Final answer:
A heat pump transfers energy from a colder environment to a warmer one, using components like an evaporator and compressor to accomplish this through a refrigeration cycle.
Step-by-step explanation:
A heat pump works by transferring energy from one environment to another via a refrigeration cycle. Specifically, using work, a heat pump transfers energy by heat from a colder environment to a warmer environment. This process involves four main components in its heating mode: the evaporator, compressor, condenser, and expansion valve. In the outdoor coils (the evaporator), heat transfer Qc occurs to the working fluid from the colder outdoor air, converting it into a gas. The compressed gas is then subjected to increased temperature and pressure, moving it into the condenser inside the heated space. Since the gas's temperature is now higher than that of the room, the heat from the gas is released to the room as it condenses back into a liquid. Lastly, this working fluid is cooled down again as it passes through an expansion valve before heading back to the outdoor coils.