Mechanical Engineering

1. 1
CHAPTER - 1
INTRODUCTION
1.1SOLAR ENERGY
Several scientists have pointed out the relevance of alternate renewable
sources of energy for combating ‘Energy Crisis’. Among the renewable sources
of energy, solar energy offers a practical solution for the energy problem which
is clouding the prospects of mankind. Energy is regarded as a means to improve
the quality of life and increase the productivity and employment, thereby
dictating the regional, national and international policies and programs. The
energy needs of our country are increasing at a rapid rate, and indigenous
energy resources are limited and may not be sufficient in the long run to sustain
economic development. Enhancing the energy efficiency and minimizing the
energy intensity of the economy should obviously constitute the basis of a
timely energy strategy. The energy crisis forces individuals, organization and
governments to better utilize new and renewable sources of energy, which alone
can meet the energy problem. Several strategies have been adopted to meet the
situation such as energy conservation, use and application of renewable energy
technologies.
The appropriate proposition for the developing countries like India is to
harness non-conventional renewable energies on a significant scale. Renewable
energies are gaining importance against the conventional energy sources
because conventional energy sources are embedded with several constraints like
quantity and quality of reserve, logistics of transportation and environmental
pollution. Among the renewable energy sources such as wind energy, solar
energy, biomass and tidal energy, solar energy gains more prominence because
other sources involve high technological development. “Solar energy is the
energy of the future, not just an alternative”

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The sun is the most plentiful energy source for the earth. All wind, fossil
fuel, hydro and biomass energy have their origins in sunlight. Solar energy falls
on the surface of the earth at a rate of 120petawatts, (1 petawatt = 1015 watt).
This means all the solar energy received from the sun in one days can satisfied
the whole world’s demand for more than 20 years. We are able to calculate the
potential for each renewable energy source based on today’s technology Future
advances in technology will lead to higher potential for each energy source.
However, the worldwide demand for energy is expected to keep increasing at 5
percent each year. Solar energy is the only choice that can satisfy such a huge
and steadily increasing demand.
Figure 1: The Potential for Renewable Energy Sources
(Based on Today’s Technology level)

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Figure 2: Word Energy Demand and Forecast
There are several applications for solar energy, for instance: electricity
generation, photochemical, solar propulsion, solar desalination, and room
temperate control. The collection of solar energy and its transfer to electricity
energy will have wide application and deep impact on our society, so it has
attracted the attention of the researchers.
Figure 3: Electrical Energy Consumption Percentage of Total Energy
Production in 2008

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1.2 SOLAR COLLECTORS
Solar radiation has been identified as the largest renewable resource on
earth. Solar energy can be applied in different ways and also many different
methods for collecting the solar energy from incident radiation are available.
The use of concentrators in the forms of solar energy collectors in order to
concentrate sunrays for better usage is on the increase worldwide. To this effect,
different types of solar concentrators have being developed over the years for
various applications. Solar radiation has been identified as the largest renewable
resource on earth. Solar energy can be applied in different ways and also many
different methods for collecting the solar energy from incident radiation are
available
Concentrator is a device which used to concentrated large area sunlight
in to smaller area.

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CHAPTER – 2
LITERATURE SURVEY
[1]
A. Borah, S.M. Khayer and L.N. Sethi., for efficient drying of product
through indirect drying method, a compound parabolic concentrator (CPC) were
installed. Six numbers of semi-cylindrical parabolic concentrators were
interpolated on a receiver plate for direct conversion of solar energy to thermal
energy by trapping the maximum incident rays into metallic tubes which were
placed on focus lines of the parabolas. Experiments were carried to study the
comparative performance of a solar flat plate collector and compound parabolic
concentrator of same size. Average temperature rise of 9.50
C was observed
during the period. A manual solar tracking was facilitated along the two axes up
to 4.68o
vertical and 11.54o
horizontal. Average temperature increase of 11.2o
C
could be achieved over the ambient. Solar radiation trapping time at a constant
temperature level was increased by 1.5 hours in comparison to fixed CPC.
[2]
Charles Kutscher, Frank Burkholder, Kathleen Stynes., have prescribed about
the overall efficiency of a parabolic trough collector is a function of both the
fraction of direct normal radiation absorbed by the receiver (the optical
efficiency) and the heat lost to the environment when the receiver is at operating
temperature. The overall efficiency can be determined by testing the collector
under actual operating conditions or by separately measuring these two
components. It describes how outdoor measurement of the optical efficiency is
combined with laboratory measurements of receiver heat loss to obtain an
overall efficiency curve. Further, it presents a new way to plot efficiency that is
more robust over a range of receiver operating temperatures.
[3]
R. Forristall., proposed there report which describes the development,
validation, and use of a heat transfer model implemented in Engineering

