1 Geothermal Heat Pump Systems Geothermal Heat Pump Systems Being Green by using the Ground Being Green by using the Ground Presented by: Warren (Trey) Austin, Warren (Trey) Austin, PE, CEM, CGD, LEED PE, CEM, CGD, LEED - - AP AP Geo Geo - - Energy Services, LLC Energy Services, LLC
33
Embed
Geothermal Heat Pump Systems - BCxA · GeoExchange Systems CV Air Units Horizontal HP Vertical HP Console HP Rooftop HP Hydronic Units WW HP. 11 Cost and Paybacks Installation cost
This document is posted to help you gain knowledge. Please leave a comment to let me know what you think about it! Share it to your friends and learn new things together.
Transcript
1
Geothermal Heat Pump SystemsGeothermal Heat Pump SystemsBeing Green by using the GroundBeing Green by using the Ground
What is the difference between geothermal, ground-source or GeoExchange?Where does the energy come from?What makes ground-source heat pumps energy efficient?How does it heat/cool?How much does it cost?What are the O&M costs?Are there rebates or grants?What are the applications?
Most Often Asked QuestionsMost Often Asked Questions
3
Geothermal 101Geothermal 101Terminology
GeoExchange- General term that groups all aspects of the technology and industry together
Ground Source Heat Pump- A heat pump the uses the earth or ground as a source for heat of absorption or heat of rejection
COP- Coefficient of Performance; Rating for Heating Mode- DHW Heating Only for our case
EER- Energy Efficiency Ratio; Rating for Cooling Mode
4
Geothermal 101Geothermal 101Terminology Continued
BoreholeHDPEGrout
Ground Thermal Conductivity
dtdTkq ground=&
5
Answers to Common QuestionsAnswers to Common QuestionsWhat is the difference between Geothermal and Ground-Source?
Geothermal is the typically associated with a direct-use application of high temperature ground water- ACTIVEGround-source is a term that means you are using the near constant temperature of the earth as a heat sink or heat source- PASSIVE
Where Does the Energy Come From?Two Sources
• The natural passive geothermal gradient• The energy absorbed by the Sun!
6
The earth is like a solar battery absorbing nearly half of the sun’s energy. The ground stays a relatively constant
temperature through the seasons.
45% absorbed by
ground
Space
Atmosphere
Earth
U.S. Dept. of Energy
Passive geothermal gradient
7
Answers to QuestionsAnswers to QuestionsWhat makes ground-source heat pumps energy efficient?
Ground-coupled heat pumps take advantage of 2 ½ to 1 gain in energy output to energy input with the characteristics of heat transfer to fluid in the loop with the ground.
How does it Cool?Refrigeration circuit with phase changes moves energy from a “hot” source to a “cold” source even at high fluid temperatures (>95°F).
8
Ground Loop Temperature ProfileGround Loop Temperature Profile
30%-60% Lower Operating / Energy Cost40%-70% reduction in Green House Emissions Longer life span Greater ComfortLess Maintenance, Simplified ControlsBetter Aesthetics (no exposed outdoor equipment)LEED/Green Building solutions
Benefits of GSHP SystemBenefits of GSHP System
10
Internal Component of Internal Component of GeoExchange SystemsGeoExchange Systems
CV Air UnitsHorizontal HPVertical HPConsole HPRooftop HP
Hydronic UnitsWW HP
11
Cost and PaybacksCost and PaybacksInstallation cost ranges $10.00 to $20.00 / ft2
Operating costs $0.35 to $0.85 /ft2-yr Paybacks can be immediate to 5 years
Average: 5-8 yearsSome systems can be 8-12 years
Rebates Depend on local utilities
Tax CreditsFederal and some State
12
Project ConsiderationsProject ConsiderationsKnow the Design Parameters
Space Heating/Cooling• Air Distribution• Radiant Floor Heating• Hot Water/Chilled Water Integrated Systems
Other Auxiliary Loads• DHW• Snowmelt- Heat Rejection• Refrigeration
Performance indifferent when properly designed at the same EWTsEfficiency of equipment directly correlated to EWT Pond/Lake Loops or Plates
• Be cautious about Icing or OverheatingHorizontal Loops
• Sizing loop must account for frost depths, surface snow, seasonal amplitude temperature changes
14
Loop Fields (continued)Vertical Boreholes
• Least site restrictive due to greater depths for heat transfer
• Accounts for majority of all installation (>80%)• Typical 2” and 3” header lines
2” = 4-7 boreholes per header3” = 6-12 boreholes per header
• Generally like to be the lowest utility
Project ConsiderationsProject Considerations
15
Loop Fields (continued)Hybrid Configuration
• Combine any of three traditional loop field designs to help reduce cost
• Combine with condensing boiler/solar heating technologies in heating load dominant situations
• Combine with fluid coolers/cooling towers in cooling load dominant situations
• Due to increasing use, further research is underway
Project ConsiderationsProject Considerations
16
Loop Fields (continued)In certain situations, a retrofit may be site prohibitive.Combine energy efficiency improvementsPrevious energy efficiency improvements may PROHIBIT a feasible retrofit Consider electrical service upgrades
Controls• Basic T-stat operation• DDC with integrated internal/external controllers
27
The The CxCx PerspectivePerspectiveInternal (continued)
Space Temperature Control• Standard heating and cooling setpoints (5 diff.)• Single setpoint with autochangeover
28
The The CxCx PerspectivePerspectiveExternal
P/T Ports• Supply and Return Header lines
Pipe• Fusion Joints
Butt FusionSocket FusionElectro Fusion
• Reverse Return
Properly Flush and Purged
29
The The CxCx PerspectivePerspectiveExternal (continued)
Grout• Properly mixed
Periodic samples- independently tested by mfr (free service)
• Grouted from bottom to top• No native backfill or pea gravel (by preference)
Proper balanced headers at manifoldProper tracer wire/metallic tape
30
The Good, The Bad, The UglyThe Good, The Bad, The Ugly
31
Developing the Developing the ““SolutionSolution””Optimization of Energy Performance must consider:
Utility RatesEvaluation of ALL System interactions
Select a GSHP for the right applicationEnergy performance criteria can influence decisions that may be different for each applicationBecome cognizant and aware of real issues so that informed decisions can be madeUnderstand Peak Load Durations based on system configuration
32
International Ground Source Heat Pump Associationwww.igshpa.okstate.edu