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Overcoming Hurdles Integrated Simulation-Based Design for Geothermal Heat Pump Systems Xiaobing Liu, Ph. D. ClimateMaster.

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Presentation on theme: "Overcoming Hurdles Integrated Simulation-Based Design for Geothermal Heat Pump Systems Xiaobing Liu, Ph. D. ClimateMaster."— Presentation transcript:

1 Overcoming Hurdles Integrated Simulation-Based Design for Geothermal Heat Pump Systems Xiaobing Liu, Ph. D. ClimateMaster

2 Agenda Background Geothermal heat pump Overcoming hurdles Integrated simulation-based design –Enhancements of eQUEST/DOE-2.2 –Verification and validation –Applications Summary and prospects

3 2007 Nobel Peace Prize goes to Al Gore and the U.N.'s IPCC for their efforts to spread awareness of man-made climate change, and to lay the foundations for the measures needed to counteract it. Global Warming Map Animation by NA

4 More and severer hurricanes, heat waves, floods, droughts, and tornadoes occurring Strong Hurricanes increasing as Global Warming worsens Image: NASANASA Our planet is changing … Sea level raising Greenland's ice sheet is thinning by up to 1m per year Image: NASANASA Glacier retreating Trift Glacier, Switzerland From left to right: 1948, 2002, 2006

5 What can we do to protect our sweet home – Earth?

6 How we use our resources and energy today makes difference in our world in the future “Humankind has not woven the web of life. We are but one thread within it. Whatever we do to the web, we do to ourselves. All things are bound together. All things connected.” - Chief Seattle

7 Uses solar energy stored in the earth and takes advantage of the nearly constant temperature just below the surface Geothermal Heat Pump System A smart solution for energy efficiency

8 “the most energy-efficient, environmentally clean, and cost-effective space- conditioning system” “produce the lowest carbon dioxide emissions, including all source effects, of all available space- conditioning technologies” (EPA, 1993) Geothermal Heat Pump System Equivalent to More trees Fewer carsGreater clean power

9 Overcoming Hurdles Hurdles in initial cost Hurdles in design –Cumulative loads required for sizing ground heat exchanger (GHX) is much more complicated to calculate than the peak loads –Performance of various type of GHX is affected by many factors and their design heavily relies on computerized calculation –Lack of GHX design required geology information –Unfamiliar with GHX related drilling and grouting technology Hurdles in the field –Struggles between GHX installation and other construction processes –Challenges in quality control/assurance of drilling and grouting –Intensive requirements for flushing, purging, and pressure testing of underground piping

10 Integrated Simulation-Based Design No hassles any more in transferring data among individual programs Test and optimize GHP system by evaluating its performance in virtual reality Estimate building loads using various tools/software Size ground heat exchanger using OTHER tools/software Integrated Simulation-Based Design “Under one roof”

11 Integrated Simulation-Based Design (Continued) Documented energy performance rating is required for LEED certification and energy efficiency incentives Integrated building energy system requires integrated design process Zero Energy Home GSHP ERV PV panel Better insulation Double low-e windows Compact Fluorescent Lights Energy efficient appliances The above illustration is from http://www.ideal-homes.com/

12 Credible –Building load calculation –GHX modeling –HVAC system simulation User-friendly Cost effective Integrated Simulation-Based Design (Continued) What kind of tool do We Need?

13 Water-air Heat pump library * Enhancements of eQUEST/DOE-2.2 Advanced GHX modeling technology* Improved water-air heat pump simulation Dedicated GHP reports  Other GHX models

14  Based on extended G-function algorithm Enhancements of eQUEST/DOE-2.2 Advanced model for vertical ground loop heat exchangers (VGLHE)  Various borehole field configurations  Analytical borehole thermal resistance calculation accounting for grouting material, borehole geometry, anti-freeze

15 Enhancements of eQUEST/DOE-2.2 Wizard Interface for Specifying VGLHE

16 For each heat pump H/C capacities, EER, COP, airflow, water flow, pressure drop, ESP, and etc at ARI/ASHRAE/ISO rated conditions Eight curves for performance at off-rated conditions Water-to-Air Heat Pump Library

17 Non-dimensional total and sensible cooling capacity as a function of entering fluid temperature Non-dimensional heating capacity as a function of entering fluid temperature Water-to-Air Heat Pump Library Example of Performance Curves

