Different forms and source of Energy.....

1. ME-181
Introduction to Mechanical
Engineering
LEVEL-1, TERM-I
Adib Bin Rashid
Capt
Instructor Class C
Mechanical Engineering Department

2. Adib Bin Rashid
Capt
Instructor Class C
Mechanical Engineering Department

3. Energy engineering
 Energy engineering or Energy systems is a broad field
of engineering dealing with energy efficiency, energy services, facility
management, plant engineering, environmental compliance and alternative
energy technologies.

4. Mechanical Energy:
•Defined as energy which can be used to raise a weight.
•Can be easily and efficiently converted into other energy forms.
Electrical Energy:
•Defined as that class of energy associated with the flow or
accumulation of electrons.
•Large quantities of electrical energy are transferred over long
distances with the use of high-voltage transmission lines.
•Can be converted into other energy forms.

5. Electromagnetic Energy:
•Defined as that form of energy associated with electromagnetic
radiation.
•Extensively employed in nuclear energy study.
Chemical Energy:
•Defined as energy that is released as the result of electron interactions
in which
two or more atoms and/or molecules combine to produce a more stable
chemical compound.
•Commonly reported in the units of energy per unit mass or “mole” of
fuel reactant

6. Sources of energy :-
There are two main sources of energy. They are
conventional and non conventional sources of
energy.
i) Conventional sources of energy :- are wood,
flowing water and fossil fuels (coal, petroleum,
natural gas).
ii) Non conventional sources of energy :- are solar
energy, wind energy, biomass energy, ocean energy
(tidal energy, wave energy, ocean thermal energy),
geothermal energy, nuclear energy etc.
Some sources of energy are renewable like sun, wind,
flowing water, ocean, wood, biomass etc.
Some sources of energy are non renewable like coal,
petroleum and natural gas.

7. Conventional sources of
energy :-
Fossil fuels :-
are fuels formed inside the earth from the remains of plants and
animals after millions of years. The fossil fuels are coal, petroleum
and natural gas. Fossil fuels are non renewable sources of energy
so they should be conserved and used judiciously.
Disadvantages of fossil fuels :-
i) Burning of fossil fuels release gases and harmful particles which
causes air pollution.
ii) Burning of fossil fuels release acidic oxides of sulphur and nitrogen
which causes acid rain which is harmful for living organisms,
affects soil and water, causes damage to buildings, corrosion of
metals etc.
iii) Burning of fossil fuels release a large amount of carbon dioxide gas
which increases the temperature of the atmosphere and causes
global warming (green house effect).

8. Fossil Fuels:
Fossil Fuels are formed from Living things millions of years ago.
They are Hydrocarbons and are Finite Fuels ie. They will run
out in the future and cannot be regenerated. There are three
main Fossil Fuels:
Coal, Oil and Gas
Oil: This was
formed by dead
sea creatures
falling to the sea-
bed where they
were subjected to
chemical change
by Bacteria.
Coal: This was
formed by the
decay of
Vegetation which
was subjected to
heat and pressure
over a very long
period of time.
Gas was formed
in much the
same way as Oil.
It is often
collected when
drilling for Oil.

9. Classification of Fuel
 Fuels may be classified into the following
general terms:
1. Solid Fuel
2. Liquid Fuels
3. Gaseous Fuel
Each of these fuels may be subdivided into the
following categories-
1. Natural Fuels
2. Prepared Fuels

10. Solid Fuel
 Wood: At one time it was an extensively used
fuel. It consists of mainly carbon and hydrogen.
 Peat: It is a spongy humid substance and
contains about 30% water. It has to be dried
before use. It is the first stage in the formation
of coal.
 Lignite or brown coal: It is the next stage of
peat in the coal formation and an intermediate
variety between bituminous coal and peat. It
contains nearly 40% moisture and 60% of
carbon.

11. Solid Fuel
 Bituminous Coal: It represents the next
stage of lignite in the coal formation and
contains very little moisture(4-6%) and 75 to
90% of carbon.
 Anthracite Coal: It represents the final
stage of coal formation and contains 90% or
more carbon.

