Long-Term Thermal Performance of Group of Energy Piles in Unsaturated Soils under Cyclic Thermal Loading

Geothermal energy piles (GEPs) are an environmentally friendly heat exchange technology that dualizes the role of structural foundation pile for load support and in meeting building heating/cooling need. Energy loops made from high-density polyethylene, which allow carrier fluid circulation, fitted into elements to extract or inject store soil surrounding pile. This paper reports results a numerical study investigating long-term behaviour group embedded unsaturated soils (sand clay) under continuous cyclic heating cooling load. Additionally, two scenarios were investigated where: (1) whole GEPs heated cooled collectively; (2) alternate cooled. It was found trend temperature magnitude at all observed locations decreases with time as result cycles. Furthermore, subjecting cycles lower development comparison thermally activating group. is attributed applied thermal load, 0.5 times considered first case. However, this might not be case where equal on cases investigated.