Project report for concentrated parabolic trough collector under hand layup method

1. ACKNOWLEDGEMENT:
ALLAH ALMIGHTY, the only single source of certainty and
knowledge for us in this universe. We are very much thankful to ALLAH ALMIGHTY for
bestowing us with this report.
Heartiest thank to Mr. Qasim Ali Tatla, our project advisor, with full fledge respect
and protocol whose towering personality always enlightens the passions to achieve our goals!
Whose kind counseling tips and courteous attitude always backed us up to go on conquering the
horizons of knowledge and skills. Also regards to, other faculty members of Mechanical
department, for affectionate and respectful attitude towards us.

2. Table of Contents
ACKNOWLEDGEMENT:........................................................................................................... 1
1. Abstract:................................................................................................................................. 6
2. Introduction:.......................................................................................................................... 7
2.1 Need:..................................................................................................................................... 7
2.2 Renewable Energy resources of Pakistan: ............................................................................ 7
3. Literature Review: ................................................................................................................ 9
3.1 Background Research:...................................................................................................... 9
3.2 Early commercial adaption: ............................................................................................. 9
3.3 Currently Working Plants based upon Parabolic trough collectors...................................... 9
3.4 Solar Radiations: .............................................................................................................. 9
3.4.1 Direct radiation: ........................................................................................................... 10
3.4.2 Diffuse radiation: ......................................................................................................... 10
3.4.3 Reflexed radiation:....................................................................................................... 10
3.4.4 Global radiation: .......................................................................................................... 10
3.5 Solar Collectors:.................................................................................................................. 10
3.5.1 Current Solar Concentration Technologies:................................................................. 11
3.6 Parabolic Trough Technology: ........................................................................................... 11
3.6.1 Working Principle:....................................................................................................... 11
3.6.2 Suitable Materials for Collector:.................................................................................. 12
3.6.3 Suitable Materials for Absorber:.................................................................................. 12
3.6.4 Evacuated Tube Absorbers:......................................................................................... 13
3.6.5 Heat Transfer Fluids: ................................................................................................... 13
3.6.6 Thermal Storage:.......................................................................................................... 14
3.6.7 Optimum solar Flux Extraction: .................................................................................. 14
3.6.8 Tracking System: ......................................................................................................... 14
3.6.9 Parabolic trough power plant Layout: ........................................................................ 14
4. Aims and Objectives: .......................................................................................................... 15
5. Methodology:....................................................................................................................... 16
5.1 Calculations of Geometrical Parameter: ........................................................................ 16
5.2 Software Based Designing:............................................................................................ 18
5.3 Experimentation:............................................................................................................ 20

3. 6. Results:................................................................................................................................. 21
6.1 Case-I ............................................................................................................................. 21
6.2 Case-II............................................................................................................................ 21
6.3 Case-III........................................................................................................................... 22
6.4 Case-IV........................................................................................................................... 23
6.5 Case-V............................................................................................................................ 23
6.6 Case-VI........................................................................................................................... 24
6.7 Case-VII ......................................................................................................................... 25
7. Conclusion: .......................................................................................................................... 26
8. Future Perspectives:............................................................................................................ 26
9. References............................................................................................................................ 27

