Geothermal Energy is heat (thermal) derived from the earth (geo). •It is the thermal energy from the earth's core, which is stored in the rock in the earth's crust.

1. Geothermal Energy Systems
Guided by:
Ar.Firoz Anwar
ContemporaryTechnology
Presented by:
Md Waseem Reza
Mohd. Khalid Raza
M.Arch, I Sem.
(Building Services)

2. Direct
Industrial &
Domestic heating
HVAC
Mineral recovery
Greenhouses
Indirect
Electricity
generation
Geothermal Energy
• Geothermal Energy is heat (thermal)
derived from the earth (geo).
•It is the thermal energy from the
earth's core, which is stored in the
rock in the earth's crust.
DefinitionApplicationsAdvantages
• Renewable
•Environment friendly
•Sustainable
•Cost effective
Worldwide use of Geothermal Energy for Direct use
Source: www.geofund.info/uploads/images/geofund%20images/geothermal_energy_utilization.JPG
Limitations:
• Not every area has accessible
geothermal sources.
•Green house gases emission.
•Localized Depletion
Hot water spring Geothermal Power Plant
Presented by: Md Waseem Reza & Mohd khalid Raza Slide Number: 1.

3. Geothermal Energy Systems
• Systems that utilizes the thermal energy stored in
earth.
Principle
• Earth behaves as a huge collector-
cum-storage medium.
• Beyond 4 m depth earth
temperature remains constant ( equal
to mean air temperature at surface),
since it absorbs only 50% of all solar
energy
Waysoftapping
Geothermal
energy
indirect
coupling
Earth air
tunnel
Geothermal
exchange
systems
direct coupling
earth envelope
Geothermal Gradient
Source: http://www3.uakron.edu/geology/Foos/Energy/1geot9.gif&imgrefur
Slide Number: 2.
Earth’s Temperatures

4. • Architectural practice of using earth
against building walls.
•Passive solar & sustainable
architecture.
Definition
Direct coupling- earth envelopes
• Earth berming
•In-hill construction
•Underground/fully recessed
construction
Typology
• Taking advantage of the earth as a
thermal mass.
•Offering extra protection from the
natural elements
•Energy savings
•Efficient use of land in urban
settings
•Shelters have low maintenance
requirements
Advantages
• Water seepage
•Internal condensation
•Bad acoustics
•Poor indoor air quality.
•Requires heavier construction than
conventional building techniques
Limitations
Earth sheltering
In-hill construction
Earth berming
underground/fully recessed
Cross-section
Slide Number: 3.

5. • An active technique that applies geothermal energy in required purposes using ground source exchange.
Indirect coupling – Geothermal exchange systems
Ground Loop system Heat Transfer fluid Heat Pump Air distribution
system
ComponentsWorking
Circulation of fluid through pipes
buried in ground
Exchange of heat either-way ( from
fluid to earth or vice-versa)
Electrically driven concentrates this
energy & release it at desired
temperature
Distribution through various
distribution systems
Slide Number: 4.

6. The earth connection is where heat transfer between the GSHP system and the soil occurs.
Ground loop system
Types
Ground loop
system
Closed loop
Horizontal
Vertical
Slinky
Pond
Open loop
Well to Well
Slide Number: 5.

7. • Central heating and/or cooling system that pumps heat to or from the ground
Geothermal heat pump
Classification
Geothermal
heat pumps
Function
based
Heating
Cooling
Domestic water
heating
Ventilation
Drying
Heat recovery
Heat source
based
Ground
Ground
water
Surface
water
Air
Exhaust
air
Working
fluid based
Unit
construction
based
Brine/water
Water/water
Direct
expansion/w
ater
Air/water
Air/air
Compact, split
Installation
location (indoor,
outdoor)
Compressor heat
pump
Absorption heat
pump
Number of
compression
stages
Desuper heater
Absorption heat pump
Air to air
Water to water
Slide Number: 6.

8. Components – Geothermal heat pump
Working
compressor
Loop-to-refrigerant heat
exchanger
controls
•It consists of-
Slide Number: 7.

9. Components – Heat Transfer Fluid & Distribution system
•It is the refrigerant that circulates throughout the loop
• The decision to use water or antifreeze(propylene glycol, denatured alcohol or methanol) in the loop system depends
on a number of factors, such as the type of loop system installed and local conditions.
•Most residential geothermal systems use conventional ductwork to distribute hot or cold air and to provide humidity
control.
•A few systems use water-to-water heat pumps with one or more fan-coil units, baseboard radiators, or under-floor
circulating pipes.
• Properly sized, constructed, and sealed ducts are essential to maintain system efficiency.
• Ducts must be well insulated and, whenever possible, located inside of the building's thermal envelope).
Workingsystems
Hydronic heating systems.
•Also known as forced air
distribution systems
•Hot water is circulated through
radiators or a system of in-floor
pipes to provide heat.
Forced air system
•A fan in the heat pump blows over
a fan coil and the heated or cooled
air is circulated throughout the
house or building.
•Most common as they tend to be
the most economical and they also
provide both heating and cooling
functions.
Distributionsystem
Slide Number: 8.

