Final answer:
When a refrigeration system fails to hold an applied vacuum, it means that there is a leak in the system. Heat transfer in a refrigerator occurs through the process of vaporization and condensation of a coolant. The heat is absorbed from the inside and exhausted to the outside.
Step-by-step explanation:
When a refrigeration system fails to hold an applied vacuum, it means that there is a leak in the system. In a refrigeration system, heat transfer occurs from the inside of the refrigerator to the outside. This is achieved through the process of vaporization and condensation of a coolant. The heat is absorbed from the inside of the refrigerator, causing the coolant to vaporize, and then it is exhausted to the outside as the coolant condenses.