Underground Thermal Energy Storage (UTES) Opportunities in FL Utilizing Boreholes & Aquifers

Transcription

1 NW FL ASHRAE Chapter January 2017 Meeting Underground Thermal Energy Storage (UTES) Opportunities in FL Utilizing Boreholes & Aquifers Chuck Hammock PE, LEED BD+C, CGD Andrews Hammock & Powell, Inc.-Consulting Engineers January 10, 2017

2 Presentation Outline Direct-Use (American) Geothermal Heat Pumps (GHP) Architecture vs. Geothermal designed for true Thermal Storage (typically only done outside the US) UTES: Underground Thermal Energy Storage- designed to store heat or cold, diurnally or seasonally Aquifer Thermal Energy Storage (ATES) Systems Borehole Thermal Energy Storage (BTES) Systems UTES increases the efficiency of traditional (US style) GHP systems ESTCP UTES Projects Layered Thermal Conductivity Testing (LTCT) Distributed Temperature Sensing (DTS)

3 Primary Differences of Direct Use Geothermal Vs. UTES Geothermal Direct Use : Typical American closed loop piped in a grid with parallel flow or is a one-way open loop that can t capture waste heat/cold With UTES, Geology is still used at heat sink & heat source, but BTES/ATES is optimized to deliberately store cold or hot. Closed loop UTES (BTES) boreholes generally piped as 3-6 boreholes in series for deliberate thermal stratification or zones (bull's-eye) Open Loop UTES (ATES) or BTES has the capability to reverse the flow to charge or discharge its stored thermal resource

4 Brief Overview of TES/UTES Thermal Energy Storage (TES) can be: Above ground, below ground or both Sensible only, latent only or both Diurnal, Seasonal or Both In the Underground form, UTES is: Normally ATES or BTES but can be.. Hybrid UTES: Combine above ground and underground Storage (Drakes Landing) Pit Storage: 200,000 M 3, 85 C, Denmark) for heat or a cold version called Seasonal Snow Storage (SSS) 45 Contributors, One American Abandoned Mines or Flooded natural caverns (CTES) Energy Piles (basically a multi-purpose structural pile/btes system)

5 Germany s VDI-4640 Guidelines Underground Thermal Energy Storage Guidelines

6 Building Thermal Characteristics Cooling Dominated Buildings: Capturing the cold of winter and storing it in underground formations or aquifers and harvesting it in summer to cool the building Heating Dominated Buildings: Capturing the hot of summer and storing it in underground formations or aquifers and harvesting it in winter to heat the building Balanced Buildings: Do Both, especially with ATES Diurnal Load Variation? Do Diurnal Storage Seasonal Load Variation? Do Seasonal Storage. In reality most building obviously have both conditions

7 2015 by AH&P- Cannot be used without permission

8 Approximate Groundwater Temperature Isotherms

9 USGS Southeastern Geology

10 Aerial View of the Ft. Benning Building/ATES Site

11 Section/Detail of ATES Extraction and Injection Well Natural Gamma Radiation: CPS Confining Clay Layer Monitoring Well Piping Injection Valve Submersible Pump Intake Filter Screen with Gravel Pack 2015 by AH&P/IFT- Cannot be used without permission

12 Adiabatic Dry Cooler for BTES/ATES Applicatio n AirCooled DX Heat Reject. COP 100 BTES Max 1616 BTES Winter BTES Yr. Ave Annual Water Reduction BTES % Adiabatic Dry-Cooler with: Evaporative Cooling Coil Inlets. 18 Compartmentalized ECM Fans. (360 to 1 turndown), Modbus Interface

13 2015 by AH&P- Cannot be used without permission

14 When to consider BTES? Above 50 Tons? There probably is a min. size threshold before BTES should be considered, due to reversing valve, etc. cost, but theoretically, three thermal zones can be created with as few as 30 boreholes, therefore tons (typ.). Smallest/Largest by AH&P so far: 60/336 boreholes All Properties. BTES (unlike ATES) is a 50 state technology Anytime you are considering GHPs and/or have a good source of free heat or cold (CHPs, Solar, etc.) If smaller GHX footprint needed for your GHPs (due to closer borehole spacing since engineered for thermal storage not just heat extraction/dissipation). Ideally square/circular land availability, but the cylinder can be oval (VA s BTES-5) 14

15 BTES for non-ghp applications 15 Solar Thermal Application-Drakes Landing, Canada Hybrid with above ground thermal storage & BTES Combined Heat & Power (CHP) plant with BTES

16 Satellite Imagery of MCLB BTES System Under Construction Dec 2014 Google Earth Image 2

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18 BTES Construction Activities The two 30 high mountains in the woods/distance are actually the 20,000+ yd 3 of earth temporarily removed for the BTES Installation BTES: Outer Circular Headers(foreground), Radial Sub-mains (center) BTES Reversing Valves

