Characterization of helical steel pile performance under varying soil conditions

Abstract

Ground-Source Heat Pumps (GSHPs) are a clean alternative to traditional space heating and cooling technologies. GSHPs take advantage of relatively constant ground temperatures as a medium for heat exchange, in contrast to the use of highly variable air temperatures. Conventional systems use a heat pump paired with a borehole heat exchanger to exchange heat with the ground. Widespread use of these systems has been impeded by high initial costs and low short-term return on investment. Helical steel piles (HSP) are structural elements that are drilled into the soil to provide support to buildings. With only minor modifications, these structures have shown promise as a viable alternative to the use of the conventional borehole heat exchanger. At present, there is little understanding of the functionality and the optimal design of HSPs as heat exchangers under different soil properties such as heterogeneity, porosity and saturation content. Therefore, the focus of this paper is to investigate the performance of HSPs under different heterogeneous soil conditions using numerical analysis. This paper presents the results of a numerical study of HSP performance under varying moisture contents.