Abstract

Several artificial roughness (ribs) configurations have been used in flat plate solar air heaters (SAH) in recent years to improve their overall performance. In the present work, energy and exergy analyses of rectangular ribs in a triangular duct SAH for varying relative rib heights (e/D = 0.02–0.04), relative rib pitches (P/e = 5–15), and rib aspect ratios (e/w = 0.5–4) are evaluated and compared with smooth SAH. The analysis reveals that the entropy generated due to heat transfer is lower for the ribbed triangular duct compared to the smooth duct. It is also observed that the width of the rib plays a crucial role in minimizing heat losses to the environment. A maximum reduction of 43% and 62% in exergy losses to the environment and exergy losses due to heat transfer to the fluid is achieved, respectively, with a rib aspect ratio (e/w) of 4 compared to the smooth plate. It is found that in contrast to the smooth plate, ribs beneath the absorber plate effectively improves thermal and exergetic efficiency. Maximum enhancement of 36% and 17% is obtained in exergetic efficiency (ηex) and thermal efficiency (ηth), respectively, for e/w = 4, P/e = 10 and e/D = 0.04. Results also show the superiority of the ribbed triangular duct over the ribbed rectangular duct for an application requiring compact SAH with a higher flowrate.

References

References
1.
Khan
,
M. M. A.
,
Ibrahim
,
N. I.
,
Mahbubul
,
I. M.
,
Ali
,
H. M.
,
Saidur
,
R.
, and
Al-Sulaiman
,
F. A.
,
2018
, “
Evaluation of Solar Collector Designs With Integrated Latent Heat Thermal Energy Storage: A Review
,”
Sol. Energy
,
166
, pp.
334
350
. 10.1016/j.solener.2018.03.014
2.
Baig
,
W.
, and
Ali
,
H. M.
,
2019
, “
An Experimental Investigation of Performance of a Double Pass Solar Air Heater With Foam Aluminium Thermal Storage Medium
,”
Case Stud. Therm. Eng.
,
14
, p.
100440
. 10.1016/j.csite.2019.100440
3.
Sajawal
,
M.
,
Rehman
,
T. U.
,
Ali
,
H. M.
,
Sajjad
,
U.
,
Raza
,
A.
, and
Bhatti
,
M. S.
,
2019
, “
Experimental Thermal Performance Analysis of Finned Tube-Phase Change Material Based Double Pass Solar Air Heater
,”
Case Stud. Therm. Eng.
,
15
, p.
100543
. 10.1016/j.csite.2019.100543
4.
Prasad
,
B. N.
, and
Saini
,
J. S.
,
1988
, “
Effect of Artificial Roughness on Heat Transfer and Friction Factor in a Solar Air Heater
,”
Sol. Energy
,
41
(
6
), pp.
555
560
. 10.1016/0038-092X(88)90058-8
5.
Gupta
,
D.
,
Solanki
,
S. C.
, and
Saini
,
J. S.
,
1993
, “
Heat and Fluid Flow in Rectangular Solar Air Heater Ducts Having Transverse rib Roughness on Absorber Plates
,”
Sol. Energy
,
51
(
1
), pp.
31
37
. 10.1016/0038-092X(93)90039-Q
6.
Momin
,
A. M. E.
,
Saini
,
J. S.
, and
Solanki
,
S. C.
,
2002
, “
Heat Transfer and Friction in Solar Air Heater Duct With V-Shaped rib Roughness on Absorber Plate
,”
Int. J. Heat Mass Transfer
,
45
(
16
), pp.
3383
3396
. 10.1016/S0017-9310(02)00046-7
7.
Chaube
,
A.
,
Sahoo
,
P. K.
, and
Solanki
,
S. C.
,
2006
, “
Analysis of Heat Transfer Augmentation and Flow Characteristics Due to Rib Roughness Over Absorber Plate of a Solar air Heater
,”
Renewable Energy
,
31
(
3
), pp.
317
331
. 10.1016/j.renene.2005.01.012
8.
Tanda
,
G.
,
2011
, “
Performance of Solar Air Heater Ducts With Different Types of Ribs on the Absorber Plate
,”
Energy
,
36
(
11
), pp.
6651
6660
. 10.1016/j.energy.2011.08.043
9.
Patel
,
S. S.
, and
Lanjewar
,
A.
,
2019
, “
Heat Transfer and Friction Factor Correlations for Solar Air Heater with Gap in V-rib with Symmetrical Gap and Staggered Ribs
,”
ASME J. Therm. Sci. Eng. Appl.
,
12
(
3
), p.
031018
. 10.1115/1.4045251
10.
Braga
,
S. L.
, and
Saboya
,
F. E. M.
,
1996
, “
Turbulent Heat Transfer and Pressure Drop in an Internally Finned Equilateral Triangular Duct
,”
Exp. Therm. Fluid Sci.
,
12
(
1
), pp.
57
64
. 10.1016/0894-1777(95)00069-0
11.
Rang
,
H. J.
,
Wong
,
T. T.
, and
Leung
,
C. W.
,
1998
, “
Effects of Surface Roughness on Forced Convection and Friction in Triangular Ducts
,”
Exp. Heat Transfer
,
11
(
3
), pp.