4. List of Figures:
Figure 2.1 Pakistan Direct Normal Solar Radiations Annual Figure............................................ 7
Figure 2.2 Estimated Renewable Energy Share in Global Final Energy Consumption (2011) [1]
......................................................................................................................................................... 8
Figure 2.3 Renewable power capacity........................................................................................... 8
Figure 3.1 Components of Solar Radiation.................................................................................. 10
Figure 3.2 Schematic Of Concentrating Solar Power Units ....................................................... 11
Figure 3.3 Components and Concentration of rays at the focal point of Parabolic Trough ........ 12
Figure 3.4 Configuration of Evacuated Receivers...................................................................... 13
Figure 3.5 Schematic of a Parabolic Trough power plant with a thermal storage syst................ 14
Figure 5.1 Visualization of Solar Beam Angle............................................................................ 17
Figure 5.2 Relationship between absorber diameter and rim angle............................................. 17
Figure 5.3 3D Modeling in Pro_E................................................................................................ 18
Figure 5.4 Ground supports and trough supporting trusses ......................................................... 19
Figure 5.5 Cross-section of Evacuated annular tube.................................................................... 19
Figure 6.1 Experimentation with Aluminum trough and black absorber .................................... 21
Figure 6.2 Experimentation with Silver coated collector and black absorber tube .................... 21
Figure 6.3 Experimentation with Aluminum foil trough and black absorber tube...................... 22
Figure 6.4 Experimentation with Aluminum Silver metal sheet collector and black absorber tube
....................................................................................................................................................... 23
Figure 6.5 Experimentation with Aluminum Silver metal sheet and black absorber tube .......... 23
Figure 6.6 Experimentation with Mirrors as reflecting surface and evacuated glass tube .......... 24

5. List of Tables:
Table 3.1 List of Power Stations using Parabolic Trough Collectors. [2] [3]_______________ 9
Table 3.2 Suitable Materials for collector. [4] ______________________________________ 12
Table 3.3 Suitable Materials for Absorber. [4] _____________________________________ 12
Table 3.4 Heat transfer fluids with application in solar parabolic trough fields. [6] _________ 13
Table 5.1 Summary of PTC key features. _________________________________________ 18
Table 6.1 Experiment data for temperature rise in Case-I _____________________________ 21
Table 6.2 Experiment data for temperature rise in Case-II ____________________________ 22
Table 6.3 Experiment data for temperature rise in Case-III____________________________ 22
Table 6.4 Experiment data for temperature rise in Case-IV ___________________________ 23
Table 6.5 Experiment data for temperature rise in Case-V ____________________________ 24
Table 6.6 Experiment data for temperature rise in Case-VI ___________________________ 24
Table 6.7 Experiment data for temperature rise in Case-VII ___________________________ 25

6. 1.Abstract:
This report presents the designing of a parabolic trough collector with a rim
angle of 80° and discusses the experimentation on an existing parabolic trough collector unit with
a rim angle 90°, length 32 inch and aperture area 1152 inch2
. The purpose of experimentation is to
increase the temperature of hot water through absorber by hand layup method using different
techniques including different coatings, mirrors and evacuated glass tube round the absorber.
Designing has been done considering optimum values and materials as in case of commercial units.
On available PTC unit, effects of ambient temperature, air velocity, different coatings and
evacuated glass tube have been explained numerically and graphically. Overall, report explains
the thorough designing and improving techniques for hot water generation by a hand layup method.

7. 2. Introduction:
2.1 Need:
Energy has become the highest concerning word as for government’s point of view. As
the population of the world going on increasing, the non-renewable resources are declined Day by
day (e.g. fossil foils). Scientist’s estimated 50% increase in worldwide energy consumption in
2030 and 70% to 100% in 2050. The bio and fossil fuels cannot overcome this energy crisis in
future. Each year, the sun sends over a billion terawatt hours of energy to the Earth, which is equal
to 60,000 times the world's electricity needs.so, the world is moving towards the solar energy.
Renewable energy resources are becoming many valuables due to continuously decrease
in conventional energy sources. Sun energy which is sometimes called as solar energy is the largest
treasure of renewable energy. All over the world, especially in our country most of the time in a
year sun provides a good exposure (see figure 1). The use of sun for lightning during day time and
heating in winter season is not a new concept. This was done from centuries. But due to increasing
energy problems World is shifting toward utilizing renewable energy resources.
1
Figure 2.1 Pakistan Direct Normal Solar Radiations Annual Figure.
2.2 Renewable Energy resources of Pakistan:
Figure 2.2 explains the renewable energy
share with global energy consumption which is almost 19 percent of the total. Biomass, biofuel,
hydropower, wind, solar and geothermal technologies are the major contributors of this share.
1
NREL ASSOSIATION with the help of USAID CORPORATION

8. Figure 2.2 Estimated Renewable Energy Share in Global Final Energy Consumption
(2011) [1]
Figure 2.3 Renewable power capacity
While in figure 2.3, growth trend for renewable technologies can be seen from 2000 till 2014. CSP
technology didn’t draw much growth in early years of 2000s but later it showed significant growth
as it is clear from the graph.

