What process occurs first in the thermal cycle of a vapor-compression refrigeration system?

In a vapor-compression refrigeration system, the thermal cycle begins with the evaporation of the refrigerant. This process takes place in the evaporator, where the refrigerant, typically a low-pressure gas, absorbs heat from the environment (the area to be cooled) and changes from a liquid state to a vapor state. This heat absorption effectively removes heat from the space, leading to a cooling effect.

As the refrigerant evaporates, it transitions into a gaseous state while drawing energy from the surroundings. Once the refrigerant is fully vaporized, it is then drawn into the compressor, marking the subsequent steps of compression, condensation, and expansion in the refrigeration cycle. This sequence is critical for the efficient operation of the system, as it ensures a continuous flow of refrigerant that enables the cooling process to occur effectively. Understanding this order is essential for grasping how vapor-compression refrigeration works.