19 Modular Heat Recovery Chiller

20 Temperature Plots of BTES Entering and Leaving Water & Charging/Discharging Modes In the next few slides, the blue line represents: The water at the perimeter of the BTES If the system is being charged with cold, this is the temperature leaving the outer boreholes. If the system is discharging its cold, this represents the warmer water entering at the outer borehole Conversely, the green line represents the water at the core of the BTES that is entering the core during charging and leaving the core during discharging Red shading represents cold discharging or heat going into the BTES (typical) Sample plot of water temperatures during cold discharging-only mode in early fall

21 Temperature Plots of BTES Entering and Leaving Water & Charging/Discharging Modes (continued) Sample plot of water temperatures during DIURNAL STORAGE times in late fall ( cold-discharging during the day & cold-charging at night) Shading represents charging, (cold storage) or heat being removed from the BTES (typical) Sample plot of water temperatures during continuous (24 hr/day) cold charging SEASONAL STORAGE mode in winter

22 Temperature Plots of Inner, Middle and Outer Borehole Delta T s Sample plot of water temperatures differentials across three boreholes in series charging the BTES in late fall with cold. The teal line is the delta T across the inner borehole, the green the middle borehole and the blue the outer borehole. The most heat transfer is occurring exactly where it is needed.at the core of the BTES

23 ESTCP s EW (BTES-1) 11 month results MCLB 23 Albany ( as of 30 June 2016) KBTUs/Ft 2 are down 48.1% even when this highly cooling-dominated building experienced a 14% increase in Cool. Deg. Days (CDD) and room temps kept 1 F colder. Combined annual elec., gas, water & maint. savings are $169k/year On-site gas consumption & emissions eliminated. So far, evaporative water consumption is zero a reduction of 5.1M gallons/yr., though we may chose to consume up to 1M gallons (20% of baseline per the ESTCP Demo Plan) to lower KWH/KWD further Current payback on $1.8M BTES cost is 10.7 years Technology Transfer : A+ with 4 more BTES system currently under design and scheduled to bid in late 2016

24 BTES-2/3/4 (NAVFAC); BTES-5 (VA) 66 Ton BTES 183 Ton BTES BTES-2 MCLB Albany GA BTES-3 MCLB Albany GA 56 Ton BTES BTES-4 MCLB Albany GA BTES-5 VA Perry Point, MD Oval BTES-5

25 Layered Thermal Conductivity Test (LTCT) or Distributed Thermal Response Test (DTRT) Possibly first ever conducted in US Marines Corps Logistics Base, Albany GA (MCLB) 110 m u-bend borehole heat exchanger adjacent to BTES A 72 hours LTCT was conducted between May 12 and 14, 2015 and heat pulse tracked via DTS. Layer-by-layer K values measured

26 Layered Thermal Condutivity Test (LTCT) Downhole Temperatures This contour diagram shows the fluid temperature along the whole heat exchanger over the time observed. Right hand side is after elements de-energized Outlet water from the U-bend (surface) Bottom of the U- Bend (Axis of Symmetry) Inlet Water into the U-Bend (surface) Possible Groundwat er Flow

27 Summary: LTCT Results Sections 1 and 4 present the highest thermal conductivity. 1 0,070 Thermal conductivity [W/mK] Borehole resistance [K/(W/m)] 2,28 Temperature profiles during thermal recovery indicate possible presence of groundwater flow in region ,11 0,12 0,07 0,10 0,11 0,12 1,67 1,58 1,67 1,59 1,86 2,24 Borehole resistance is 9 low considering the large borehole diameter 8 0,11 0,09 1,61 1,88

28 Distributed Temperature Sensing (DTS)

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30 Why use ATES or BTES vs. Standard Open and Closed Loop GEO at Your Facility?? Allows you to take same basic open or closed loop GEO that has been used for years and increase its efficiency, if properly modeled/engineered Via Cold Capture or Hot Capture, allows Geo to move beyond energy efficiency to a truly renewable architecture. Can eliminate cooling tower water usage, which general far exceeds domestic water use (3-6M gal) Proven technology used outside of the US for decades. Beyond superior source/sink, real storage Direct chilled water UTES systems, in the right climate(<52ºf ground temp), can reduce cooling KWH by 85%

31 Application Considerations at Your Facilities 31 Utilize GHPs with UTES, when you need to reduce KWH/KWD/Energy $ s/water/on-site Emissions BTES is 50 state tech, ATES is aquifer dependent GHPs/UTES can serve a building via small unitary (waterto-air) GHPs or central chilled/hot water Space HW heat most eff. if low temp./heat recovery Optimized if domestic/process HW loads present Must do TCTs, hourly building & GHX modeling Requires Const. Mgmt: Submit. Reviews, grout test, ASTM pressure testing, 4+FPS flush/purge, etc.

32 Questions and Answers! Chuck Hammock, PE, LEED BD+C, CGD -Andrews, Hammock & Powell, Inc. -Consulting Engineers -Macon, GA , Ext