What piping material is commonly used for GSHP underground earth loops?

The use of HDPE (High-Density Polyethylene) for ground source heat pump (GSHP) underground earth loops is primarily due to its durability, flexibility, and resistance to corrosion. HDPE is a type of plastic that can withstand the varying temperatures and pressures often found in subterranean applications, making it ideal for the heat exchange processes involved in GSHP systems. Additionally, HDPE is lightweight and easy to install, which also contributes to its popularity for this purpose.

While copper is an excellent conductor of heat and is sometimes used in similar applications, it is generally more costly and can be subject to corrosion, particularly in certain soil conditions. PVC, although used in various plumbing applications, does not have the same thermal conductivity as HDPE and may not perform as effectively under the conditions present in ground source heat pump systems. Steel, while strong and durable, is also susceptible to rust and corrosion unless coated or treated, making it less ideal for long-term underground applications compared to HDPE. This combination of factors illustrates why HDPE is the preferred choice for underground earth loops in GSHP systems.