USGBC - Cascadia Chapter | 14 September 2005 geo exchange systems (ground coupled hydronic heat pump hvac systems) BLRB Architects , p.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 G e o E x c h a n g e S y s t e m s
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) G e o E x c h a n g e S y s t e m s
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) G e o E x c h a n g e S y s t e m s
Heat Pump Systems vertical ground-coupled CLOSE HEADERS HIGH DENSITY POLYETHYLENE PIPE (3/4" TO 1-1/2" DIAMETER) 15' TO 20' U-BENDS G e o E x c h a n g e S y s t e m s
Heat Pump Systems conventional horizontal ground-coupled REVERSE-RETURN HEADERS BACKHOE EXCAVATION 5' Min. 6' 4' TRENCHER 3/4" TO 1-1/2" INSTALLATION HIGH DENSITY POLYETHYLENE PIPE G e o E x c h a n g e S y s t e m s
Heat Pump Systems slinky coil ground-coupled BACKHOE TRENCHER INSTALLATION INSTALLATION 5' MIN 5' MIN 3/4" HIGH DENSITY POLYETHYLENE PIPE COILS OR POLYBUTYLENE G e o E x c h a n g e S y s t e m s
Kapowsin Elementary School geoexchange project example Opening: Fall 2003 Owner: Bethel School District Kapowsin Elementary School 10412 264 th Street East | Graham, Washington G e o E x c h a n g e S y s t e m s
Kapowsin Elementary School BLRB geoexchange project example 1st Place Winner of the CEFPI WA Chapter Competition “Why We Love Our School” G e o E x c h a n g e S y s t e m s
Kapowsin Elementary School site plan G e o E x c h a n g e S y s t e m s
Kapowsin Elementary School site with geoexchange G e o E x c h a n g e S y s t e m s
Kapowsin Elementary School 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) G e o E x c h a n g e S y s t e m s
Kapowsin Elementary School partial mechanical site plan G e o E x c h a n g e S y s t e m s
Kapowsin Elementary School slinky ground heat exchanger G e o E x c h a n g e S y s t e m s
Kapowsin Elementary School ground heat exchanger piping trench G e o E x c h a n g e S y s t e m s
Kapowsin Elementary School supply & return header mains G e o E x c h a n g e S y s t e m s
Kapowsin Elementary School heat pump piping system G e o E x c h a n g e S y s t e m s
Kapowsin Elementary School hot water tank preheat (∆ ± 10°F) G e o E x c h a n g e S y s t e m s
Midland Elementary School geoexchange project example Opening: Fall 2003 Owner: Franklin Pierce School District Midland Elementary School 2300 105 th Street | Tacoma, Washington G e o E x c h a n g e S y s t e m s
Midland Elementary School geoexchange project example G e o E x c h a n g e S y s t e m s
Midland Elementary School site plan G e o E x c h a n g e S y s t e m s
Midland Elementary School site with geoexchange G e o E x c h a n g e S y s t e m s
Midland Elementary School 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 G e o E x c h a n g e S y s t e m s
William Wiley Elementary School geoexchange project example Opening: Fall 1999 Owner: Richland School District William Wiley Elementary School 2820 South Highlands Blvd. | West Richland, Washington G e o E x c h a n g e S y s t e m s
William Wiley Elementary School site plan G e o E x c h a n g e S y s t e m s
William Wiley Elementary School site with geoexchange G e o E x c h a n g e S y s t e m s
William Wiley Elementary School 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 G e o E x c h a n g e S y s t e m s
William Wiley Elementary School 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 Mechanical Room Floor Plan (No Boiler, Cooling Tower or Heat Exchanger/Fluid Cooler) G e o E x c h a n g e S y s t e m s
William Wiley Elementary School 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 Mechanical Loft Electric Preheat Coils (Not in Picture) G e o E x c h a n g e S y s t e m s
William Wiley Elementary School in rooms • Occupancy Sensors that Turn Off Lights and Fresh Air when No Occupancy • CO 2 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 G e o E x c h a n g e S y s t e m s
William Wiley Elementary School 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 G e o E x c h a n g e S y s t e m s
Beaver Lake Middle School geoexchange project example Opening: Fall 1994 Owner: Issaquah School District Beaver Lake Middle School 25025 SE 32 nd Street | Issaquah, Washington G e o E x c h a n g e S y s t e m s
Beaver Lake Middle School 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 G e o E x c h a n g e S y s t e m s
Beaver Lake Middle School site plan G e o E x c h a n g e S y s t e m s
Beaver Lake Middle School site with geoexchange G e o E x c h a n g e S y s t e m s
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? G e o E x c h a n g e S y s t e m s
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 G e o E x c h a n g e S y s t e m s
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 G e o E x c h a n g e S y s t e m s
resources GHPC Geothermal Heat Pump Consortium (202) 558-7175 www.geoexchange.org AEEES Association for Efficient Environmental Energy Systems (530) 750-0135 info@aeees.org G e o E x c h a n g e S y s t e m s
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