9. 3. Literature Review:
3.1Background Research:
Concentrating Solar Power technology is introduced during 18’s. Mr. Auguste Mouchout
is the first person that use the Parabolic trough technique to produce steam for steam engine in
1866. The first patent for solar collector is invented by Mr. Battaglia in Genoa, Italy in 1886. Later
on John Ericson developed many CSP units for the irrigation, refrigeration and locomotion.
3.2Early commercial adaption:
Solar Energy utilization techniques are not present research but scientists are working from
many years to utilize solar energy.
1897:
“Frank Shunam”, a US Engineer and pioneer of solar energy develop a small solar engine
which worked by reflecting solar energy on the boxes which are filled with fluid which has boiling
point less than water.
1912 - 1913:
Shuman built a first world’s largest Solar Thermal Power Station in Madi Egypt.
He used parabolic troughs to power a 45-52 engine that pumped more than 22,000 litres of water
per minute from the Nile River to adjacent cotton fields. [2]
3.3 Currently Working Plants based upon Parabolic trough collectors.
There are many plants which are working and contributing a lot of energy in the world’s
total power production such as
Table 3.1 List of Power Stations using Parabolic Trough Collectors. [3] [4]
3.4 Solar Radiations:
Sun irradiation can be described as the flux of energy that the earth receives from the sun.
This energy arrives as a set of waves at different frequencies, some of which are detectable by the
human eye and another part, such as infrared rays, cannot be detected by the human eye.
A classification of the types of irradiation can be made according to the way
an object receives the sun’s rays.
Sr. No Year of development
1 2014
2 2014
3 2014
4 2014 Solaben Power Plant ( Spanish)
Genesis Solar Energy project
Solana Generating Station
Capacity (MW)
200
250
250
354
Plant
California

10. 3.4.1 Direct radiation:
It is the unaltered radiation that comes directly from the sun without going through any
changes on its way. It is characterized by its projection of a defined shade of those objects that
intercept its path.
Figure 3.1 Components of Solar Radiation
3.4.2 Diffuse radiation:
Part of the sun irradiation that crosses the atmosphere is absorbed and reflected by clouds,
dust particles in the air, trees, mountains etc. As a consequence of this, this type of radiation goes
in all directions. It does not produce shades on objects. Horizontal surfaces receive it more than
vertical ones because they are exposed to the entire sky vault; whereas the vertical surfaces are
only exposed to half of it.
3.4.3 Reflexed radiation:
This is the radiation that is reflected by a surface. Its quantity depends on the surface’s
reflection coefficient.
3.4.4 Global radiation:
As its name indicates, this is the sum of the above mentioned radiations.
3.5 Solar Collectors:
A solar thermal collector is a collector to collect heat by absorbing sun light. A collector
is a device for converting the energy in solar radiation into a more useful or storable form. The
energy in sun light is in the form of electromagnetic radiation from the infrared to the ultraviolet
wavelength. The solar energy striking the Earth’s surface depends upon weather condition as well
as location and surface tilt angle but overall it’s average value is 1000 W/m2
with clear sky and
surface directly perpendicular to the sun rays.

11. 3.5.1 Current Solar Concentration Technologies:
a. Parabolic Trough
b. Fresnel Lenses
c. Parabolic Dish
d. Power Tower
Figure 3.2 Schematic Of Concentrating Solar Power Units
3.6 Parabolic Trough Technology:
3.6.1 Working Principle:
Parabolic trough-shaped mirror reflectors are used to concentrate sunlight on to
thermally efficient receiver tubes placed in the trough focal line. In these tubes a thermal transfer
fluid is circulated, such as synthetic thermal oil. Heated to approximately 400°C by the
concentrated sun’s rays, this oil is then pumped through a series of heat exchangers to produce
superheated steam. The steam is converted to electrical energy
in a conventional steam turbine generator.

