What effect does noncondensable gas have in a refrigerating system?

In a refrigerating system, the presence of noncondensable gases can significantly impact performance. Noncondensable gases, such as air and other impurities, do not condense into a liquid at the operational temperatures and pressures within the system. When these gases are present in the condenser, they take up space that would otherwise be occupied by the refrigerant vapor.

This results in an increase in the pressure within the condenser because the refrigerant must work harder to condense against both the refrigerant vapor and the noncondensable gases. The accumulation of these gases leads to an elevation in condenser pressure, which subsequently affects the overall efficiency of the system. If the condenser pressure becomes too high, it can cause issues like reduced cooling capacity, increased energy consumption, and potential failure of the system over time.

In contrast, high suction pressure or low suction pressure would be more directly influenced by factors related to the flow of refrigerant and cooling, rather than the presence of noncondensable gases. The effect of noncondensables specifically within the context of this question pertains to the rise in condenser pressure, making it the correct and relevant effect in a refrigerating system.