solar energy utilization

1. Under the Guidance of:
Dr. LALJEE PRASAD
Department of Mechanical Engg.
NIT, Jamshedpur
Presented by:
VIKASH KUMAR
2015RSME004
Department of Mechanical Engg.
NIT, Jamshedpur

2. CONTENTS
 Course Work Details
 Introduction
 Literature review
 Research gap
 Experimentation And Methodology
 Objectives
 References

3. COURSE WORK SUBJECTS
 (MEG7111) THERMODYNAMICS (completed)
 (MEG7112) ENERGY CONVERSION SYSTEM (completed)
 (MEG7123) SOLAR THERMAL ENERGY SYSTEM (completed)
 (MEG7131) NON CONVENTIONAL ENERGY SYSTEMS(completed)

4. RESULT
S. No. Course Code SUBJECT STATUS GRADE CREDIT
1 MEG 7111 THERMODYNA-
MICS
Completed A 4
2 MEG 7112 ENERGY
CONVERSION
SYSTEM
Completed B 4
3 MEG7123 SOLAR
THERMAL
SYSTEMS
Completed A 4
4 MEG7131 NON
CONVENTIONA
L ENERGY
SYSTEMS
Completed A 4

5. INTRODUCTION
 Solar air heaters (SAHs) form the foremost component of solar energy
utilization system. These air heaters absorb the incident solar radiation
and convert it into thermal energy at the absorbing surface and then
transfer this energy to a fluid flowing through the collector.
 SAHs are inexpensive and most used collection devices because of their
inherent simplicity.
 Enhancement of heat transfer in the solar air heater ducts can be
achieved by several means like using baffles, fins, ribs, dimples,groves
etc.
 It has many advantages like low fabrication, installation, and operational
costs, and can be constructed by using cheaper and lesser amount of
material.
 However, its efficiency is poor. The lower efficiency of solar air heater is
attributed to poor heat transfer characteristics of air, and also the air
cannot be used as storage fluid due to low thermal capacity.

6. The low efficiency of the SAH can be improved either by increasing
the surface area of the absorber plate or by using certain artificial
geometries on the absorber plate with some adverse effect of more
pumping power required due to increase in frictional loss in ducts
which is needed to be taken care of by using proper, geometrical
parameters and flow conditions.
The researcher always try to optimize the roughness which provide
high heat transfer at low pressure drop penalty.
Sub laminar layer is developed over absorber plate which acts as
thermal resistant to flowing air.
These roughness elements breaks up the boundary layers (also
known as laminar sub-layer)and induces greater turbulency which
results in heat transfer enhancement
This area of research has large opportunity for doing novel work to
achieve the heat transfer enhancement with new geometry with
different parameters.

7. Absorber plate :-
 A typical flat-plate collector is a metal box with a glass on top
and a dark coloured absorber plate on the bottom. The bottom
of the collector are usually insulated to minimize the heat
losses.
 Absorber plates are made of metal like copper, aluminium, GI
sheets and steel because they are good conductor of heat .
 A glass cover around the absorber plate helps in reducing the
convective and radiative losses to the surrounding.

9. LITERATURE REVIEW…..

10. Author
and
Year
Type of
System Used
Nature of
work
Outcomes
Liu et al(1984)
SAHs with the absorber
plate roughened by
extended surfaces
Experimental
Found that the pressure drops rapidly when
compared to heat transfer if the height of the
roughened element is extended beyond the laminar
sub layer
Prasad and
Saini (1988)
Fully developed
turbulent flow in a solar
air heater duct
Analytical
Convective heat transfer coefficient between
absorber plate and air in a flat-plate solar air
heater can be enhanced by providing the absorber
plate with artificial roughness
Prasad and
Mullick (1983)
SAHs with protruding
wires in underside of the
absorber plate
Experimental and
Analytical
Found improvement of 9% (from 63% to 72%) in
plate efficiency for Reynolds number of 40,000.

11. Author
and
Year
Type of
System Used
Nature of
work
Outcomes
Gupta et
al(1993)
Effect of transverse wire
roughness on absorber
plate on heat and fluid
flow characteristics in
fully developed
turbulent flow
Experimental
Concluded that the heat transfer increased up to
1.8 times than that of smooth solar air heaters at
α=60˚ and friction factor increases by 2.7 at α=70˚
for the range of parameters investigated
Saini and Saini
(1995)
Fully developed
turbulent flow with
expanded metal
mesh as artificial
roughness element.
Experimental
and analytical
It was found that that the maximum values of
Nusselt number and friction factor occurs at an
angle of attack of 61.9˚ and 72˚. Saini and Saini also
developed the correlation for Nusselt number and
friction factor
Ahn (2001)
Investigated on five
different types of
roughness element in
rectangular duct with
e/D 0.0476,
Experimental and
Analytical
Concluded that the triangular rib has the highest
heat transfer capacity and Nusselt number is higher
in the case of square and triangular ribs when
compared to semicircular ribs. The square ribs have
the highest friction factor