12. Figure 3.3 Components and Concentration of rays at the focal point of Parabolic Trough
3.6.2 Suitable Materials for Collector:
To achieve the maximum collector efficiency, selection of most appropriate material
is very important. The material should posses
 High Reflectivity
 Low absorptivity
Table 3.2 Suitable Materials for collector. [5]
3.6.3 Suitable Materials for Absorber:
As for as the absorber materials are concerned, they should possess
 High absorptivity
 Low Reflectivity
 High Thermal Conductivity
Table 3.3 Suitable Materials for Absorber. [5]
Sr. No Matterial Desnsity Temperature
1 Steanless Steal 7.93 115
2 Glass Mirror 2500 120
3 Polished Aluminium 2.7 110
4 Silver Mirror Film 2100 100
5 Acrylic Mirrors 2400 85
Thermal Conductivity
1.05
16.2
215
1.15
1.1
Sr. No Matterial Desnsity Temperature
1 Aluminium Tube 2.65 125
2 Glass Tube 2500 120
3 Copper Tube 8920 90
4 Steanless Steel Tube 7.93 120
Thermal Conductivity
16.2
400
1.05
210

13. 3.6.4 Evacuated Tube Absorbers:
These this technology, the absorber is covered with evacuated glass tube. It has the
following benefits over the other choices
 The glass tube is transparent to solar short wave radiation but not to thermal long wave
radiation also glass is stronger than the alternative transparent plastic materials.
 Glass can hold vacuum better than any other material.
 The out gassing rate from a Bake-Pyrex glass is such that Pressure should be less than 0.1 N/m2
per 300 years which is 1012
times longer than a copper tube. [6]
 This technology is used to reduce convection losses.
 The vacuum also allows thermal expansions.
Figure 3.4 Configuration of Evacuated Receivers
3.6.5 Heat Transfer Fluids:
Parabolic trough solar collectors utilize a heat transfer fluid that flows through the
receiver to collect the solar thermal energy and transport it to the power block. The type of heat
transfer fluid used determines the operational temperature range of the solar field and thus the
maximum power cycle efficiency that can be obtained. In good solar climates, Parabolic trough
plants without thermal storage can produce an annual capacity factor of approximately 25%.
Table 3.4 Heat transfer fluids with application in solar parabolic trough fields. [7]
2 Mineraloil, e.g., Caloria
3 Water, pressurized, +glycol
4 Water/steam
5 Silicon oil
6 Nitrate salt
7 Ionic liquids
8 Air
Synthetic oil, e.g., Biphenyl-
diphenyloxide
13 – 395
Sr. No
1
–25 – ˃100
Temperature
Range (°C)
–10 – 300
Fluid
0 – ˃500
40 – 400
183 – ˃500
220 – 500
–275 – 416
High receiver pressure required and thick-walltubing
Odorless, nontoxic, expensive and flammable
High freezing temperature, high thermalstability and corrosive
Organic methyl-imidazole salts, go thermalproperties, very costly and no mass product
Low energy density, only specialIndustrialprocess heat applications
Relatively high application temperature and flammable
Relatively inexpensive and flammable
Only low-temperature Industrialprocess Heat applications
Properties

