1. Geothermal HVAC: An Introduction Daniel Bernstein President Gaia Geothermal, LLC

2. www.gaiageo.com Presentation Overview  Geothermal: A Brief Introduction  Geothermal: What is it?  Geothermal Design Principles  Geothermal Feasibility Studies  How do I get more information about geothermal?

3. Gaia Geothermal, LLCwww.gaiageo.com Geothermal: An Introduction Geothermal also is known as “geoexchange” Geothermal is a space conditioning technology that uses the earth’s constant temperature to: a) heat and cool buildings (commercial/residential) b) provide domestic hot water c) heat pools and spas d) melt snow e) provide process chilled/hot water About 1.1 million installations in the U.S.

4. Gaia Geothermal, LLCwww.gaiageo.com Geothermal: An Introduction Requires only electricity Uses “extended range” water-source heat pumps to replace chillers, boilers, furnaces, hot water heaters, etc. Geothermal is valuable because heating/cooling/hot water represent ~ 60% of domestic energy use and ~ 1/3 of commercial energy use.

5. Gaia Geothermal, LLCwww.gaiageo.com Geothermal: An Introduction

6. Gaia Geothermal, LLCwww.gaiageo.com C02 savings from geothermal compared to other systems in an average US home averaged across 20 cities: GasPropaneOilElectricGeo Avg C02 emitted4.45.56.85.72.1 Tons saved via conversion to geo 2.33.44.73.6N/A % C02 reductions52%62%69%63%N/A 45-55% of residential CO2 emissions result from HVAC Geothermal reduces average residential C02 footprint by ~ 1/3 Geothermal: What is it?

7. Gaia Geothermal, LLCwww.gaiageo.com  12500 square foot office: 23 ton system CA ND Geothermal: What is it?

8. Gaia Geothermal, LLCwww.gaiageo.com Circuit Piping (usually ¾” or 1” IPS) Multiple Circuits (trenches or bores) Header Pit Reverse-Return Header Supply & Return Piping (usually 1-1/4” or 1-1/2” IPS) Foundation Penetration Equipment & Flow Center Geothermal: An Introduction Image courtesy of WFI, Inc.

9. Gaia Geothermal, LLCwww.gaiageo.com Comparison 04-05 to 06-07 Energy Usage – 37.3% Energy $ - 77% 206% increase in $/kbtuh Oakdale School- Normal Illinois Summer School Energy Data Courtesy of CM Engineering, Inc. Geothermal: An Introduction

10. Gaia Geothermal, LLCwww.gaiageo.com ~ 47% of the solar energy falling on our planet is absorbed by the Earth’s surface. Geothermal: What is it?

11. Gaia Geothermal, LLCwww.gaiageo.com This results in a nearly constant soil temperature below the surface. Geothermal: What is it?

12. Gaia Geothermal, LLCwww.gaiageo.com Geothermal HVAC uses this solar energy stored in the earth to create “the most energy efficient, environmentally clean and cost-effective space conditioning system” (U.S. EPA). Geothermal: What is it?

13. Gaia Geothermal, LLCwww.gaiageo.com Geothermal: What is it? Images courtesy of GeoEnergy Services, Inc.

14. Gaia Geothermal, LLCwww.gaiageo.com Geothermal: What is it? Images courtesy of GeoEnergy Services, Inc.

15. Gaia Geothermal, LLCwww.gaiageo.com Geothermal: What is it? Images courtesy of Climatemaster, Inc.

16. Gaia Geothermal, LLCwww.gaiageo.com Geothermal: What is it?

17. Gaia Geothermal, LLCwww.gaiageo.com Geothermal: What is it? Types of ground heat exchanger loops: Vertical Horizontal Ponds

18. Gaia Geothermal, LLCwww.gaiageo.com Geothermal: What is it? Images courtesy of Rocky Mountain Geothermal, Inc.

19. Gaia Geothermal, LLCwww.gaiageo.com Geothermal: What is it?

20. Gaia Geothermal, LLCwww.gaiageo.com Geothermal: What is it? Images courtesy of Rocky Mountain Geothermal, Inc.

21. Gaia Geothermal, LLCwww.gaiageo.com Geothermal: Design Principles Key Points Prior to Designing a System: 1)Realize that each geothermal system is unique and there is no cookie cutter approach to geothermal design 2)Accurate loads calculations are essential 3)Understanding of local geology is essential 4)Shortcuts lead to system failures 5)Temperature ranges are wider than those of standard HVAC systems 6)Oversizing is not an option