12. Solid Fuel
 Wood Charcoal: It is made by heating wood
with a limited supply of air to a temperature
not less than 280˚C.
 Briquetted Coal: It is produced from finely
ground coal by moulding under pressure
with or without a binding material.
 Pulverised Coal: The low grade coal with
high ash content is powdered to produce
pulverised coal.

13. Coal composition and rank:
 All of the fossil fuels are produced from the fossilization
of carbohydrate compounds.
 Coal, the most abundant fossil fuel, is thought to be
fossilized vegetation.
 It is estimated that at least 20 ft of compacted
vegetation was necessary to produce a 1-ft-thick seam
of coal.
 This compacted coal is then converted into peat, a low-
grade fuel, then into brown, then into lignite, then into
sub bituminous coal, then into bituminous coal, and
finally into anthracitic coal.
 Aging process progresses, coal becomes harder,
hydrogen and oxygen fractions decrease, moisture
content decreases, and carbon fraction increases.

14. Coal composition and rank:
 Coal is an organic rock (as opposed to most
other rocks in the earth's crust, such as clays
and sandstone, which are inorganic).
 It contains mostly carbon (C), but it also has
hydrogen (H), oxygen (O), sulfur (S) and
nitrogen (N), as well as some inorganic
constituents (minerals) and water (H2O).

15. Coal composition and rank:
It is estimated that at least 20 ft of compacted
vegetation was necessary to produce a 1-ft-thick
seam of coal .

16. Coal composition and rank:
There are several different systems used for classifying coal, but the
American Society for Testing Materials (ASTM) has developed a method for
ranking coal into four major classifications:
Class I Coals: Anthracitic coals
 Class II Coals: Bituminous coals
 Class III Coals: Sub bituminous coals
Class IV Coals: Lignite coals

17. Liquid Fuels
 Almost all the commercial liquid fuels are derived
from natural petroleum. The liquid fuels consist of
hydrocarbons.
 The natural petroleum may be separated into
petrol or gasoline, paraffin oil or kerosene, fuel oils
and lubricating oil by boiling the crude oil at
different temperature and subsequent fractional
distillation.
 The following liquid fuels are important from the
subjects point of view.

18. Liquid Fuels
1. Petrol or gasoline: It is the lightest and most volatile liquid fuel,
mainly used for light petrol engines. It is distilled at a temperature
from 65˚-220˚C.
2. Kerosene or Paraffin oil: It is the heavier and less
volatile fuel than the petrol, and is used as heating and
lighting fuel. It is distilled from 220˚-345˚C
3. Heavy Fuel oil: The liquid fuels distilled after petrol and
kerosene are known as heavy fuel oil. These oils are
used in diesel engines and oil fired boilers. They are
distilled at a temperature from 345˚-470˚C.

19. Merits and Demerits of Liquid Fuel
over Solid Fuel
 Following are the merits and demerits Solid Fuel:
Merits:
1. Higher Calorific value.
2. Lower storage capacity required.
3. Better economy in handling.
4. Better control of consumption by using valves.
5. Practically no ashes.
6. Non-deterioration in storage.
7. Non-corrosion of boiler plants.
8. Higher efficiency.

20. Merits and Demerits of Liquid Fuel
over Solid Fuel
 Demerits:
1. Higher cost
2. Greater risk of fire.
3. Costly containers are required for storage
and transport.

21. Gaseous Fuel
 The natural gas is, usually found in or near the petroleum
fields, under the earth’s surface. It essentially consists of
marsh gas or methane(CH4) together with small
amounts of other gases such as ethane(C2H6), carbon
dioxide(CO2).
 The following gaseous fuels are important from
subject point of view.
1. Coal gas: It is obtained by carbonization of coal and
consists mainly of H2,CO and various hydrocarbons.
2. Producer Gas: It is obtained by the partial
combustion of coal, coke, anthracite coal or charcoal
in a mixed air-steam blast.

