Experimental and Computational Fluid Dynamics Analysis of Ashish N. Sarode

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International Conference on Global Trends in Engineering, Technology and Management (ICGTETM-2016)
Experimental and Computational Fluid Dynamics Analysis of
a New Flat Plate Solar Collector
Ashish N. Sarode#1, Dr. Atul A. Patil*2, V.H.Patil#3
# M.E. Student, Department of Mechanical Engineering, GF's Godavari College of Engineering, Jalgaon,
Maharashtra, India.
* Associate Professor, Department of Mechanical Engineering, GF's Godavari College of Engineering,
Jalgaon, Maharashtra, India.
# Associate Professor, Department of Mechanical Engineering, GF's Godavari College of Engineering,
Jalgaon, Maharashtra, India.
Abstract—This paper present the investigation of
performance and reliability of a new design flat plate
solar collector.Flat plate collector is one of the
important solar energy trapping device which uses air
or water as working fluid. Usually all flat plate
collectorabsorbers are made up ofcopper or
aluminium sheets, which limits on the heat collection
surface transfer area.The specific objective of this
study is to develop new models and improved the
efficiency of the solar water heater by exchanging the
absorber & copper tube arrangement with fabrication
of a simple copper box as a collector.The
Computational Fluid Dynamics (CFD) software has
been used for simulation of new flat plate collector.
Experimentation conducted on new flat plate collector
for particular period ofvarious days and data is
maintained as per days.The experimental results of
water outlet temperature are validated with the results
obtained by using computational fluid dynamics
(CFD) tool and there is a good agreement in between
them.
Keywords—Flat Plate Solar Collector (FPSC),Solar
water heater, Computational Fluid Dynamics (CFD).
I. INTRODUCTION
The rate at which the non-renewable energy are
utilized or depleted it is need to be focus on renewable
energy resources. Many types of renewable energy are
available but conversion technology of this energy
into usable form is not effectively and more
complicated. The sun is a good example of those
resources which undergo a faster replenishment rate
within a relatively short time than the rate at which
non-renewable energy is utilized or depleted[1]. The
energy of the sun is generated from the nuclear fusion
of its hydrogen into helium, with a resulting mass
depletion rate of approximately 4.7 × 106 tons per
second. The earth’s population currently needs 15
terawatts of power in total, but the solar radiation that
reaches the earth on a continuous basis amounts to
120,000 terawatts; only fraction of the suns energy
reaching the earth will cover the bulk of energy
requirements [2].
The sun is a sphere of intensely hot gaseous matter
with a diameter of 1.39 X 109 m. The solar energy
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strikes our planet a mere 8 min and 20 s after leaving
the giant furnace, the sun which is 1.5 X 10 11 m away.
The sun hasan effective blackbody temperature of
5762 K [3].Now-a-days, 80% of total energy is
produced by means of fossil fuels, and this massive
utilization is leading to the overtiredness of these
resources and imposes a real threat to the environment,
mainly through global warming and acidification of
water cycle[4].
The demand for renewable energy is increasing due
to the rapid growth of industrialization and the
excessive use of fossil fuels which has adverse effects
on global climate change. Solar energy is one of the
cleanest, most abundant and environmental friendly
sources of renewable energy. To obtain maximum
thermal energy from incident solar radiation, welldeveloped solar conversion technology today solar
water heaters with different configurations and
designs have been used for various applications [5],
[6], [7], [8], [9].
Solar water heaters play a vital role in low
temperature applications especially in domestic sector.
Solar water heater is one of the most successful solar
technologies. Currently, world’s demand of energy
has dramatically increased; furthermore, process to
collect hot water by solar radiation is expensive [10].
The use of solar water heaters (SWH) is encouraged to
produce domestic hot water because SWH can
substantially reduce primary energy consumption
compared with conventional water heaters [11].Flat
plate collectors (FPC) are the most used type of
collector. FPC is usually employed for low
temperature applications up to 100 0C, although some
new types of collectors employing vacuum insulation
can achieve slightly higher values [12].A typical flat
plate collector is shown in figure 1.
