A ground-source heat pump (GSHP), also known as a geothermal heat pump, can have an impact on the temperature of the soil and groundwater in its vicinity. Here's how it affects them:
- Soil Temperature: During the operation of a GSHP, heat is extracted from or transferred to the ground, depending on whether the system is in heating or cooling mode. In heating mode, the heat pump absorbs heat from the ground and transfers it to the building, while in cooling mode, it absorbs heat from the building and transfers it to the ground. As a result, the soil temperature near the heat pump's ground loop can be affected.
Heating Mode: When the GSHP is in heating mode, the temperature of the soil near the heat exchanger or ground loop tends to decrease. This is because heat is being extracted from the ground to heat the building. As the heat is continually extracted, the soil temperature near the loop may gradually drop. However, the extent of temperature decrease is usually minimal and localized to the immediate vicinity of the loop.
Cooling Mode: In cooling mode, the GSHP extracts heat from the building and transfers it to the ground. This heat transfer can cause the temperature of the soil near the heat exchanger or ground loop to increase slightly. The soil in the immediate vicinity of the loop may experience a temporary rise in temperature due to the heat being transferred.
- Groundwater Temperature: The operation of a GSHP can indirectly affect the temperature of groundwater in certain cases. However, it should be noted that GSHP systems are generally designed to have minimal impact on groundwater temperature.
Closed Loop Systems: In closed-loop GSHP systems, a loop of pipes containing a heat transfer fluid (such as water mixed with antifreeze) is buried underground. The fluid circulates within the loop and exchanges heat with the ground. Since the loop is sealed, it does not directly interact with the groundwater. Therefore, closed-loop systems typically have no significant impact on groundwater temperature.
Open Loop Systems: In open-loop GSHP systems, groundwater is pumped from a well or water source, and its thermal energy is extracted by the heat pump before being returned to the ground via another well or discharged elsewhere. The groundwater temperature can be affected by the heat exchange process, particularly in large-scale applications. However, proper design and sizing considerations are taken into account to ensure that the impact on groundwater temperature remains within acceptable limits and complies with regulations.
Overall, the effect of a ground-source heat pump on soil and groundwater temperatures depends on factors such as the system's mode of operation, design, sizing, and environmental conditions. Professional installation and adherence to guidelines help minimize any potential impacts on the surrounding environment.