Renewable energy comes from resources that are naturally replenished such as sunlight, wind, rain, tides, waves and geothermal heat. It is used in four areas: electricity generation, heating, motor fuels, and rural energy services. Solar thermal systems collect and concentrate sunlight to produce high temperature heat for generating electricity. They use solar collectors like parabolic troughs and central towers to absorb sunlight and transfer the heat to a working fluid. The heated fluid is then used to power steam turbines or for other applications like solar water and space heating. While solar thermal is a clean renewable source, it also has limitations such as intermittency, high initial costs, and land use requirements.

1. Renewable energy
Renewable energy is generally defined as energy
that comes from resources which are naturally
replenished on a human timescale such as
sunlight, wind, rain, tides, waves and geothermal
heat. Renewable energy replaces conventional fuels
generation, hot
and rural (off-
in four distinct areas: electricity
water/space heating, motor fuels,
grid) energy services.

2. Renewable Energy Sources
– Renewable Energy Sources
• Radiant solar energy
– Solar heating (passive and active), solar power plants, photovoltaic
cells
• Biomass energy
– Direct: combustion of biomass
– Indirect: chemical conversion to bio fuel
• Wind energy
• Hydro energy
• Geothermal energy
– Power plants, direct use, heat pumps
• Ocean energy
– Tidal; salinity-driven

3. Hydro Energy
• Advantages
– Cheap to operate
• Long life and lower operating costs than all other power plants
– Renewable
– High yield
• Lower energy cost than any other method
– Pretty plentiful
• Some countries depend almost entirely on it
– Not intermittent (if reservoir is large enough)
– Reservoirs have multiple uses
• Flood control, drinking water, aquaculture, recreation
– Less air pollution than fossil fuel combustion

4. Hydro Energy
• Disadvantages:
– Human population displacement
– More significant breeding ground for disease
– Reduces availability of water downstream
– Ecosystem impacts
• Barriers to migrating fish
• Loss of biodiversity both upstream and downstream
• Coastal erosion
• Reduces nutrient flow (dissolved and particulate)
– Water pollution problems
• Low dissolved oxygen (DO)
• Increased H2S toxicity; other DO-related problems
• Siltation a big problem (also shortens dam life)
– Air pollution
• Actually may be a significant source of GHGs (CH4, N2O, CO2)
– Decommissioning is a big problem
• The Size Issue
–
–
Many (most) of the above problems are significantly worse for larger dams
However, small dams have shorter lifetimes, less capacity, and are more
intermittent

5. Wind Energy
• Advantages
– High net energy yield
– Renewable and free
– Very clean source of energy
• No pollution (air or water) during operation
– Long operating life
– Low operating/maintenance costs
– Can be quickly built; not too expensive
– Now almost competitive with hydro and fossil fuels
– Land can be used for other purposes
• Can combine wind and agricultural farms

6. Wind Energy
• Disadvantages
– Energy storage issues
• An intermittent source of energy; need backup (eg stored energy)
for low-wind days
• Or must be connected to the electrical grid
– Only practical in areas that are windy enough
– Visual pollution
– Danger to birds
• New (slow turning) designs largely eliminate this problem
– Low energy density of wind
• Must use large areas of land

7. Biomass Energy
• What is it?
–
–
– Biomass energy is the use of living and recently dead biological material as
an energy source
Ultimately dependent on the capture of solar energy and conversion to a
chemical (carbohydrate) fuel
Theoretically it is a carbon neutral and renewable source of energy
• How it works?
– Traditional: forest management, using wood as fuel
– Use of biodegradable waste
• Examples: manure, crop residue, sewage, municipal solid waste
– Recent interest in agricultural production of energy crops
•
•
•
•
Should be high yield and low maintenance
Examples: corn, sugarcane, switchgrass, hemp, willow, palm oil, rapeseed, and
many others
Does not have to be a food crop
Recent interest in bioengineered (GM) plants as fuel sources
– Production of a liquid or gaseous biofuel
• Biogas due to the breakdown of biomass in the absence of O2
– Includes capture of landfill methane
• Bioethanol from fermentation, often from corn. Cellulosic bioethanol is usually
from a grass (switchgrass)
• Biodiesel from rapeseed and other sources

8. Biomass Energy
• Carbon neutral
– CO2ultimately released in energy generation is recently captured and so ideally
does not change total atmospheric levels
– Carbon leaks can result in a net increase in CO2 levels
– Sequestration in soil can result in a net decrease in CO2 levels

9. Biomass Energy
•
•
Advantages
– Versatile
– Renewable
– No net CO2emissions (ideally)
– Emits less SO2and NOxthan fossil fuels
Disadvantages
– Low energy density/yield
• In some cases (eg, corn-derived bioethanol) may yield no net energy
– Land conversion
•
•
Biodiversity loss
Possible decrease in agricultural food productivity
– Usual problems associated with intensive agriculture
•
•
•
•
Nutrient pollution
Soil depletion
Soil erosion
Other water pollution problems

