Geothermal Heat Pump

Systems

Earth is a Vast Solar Collector

U.S. Underground

Temperatures

72°F

62°F

Geothermal heat pumps

transfer underground heat into

the building to provide heating

The Earth is a Source

of Heat in Winter…

Outdoor air temperature: 5°F

Outdoor air temperature: 100°F

72°F

62°F

Geothermal heat pumps

transfer heat from the building

to the earth to provide cooling

… and an Efficient

Place to Reject Heat

in the Summer…

Geothermal heat pumps

circulate water through a

sealed underground piping

loop where it is naturally

warmed (or cooled) by the

earth

…using Heat

Pump Technology

Geothermal is not new technology

Geothermal is not new technology

Geothermal is not new technology

• Ground loop development using iron and copper

loops in the 1940’s. PB and PE pipe made viable in

late 1970’s.

• Oklahoma State University began involvement in

late 1970s driven by J. Bose, J. Partin, and G. Parker

Heat Pumps

• Heat pumps “move” energy from one location to

another, instead of creating heat by burning fossil fuels,

such as a gas furnace does. -- (like your refrigerator).

• Geothermal Heat Pumps use the earth or well water to

provide heating, cooling and hot water for your home.

• A geothermal heat pump “moves” energy to/from the

ground, eliminating the outdoor equipment associated

with ordinary heat pumps or air conditioners.

Heat Pump Operation• Geothermal heat pumps consist of four

circuits:

– Distribution circuit• The system that distributes the conditioned air or

water solution throughout the home or building and returns it to the unit.

– Refrigerant circuit• A sealed and pressurized circuit of refrigerant

including compressor, expansion valve, water-to-refrigerant heat exchanger(s), air coil, reversing valve. The refrigerant is either R-22 or R-410A.

Heat Pump Operation

• Geothermal heat pumps consist of four circuits:

– Ground loop circuit• The piping system buried in the ground has fluid

that is circulated by pumps to and from the geothermal unit.

– Hot water circuit• Domestic water can be heated in a geothermal unit

with a device called a desuperheater. A piping connection is made from the geothermal unit to the water heater.

Heat Pump Operation

• The Four Circuits in a Geothermal Heat

Pump

Distribution Circuit

Earth Loop Circuit

Refrigeration Circuit

Hot Water Circuit

= Flow of Energy

(Heat)

Heat Pump Operation• Each of these circuits is closed and sealed

from the others—there is no direct mixing.

• However, heat energy does transfer from the refrigeration circuit to the other three circuits.

• The refrigerant flow will change direction when the unit changes modes (heating or cooling).

Heating Mode Operation

Cooling Mode Operation

The Basic Refrigeration CycleCompressor

CondenserEvaporator

TXV

High Pressure

Vapor State

High Pressure

Liquid State

Low Pressure

Liquid State

Low Pressure

Vapor State

The Refrigeration Cycle

• Heating Mode Operation

The Refrigeration Cycle

• Cooling Mode Operation

Free Energy

• Geothermal Heat Pumps use only a small amount of

energy to capture a large amount of FREE energy from

the earth.

Equipment Performance Ratings

• ARI has designated the efficiency ratings for

water-to-air heat pumps as:

– Energy Efficiency Ratio (EER)

• EER = BTU output divided by power watt input

• For cooling operation under steady state test conditions

– Coefficient of Performance (COP)

• COP = BTU output divided by BTU input

• For heating operation under steady state test

conditions

Geothermal Performance Comparison

0

5

10

15

20

25

30

Cooling Efficiency (EER)

New Geothermal Unit

Previous Geothermal Unit

High Efficiency AC or HeatPump

Ordinary Air Conditioner orHeat Pump

Geothermal Performance Comparison

0.0

0.5

1.0

1.5

2.0

2.5

3.0

3.5

4.0

4.5

5.0

Heating Efficiency (COP)

New Geothermal Unit

Previous Geothermal Unit

Heat Pump

High Efficiency Gas/Propane

Furnace

Ordinary Gas/Propane Furnace

Loop Types• Closed Loop (w/ antifreeze)

– Horizontal

– Vertical

– Pond

• Open Loop

– Well Water

Well Water

(Open Loop)

Uses

existing well

Requires 1.5 gpm/ton

Horizontal Loop

10 ft.