10. Summary- Geothermal Exchange Systems
Vertical ground loop system
Vertical pipe connected to heat
pump
Heat pump
Slide Number: 9.

11. Summary- Geothermal Exchange Systems

12. Comparative with conventional systems
Same system can
be used for more
cooling area
Low Tonnage
requirement Reduced capacity Increased
economy
Lesser run time of
system
Reduced power
consumption upto
20-30%
Lower operational
costs
Increased
economy
Slide Number: 10.

13. Comparison with conventional systems
Advantages
Environmental benefits
Operating cost
Self sufficient
Non-flamability
Sustanibility
Retrofit
Multiple functions
Durable and highly
reliable
Low Noise
Unobstrutive
Assured Availability
Disadvantages
High installation costs
Cumbersome
Installation
Heavy machinery
required
Space requirement for
loops
Greater pay back
period
Frost time difficulties
in some countries.
Not every area has
accessible geothermal
sources.
ArchitecturalAdvantages
Space saving benefits
Elevational
considerations
Reduction in overall
load requirement of
building
Reduced ducting
requirements
Overall low initial and
running cost
Slide Number: 11.

14. Practical applications in India
TheIndianContext
•In India ground sink temperature remains between 20-25˚C.
•Enough load temperature is not available.
•Practical use merely limited to precooling fresh air to be used by conventional air-conditioning system.
•The system may be effective in peak summers and winters but fails in monsoon.
•Refrigerant- based dehumidifiers/ chillers need to be used in addition.
•Not extensively used in India.
Slide Number: 12.

15. • A passive technique consisting of a tunnel for passage
of calculated amount of air for the purpose of HVAC of a
space using natural heat of the earth, 4 m below the
earth surface.
•Also known as ground- coupled heat exchanger or earth-
tube heat exchanger.
•Used for either partial or full cooling and/or heating of
facility ventilation air
Indirect coupling – Earth Air Tunnel
Earth
Air
Tunnel
Open
loop
System
Closed
Loop
System
Combination
system
Types
Space to be
conditioned Surface
OverviewPrinciple
•Uses constant air temperature
below 4 m of earth’ surface.
•Air blown through long cement of
metal tubes buried in earth.
•Heat Dissipated through surface
contact.
•Conditioned air supplied to space
Earth Air Tunnel
4 m
Open System
Space to be
conditioned
Surface
U bend Earth Air Tunnel
Closed System
Space to be
conditioned
Surface
Earth Air Tunnel
Combination System
Slide Number: 13.

16. Indirect coupling – Earth Air Tunnel
Inlet Inline fan
(optional) Filter
Concrete/plastic
coated metal/ plastic
coated with
antimicrobial layer
tubes acting as tunnel
Outlet Blower
Air
Handling
Unit
(optional)
Air
distribution
system
Air
exhaust
system
ComponentsWorking
Fresh Air sucked in through inlet.
Inlet air filtered
(mechanically/ natural filters)
Air passed through the length of
tunnel. Heat gained/ lost through
surface contact
Conditioned air supplied to AHU
through blowers
AHU contains evaporative
coolers(summers)/dehumidifiers
(monsoons)/ chillers/cooling pads.
Air Distribution, circulation and re-
circulation of return air
Air Exhaust through solar
chimneys/ exhausts
Schematics Earth Air Tunnel
Slide Number: 14.

17. Indirect coupling – Earth Air Tunnel
Efficiency
Efficiency
Surface Area available
for contact
Length of tube
Diameter of
tube
Soil Type Clayey Soil is most effective.
Sandy soil is least
Season
Works best in dry summer
and winters
Soil Conditions
Depth of water
table
Depth of tunnel
Surface
conditions Shady, sunlit, wet, dry,
combination
Efficiency of EAT
Slide Number: 15.

18. Indirect coupling – Earth Air Tunnel
Advantages
Cost saving
Reduces air pollution
Energy saver
Reduces green house
gases
100% fresh air without
recirculation
Retrofit
Durable
Low Noise
Unobtrusive
Assured Availability
High installation costs
Cumbersome Installation
Subject to climate
Need add-ons to achieve
effective conditioning
Large space required
Frost time difficulties in
some countries.
Not every area has
accessible geothermal
sources.
Long payback period
Limitations
Slide Number: 16.

