Which geothermal system is employed where space isn't limited and consists of two pipes placed side-by-side in a trench (3 to 10 m)?

Which geothermal system is employed where space isn't limited and consists of two pipes placed side-by-side in a trench (3 to 10 m)?

• A. Horizontal close loop system
• B. Vertical closed loop system
• C. Open loop system
• D. Groundwater heat pump

Answer: (A)

A horizontal closed-loop system. When space is available, laying a loop of pipe in shallow trenches across the ground allows the heat from the soil to exchange efficiently with the circulating fluid. Placing two pipes side-by-side increases the surface area in contact with the earth, which boosts heat transfer between the soil and the fluid in the loop. Because the system is closed, the heat-transfer fluid remains contained, avoiding groundwater interaction and contamination. This setup is generally more cost-effective and practical than drilling many vertical boreholes or using open-water sources, provided you have enough space for the trench layout. If space were very limited or drilling was already planned, a vertical closed-loop or an open-loop groundwater approach might be chosen instead, but for a space-rich site, horizontal close-loop is the standard option.

A horizontal closed-loop system. When space is available, laying a loop of pipe in shallow trenches across the ground allows the heat from the soil to exchange efficiently with the circulating fluid. Placing two pipes side-by-side increases the surface area in contact with the earth, which boosts heat transfer between the soil and the fluid in the loop. Because the system is closed, the heat-transfer fluid remains contained, avoiding groundwater interaction and contamination.

This setup is generally more cost-effective and practical than drilling many vertical boreholes or using open-water sources, provided you have enough space for the trench layout. If space were very limited or drilling was already planned, a vertical closed-loop or an open-loop groundwater approach might be chosen instead, but for a space-rich site, horizontal close-loop is the standard option.