geo USGBC - Cascadia Chapter | 14 September 2005 exchange ...blrb.com/images/pdf/GeoExchange...

geoexchange(ground coupled hydronic heat pump hvac systems) systems

BLRB Architects, p.s.

USGBC - Cascadia Chapter | 14 September 2005

G e o E x c h a n g e S y s t e m s

what is geoexchange?

• A water source heat pump system, designed to exchange heat energy with the earth.• A Geoexchange System has 4 components: • A Ground Loop Heat Exchange Piping - In Ground • Fluid Pumping System and Headers - In Central Mechanical Room • A Geoexchange Heat Pump(s) - In Mechanical Space • Conditioned Air Distribution System - Above or Below Space Served

• It can simultaneously provide: • Heating • Cooling • Hot Water


what are the benefi ts?

• Reduced Energy Costs → 20 to 60%• Reduced Maintenance Costs → 30 to 50%• Reduced Water Consumption → ± 20%• No Exposed Outdoor Equipment• Simultaneous Heating and Cooling • Improved Comfort → Individual Room Control• Quieter Operation (Mech. Attic Use, No Cooling Tower)


geoexchange benefi ts

• Reduced Air Quality and Fire Safety Issues

• Smaller Mechanical Room

• Reduced Ductwork/Decentralized Design

• Makes Hot Water

• Utility Peak Power Reduction

• Lowest life Cycle Costs (LCC)


Heat Pump Systems

CLOSE

HEADERS

15' TO20'

HIGH DENSITY

POLYETHYLENE

PIPE (3/4" TO 1-1/2"

DIAMETER)

U-BENDS

vertical ground-coupled


Heat Pump Systems

conventional horizontal ground-coupled

5' Min.

BACKHOE

EXCAVATION

3/4" TO 1-1/2"

HIGH DENSITY POLYETHYLENE PIPE

6' 4'

TRENCHER

INSTALLATION

REVERSE-RETURN

HEADERS


Heat Pump Systems

slinky coil ground-coupled

BACKHOE

INSTALLATION

TRENCHER

INSTALLATION

5' MIN 5' MIN

3/4" HIGH DENSITY

POLYETHYLENE PIPE COILS

OR POLYBUTYLENE


Kapowsin Elementary School

geoexchange project example


Opening:Fall 2003

Owner:Bethel School District

10412 264th Street East | Graham, Washington



BLRB geoexchange project example

1st Place Winner of the CEFPI WA Chapter Competition“Why We Love Our School”



site plan



site with geoexchange



geoexchange concepts at Kapowsin

• Trench System Using Slinky Pipe Under Playfields

• Trench Area is About 215% of Floor Area

• GeoExchange System Provides Domestic Water Preheat

• Trenches Used to Enhance Surface Drainage at Playfield

• Additional Cost - Minimal or None at All (Puget Sound Energy Grant of $35,000 Received)



partial mechanical site plan



slinky ground heat exchanger



ground heat exchanger piping trench



supply & return header mains



heat pump piping system



hot water tank preheat (∆ ± 10°F)


2300 105th Street | Tacoma, Washington

Midland Elementary School



Opening:Fall 2003

Owner:Franklin Pierce School District



site plan



geoexchange concepts at Midland

• Trench System Using Slinky Pipe Under Playfields and Bus Loop

• Trench Area is About 195% of Floor Area

• Space Limitations Require Use of Supplemental Boiler, but No Cooling Tower Required

• Additional Cost of ± $100,000 Funded by School District



William Wiley Elementary School

Opening:Fall 1999

Owner:Richland School District

2820 South Highlands Blvd. | West Richland, Washington




site plan



geoexchange concepts used at Wiley

• 144 Wells, 225 Feet Deep• Located Under Playfield• Spaced 15 Feet Apart• Well Area is About 44% of Floor Area• Each Well has 3/4 Inch Polyethylene Supply and Return Pipes Connected to a 2 Inch Header• Fluid is Water with 15% Methanol Solution and Other Typical Treatment Chemicals• Additional Cost of ± $190,000 Funded by a No Interest Loan from Benton Rural Electric



mechanical room

• Supply Header (Wells to Building)

• Return Header (Building to Wells)

• Water Treatment System

• Variable Speed Pumps (2)

• Electric Water Heaters (2) → Independent of GeoExchange System

(No Boiler, Cooling Tower or Heat Exchanger/Fluid Cooler)

Mechanical Room Floor Plan



mechanical lofts above corridors & toilet rooms

• Supply Air

• Return Air

• Extended Range Hydronic Heat Pumps with Filters

• Relief Air at Soffits

• Fresh Air Supplied by (3) Large Soffit Grilles with Filters and Electric Preheat Coils (Not in Picture)

Mechanical Loft



in rooms

• Occupancy Sensors that Turn Off Lights and Fresh Air when No Occupancy

• CO2 Sensors to Control Fresh Air in Large Spaces

• Zoned Light Switching Coordinated with Daylighting

• Daylighting Sensitive Dimming in Library

• Electronic Control at Toilet Room Fixtures



other concepts

• Building Orientation

• Use of Daylight • 75% of Spaces are Daylighted

• Building Envelope Insulation and Compactness

• Natural Ventilation via Operable Windows

• Electrical System Load Shedding


Beaver Lake Middle School



Opening:Fall 1994

Owner:Issaquah School District

25025 SE 32nd Street | Issaquah, Washington



geoexchange concepts at Beaver Lake

• Trench System with Straight Pipe

• Pipes Located Under Playfields and Some Parking Areas

• Trench is About 240% of Floor Area

• Additional Cost of ± $300,000 Funded by a Puget Power Grant



site plan


other considerations

• Building and Site Environment Requirements • Is Heating and Cooling Required? • Is Antifreeze Recommended?• Maintenance and Operation • On-Staff Expertise• Site Area • Wells or Trenches Take Space• Subsurface Conditions • Are the Soils Conductive? • Use of Conductive Grout • Are Soils Constructible?• Coordination with Utilities • Potential for Conflicts or Enhancements Requires Special Mechanical, Civil and Landscape Coordination• Grants Available?


lessons learned

• Commission the System with an Agent who Understands the System• Train Maintenance & Operations Staff • Monitor Energy Use and Report to A/E and Commissioning Agent• Ongoing Training of New Staff• Understand that Individual Adjustments may Affect Entire System - Usually for the Worst • Flow • Deadband • Need for Recommissioning

• Recommission System if Necessary


design team for projects discussed

Architect BLRB Architects

Mechanical/Electrical Tres West Engineers

Structural Putnam Collins Scott Associates

Civil AHBL, Inc. (Kapowsin Elementary School)

Sitts & Hill Engineers (Midland Elementary School and Beaver Lake Middle School)

J.U.B. Engineers (Wiley Elementary School)

Landscape Lynn William Horn & Associates


resources

GHPCGeothermal Heat Pump Consortium(202) 558-7175www.geoexchange.org

AEEESAssociation for Efficient Environmental Energy Systems(530) [email protected]

geo USGBC - Cascadia Chapter | 14 September 2005 exchange ...blrb.com/images/pdf/GeoExchange...

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