A fridge doesn't make cold. It moves heat.
Follow one loop of refrigerant: the evaporator soaks heat out of the cabinet, the compressor lifts it, the condenser dumps it at the rear, and the expansion device lets the pressure fall so the loop can start again. Turn up the cooling demand, then open the door.
Cabinet temperature over time
What's happening
—
Heat goes in, heat goes out
Inside, the low-pressure refrigerant boils in the evaporator and takes heat from the cabinet air. The compressor squeezes that vapour so it becomes hot enough to shed heat to the room through the rear condenser. The warm liquid then squeezes through the thin expansion tube, where its pressure and temperature fall.
The thermostat keeps the air inside a narrow band, so the compressor does not run all the time: it cycles on and off. An open door lets warm air in, so the compressor runs longer and the rear gets warmer.
A teaching model, not a specification
The cabinet temperature, thermostat band, door leak and cooling effect are simple illustrative numbers, with model time sped up (about 4 model minutes per second). They show the shape of the behaviour, not the performance of any real refrigerator. Real appliances also have fans, defrost cycles, variable-speed compressors and more.
heat out ≈ heat removed from the cabinet + compressor work