22. Gaseous Fuel
 Water gas: It is a mixture of H2 and CO and is
made by passing steam over incandescent
coke.
 Mond Gas: It is produced by passing air and a
large amount of steam over waste coal at about
650C.
 Blast Furnace Gas: It is a by-product in the
production of pig iron in the blast furnace.
 Coke oven gas: It is by-product from coke
oven and is obtained by the carbonization of
bituminous coal.

23. Merits and Demerits of Gaseous
Fuel:
 Merits:
1. The supply of fuel gas and hence the temperature
of furnace is easily and accurately controlled.
2. The high temperature is obtained at a moderate
cost by pre-heating gas and air with heat of waste
gases of combustion.
3. They are directly used in internal combustion
engine.
4. They do not produce ash or smoke.
5. They undergo complete combustion with minimum
air supply.

24. Merits and Demerits of Gaseous
Fuel
 Demerits:
1. They are readily inflammable.
2. They require large storage capacity.

25. Requirements of Good Fuel
1. A good fuel should have low ignition point.
2. It should have a high calorific value.
3. It should freely burn with a high efficiency,
one it is ignited.
4. It should not produce harmful gases.
5. It should produce least quality of smoke and
gases.
6. It should be economical, easy to store and
convenient for transportation.

26. Thermal power plants :-
 In thermal power plants the heat energy
produced by burning fossil fuels like coal,
petroleum or natural gas is used to heat
water and change it into steam which
rotates the turbines of generators to
produce electricity.

27. Thermal power plants :-

28. Thermal power plants :-

29. Thermal power plants :-

30. Hydro power plants :-
 In hydro power plants water from rivers are
stored by constructing dams. The water
from the dam flows down through pipes and
rotates the turbines of generators to
produce electricity.

31. Hydro power plants :-

32. Hydro power plants :-

33. Hydro power plants :-
 Advantages :-
i) Flowing water is a renewable source of energy.
ii) The electricity produced does not cause pollution.
iii) The water stored in dams can also be used to control floods
and for irrigation.
 Disadvantages :-
i) The initial cost is high.
ii) Large areas of land gets submerged and the decomposition
of vegetation produces methane gas which is a green house
gas.
iii) It causes displacement of people from large areas of land.

34. Non conventional sources of
Energy :-

35. Non conventional sources of
Energy :-
Biomass energy :-
 The waste materials and dead parts of living things are
called biomass. Eg :- wood, animal dung, vegetable
waste, agricultural waste, sewage etc. Biomass is
decomposed by anaerobic microorganisms to produce
biogas.
 Biogas is a mixture of gases containing methane, carbon
dioxide, hydrogen and hydrogen sulphide.

36. Biogas plant :-
The biogas plant has a large underground tank made of
bricks and cement. The lower part is the digester and
the upper part has a dome with a gas outlet. On one side
of the tank above the ground is a mixing tank and on
the other side is an overflow tank. Animal dung is
mixed with water in the mixing tank and the slurry is
sent into the digester. In the digester the slurry is
decomposed by anaerobic microorganisms and after a
few days biogas is produced. The gas is taken out
through the gas outlet and used for heating and lighting
purposes. The slurry left behind is rich in nitrogen and
phosphorus and is used as manure for crops.

37. FIXED DOME TYPE BIOGAS
PLANT

38. Wind energy :-
Wind energy is used in wind mills which converts the kinetic
energy of the wind into mechanical or electrical energy. The
kinetic energy of wind can be used to do mechanical work
like lifting water from wells or grinding grains in flour mills. It
can also be used to rotate the turbines of generators to
produce electricity.
A single wind mill produces only a small amount of electricity.
So a large number of wind mills in a large area are coupled
together to produce more electricity in wind energy farms.
Advantages :-
i) It is a renewable source of energy.
ii) It does not cause pollution.
iii) The recurring cost is less.
Disadvantages :-
i) Wind is not available at all times.
ii) It requires a large area of land.
iii) A minimum wind speed of 15 km/h is required

39. Solar energy :-
Solar energy is the energy obtained from the sun in the form of heat and light. The heat
energy is used in solar heating devices like solar cooker, solar water heater, solar
furnaces etc. The light energy is used in solar cells.
i) Solar cooker :- The box type solar cooker has an insulated box painted black
inside. It is covered by a glass plate which allows heat to enter inside but does not
allow heat to escape out. It has a mirror to reflect more sunlight into the box. The
food to be cooked is kept in containers inside the box It can produce a
temperature of 100° to 140°.