19. Indirect coupling – Earth Air Tunnel
Entire Scheme and passive
factors effecting it
Slide Number: 17.

20. Practical application in India
NIITUniversity,Neemrana,Rajasthan
•EAT used for P.G. hostels and Academic
block.
•Tunnels cool outside air from 44/360C to
280C.
•18 tunnels to handle 2 Lac CFM
•Each Tunnel 90m long to handle 12000
CFM -18000 CFM
•8 air change/Hrs. in Peak Summer and 3
air change/Hrs. during Monsoon & Winter
•Displacement Ventilation for Proper Air
Circulation
•Special AHUs for recooling &
Dehumidifying air for each Tunnel.
Slide Number: 18.
TUNNEL LAYOUT ON SITE
Source: http://nma-design.com/green-school/index_htm_files/8%20Vinod%20Gupta%20-%20NIIT%20Campus.pdf

21. Indirect coupling – Earth Air Tunnel
RETREAT,GualPahari
•EAT used for south block living
quarters.
•Tunnels cool outside air from to 30-
280C.
•4 tunnels to handle 6,000CFM
•Each Tunnel 70 m with 70 cm dia.
•4 fans 2 HPeach force air in.
•Solar chimney force air out.
•Supplemented by 10 TR
dehumidifier and chillers.
Slide Number: 19.

22. Electricity Generation
There are 3 types of power plants:-
 Dry steam power plant
Flash steam power plant
Binary cycle power plant
Slide Number: 20.
• Earth’s core heat
• Water → steam → drive electrical generators
• Turbines
• Area specific
• Geothermal energy is localized
Geothermal energy is simply power derived from the Earth's internal
heat. This thermal energy is contained in the rock and fluids beneath
Earth's crust. It can be found from shallow ground to several miles
below the surface, and even farther down to the extremely hot
molten rock called magma.
These underground reservoirs of steam and hot water can be tapped
to generate electricity.
Geothermal power plant
Most power plants need steam to generate electricity. The steam
rotates a turbine that activates a generator, which produces
electricity. Many power plants still use fossil fuels to boil water for
steam. Geothermal power plants, however, use steam produced from
reservoirs of hot water found a couple of miles or more below the
Earth's surface. There are three types of geothermal power
plants: dry steam, flash steam, and binary cycle.
Source http://geo-energy.org/Basics.aspx

23. Steam is produced directlyfrom the geothermal reservoir to run the turbines
that power the generator, and no separation is necessary because wells only
produce steam.
This is the oldest type ofgeothermal power plant. It was first used at Lardarello
in Italyin 1904.
Dry Steam Power Plant
Geothermally heated water under pressure is separated in a surface
vessel (called a steam separator) into steam and hot water (called “brine).
The steam is delivered to the turbine, and the turbine powers a
generator. The liquid is injected back into the reservoir.
Flash Power Plant
Slide Number: 21.
Source http://geo-energy.org/Basics.aspx

24. The geothermal water heats another liquid, such as isobutane or other organic
fluids such as pentafluoropropane, which boils at a lower temperature than water.
The two liquids are kept completely separate through the use of a heat
exchanger, which transfers the heat energy from the geothermal water to the
working fluid.
The secondary fluid expands into gaseous vapor. The force of the
expanding vapor, like steam, turns the turbines that power the generators. All
of the produced geothermal water is injected back into the reservoir.
Binary Power Plant
Slide Number: 22.
Source http://geo-energy.org/Basics.aspx

25. Environmental Impacts
• Land
– Vegetation loss
– Soil erosion
– Landslides
• Air
– Slight air heating
– Local fogging
• Ground
– Reservoir cooling
Seismicity (tremors)
Advantages of Geothermal Energy
Geothermal Energy is a renewable source of energy.
By far, it is non-polluting and environment friendly.
There is no wastage or generation of by-products.
Maintenance cost of geothermal power plants is very less.
Geothermal power plants don't occupy too much space and thus help in
protecting natural environment.
Unlike solar energy, it is not dependent on the weather conditions.
Slide Number: 23.

26. Disadvantages of Geothermal Energy
Only few sites have the potential of Geothermal Energy.
Most of the sites, where geothermal energy is produced, are far from markets or cities, where it needs
to be consumed.
There is always a danger of eruption of volcano.
Installation cost of steam power plant is very high.
There is no guarantee that the amount of energy which is produced will justify the capital expenditure
and operations costs.
It may release some harmful, poisonous gases that can escape through the holes drilled during
construction.
Slide Number: 24.

27. Summary- Geothermal Electricity Generation

28. Bibliography
•Energy efficient buildings in India, by Mili Majumdar, TERI, India, Ministry of
Non-conventional energy sources, pg. 115
•Performance evaluation and energy conservation potential of earth air tunnel
system coupled with non air- conditioned building : Building & environment by,
Kumar, R. Ramesh, S. Kaushik
•Geothermal heat pumps: a guide for planning & installing by Karl Ochsner,
Earthsean Publishers , U.K.
BooksReferred:
• www. Wikipedia.com
•www.indiaarchitectureinfo.com
Websites: