The temperature inside a refrigerator is very low, allowing for low-temperature storage of food. So some people might wonder: Could opening the refrigerator door cool down the room in the hot summer? To answer this question, we first need to understand why refrigerators cool down. Opening the refrigerator door actually doesn't cool down the room.
The basic structure of a refrigerator includes four main components: an evaporator, a compressor, a condenser, and a capillary tube. These components are typically connected by copper tubes to form an independent space that does not come into contact with the outside air, which is filled with a material called refrigerant. In the past, refrigerants were mostly Freon 12 (dichlorodifluoromethane), but it was later found that it could damage the ozone layer and contribute to the greenhouse effect, so it was banned and replaced by Freon 134a (tetrafluoroethane).
Freon 134a has an interesting "property": When it is in the evaporator, it evaporates into a gas at -26.5°C, absorbing heat from the food and other items in the refrigerator, thus cooling down the interior. The compressor first compresses the Freon that comes out of the evaporator into high-temperature and high-pressure steam, which is sent into the condenser. The condenser transfers heat to the surrounding air and simultaneously cools down to liquid form, entering the very fine capillary tube and returning to the evaporator. In the evaporator, the volume suddenly expands, rapidly vaporizing and absorbing heat again, repeating this cycle to lower the temperature inside the refrigerator. During this process, the refrigerator continuously transfers heat to the surrounding air.
In this process, the heat from the food is absorbed by the Freon in the evaporator, then flows to the condenser, and finally transfers to the indoor air through the condenser. The flow of Freon is mainly achieved by the compression of the compressor, which uses electricity. When the compressor is working, some electrical energy is converted into heat and absorbed by the Freon, which is finally transferred to the air through the condenser. So in fact, the heat transferred to the air by the condenser is equal to the heat absorbed from the food plus the heat converted from electrical energy.
Understanding the working principle of the refrigerator, we can answer the above question. Obviously, opening the refrigerator door actually cannot reduce the indoor air temperature. Not only can't it reduce it, but because the refrigerator "discovers" that the internal temperature has risen, it will continue to work hard to "cool down" and make the indoor air temperature rise. So in the summer, let's still use the refrigerator to cool down our favorite drinks and food.