3 feet

2 feet

5- 6 feet

2 feet

2- Pipe Horizontal

Typically 3-4 trenches, 250 feet long each

10 ft.

3 feet

2 feet

5- 6 feet

2 feet

4- Pipe Horizontal

Typically 2 trenches, 180 feet long each

10 ft.

3 feet

2 feet

5- 6 feet

2-3 feet 1 foot

6- Pipe Horizontal

Typically 1 or 2 trenches, 120 feet long each

Horizontal 4 & 6 Pipe Loops

Typically 3 or 4 trenches, 100-150 feet long each

10 ft.

5- 6 feet

2-3 feet

Slinky

Horizontal Slinky Loops

Horizontal Bore Loops

Typically 3-4 bores, 200 feet long each

Vertical Loop

10 – 15 feet

5- 6 feet

Side View

120 – 150 feet

Vertical Loop

Typically 3 to 5 bore

holes, 130 feet deep

each

Vertical bore without backfill

Vertical Loop/Grouted

Bentonite

Grout backfill

Geothermal pipe

U-Bend

used for

Vertical

Loops

Vertical Loop

Drilling

Use drilling rig

like ones used

for water well

drilling.

Pond Loop

Minimum ½ acre,

8 ft. deep

Spacers allow

for more

circulation

around pipes

Top View

Side View

Typically 3 to 5 coils,

300 feet long each

Horizontal Pond/Lake Loops

Slim Jim Lake Plate Heat Exchanger

Racked Loops

Position, Fill & Submerge

Early Systems

1-Stage Equipment

• Either ON or OFF

• Short cycling

• Ineffective Humidity Control

• Temperature fluctuations

• 12-15 EER 3.0 COP

Current Technology

• Variable Speed ECM Blowers

• 2-stage compressors

• 1-stage loop pumps

• Big improvement in efficiency and comfort

• 30 EER, 5 COP

Current GHP Controls

Circa 1990

14 wires

9 wires

Newest Technology

• Variable Speed ECM Blowers

• Variable Speed Compressors - Inverters

• Variable Speed ECM Loop Pumps

• 100% DHW with “smart tank” and 2nd HEX

• 45-50 EER 5.3 COP

Smart Sensors

Smart Valves

Electronic Expansion Valves Are

Controlled By Steps

• The control board looks at refrigerant

temperature and opens or closes the valve

in steps.

• In Units that are multi function a second

EEV and be driven 100% closed forcing

refrigerant down another path.

EEV Position Steps

Variable Speed Compressor

The basic operation is similar to our ECM and Magna

pumps. The AC power input is converted or rectified to

DC power. The DC power is then rapidly switched on

and off through PWM to create a 3-phase sine wave

whose frequency and output voltage is adjusted to vary

the speed of the compressor. The board also includes an

off board inductor and capacitor used for power factor

correction and to store up DC bus voltage.

How the Inverter Works!

Variable Speed Pump

Grundfos Variable Speed Pump

Advanced Heat Exchangers

Micro-Channel Air Coils

Micro-Channel Air Coils

Micro-Channel Air Coils

Communicating GHP Controls

4 wires2-way com

$ less

Launched 2011

Can see real time operation

Real time operation

Operations

Operations

Operations

Reports from Homeowner port

Homeowner port

Homeowner weather

Summary

• Newest systems are even more efficient

• Up to 30% less energy than current models

• More even temperature improves comfort

• Perfect for zoned systems

• More flexibility with 100% DHW

Questions?