Cost Effectiveness of Energy Piles in Residential Dwellings in Australia

The cost effectiveness of energy piles used as part of Ground Source Heat Pump (GSHP) systems in residential buildings is presented. Structural piles can be used with a dual purpose of providing support to superstructures and of exchanging thermal energy with the ground, thus minimizing capital cost of GSHP systems associated with drilling. To exemplify the economic potential of energy piles, a case study of a representative residential building is undertaken. Results show that energy pile GSHP systems render annual gains of about $600 to $2900 (US dollars) in comparison with other conventional heating and cooling systems. This paper also briefly demonstrates the reduced available thermal capacity of energy piles, compared to traditional borehole ground heat exchangers, due to their inherent short depth and close spacing between piles. Despite this limitations, energy pile GSHP systems are able to satisfy the thermal energy needs for space conditioning of residential buildings.

Keywords: Ground source heat pumps; Energy pile; Geothermal; Economic feasibility; Temperate climate