241
253
. 10.1080/08916159808946564
12.
Leung
,
C. W.
,
Wong
,
T. T.
, and
Probert
,
S. D.
,
2001
, “
Enhanced Forced-Convection From Ribbed or Machine-Roughened Inner Surfaces Within Triangular Ducts
,”
Appl. Energy
,
69
(
2
), pp.
87
99
. 10.1016/S0306-2619(01)00002-2
13.
Luo
,
D. D.
,
Leung
,
C. W.
, and
Chan
,
T. L.
,
2004
, “
Forced Convection and Flow Friction Characteristics of Air-Cooled Horizontal Equilateral Triangular Ducts With Ribbed Internal Surfaces
,”
Int. J. Heat Mass Transfer
,
47
(
25
), pp.
5439
5450
. 10.1016/j.ijheatmasstransfer.2004.07.003
14.
Singh
,
S.
,
2018
, “
Thermal Performance Analysis of Semi-Circular and Triangular Cross-Sectioned Duct Solar Air Heaters Under External Recycle
,”
J. Energy Storage
,
20
, pp.
316
336
. 10.1016/j.est.2018.10.003
15.
Kumar
,
R.
,
Kumar
,
A.
, and
Goel
,
V.
,
2017
, “
A Parametric Analysis of Rectangular rib Roughened Triangular Duct Solar air Heater Using Computational Fluid Dynamics
,”
Sol. Energy
,
157
, pp.
1095
1107
. 10.1016/j.solener.2017.08.071
16.
Kumar
,
R.
,
Goel
,
V.
, and
Kumar
,
A.
,
2018
, “
Investigation of Heat Transfer Augmentation and Friction Factor in Triangular Duct Solar air Heater Due to Forward Facing Chamfered Rectangular Ribs: A CFD Based Analysis
,”
Renewable Energy
,
115
, pp.
824
835
. 10.1016/j.renene.2017.09.010
17.
Kumar
,
R.
,
Goel
,
V.
,
Singh
,
P.
,
Saxena
,
A.
,
Kashyap
,
A. S.
, and
Rai
,
A.
,
2019
, “
Performance Evaluation and Optimization of Solar Assisted Air Heater With Discrete Multiple Arc Shaped Ribs
,”
J. Energy Storage
,
26
, p.
100978
. 10.1016/j.est.2019.100978
18.
Kumar
,
R.
, and
Kumar
,
A.
,
2017
, “
Experimental and Computational Fluid Dynamics Study on Fluid Flow and Heat Transfer in Triangular Passage Solar Air Heater of Different Configurations
,”
ASME J. Sol. Energy Eng.
,
139
(
4
), p.
041013
. 10.1115/1.4036775
19.
Jain
,
S. K.
,
Agrawal
,
G. D.
,
Misra
,
R.
,
Verma
,
P.
,
Rathore
,
S.
, and
Jamuwa
,
D. K.
,
2019
, “
Performance Investigation of a Triangular Solar Air Heater Duct Having Broken Inclined Roughness Using Computational Fluid Dynamics
,”
ASME J. Sol. Energy Eng.
,
141
(
6
), p.
061008
. 10.1115/1.4043751
20.
Jain
,
S. K.
,
Agrawal
,
G. D.
, and
Misra
,
R.
,
2020
, “
Experimental Investigation of Thermohydraulic Performance of the Solar Air Heater Having Arc-Shaped Ribs With Multiple Gaps
,”
ASME J. Therm. Sci. Eng. Appl.
,
12
(
1
), p.
011014
.
21.
Ratts
,
E. B.
, and
Raut
,
A. G.
,
2004
, “
Entropy Generation Minimization of Fully Developed Internal Flow With Constant Heat Flux
,”
ASME J. Heat Transfer
,
126
(
4
), pp.
656
659
. 10.1115/1.1777585
22.
Taufiq
,
B. N.
,
Masjuki
,
H. H.
,
Mahlia
,
T. M. I.
,
Saidur
,
R.
,
Faizul
,
M. S.
, and
Mohamad
,
E. N.
,
2007
, “
Second Law Analysis for Optimal Thermal Design of Radial fin Geometry by Convection
,”
Appl. Therm. Eng.
,
27
(
8–9
), pp.
1363
1370
. 10.1016/j.applthermaleng.2006.10.024
23.
Torres-Reyes
,
E.
,
Cervantes-de Gortari
,
J. G.
,
Ibarra-Salazar
,
B. A.
, and
Picon-Nunez
,
M.
,
2001
, “
A Design Method of Flat-Plate Solar Collectors Based on Minimum Entropy Generation
,”
Exergy Int. J.
,
1
(
1
), pp.
46
52
. 10.1016/S1164-0235(01)00009-7
24.
Layek
,
A.
,
Saini
,
J. S.
, and
Solanki
,
S. C.
,
2007
, “
Second Law Optimization of a Solar Air Heater Having Chamfered Rib–Groove Roughness on Absorber Plate
,”
Renewable Energy
,
32
(
12
), pp.
