Experimental Characterization of Energy Output from a Model Geothermal Pile

Abstract

Geothermal piles are increasingly used around the world as an innovative and sustainable method of harvesting shallow geothermal energy. Energy harvested through this technique can be used to partially meet the heating and cooling energy demand for residential and commercial buildings. Despite the growing recognition of the benefits of geothermal piles, the complex heat exchange through these piles is not yet fully understood. This paper describes a series of thermal tests performed on an instrumented model heat exchanger pile installed in a standard F50 Ottawa sand bed. Temperature measurements were obtained at different locations within the soil, on the pile surface, on the tank boundary, and at the inlet and outlet points of the circulation tube. Recorded temperature data are used to obtain time-dependent heat exchange efficiency of the model pile. The thermal tests presented in this paper provide valuable data on the nature of heat exchange through geothermal piles and on the thermal response of soil in the vicinity of a heat exchanger pile.