Thermodynamics of Geothermal energy

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

I always wanted to try a trench coat and this one made me try more. It's fits me like a charm. I wear to while going for work and it serves it's purpose.

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

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

Some visible sources of geothermal energy Some visible sources of geothermal energy

are:are:

• DIRECT USE:• Geothermal Heating • Heat pumps

• INDIRECT USE:• Electricity production

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.

•

• 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)

• 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

Dry Steam Power PlantsDry Steam Power Plants• “Dry” steam extracted from natural reservoir

o 180-225 ºC ( 356-437 ºF)o 4-8 MPa (580-1160 psi)o 200+ 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

o A 55 MW plant requires 100 kg/s of steam

Flash Steam Power Flash Steam Power PlantsPlants

• 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

Binary Cycle Power Binary Cycle Power PlantsPlants

• Low temps – 100o and 150oC• Use heat to vaporize organic liquid

o E.g., iso-butane, iso-pentane• Use vapor to drive turbine

o Causes vapor to condenseo Recycle continuously

• Typically 7 to 12 % efficient• 0.1 – 40 MW units common

• Geothermal heat is used directly rather than for power generation

• Extract heat from low temperature geothermal resources◼< 150 oC or 300 oC.

• Applications sited near source (<10 km

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

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.

• PRESENTED BY:• Abrar Khan• Abhishek Menon• Bharath • Anuj taraiya• Chirag

THANK YOU

22