Thermodynamics of Geothermal energy

INTRODUCTION TO GEOTHERMAL ENERGY
SOURCES OF GEOTHERMAL ENERGY
ROLE OF THERMODYNAMICS IN GEOTHERMAL POWER-PLANT
TYPES OF GEOTHERMAL POWER-PLANTS AND THEIR WORKING
DIRECT USE OF GEOTHERMAL ENERGY
ADVANTAGES AND DISADVANTAGES OF GEOTHERMAL ENERGY

2. Geothermal power is from the Greek
words ‘Geo’ meaning earth and
‘Thermal’ meaning heat
Geothermal energy is generated by
heat stored beneath the Earth’s
surface or the collection of absorbed
heat in the atmosphere heat in the
atmosphere and oceans
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3. A renewable energy source because the water is replenished
by rainfall and the heat is continuously produced inside the
earth.
Geothermal energy is generated in the earth's core, about
4,000 miles below the surface.
Temperatures hotter than the sun's surface are continuously
produced inside the earth by the slow decay of radioactive
particles, a process that happens in all rocks

4. •An area called RING OF FIRE has most of
geothermal activities, this borders the pacific
ocean

5. Some visible sources of geothermal energy are:Some visible sources of geothermal energy are:

6. •DIRECT USE:
•Geothermal Heating
•Heat pumps
•INDIRECT USE:
•Electricity production

7. Role of Thermodynamics
•The production of electricity from a geothermal
source is about producing work from heat
•Electricity production from heat will never be
successful unless appropriate respect is paid to
the second law of thermodynamics.
•

8. •Low Temperature
Reservoirs:
•The temperature of
these reservoirs is
between 100 and 30 °C
◼ Available almost
anywhere on earth
◼Predominantly used
for heating things
(various reasons)

9. •High Temperature Reservoirs:
Availability:
◼Where Earth’s crust is very thin
◼Suitable for Commercial
Production of Electricity
▫Power Plants Need High
Capacity Geothermal
Reservoir – Water / Steam
>220°F (105°C)
◼Greatest Potential for Energy
Output

11. Dry Steam Power PlantsDry Steam Power Plants
•“Dry” steam extracted from natural reservoir
o180-225 ºC ( 356-437 ºF)
o4-8 MPa (580-1160 psi)
o200+ km/hr (100+ mph)
•Steam is used to drive a turbo-generator
•Steam is condensed and pumped back into the
ground
•Can achieve 1 kWh per 6.5 kg of steam
oA 55 MW plant requires 100 kg/s of steam

13. Flash Steam Power PlantsFlash Steam Power Plants
•Steam with water extracted from ground
•Pressure of mixture drops at surface and more water
“flashes” to steam
•Steam separated from water
•Steam drives a turbine
•Turbine drives an electric generator
•Generate between 5 and 100 MW
•Use 6 to 9 tonnes of steam per hour

15. Binary Cycle Power PlantsBinary Cycle Power Plants
•Low temps – 100
o
and 150
o
C
•Use heat to vaporize organic liquid
oE.g., iso-butane, iso-pentane
•Use vapor to drive turbine
oCauses vapor to condense
oRecycle continuously
•Typically 7 to 12 % efficient
•0.1 – 40 MW units common

17. •Geothermal heat is used directly
rather than for power generation
•Extract heat from low temperature
geothermal resources
◼< 150
o
C or 300
o
C.
•Applications sited near source (<10
km

19. 1) It is a renewable source of energy.
2) By far, it is non-polluting and environment friendly.
3) There is no wastage or generation of by-products.
4) Geothermal energy can be used directly. In ancient
times, people used this source of energy for heating
homes, cooking, etc.
5) Maintenance cost of geothermal power plants is very
less.
6) Geothermal power plants don't occupy too much
space and thus help in protecting natural environment.
7) Unlike solar energy, it is not dependent on the weather
conditions.
ADVANTAGES OF GEOTHERMAL ENERGY

20. DISADVANTAGES:
1) Only few sites have the potential of Geothermal Energy.
2) Most of the sites, where geothermal energy is produced,
are far from markets or cities, where it needs to be
consumed.
3) There is always a danger of eruption of volcano.
5) Installation cost of steam power plant is very high.
6) There is no guarantee that the amount of energy which is
produced will justify the capital expenditure and operations
costs.
7) It may release some harmful, poisonous gases that can
escape through the holes drilled during construction.

22. •PRESENTED BY:
•Abrar Khan
•Abhishek Menon
•Bharath
•Anuj taraiya
•Chirag
THANK YOU
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