Closed-loop Wells

What is a Closed-loop well?

A Closed-loop well is a borehole with two parallel high-density polyethylene pipes (HDPE) grouted its full length. Typically there are two or more Closed-loop wells piped together. A water based glycol solution is pumped through the Closed-loop wells to the heat pump, which extracts heat energy from the fluid, dropping its temperature. When this cold fluid is returned to the Closed-loop well, heat energy in the ground naturally flows through the grout and HDPE pipe and into the fluid, warming it back up.

Benefits of a Closed-loop System

  • A closed-loop well is a completely closed system and can therefore be installed regardless of the condition of the bedrock or the quality and amount of ground water encountered.
  • These systems are effective for residential homes and large institutional buildings.**

*A borehole is a narrow shaft bored in the ground.

**Closed-loop systems are typically more expensive to build and less energy efficient than Standing Column Well systems.

closed loop well

Here is a diagram of a typical Closed Loop Well geothermal system utilizing a reverse return piping layout.