Final answer:
During the cooling cycle, the outdoor coil becomes colder.
Step-by-step explanation:
During the cooling cycle of a heat pump, the outdoor coil becomes colder.
The heat pump works by transferring heat from the indoor to the outdoor environment. As the electrically driven compressor raises the temperature and pressure of the gas, it forces it into the condenser coils that are inside the heated space.
The gas then condenses to a liquid, releasing heat energy and becoming colder. The liquid then flows back through an expansion valve to the outdoor evaporator coils, where it is further cooled through expansion.
Therefore, the outdoor coil becomes colder during the cooling cycle.