ClimateMaster Geothermal What, When, Where, & How.

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ClimateMasterGeothermal

What, When, Where, & How

What IsWhat Is Geothermal?Geothermal?

Boiler/Tower Boiler/Tower SystemsSystems

Ground-SourceGround-Source(Geothermal)(Geothermal)

Several Variations of Geothermal

Vertical Closed LoopHorizontal Closed LoopHybrid (Geo and Tower/Boiler)Lake Closed LoopClosed to the AquiferStanding Column Well

Vertical Loop System

Verticals

One Pair Two Pair Series/Parallel One Pair

When Loops areshallower than

one ton per loop

Vertical Loops

• 3/4” pipe - One vertical bore per ton. One circuit and 3 gpm flow per ton.

• Many areas require bentonite grouting• Some locales restrict drilling• Bore per ton

– Cold climates 150 ft per ton– Warm climates 230 ft per ton

Horizontal Loop System(Slinky shown)

Horizontal Loop Types

2 ft 2 ft

Back-Hoe LoopsTwo-Pipe Four-Pipe Six-Pipe

Trenched Loops

Two-Pipe Four-Pipe Extended Slinky

Horizontal Loops

• Limited tonnage due to land area• Backhoe or trench excavation. In areas with

any rock typically backhoe only.• 1 circuit and 3 gpm flow per ton w/ 3/4” pipe• Pipe per ton

– Cold Climates - 400 to 1000 ft– Warm Climates - 700 to 1800 ft

Ground Source - Closed Loops

• Benefits– Lower maintenance– No water requirements

• Hurdles– Requires land space– First cost

Ground Loop

• 3 gpm flow per ton of cooling• 1 circuit or flow path per ton of cooling w/ 3/4” loop pipe• Loop Temperatures

– 40 - 90 deg F

Hybrid Systems

Ground Loop/TowerGround Loop/BoilerBenefits:

– Off Peak Operation

– Low First Cost

Hybrid Loops

Lake Loop System

300 ft slinky coilper ton

4 ft between coils

ConcreteBlocks for

weight

Nylon Cable Tiesto secure blocks

300 ft coil per tonseparated by scrap

Traditional Coiled Pond Loop- Southern Climates

High Efficiency Slinky/Matt PondLoop - Northern Climates

Heavy Duty PlasticSafety matting

8-10 Bricks forweight

Reverse ReturnHeader

Nylon Cable Tiesto secure Netting

and bricks

3 foot separation

Pond Loops

• Least expensive ground loop• Minimum 300 ft2 per ton and 9 feet deep• In north need ice cover for operation (no

aeration). Utilizes 39 degF water temp.• Pond should be within 300’ of structure• 300 ft Pipe per ton

Closed to the Aquifer Systems

Ground Water - Plate Frame HX • Benefits

– Lower first cost– No land requirement– Isolated internal loop via HX

• Hurdles– Requires annual HX maintenance– Requires injection well– Typically used only with more than 4 total units

Standing Column Well

Ground Water - Direct Use

• Benefits– Lowest first cost– No land requirement

• Hurdles– Requires clean water and more maintenance– Getting rid of water can be difficult– Larger pump and pressure tank– Typically used only with 3 or less total units

Heat of extraction/rejection

Moving Heat to Water or Air

water refrig airorororor

Heat of extraction

HEATING

water refrig air

WORK 1.08 kw=3.680 kbtu/hr

11.6 kbtu/hr 15.3 kbtu/hr

COP = 15.3/3.68 = 4.15

Heat of rejection

COOLING

water refrig air

15.2 kbtu/hr

0.95 kw=3.2 kbtu/hr

12.0 kbtu/hr

EER = 12.0/0.95 = 12.6

Refrigeration Circuit Overview

Compressor

ExpansionDevice

To Loop Source

ReversingValve

AirCoil

Suction

DischargeCoax

Refrigeration Circuit OverviewCooling Mode (GS036)

Compressor

ExpansionDevice

To Cooling Tower

ReversingValve

AirCoil

Suction

DischargeCoax

155 F218 psi

80 F 60 F

60 F76 psi

92 F 9gpm

a) Lvg air coil temp is lower than ent air coil temp is due to pressure drop through air coil.a) Lvg air coil temp is lower than ent air coil temp is due to pressure drop through air coil.b) Suction temp at compressor is higher than lvg air coil temp because vapor continues b) Suction temp at compressor is higher than lvg air coil temp because vapor continues to superheat as it travels back to compressor.to superheat as it travels back to compressor.