6. 6
Equation Solver (EES). The model determines the performance of a parabolic
trough solar collector’s linear receiver, also called a heat collector element
(HCE). All heat transfer and thermodynamic equations, optical properties, and
parameters used in the model are discussed. The modeling assumptions and
limitations are also discussed, along with recommendations for model
improvement. The model was implemented in EES in four different versions.
Two versions were developed for conducting HCE design and parameter
studies, and two versions were developed for verifying the model and
evaluating field test data. One- and two-dimensional energy balances were used
in the codes, where appropriate. Each version of the codes is discussed briefly,
which includes discussing the relevant EES diagram windows, parameter tables,
and lookup tables. Detailed EES software instructions are not included;
however, references are provided. Model verification and a design and
parameter study to demonstrate the model versatility are also presented. The
model was verified by comparing the field test versions of the EES codes with
HCE experimental results. The design and parameter study includes numerous
charts showing HCE performance trends based on different design and
parameter inputs. Based on the design and parameter study, suggestions for
HCE and trough improvements and further studies are given. The HCE
performance software model compared well with experimental results and
provided numerous HCE design insights from the design and parameter study.
[4]
Hank Price et al., have proposed about parabolic trough solar technology is
the most proven and lowest cost large-scale solar power technology available
today, primarily because of the nine large commercial-scale solar power plants
that are operating in the California Mojave Desert. These plants developed by
Luz International Limited and referred to as Solar Electric Generating Systems
(SEGS), range in size from 14–80 MW and represent 354 MW of installed
electric generating capacity. More than 2,000,000 m2 of parabolic trough

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collector technology has been operating daily for up to 18 years, and as the year
2001 ended, these plants had accumulated 127 years of operational experience.
The Luz collector technology has demonstrated its ability to operate in a
commercial power plant environment like no other solar technology in the
world. Although no new plants have been built since 1990, significant
advancements in collector and plant design have been made possible by the
efforts of the SEGS plants operators, the parabolic trough industry, and solar
research laboratories around the world. This paper reviews the current state of
the art of parabolic trough solar power technology and describes the R&D
efforts that are in progress to enhance this technology. The paper also shows
how the economics of future parabolic trough solar power plants are expected to
improve.
[5]
R. McConnell, M. Symko-Davies, and H. Hayden., proposed their views of
about solar energy and its characteristics. Solar energy is more plentiful, more
predictable and is less site specific than wind. Despite solar energy advantages
and our best intentions, wind farms are common place while “sun farms” are
still a rarity. It seems inevitable that the scales will tip but the natural time
scales are too long (for the author at least). How do we pick up the pace. This
above contents represents the author’s view of the solution, which includes a
mixture of technology, commercial management, capital, collaboration and
influence. Dave Holland is the Managing Director of Solar Systems and a
Director of Renewable Energy Generators Australia – an industry group that
represents more than 90% of Australia’s renewable energy based generation
assets.
[6]
Soteris A. Kalogirou. In this paper a survey of the various types of solar
thermal collectors and applications is presented. Initially, an analysis of
environmental problems related to the use of conventional sources of energy is

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presented and the benefits offered by renewable energy systems are outlined. A
historical introduction into the uses of solar energy is attempted followed by a
description of the various types of collectors including flat-plate, compound
parabolic, evacuated tube, parabolic trough, Fresnel lens, parabolic dish and
heliostat field collectors. This is followed by an optical, thermal and
thermodynamic analysis of the collectors and a description of the methods used
to evaluate their performance. Typical applications of the various types of
collectors are presented in order to show to the reader the extent of their
applicability. These include solar water heating, which comprise thermo
syphon, integrated collector storage, direct and indirect systems and air systems,
space heating and cooling, which comprise, space heating and service hot water,
air and water systems and heat pumps, refrigeration, industrial process heat,
which comprise air and water systems and steam generation systems,
desalination, thermal power systems, which comprise the parabolic trough,
power tower and dish systems, solar furnaces, and chemistry applications. As
can be seen solar energy systems can be used for a wide range of applications
and provide significant benefits, therefore, they should be used whenever
possible.
[7]
Ted Collins all., Parabolic-trough solar water heating is a well-proven
renewable energy technology with considerable potential for application at
Federal facilities. For the United States, parabolic-trough water-heating systems
are most cost effective in the Southwest where direct solar radiation is high.
Jails, hospitals, barracks, and other facilities that consistently use large volumes
of hot water are particularly good candidates, as are facilities with central plants
for district heating. As with any renewable energy or energy efficiency
technology requiring significant initial capital investment, the primary condition
that will make a parabolic-trough system economically viable is if it is replacing

