Energy, economic, and carbon emission analysis of a residential building with an energy pile system

This paper investigated the combined energy, economic and carbon performances of energy piles used for heating and cooling buildings, an issue that has received limited interest in the past. To address this knowledge gap, a 30-year numerical simulation, calibrated using field data, was conducted for variable building thermal loads, pile spacing, pile length and number of energy piles for a six-storey residential building in Melbourne, Australia. The energy pile system in the annual heating-only mode demonstrated a 75 % reduction in energy consumption and a 5 % reduction in energy costs compared to a natural gas boiler. The energy piles performances in the annual heating-and-cooling mode were significantly higher than in the heating-only mode, demonstrating a 39 % reduction in energy consumption, carbon emissions and energy costs compared to an air-source heat pump. Increasing the pile spacing from 2.05 m to 6.4 m, pile length from 10 m to 20 m, and number of energy piles from 38 to 114 increased the energy, economic and carbon benefits of energy piles by 76 %, 77 % and 119 %, respectively. The results highlight the importance of building thermal loads and pile configuration on assessing the energy, economic and carbon performances of energy piles during early design stages.