Final answer:
The answer is a) True. Ground-source heat pumps can be used for heating and cooling in cold climates since they harness the relatively stable temperatures below the Earth's surface to efficiently transfer heat, regardless of air temperatures.
Step-by-step explanation:
A ground-source heat pump, often known as a geothermal heat pump, can indeed be used for both heating and cooling even in cold climates, making the answer a) True. These systems work efficiently across different climates because they transfer heat between the building and the ground or a water source nearby. Unlike traditional air-source heat pumps that rely on the variable outside air temperature, ground-source heat pumps leverage the more consistent temperatures found just below the Earth's surface. During colder seasons, they draw heat into the building from the ground, providing warmth. Conversely, in warmer seasons, they remove heat from the building and transfer it back into the ground, thus cooling the space.
Heat pumps, in general, use work to transfer energy by heat from a colder environment to a warmer environment. Traditional air-source heat pumps may struggle in very cold conditions because they have to work significantly harder to extract usable heat from the cold air. However, a ground-source heat pump's efficiency remains relatively high even in colder climates due to the smaller temperature differential (ΔT) between the constant ground temperature and the desired indoor temperature, which means they require less work to move heat.