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expensive conventional water heating. In combination with absorption cooling
systems, parabolic-trough collectors can also be used for air-conditioning.
Industrial Solar Technology (IST) of Golden, Colorado, is the sole current
manufacturer of parabolic-trough solar water heating systems. IST has an
Indefinite Delivery/Indefinite Quantity (IDIQ) contract with the Federal Energy
Management Program (FEMP) of the U.S. Department of Energy (DOE) to
finance and install parabolic-trough solar water heating on an Energy Savings
Performance Contract (ESPC) basis for any Federal facility that requests it and
for which it proves viable. For an ESPC project, the facility does not pay for
design, capital equipment, or installation. Instead, it pays only for guaranteed
energy savings. Preparing and implementing delivery or task orders against the
IDIQ is much simpler than the standard procurement process. This Federal
Technology Alert (FTA) of the New Technology Demonstration Program is one
of a series of guides to renewable energy and new energy-efficient technologies.
It is designed to give Federal facility managers the information they need to
decide whether they should pursue parabolic-trough solar water heating or air
conditioning for their facility and to know how to go about doing so. Software
available from FEMP's Federal Renewables Program at the National Renewable
Energy Laboratory (NREL) enables preliminary analysis of whether parabolic-
trough collectors would be cost effective for any situation based on minimum
data.
This FTA describes the technology of parabolic-trough collectors, solar water
heating systems, and absorption cooling. It points out the types of situations
where parabolic-trough solar water heating is most likely to be cost effective
and describes the ESPC process available to Federal facilities for parabolic-
trough projects. In addition, sidebars provide indicators that a system will be
effective, tips for ensuring successful operation, and sources for determining

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system data. Case studies for a 10-year-old system at a county jail and for one
just starting construction at a Federal prison include economic evaluation data.

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CHAPTER – 3
OBJECTIVE & SCOPE OF OUR PROJECT
The objective of our project is to construct a solar concentrator which serves as
an energy utilizer for various applications. To design a parabolic trough to
produce heat energy by capturing naturally available sunlight. The process
output is depending upon light energy from the sun.

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CHAPTER – 4
SOLAR CONCENTRATOR
4.1 SOLAR CONCENTRATOR
Solar concentrator is a device which concentrates the solar energy
incident over a large surface onto a smaller surface. The concentration is
achieved by the use of suitable reflecting or refracting elements, which results in
increased flux density on the absorber surface compared to that existing on the
concentrator aperture. In order to get a maximum concentration an arrangement
for tracking sun’s virtual motion is required. An accurate focusing device is also
required. Thus the solar concentrator consists of a focusing device, a receiver
system and a tracking arrangement. Temperature as high as 3000 o
C can be got
from a solar concentrator. So they have potential application in both thermal
and photovoltaic utilization of solar power at high temperatures. Solar
concentrating device have been used for a long time.
4.2 TYPES OF CONCENTRATORS
4.2.1 STATIONARY COLLECTORS
Solar energy collectors are basically distinguished by their motion, i.e.
stationary, single axis tracking and two axes tracking, and the operating
temperature. Initially, the stationary solar collectors are examined. These
collectors are permanently fixed in position and do not track the sun. Three
types of collectors fall in this category:
a. Flat Plate Collector (FPC)
b. Compound Parabolic Collectors (CPC)
c. Evacuated Tube Collectors

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4.2.2.1 FLAT PLATE COLLECTOR (FPC)
A typical flat-plate solar collector is shown in Fig.4. When solar radiation
passes through a transparent cover and impinges on the blackened absorber
surface of high absorptivity, a large portion of this energy is absorbed by the
plate and then transferred to the transport medium in the fluid tubes to be
carried away for storage or use. The underside of the absorber plate and the side
of casing are well insulated to reduce conduction losses. The liquid tubes can be
welded to the absorbing plate, or they can be an integral part of the plate. The
liquid tubes are connected at both ends by large diameter header tubes. The
transparent cover is used to reduce convection losses from the absorber plate
through the restraint of the stagnant air layer between the absorber plate and the
glass. It also reduces radiation losses from the collector as the glass is
transparent to the short wave radiation received by the sun but it is nearly
opaque to long-wave thermal radiation emitted by the absorber plate
(greenhouse effect). 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.

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Figure 4: Flat-Plate Collector
4.2.1.2 COMPOUND PARABOLIC COLLECTORS (CPC)
CPC are non-imaging concentrators. These have the capability of
reflecting to the absorber all of the incident radiation within wide limits. Their
potential as collectors of solar energy was pointed out by Winston. The
necessity of moving the concentrator to accommodate the changing solar
orientation can be reduced by using a trough with two sections of a parabola
facing each other, as shown in Fig.5. Compound parabolic concentrators can
accept incoming radiation over a relatively wide range of angles. By using
multiple internal reflections, any radiation that is entering the aperture, within
the collector acceptance angle, finds its way to the absorber surface located at
the bottom of the collector.

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Figure 5: Compound Parabolic Trough
4.2.1.3 EVACUATED TUBE COLLECTORS
Conventional simple flat-plate solar collectors were developed for use in
sunny and warm climates. Their benefits however are greatly reduced when
conditions become unfavorable during cold, cloudy and windy days.
Furthermore, weathering influences such as condensation and moisture will
cause early deterioration of internal materials resulting in reduced performance
and system Failure. Evacuated heat pipe solar collectors (tubes) operate
differently than the other collectors available on the market. These solar
collectors consist of a heat pipe inside a vacuum-sealed tube, as shown in Fig.6.
ETC has demonstrated that the combination of a selective surface and an
effective convection suppressor can result in good performance at high
temperatures. The vacuum envelope reduces convection and conduction losses,
so the collectors can operate at higher temperatures than FPC. Like FPC, they
collect both direct and diffuse radiation. However, their efficiency is higher at
low incidence angles. This effect tends to give ETC an advantage over FPC in
day-long performance. ETC use liquid–vapor phase change materials to transfer
heat at high efficiency. These collectors feature a heat pipe (a highly efficient
thermal conductor) placed inside a vacuum-sealed tube. The pipe, which is a
sealed copper pipe, is then attached to a black copper fin that fills the tube

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(absorber plate). Protruding from the top of each tube is a metal tip attached to
the sealed pipe (condenser).The heat pipe contains a small amount of fluid (e.g.
methanol) that undergoes an evaporating-condensing cycle. In this cycle, solar
heat evaporates the liquid, and the vapor travels to the heat sink region where it
condenses and releases its latent heat. The condensed fluid return back to the
solar collector and the process is repeated. When these tubes are mounted, the
metal tips up, into a heat exchanger. Water, or glycol, flows through the
manifold and picks up the heat from the tubes. The heated liquid circulates
through another heat exchanger and gives off its heat to a process or to water
that is stored in a solar storage tank.
Figure 6: Evacuated tube collectors
4.2.2 SUN TRACKING CONCENTRATING COLLECTORS
There are two methods by which the sun’s motion can be readily tracked.
The first is the altazimuth method which requires the tracking device to turn in
both altitude and azimuth, i.e. when performed properly, this method enables
the concentrator to follow the sun exactly. Paraboloidal solar collectors
generally use this system. The second one is the one-axis tracking in which the

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collector tracks the sun in only one direction either from east to west or from
north to south. Parabolic trough collectors (PTC) generally use this system.
These systems require continuous and accurate adjustment to compensate for
the changes in the sun’s orientation. The collectors falling in this category are:
4.2.2.1 LINEAR FRESENAL REFLECTOR (LFR)
LFR technology relies on an array of linear mirror strips which
concentrate light on to a fixed receiver mounted on a linear tower as shown in.
Fig.7.The greatest advantage of this type of system is that it uses flat or
elastically curved reflectors which are cheaper compared to parabolic glass
reflectors. Additionally, these are mounted close to the ground, thus minimizing
structural requirements.
Figure 7: Linear Fresenal Reflector
4.2.2.2 PARABOLIC DISH REFLECTOR (PDR)
A parabolic dish reflector is a point-focus collector that tracks the sun in
two axes, concentrating solar energy onto a receiver located at the focal point of
the dish. The dish structure must track fully the sun to reflect the beam into the
thermal receiver. For this purpose tracking mechanisms similar to the ones