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.
Fig. 1 A typical flat plate collector
II. CONSTRUCTIONAL DETAILS
A passive system was selected as the basis for the
design of flat plate collectors which do not necessitate
any electricity and relay. Principle of passive system is
based on natural circulations of hot water, gravity feed
and water pressure. A new flat-plate solar collector
has the simplest designs and requires neither tracking
nor as much maintenance as the other collector
designs.In passive type flat plate collector, we
changed the copper tubes arrangement by simple
putting a copper box as flat plate of dimensions 1100
x 1100 x 15 mm in collector frame. The thickness of
copper flat plate is 1 mm having 22 gauges.Figure 2
shows the realview of new flat plate collector.
FPC is usually permanently fixed in position and
requires no tracking of the sun. The collectors should
be oriented directly towards the equator, facing south
in the northern hemisphere and north in the southern.
The optimum tilt angle of the collector is equal to the
latitude of the location with angle variations of 10–150
more or less depending on the application [13].
The solar radiation is incident on the absorber plate.
The absorber plate is made of copper material because
of its high thermal conductivity which will rapidly
absorb heat from sun's rays and quickly transfer that
heat to the tubes or fins which will transfer heat to
thewater[14], [15]. The main pipe is made of material
Fig. 2 Real view of new flat plate collector
of copper to transfer the absorbed heat to the water, a
dark-coloured shows the absorber and a cover
The copper boxis fixed in collector frame with a
glass[16]. Casing is providing to the collector to
transparent cover to reduce the convection and
reduce the heat transfer losses by convection and
radiation losses. The casing is made of aluminium
radiation. It is made of Aluminium or wooden material
with black painted. The provision for feed waterfrom
depending upon the applications [17].Most solar water
the water tank at the inlet as given from lower side of
heater designs used for single family are closed and
the frame into the copper box and outlet of hot water
opened solar water heating systems. These two
is given from the another end. The rise of the water
systems are categorized into two groups:forced
temperature inside the copper box collector is due to
circulation and natural convection. The advantages of
the absorption of incident solar radiation which gives
thermosyphon systems are more reliable and longer
rise to water uprising motion by thermosyphon
life than forced circulation systems with no need of
principle.The technical specifications of solar water
pumps and controllers[18], [19].
heating system are given in Table I.
Manjunath M S states foranunglazed solar collector
with an innovative serratedfined tube as well as
TABLE I
another diametrically placed planar fin bifurcating the
TECHNICAL SPECIFICATIONS OF NEW FLAT PLATE
absorber tubepassage increases the heat transfer flux
COLLECTOR
by lowering the flow rates. These results validated
using Computational fluid dynamics[20]. The
Particular
Specification
objective of this work is to experimentally investigate
the water outlet temperature of solar flat plate Collector dimensions (Length
1.25 m x 1.25 m x 0.080 m
x Width x Thickness)
collector.Fluid flow and heat transfer in the collector
panel are studied by means of computational fluid
Collector type
Flat plate
dynamics
(CFD)
simulation.The
measured
Number of glass covers
1
experimental temperatures are compared to the
Cover
material
Low
iron
glass
temperatures determined by the CFD model and there
Cover thickness
4 mm
is a good similarity between the measured and
calculated results.The influences of different operating
Cover transmission
94%
conditions such as flow rate, properties of solar
Box dimensions
1.1 m x 1.1 m
collector fluid, solar collector fluid inlet temperature
(Length x Width)
are studied[21].
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Thermal conductivity of plate
material
386 W/m °C
Copper sheet thickness
1 mm (22 gauge)
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Collector heat absorber area
1.44m2
Insulation material
Rockwool
Thermal conductivity of
insulating material
0.045 W/m °C
Insulation thickness
30 mm
Sheet Material of collector tray
Aluminium
flat plate collectors are oriented in south direction that
it receives maximum solar radiation. Two digital
thermometers are required whose ranges up to 150 0C
for measurement inlet and outlet temperatures. Digital
Thermometer 1 is fitted in the inlet of solar water
heating system for measuring the inlet cold water
temperature and Thermometer 2 is fitted in the exit of
the collector for measuring the hot water
temperature.Flow meter is also fitted in the inlet side
system to measure the flow of water before the water
is admitted in the collector.
The 3-D view of copper made flat plate collector is as
shown in figure 3.
Fig. 5The closed view of Experimental setup for solar water heating
system
Fig. 3 3Dview of flat plate collector
III. EXPERIMENTAL SETUP AND
PROCEDURE
1) Experimental setup:
The tests were conducted at the GF’s Godavari
college
of
Engineering,
Jalgaon
(20.9980°N,75.5667°E), State- Maharashtra, India.
The schematic diagram of the thermosyphon flat plate
solar water heating system is shown in figure 4. The
system consists of flat plate collectors, storage tank
and connecting pipes. The flat plate collectors are
oriented in south direction that it receives maximum
solar radiation.Figure 4 shows the schematic
representation of experimental setup [22].
Fig. 4 Schematicrepresentation ofExperimental Setup
Figure 5 shows the closed view of experimental
setup for solar water heating system.The system
consists of flat plate collectors, two digital
thermometer, flow meter and connecting pipes.The
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2) Procedure for test Run:
The cold water storage tank filled with 500 litres of
water after proper filtration. The valve was opened to
allow water flow to the circulating pipes. Water flows
through the collector at a constant flow rate during all
the measurements. A part ofincidence solar radiation
on the glass cover is reflectedback to atmosphere and
remaining is transmitted inside thesolar collectors and
the solar radiation is absorbed by the water.Due to the
absorption of solar radiation, water temperature
increases and the water starts emitting long
wavelength radiation which is not allowed to escape to
atmosphere due to presence of glass cover. The
insulation provided at the bottom and all the sides of
solar collectors and glass cover serves the purpose of
reducing direct convective losses to the ambient which
further becomes beneficial for rise in water and solar
collectors temperature respectively.The heated water
moves upward due to decrease indensity whereas the
colder working fluid settled at thelower portion due to
more in density. The hot water is collected from the
outlet which isconnected to the solar hot water storage
tank which has a valve to allow tapping when needed
for use. Cold watertemperature (0C), solarcollector
temperature (0C), ambient temperature (0C) and hot
water temperature (0C) were recorded at 1 hour
intervals.
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The results were recorded after performing the
measurement of important operating parameters of the
experimental setup at selected location as per the
procedure specified during the experimental work.
The tests were conducted from 11.00 A.M. to 5.00
P.M. hourly. Throughout the complete trials
conducted, theday was sunny and no any cloudy
conditions were present[23].
high temperature and pressure gradients are finely
meshed.Meshing domain of flat plate collector is
IV.CFD SIMULATION
1) Modeling of Flat Plate Collector:
The 3-D model for new flat plate collector is
created using CAD Package CATIA V5 R19. It is
imported in Ansys fluent workbench. The extra length
added for pipe at inlet and outlet flat plate collector
which helps in reducing the non-uniformity of flow.
The geometrical specifications of the flat plate
collector have chosen somewhat arbitrarily. Collector
box is 1100 x 1100 mm. Inlet and outlet tube diameter
is di=d0=0.01m and thickness 15mm of copper
material.
Generally this model is designed and applying
heat transfer from top face to fluid present in the flat
plate collector.The model of flat plate collector is
shown in figure 6.
Fig. 6Model of flat plate collector
Then all the parts are defined i.e. inlet is defined as
Inflow, outlets as Outflow and Top Face.
shown in figure 7.
