Geothermal Heat PumpsA Proven Renewable Energy Technology by

Greg Tinkler, CGD

While Earth travels through Space…

…it Absorbs Energy from the Sun

This natural Energy Collection and Storage System captures nearly 50% of the Solar

Energy falling on Earth…

…thus maintaining a nearly Constant Temperature throughout the year just below the surface

Water is an incredibly efficient medium for transporting Thermal Energy

1 Btu will raise 1 lb (approx. 1 pint) of water up 1 degree Fahrenheit

2,000 lbs of ICE- How many Tons does it take to melt?

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Geothermal Heat Pump Systems combine Sun, Earth, and Water

using proven technology…

… to create “the most energy-efficient, environmentally clean, and cost-effective

space-conditioning system”(according to U.S. EPA 1993)

Geothermal Heat PumpBasic Principles

HOW DOES IT WORK ?

Heat pumps remove or add heat to a building.

The heat removed or added must be rejected to something: Directly to outside air (like your house system) To water, which in turn rejects heat to the

atmosphere via a cooling tower. To water, then to the earth (Geothermal Heat

Pumps) Closed Loop System – not taking water from

the ground9

AVERAGE GROUND WATER

TEMPERATURES

WHICH IS EASIER TO REJECT HEAT TO ?

99 DEGREE AIR OR 72 DEGREE DIRT

The Earth is an Efficient Place to Reject Heat in Summer…

Outdoor air design temperature:98°F in summer

74°F

72°F

Insulating layer of earth

A geothermal heat pump cools the building in summer by rejecting heat into the earth

Delta T = $ to operate!!!

…and is the Source of Stored Heat in Winter…

Outdoor air design temperature:31.5°F in winter

72°F

80°F

Insulating layer of earth

A geothermal heat pump takes heat from the earth during winter and transfers it into the building

Delta T = $ to operate!!!

A geothermal heat pump is connected to a sealed water piping loop buried in the earth near the building

When water exiting the heat pump is pumped through the ground loop, it is naturally warmed (or cooled) by the earth surrounding it

Insulating layer of earth

…using Heat Pump Technology

Geothermal Heat Pump Efficiency

One unit of energy from the grid

Plus:4 units of energy

from the earth

Yields:5 units of energy for the building

500% Efficient

Air In70 F

Air Out100 F

WaterOut44 F

WaterIn

50 F

Compressor

Fan

WaterCoil

Air Coil

Revers ingValve

Expans ionValve

Geothermal Heat Pumps Exchange Heat between Air and Water

$1 Worth of Electricity to Operate the Compressor and Fan

Moves $5 Worth of Heat from the Water

Delivering $6 Worth of Heat into the Air

Heating Mode Shown

Heat can be “pumped uphill”meaning delivered at a highertemperature than the source

$4$4

$1$1

$5$5

Geothermal Heat PumpsHeat or Cool on Demand and also

Produce Hot Water

Operates on the Same Principle as a Refrigerator

Cooling Mode Shown

160F

Air In80 F

Air Out58 F

WaterOut80 F

WaterIn

70 F

Compressor

Fan

WaterCoil

Air Coil

ReversingValve

ExpansionValve

HWIn

90 F

HWOut

120 F

Hot water is produced whenever the unit is operating

$4$4

$5$5

$1$1

Heat Pumps Are All Around Us…

Air conditioners and air-source heat pumps transfer heat from inside houses to the air outside

Refrigerators transfer heat from food into the kitchen

HEAT

BB

B

HEAT

INDOOR COMPONENTS

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Horizontal Units

Vertical Units

Geothermal Heat ExchangerInstallation Methods

Vertical Closed-LoopA pair of pipes with a special U-bend assembly at the bottom is placed into bore holes from 100 to 400 feet deep

Horizontal Closed-Loop A piping array is installed in trenches cut 3 to 5 feet deep and hundreds of feet in length

Surface Water Closed-LoopA piping array is submerged in a pond or lake at least 12 feet deep

Ground WaterOpen-LoopWell water from an underground aquifer is pumped through the geothermal heat pump and then returned to the aquifer or discharged to the surface

Vertical Closed-Loop Installation

DrillingPipe LoopInsertion

Heat Fusing

InsideConnection

TRENCHING & MANIFOLDING

• Well fields

25

Trenching and Manifolding

The Finalized Earth Heat Exchanger

Connecting the wells with each other

The Earth Heath Exchanger is covered with soil. Nothing has changed!