10. Geothermal Energy
•
•
•
How it works
– Geothermal power plants
• Use earth’s heat to power steam turbines
– Geothermal direct use
• Use hot springs (etc) as heat source
– Geothermal heat pumps
Advantages
– Renewable
– Easy to exploit in some cases
– CO2production less than with fossil fuels
– High net energy yield
Disadvantages
– Not available everywhere
– H2S pollution
– Produces some water pollution (somewhat similar to mining)

11. Radiant Solar Energy
• How it works
– Solar power plants
• Steam produced to turn turbine
– Solar heating
• Active and passive systems
– Photovoltaic cells
• “Solar batteries” use special semiconductors
• Advantages
–
–
–
Renewable and free
High energy yield
A very clean source of energy
• No air/water pollution during operation
– Low operating costs
• Will pay for themselves over time
• Disadvantages
– Intermittent source
• Energy storage issues
– Low energy density
• Requires pretty much land

12. Solar
ther
mal
syste
m
T HE INSTISTUTE OF
SCIENCE
COURSE CODE; -
MPHSEC 2T
S U N I L
DHANA
RE MI LI

13. TOPI
CS
•Introduction to solar thermal
system
•Working of solar thermal
system
•Solar collector
•Type of solar collector
•Solar water heater
•Solar heating and cooling
•Solar refrigeration and air
conditioning
•Solar-
cookers,dryers,distillation

14. Introducti
on:
Sun is the most abundant,reliable and renewable source of
energy.
This energy can be
harnessed by two
way: 1).Solar
thermal 2).Solar
photovoltaic
Solar thermal energy is the advance techniques which
produces maximum efficient
enrgy compare to photovoltaic cell.

15. Ye
ar
Descript
ion
186
6
Auguste Mouchout used a parabolic trough to produce steam
for the first solar steam engine
188
6
First patent for a solar collector was obtained by the Italian
Alessandro Battaglia in Genoa, Italy
191
3
Frank Shuman finished a 55 HP parabolic solar thermal energy
station in Maadi, Egypt for irrigation
192
9
First solar-power system using a mirror dish was built by
American Scientist Dr. R.H.
Goddard.
196
8
First concentrated-solar plant, which entered into operation in
Sant'Ilario, near Genoa, Italy
198
4
Parabolic-trough technology of the Solar Energy Generating
Systems (SEGS) begun its
combined capacity354 MW.
201
4
World's largest solar thermal plant (392 MW) achieves
commercial operation in Ivanpah Califoma, USA
Histo
ry

16. Solar thermal
s
ystem:
•Solar thermal power (electricity)
generation systems collect and
concentrate sunlight to produce the
high temperature heat needed to
generate electricity.
•Solar thermal collectors can absorb
nearly the entire solar spectrum.
•Thus concentrated solar power (CSP)
technology is more efficient than
photovoltaic solar cells.

17. Solar
collector:
• Solar power has low density
per unit area (1 kW/sq. m. to
0.1 kW/sq. m.) hence it is to be
collected by covering large
groundarea.
• Solar thermal collector essentially
forms thefirst
unit in a solar thermalsystem.
• It absorbs solar energy as
heat and then transfers it to
heat transport fluidefficiently.
• The heat transport fluid delivers
this heat to thermal storage tank

18. Concentrating solar
technologies
Low temperature
(<100 C)
Medium temperature-line
focusing(<400 C)
High temperature –point
focusing(>400 C)
1. flat plate
collector
2. solar
chimney
3. solar
pond
1. Parab
olic
trough
collect
or(PT
C)
1. Central tower
collector
2. Parabolic dish
collector
Classification of solar collector on basis of their concentrating temperature

19. 1.Low temperature collectors
(<100"C):
Flat plate solar
collector
Flat plate collector is basically a
black surface
that is placed at a convenient path
of a sun
The sun heats a dark flat surface,
and then the energy is transferred
to water, air, or other fluid for
further use•
These are used in domestic house
hold purpose like water heating &
space heating etc.They operate in
the temperature range from 30 to
80 "C.

20. 2. Medium temperature
collectors– Line focusing
(<400 °C):
Parabolic trough collector
(PTC):
•Parabolic trough is the linear-focus
collector.
•It consists of a cylindrically curved
parabolic mirror, which reflects the
sunlight onto a tubular receiver
positioned in the focus line of the
parabola..
•The tubular receiver contains the
fluid that absorbs heat and transfers
it via circulation to the boiler or
another device to produce steam.
•PTCS are made by simple bending a
sheet of reflective or highly polished

21. 3. High temperature
collectors– Point
focusing (>400 "C):
Central tower
collector:
•In this system multiple tracking mirrors
(heliostats) positioned in the field around
central receiver installed on a tower
•These systems are capable of reaching
of much higher levels of concentration
than linear systems
•Typically 80 to 95% of the reflected energy
is absorbed into the working fluid which is
pumped up into the receiver
•The working fluid is used as heat
source to produce steam and
convert it to electricity•
• The generated thermal energy can be
stored in amolten
salt storage

22. Solar water
heater
A Solar Water Heater is a device
which provides hot water for bathing,
washing, cleaning, etc. using solar
energy.
It is generally installed at the terrace
or where suntight is availableA tilted
flat plate solar collector with water as
heat transfer fluid is used.

