Abstract

A new three-zone heat extraction system and its analytical model for maximizing the thermal power output of salt gradient solar ponds against a given volume is proposed. The present study considers internal heat exchangers installed within the non-convective zone (NCZ), lower-convective zone (LCZ), and the ground below the pond. The work is validated against a simplified version of the model (eliminating ground and bottom-zone heat extractions) available in the existing literature. Contrary to the conventional practice of optimizing only the middle-zone pond thickness, here, the newly proposed expression is used to find ideal values of both the middle- and bottom-zone thicknesses of the pond along with its cross-sectional area. The present work acknowledges that although the three-zone heat extraction system is the best, yet if a choice for two-zone heat extraction is to be made between the NCZ–LCZ and ground–LCZ, then the former is a better alternative. The power output is observed to increase asymptotically with mass flow rates of the three heat exchangers. However, their values must lie much below their theoretical asymptotic limits and their selection is regulated by constructional and operational constraints. These involve a minimum pond depth to offset surface evaporation, ground seepage water loss, and constraints preventing turbulent flow in heat exchangers to reduce friction loss and pumping power. This work recommends using three heat exchangers instead of either one or two and provides cardinal guidelines to extract heat in an ideal manner for a fixed solar pond volume.

References

1.
Sukhatme
,
K.
, and
Sukhatme
,
S. P.
,
1996
,
Solar Energy: Principles of Thermal Collection and Storage
,
Tata McGraw-Hill Education
,
New Delhi
.
2.
Newell
,
T. A.
,
1983
, “
Simulation of a Solar Pond With a Stratified Storage Zone
,”
ASME J. Solar Energy Eng.
,
105
(
4
), pp.
363
368
.
3.
Lowrey
,
D. P.
, and
Johnson
,
R. R.
,
1986
, “
Simulation of a Solar Pond Using Upward Flow Through the Storage Zone
,”
ASME J. Solar Energy Eng.
,
108
(
4
), pp.
325
331
.
4.
Prasad
,
R.
, and
Rao
,
D. P.
,
1996
, “
Theoretical Performance of a Solar Pond With Enhanced Ground Energy Storage
,”
ASME J. Solar Energy Eng.
,
118
(
2
), pp.
101
106
.
5.
Arulanantham
,
M.
,
Avanti
,
P.
, and
Kaushika
,
N. D.
,
1997
, “
Solar Pond With Honeycomb Surface Insulation System
,”
Renew. Energy
,
12
(
4
), pp.
435
443
.
6.
Andrews
,
J.
, and
Akbarzadeh
,
A.
,
2005
, “
Enhancing the Thermal Efficiency of Solar Ponds by Extracting Heat From the Gradient Layer
,”
Solar Energy
,
78
(
6
), pp.
704
716
.
7.
Dah
,
M. M. O.
,
Ouni
,
M.
,
Guizani
,
A.
, and
Belghith
,
A.
,
2005
, “
Study of Temperature and Salinity Profiles Development of Solar Pond in Laboratory
,”
Desalination
,
183
, pp.
179
185
.
8.
Jaefarzadeh
,
M. R.
,
2006
, “
Heat Extraction From a Salinity-Gradient Solar Pond Using in Pond Heat Exchanger
,”
Appl. Therm. Eng.
,
26
(
16
), pp.
1858
1865
.
9.
Tundee
,
S.
,
Terdtoon
,
P.
,
Sakulchangsatjatai
,
P.
,
Singh
,
R.
, and
Akbarzadeh
,
A.
,
2010
, “
Heat Extraction from Salinity-Gradient Solar Ponds Using Heat Pipe Heat Exchangers
,”
Solar Energy
,
84
(
9
), pp.
1706
1716
.
10.
Date
,
A.
,
Yaakob
,
Y.
,
Date
,
A.
,
Krishnapillai
,
S.
, and
Akbarzadeh
,
A.
,
2013
, “
Heat Extraction From Non-Convective and Lower Convective Zones of the Solar Pond: A Transient Study
,”
Solar Energy
,
97
, pp.
517
528
.
11.
Alcaraz
,
A.
,
Valderrama
,
C.
,
Cortina
,
J. L.
,
Akbarzadeh
,
A.
, and
Farran
,
A.
,
2016
, “
Enhancing the Efficiency of Solar Pond Heat Extraction by Using Both Lateral and Bottom Heat Exchangers
,”
Solar Energy
,
134
, pp.
82
94
.
12.
Ganguly
,
S.
,
Date
,
A.
, and
Akbarzadeh
,
A.
,
2017
, “
Heat Recovery From Ground Below the Solar Pond
,”
Solar Energy
,
155
, pp.
1254
1260
.
13.
Ganguly
,
S.
,
Jain
,
R.
,
Date
,
A.
, and
Akbarzadeh
,
A.
,
2017
, “
On the Addition of Heat to Solar Pond From External Sources
,”
Solar Energy
,
144
, pp.
111
116
.
14.
Alcaraz
,
A.
,
Montalà
,
M.
,
Valderrama
,
C.
,
Cortina
,
J. L.
,
Akbarzadeh
,
A.
, and
Farran
,
A.
,
2018
, “
Increasing the Storage Capacity of a Solar Pond by Using Solar Thermal Collectors: Heat Extraction and Heat Supply Processes Using In-Pond Heat Exchangers
,”
Solar Energy
,
171
, pp.
112
121
.
15.
Mansouri
,
A. E.
,
Hasnaoui
,
M.
,
Amahmid
,
A.
, and
Dahani
,
Y.
,
2018
, “
Transient Theoretical Model for the Assessment of Three Heat Exchanger Designs in a Large-Scale Salt Gradient Solar Pond: Energy and Exergy Analysis
,”
Energy Conv. Manag.
,
167
, pp.
45
62
.
16.
Ganguly
,
S.
,
Date
,
A.
, and
Akbarzadeh
,
A.
,
2018
, “
Investigation of Thermal Performance of a Solar Pond With External Heat Addition
,”
ASME J. Solar Energy Eng.
,
140
(
2
), p.
24501
.
17.
Ganguly
,
S.
,
Date
,
A.
, and
Akbarzadeh
,
A.
,
2018
, “
Effectiveness of Bottom Insulation of a Salinity Gradient Solar Pond
,”
ASME J. Solar Energy Eng.
,
140
(
4
), p.
44502
.
18.
Wang
,
Y. F.
, and
Akbarzadeh
,
A.
,
1983
, “
A Parametric Study on Solar Ponds
,”
Solar Energy
,
30
(
6
), pp.
555
562
.
19.
Rabl
,
A.
, and
Nielsen
,
C. E.
,
1975
, “
Solar Ponds for Space Heating
,”
Solar Energy
,
17
(
1
), pp.
1
12
.
20.
Bryant
,
H. C.
, and
Colbeck
,
I.
,
1977
, “
A Solar Pond for London?
,”
Solar Energy
,
19
(
3
), pp.
321
322
.
You do not currently have access to this content.