STAGE 3: CONNECTION WITH THE BUILDING

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Main connection to the building

Interior piping network connects all the Water Source Heat Pumps to the EHX

Geothermal Hybrid System - Summer

Heat Pump

Water Pump

Earth Loops

Cooling Tower(ON)

Residential Geothermal Hybrid System

Residential Tax Incentives• Code Sec. 25D. Residential energy efficient property.• (a) Allowance of credit.

In the case of an individual, there shall be allowed as a credit against the tax imposed by this chapter for the taxable year an amount equal to the sum of—

• 6(5) 30 percent of the qualified geothermal heat pump property expenditures made by the tax payer during such year.• (b) Limitations. • (1) Maximum credit.

The credit allowed under subsection (a) (determined without regard to subsection (c) ) for any taxable year shall not exceed—

7 , • (D) $2,000 with respect to any qualified geothermal heat pump property expenditures.• (c) Limitation based on amount of tax; carry forward of unused credit • (1) Limitation based on amount of tax.

In the case of a taxable year to which section 26(a)(2) does not apply, the credit allowed under subsection (a) for the taxable year shall not exceed the excess of—

• (A) the sum of the regular tax liability (as defined in section 26(b)) plus the tax imposed by section 55, over• (B) the sum of the credits allowable under this subpart (other than this section) and section 27 for the taxable year.• (2) Carry forward of unused credit. • (A) Rule for years in which all personal credits allowed against regular and alternative minimum tax. In the case of a taxable

year to which section 26(a)(2) applies, if the credit allowable under subsection (a) exceeds the limitation imposed by section 26(a)(2) for such taxable year reduced by the sum of the credits allowable under this subpart (other than this section), such excess shall be carried to the succeeding taxable year and added to the credit allowable under subsection (a) for such succeeding taxable year.

• (B) Rule for other years. In the case of a taxable year to which section 26(a)(2) does not apply, if the credit allowable under subsection (a) exceeds the limitation imposed by paragraph (1) for such taxable year, such excess shall be carried to the succeeding taxable year and added to the credit allowable under subsection (a) for such succeeding taxable year.

Commercial Incentives• Code Sec. 48. Energy credit.• (a) Energy credit. • (1) In general.

For purposes of section 46 , except as provided in 1 2 paragraphs (1)(B) , and (2)(B) , (3)(B) , and (4)(B) of subsection (c) , the energy credit for any taxable year is the energy percentage of the basis of each energy property placed in service during such taxable year.

• (2) Energy percentage. • (A) In general. The energy percentage is—• (i) 30 percent in the case of—• (II) energy property described in paragraph (3)(A)(i) but only with respect to periods ending before 3 January 1, 2017, 4

• (III) energy property described in paragraph (3)(A)(ii), and• (IV) qualified small wind energy property , and• (ii) in the case of any energy property to which clause (i) does not apply, 10 percent.• (B) Coordination with rehabilitation credit. The energy percentage shall not apply to that portion of the basis of any property which is attributable

to qualified rehabilitation expenditures.• (3) Energy property.

For purposes of this subpart, the term “energy property” means any property—• (A) which is—• (i) equipment which uses solar energy to generate electricity, to heat or cool (or provide hot water for use in) a structure, or to provide solar

process heat, excepting property used to generate energy for the purposes of heating a swimming pool, • (ii) equipment which uses solar energy to illuminate the inside of a structure using fiber-optic distributed sunlight but only with respect to periods

ending before 6 January 1, 2017,• (iii) equipment used to produce, distribute, or use energy derived from a geothermal deposit (within the meaning of section 613(e)(2) ), but only, in

the case of electricity generated by geothermal power, up to (but not including) the electrical transmission stage, 7

• (iv) qualified fuel cell property or qualified microturbine property, 8 9

• (v) combined heat and power system property, 11 12

• (vi) qualified small wind energy property, 14 or• (vii) equipment which uses the ground or ground water as a thermal energy source to heat a structure or as a thermal energy sink to cool a

structure, but only with respect to periods ending before January 1, 2017,

PROJECT TYPES

LIKELY High end single family Multi-family – public or

military Schools Healthcare Hospitality Corporate office LEED/Green Building Owners who prefer simpler

systems

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LESS LIKELYDeveloper buildingsPrivate multi-familyProjects where First Cost is more important than Life Cycle CostsCampuses with a Chilled Water Infrastructure

HOW DOES IT AFFECT ARCHITECTURAL DESIGN?

