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Design Considerations with Geothermal Heat Pumps (GHP). Introduction The “Big Picture” Background - Commercial Mechanical Systems Benefits of employing GHP in a building project THE GROUND EXCHANGE (GX) – types and factors The Future of GHP Questions.
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Design Considerations with Geothermal Heat Pumps (GHP) • Introduction • The “Big Picture” • Background - Commercial Mechanical Systems • Benefits of employing GHP in a building project • THE GROUND EXCHANGE (GX) – types and factors • The Future of GHP • Questions
Design Considerations with Geothermal Heat Pumps (GHP) • The “Big Picture” • GHP’s are not new technology, proven • GHP’s are EQUIPMENT, the GX is ENERGY • GHP equipment can be employed in most any system that currently exists – it merely makes use of a different energy source • Large scale deployment WILL reduce energy consumption….40-50% of increased electrical demand • Discussion needs to center around the energy side - the GROUND EXCHANGE
Design Considerations with Geothermal Heat Pumps (GHP) • Fundamentals of Building Mechanical Systems • System Architecture – Centralized or Decentralized • Delivery of Energy – Direct or Indirect • Energy Transfer – Air or Radiant • Energy Source – Electricity, Gas, Propane, Fuel oil, etc • Geothermal ground exchange systems • All of the above types of architecture, as well as delivery and transfer of energy can be employed by using GX as an energy source.
Design Considerations with Geothermal Heat Pumps (GHP) Coil Central Boiler Air Handler DIRECT HEATING IN-DIRECT HEATING
Design Considerations with Geothermal Heat Pumps (GHP) Regardless of the system architecture, how the energy is delivered, or how the energy is transferred to the space, the ground exchange (GX) is a viable ENERGY SOURCE for a variety of systems. Sources of ENERGY Combustion of Fossil Fuel Electricity Energy Exchange – e.g. Geothermal
Design Considerations with Geothermal Heat Pumps (GHP) • Benefits of a Geothermal System for Owners • Zoning flexibility • Simplified Controls • Ability to heat and cool from a single unit • Ability to heat and cool different parts of the building at the same time • No visible exterior equipment • Typically less mechanical space required and fewer building penetrations • LOWER ENERGY COSTS
Design Considerations with Geothermal Heat Pumps (GHP) • GX – Horizontal Loop Considerations • Fairly inexpensive for small loads (residential) • Takes up large ground area, virtually impossible for larger installations • Not as efficient (ground temperatures vary at 7 feet) • Variable exchange rates with different soils’ • Disruptive to site, very expensive if backfilling is structured • Really only viable for smaller installations with open ground available – proper design imperative
Design Considerations with Geothermal Heat Pumps (GHP) • GX – Vertical Loop Considerations • Requires less ground, but still must have available site space for fairly large bore field for larger installations • Expensive, especially without qualified drillers • More efficient with more stable temperatures • Variable exchange rates with different soils’ • Disruptive to site, needs “manifolding” of vertical loops • Good option where groundwater is deep, poor quality, or unavailable • Proper design imperative
Design Considerations with Geothermal Heat Pumps (GHP) • GX – Ground Water Sourced Considerations • Requires virtually no ground – can be installed in urban environments • Usually the least expensive, per ton, if sufficient water is available (Applicable to many areas in Montana) • Most efficient with very stable temperatures • Can be used with open or closed loop systems • Need to watch water quality and depth to aquifer • Does not “use” water, just borrows it. • Does not require specialty installation for the GX – needs proper design, however.
Design Considerations with Geothermal Heat Pumps (GHP) Case Example – Lincoln County Credit Union, Libby, MT • Open Loop GX • Closed internal loop • Includes Air system in office space • Radiant floor lobby heat • Energy Recovery Ventilation • Highly zoned space • Simple controls
Design Considerations with Geothermal Heat Pumps (GHP) • Future of GHP • It’s about the energy, the GX, the single largest factor that makes GHP non-competitive • Utility type infrastructure? (USDA/RUS Loans) • With more education, lowered misunderstandings and misapplication of GHP’s • Higher usage will lower unit cost and increase efficiencies • Will be instrumental in lowering future demand for electricity – should it get benefits of renewable power • Lower hurdles, particularly for well drilling and permitting
Design Considerations with Geothermal Heat Pumps (GHP) QUESTIONS? Contact: Shane Jackola, PE, LEED AP Jackola Engineering and Architecture, PC 2250 Hw 93 South Kalispell, MT 406.755.3208 shane@jackola.com