In a geothermal heat pump system, what types of loops are present?

In a geothermal heat pump system, the correct answer implicates the presence of both a refrigerant loop and a water loop. This is due to the system's design and function, which relies on two key components to efficiently transfer heat between the ground and the building.

The water loop is responsible for circulating a heat-transfer fluid, typically water or a water-antifreeze mixture, through underground pipes. This loop absorbs heat from the ground in the winter and dissipates heat back into the ground in the summer. By utilizing the stable temperature of the earth, the system can operate more efficiently than traditional heating and cooling systems.

The refrigerant loop works in conjunction with the water loop. In the geothermal heat pump, refrigerant is circulated through the system, absorbing heat from the water loop and transferring it to the indoor environment, or vice versa, depending on whether heating or cooling is required. This dual-loop system enables optimal energy efficiency and performance by leveraging both water for heat transfer and refrigerant for thermal exchange.

The other options do not fully capture the complexity and functionality of a geothermal heat pump system, as they either suggest a singular component or a less efficient fluid for heat transfer, failing to represent the integrated design that maximizes energy efficiency.