How does a geothermal heat pump function differently from conventional geothermal power generation?

• A. Geothermal heat pumps exchange heat with the ground for heating/cooling; conventional geothermal power extracts high-temperature steam for electricity.
• B. Conventional geothermal power extracts high-temperature steam for electricity.
• C. Geothermal heat pumps generate electricity directly.
• D. Geothermal heat pumps rely on air temperature.

Answer: (D)

Geothermal heat pumps operate by moving heat between a building and the earth, not by producing electricity. They use a buried loop to access the ground’s relatively constant temperature. In heating mode, heat is drawn from the ground into the building; in cooling mode, heat from the building is rejected into the ground. A heat pump then boosts or cools this heat to match indoor needs, delivering heating or cooling directly to the living space.

Traditional geothermal power generation, on the other hand, converts underground heat into electricity. It uses hot water or steam drawn from underground reservoirs to drive turbines, producing electrical energy rather than providing direct heating or cooling for a building.

Relying on air temperature isn’t how a geothermal heat pump works. While outdoor air can affect the building’s heat load, the system’s heat source/sink is the ground, whose temperature remains more stable year-round. This stability is what makes geothermal heat pumps efficient for heating and cooling, unlike methods that rely on changing air conditions.