What happens if there are non-condensables in the operating refrigeration system?

• A. The discharge pressure decreases
• B. The unit stops working completely
• C. The discharge pressure increases
• D. The efficiency improves

Answer: (C)

When non-condensables, such as air or other gases that do not liquefy under the system's operating conditions, are present in a refrigeration system, they directly affect the system's performance. Specifically, these non-condensables increase the discharge pressure because they occupy space in the condenser that would otherwise be taken up by refrigerant vapor.

In a typical condensation process, refrigerant vapor should condense into liquid at a certain pressure and temperature. However, the presence of non-condensables displaces some of the refrigerant vapor, requiring a higher pressure to achieve adequate condensation of the refrigerant. This elevated pressure can lead to several operational issues, including increased energy consumption and decreased efficiency of the refrigeration system.

Understanding this concept is crucial for technicians, as managing non-condensables is key to maintaining optimal performance and efficiency in refrigeration systems.