flow of Nanofluids in a Microchannel Based on Eulerian–Lagrangian Approach
,”
Can. J. Chem. Eng.
,
92
(
6
), pp.
1139
1149
.
8.
Goutam
,
S.
, and
Paul
,
M. C.
,
2014
, “
Discrete Phase Approach for Nanofluids Flow in Pipe
,”
Second International Conference on Advances in Civil, Structural and Mechanical Engineering– CSM
,
Birmingham, UK
,
November
.
9.
Jin
,
K.
,
2011
, “
Modeling Nano-Particle Migration in Pipe Flow Through Eulerian–Lagrangian Approach
,” Master Thesis.
10.
Kumar
,
S.
,
Kothiyal
,
A. D.
,
Bisht
,
M. S.
, and
Kumar
,
A.
,
2017
, “
Numerical Analysis of Thermal Hydraulic Performance of Al2O3–H2O Nanofluid Flowing Through a Protrusion Obstacles Square Mini Channel
,”
Case Stud. Therm. Eng.
,
9
(
C
), pp.
108
121
.
11.
Drew
,
D. A.
, and
Passman
,
S. L.
,
1999
,
Theory of Multicomponent Fluids
,
Springer
.
12.
Kumar
,
S.
,
Kothiyal
,
A. D.
,
Bisht
,
M. S.
, and
Kumar
,
A.
,
2017
, “
Turbulent Heat Transfer and Nanofluid Flow in a Protruded Ribbed Square Passage
,”
Results Phys.
,
7
, pp.
3603
3618
.
13.
Ground Temperatures as a Function of Location, Season, and Depth
,
2015
, https://www.builditsolar.com/Projects/Cooling/EarthTemperatures.htm, Accessed January 3, 2020.
14.
Jones
,
W. P.
, and
Launder
,
B. E.
,
1972
, “
The Prediction of Laminarization With a Two-Equation Model of Turbulence
,”
Int. J. Heat Mass Transfer
,
15
(
2
), pp.
301
314
.
15.
Wilcox
,
D. C.
,
2008
, “
Formulation of the Kω Turbulence Model Revisited
,”
AIAA J.
,
46
(
11
), pp.
2823
2838
.
16.
Launder
,
B. E.
,
Reece
,
G. J.
, and
Rodi
,
W.
,
1975
, “
Progress in the Development of a Reynolds-Stress Turbulence Closure
,”
J. Fluid Mech.
,
68
(
3
), pp.
537
566
.
17.
Moeng
,
C.-H.
, and
Sullivan
,
P
,
2003
, “
Large Eddy Simulation
,”
Encyclopedia of Atmospheric Sciences
, pp.
1140
1150
.
18.
Holgate
,
J.
,
Skillen
,
A.
,
Craft
,
T.
, and
Revell
,
A.
,
2019
, “
A Review of Embedded Large Eddy Simulation for Internal Flows
,”
Arch. Comput. Methods Eng.
,
26
(
4
), pp.
865
882
.
19.
Zhou
,
L.
,
2018
,
Theory and Modeling of Dispersed Multiphase Turbulent Reacting Flows
,
Butterworth-Heinemann
,
Oxford
.
20.
Maı¨ga
,
S. E. B.
,
Nguyen
,
C. T.
,
Galanis
,
N.
, and
Roy
,
G.
,
2004
, “
Heat Transfer Behaviours of Nanofluids in a Uniformly Heated Tube
,”
Superlattices Microstruct.
,
35
(
3–6
), pp.
543
557
.
21.
Kole
,
M.
, and
Dey
,
T. K.
,
2010
, “
Thermal Conductivity and Viscosity of Al2O3 Nanofluid Based on Car Engine Coolant
,”
J. Phys. D Appl. Phys.
,
43
(
31
), p.
315501
.
22.
Davarnejad
,
R.
, and
Jamshidzadeh
,
M.
,
2015
, “
CFD Modeling of Heat Transfer Performance of MgO–Water Nanofluid Under Turbulent Flow
,”
Eng. Sci. Technol.
,
18
(
4
), pp.
536
542
.
23.
Farhad
,
S.
,
Younessi-Sinaki
,
M.
,
Golriz
,
M. R.
, and
Hamdullahpur
,
F.
,
2008
, “
Exergy Analysis and Performance Evaluation of CNG to LNG Converting Process
,”
Int. J. Exergy
,
5
(
2
), pp.
164
176
.
24.
Farhad
,
S.
,
Saffar-Avval
,
M.
, and
Younessi-Sinaki
,
M.
,
2008
, “
Efficient Design of Feedwater Heaters Network in Steam Power Plants Using Pinch Technology and Exergy Analysis
,”
Int. J. Energy Res.
,
32
(
1
), pp.
1
11
.
25.
Classification of Flows, Laminar and Turbulent Flows
,
2005
, http://www-mdp.eng.cam.ac.uk/web/library/enginfo/aerothermal_dvd_only/aero/fprops/pipeflow/node8.html, Accessed September 25, 2020.
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