14. 3.6.6 Thermal Storage:
One of the potential advantages of parabolic trough technologies is the ability to store
solar thermal energy for use during non-solar periods. For the storage of heat salts Mostly
“Potassium Nitrate and Sodium Nitrate” having Melting points 200 °C. Adding thermal storage
allows the plant capacity factor to be increased from normal range which is 25% to 50% or more.
3.6.7 Optimum solar Flux Extraction:
The maximum solar flux is obtained we the solar ray strikes perpendicular to the
surface of solar collector. So, to gain the optimum flux extraction
 The parabolic trough should be due South facing.
 The slope angle of the parabolic trough should be equal to the latitude value of the
particular location.
3.6.8 Tracking System:
Tracking systems are required for collectors to follow the sun in order to
concentrate the direct solar radiation onto the small receiver area. High concentration ratio
collectors cannot work without a tracking system. Various forms of tracking mechanisms, varying
from simple to complex, have been proposed. They can be divided into two broad categories. One
is Mechanical and other one is Electrical/electronic systems. 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 that 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. The parabolic trough is single tracking
technology.
3.6.9 Parabolic trough power plant Layout:
Figure 3.5 Schematic of a Parabolic Trough power plant with a thermal storage syst

15. 4. Aims and Objectives:
The major task behind this research work is to increase the efficiency of the parabolic
trough collector. We adopted different techniques and methodologies for the completion of this
task.
Following sequence is adopted to
 3D Designing on Pro_E.
 Most appropriate materials for fabrication.
 Different selective surfaces for collector.
 Use of Evacuated Glass Tube for absorber.
 Experimentation by Hand layup method.

16. 5. Methodology:
5.1Calculations of Geometrical Parameter:
Based on two parameters of parabolic trough collector (PTC), the rim angle which
is  80r and width of collector it is possible to determine the aperture of parabola. [8]
2
)(
8
1
2
tan
f
a
f
a
r

 (1)
Above equation gives another way of mechanical design if we take two parameters, rim angle and
aperture of parabola according to the prototype requirement.

















 







 

2
tan
2
secln
2
tan
2
sec2 rrrr
fS (2)
This equation further proceeds to calculate the width of collector S based upon focal length value
obtained from the first equation.





 







 







 

2
tan
2
secln
2
tan
2
sec
2
tan2
rrrr
r
a
S
W (3)
This equation is the alternate way of calculation taking rim angle and collector width as selected
values.
2
tan4 r
aW
f

 (4)
Equation gives the value of focal length.
The absorber tube must have a sufficient diameter to permit a high intercept factor. The intercept
factor is the ratio of the total reflected radiations to the reflected radiations that hit the absorber
surface.
On the other hand, diameter should not be as large to have more thermal losses. For ease of our
calculations we assume intercept factor of value 1 means there are no slope errors or microscopic
errors on the collector surface. The necessary absorber diameter to reach an intercept factor of 1
depends upon the distance of the absorber tube from the collector surface and the solar beam angle.

17. Figure 5.1 Visualization of Solar Beam Angle
The distance between the collector and the absorber is different for the different points on the
collector surface and is maximum for mirror rim and the absorber. So we take the rim of the
parabola to determine the absorber diameter. [9]
Figure 5.2 Relationship between absorber diameter and rim angle
r
D
abs
a
d






 

sin
2
sin

(5)
Geometric concentration ration can be calculated by the following formula
o
a
d
W
C

 (6)
The optical efficiency is expressed by [10]
  costan1 fagro A (7)
Where θ is the angle of incidence. ϒ is the intercept factor and Af is the geometric factor.
In case of the normal incidence optical efficiency is reduced to
 agro  (8)

18. Table 5.1 Summary of PTC key features.
5.2Software Based Designing:
Based upon the above calculated Parameters as shown in Table 5.1, we
design the parabolic trough in Pro_E Wildfire 4.0.
Figure 5.3 3D Modeling in Pro_E
Description Dimensions
parabolic length (L) 127 cm
parabolic aperture (Wa) 63.50 cm
Focal distance (f) 19 cm
Aperture area (Aa) 0.805 m
2
Rim angle (ɸr) 80⁰
Inner diamiter of the reciever (di) 8 mm
Outer diameter of the reciever (do) 10 mm
Concentration ratio (C) 20.2
Optical efficiency 57%