INSIDE THE BUILDING Plenum space: little or no difference compared to Tower Loop Heat

Pumps, Chilled Water Fan Coils or VAV Box Type Systems Mechanical rooms and shafts: less space than Central Air Handlers

OUTSIDE THE BUILDING Roof: no units on the roof (but can be) No condensing units on the ground No visible loop piping Little affect on finished landscaping , grading & paving

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Electric Utility PerspectiveAnd

CASE STUDIES

Garrett Office BuildingsEdmond, Oklahoma

Garrett Office BuildingsGarrett Office BuildingsAnnual Energy and HVAC Maintenance Costs 2006-2007Annual Energy and HVAC Maintenance Costs 2006-2007

-

0.50

1.00

1.50

2.00

2.50

VAV System Geothermal

$ p

er S

qu

are

Fo

ot

Total

Electricity

Gas

Maintenance

55% Operational Cost Savings55% Operational Cost Savings

Garrett Office BuildingsGarrett Office BuildingsAnnual Energy Use 2006-2007Annual Energy Use 2006-2007

-

10

20

30

40

50

60

70

80

90

VAV System Geothermal

kBtu

per

Sq

uar

e F

oo

t

Total

Electricity

Gas

47% Site Energy Savings47% Site Energy Savings

Garrett Office BuildingsGarrett Office BuildingsAnnual COAnnual CO22 Emissions 2006-2007 Emissions 2006-2007

20

25

30

35

40

45

50

VAV System Geothermal

Lb

s. C

O2

Eq

uiv

alen

t p

er S

qu

are

Fo

ot

Gas

Electricity

28% Carbon Emissions Reduction28% Carbon Emissions Reduction

0

1

2

3

4

5

6

7

8

9

10

Jul-06 Aug-06 Sep-06 Oct-06 Nov-06 Dec-06 Jan-07 Feb-07 Mar-07 Apr-07 May-07 Jun-07

kBtu

per

Sq

uar

e F

oo

t

VAV System

Geothermal

Garrett Office BuildingsMonthly Energy Use

2.0

2.5

3.0

3.5

4.0

4.5

5.0

5.5

6.0

Jul-06 Aug-06 Sep-06 Oct-06 Nov-06 Dec-06 Jan-07 Feb-07 Mar-07 Apr-07 May-07 Jun-07

Wat

ts p

er S

qu

are

Fo

ot

VAV System

Geothermal

Garrett Office BuildingsMonthly Peak Demand

System Performance Comparison

Arnold$0.91

Mosley$1.68

Bozeman$2.27

Bay Haven$0.73

0

0.5

1

1.5

2

2.5

3

Cost per Square Foot

Arnold Mosley Bozeman Bay Haven Washington* Arnold High School - Closed Loop Geothermal System (completed Aug, 2000)

•Mosley High School - Gas Boiler/Chiller System (Updated w/ new equipment 1996)•Bay Haven Charter School – Closed Geo System

•Bozeman Learning Center-All Electric-Gulf Coast Co-Op•Washington Co. – Includes Rouhlac Middle School & Chipley High School Open Geo System

Metered KWH’s Geothermal vs Conventional Fast Food Store

2008

31

17

21

1710

14

1011

10

(Conventional Store Kwh’s Percent more than Geothermal Store)

Geothermal Heat Pumpsare one of the Most Effective

and Deployable…

… producing the lowest carbon dioxide emissions, including all source effects, of all available space-conditioning technologies

(EPA, 1993)

RESOURCES

IT MAY NOT BE ROCKET SCIENCE, BUT USE AN EXPERIENCED TEAM

Consulting Engineers Contractors: installation, testing, monitoring. Can provide

financing. Partner with local contractors for indoor systems. Associations

IGSHPA : www.igshpa.okstate.eduGEOTHERMAL HEAT PUMP CONSORTIUM www.geoexchange.org

ASHRAE www.ashrae.org

Vendors: WaterFurnace, Climate Master, Carrier, Trane, Florida Heat Pump, McQuay,

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