UNIT-3
Contents as per syllabus:
1. Geothermal Energy
1.1. Introduction
1.2. Where is it found?
1.3. Resources of geothermal energy
1.4. Thermodynamics of geothermal energy conversion-electrical
conversion & non-electrical conversion
1.5. Geothermal Power Plants
1.6. Environmental considerations
1.7. Performance
2. Magneto-hydrodynamics (MHD)
2.1. Introduction
2.2. Principle of working of MHD Power plant
2.3. MHD System
2.4. Types of MHD Systems
2.5. Advantages and Disadvantage of MHD Systems
3. Fuel Cells
3.1. Introduction
3.2. Principle of working of fuel cells
3.3. Classification of Fuel Cells
3.4. Working Principle of different types of Fuel Cells
3.5. Advantages over conventional resources of energy
3.6. Limitations
3.7. Applications
,4. Short Answer Questions
5. University asked Questions
6. MCQs
,1. Geothermal Energy
1.1. Introduction
Geothermal energy—geo (earth) + thermal (heat)—is heat energy from the earth. Geothermal energy
comes from the heat within the earth.
People around the world use geothermal energy to produce electricity, to heat buildings and
greenhouses, and for other purposes.
The earth's core lies almost 4,000 miles beneath the earth's surface.
The double-layered core is made up of very hot molten iron surrounding a solid iron center.
Estimates of the temperature of the core range from 5,000 to 11,000 degrees Fahrenheit (F).
Heat is continuously produced within the earth by the slow decay of radioactive particles that is
natural in all rocks.
Surrounding the earth's core is the mantle, thought to be partly rock and partly magma. The mantle is
about 1,800 miles thick.
The outermost layer of the earth, the insulating crust, is not one continuous sheet of rock, like the shell
of an egg, but is broken into pieces called plates. These slabs of continents and ocean floor drift apart
and push against each other at the rate of about one inch per year in a process called continental drift.
Magma (molten rock) may come quite close to the surface where the crust has been thinned, faulted,
or fractured by plate tectonics. When this near-surface heat is transferred to water, a usable form of
geothermal energy is created. Geothermal energy is called a renewable energy source because the
water is replenished by rainfall, and the heat is continuously produced by the earth.
, Fig.1. Earth’s Core
1.2. Where is it found?
Some visible features of geothermal energy are volcanoes, hot springs, geysers, and fumaroles.
Geologists use many methods to find geothermal resources.
They may study aerial photographs and geological maps. They may analyze the chemistry of local
water sources and the concentration of metals in the soil.
They may measure variations in gravity and magnetic fields. Yet the only way they can be sure
there is a geothermal resource is by drilling wells to measure underground temperatures.
The earth is a hotbed of geothermal energy. The most active geothermal resources are usually found
along major plate boundaries where earthquakes and volcanoes are concentrated.
Most of the geothermal activity in the world occurs in an area known as the "Ring of Fire." The
Ring of Fire rims the Pacific Ocean and is bounded by Japan, the Philippines, the Aleutian Islands,
North America, Central America.
Contents as per syllabus:
1. Geothermal Energy
1.1. Introduction
1.2. Where is it found?
1.3. Resources of geothermal energy
1.4. Thermodynamics of geothermal energy conversion-electrical
conversion & non-electrical conversion
1.5. Geothermal Power Plants
1.6. Environmental considerations
1.7. Performance
2. Magneto-hydrodynamics (MHD)
2.1. Introduction
2.2. Principle of working of MHD Power plant
2.3. MHD System
2.4. Types of MHD Systems
2.5. Advantages and Disadvantage of MHD Systems
3. Fuel Cells
3.1. Introduction
3.2. Principle of working of fuel cells
3.3. Classification of Fuel Cells
3.4. Working Principle of different types of Fuel Cells
3.5. Advantages over conventional resources of energy
3.6. Limitations
3.7. Applications
,4. Short Answer Questions
5. University asked Questions
6. MCQs
,1. Geothermal Energy
1.1. Introduction
Geothermal energy—geo (earth) + thermal (heat)—is heat energy from the earth. Geothermal energy
comes from the heat within the earth.
People around the world use geothermal energy to produce electricity, to heat buildings and
greenhouses, and for other purposes.
The earth's core lies almost 4,000 miles beneath the earth's surface.
The double-layered core is made up of very hot molten iron surrounding a solid iron center.
Estimates of the temperature of the core range from 5,000 to 11,000 degrees Fahrenheit (F).
Heat is continuously produced within the earth by the slow decay of radioactive particles that is
natural in all rocks.
Surrounding the earth's core is the mantle, thought to be partly rock and partly magma. The mantle is
about 1,800 miles thick.
The outermost layer of the earth, the insulating crust, is not one continuous sheet of rock, like the shell
of an egg, but is broken into pieces called plates. These slabs of continents and ocean floor drift apart
and push against each other at the rate of about one inch per year in a process called continental drift.
Magma (molten rock) may come quite close to the surface where the crust has been thinned, faulted,
or fractured by plate tectonics. When this near-surface heat is transferred to water, a usable form of
geothermal energy is created. Geothermal energy is called a renewable energy source because the
water is replenished by rainfall, and the heat is continuously produced by the earth.
, Fig.1. Earth’s Core
1.2. Where is it found?
Some visible features of geothermal energy are volcanoes, hot springs, geysers, and fumaroles.
Geologists use many methods to find geothermal resources.
They may study aerial photographs and geological maps. They may analyze the chemistry of local
water sources and the concentration of metals in the soil.
They may measure variations in gravity and magnetic fields. Yet the only way they can be sure
there is a geothermal resource is by drilling wells to measure underground temperatures.
The earth is a hotbed of geothermal energy. The most active geothermal resources are usually found
along major plate boundaries where earthquakes and volcanoes are concentrated.
Most of the geothermal activity in the world occurs in an area known as the "Ring of Fire." The
Ring of Fire rims the Pacific Ocean and is bounded by Japan, the Philippines, the Aleutian Islands,
North America, Central America.