1967
1980
. 10.1016/j.renene.2006.11.005
25.
Gupta
,
M. K.
, and
Kaushik
,
S. C.
,
2009
, “
Performance Evaluation of Solar air Heater for Various Artificial Roughness Geometries Based on Energy, Effective and Exergy Efficiencies
,”
Renewable Energy
,
34
(
3
), pp.
465
476
. 10.1016/j.renene.2008.06.001
26.
Akpinar
,
E. K.
, and
Koçyiğit
,
F.
,
2010
, “
Energy and Exergy Analysis of a new Flat-Plate Solar air Heater Having Different Obstacles on Absorber Plates
,”
Appl. Energy
,
87
(
11
), pp.
3438
3450
. 10.1016/j.apenergy.2010.05.017
27.
Singh
,
S.
,
Chander
,
S.
, and
Saini
,
J. S.
,
2012
, “
Exergy Based Analysis of Solar air Heater Having Discrete V-Down rib Roughness on Absorber Plate
,”
Energy
,
37
(
1
), pp.
749
758
. 10.1016/j.energy.2011.09.040
28.
Sahu
,
M. K.
, and
Prasad
,
R. K.
,
2016
, “
Exergy Based Performance Evaluation of Solar Air Heater With Arc-Shaped Wire Roughened Absorber Plate
,”
Renewable Energy
,
96
, pp.
233
243
. 10.1016/j.renene.2016.04.083
29.
Howell
,
J. R.
, and
Bannerot
,
R. B.
,
1977
, “
Optimum Solar Collector Operation for Maximizing Cycle Work Output
,”
Sol. Energy
,
19
(
2
), pp.
149
153
. 10.1016/0038-092X(77)90052-4
30.
Kar
,
A. K.
,
1985
, “
Exergy Efficiency and Optimum Operation of Solar Collectors
,”
Appl. Energy
,
21
(
4
), pp.
301
314
. 10.1016/0306-2619(85)90014-5
31.
Luminosu
,
I.
, and
Fara
,
L.
,
2005
, “
Determination of the Optimal Operation Mode of a Flat Solar Collector by Exergetic Analysis and Numerical Simulation
,”
Energy
,
30
(
5
), pp.
731
747
. 10.1016/j.energy.2004.04.061
32.
Rosen
,
M. A.
, and
Dincer
,
I.
,
2004
, “
A Study of Industrial Steam Process Heating Through Exergy Analysis
,”
Int. J. Energy Res.
,
28
(
10
), pp.
917
930
. 10.1002/er.1005
33.
Kanoglu
,
M.
,
Dincer
,
I.
, and
Rosen
,
M. A.
,
2007
, “
Understanding Energy and Exergy Efficiencies for Improved Energy Management in Power Plants
,”
Energy Policy
,
35
(
7
), pp.
3967
3978
. 10.1016/j.enpol.2007.01.015
34.
Bliss
,
R. W.
, Jr
,
1959
, “
The Derivations of Several “Plate-Efficiency Factors” Useful in the Design of Flat-Plate Solar Heat Collectors
,”
Sol. Energy
,
3
(
4
), pp.
55
64
. 10.1016/0038-092X(59)90006-4
35.
Altfeld
,
K.
,
Leiner
,
W.
, and
Fiebig
,
M.
,
1988
, “
Second Law Optimization of Flat-Plate Solar Air Heaters Part I: The Concept of net Exergy Flow and the Modeling of Solar Air Heaters
,”
Sol. Energy
,
41
(
2
), pp.
127
132
. 10.1016/0038-092X(88)90128-4
36.
Akhtar
,
N.
, and
Mullick
,
S. C.
,
1999
, “
Approximate Method for Computation of Glass Cover Temperature and Top Heat-Loss Coefficient of Solar Collectors With Single Glazing
,”
Sol. Energy
,
66
(
5
), pp.
349
354
. 10.1016/S0038-092X(99)00032-8
37.
Bhagoria
,
J. L.
,
Saini
,
J. S.
, and
Solanki
,
S. C.
,
2002
, “
Heat Transfer Coefficient and Friction Factor Correlations for Rectangular Solar Air Heater Duct Having Transverse Wedge Shaped rib Roughness on the Absorber Plate
,”
Renewable Energy
,
25
(
3
), pp.
341
369
. 10.1016/S0960-1481(01)00057-X
38.
Saini
,
R. P.
, and
Saini
,
J. S.
,
1997
, “
Heat Transfer and Friction Factor Correlations for Artificially Roughened Ducts With Expanded Metal Mesh as Roughness Element
,”
Int. J. Heat Mass Transfer
,
40
(
4
), pp.
973
986
. 10.1016/0017-9310(96)00019-1
39.
Jaurker
,
A. R.
,
Saini
,
J. S.
, and
Gandhi
,
B. K.
,
2006
, “
Heat Transfer and Friction Characteristics of Rectangular Solar Air Heater Duct Using Rib-Grooved Artificial Roughness
,”
Sol. Energy
,
80
(
8
), pp.
895
907
. 10.1016/j.solener.2005.08.006
You do not currently have access to this content.