1. Prof (Dr.) A. G. Mohod
Head
Deptt. of Agricultural Engineering
College of Agricultural, Dapoli
Dr. Balasaheb Sawant Konkan Krishi Vidyapeeth, Dapoli-415712
Dr.A.G.Mohod, DBSKKV, Dapoli : Solar Energy Collection and Application 1
Solar Energy Collection and Applications
Sun and its power as renewable energy source
Collection of Solar energy
Solar Collectors and their working
Collectors and their temperature ranges
Applications of solar energy
2. Dr.A.G.Mohod, DBSKKV, Dapoli : Solar Energy Collection and Application 2
The most basic processes supporting life on earth, such as photosynthesis and
the rain cycle, are driven by solar energy.
Energy from the sun in the form of solar radiation supports almost all life on
earth via photosynthesis and drives the earth’s climate and weather.
The sun generates its energy by nuclear fusion of hydrogen nuclei to helium
The energy delivered to the earth surface in the form of radiations is termed as
“solar energy”
It’s diameter is 1.39 X 104 Km. while that of the earth is 1.27 X 104 K.
The earth distance between the two is 1.5 X 108 km.
The average surface temperature of sun is 5762 0 K.
3. Dr.A.G.Mohod, DBSKKV, Dapoli : Solar Energy Collection and Application 3
The sun’s total energy output is 3.8 x 10 20 MW.
The earth receives only a tiny fraction of the total radiation equal to 1.710 14 kW
84 min of solar radiation falling on earth is sufficient to the world demand for one year.
The radiation wavelength that is important to solar energy applications is 0.15 to 3.0 μm.
The wavelengths in the visible region lie between 0.38 and 0.72 μ m.
The amount of solar energy per unit time, at the mean distance of the earth from the sun,
received on a unit area of a surface normal to the sun outside the atmosphere is called the solar
constant, Gsc.
The average value of solar constant is 1353 W/m2.
The solar heat reaching the earth’s surface is reduced below Gsc as it is scattered, reflected
back out into space, and absorbed by the atmosphere.
The scattered and non directional radiation reaches the earth’s surface from the entire sky is
called the diffuse radiation.
The solar heat that comes directly through the atmosphere is termed direct or beam radiation.
Solar Radiations on earth surface
4. Dr.A.G.Mohod, DBSKKV, Dapoli : Solar Energy Collection and Application 4
Advantages: Reliable, Secure, Clean, Decentralized, Round the year,
No DT loss, Comparative Cost, Scalable, Low gestation period,
Employability
The solar heat at any point on earth depends on
1. The ozone layer thickness
2. The distance traveled through the atmosphere
to reach that point
3. The amount of haze in the air
4. The extent of the cloud cover.
The major limitations of the solar energy are
1. It is intermittent in nature (Only day time)
2. Fluctuating in nature (Hours to hours, day to day, seasons to season )
3. Very low intensity (450-650 w/m2)
4. Larger area required
5. Dr.A.G.Mohod, DBSKKV, Dapoli : Solar Energy Collection and Application 5
Solar Energy Collection and types of collectors
The solar energy cannot be use for end use application directly. It required
intermediate device called as solar energy collector
- to effectively collect the radiation
- to convert solar radiation in to heat
- to transfer the stored heat to the medium
- to prevent the losses from the device.
The solar collector is a device used to absorb the incident radiations, convert the
radiation in to heat and transfer the heat to the medium (water or air) for end use
application.
There are basically two types of solar collectors:
1. Non-concentrating or stationary
2. Concentrating.
7. Dr.A.G.Mohod, DBSKKV, Dapoli : Solar Energy Collection and Application 7
Motion Collector type Absorber type Concentration ratio Temp. range (°C)
Stationary
Flat-plate collector
(FPC)
Flat 1 30–80
Evacuated tube
collector (ETC)
Flat 1 50–200
Compound
parabolic
collector (CPC)
Tubular 1–5 60–240
Single-axis tracking
5–15 60–300
Linear Fresnel
reflector (LFR)
Tubular 10–40 60–250
Cylindrical trough
collector (CTC)
Tubular 15–50 60–300
Parabolic trough
collector (PTC)
Tubular 10–85 60–400
Two-axis tracking
Parabolic dish
reflector (PDR)
Point 600–2000 100–1500
Heliostat field
collector (HFC)
Point 300–1500 150–2000
Concentration ratio is defined as the aperture area divided by the receiver/absorber area of the collector.
