nc denr geothermal overview presentation · geothermal overview geothermal benefits have helped...

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Presented by John Cole – East Coast Account Rep. for RENEWABLE ENERGYGEOTHERMAL OVERVIEW

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GEOTHERMAL OVERVIEWWHAT IS GEOTHERMAL AND HOW DOES IT WORK?

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GEOTHERMAL OVERVIEW

Definition- Geo (Earth) thermal (heat)- Geothermal = heat exchange with the Earth- Geoexchange is gaining popularity

- This term describes the entire system from ground loops to circulation pumps to the heat pump

Where does the energy come from?- The Earth's core

- Radioactive decay- The sun

- Insolation impacts the outer crust

WHAT IS GEOTHERMAL ENERGY?

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- Heat is continually supplied to the ground in the form of solar energy

- Approximately 46% of the sun’s energy is absorbed by the Earth (U.S. Dept. of Energy)

- At a depth of approximately 15 feet the ground temperature remains fairly constant, with a mean annual Earth temperature of 42°-77°F (depending on location)

THE TEMPERATURE OF THE EARTH

GEOTHERMAL OVERVIEW

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MEAN ANNUAL EARTH TEMPERATURES

EARTH’S UNIQUE THERMAL INSULATION CAPABILITY

GEOTHERMAL OVERVIEW

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Line 1 = FebruaryLine 2 = MayLine 3 = NovemberLine 4 = August

Ground Temperature– The greater the depth, the more

stable the ground temperature is– “Thermal lag”, the seasonal effect,

is more dramatic at shallow depths

– Example from a specific U.S. region

STABLE EARTH TEMPERATURE

GEOTHERMAL OVERVIEW

Temperature (°F)32 41 50 59 68

Dep

th (

ft)66

50

3

3

16

0

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HOW DOES IT WORK

0°F

A Geothermal System absorbs heat from the ground in winter & transfers the heat into the building…

40-60°F

Insulating layer of earth

70°F

GEOTHERMAL OVERVIEW

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HOW DOES IT WORK

100°F

…and cools the building in summer by rejecting heat to the ground

40-60°F

Insulating layer of earth

70°F

GEOTHERMAL OVERVIEW

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Principles– A geothermal system gets the majority of its energy from the earth’s latent heat– A geothermal system “pumps” heat from one location to another

25%(1 unit of purchased

electricity)

75%(3 units of free energy from the Earth)

100%(4 units of heat to the building)

HOW DOES IT WORK?

GEOTHERMAL OVERVIEW

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- Ground loop (Earth): A sealed and pressurized closed loop pipe system circulates water/antifreeze solution below the Earth’s surface

- Refrigerant loop (Heat pump):A sealed and pressurized loop transfers the thermal energy in the heat pump through the compressor

- Air loop (Air distribution):Distributes conditioned air to the building

- Desuperheater loop (optional):For Domestic Hot Water

HOW DOES IT WORK?

GEOTHERMAL OVERVIEW

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Ground Source Heat Pumps are:

- “Electrically powered systems that tap the stored energy of the greatest solar collector in existence: the Earth. These systems use the Earth's relatively constant temperature to provide heating, cooling, and hot water for homes and commercial buildings.“ *

- Efficient, cost effective and environmentally-friendly heating/cooling systems

*International Ground Source Heat Pump Association (IGSHPA)

GEOTHERMAL OVERVIEWSUMMARY

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GEOTHERMAL OVERVIEWWHAT BENEFITS DO GEOTHERMAL SYSTEMS OFFER YOU?

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Heating 30% - 70% energy savings

Cooling 20% - 50% energy savings

PRIMARY BENEFITS: ENERGY SAVINGS

GEOTHERMAL OVERVIEW

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COPEnergy Source

4.0

0.93

0.85

0.88

1.00

Geothermal

Natural Gas

Fuel Oil

Propane

Electrical Resistance

COP = Total energy produced by system / energy purc hasedor

COP = “What you got / what you bought”


COP = COEFFICIENT OF PERFORMANCE

GEOTHERMAL OVERVIEW

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Net Cost (USD) / 1,000,000 BTU

Cost / Energy Unit (Efficiency)

Energy Source

$0.08/kWh @ 4.0 COP (400%)

$1.30/Therm (93%)

$2.50/Gal (85%)

$2.75/Gal (88%)

$0.08/kWh (100%)

$5.69Geothermal

$14.00Natural Gas

$21.00Fuel Oil

$34.00Propane

$22.75Electrical Resistance


SAMPLE COSTS - VIRGINIA, LATE 2008

GEOTHERMAL OVERVIEW

Conversions:1 kW = 3413 BTU; 1 Gal Propane = 92,000 BTU; 1 Gal No. 2 = 140,000 BTU; 1 Therm = 100,000 BTU

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GEOTHERMAL OVERVIEW

Geothermal benefits have helped government officials to understand the positive impact thatthese systems have on energy independence, the environment and national security.