22. Gaia Geothermal, LLCwww.gaiageo.com Key Components: Loads Location EWTs Pipe/Borehole Spacing and Layout Geology: thermal conductivity grout conductivity ground temperature Modeling time period/Prediction Time Geothermal: Design Principles

23. Gaia Geothermal, LLCwww.gaiageo.com Thermal Conductivity Undisturbed Ground Temperature Entering Fluid Temperatures Grout Conductivity or Borehole Separation COOLING TOWER/BOILER HYBRIDS Adapted From: Geo-Heat Center OIT Modeling Time Period Geothermal: Design Principles

24. Gaia Geothermal, LLCwww.gaiageo.com Geothermal Feasibility Studies Step 1: Calculate Loads Step 2: Select Heat Pumps Step 3: Vertical, Horizontal or Pond Loops? Step 4: Premodeling- Best and Worst Cases Step 5: TC Tests: What, Why, When and How? Step 6: Design Optimization Step 7: Circulation Pump Sizing Step 8: Emissions and Financial Modeling

25. Gaia Geothermal, LLCwww.gaiageo.com Loads: Residential vs Commercial Residential loads determined by climate/bin data –Based on building structure and climate. Commercial loads determined by climate, structure and building use/internal gains/diversity –Oftentimes cooling dominated –Internal diversity should be studied Decoupled systems reduce loopfield requirements and raise COP (COP of 12 in some cases). Geothermal Feasibility Studies

26. Gaia Geothermal, LLCwww.gaiageo.com Peak Loads –The loads normally calculated for commercial buildings using boiler/chillers plants etc. Energy Loads –For Geothermal, we need energy loads to determine the total annual energy that is exchanged with the loopfield. –Without these data, loops are oversized or undersized. Oversized- expensive. Undersized- water temperatures extreme and system shuts down Geothermal Feasibility Studies

27. Gaia Geothermal, LLCwww.gaiageo.com CoolingHeating Total Cooling (kwh)Peak Cooling (kw)Total Heating (kwh) Peak Heating (kw) January 162139853510 340 February 1376910141210287 March 3109124417204217 April 57152296215066 May 9494631329722 June 124627367857 July 166545 389 00 August 15138037000 Sept 11185536516815 Oct 5997527517191205 Nov 2045911130598264 Dec 1532210248680301 total 863336 211095 Geothermal Feasibility Studies

28. Gaia Geothermal, LLCwww.gaiageo.com Example: Church vs Office –Same peak load, same location, same geology –Church used 2x a week –Office used 12 hours a day, 5 days a week –Office loopfield >>> Church Loop Geothermal Feasibility Studies

29. Gaia Geothermal, LLCwww.gaiageo.com Geothermal Feasibility Studies Step 1: Calculate Loads Step 2: Select Heat Pumps Step 3: Vertical, Horizontal or Pond Loops? Step 4: Premodeling- Best and Worst Cases Step 5: TC Tests: What, Why, When and How? Step 6: Design Optimization Step 7: Circulation Pump Sizing Step 8: Emissions and Financial Modeling

30. Gaia Geothermal, LLCwww.gaiageo.com Step 2: Heat Pump Selection Import loads data into your loop design software Software selects pumps for you Water to air AND water to water heat pumps –Automatically select heat pumps –Manually select heat pumps Pumps selected based on pump capacity, temperatures and flow rates. Geothermal Feasibility Studies

31. Gaia Geothermal, LLCwww.gaiageo.com Geothermal Feasibility Studies Step 1: Calculate Loads Step 2: Select Heat Pumps Step 3: Vertical, Horizontal or Pond Loops? Step 4: Premodeling- Best and Worst Cases Step 5: TC Tests: What, Why, When and How? Step 6: Design Optimization Step 7: Circulation Pump Sizing Step 8: Emissions and Financial Modeling

32. Gaia Geothermal, LLCwww.gaiageo.com General Site Awareness: Location, available space Hybrid systems Step 3: Vertical, Horizontal or Pond? Geothermal Feasibility Studies

33. Gaia Geothermal, LLCwww.gaiageo.com Vertical Projects Geothermal Feasibility Studies

34. Gaia Geothermal, LLCwww.gaiageo.com Vertical Projects Ideal when area is limited Geology – All Sand and Clay, Shales, Limestone, etc. Cost to drill Geology – Air rotary, Mud Rotary, Sonic Assets – Who is available to drill this project? Site layout – watch other subterranean structures Geothermal Feasibility Studies

35. Gaia Geothermal, LLCwww.gaiageo.com Horizontal Projects Geothermal Feasibility Studies

36. Gaia Geothermal, LLCwww.gaiageo.com Horizontal Projects Space – Run rough pre-model to estimate preliminary field size Available space – space requirements can be extremely large. Area usually at least 2-3 times the square footage of the conditioned space Assets – Who can perform large installations? Site layout – watch other subterranean structures Geothermal Feasibility Studies

