Experimental study of shaft resistance of energy pile Poster Presentation Experimental study of shaft resistance of energy pile Presented by Saeed Yazdani Adviser: Professor Sam Helwany April 2018

Advantages and Disadvantages Experimental Test Results Conclusion Outline A Review on Buildings Energy Consumption Geothermal Energy and Energy Pile Advantages and Disadvantages Experimental Test Results Conclusion

World energy use Presented by IEA (2017) Building sectors

World energy use (IEA (2017)) fossil fuel consumed by buildings = 30% of global fossil fuel consumption Heating/Ventilation/Air conditioning (HVAC) accounts for 50% of building energy use in developed country.

Conclusion Building is in charge for a ≈30% of global and U.S. fossil fuel burning and associated CO2 emissions. 35%-50% of energy use in building is HVAC. HVAC represents an important opportunity to decrease energy used by buildings sector and reduce CO2 emissions. promoting building efficiency, new technologies for generating renewable energy and social awareness on the serious consequences of irrational use of energy (IEA). The major and traditional renewable energy sources available for buildings are solar energy, wind energy, geothermal energy and bio energy.

Advantages and Disadvantages Literature Review Outline A Review on Buildings Energy Consumption Geothermal Energy and Energy Pile Advantages and Disadvantages Literature Review Experimental Test Results

Geothermal Energy and Energy Pile Temperature is constant 30 ft below the ground surface: 63 °F

Geothermal Energy and Energy Pile

Geothermal Energy and Energy Pile The Energy Pile is one of the main methodologies to make use shallow geothermal energy. Secondary circuit Primary circuit

Geothermal Energy and Energy Pile Pile diameter: 0.5-1.6 m Pile length: 10-30 m Pile spacing: 2 m Pipe (high density polyethylene (HDPE)): Di: 20 mm and Do: 25 mm

Advantages and Disadvantages Literature Review Outline A Review on Buildings Energy Consumption Geothermal Energy and Energy Pile Advantages and Disadvantages Literature Review Experimental Test Results

Advantages and Disadvantages Environmentally beneficial, cost efficient, and socially acceptable. Help reduce fossil fuel demand, decreasing CO2 emissions Reduce conventional heating/cooling costs by two third Low maintenance and long lifetime

Advantages and Disadvantages Soil Pile Shaft capacity, Qs End bearing capacity, Qb Load from top building, Q Q=Qs + Qb Qs: (1) pile surface roughness (2) shear strength of soil-pile interface (3) contact force between soil and pile surface Qb: (1) soil shear strength (2) pile geometry

Advantages and Disadvantages Literature Review Outline A Review on Buildings Energy Consumption Geothermal Energy and Energy Pile Advantages and Disadvantages Literature Review Experimental Test Results Numerical Simulations

Experimental Test Results Step 1: Isotropic pressure Influence of temperature on clay response Step 2: Thermal loading Julabo Heat Pump Thermocouple Free Friction Piston Displacement Sensor Interior Circulating Coil Circulating Heating Fluid Pore stone Exterior Circulating Coil Sample Exterior Circulating Tubes Step 3: Deviatoric stress

Thermal loading influence on shear strength parameters of clay Experimental Test Results Main Results Thermal loading influence on shear strength parameters of clay Thermal loading Cohesion, c'(kPa) Friction angle, (°) 24°C 12.01 24.5 34°C 2.08 25.43 (24°C-34°C)-10 cycles ≈ 0 26.47 decrease increase

Experimental Test Results Influence of temperature on soil-pile interface response LVDT Load cell Heat Pump Clay specimen Insulating cover Flexible rubber tube Step 1: Normal stress Step 2: thermal loading Step 3: shearing Concrete plate

Experimental Test Results Main Results:

Experimental Test Results Z=5.5 m GWT Ground Pile subsection

Experimental Test Results Air supply Pile element Cylindrical container 3@19 mm INSTRON loading frame Confining cap JULABO heat pump Heat carrier fluid Circulating fluid tube 230 mm 70 mm 19 mm Clay 75.5mm Air-bag Step 1: Applying pressure on the top of soil Step 2: Thermal loading Step 3: Pile load test

Experimental Test Results Main Results: Table 1- Test description Test # Temperature Variation 1 24°C (Reference temperature) 2 34°C 3 (24-34-24°C)- 10 cycles 4 (24-34-24°C)- 20 cycles 5 (24-34-24°C)- 40 cycles

Advantages and Disadvantages Literature Review Outline A Review on Buildings Energy Consumption Geothermal Energy and Energy Pile Advantages and Disadvantages Literature Review Experimental Test Results Conclusion

Conclusion Temperature variations induced during energy pile operation can enhance the soil strength surrounding the pile as well as the frictional force mobilized at the contact area between pile and soil, referred to as shaft resistance. In addition to providing the majority of required cooling energy, energy piles presents significantly higher load-carrying capacity comparing to that presented by conventional piles. Thus, from loading capacity point of view, the smaller dimension may be selected for energy piles as compared with conventional ones. It makes energy pile perfectly cost efficient as they reduce both heating/cooling and construction costs. Additionally they have been found environmentally efficient as they utilize renewable energy source.