Refrigeration Circuit OverviewHeating Mode (GS036)

Compressor

ExpansionDevice

To Boiler

ReversingValve

AirCoil

Suction

DischargeCoax

168 F248 psi

70 F 107 F

66 F86 psi

59 F 9gpm

How didHow did GeothermalGeothermal

Gain MomentumGain Momentum??

HistoryBehind

Geothermal

Late 70’s-Early 1980’s

• Energy crisis: Fossil fuel shortages and price shocks

• Dependence shifts to electricity• Opportunity builds for geothermal technology• Technical competence for geothermal water

source heat pumps develops in the industry

Mid 1980’s

• Electric utilities experiencing “peak demands”• DSM (demand side management) becomes a

strategic planning tool• Extensive monitoring reveals geothermal

efficiency and market potential• Geothermal becomes recognized as DSM

planning tool

Late 1980’s

• Performance Standards established for geothermal systems

• Support grows from regulators, research groups and utilities

• Substantial performance in utility DSM programs

• A proven technology competitive with conventional fuels

Early 1990’s

• Geothermal systems increase in performance and functionality

• EPA, DOE, EPRI (Electric Power Research Institute), NRECA (National Rural Electric Cooperative Assoc), EEI (Edison Electric Institute) recognize potential for geothermal

• Utility geothermal DSM programs begin implementation

Mid 1990’s

• Geothermal recognized as key technology to reduce greenhouse gases

• EPA and DOE release reports confirming industry growth potential

• Government, utility, and industry consortium formed to assist in the development of the geothermal market

Late 1990’s-Year 2000

• Geothermal becomes recognized as a major renewable energy source on an international scale

History of Ground Source Heat Pumps Installations

• Based upon water source heat pump from Florida of 1950’s

• Ground loop development using iron and copper loops 1930’s and 40’s. PB and PE pipe made viable in late 1970’s.

• Three regions of development in 1979:– OSU - J. Bose, J. Partin, G. Parker– Ft Wayne, IN - Dan Ellis– Ontario - Dave Hatherton

Antifreeze Materials

• Methanol - least expensive and good heat heat transfer

• Ethanol - More expensive and best heat transfer

• Propylene glycol - non-toxic and expensive, but lowest heat transfer

Pipe and Fittings

Pipe and Fittings Material

• High Density polyethylene (HDPE )pipe developed for natural gas distribution industry

• Socket or Butt heat fusion joints are stronger than the pipe wall itself

• 3/4, 1, 1-1/4, 1-1/2, and 2” sizes common• Coils and straight lengths• Many fittings available in tee’s, elbow’s, and

couplings

Loop Design

Loop TerminologyHeader

Supply/ReturnLines

Loop/Heat Transfer Field

Loop Terminology (cont.)

Manifold

Supply/ReturnLines

To Earth Loop

To Building

Supply/Return Isolation Valves

Loop Design

• Loop style and total trench/bore length obtained from software design

• Goal is 2.5 - 3 gpm flow per ton of capacity (minimum of 2.25 gpm)

• Loop circuiting is designed for:– Low pressure drop– Good heat transfer

• Headers are piped in reverse return to even out pressure drop in parallel circuits

• Option 1 - Redundant Alternate - Size single pump to handle complete circulation install duplicate redundant pump in parallel and control alternately

• Option 2 - Redundant Staged - Install two pumps in parallel that can handle load and stage them with alternating controls

• Option 3 - Variable speed pumps with solenoids at each unit

• Option 4 - Distributed pumping - Install pumps at each heat pump with single pipe system and continuous circulation

Circuit Design rules

• 1 circuit per ton of capacity in 3/4” • 2.5 - 3 gpm per ton of capacity

Header Design

Circuit 4 Circuit 3 Circuit 2

1 1/4" IPS PE Pipe

3/4" IPS PEPipe

1 1/4” x 1 1/4" x 3/4"IPS PE Tee

11/4" x 3/4" x 3/4"IPS PE Tee

3/4" x 3/4" x 3/4"IPS PE Tee

3/4" IPS PEPipe

Circuit 5

Design Do’s and Don’ts

• Design air scoop/trap between building and earth loops to entrap air stemming from wshp maintenance

• Utilize Mechanical room or outside pit to house manifold of supply/return lines with individual shut-offs and main loop to building

• Ensure equipment is rated for temperature range of loop WLHP, GWHP or GLHP

• In hybrid design size loop for heating load and tower for extra cooling required