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described in previous section are employed in double so as the collector is
tracked in two axes.
The receiver absorbs the radiant solar energy, converting it into thermal
energy in a circulating fluid. The thermal energy can then either be converted
into electricity using an engine-generator coupled directly to the receiver, or it
can be transported through pipes to a central power-conversion system.
Parabolic-dish systems can achieve temperatures in excess of 15000
C. Because
the receivers are distributed throughout a collector field, like parabolic troughs,
parabolic dishes are often called distributed-receiver systems.
4.2.2.3 PARABOLIC TROUGH
A parabolic trough is a type of solar thermal collector that is straight in
one dimension and curved in the other dimension and with a polished metal
mirror. The energy of sunlight which enters the mirror parallel to its plane of
symmetry is focused along the focal lines, where the objects are positioned that
are intended to be heated. For example food can be prepared when the trough is
aimed to the sun is in its plane of symmetry. For other purpose, there is often a
Dewar tube, which runs the length of a trough at its focal line. The mirror is
oriented so that sunlight which it reflects is concentrated on the tube, which
contains a fluid which is heated to a high temperature by the energy of sunlight.
The hot fluid is further converted to steam and made to run the steam turbines.
The trough is usually aligned on a north-south axis and rotated to track
the sun as it moves across the sky each day as shown in Fig.8. Alternatively the
trough can be aligned on the east-west axis; this reduces the overall efficiency
of the collector due to cosine loss but only requires the trough to be aligned with
the change in seasons, avoiding the need for tracking motors. The daily motion
of the sun across the sky also introduces errors, greatest at the sunrise and

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sunset and smallest at solar noon. Due to these errors seasonally adjusted
parabolic troughs are generally designed with a lower concentration acceptance
product.
Heat transfer fluid runs through the tube to absorb the concentrated
sunlight. This increases the temperature of the fluid to some 400o
C. the heat
transfer fluid is then used to heat steam in a standard turbine generator. The
process is economical and for heating the pipe, thermal efficiency ranges from
60-80%. The overall efficiency from collector to grid, i.e. (electrical output
power)/(total impinging solar power) is about 15% similar to PV but less than
stirling dish collectors.
Figure 8: Parabolic Trough

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Table 1: Detailed Characteristics of Types of Solar Concentrator
Motion Collector Absorber
type
Concentration
Ratio
Temperature
0
c
Stationary FPC
ETC
CPC
FLAT
FLAT
TUBULAR
1
1
1-1.5
30-50
50-200
60-240
Single axis
tracking
LFR
PTC
TUBULAR
TUBULAR
10-40
15-45
60-250
60-300
Double axis
Tracking
PDR POINT
POINT
100-1000 100-500
Note: Concentration ratio is defined as the aperture area divided by the
receiver/absorber area of the collector.

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CHAPTER –5
METHODOLOGY
5.1 STUDY OF SOLAR CONCENTRATORS
Before discussing concentrators, a few words about the sun are in order.
Beyond the earth’s atmosphere the intensity of sunlight is about 1,350 watts
per square meter. Passage through the atmosphere depletes the intensity due to
absorption by various gases and vapors in the air and by scattering from these
gases and vapors and from particles of dust and ice also in the air. Thus, sun
light reaching the earth is a mixture of a direct (unscattered) and diffuse
Study of Concentrator
Testing
Fabrication
Design of Parabolic Trough
Selection of Suitable
Concentrator (Parabolic
Trough)