Fig. 7Meshing domain of flat plate collector
3. Physics of The Simulation For CFD Analysis:
a) Initial Assumptions:
Keeping inlet temperature to new flat plate
collector constant for each observations and mass flow
rate of water assumed arbitrarily for inlets of new flat
plate collector.
b) Viscous Model:
The laminar model is selected to analyze the
heat transfer and contour presentation. Energy model
is set to ON position which permits heat transfer
analysis.
2. Grid Generation of Flat Plate Collector:
The ANSYS ICEM-CFD is used for discretization
of domain. Initially a relatively coarser mesh is
generated. This mesh contains tetrahedral cells having
triangular faces at the boundaries. Care is taken to use
tetrahedral cells as much as possible. It is meant to
reduce numerical diffusion as much as possible by
structuring the mesh in a well manner, particularly
near the wall region. Later on, a fine mesh is
generated for this fine mesh, the edges and regions of
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c) Boundary Conditions:
Boundary conditions are used according to
the need of the model. Boundary conditions used at
inlets are mass flow rate of water and at outlets static
pressure is applied.
d) Solver Parameters:
The high resolution scheme and Auto-time
scale is used for convergence control. The
convergence criteria are RMS residual type and
convergence rate 1e-03 is used for mass and
momentum etc. which gives the water outlet
temperature from flat plate collector configuration
after certain number of iterations. The general
FLUENT simulation model of flat plate collector is
shown infigure 8.
Fig. 9 Variations in water outlet temperature vs. Daysat 3 P.M.
The experimental test has been carried out at 11
A.M. to 5 P.M. hourly for five consecutive days from
1st to 5th April 2015.It is observed from the figure 9
water outlet temperature from simulation of new flat
plate collector is greater than experimental results.
Increase in water outlet temperature of about2 to 6 %
in simulation of new flat plate collector as compared
to experimental results. New flat plate collector shows
maximum water outlet temperature around 3 P.M.
Increase in water outlet temperature for new flat plate
collector is due to increase in heat transfer area.
VI. CONCLUSIONS
Fig. 8FLUENT simulation model of flat plate collector
The general simulation parameters with solid fluid
assembly are summarized as given below in table II.
TABLE II
DETAILS OF SIMULATION PARAMETER
Parameter
Ansys Fluent
Domain of simulation
Flat plate collector
Laminar model
Viscous
Heat Transfer model
Thermal Energy
Fluid
Water
Solid
Copper
Reference Pressure
1 atm.
Inlet
Mass flow rate and
ACKNOWLEDGMENT
Temperature of Fluid
Outlet
Static pressure
Discretization
High Resolution
V. RESULT AND DISSCUSSION
88
Temperature (0C)
The following conclusions may be drawn from the
present study that new Flat plate solar water collector
is successfully designed through Experimental
analysis and validated using CFD simulation. The new
proposed design increase heat transfer rate by
increasing surface collector area.
1. It is observed from experimental results; the
water outlet temperature from collector is
linearly increases with increase in day passes.
2. It is also concluded from the results that the
maximum outlet temperature is reached at
3.00 P.M on 5th April with a maximum
temperature up to 850 C experimentally.
3. It has been observed that outlet temperature
of water in simulation greater than
experimental results of particular days.
87
I wish tothank Dr. D. S. Deshmukh, HO.D.
Department of Mechanical Engineering of S.S.B.T.
college of Engineering & Technology, Bambhori,
Jalgaon, Prof. Tejas G. Patil & Prof. Tushar A. Koli,
Department
of
Mechanical
Engineering,GF’s
Godavari college of Engineering, Jalgaonfor their
creative
suggestion,
constantsupport
and
encouragementto complete work. I am also thanks to
GF’s
Godavari
college
of
Engineering,
Jalgaonvaluable co-operation to accomplish this work.
86
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1-Apr 2-Apr 3-Apr 4-Apr 5-Apr
Days
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