23. Working of solar
water heater
• A thermally insulated hot water storage tank is mounted above the
collector.
•The heated water of the collector rises up to the hot water tank
and replaces an equal quantity of cold water, which enters the
collector.
• The cycle repeats, resulting in all the water of the hot water tank
getting heated up.
•When hot water is taken out from hot water outlet, the same is
replaced by cold water from cold-water make up tank fixed above
the hot water tank. The scheme is known as passive heating
scheme,
•When the collector is fixed above the level of hot water tank, a
pump is required to induce circulation of water in the loop and the

24. Solar heating and cooling
technology: solar
heating
•Solar heating and cooling technology
receive the thermal energy from sun
and utilize this energy to provide hot
water, space heating and pool heating
for residential, commercial and
industrial applications.
•These applications of SHCS reduce
the dependency on electricity or
natural fuels.
• The main function of solar system is to
convert sun
light into heat.
•The primary requirement of SHCS is to

25. Active and passive Solar
heating:
ACTIVE SOLAR HEATING:
• This system can be used as
commercial hot water as well
as space heat.
• A space heat application
involves some additional
connecting hardware for
space heat distribution
system.
• Active solar heating system
involve following major
components:Collectors to
absorb energy,Circulation
system,Storage tank,Backup
PASSIVE SOLAR HEATING:
•Passive solar heating is
the least costly technique
to heat home space.
•The main aim of this system is to
kept out heat in summer and kept
in heat in winter from sun light.
•Passive solar heating also
depends on ventilation or
windows provided in buildings
or houses.

26. Solar
cooling
Solar cooling is a technology that converts sun light
heat energy into useful cooling of buildings. The
process works by using solar heat collecting and
supplied this heat to the thermal cooling system, to
generate chilled water.

27. Solar air conditioning and
refrigeration:
Solar refrigeration
•The principle of absorption
refrigeration was first
demonstrated by Faraday in 1825.
Thus, this is one of the oldest
cycles for producing refrigeration
effect, which differs fundamentally
from the conventional vapour
compression cycle in the method
for compressing the refrigerant.
•Refrigerator which run on
electricity provided by solar
energy is known as solar

28. Working of solar
refrigerator
•In absorption cycle cooling systems two working fluids: a refrigerant and an absorbent-
refrigerant solution are used.
•The absorbent-refrigeration combination is so chosen that the absorbent have high affinity
for the refrigerant and at the same temperature, vapour pressure of the refrigerant is higher
than that of absorbent.
•The absorbent cooling is based on the principle that the refrigerant can be bound by a
liquid or solid solvent, known as absorbent to release heat during absorption, while it
absorbs heat during evaporation (and thus producing cooling effect).
•Though large number of refrigerant-absorbent combination is possible, the two most
common and commercially tried combinations are: LiBr-water (LiBr as absorbent and
water as 176 Non-Conventional Energy Resources refrigerant) and aqua-ammonia
(water as absorbent and ammonia as refrigerant).
•In the former the absorbent is a solid (a salt) whereas in the later it is a liquid.
•The performance of a cooling cycle is judged from its COP (coefficient of performance),
which is defined as the ratio of

29. Solar air conditioning and
refrigeration:
Solar air conditioning:
•Air-conditioning is one of the
majorconsumers of electrical energy.
•The demand can be expected to increase
because of changing working times,
increased comfort expectations and global
warming.
•Solar air-conditioning might be a way to
reduce the demand for electricity.
•Process of converting solar thermal energy
(heat) into
conditioned

30. Conventional vs solar air
conditioning
CONVENTIONAL AIR
CONDITIONING
•When a liquid gas changes its
state, it takes or extract heat.
•At lower pressure, state changes
at lower temp.
•Extraction of heat means cooling.
•Gas gets compressed when heated.
•Gaseous refrigerant compressed
and then heated up in the solar
panel up to 90°C.
SOLAR AIR CONDITIONING
•In this system, water is used as
the refrigerant while lithium
bromide (Li Br)/ammonia is
used as the absorbent
•In the absorber, the lithium
bromide absorbs the water
refrigerant, creating a solution of
water and lithium bromide
•Lithium bromide has great affinity
for water vapour, however, when
the water. lithium bromide solution
is formed, they are not completely
soluble with each other

31. Advantage and
Disdvantages
ADVANTA
GES
There will be no fuel cost as the power
plant runs by sun energy
It doesn't cause pollution and global warming
effects
It uses existing equipment like solar thermal
mirrors, turbines etc.
Can store energy using molten salts instead of
using batteries
Uses less space than photovoltaics
for same energy generation output
Running costs of solar thermal are cheaper
than coal or gas plants
DISADVANTAGES
The initial capital costs for solar thermal is
large
Uses lot of water which is major problem
in desert areas
Usage of massive arrays of mirrors
impacts thewildlife species
These plants can be installed only in
places whichhave high amount of solar
radiation
Solar thermal can't be installed in
residentialarea
Build time would be longer than other
forms ofenergy generation

32. THANK
YOU