my geothermal

Tapping an inexhaustible Energy Source

Geothermal Energy

Azfar Rasool (12-EL-04)

CONTENTS

oWhat is Geothermal Energy?

oHistory

oResources

oDirect Applications

oGeothermal Electricity Generation

oAdvantages and Disadvantages

oConclusion

Origin of Geothermal Energy

CONTENTS


oHistory

oResources




oConclusion

History

• Hot springs have been used for bathing since centuries. The oldest known spa is a stone pool on China’s Lisan mountain built in the 3rd century BC.

• The world's oldest geothermal district heating system in France, has been operating since the 14th century.

• In 1911, the world's first commercial geothermal power plant was built at Larderello, Italy.

• In 1960, Pacific Gas and Electric Co. began operation of the first successful geothermal electric power plant in the USA.

• In 2014, 30715 MW of geothermal power was developed in 70 countries.

The oldest known pool fed by a hot spring, built by the Qin dynasty in the 3rd century BCE.

Today, Chevron Corporation is the world's largest private geothermal electricity producer.

then and now…

1904 2014

CONTENTS


oHistory

oResources




oConclusion

Resources

•The Earth's internal thermal energy flows to the surface by conduction at a rate of 44.2 TW.

•These power rates are more than double humanity’s current energy consumption from all primary sources, but most of this energy flow is not recoverable.

•The geothermal gradient of temperatures through the crust is 25–30 °C per kilometer of depth in most of the world.

•The conductive heat flux averages 0.1 MW/km2.

•Estimates of the potential for electricity generation from geothermal energy vary from 0.035 to 2TW depending on the scale of investments.

CONTENTS


oHistory

oResources




oConclusion

Direct Applications• It includes district heating, greenhouses, fisheries, mineral recovery,

industrial process heating, air conditioning, drying, aquaculture, melting snow, space heating, green house, etc. ???????HOW?????

• Low-temperature (149C or less) geothermal resources are typically used in direct-use applications.

• Iceland is the world leader in direct application of geothermal energy. 93% of its homes are heated with geothermal energy.

• Reykjavík, Iceland has the biggest district heating system on the globe.

Borehole Heat Exchanger

•Borehole heat exchanger is used for space heating.

•Water is sent down a well to be heated by the Earth’s warmth.

•Then a heat pump is used to take the heat from the underground water to the substance that heats the house.

• Then, after the water is cooled, it is injected back into the Earth.

14

…transfer this stored energy & use temperature

differences above & below the earth’s surface to

heat & cool buildings…

15

A geothermal heat pump

circulates water through a

sealed underground piping loop

where it is naturally warmed (or

cooled) by the earth

…using Heat Pump Technology

16

The Earth is the Source of Heat in Winter…

Outdoor air

design temperature:

-10°C20°C

70°C

A geothermal heat pump transfers underground heat into the building to provide heating

17

…and an Efficient Place to Reject or Store Heat in Summer…

Outdoor air

design temperature:

50°C30°C

70°C

A geothermal heat pump transfers heat from the building into the ground to provide cooling

DS-303

CONTENTS


oHistory

oResources




oConclusion

Types of Geothermal Power Stations

• Dry Steam Power Plants (Vapor Dominated)

• Flash Steam Power Plants (Liquid Dominated)

• Binary Cycle Power Plants

CONTENTS


oHistory

oResources




oConclusion

Conclusion

Advantages

• Non conventional energy source

• It is replenished by radioactive decay of minerals

• Unending source

• Continuous supply

• Cheap operation

Disadvantages

• Fluids drawn from the deep earth carry a mixture of gases, notably carbon dioxide , hydrogen sulfide and ammonia which contribute to global warming, acid rain

• Construction is too costly

• Noise pollution

• Land survey can be unreliable.

Thank You!

my geothermal

Engineering