Geothermal Flashcards
Geothermal energy
Thermal energy within the earth’s interior
Why it is considered re?
Because heat is continuously transferred from the earth to the water recycled by rainfall
Interior of the earth is made of:
1-Inner core 6500 km deep (iron center)
2-Outer core made from hot magma with high temps due to decay of radioactive particles
3- mantle, thickness 3000 km made of magma and rocks
4- crust, 25 to 55 km on the continentsand 5-8 km under the oceansmade of tectonic plates - volcanoes occur near the edge of these plates dove to magma getting close to it
How we make use of geothermal energy
At some depth, rocks and water absorb heat from magma, these are geothermal resources, by digging wells and pumping hot water to the surface, we use geo.
History of geothermal
1- hot springs used for bathing millions years ago..
2- geothermal generated electricity was in that produced Italy 1904.
3- first direct exchange ground - source heat pump in 1940
Geothermal energy definition
Thermal energy generated and stored in the earth
Thermal energy
Energy that determines the temp of matter, geothermal is heat transferred by conduction
Geothermal energy of the earth’s crust originates from?
Original formation of the planet (20%),radioactive decay of minerals (80%)
Geothermal gradient
Difference in temp between the core of the planet and its surface, drives continuous conduction of thermal energy in the form of heat from the core to the surface
How geothermal occur?
1 - at the core of earth, thermal energy is created by radioactive decay, temps reach 5000C, heat conducts from the core to surrounding cooler rock.
2-high temp and pressure cause some rocks to melt creating magma.
3- magma convection upward because its lighter than solid rocks.
4-magma heat the rocks and water in the crust up to 370C.
5-ground water near dormant volcanois heated by reservoirs of molten rock on 3 km depth.
6- wells are drilled to recover the water, when capturedsteam and hot water are separated - steam is cleaned and sent to the power plant, wateris returned to the reservoir by injection wells.
Geothermal energy world status
- geothermal electricity production: US - Philippines - Indonesia
- geothermal direct use: china- US - Sweden
Types of technologies and classifications of geo resources
1- high energy: temp between 150-350 C , geothermal electricity production.
2- medium energy: temp between 80-150 C, geothermal direct use, heat.
3- low energy: temp less than 80 C, geothermal direct use heat pumps, use shallow ground to heat or cool buildings.
Environmental impacts
1- land: vegetation loss, soil erosion, land slides.
2- air: slight air heating, local fogging.
3- ground: reservoir cooling, tremors.
4- water: watershed impact, damming streams, hydrothermal eruptions, lower water table, subsidence.
5- noise
Geothermal potential in Jordan
Jordan is part of the ring of fire, have medium energy (110-114C) and low energy (30-64C) , location of all thermal springs is dead sea rift
Geothermal gradient ,ap of jordan shows two distinct regions of high geo gradients up to 50 C/ km
Wells near queen alia airport, shoneh, maeen thermal spring
Geothermal electricity production
Geothermal power plants use steam produces from reservoirs of hot water found below the earth surface to produce electricity
Types of geothermal power plants
Dry steam- flash steam (single, double ), - binary cycle
Dry steam power plants
Extracted from natural reservoirs / 180-225 C/4-8 Mpa/ 55.5 m/s or 200 km/hr
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 stea
Single flash steam power plants
Steam with water extracted from ground.
Pressure of mixture drops at surface and more water flashes to steam.
Steam seperated from water then drives a turbine.
Turbine drives an electric generator.
Generate between 5 and 100 MW
Use 6 to 9 tones of steam per hour to produce mw.
Have brine water to make the evaporation quicker.
When pressur drops, water is pumped, and turbine moves, thats why its called flash
Double flash power plants
Unflashed liquid flow into low pressure tank, flashes to steam.
Steam drives a second stage turbine and also use exaust from first turbine.
Increase output 20-25% for. 5% cost increase
Binary cycle power plants
Low temp 100-150 C
Use heat to vaporize organic liquid.
Use vapor to drive turbine, vapor condense, recycle continuously.
7-12% efficient.
0.1-40 mw
Working fluid in binary power plant
Organic fluid: iso-butane / iso-pentane / ammonia
Combined cycle plants
Combination of conventional steam turbine and binary cycle.
Steam drives primary turbine, remining heat used to create organic vapor, organic vapor drives a second turbine.
Size from 10 to 100 mw
Greater efficiency, higher urilization, extract more power and heat from geo resource
Hot dry rock technology
Wells drilled 3-5 km into crust, hot crystalline rock formations.
Water pumped into formations.
Water flows through natural cracks. (Formations) picking up heat.
Hot water/ steam returns to surface.
Steam used to generate power
Geothermal direct use for sources between. 80-150 C
Space heating
Air conditioning
Aquaculture
Drying
Greenhouses
Industrial processes.
Hot water.
Resorts and pools.
Melting snow