37. Gaia Geothermal, LLCwww.gaiageo.com Surface Water Projects Geothermal Feasibility Studies

38. Gaia Geothermal, LLCwww.gaiageo.com Surface Water Projects Most likely better for cooling than heating Most cost effective system Assets – Who can perform installations? Need a fair sized body of water with adequate depth Determine depth, fluid capacity, recharge capacity from springs, etc. Geothermal Feasibility Studies

39. Gaia Geothermal, LLCwww.gaiageo.com Geothermal Feasibility Studies Step 1: Calculate Loads Step 2: Select Heat Pumps Step 3: Vertical, Horizontal or Pond Loops? Step 4: Premodeling- Best and Worst Cases Step 5: TC Tests: What, Why, When and How? Step 6: Design Optimization Step 7: Circulation Pump Sizing Step 8: Emissions and Financial Modeling

40. Gaia Geothermal, LLCwww.gaiageo.com Determine minimum and maximum loop length ranges Should be done even before a TC test is performed. Can use it to determine whether or not to conduct a TC test Used for putting together budgetary numbers for the potential system Easy to do with software Geothermal Feasibility Studies

41. Gaia Geothermal, LLCwww.gaiageo.com Example low TChigh TCdifference borehole footprint 140' x 180'140' x 160' borehole spacing 20' total bores 8172 bore depth 300' total length 24300'21600'2700' costs ($10/ft) $243,000$216,000$27,000 If TC test costs less than $27000, do it! If TC test costs more than $27000, don’t do it. VertSamplefromManual Geothermal Feasibility Studies

42. Gaia Geothermal, LLCwww.gaiageo.com Geothermal Feasibility Studies Step 1: Calculate Loads Step 2: Select Heat Pumps Step 3: Vertical, Horizontal or Pond Loops? Step 4: Premodeling- Best and Worst Cases Step 5: TC Tests: What, Why, When and How? Step 6: Design Optimization Step 7: Circulation Pump Sizing Step 8: Emissions and Financial Modeling

43. Gaia Geothermal, LLCwww.gaiageo.com What? –A test to determine the average thermal conductivity of the ground. –Usually for vertical systems. Can be performed for horizontal systems as well –Measures: –Ground temperature (undisturbed) –Conductivity (k) –how much heat flows through the soil –Diffusivity (α =k/pc) Ratio of thermal conductivity to volumetric heat capacity. How rapidly heat flows through soil. Why? –Allows you to design accurately Geothermal: How do you do it?

44. Gaia Geothermal, LLCwww.gaiageo.com When? –Should be performed if the TC test cost is less than the difference between the best case and worst case design scenarios How? –Transfer known amount of heat into a test loop and measure how much heat is absorbed by soil –Use depth and pipe size that you plan on using for final installation. The TC test borehole can be used in the final installation Geothermal Feasibility Studies

45. Gaia Geothermal, LLCwww.gaiageo.com Geothermal Feasibility Studies Step 1: Calculate Loads Step 2: Select Heat Pumps Step 3: Vertical, Horizontal or Pond Loops? Step 4: Premodeling- Best and Worst Cases Step 5: TC Tests: What, Why, When and How? Step 6: Design Optimization Step 7: Circulation Pump Sizing Step 8: Emissions and Financial Modeling

46. Gaia Geothermal, LLCwww.gaiageo.com Geothermal Feasibility Studies Appropriate EWTs Appropriate flow rates Stable soil temperatures over many years (vertical systems) Appropriate pipe sizing Accurate soil temps/TC values EWT/soil temperature relationship

47. Gaia Geothermal, LLCwww.gaiageo.com Geothermal Feasibility Studies Step 1: Calculate Loads Step 2: Select Heat Pumps Step 3: Vertical, Horizontal or Pond Loops? Step 4: Premodeling- Best and Worst Cases Step 5: TC Tests: What, Why, When and How? Step 6: Design Optimization Step 7: Circulation Pump Sizing Step 8: Emissions and Financial Modeling

48. Gaia Geothermal, LLCwww.gaiageo.com Geothermal: How do I get more information about it? International Ground Source Heat Pump Association (IGSHPA) (www.igshpa.okstate.edu) Canadian Geothermal Coalition (CGC) (www.geo-exchange.ca) Private Commercial Training/Consulting Organizations (www.groundloopdesign.com) (www.heatspring.com) Software (www.gaiageo.com)