It was extremely hot in my apartment the other day and when I opened the fridge, I had this idea to leave it opened to decrease the temperature in the room. But there is a catch, it doesn't work like that.
The problem is that the fridge operates in a cycle and transfers heat energy from lower temperature body to higher temperature body. The compressor changes the pressure in its closed circle, making it colder than the inside of the fridge, therefore abstracting the energy from it, to make it as cold as we want. The ''heat'' from the inside is then transferred to the room we are situated. The room with a closed fridge eventually gets warmer.
So what happens when we open the door?
In an ideal system, the temperature of the room in would stay the same, meaning if the efficiency of the compressor would be 100%. The heat would be transferred and added to the room, but the room and the fridge are all the same when the doors are opened. Therefore, we do not make the room colder.
But there is a catch, we do not have 100% efficiency, which leads to the fact that the compressor is emitting a certain amount of heat plus the heat generated by changing the pressure heats the room.
I believe you have already known that, but for those of you who did not:
Do not leave your refrigerator's door opened during the summer, you'll be making more damage than good.