Borehole Thermal Energy Storage(BTES) uses boreholes piped in series and arranged in concentric circles to store warm and cold water. The water is used to heat and cool a building when paired with a water source heat pump. This video explains the importance of concentric circles and how the system operates.

For a more in depth video of ATES please go to the whole building design guide
https://www.wbdg.org/continuing-educa...