19. Figure 5.4 Ground supports and trough supporting trusses
Figure 5.5 Cross-section of Evacuated annular tube

20. 5.3Experimentation:
Experimentation has been performed on a fabricated parabolic trough collector to
further enhance the efficiency of the unit to get max possible temperature rise. Different
coatings of high reflectivity like silver paint, aluminum silver sheet, aluminum foil and
specially mirrors have been used. To minimize convective losses, a thin cover sheet covering
all aperture area has been used. Moreover, an evacuated glass tube has been installed round the
absorber to further decrease the convective losses. Results of these different techniques has
been elaborated in next section in the form of tables and graphs. Parameters like tilt angle, day
time and air velocity have been considered seriously. All experiments were performed by hand
layup method.

21. 6. Results:
6.1Case-I
Aluminum trough and black absorber tube:
Figure 6.1 Experimentation with Aluminum trough and black absorber
Table 6.1 Experiment data for temperature rise in Case-I
6.2 Case-II
Silver coated collector and black absorber tube:
Figure 6.2 Experimentation with Silver coated collector and black absorber tube
°C
Time
Normal Water
Temperature
Ambient
Temperature
Experiment
Time Duration
Final Water
Temperature
°C
30 - 35
30 - 35
36
36
26
26
64
62
12:30 PM
2:00 PM
°C Minutes

22. Table 6.2 Experiment data for temperature rise in Case-II
6.3 Case-III
Aluminum foil and black absorber tube:
Figure 6.3 Experimentation with Aluminum foil trough and black absorber tube
Table 6.3 Experiment data for temperature rise in Case-III
30 - 35
30 - 35
60
58
38
36
26
24
1:00 PM
2:00 PM
Time
Ambient
Temperature
Normal Water
Temperature
Experiment
Time Duration
Final Water
Temperature
°C °C Minutes °C
2:30 PM 37 25 30 - 35 67
01::00 PM 38 26 30 - 35 68
Time
Ambient
Temperature
Normal Water
Temperature
Experiment
Time Duration
Final Water
Temperature
°C °C Minutes °C

23. 6.4 Case-IV
Aluminum Silver metal sheet and black absorber tube:
Figure 6.4 Experimentation with Aluminum Silver metal sheet collector and black absorber tube
Table 6.4 Experiment data for temperature rise in Case-IV
6.5 Case-V
Mirrors as reflecting surface and black absorber tube:
Figure 6.5 Experimentation with Aluminum Silver metal sheet and black absorber tube
12:20 PM
36 26 30 - 35 7501::00 PM
36 26 30 - 35 77
Time
Ambient
Temperature
Normal Water
Temperature
Experiment
Time Duration
Final Water
Temperature
°C °C Minutes °C

24. Table 6.5 Experiment data for temperature rise in Case-V
6.6Case-VI
Mirrors as reflecting surface and evacuated glass tube:
Figure 6.6 Experimentation with Mirrors as reflecting surface and evacuated glass tube
Table 6.6 Experiment data for temperature rise in Case-VI
12:15 PM 39 27 30 - 35 77
1:20 AM 37 26 30 - 35 78
Time
Ambient
Temperature
Normal Water
Temperature
Experiment
Time Duration
Final Water
Temperature
°C °C Minutes °C
2:15 PM 39 27 30 - 35 81
12:20 PM 39 27 30 - 35 81
Time
Ambient
Temperature
Normal Water
Temperature
Experiment
Time Duration
Final Water
Temperature
°C °C Minutes °C

25. Graph 6.1 Effectiveness of different techniques
6.7Case-VII
Case-VI without cover sheet:
Table 6.7 Experiment data for temperature rise in Case-VII
Graph 6.2 Graph depicting to effectiveness of Case-VI with different arrangements
0
10
20
30
40
50
60
70
80
90
Case-I Case-II Case-III Case-IV Case-V Case-VI
Temperature(°C)
Cases
Comperisonof different cases corresponding
to their Temperatures
Final Water
Temperature
°C
50
62
81
Case-VI without Cover sheet and evacuated tube
Case-VI without Cover sheet
Case-VI with Cover sheet
Different Arrangements
0
10
20
30
40
50
60
70
80
90
Case-VI without
Cover sheet and
evacuated tube
Case-VI without
Cover sheet
Case-VI with Cover
sheet
Temperature(°C)
Different Arrangements
Comperisonof different case-VI
arrangements correspondingto their
Temperatures

