When you unplug and turn off a refrigerator, both the refrigerator compartment and the freezer compartment will eventually reach room temperature. However, the freezer compartment might still appear colder than the refrigerator compartment for a short period after being unplugged. This phenomenon is due to the following reasons:
Insulation: The freezer compartment of a refrigerator is typically more heavily insulated than the refrigerator compartment. This extra insulation helps to keep the freezer colder for a longer time even when the power is disconnected. The insulation slows down the rate of heat transfer into the freezer, allowing it to retain its lower temperature for a while.
Mass and thermal inertia: The freezer usually contains more mass in the form of frozen items than the refrigerator does with its mostly non-frozen items. Frozen items have a high thermal mass, which means they can store more cold energy. When you unplug the refrigerator, the frozen items in the freezer act like a "thermal battery" that can help keep the freezer colder for a period of time.
Temperature difference: When a refrigerator is operating normally, the compressor and cooling system maintain a temperature difference between the freezer and refrigerator compartments. The freezer is kept at a much lower temperature than the refrigerator. When the refrigerator is unplugged, the temperature difference between the two compartments can be more noticeable for a short time until both compartments reach room temperature.
It's essential to note that after some time, both the refrigerator and freezer compartments will warm up to room temperature when the appliance is unplugged and turned off. The exact time it takes for them to reach room temperature will depend on various factors, such as the initial temperature, the amount of insulation, the surrounding environment, and the mass of items inside each compartment.