Solar Thermal Energy
• Solar thermal energy (STE) is a form of energy and a technology for harnessing
solar energy to generate thermal energy or electrical energy.
• Solar energy can be utilized by using both concentrating and non concentrating
solar collectors. Concentrating collectors can be classified in major three types:
• We are using Solar Parabolic dish collector in our project due to its high efficiency
than other two types.
Comparison Of Solar Concentrating
Parabolic Trough Dish / Engine Power tower
Size 30- 320 MW 5-25 KW 10-200MW
390 ºC 750 ºC 565 ºC
Peak efficiency 20 % 29.4% 23%
Low High Medium
Hybrid Design Yes Yes Yes
Annual Efficiency 11-16% 12-25% 7-20%
Experimental study of a parabolic solar concentrator by A.R.E.i Ouederni,
AW Dashmani ,F Astri ,M ben Salah and S ben Nasarallah. In the
experimental conditioned the temperature reaches an average value of 380 0C after
23 min which represents the heating time of the receiver.
Study on design of molten salt solar receivers for beam-down solar
concentrator. H. Hasuike, Y. Yoshizawa, A. Suzuki. Solar Energy: 2006,
(i) The Solar Hybrid Fuel Project of Japan aimed to develop molten salt solar
receivers with solar concentrators.
(ii) The working fluid temperatures reached around 580°C and the solar cavity
receiver designs were rated at an efficiency of 90% with thermal output of 100 MWth.
A solar concentrating photovoltaic / thermal collector Joseph Sydney
Coventry June 2004 for the degree of Doctor of Philosophy at the Australian
• This thesis discusses aspects of a novel solar concentrating photovoltaic / thermal
(PV/T)Collector that has been designed to produce both electricity and hot water.
Solar radiation studies at Karachi, Pakistan by Firoz Ahmed, Department of
Physics university of Karachi.
• The city of Karachi, on the average receives about 3,000 hours per year and nearly
8.3 hours per day, of bright useable sunshine.
• Karachi being a coastal station has average relative humidity, greater than 65 %
throughout the year. The exception months being July -August when the average
relative humidity is high as 80 to 90 %.
• The global solar radiation data Pakistan Meteorological Department , Quetta of the
last 25 years gives an annual total 7000 MJm-2d-1 on the monthly average basis.
Design and development of a parabolic dish solar water heater by Ibrahim Ladan
Mohammed. Mechanical engineering Department, college of Engineering Kaduna
Polytechnic, Kaduna, Nigeria.
• The design and development of a parabolic dish solar water heater for domestic
hot water application (up to 100°C ) is described.
• The heater is to provide 40 litres of hot water a day for a family of four.
• Thermal efficiencies of 52% - 56% were obtained.
Design and Study of Portable Solar Dish Concentrator by Fareed .M.Mohamed,
• The parabolic concentrator has high sun light reflectivity (up to 76%).
• The high reflectivity of solar radiation increases water outlet temperature in
• Furthermore using designed –sun light tracking system increased the operation
efficiency to 30 %.
• Design and Fabrication of laboratory scale dish type solar concentrator.
• Study and Performance of dish type concentrator to investigate the effect of
the following factors for its performance.
a) Solar Insolation
b) Concentration ratio
c) To analyze the quality of steam to its potential for power generation.
• ISC is energy from the sun per unit area, per unit time receive on a unit area
of surface perpendicular to the radiation in space, at the earth’s mean
distance from the sun. In 1971 NASA weighted average value of Solar
Constant is Isc= 1353 W/m2
Geometry of Paraboloid
• The equation of Paraboloid
• In cylindrical coordinate
• Depth was calculated from
• The surface area of parabola
• Focal length was calculated from
• CRG =
• In glass type solar concentrator
reflection and refraction both
occurs, when light intersect with
soda-lime window glass it is
reflected 8% assuming no
• ρ+α+τ =1
• τ = 1- 0.08
τ = 0.92 = 92%
• The refractive index of glass is
Reflectivity of silver is 97.5%
• Optical or Collector efficiency
• Thermal energy produced by the solar collector is
Qabs = Qin – Qloss
• Heat transfer
Qabs = Aa.ρs.m.αr. τc S.Ia
ρs.m is specular reflectance of concentrator,
τc is Transmittance of concentrator,
S is shading factor of receiver,
αr is absorbance of the receiver.
ρs.m.αr. τc are the material dependent parameters these are remain constant.
Receiving Diameter 0.2032m
Effective area 0.068m2
Specific heat capacity of
Thermal Conductivity 386W/mK
Internal Volume 600cm3
External Volume 788cm3
Specific heat capacity of
Thermal coefficient of
Effects of solar concentration
• Concentration Ratio increases thermal efficiency of
• At different concentration ratio desired temperature
can be achieved.
• Higher concentration ratio takes minimum / less time
for steam production.
• Concentration ratio rises the pressure of steam.
• Geometric concentrating ratio
• The testing is performed at different concentrating ratio by using 1, 2 and 3
• Concentrating Ratio: 10.38
• Concentrating Ratio: 20.76
• Concentrating Ratio: 31.15
• Proper clothing should be worn.
• Avoid loose clothing and jewelry.
• Protective equipment must be worn when necessary (i.e.: hard hats, ear
plugs, goggles, gloves, safety shoes, etc.).
• Always covered hot receiver with insulation
• Don’t touch receiver from bottom side without gloves.
• Move Concentrator with Care.
• Don’t place concentrating mirror Adjacent ?
• Notice Temperature and pressure gauge reading time to time when system
is in running condition.
• In this project different modification could be done.
• Our project based on Batch flow system it could be change in to continuous
• Steam could be superheated by placing a super heater.
• Molten salt is also used in Receiver or super heater.
• Tracking mechanism could be placed in concentrators.