The refrigerator works like a heat pump. The compressor pushes the coolant with high pressure into the condenser on the rearside. The condenser becomes warmer.Further to the throttle valve and in the evaporator. At low pressure vaporizes the coolant even at -30 degree Celsius and withdraws warmth from inside of the refrigerator.
In the small gap behind the refrigerator had been even 33 degree Celsius.
The efficiency of a heat pump depends from the temperature difference between cold and warm side. The construction with the condenser on the rearside in a small gap is not optimal.