40. Solar energy :-
ii) Solar water heater :- A solar water heater has an insulated box painted black
inside with a system of copper tubes. It is covered with a glass plate which allows
heat to enter inside but does not allow heat to escape out. When water flows
through the copper tube it absorbs heat and becomes hot

41. Solar cells :-
Solar cell is a device which converts solar energy into electrical
energy. Solar cells are made from semi conductors like silicon,
germanium, gallium etc. A single solar cell produces a voltage of
about 0.5 to 1 V and produces about 0.7 W electricity. So several
solar cells are arranged in a solar panel to produce more electricity.

42. Solar cells :-
Advantages :-
i) It uses renewable source of energy.
ii) It produces electricity which does not cause pollution.
iii) It can be used in remote areas where there is no power supply.
Disadvantages :-
i) It uses a special grade of silicon which is expensive.
ii) Since silver is used for connecting the cells together it is more
expensive.
iii) The current produced is DC and to convert it to AC increases the cost.

43. Energy from the sea :-
Energy from the sea is obtained in three different forms. They are Tidal energy,
Sea wave energy and Ocean thermal energy.
i) Tidal energy :-
The periodic rise and fall of sea level due to gravitational attraction of the moon
causes tides. A dam is constructed at a narrow opening between the land and
sea. The movement of water during high tide and low tide can be used to
rotate the turbines of generators to produce electricity.

44. Energy from the sea :-
ii) Sea wave energy :-
When strong wind blows over the sea it produces huge waves. The kinetic energy
of the moving waves can be used to rotate the turbines of generators to
produce electricity.

45. Energy from the sea :-
iii) Ocean thermal energy :-
There is a temperature difference between the warm surface water and the cold
water at the bottom of the oceans. This difference is about 20°C. The warm
surface water is used to boil liquid ammonia and the vapour is used to rotate the
turbines of generators to produce electricity. The cold water from the bottom is
then pumped up to cool the vapour back to liquid

46. Geothermal energy :-
 The deeper regions of the earth’s crust is very hot. This heat melts
rocks and forms magma. The magma moves up and collects below at
some places called Hot spots. The underground water in contact with
hot spot gets heated into steam at high pressure. By drilling holes
into hot spots the steam coming out can be used to rotate turbines of
generators to produce electricity.

47. Nuclear energy :-
Nuclear energy is the energy is the energy released
during nuclear reactions. During nuclear reactions
some mass is converted into energy and so a very
large amount of energy is produced during nuclear
reactions. Nuclear reactions are of two types. They
are Nuclear fission and nuclear fusion

48. Nuclear energy :-
i) Nuclear fission :-
is a nuclear reaction in which the nucleus of a heavy atom like
uranium, plutonium, etc. splits into smaller nuclei with the
release of a large amount of energy. It is used to make atom
bombs and to produce electricity. In a nuclear power plant the
heat energy produced by a controlled nuclear fission chain
reaction is used to produce steam which rotates the turbines of
generators to produce electricity.

49. Nuclear energy :-
ii) Nuclear fusion :-
is a nuclear reaction in which small nuclei fuse
together to form a heavier nucleus with the release of
a very large amount of energy. The energy of sun is
produced by the fusion of hydrogen nuclei to form
helium nucleus. It is also used to make the hydrogen
bomb.

50. Nuclear energy :-
Advantages of nuclear energy :-
i) It produces a very large amount of energy per unit mass
than any other source of energy.
ii) If safety measures are taken, it is more environment
friendly than fossil fuels.
Disadvantages of nuclear energy :-
i) The cost of a nuclear reactor is very high.
ii) The availability of nuclear fuel is limited.
iii) Nuclear reactors produce harmful nuclear wastes which is
difficult to dispose.

51. Nuclear Power Plant