12. Author
and
Year
Type of
System Used
Nature of
work
Outcomes
Chandra et
al.(2003)
Investigated the effect
with varying number of
transverse ribbed walls
with the parameters
Re 10,000–80,000; P/e 8
and e/D 0.0625
Experimental
The maximum increase in the friction factor was
found to be 9.50 with four sided ribbed wall in
comparison with
one ribbed wall of 3.14.
Tanda (2004)
Investigated for heat
transfer coefficient and
friction factor in the
rectangular channel
with
Transverse continuous,
transverse broken and V-
shaped broken ribs
Experimental
Maximum performance of continuous transverse
ribs of 45˚ V-shaped ribs and
60˚ V-shaped ribs at the optimum value of P/e 13.3,
transverse broken ribs with P/e 4 and 8 give the
higher heat transfer augmentation.
Behura et al
(2016)
Novel type of three sides
artificially roughened
and glass covered solar
air heater under fully
developed turbulent flow
conditions.
Experimental and
Analytical
The value of Nusselt number in three sides
artificially roughened solar air heater enhances by
21–78% over one side roughened ones for the range
of parameters investigated. However, the friction
factor increases in the range of 2–38%

13. Author and Year Type of System Used Nature of work Outcomes
Kumar et
al.(2017)
Investigated the effect with V-
pattern dimpled obstacles solar
air passage for a Re range of 5000-
17000, Wc/Wd of 1-6, p/e of 9,
e/Dh of 0.037 and α of 55˚
Experimental
Developed Correlation for Nusselts number and friction
factor .
Gilani (2017)
Performance enhancement of
free convective solar air heater by
pin protrusions on the absorber
Experimental
Pin pitch of 16 mm increased the Nusselts number
the most. The efficiency was increased by 26.5% for
absorber plate with 16 mm pin pitch as compared to flat
smooth plate. The pin height of 4 mm proved to be the best
in enhancing the Nusselts number. A correlation was
developed to predict the Nusselts number for conical pin
protruded plates of dimensional ranges (16 mm < pin pitch
< 48 mm) and (2 mm < pin height < 4 mm) under free
convective flow for staggered arrangement.
Leontiev et al
(2017)
Experimental investigation of
heat transfer and drag on surfaces
coated with dimples of different
shape for the range of Re 20000-
70000. The dimples of six
different shapes were considered,
namely, spherical, oval,
teardrop dimples, spherical
dimples with rounded edges,
turned teardrop dimples, and
dimples obtained by milling a
sphere along a circular arc.
Experimental
The Reynolds number effect on the heat transfer
enhancement, the drag increase, and the heat-hydraulic
efficiency is determined. The average values of the above-
mentioned parameters are presented for all the surfaces
considered.

19. Present Work
dimple shape roughened absorber plate

20. Research gap
 Analytical results are available in plenty for heat transfer and friction factor
for one sides artificially roughened solar air heaters.
 Provision of artificial roughness of various geometries and orientations on
the absorber plate in solar air heaters have remained limited to only one side
(top side) of the solar air heater duct which results in higher values of heat
transfer and associated pressure drop.
 Researchers have proved that increasing the number of roughened surface
results in the increase of heat transfer and friction factor.
 By providing roughness to three sides (one bottom and two sides) of the
absorber plate may yield better results than the conventional SAHs.
 Plenty of work has been done by providing roughness to the single side of
the absorber plate which resulted in an appreciable increase in heat transfer
and friction factor.
 The present work is an effort towards seizing the opportunity that may exist
in any furthermost increase in heat transfer and friction factor by providing
the roughness on three walls of the absorber plate

21. Objectives of Present Work:
With a view that artificial roughness and glass covers, if provided on three sides i.e.
top and sides of the solar air heater duct, could perform even better than those of the
existing one side roughened and glass covered solar air heater. The present work has
been taken up with the following objectives:
1. To develop and calibrate the experimental set-up.
2. To perform experiments under actual outdoor conditions and to obtain data on such
collectors on one side as well as three sides roughened collector
3. To develop correlations for heat transfer and friction factor in three sides concave
dimple shape roughened solar air heater.
4. To see the effect of various parameters on heat transfer, friction factor and thermal
Performance vis-à-vis to compare the values with those of one side roughened and
three sides roughened solar air heater
5. To obtain the thermal and thermohydraulic performance for both one side and three
sides roughened solar air heater and observe the difference.

