In a heat pump cycle, how does the refrigerant move through the system?

The movement of refrigerant through the heat pump cycle occurs in a closed loop through designated components, making this the accurate choice. In a heat pump system, the refrigerant continuously circulates in a closed system, transitioning between various states (liquid and gas) as it absorbs and releases heat.

The cycle typically involves several key components: the evaporator, compressor, condenser, and expansion valve. The refrigerant starts as a low-pressure gas in the evaporator, where it absorbs heat from the environment and turns into vapor. Then, the compressor elevates its pressure and temperature, sending the refrigerant into the condenser. In the condenser, the refrigerant releases its heat and transitions back to a liquid state before passing through the expansion valve to lower its pressure again. This precise sequence ensures efficient heat transfer and continual movement of the refrigerant, which is essential for the functioning of the heat pump system.

The other options do not provide an accurate description of how a typical heat pump operates. Open-loop systems are not the standard configuration for residential heat pumps; they usually rely on the closed-loop system for efficiency and safety. Gravity is not the primary force moving the refrigerant; instead, it is the pressure created by the compressor that drives the flow.