Type of solar collectors with temperature range
8. Dr.A.G.Mohod, DBSKKV, Dapoli : Solar Energy Collection and Application 8
Flat Plate Collector
A basic flat plate collector is the simplest and most widely used means to convert the
sun's radiation into useful heat for meeting essential energy requirement
COMPONENTS
• Absorber plate ( black painted metal)
• Passage for medium ( Copper tubes)
• Insulation ( Glass wool)
• Glazing ( Glass cover)
• Casing ( Aluminium)
• Worked on the principle of natural
green house effect.
• Flat plate collectors are classified as
liquid flat plate collector and air flat
plate collector.
• Use to achieve temp. upto 100 0C
• Used for cooking, water heating,
drying, desalination,
9. Dr.A.G.Mohod, DBSKKV, Dapoli : Solar Energy Collection and Application 9
Water systems Air systems
Types of Flat plate Collector
10. Dr.A.G.Mohod, DBSKKV, Dapoli : Solar Energy Collection and Application 10
Evacuated Tube Collector
To overcome the problems of simple flat-plate solar collectors that is reduction of
performance in unfavorable conditions during cold, cloudy, and windy days, evacuated
tube collectors are developed.
• These solar collectors consist of a
heat pipe inside a vacuum-sealed
tube,
• The vacuum envelope reduces
convection and conduction losses,
so the collectors can operate at
higher temperatures than flat-
plate collectors.
Evacuated tube collectors use liquid-vapor phase change materials to transfer
heat at high efficiency. This self-limiting temperature control is a unique feature
of the evacuated heat pipe collector.
11. Dr.A.G.Mohod, DBSKKV, Dapoli : Solar Energy Collection and Application 11
Concentrating Collectors
• Energy delivery temperatures increased if area of heat loss decreases.
• High temperatures can be reached if a large amount of solar radiation is
concentrated on a small collection area.
All of these are imaging concentrators which allow relatively high
concentration temperatures: about 400 oC for parabolic troughs, up to 650 oC
for Stirling dishes, and above 1000 oC for solar power towers.
12. Dr.A.G.Mohod, DBSKKV, Dapoli : Solar Energy Collection and Application 12
Concentrating collector’s exhibit certain advantages are as follows:
1. The working fluid can achieve higher temperatures in a concentrator system
than a flat-plate system.
2. The thermal efficiency is greater because of the small heat loss area relative to
the receiver area.
3. Reflecting surfaces require less material and are structurally simpler.
4. Owing to the relatively small area of receiver per unit of collected solar
energy.
Their disadvantages are:
1. Concentrator systems collect little diffuse radiation, depending on the
concentration ratio.
2. Some form of tracking system is required to enable the collector to follow the
sun.
3. Solar reflecting surfaces may lose their reflectance and require periodic
cleaning.
13. Dr.A.G.Mohod, DBSKKV, Dapoli : Solar Energy Collection and Application 13
Thermal
• Temperature
wise (L/M/H
temp.)
• Direct/Indirect
use
Electricity
SPV
• Direct power-
DC/AC
• Power plants
Stand Alone
Off Grid
On Grid
S/M/L capacity
Active
Passive
Stand Alone
Hybrid
S.N. Types of application and uses Types of conversion device
1 Low temperature applications (40 – 100 OC)
water heating drying, cooking and distillation.
Use of flat plate collectors
2 Medium temperature applications (100 – 350 OC)
heating, drying, steaming, industrial process heat and
frying / baking / roasting
Use of concentrating parabolic collectors,
evacuated tube collectors
3 High temperature application (350 OC to more)
electricity generation and industrial process heat.
Use of highly concentrating reflector system,
point focusing collector and step reflector.
Application and system for use of solar energy
14. Dr.A.G.Mohod, DBSKKV, Dapoli : Solar Energy Collection and Application 14
Different applications of solar energy for
Thermal applications
1. Food Cooking – Solar cookers
2. Hot water generation- Solar water Heaters
3. Drying of agriculture and food – Solar dryers
4. Desalination of water- Solar still (Distillate) unit
5. Pool Heating – Solar pond
6. Space Heating and Cooling- Solar heater/ Solar refrigerator
7. Solar thermal power generation
Solar Energy for Electricity
(SPV-Solar Photo-Voltaic System)
Water Pumping
Home Lighting
16. Dr.A.G.Mohod, DBSKKV, Dapoli : Solar Energy Collection and Application 16
Quick review
Sun and its power as renewable energy source
Collection of Solar energy
Solar Collectors and their working
Collectors and their temperature ranges
Applications of solar energy
Thank you for listening