22. Work Done Till Date
 Design and development of solar air heater ducts-
Completed.
 Experimentation - Completed
 Data Analysis- Completed
 Research papers and thesis writing- In progress

23. Data Collected From Experimentation :
 Pressure difference across orifice meter
 Pressure drop across the duct
 Temperature of the absorber plate
 Temperature of the air in the duct
 Ambient temperature
 Intensity of solar radiation

24. Parameters To Be Evaluated:
 Reynolds number(Re)
 Useful Heat Gain(Qu)
 Convective Heat Transfer Coefficient(h)
 Nusselts Number(Nu)
 Friction Factor(f)
 Correlations for ‘Nu and f’ in three sides concave
dimple shape roughened solar air heater
 Thermal and Thermohydraulic performance
 Collector performance parameters (Plate efficiency
factor, collector heat removal factor)

25. References
•B. N. Prasad and J. S. Saini, 1988. Effect of artificial roughness on heat transfer
and friction factor in a solar air heater, Solar Energy 41 (555-560).
•Solar Engineering of Thermal Processes Fourth Edition by John A. Duffie
(Deceased), Emeritus Professor of Chemical Engineering and William A.
Beckman, Emeritus Professor of Mechanical Engineering
• S.K. Verma, B.N. Prasad, 2000. Investigation for the optimal thermo hydraulic
performance of artificial roughness solar air heaters. Renewable Energy 20 (19-
36).
• B. N. Prasad and J. S. Saini, 2000. Investigation for the optimal thermo
hydraulic performance of artificially roughened solar air heaters. Renewable
Energy 20 (19-36).
•Rajendra Karwa, S.C. Solanki, J.S. Saini, 2001. Thermo-hydraulic performance
of solar air heaters having integral chamfered rib roughness on absorber plates.
•J.L. Bhagoria , J.S. Saini, S.C. Solanki, 2002. Heat transfer coefficient and
friction facto correlations for rectangular solar air heater duct having transverse
wedge shaped rib roughness of the absorber plate.Renewable Energy 25 (341–
369).

26. • Liu Ye-Di, Diaz LA, Suryanarayana NV. Heat transfer enhancement in
airheating fiat-plate solar collectors. Trans ASME J Sol Energy Eng
1984;106:358–63.
• Prasad K, Mullick SC. Heat transfer characteristics of a solar air heater used
for drying purposes. Appl Energy 1983;13:83–93.
• Gupta D, Solanki SC, Saini JS. Heat and fluid flow in rectangular solar air
heater ducts having transverse rib roughness on absorber plates. Sol Energy
1993;51:31–37.
• Saini RP, Saini JS. Heat transfer and friction factor correlations for artificially
roughened ducts with expanded metal mesh as roughness element. Int J Heat
Mass Transf 1995;40:973–86.
• M. Sethi, Thakur N.S. Varun, Correlations for solar air heater duct with
dimpled shape roughness elements on absorber plate, Sol. Energy 86 (2012)
2852-2861
• R.P. Saini, J. Verma, Heat transfer and friction factor correlations for a duct
having dimple shape artificial roughness for solar air heaters, Energy 33
(2008) 1277-1287.
• M. Sethi, Thakur N.S. Varun, Correlations for solar air heater duct with
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27.  R. Kumar, R. Chauhan, M. Sethi, A. Kumar, Experimental study and
correlation development for Nusselt number and friction factor for
discretized broken V-pattern baffle solar air channel, Exp. Therm. Fluid Sci.
31 (2017) 56-75.
 A. Kumar, M.H. Kim, Thermal hydraulic performance in a solar air heater
channel with multiple V-type perforated baffles, Energies 9 (2016) 564.
 J. Park, Y.H. Jo, J.S. Kwak, Heat transfer in rectangular duct with perforated
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arrangement, Appl. Therm. Eng. 82 (2015) 194-205.
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solar air channel with broken multiple V-type baffles, Case Stud. Therm.
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28.  Kumar Anil, Kumar Raj, Maithani Rajesh, Chauhan Ranchan, Sethi
Muneesh, Kumari Anita, Kumar Sushil, Kumar Sunil, Correlation
development for Nusselt number and friction factor of a multiple type V-
pattern dimpled obstacles solar air passage, Renewable Energy 109 (2017)
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rectangular channels with varying number of ribbed walls. Int J Heat Mass
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V-shaped broken ribs. Int J Heat Mass Transf 2004;47:229–43.
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performance of three sides artificially roughened solar air heaters Solar
Energy 130 (2016) 46–59

29.  R. Kumar, R. Chauhan, M. Sethi, A. Kumar, Experimental study and
correlation development for Nusselt number and friction factor for
discretized broken V-pattern baffle solar air channel, Exp. Therm. Fluid Sci.
31 (2017) 56-75.
 Gilani,S.E., Hussain H. Al-Kayiem, Dereje E. Woldemicheal, Gilani, S.I.
Performance enhancement of free convective solar air heater by pin
protrusions on the absorber, Solar Energy 151 (2017) 173–185
 Leontiev, A.I., Kiselev, N.A., Vinogradov, Yu.A., Strongin, M.M., Zditovets,
A.G., Burtsev, S.A., Experimental investigation of heat transfer and drag on
surfaces coated with dimples of different shape, International Journal of
Thermal Sciences 118 (2017) 152-167