Renewable Heat for Renewable Cities: Geoexchange Heating and Cooling: Introduction and Case Study of St Peters College Sports Centre

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1 : Geoexchange Heating and Cooling: Introduction and Case Study of St Peters College Sports Centre Presented by: Yale Carden, GeoExchange Australia Pty Ltd, 1 June 2016

2 Presentation Overview Start With Why: Our Preferred Future: Strategic Plan Geoexchange 101 The Project Cycle Results

3 Our Preferred Future: Strategic Plan we must consider environmental sustainability is one of the world s greatest challenges. must promote sustainability through educational programs and school operations. We must focus on minimising our carbon emissions and environmental footprint through energy, water consumption and waste recycling.

4 The Other Why: Cost and Performance Operations: Existing system becoming old and maintenance increasing Cost: Increasingly expensive to operate; Comfort: Uncontrollably warm in summer months

5 Geoexchange 101: Thermal Energy Thermal is energy too! Thermal energy can also be renewable not just gas and fossil fuels Thermal potential consists of: Heat sources (heating) Heat sinks (cooling) Thermal energy storage, including phase change materials Multiple thermal sources in the built environment

6 Geoexchange 101: The Basics Transfers heat from the earth into the building in winter (earth as heat source) Transfers heat from the building into the ground in summer (earth as heat sink) Geoexchange or low temperature geothermal NOT hot rocks Solar radiation not heat from the Earth s crust

7 The Geoexchange Cooling Cycle

8 The Geoexchange Heating Cycle

9 Ground Heat Exchanger

10 Energy Piles

11 Sewer Heat Recovery Also includes wastewater / treated effluent Not just heating cooling also possible 20-25C heat source / sink is common Match water flow to heating / cooling requirements Local projects using treated effluent: Hobart Aquatic Centre, Hobart Grand Chancellor Hotel, Hobart

12 District Geoexchange Systems

13 Total Loads (kwhrs) Thermal Energy Storage Annual storage Cooling (kwhrs) Heating (kwhrs) Heat Rejection Heat Extraction Heat Rejection Time (Months) Short term storage: Simultaneous or diurnal

14 GSHPs: Water to Water / Reversible Chillers (Pool)

15 GSHPs: Water to Air (Ducted) Units

16 The Geoexchange Project Cycle Pre-feasibility and Concept Design In-situ Thermal Response Test Geoexchange Design Building Services and GSHPs Ground Heat Exchanger Pumping Strategies Installation in 2 stages due to School terms and pool usage

17 Feasibility: Thermal Potential Approach Existing system uses ambient air Thermal potential approach considers the following: Gas; Ambient air (used for heat recovery); Ground with vertical borehole GHX; Ground with horizontal GHX; River water under existing irrigation license; Treated effluent. River water original preference. However, logistical and future-proof issues; Vertical GHX preferred over horizontal GHX Minimise impact on sport fields; Enable future expansion of system.

18 The Vertical Ground Heat Exchanger 45 boreholes at 70 m deep, 7 m spacings Thermally enhanced grout Reverse return manifolded as 5 sets of 9 Material: PE100, DN40 (boreholes) Material: PE100, DN (manifolds) Electrofusion joints

19 The Ground Heat Exchanger

20 The Ground Source Heat Pumps 2 x 150 kw water to water / reversible chillers 6 x various water to air (ducted) GSHPs Heat Recovery System Variable Speed Pumps

21 Energy Efficiency Opportunities Energy Efficiency Opportunities Geoexchange Plant Upgrade Fresh Air Heat Recovery Roof Pool Blanket Ducted GSHPs 8% 25% 56% 3% 8%

22 Contact Details Yale Carden GeoExchange Australia Pty Ltd Phone: Website: