Standing Column Well Systems Overview

Standing Column Well Systems

A Standing Column Well System, or SCW, is a hybrid of an open loop and closed loop configuration.  It resembles an open loop because the water drawn from the well is used as the medium for heat exchange and an antifreeze solution is not needed.  A SCW is similar to a closed loop in that it draws water from the well as the heat source, and returns it back to the same source after the heat has been extracted, which is also called the heat sink.[i] 

In general, all of the water that is withdrawn from the well for heat extraction is returned to the well, allowing for the water level in the well to remain relatively stable.  Some systems may be incorporate a bleed system, which allows for small amounts of water to be discharged into another well or other watercourse[ii].  The purpose of bleeding water from the system is to allow for more groundwater to flow into the well, bringing the overall water temperature closer to the design temperature for maximum system efficiency.  The need for bleeding water may be required to prevent the well water from dropping to temperatures that may be harmful to the heat pump or to simply increase the heat exchange capacity.

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[i] Rees, S.J., Spitler, J.D., Deng, Z., Orio, C.D., & Johnson, C.N.  (2004).  A study of geothermal heat pump and standing column well performance. American Society of Heating, Refrigeration, and Air-Conditioning Engineers Transactions: Research, 110, 3-13.

[ii] Rees, S.J., et al.  (2004).