Flushing

• Flush exterior loop first using system pumps. • Flush supply/return one at a time.• Flush interior loop with exterior isolated so as

not to move air to earth loop

Antifreeze

• Antifreeze to 15 deg F below coldest loop temperature expected

• Always add alcohols below water level to reduce fumes

• Check antifreeze concentrations using the specific gravity charts

EquipmentEquipment

Components Allowing Geothermal

Copeland UltraTech™two-stage unloadingscroll compressor

Oversized lanced fin / rifled tube refrigerant-

to-air coil

Insulated Refrig Circuit

Large coaxial refrigerant-to-water

heat exchanger Bidirectional TXV

Ground source versus air source

• Water has better heat transfer than air• Improved low temp heating capacity• Lower peak demand• Outdoor ambient conditions, damage, and

vandalism• Noisy and unsightly outdoor unit• Better dehumidification• Higher efficiencies

ARI Ratings Summary

• ARI/ISO/ASHARE 13256-1 Ground loop heat pump– Based upon typical extreme loop temperatures– Htg 32 degF and clg 77 degF

Lincoln, NE school district compared leading systems for 3 new schools:

Comparative Analysis of Life-Comparative Analysis of Life-Cycle Costs of Heat Pumps Cycle Costs of Heat Pumps

System 150 Tons $/sq. ft.

Geothermal WLHP $1,021,257 $14.66

Air Cooled Recip Chiller/VAV $1,129,286 $16.21

Water Cooled Cent Chiller/VAV $1,164,268 $16.71

• Note: Air Cooled Chiller is 1kw/ton. Water Cooled Chiller is 0.6kw/ton. Vertical Bore Loop Field cost is $2.50 included in the Geo WLHP cost.

Garrett Office BuildingsEdmond, Oklahoma

Geothermal Building20,000 Sq. Ft.

VAV Building15,000 Sq. Ft.

Floor 2 Conference

Floor 2 Private Office

Floor 2 Open Office Space

Geothermal BuildingFloor 2 Heat Pump Zoning

HP-8 HP-11

HP-15 HP-14

HP-9,10

Loop Field Overview

Geothermal BuildingLoop Field Site Plan

LoopField

Details

2” PE Zone Supply Header - Return Similar3/4” PE bore piping back toheader

Notes:- 40 bores on 20 foot centers each with 3/4” PE pipe- Short header manifold in center of each loop zone of 10 bores- Each bore must have the same overall pipe length for balanced flow

(Coil excess piping in the header trench)- Loop zone supply and returns done in same fashion- Bores must be grouted when completed

Short headerlocation

Typical bore250 ft deep

Geothermal Mechanical

GeothermalMechanical

3” Copper

2” PE typical

Heat PumpSupply

Heat PumpReturn

Expansion

AirSeparator

125 GPM @ 70’PumpsPrimary/Standby

Ground LoopSupply

Ground LoopReturn

Charging

Bypass

Pressure Reducer/Relief

Backflow Preventor

3/4”Air Vent

Floor 1 Heat Pump Piping

Garrett Office BuildingsHighway View

Geothermal BuildingRoof View

VAV BuildingRoof View

VAV BuildingCentral Air Handler

VAV BuildingAir-Cooled Condensing Unit

VAV BuildingBoiler Room

Month Gas Mcf Elec kWh Gas Mcf Elec kWhJan-00 36.2 12,400 0.0 9,920 Feb-00 21.0 14,720 0.0 10,880 Mar-00 6.9 13,600 0.0 9,960 Apr-00 4.3 15,760 0.0 10,120 May-00 3.5 17,920 0.0 11,600 Jun-00 4.2 18,560 0.0 12,400 Jul-00 3.2 21,280 0.0 13,120 Aug-00 3.2 23,520 0.0 14,480 Sep-00 3.2 18,720 0.0 11,120 Oct-00 11.2 16,080 0.0 9,840 Nov-00 21.9 12,720 0.0 10,360 Dec-00 69.4 13,600 0.0 13,600 Total 188.2 198,880 0.0 137,400

$ Cost 1,882 $ 17,899 $ $ 10,992 $

$/ft^2

VAV 15,000 ft^2 Geothermal 20,000 ft^2

1.32 0.55

Garrett Office Buildings 2000 Energy Consumption

Garrett Office Buildings2000 Energy Consumption Profile

Garrett Office BuildingsInstallation Costs

• Geothermal System circa 1998– Complete exterior loop, mechanical room,

interior PE piping, flushing and unit startup, heat pumps, duct work, exhausts, MUA system, timeclock-based controls

– $128,700 ($2,574 per ton)

• VAV System circa 1987– air-cooled condenser, VAV air handler, boiler,

VAV boxes with reheat coils, economizer, electronic controls

– $100,000 ($2000 per ton)– costs per building owner do not include structural

or architectural

ClimateMasterGeothermalHeat Pumps

ClimateMaster Geothermal What, When, Where, & How.

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