18 Wizard interface with intelligent defaults Hourly building loads calculation Size and simulate almost all HVAC systems including GHP system Graphical display and summary reports –Energy consumption –Peak Demand –Utility bill (based on given utility rates) Detailed comprehensive reports Key Features Enhanced eQUEST/DOE-2.2

19 Verification of newly implemented g-function based VGLHE model Sensitivity study through parametric runs Validate predicted whole building and GHP system energy consumption with monitored meter level data Validate predicted whole building and GHP system performance (including energy consumption, loop/room temperature, and etc) with detailed component level data * Verification and Validation Approaches * Ongoing process using monitored data from a fully instrumented Zero Energy Home.

20 VGLHE Model Verification Previous eQUEST (DOE 2.1E GLHE model) vs. HVACSIM + (extended g-function model) New eQUEST (extended g-function model) vs. HVACSIM + (extended g-function model) Verification and Validation

21 Validation with Meter Level Data (1) VGLHE 40 boreholes 5 by 8 grid 250’ deep 20’ spacing 4.5” bore diameter ¾” PE U-tube Standard grout Garrett Geothermal Buildings 20,000 sf office conditioned by 50 ton GSHP Verification and Validation Zoning Two floors 7 perimeter zones each floor 1 core zone each floor Each zone conditioned with individual water-air heat pump

22 Validation with Meter Level Data (2) Verification and Validation Monthly Electric Use (kWh) Annual Total Electric Use (kWh) MeteredPredictedError 249,920236,7905% Thermal Model 3-D view in eQUEST Garrett Geothermal Building

23 Applications  Building Type: Hotel  Area: 66,000 sf  Candidate HVAC systems PTAC with electric heater GHP with VGLHE  Equipment efficiency PTAC: EER 8.8 GSHP: EER 18.5; COP 4.0  Utility rates: OG&E PL-1 SL-5 HVAC Systems Comparison (1)

24 1: PTAC ($ 69,012) 2: GHP ($ 45,834) Applications HVAC Systems Comparison (2)

25 PTAC GHP Applications HVAC Systems Comparison (3) Fan Pump Cooling Heating DHW More energy savings if heat pump condensing heat is used for DHW

26 Applications HVAC Systems Comparison (4) High electric demand means lager transformer and wires Subject to demand charge

27 Applications GHP System Design (1) 157 town homes grouped in 18 buildings Varying in height from 2 to 4 stories Ranging in size from 1600 sf to 3517 sf Over twenty-six floor plans Challenges in design  Boreholes are limited in garage only  Attached homes but with individual loop for each home  Very short time for design Solution  Integrated simulation with customized VGLHE modeling Result  VGLHE size varies from 230 – 280 ft/ton depending on location, orientation, window/wall ratio of each town home

28 Applications GHP System Design (2) Unit 4 (3 stories) Unit 2 (3 stories) Unit 3 (2 stories) Unit 1 (3 stories)

29 Number of hours LFT within each temperature range Thermal Loads of VGLHE and Leaving Fluid Temperature Applications GHP System Design (3)

30 Annual Max. & Min. VGLHE Leaving Fluid Temp. [F] Applications GHP System Design (4)

31 Summary To overcome hurdles in GHP system design, eQUEST has been enhanced to facilitate the integrated simulation-based design process Extensive efforts have been conducted to validate the enhanced eQUEST and more intensive validation is ongoing The enhanced eQUEST is making revolutionary change in GHP system design

32 Prospects Further validation and development of eQUEST –Prediction of GHP system long-term performance –Hybrid GHP systems: combination of a variety of heat sink and/or source –Geothermal water-water heat pump with integrated domestic hot water heater –Other types of GHX, including horizontal loop, pond/lake, standing column well, and other emerging technologies

33 Tremendous opportunity for GHP, if: More energy-efficiency incentives More knowledgeable and responsible drillers More cost-effective drilling and grouting technologies Advanced procedure and equipment for GHX installation and testing Prospects Borehole Televiewer Intelligent Drilling Advanced bits From Craig E. Tyner at SNL

34 Since their introduction in the 1980’s, nearly 1 million Geothermal Heat Pumps have been installed in the United States This is equivalent to: Planting 1 million acres of trees Taking 2 Million cars off the road We Can do More…

35 Thank You! Questions?


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