Federal tax incentives as part of the 2009American Recovery and Reinvestment Act

- An uncapped 30% residential tax credit isavailable for each residential GHPinstallation

- A 10% federal grant is available for eachcommercial installation

- Incentives last through 2016

BENEFITS LEAD TO GOVERNMENT INCENTIVES

All 50 states have some kind of GHP IncentiveVisit the Database of State Incentives for Renewables and Efficiency (www.dsireusa.org) website for a list

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GEOTHERMAL OVERVIEW

Geothermal benefits have helped government officials to understand the positive impact thatthese systems have on energy independence, the environment and national security.

29 states have financial incentives- Sales tax and property tax exemptions,

income tax credits and grants

31 states have regulatory incentives- Green public building requirements

29 states have utility incentives- Loans and rebates- Mandatory Renewable Portfolio Standards

(RPS) and Energy Performance Standards(EPS)

- Voluntary Demand Side Management (DSM)Programs

BENEFITS LEAD TO GOVERNMENT INCENTIVES

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Location: Baltimore, MD– Heating Load: 84,000 BTU– Cooling Load: 36,000 BTU

Conventional Heating Source– High efficiency natural gas furnace – Forced air distribution– $11,000

Conventional Cooling Source– Central air conditioning– Additional $4,000

Geothermal System– 7-ton* ground source heat pump– Rough total system cost of $30,000 (vs. $15,000)– Typically monthly savings on utilities outweighs increased monthly mortgage payment

*1 ton = 12,000 BTU/hour

COST COMPARISON: GEOTHERMAL VS. CONVENTIONAL TECHNOLOGY

GEOTHERMAL OVERVIEW

House Size: 3,500 ft2

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COMPARISON: GEOTHERMAL VS. CONVENTIONAL SYSTEM

GEOTHERMAL OVERVIEW

Data based on Baltimore, MD design parameters using Ground Loop Design Software

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COMPARISON: GEOEXCHANGE VS. CONVENTIONAL SYSTEM

GEOTHERMAL OVERVIEW

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GEOTHERMAL OVERVIEWSUMMARY: BENEFITS OF GROUND SOURCE HEAT PUMP TECHNOLOGY

- Reduced operating costs- Reduced emissions - Low maintenance - Simplicity- Efficiency- Water heating- No auxiliary heat- Low power demand- Packaged equipment- Environmentally friendly

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GEOTHERMAL DESIGNBASIC SYSTEM COMPONENTS AND DESIGN CONSIDERATIONS

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- Most common heat pump type where heating and cooling are required

- Works with forced air distribution

GROUND SOURCE HEAT PUMP

WATER-TO-AIR

BASIC SYSTEM COMPONENTS

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GROUND SOURCE HEAT PUMP

WATER-TO-WATER


- For heating and cooling

- Residential or commercial

- Works ideally with hydronic (water) distribution

- Radiant heating/cooling- Snow and ice melting

- Also works with forced air distribution using hydronic fan coils

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GROUND LOOP PIPES

POLYETHYLENE PIPES WITH FUSED U-BEND


- Fusion-welded single x U-bend - HDPE Material- 3/4”, 1”, 1 1/4” pipes- CTS or IPS dimensions- Fused joints, in field or factory- Two pipes in a bore hole (one loop)

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GROUND LOOP PIPES

CROSS-LINKED POLYETHYLENE (PEXa)


- Continuous Single or Double U-bend - PEXa material- 3/4” or 1” sizes- CTS SDR9 dimensions- No joints in the well or loop- Up to four pipes in a bore hole (two loops)

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CONFIGURATIONS: CLOSED LOOP

Energy Pile Storage Vertical Wells Horizontal Fields

GEOTHERMAL APPLICATIONS

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GEOTHERMAL APPLICATIONSVERTICAL BOREHOLES

- Commonly used in commercial applications- Used in residential applications where space is limited- Approximately 150-200 ft. of borehole per ton of energy required

- This varies across the country with different soil types, water tables, etc.- Typical sizing is 1.5 tones per 300 feet well depth

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- Commonly used in residential applications- Sometimes used in commercial applications where space allows- Approximately 300-400 ft. of trench (600-800 ft. of pipe) per ton of energy required- Variations in trench layout acceptable

GEOTHERMAL APPLICATIONSHORIZONTAL FIELD

Field system alternate variations

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- Commonly used in residential applications- Sometimes used in commercial applications where space allows- Approximately 200-300 ft. of trench (400-600 ft. of pipe) per ton of energy required

GEOTHERMAL APPLICATIONSHORIZONTAL DIRECTIONAL DRILLING (HDD)

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GEOTHERMAL OVERVIEWTHANK YOU!

nc denr geothermal overview presentation · geothermal overview geothermal benefits have helped...

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