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(scattered) radiation. At sea level the intensity is reduced to approximately 1000
watts per square meter on a bright clear day. The intensity is further reduced on
overcast days.
Most concentrators utilize direct radiation only. These concentrators work
well on bright clear days, poorly on hazy days, and not at all on drab gray days
when the sunlight intensity is reduced and the light consists principally of
diffuse radiation. Another limiting factor is that the sun is not a point but has a
diameter equivalent to about one half degree of arc.
Although the discussion that follows deals with concentrators are only
portions of an energy collection system. To be useful the concentrated rays must
be directed to a target called receiver, which converts the rays into another form
of energy, heat. The concentrator and receiver must be matched for optimum
performance. Frequently, the receiver is expected to impart heat to a fluid in
order that the heat be utilized or dissipated. When the main purpose of
concentrator is to obtain heat effectively, then the combination of concentrator
and receiver must be carefully designed to reduce stray loss of energy from
either the concentrator or receiver.
5.2 SELECTION OF SUITABLE CONCENTRATOR
We have chosen the parabolic trough because,
 It delivers high temperature.
 Better efficiency compared to other concentrators.
 High performance with low cost.

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5.2.1 COMPONENTS OF PARABOLIC TROUGH
5.2.1.1 REFLECTOR
PTCs are made by bending a sheet of reflective material into a parabolic
shape. A metal black tube, covered with a glass tube to reduce heat losses, is
placed along the focal line of the receiver. When the parabola is pointed towards
the sun, parallel rays incident on the reflector are reflected onto the receiver
tube. It is sufficient to use a single axis tracking of the sun and thus long
collector modules are produced. The collector can be orientated in an east–west
direction, tracking the sun from north to south, or orientated in a north–south
direction and tracking the sun from east to west. The advantages of the former
tracking mode is that very little collector adjustment is required during the day
and the full aperture always faces the sun at noon time but the collector
performance during the early and late hours of the day is greatly reduced due to
large incidence angles (cosine loss). North–south orientated troughs have their
highest cosine loss at noon and the lowest in the mornings and evenings when
the sun is due east or due west. Over the period of one year, a horizontal north–
south through field usually collects slightly more energy than a horizontal east–
west one. However, the north–south field collects a lot of energy in summer and
much less in winter. The east–west field collects more energy in the winter than
a north–south field and less in summer, providing a more constant annual
output. Therefore, the choice of orientation usually depends on the application
and whether more energy is needed during summer or during winter.
Parabolic trough technology is the most advanced of the solar thermal
technologies because of considerable experience with the systems and the
development of a small commercial industry to produce and market these
systems.

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PTCs are built in modules that are supported from the ground by simple
stands at either end. PTCs are the most mature solar technology to generate heat
at temperatures up to 4000
C for solar thermal electricity generation or process
heat applications.
5.2.1.2 RECEIVER
The receiver of a parabolic trough is linear. Usually, a tube is placed along
the focal line to form an external surface receiver. The size of the tube, and
therefore the concentration ratio, is determined by the size of the reflected sun
image and the manufacturing tolerances of the trough. The surface of the
receiver is typically plated with selective coating that has a high absorptance for
solar radiation, but a low emittance for thermal radiation loss.
A copper tube is usually placed around the receiver tube to reduce the
convective heat loss from the receiver; the copper usually has an antireflective
coating to improve transmissivity. One way to further reduce convective heat
loss from the receiver tube and thereby increase the performance of the
collector, particularly for high temperature applications, is to evacuate the space
between the glass cover tube and the receiver.
5.2.1.3 TRACKING MECHANISM
A tracking mechanism must be reliable and able to follow the sun with
a certain degree of accuracy, return the collector to its original position at the
end of the day or during the night, and also track during periods of intermittent
cloud cover. Additionally, tracking mechanisms are used for the protection of
collectors, i.e. they turn the collector out of focus to protect it from the
hazardous environmental and working conditions, like wind gust, overheating
and failure of the thermal fluid flow mechanism.

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The electronic systems generally exhibit improved reliability and tracking
accuracy. These can be further subdivided into the following:
 Mechanisms employing motors controlled electronically through
sensors, which detect the magnitude of the solar Illumination.
 Mechanisms using computer controlled motors with feedback control
provided from sensors measuring the solar flux on the receiver.

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CHAPTER – 6
DESIGN & CALCULATIONS
6.1 DESIGN OF PARABOLIC TROUGH
After conducting more research on solar energy and solar collection, the
decision was made to attempt to build a parabolic trough solar concentrator. In a
parabola all of the incoming rays from a light source are reflected back to the
focal point of the parabola. If the said parabola is extended along an axis
(becoming a trough) the solar rays are concentrated along a line through the
focal point of the trough. The focal point of a parabola is located at 1/4a, if the
equation of the parabola is y = ax2
. The parabolic trough selected fit the
equation y = .04167x2
from x = -26.75 cm to x = 26.75 cm. This equation was
chosen to yield a focal point located at 13.37 cm above the vertex of the
parabola, for ease of construction. Initial sketches and drawings are located. A
mathematical model was developed that would help determine the temperature
of the water leaving the parabolic trough, knowing the temperature of the water
entering the trough and the amount of insolation absorbed by the receiver. The
arrangement for the parabola was made out of steel rod. It would be attached to
the edges which would allow for proper angling of the parabolic trough. The
entire trough was small enough to allow for easy manual adjustment for solar
tracking. The receiver chosen was a simple, half-inch copper pipe, painted black
to absorb more incident radiation. Copper was chosen because of its high
thermal conductivity and it is relatively inexpensive. The water source was
planned as a small reservoir located above the trough, with gravity assisted flow
through the trough, to another reservoir used for collection of the heated water.
But, based on the location of testing, a simple garden hose was used with a
compression fitting to attach the hose to the copper pipe. This proved to be
easier and more efficient, as well as significantly less expensive. A piece of

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polished Aluminum was used for the reflective surface. With the design stage
complete construction began.
Figure 9: Parabolic Graph

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6.2 CALCULATION
Length of Parabola from X1 to X2 is ‘S’
Let p = 2f, & q=√ (t2
+q2
), P is the distance
From Y-axis to point X
P=53.5 cm
T=2(26.75)-53.5
Q=√ (53.52
+53.52
)
Q=75.6604 cm
S=[ (p*q/t) + t ln ((p + q)/t) ]

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S = [(53.5*75.66)/53.5+53.5 ln ((53.5+75.66)/53.5)]
S = 122.81 cm
Size of Rectangular Sheet Metal:

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CHAPTER – 7
FABRICATION
7.1 FABRICATION OF PARABOLIC TROUGH
The plan for construction of solar concentrator consisted of the following.
Based on the initial design sketches materials were bought at Home Depot. A
four feet long piece of ½ inch copper pipe, black heat resistant spray paint, heat
absorbing metallic silver spray paint, an aluminium sheet metal (9900 cm2
),
measuring tape, sheet metal cutter, drilling machine, standard garden hose and
construction materials were purchased. The next step consisted of carefully
drawing a square of (110*90) cm using marker and steel rule on the aluminium
sheet metal. An origin x and y axes were chosen, and the points of the parabola
were plotted. The plan was to fix the sheet metal over a rectangular frame of
size same as that of the sheet metal since the sheet metal could not be welded
we’ve decided to bend the sheet to the parabolic shape and attach the ends of the
sheet with steel rod so that welding action can be done over the steel rod to
achieve the best parabolic trough. The sheet metal and the additional steel rods
are chopped by the aid of cutting machines. Next the copper pipe is cut
according to the sheet metal. The copper pipe is used as a heat absorber or solar
collector. The construction of parabolic trough is to rotate the trough according
to the sunlight which enhances the tracking system but cost wise they are found
to be high a simple compact parabolic trough was planned to construct. To build
the base of the solar collector two triangles shaped steel rod was welded in v-
shaped arrangement followed by the supporting stand with a required height. It
worked out to be a strong connection. To attach the Aluminium sheet to the
steel rod, it was cut into the proper rectangle size using the sheet metal cutter.
Holes were drilled along the edges at increments of 2 inches to serve as places
to screw the Aluminium to the steel rod. Next the Aluminium sheet was

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manually bent down into the parabolic frame and attached with the steel rod.
Some trouble was encountered here because the Aluminium wasn’t rigid
enough to hold a consistent shape between the two steel rod pieces. The
Aluminium parabola seemed to be nearly perfect. The next items purchased
included copper pipe and garden hose pipe. The copper pipe was sanded lightly
and sprayed with flat black paint. In order to set the copper pipe in the focal
point a separate stand was constructed to move it in vertical position. One end
of the pipe is fitted with garden hose pipe which serves as an inlet of fluid and
the other end is left free to the collector tank. Having finished the construction,
all that was left was putting it all together. The pieces were brought to the test
site, and the trough was attached to the base. The pipe fixing stand was also
welded with the trough holding stand so that the construction found to be
finished. The painted copper pipe is placed in the holding stand and the garden
hose pipe is attached with proper required connection. The solar concentrator
was ready for testing.
7.2 LIST OF MATERIALS
Table 2:
S.NO MATERIALS TYPE OF MATERIALS QUANTITY
1. Parabolic Trough aluminium sheet metal (9900cm2
), 1
2. Coating metallic silver spray paint 200 ml
3. Absorber ½ inch copper pipe 4 ft.
4. Water Collector &
Receiver Tank.
steel or plastic As required
5. standard garden hose Rubber As required

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7.3 TESTING
In order to test the solar concentrator, the testing equipment’s are
needed to be purchased. The major testing methods include the use of Vernier
technology which has sensors and preloaded software and also the pyrometers.
Since our project is a miniature creation we've purchased ordinary thermometer
from amazon online market place to measure the temperature of the solar
concentrator. The testing went smoothly since the weather condition are apt for
testing of our project. First test is that the copper pipe was filled with water and
kept undisturbed in the sunlight for about half an hour. After the respective time
was over the temperature of the water was noted as 45°C then the second test
was followed by the next half an hour. In this testing the required arrangement
of a solar concentrator was setup. Following the previous testing method
Copper tube was set at the focal point of the parabolic trough and left for half an
hour. The temperature was noted using the thermometer and was found to be
above 70°C. The difference in the results prescribes the working condition of
our solar concentrator.

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CHAPTER – 8
ADVANTAGES, DISADVANTAGES AND APPLICATIONS
8.1 ADVANTAGES
1. It helps in reducing the cost by replacing an expensive large receiver
by a less expensive reflecting or refracting area.
2. Due to concentration on a smaller area, the heat loss area is reduced.
3. Further the thermal mass as much smaller than that of a flat plate
collector and hence transient effects are small.
4. The delivery temperature being high, a thermodynamic match between
the temperature level the task occurs.
5. It increases the intensity by concentrating the energy available over a
large surface onto a smaller surface (absorber).
8.2 DISADVANTAGES
1. Non uniform flux on absorbers.
2. Maintenance is high.
3. Wide variation in shape.
4. Higher the concentration of the collector, higher is the precision of
optics and more is the cost of the unit.
8.3 APPLICATIONS
1. Cooking
2. Water heating
3. Process heat
4. Water treatment
5. Power generation

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CHAPTER – 9
CONCLUSION
In this project, the Solar Concentrator has fulfilled the criteria for
practical applications: being technically feasible, eco-friendly, customer
oriented, locally available, saving fossil fuels and providing more employment
opportunities. If such technology is adopted on a large scale, then the energy
crisis can be solved in our country. It is a decisive step towards becoming a
developed nation. By this project, the energy producing technology can be
changed and it became very easier to install the energy producing method for
the long life.

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CHAPTER – 10
PHOTOGRAPH
Figure 10: Completed Solar Concentrator

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CHAPTER - 11
REFERENCES
1. A. Borah, S.M. Khayer and L.N. Sethi., “Development Of A Compound
Parabolic Solar Concentrator To Increase Solar Intensity And Duration
Of Effective Temperature”, International Journal of Agriculture and Food
Science Technology, ISSN 2249-3050, Volume 4, Number 3 , pp. 161-
168, 2013.
2. Charles Kutscher, Frank Burkholder, Kathleen Stynes., “Generation Of A
Parabolic Trough Collector Efficiency Curve From Separate
Measurements Of Outdoor Optical Efficiency And Indoor Receiver Heat
Loss”, October 2010.
3. R. Forristall., “Heat Transfer Analysis And Modelling Of A Parabolic
Trough Solar Receiver Implemented In Engineering Equation Solver”,
October 2003.
4. Hank Price et all., “Advances In Parabolic Trough Solar Power
Technology”, Journal of Solar Energy Engineering, Vol. 124/109, MAY
2002.
5. R. McConnell, M. Symko-Davies, and H. Hayden., “Solar
Concentrators For The Generation Of Electricity Or Hydrogen”, May
2005.
6. Soteris A. Kalogirou., “Solar Thermal Collectors And Applications”,
Progress in Energy and Combustion Science, 231–295, 2004.
7. Ted Collins et all., “Parabolic-Trough Solar Water Heating”.