26. 7. Conclusion:
 As it is clear from the graph 6.1 by introducing the evacuated tube maximum temperature is
achieved as compared to the simple mat black coper tube. The reason is that we reduced the
forced convection loses which ultimately results the water temperature to increase.
 When we compare the parabolic trough with simple aluminum sheet and black copper absorber
with no cover sheet with the mirrored collector and evacuated absorber with a cover sheet the
temperature difference if final water after 30 minutes is 32 °C which is a significant figure.
This temperature difference is due to prevention in natural convection as well as forced
convection.
 Experimental results prevail that the overall parabolic trough efficiency strictly depends upon
the reflectivity of collector surface and absorptivity of receiver.
 By hand layup method we cannot make the evacuated tube perfectly evacuated so, due to this
minor fluctuation in readings may occur.
 By using aluminum silver metal sheets instead of mirrors as collector surface we get almost
same temperature in both cases. Aluminum silver metal sheets are cheaper than the mirrors. In
this way we can make this technology cost effective.
8. Future Perspectives:
 As the parabolic trough collectors are used for steam generation so they can be used in existing
steam power plants for the pre heating of the water and this leads to increase the efficiency of
power plant by reducing the fuel consumption.
 Introduction of thermal storage technology with nitrates (sodium, calcium, potassium, ….)
made this technology more and more profitable and it became direct competitors of
conventional power plants.
 In agriculture sector photovoltaic technology is used which has high initial and maintenance
cost. By replacing it with concentration based parabolic trough technology because it has pay
back potential. It’s initial cost is high but maintenance cost is very low.

27. 9. References
[1] Renewables 2013, Global Status Report, Renewable Energy Policy Network for the 21
Century.
[2] Smith, Zachary Alden; Taylor, Katrina D., Renewable And Alternative Energy Resources,
2008, p. 174..
[3] "Concentrating Solar Power Projects in the United States," 17 February 2014. [Online].
Available: NREL.gov.
[4] "Concentrating Solar Power Projects in Spain," 17 February 2014. [Online]. Available:
NREL.gov.
[5] Sri P. Mohana Reddy, Pathi Venkataramaiah and Devuru Vishnu Vardhan Reddy,
"Selection of Best Materials and Parametric Optimization of Solar Parabolic Collector
Using Fuzzy Logic," 26 October 2014.
[6] Weir, John Twidell and Tony, Renewable Energy Resources, Second ed., London: 1986, p.
137.
[7] David Kearney National Renewable Energy Laboratory1617 Cole Blvd., Golden, CO,
"Advances in Parabolic Trough Solar Power Technology".
[8] A. Gama, C. Larbes, F. Yettou and B. Adouane, ""Design and realization of a novel sun
tracking system with absorber displacement for parabolic trough collectors"," Renewable
and sustain energy, p. 03, May 23, 2013.
[9] Matthias Gunther (Intitute for Electrical Engineering, Rotational energy conversion,
University of Kassel, Wilhelmshoher Alee 73, 34121 Kassel), "Advanced CSP Teaching
Materials Chapter 2 "Solar Radiation"".
[10] Yassine Denagh , Ilyes Bordja, Yassine kbar and Hocine Bensoussa, "Adesign method of
an S-curved parabolic trough collector absorber with a three-dimentional heat flux density
contribution," p. 10, July 23, 2013.
[11] Pilkington Solar International GmbH, 1996,Status Report on Solar Thermal Power Plants,
ISBN 3-9804901-0-6, Ko ¨ln, Germany..